METSÄNTUTKIMUSLAITOKSEN JULKAISUJA COMMUN 1С ATI ONE S INSTITUTI FORESTALIS FENNIAE MEDDELANDEN FRÅN SKOGS FORSKNINGSINSTITUTET I FINLAND MITTEILUNGEN DER FORST LICHEN FORSCHUNGSANSTALT IN FINNLAND PUBLICATIONS OF THE FINNISH FOREST RESEARCH INSTITUTE PUBLICATIONS DE L'INSTITUT DE RECHERCHES FORESTIERES DE LA FINLANDE 79 HELSINKI 1974 METSÄNTUTKIMUSLAITOKSEN JULKAISUJA COMMUNICATIONES INSTITUTI FORESTALIS FENNIAE MEDDELANDEN FRÅN SKOGS FORSKNINGSINSTITUTET I FINLAND MITTEILUNGEN DER FORSTLICHEN FORSCHUNGSANSTALT IN FINNLAND PUBLICATIONS OF THE FINNISH FOREST RESEARCH INSTITUTE PUBLICATIONS DE L'INSTITUT DE RECHERCHES FORESTIfiRES DE LA FINLANDE 79 HELSINKI 1974 COMMUNICATION ES INSTITUTI FORESTALIS FENNIAE 79 79.1 Nousiainen, Juhani & Puranen, Juha & Tiihonen, Paavo. 1973. Koivutukkipuiden kuutioimismenetelmä. lieferat: Eine Kubierungsmethode fur Birkenblochholz 1—53 79.2 Paavilainen, Eero. 1973. Studies on the uptake of fertlizer nitrogen by Scots pine using 15N labelled urea influence of peat thickness and application time. Seloste: Tutkimuksia turpeen pak suuden ja levitysajankohdan vaikutuksesta männyn lannoite - typen ottoon 1 —47 79.3 Cunningha m, James P. 1974. An energetic model linking forest industry and ecosystems. Seloste: Metsäteollisuuden ja ekosystee mien välisen vuorovaikutuksen energiamalli. Resume. KpaTKoe H3JIOJKeHHe I—sl1 —51 79.4 Kurkela, Timo. 1973. Epiphytology of Melampsora rusts of Scots pine (Pinus sylvestris L.) and aspen (Populus tremula L.). Seloste: Männyn versoruosteen ja haavanruosteen epifytologia I—6B1 —68 79.5 Huuti, Olavi. 1973. Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen. Summary: The effect of field storage methods on initial development of planted spruce I—4l1 —41 79.6 Laasasenaho, Jouko. 1973. Unequal probability sampling by DBH cumulator. Seloste: Koepuiden valinta kuutiomäärän summaajalla I—2o1 —20 79.7 Hakkila, Pentti & Winter, Arja. 1973. On the properties of larch wood in Finland. Seloste: Suomessa kastatetun lehti - kuusipuun ominaisuuksista 1—45 KOIVUTUKKIPUIDEN KUUTIOIMIS MENETELMÄ JUHANI NOUSIAINEN, JUHA PURANEN JA PAAVO TIIHONEN DEUTSCHES REFERAT EINE KUBIERUNGSMETHODE FÜR BIRKENBLOCHHOLZ HELSINKI 1973 ISBN 951-40-0078-1 Helsinki 1973. Valtion painatuskeskus ALKUSANAT Koivutukkipuiden kuutioimismenetelmää koskeneet tutkimukset aloi tettiin metsäntutkimuslaitoksessa allekirjoittaneen Tiihosen johdolla jo 1950-luvulla. Tehtävää vaikeuttivat aikaisemmin käytetty mittayksikkö, erilaiset apteeraustavat ja keskittyminen yksinomaan puutavaralajitaulu koiden laadintaan. Ratkaisuun päästiin vasta vuoden 1972 alussa uuden mittayksikön, kiintokuutiometrin käyttöönoton ansiosta. Osoittautui, että menetelmää saatettiin soveltaa mm. leimikoiden pystymittauksissa. Laaja mittainen toiminta edellytti ATK-laskentaa. Käytännön mittaus- ja las kentatehtäviä silmällä pitäen katsottiin aiheelliseksi muodostaa allekirjoitta neista koostunut työryhmä, jonka toiminnan tuloksena on äskettäin val mistunut tämä tutkimusselostus. Tutkimuksen kenttä- ja laskentatöihin on osallistunut useita metsän tutkimuslaitoksen metsänarvioimisen tutkimusosaston palveluksessa olevia henkilöitä. Aineiston keruussa on saatu arvokasta tukea erityisesti Koivu keskukselta ja Oy Wil h. Schauman A b:n metsäosastolta. Valtion tietokonekeskuksen Oulun aluekeskuksen henkilökunta on suorittanut suurta kärsivällisyyttä edellyttäneen työn. Tutkimuksen käsikirjoituksen ovat lukeneet professorit Kullervo Kuusela ja Yrjö Vuokila. Julkaisun saksankielisen selostuksen ovat kääntäneet rouva Marianne Kahanpää ja fil. maisteri Yrjö Sihvo. Esitämme kunnioittavasti kiitokset saamastamme monipuolisesta tuesta. Helsinki, heinäkuu 1973 .Juliani Nousiainen Juha Puranen Paavo Tiihonen SISÄLLYSLUETTELO Sivu Johdanto 5 Aineisto 7 Kuutioimismenetelmän yleisperusteet 9 Menetelmän ATK-sovellutus 11 Yleistä 11 Laskennan lähtötiedot 12 Tietokonelaskennan logiikka 12 Tulostus 13 Tukkipuutaulukot 14 Laadintaperusteet 14 Taulukoiden rakenne ja käyttö 19 Kuutioimismenetelmän luotettavuudesta 21 Tunnusten mittaamisesta 21 Tarkistuslaskelmien tuloksia 25 Mittausten suorittamisesta 31 Kirjallisuusluettelo 32 Deutsches referat 34 Koivun tukkipuutaulukot 37 JOHDANTO Uuden mittausjärjestelmän käyttöönotto muutti tunnetusti myös pysty puiden kuutioimisperusteita. Leimikoiden pystymittauksissa sovellettu kuutioimismenetelmä oli kokonaan uusittava. Pystymittausten yleistyminen korosti lisäksi uusimisen kiireellisyyttä. Puutavaran mittaus sä ä 11 1 ö (163/69) edellytti metsäntutkimuslaitokselta uusien puutavaralaji taulukoiden valmistamista. Uusien mittausperusteiden ja menetelmien sel vittely katsottiin niin tärkeäksi tehtäväksi, että myös puun myyjiä ja osta jia sekä metsäntutkimuslaitosta edustavista henkilöistä koostuva, kuutioimisperusteiden yhdenmukaistamista v. 1970 käsitellyt työryhmä päätti jatkaa toimintaansa keväällä 1971. Työryhmän toiminnan tuloksena valmistui kesäkuussa 1972 kiintokuutiometrin käyttöön perustuva, lähinnä leimikoiden pystymittauksiin tarkoitettu mutta samalla yleensä pystypuiden kuutiointiin soveltuva menetelmä (Nousiainen et ai. 1972). Sitä on jo nyt sovellettu varsin suuressa määrin käytännön mittauksissa. Uuteen kuutioimismenetelmään sisällytettiin myös koivutukkipuita kos keva osamenetelmä. Toimintamahdollisuudet jäivät kuitenkin havupuihin verrattuna huomattavasti vähäisemmiksi. Koivutukkipuiden kuutioimis taulukoiden laadinnassa ei löydetty tyydyttävää ratkaisua. Jouduttiin rajoittumaan vain ATK-laskentaan, joka merkitsi kyllä olennaista etua. Tätä osamenetelmää koskevien, tähän mennessä suoritettujen tarkistus laskelmien tulokset ovat lisäksi varsin myönteisiä. Katsottiin, että laskelmia olisi pikaisesti jatkettava. Leimikoiden pystymittausten jatkuva lisääntyminen syyskaudella 1972 kiirehti osaltaan koivutukkipuiden kuutioimismenetelmän täydentämistä. Todettiin, että käytännön mittauksia saatettiin usein yksinkertaistaa, jos myös koivutukkipuut voitiin sisällyttää pystymittauksen piiriin samanlaisin mittausperustein kuin havupuutkin. Täydennyksen suorittamista korosti edelleen se seikka, että Maanmittaushallitus ja Keskus metsälautakunta Tapio päättivät kesällä 1972 ryhtyä käyttä mään laadittua kuutioimismenetelmää. Koivun tukkipuutaulukoiden laadintamahdollisuuksia koskevia tutki muksia jatkettiin metsäntutkimuslaitoksen metsänarvioimisen tutkimus osastossa kesä —syyskaudella 1972. Lokakuussa 1972 päädyttiin ratkaisuun, joka tarjosi perustan käytännön tarvetta vastaavien tukkipuutaulukoiden 6 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 laadinnalle. Koivutukkipuiden kuutioimismenetelmän täydentämistä päätet tiin jatkaa koko laajuudessaan. Aiheen monitahoisuuden vuoksi katsottiin aiheelliseksi muodostaa kirjoittajista koostuva työryhmä, jossa Nousiai nen ja Puranen keskittyivät erityisesti ATK-laskennan toteuttami seen ja Tiihonen vuorostaan kuutioimismenetelmän perusteita ja käyttöä koskeviin kysymyksiin. Tutkimustehtävää suoritettaessa ilmeni vähäistä tarkistuksen ja lisäysten tarvetta eräissä muissakin kuutioimismenetelmän perusteissa. Tehdyn rat kaisun mukaisesti liittyivät tukkipuutaulukoiden ja ATK-laskennan perus teet kiinteästi toisiinsa. Katsottiinkin, että aikaisemmin esitettyjen varsin suppeiden kuvausten (Nousiainen et ai.) täydentämisen asemesta oli selvempää laatia uusi, yhtenäinen koivutukkipuiden kuutioimismenetelmää käsittelevä tutkimusselostus. Se esitetään tässä julkaisussa. AINEISTO Tutkimuksen aineisto käsittää kaksi osa-aineistoa. Toinen koostuu tar kasteltavan kuutioimismenetelmän keskeisimpinä perusteina olevien Ilves salon (1947) »Pystypuiden kuutioimistaulukoiden» ja koivun kapenemis taulukoiden (Tiihonen 1961 b) koepuuaineistosta, jota jäljempänä kutsutaan tutkimusaineistoksi. Toinen on 13 koepuuerää käsittävä, maan eteläpuoliskon eri osissa sijainneilta käytännön hakkuutyömailta koottu tarkistusaineisto. Tutkimus- ja tarkistusaineisto sisältävät koepuita seu raavasti. Koepuiden jakaantumista erotettuihin luokkiin valaistaan jäljempänä kuutioimismenetelmän luotettavuuden tarkastelun yhteydessä. Jokaisesta tutkimusaineiston koepuusta on tehty seuraavat mittaukset: rinnankorkeusläpimitta, jäljempänä lyhennys d, pituus (h) ja kapeneminen (d—d 6), läpimitta 0.5, 2, 4, 6 . . . jne. metrin korkeudelta tyvestä lukien, ja mahdollisen kannon korkeus ja läpimitta. Kaikki läpimitat on mitattu kahdessa toisiaan vastaan kohtisuorassa suunnassa kuoren päältä millimetrin, pituus vuorostaan senttimetrin tark kuudella. Tarkistusaineiston koepuiden mittaus on suoritettu pääosiltaan edellä esitetyllä tavalla. Läpimittojen mittausta täydennettiin kuitenkin siten, että jakomielien jokaisesta rungosta erottama tukkiosa ja 6 cm:n läpimittaan (kuoren alta) asti ulotettu kuitupuuosa voitiin kuutioida erikseen. Lisäksi mitattiin tukkien pituudet ja läpimitat (keskeltä), joskin näitä mittaus tietoja on käytetty vain tukkiosan kuutioinnin tarkistukseen. Koepuiden lukumäärä Anzahl der Probe- Stämme Tutkimusaineisto — Hauptmaterial 1 761 Tarkistusaineisto — Kontrollmaterial v. 1966—67 mitatut koepuut — in den J. 1966—67 ermessene Probe- stämmc 1 191 v. 1972 mitatut koepuut — i. 1. 1972 ermessene Probestämme 2 131 Yhteensä — 1 nsgesamt 3 322 8 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 Läpimittojen ja pituuden mittauksen alkamiskohta on molemmissa osa aineistoissa sama Ilvessalon (mt.) soveltama puun juurenhaarojen määrittämä alin mahdollinen kaatokorkeus. Tarkistusaineiston rungot oli apteerattu yleensä puun myyjien ja osta jien järjestöjen (MTK:n metsävaltuuskunnan ja Koivukeskuksen) yhteisesti esittämien ohjeiden mukaisesti. Eräissä koepuuerissä oli sovellettu hieman tavanomaista pienempää minimiläpimittaa. Tästä ei kuitenkaan aiheutunut mitään haittaa, koska kuutioimismenetelmän laadinnassa ei nojauduttu edellä viitatun mukaisesti tukkien mittoihin. 2 1.5132—73 KUUTIOIMISMENETELMÄN YLEISPERUSTEET Tavoitteena oli menetelmä, jolla voitaisiin jakaa koivun rungon koko kuutiomäärä tukki- ja kuitupuuosan sekä käytön ulkopuolelle jäävän latvan kesken. Kysymystä on tarkasteltu varsin paljon aikaisemmin julkaistujen puutavaralajitaulukoiden (esim. Tiihonen 1966 a, 1969 a, 1969 b) laa dinnan yhteydessä. Kuutiojalan käyttö tukkiosan mittayksikkönä ja tukkien apteerausperusteiden vaihtelu aiheuttivat kuitenkin sen, ettei onnistuttu kehittämään riittävän yksinkertaista mutta samalla kohtuullisen luotettavaa kuutioimismenetelmää. Kiintokuutiometrin valinta uudeksi, kaikkien puutavaralajien yhteiseksi mittayksiköksi paransi ratkaisevasti kuutioimismenetelmän valmistamisen mahdollisuuksia. Määrällisten lukujen rinnalla tai asemesta voitiin nojautua suhteellisiin lukuihin. Laadinnassa saatettiin soveltaa jo aikaisemmin hahmo teltuja perusteita ja menetelmiä (A r o 1935; Tiihonen 1961 a, 1966 a). Niitä käyttäen määritetään ensin eri puutavaralajien suhteelliset osuudet ja siirrytään niistä sitten vastaaviin määrällisiin lukuihin. Keväällä 1972 tehdyt kokeet osoittivat, että koivutukkipuille voitiin valmistaa mainitunlaisen yleisperusteen mukaisesti ainakin ATK-laskentana suoritettava kuutioimis menetelmä. Tehdyn ratkaisun mukaisesti uuden kuutioimismenetelmän keskeisinä perusteina ovat Ilvessalon (mt.) »Pystypuiden kuutioimistaulukoiden» yksikkökuutiot ja koivun runkomuotoa kuvaavat kapenemissarjat (T i i hon e n 1961 b). Aikaisemmin oli jo valmistettu koivun latvan keski määräiskokoa osoittavat taulukot (Tiihonen 1972). Ne esitetään myös tässä julkaisussa (taulukko 1). Ns. peruskuutiomääränä on yhdenmukaisesti havutukkipuiden kuutioimismenetelmän kanssa (ks. Nousiainen et ai.) rungon käyttöosan kuutio (käyttöpuu), joka saadaan vähentämällä Ilves salon taulukoiden yksikkökuutiosta taulukon 1 mukainen latvaosa. Rungon käyttöosan kuutio jaetaan sitten tukki- ja kuitupuun kesken vas taavien %-osuuksien mukaisesti. Määrittäminen edellyttää neljännen tun nuksen käyttöönottoa varsinaisten kuutioimistunnusten, rinnankorkeus läpimitan, pituuden ja kapenemisen rinnalla. Tämä neljäs tunnus on tukki osan pituus. Kuutioimismenetelmään sisällytetään kuten havutukkipuillakin kaksi vaihtoehtoista laskentamenetelmää: numeeriset tau 10 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 Taulukko 1. Koivujen keskimääräinen latvaosuus (kuorineen). Tabelle 1. Durchschnittlicher Zopfanteil der Birke (mit Rinde). lukot eli tukkipuutaulukot ja ATK-laskentamenetelmä. Molemmilla vaihto ehdoilla päästään käytännöllisesti katsoen samoihin tuloksiin. Tukkipuu taulukoiden käyttöön liittyvä inter- ja ekstrapolointi saattaa aiheuttaa vähäisiä eroja ATK-laskennan tuloksiin verrattuna. Tarvittaessa voidaan erottaa kaksi alaluokkaa, normaalit ja poikkeuk selliset tukkipuut. Molempien laskentaperusteet ovat kuitenkin samat. Kuutioimismenetelmän mittayksikkönä on kuorellinen todellinen kiinto kuutiometri . Pituusluokka, cm m 7 » ii 13 15 17 19 21 «s M 27 «я 31 33 35 37 3!) 41 43 45 + Höhenklasse, m dm 3 kuorineen/runko — dm 3 mü Rinde!Stamm, 5 7 6 6 (j 8 7 7 6 7 9 8 8 1 8 10 8 8 7 6 9 11 9 8 7 6 6 10 12 9 8 7 7 6 5 4 11 13 10 8 7 7 6 5 4 4 4 12 14 11 9 7 7 6 5 4 4 4 4 4 13 16 13 9 8 7 6 5 4 4 4 4 4 4 4 14 17 14 10 8 7 6 5 4 4 4 4 4 4 4 4 4 15 17 15 11 9 8 6 5 4 4 4 4 4 4 4 4 4 4 4 16 16 12 10 8 6 5 4 4 4 4 4 4 4 4 4 4 4 4 4 17 16 12 10 8 6 5 4 4 4 4 4 4 4 4 4 4 4 4 4 18 13 11 9 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 19 12 9 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 20 9 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 21 9 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 22 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 23 7 5 4 4 4 4 4 4 4 4 4 4 4 4 4 24 5 4 4 4 4 4 4 4 4 4 4 4 4 4 25 5 4 4 4 4 4 4 4 4 4 4 4 4 4 26 5 4 4 4 4 4 4 4 4 4 4 4 4 4 27 4 4 4 4 4 4 4 4 4 4 4 4 4 28 4 4 4 4 4 4 4 4 4 4 4 4 4 29 4 4 4 4 4 4 4 4 -1 4 4 4 30+ 4 4 4 4 4 4 4 4 4 4 4 4 MENETELMÄN ATK-SOVELLUTUS Yleistä Koivutukkipuiden ATK-laskentamenetelmän kehittäminen perustettiin olettamukseen, ettei yksinomaan tavanomaisilla kuutioimistunnuksilla (d, d—d 6 ja pituus) vielä voida määrittää eri puutavaralajien usein suurestikin vaihtelevia suhteellisia ja määrällisiä osuuksia. Neljännen tunnuksen tarve oli ilmeinen ja metsäntutkimuslaitoksessa suoritettujen tutkimusten poh jalta päädyttiin tukkiosan päättymiskorkeuden eli tukki osan pituuden käyttöön. Miltei vastaavanlaista laskentaperustetta on aikaisemmin käy tetty poikkeuksellisten havutukkipuiden kuutioimismenetelmässä (N ou s i a i n e n et ai. 1972), missä tukki- ja kuitupuun rajakohtien määrittämi sellä pyritään osoittamaan se osa tai osat rungosta, josta tukkeja yleensä voidaan valmistaa. Tukkipuun mitat ja laatuvaatimukset täyttävistä rungonosista voidaan havupuilla useinkin käyttää vain osa tukeiksi, muun osan siirtyessä kuitupuuksi. Koivutukkipuilla tukkiosan pituus sen sijaan ilmaisee päättymiskorkeuden eli pituuden, johon asti runko kokonaisuudes saan luetaan tukkipuuksi. Koivutukkipuiden mittausohjeiden mukai sesti (MTK:n metsä valtuuskunnan...; Vanerikoivu jen...) ja käytännöllisistä syistä oli tukkiosan pituuden määrittämisessä syytä soveltaa sopivaa luokitusta. Neljännen tunnuksen valinnan jälkeen voitiin kuutioimismenetelmän laadintaa jatkaa, kuten edellä yleisperusteissa on lyhyesti todettu, Aron (1935) ja Tiihosen (1961 a) tutkimusten mukaisesti selvittämällä ensin eri puutavaralajien suhteelliset osuudet ja siirtymällä niistä sitten vastaa viin määrällisiin osuuksiin. Näin päädyttiin varsinaiseen laskentamenetel mään. Sen keskeisimmiksi perusteiksi tulivat Ilvessalon (1947) »Pystypuiden kuutioimistaulukot» ja Tiihosen (1961 b) laatimat, koi vun runkomuotoa kuvaavat kapenemissarjat. Menetelmän käyttökelpoi suutta tutkittiin ensin kapenemistaulukoiden koepuuaineiston perusteella. Lisäksi kerättiin erillinen tarkistusaineisto (ks. s. 7). Mainittuihin perusteisiin nojautuen tapahtui ATK-laskennan tekninen suunnittelu ja valmistaminen valtion tietokonekeskuksen Oulun alue keskuksen ja metsäntutkimuslaitoksen inetsänarvioimisen tutkimusosaston yhteistyönä kevät—syyskaudella 1972. 12 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 Laskennan lähtötiedot Koivutukkipuiden ATK-laskennan edellyttämät tiedot kootaan saman laisille lomakkeille kuin havupuiden mittauksessa. Runkolukusarja kootaan siten puidenluvun yhteydessä ao. lomakkeille. Rinnankorkeusläpi mittojen mittaus tapahtuu kuten jäljempänä tarkasteltavia tukkipuutaulu koita käytettäessä tavanomaiseen tapaan 2 cm:n tasaavin luokin. Koepuutiedot merkitään samoin kenttätöiden yhteydessä koe puulomakkeelle. Läpimittojen (d ja d 6) ja puun koko pituuden lisäksi merki tään lomakkeeseen tukkiosan pituus. Rungon tyviosaan rajoittuvan, 7 8 m:n korkeuteen asti ulottuvan tukkiosan pituus ilmaistaan koivutukkien mittausperusteiden mukaisesti 3 dm:n kerrannaisina (31, 34, 37 . . . jne.). Tukkiosan pituuden ylittäessä mainitun korkeuden tunnus ilmaistaan 0.5 m:n tasaavin luokin, luokkakeskusten ollessa täysiä ja puolia metrejä. Tietokonekäsittelyä varten tiedot lävistetään reikäkorteille, joilta ne siirretään tarkistuksia suorittavalla ohjelmalla magneettilevymuistille. Ennen varsinaisten kuutioimisohjelmien ajoa aineisto lajitellaan perus rekisteriksi. Tietokonelaskennan logiikka Tarkasteltava ATK-laskenta sisältää seuraavat toiminnot. 1. Ilvessalon »Pystypuiden kuutioimistaulukoista» haetaan rungon kuutioimistunnusten, rinnankorkeusläpimitan, pituuden ja kapenemisen (jäljempänä merkinnät d, h ja d—d 6) mukainen kuorellinen yksikkökuutio, josta vähennetään taulukon 1 mukainen käytön ulkopuolelle keskimäärin jäävä latvaosa. Tulokseksi saadaan rungon käyttöosan kuutio kuorellisina todellisina kiintokuutiometreinä. Laskenta jatkuu seuraavasti. 2. Rungon kuutioimistunnuksilla (d, h ja d—d 6) haetaan kapenemis taulukoista koivun runkomuotoa kuvaava prosenttisarja, johon lisätään 0.5 metrin korkeuden läpimittaa vastaava %-luku, 109. 3. Lasketaan prosenttilukuja vastaavat määrälliset, kuorelliset läpimitat millimetrin tarkkuudella. Tuloksiin tehdään ns. d6-korjaus, jolla tarkoite taan kapenemistaulukoiden sisältämien, 2 cm:n luokin ilmaistujen runko viivojen täsmentämistä seuraavasti: tyvestä lukien 2—6 m:n välillä kaavan mukaan, ja 100 Pi • de 100 — P6 79.i Koivutukkipuiden kuutioimismenetelmä 13 7 -f- m:n mittakorkeuksilla kaavan mukaan. Pi = prosenttiluku i-metrin korkeudella P 6 = » 6 » » de = kohdassa 2 lasketun d 6 ja mitatun d 6 erotus millimetreinä. 4. Täsmennettyjä läpimittoja käyttäen lasketaan rungon käyttöosan todellinen kuutiomäärä (k-m 3 kuorineen) 6 cm:n latvaläpimittaan (kuoren alta) saakka. Tuloksesta käytetään lyhennystä Vt. 5. Edellisessä käytettyjen läpimittojen ja ko. koepuulle määritetyn tukkiosan pituuden mukaisesti lasketaan vastaavasti tukkiosan kuutio määrä vt todellisina kiintokuutiometreinä. 6. Kuitupuuosa Lt saadaan todellisina kiintokuutiometreinä kaavalla: 7. Kohdissa 5 ja 6 esitetyt, kapenemissarjan perusteella lasketut tukki ja kuitupuuosat tarkistetaan kertomalla ne osamäärällä V/Vt. Tässä V on kohdassa 1 Ilvessalon taulukoita käyttäen saatu rungon käyttöosan tilavuus ja Vt kohdassa 4 kapenemissarjan mukaisesti laskettu vastaava kuutiomäärä. Esitetynlaisen tarkistuksen jälkeen tukki- ja kuitupuuosien summa on täysin sama kuin Ilvessalon taulukoiden pohjalta määri tetty rungon käyttöosan tilavuus V. Tulostus Tutkimuksen yhteydessä suoritetuissa laskelmissa sovellettiin aikaisem min käytettyä tulostustapaa (ks. Nousiainen et ai. 1972, s. 30). Tulostuslistan yläosasta nähdään tällöin mm. koivutukkipuiden runkoluku sarja ja d-luokittaiset yksikkökuutiot, alaosasta taasen seuraavat tulostukset. A = runkolajin nimi lyhennettynä B = runkolajin koodi D = tukkiosan kokonaiskuutiomäärä E = tukkiosan kuutiomäärä keskimäärin runkoa kohden K = kuitupuun kokonaiskuutiomäärä Sovellettua tulostustapaa on tarvittaessa muokattava vastaisten teh tävien mukaisesti. Toistuvasti mainiten kuutiomäärät ilmaistaan todellisina kiintokuutio metreinä. Pi —— • de Po Lt = Vt vt TUKKIPUUTAULUKOT Laadintaperusteet Koivun tukkipuutaulukoiden ns. peruskuutiomääränä on edellä mainitun mukaisesti rungon käyttöosan kuutio, joka koostuu tukki- ja kuitupuuosasta. Todettiin, että tiettyyn d-, pituus- ja kapenemisluokkaan kuuluvan rungon tukkiosan ja siten myös kuitupuuosan tilavuus (k-m 3 /runko) saattaa vaih della suurestikin. Harkittiin kahta vaihtoehtoista esitystapaa. Jokaiselle luokalle esitetään kuten havutukkipuiden taulukoissakin vain yksi tukki- ja kuitupuuosaa osoittava lukupari. Toinen vaihtoehto edellytti useiden tukki ja kuitupuuosia ilmaisevien lukuparien määrittämistä. Samassa d-, pituus ja kapenemisluokassa erotettaisiin siis vaihteleva määrä tukkiosan pituuden mukaisia luokkia. Tavallaan kolmantena vaihtoehtona tutkittiin kahden sellaisen lukusarjan esittämismahdollisuutta, joista toinen kuvaa tukkiosan ja toinen rungon koko käyttöosan yksikkökuutioita. Todettiin, että kaksi viimeksi mainittua olivat ensimmäistä vaihtoehtoa edullisemmat. Luokkien perusteita ja lukumäärää koskevissa selvityksissä kiinnitettiin ensin huomiota seuraavasta asetelmasta nähtävään, Aron (1935, s. 81) esittämien tutkimustulosten perusteella saatuun lukusarjaan, joka osoittaa, kuinka monta prosenttia koivun rungon käyttöosan kuutiomäärästä keski määrin jää esitettyjen suhteellisten pituuksien alapuolelle. Nisula (1967 a) on laskenut vastaavanlaisia prosenttisarjoja Tiiho sen (1962) laatimien, rinnankorkeusläpimittaan ja pituuteen perustuvien kapenemissarjojen perusteella. Tulokset ovat varsin yhdenmukaiset Ar o n (mt.) keskimääräissarjojen kanssa. Tarkastelua jatkettiin tämän tutkimuk sen aineiston avulla laskemalla pätkittäisellä kuutioinnilla rungon tyvestä lukien 3, o, 7, 9 m jne. aina 2 m:n välein suurenevia runkopituuksia vastaa via kuutiomääriä. Määrällisiä tuloksia esitetään jäljempänä kuutioimis Suhteellinen pituus tyvestä lukien. % Relative Länge vom Zuschnitt aus gerechnet , % 10 20 30 40 50 60 70 80 90 Pituusprosenttia vastaava osuus rungon käyttöosasta, % Dem Längenprozent entsprechender Anteil am Nutzteil des Stammes, % 20 40 52 71 82 89 93 97 99 79.i Koivutukkipuiden kuutioimismenetelmä 15 menetelmän luotettavuuden tarkastelun yhteydessä. Tässä rajoitutaan vain edellisessä asetelmassa esitetynlaisiin suhteellisiin osuuksiin. Laskenta tavasta johtuen tulosten ryhmittely on tapahtunut suhteellisten pituuksien asemesta rungon todellisten osapituuksien mukaisesti. Ryhmittely tavasta riippuen samaan luokkaan sisältyy erivahvuisia, eripituisia tai erimuotoisia runkoja. Tulosten esittelyssä rajoitutaan vain seuraavasta asetelmasta nähtäviin, tutkimus- ja tarkistusaineiston kaikki koepuut yhdistäen saatui hin keskimääräistuloksiin. Suhteellista kuutiomääräosuutta ilmaisevien tulosten mukaan koivu tukkipuiden tyviosa käsittää varsin huomattavan osuuden rungon koko kuutiomäärästä. Tyvestä B—lo m:n korkeuteen ulottuva osa on rungon koko kuutiomäärästä n. 65—75 %, tukkiosasta vieläkin enemmän. Tyviosan suurehko osuus koko tukkiosan kuutiomäärästä antoi aiheen jatkaa tukkiosan pituuden mittauksen mahdollisuuksien tarkastelua. Todet tiin, että 6 m:n läpimitan määrittämisessä käytettävällä 5 m:n tangolla voi daan mitata ainakin 7 m:n korkeus vielä hyvin tarkasti. Silmävaraisesti arvioiden tai pidentämällä tankoa esim. metrin pituisella kevyellä lasikuitu kepillä on mahdollista päästä aina B—lo metriin. Tukkiosan pituuden mit taukseen liittyvät virheet saatetaan siis rajoittaa varsin vähäisiksi. Rungon tyviosaan rajoittuvasta lyhyehköstä tukkiosasta (tukista) voi daan mitata pituuden lisäksi myös läpimitta, jolloin kuutiointi olisi mahdol lista suorittaa pituus X läpimitta-periaatteen mukaisesti. Tätä kuutioimis tapaa on tutkinut mm. Tiihonen leimikon pystymittausta käsittelevien ohjeiden laadinnan yhteydessä (Kuronen... 1970). Tuloksia havain nollistavat kuvissa 1 ja 2 esitetyt kaksi esimerkkiä. Selvitysten yhdistelmänä todettiin, että yli 15 m pitkiä tukkiosia lukuunottamatta läpimitta oli mitattava noin 0.5 m kuutioitavan tyviosan puolivälin alapuolelta. Täsmäl leen puolivälistä mitatun läpimitan mukaisesti kuutioiden päädytään siis lievään aliarviointiin. Vastaavaan tulokseen on vaneritukkien osalta pääty nyt myös Nisula (1967 b). Tyviosan kuutioimismahdollisuudet liittyivät myös laadittavien kuutioi mistaulukoiden luokkien lukumäärää koskeneeseen tarkasteluun. Katsottiin, että taulukoihin oli sisällytettävä erityisesti B—lo m:n ylittäviä tukkiosan pituuksia vastaavia yksikkökuutioita. Kuitupuuosan määrittämisen tarve, läpimitan mittauskohtaan liittyvä vähäinen epävarmuus ja käytännölliset Aineisto Etäisyys tyvestä, m Material Entfernung vom Zuschnitt., m 5 7 9 11 13 15 Osuus kuutiomäärästä keskimäärin, % Durchschnittsanteil an der Kubikmasse, % Tutkimusaineisto — Hauptmaterial 44. » 58.7 70.6 80.6 88.2 93.7 Tarkistusaineisto — Kontrollmaterial 46.3 60.6 71.6 81.6 89.2 94.4 16 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 Kuva 1. Esimerkki pätkittäisen sekä pölkyn pituuden ja sen a) keskikohdalta tai b) ½ m keskikohdan alapuolelta mitatun läpimitan mukaisen kuutioinninriippuvuudesta.Koivu,tyvestälukien 5 m pölkky. Abb. 1. Beispiel von der Korrelation zwischen der sektionsweise Kubierung und der auf der Länge und dem Durchmesser des Blochs fussenden Massen aufnahme a) Durchmesser in der Mitte des Blochs gemessen,b)Durchmesser ½ munterhalbder Mitte des Blochs gemessen. Birke, Wurzelbloch 5 m. г 250 dm 3 / p250 dm 3 / Kuutioimisperusteina pituus ja läpimitta pölkyn keskeltä X Kuutioimisperusteina pituus ja läpimitta у 1 /гт pölkyn keskikohdan alapuolelta . /' / Grundlagen der Massenaufnahme Länge des Blochs und Durchmesser in der Mitte /•у ' Grundlagen der Massenaufnahme ' Länge des Blochs und Durchmesser y. ' '/гт unterhalb der Mitte ' - 150 /• f «• -150 f ' >4* a. yC b. _ 50 /f' -50 /1 Pätkittäinen kuutiointi J? Pätkittäinen kuutiointi Sektionsweise Kubierung / Sektionsweise Kubierung £ / 50 150 I I 250 dm /50 150 f 1 1 250dm 3 79.i Koivutukkipuiden kuutioimismenetelmä 17 3 13132—73 Kuva 2. Esimerkki pitkittäisen sekä pölkyn pituuden ja sen a) keskikohdaltataib)½ mkeskikohdan alapuolelta mitatun läpimitan mukaisen kuutioinninriippuvuudesta.Koivu,tyvestälukien 12 m pölkky. Abb. 2. Beispiel von der Korrelation zwischen der sektionsweise Kubierung und der auf der Länge und dem Durchmesser des Blochs fussenden Massen aufnahme a) Durchmesser in der Mitte des Blochs gemessen , b) Durchmesser y 2 m unterhalb der Mitte des Blochs gemessen. Birke , Wurzelbloch 12 m. 18 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 näkökohdat korostivat toisaalta sitä, että tyviosan pituuden ja läpimitan mukaista kuutiointia olisi vältettävä mahdollisuuksien mukaan. Siten myös pienille d-luokille oli aiheellista muodostaa tukkiosan pituusluokkia, vaikka tukkiosan pituus niillä usein alittaakin edellä esitetyn B—lo8 —10 m:n rajan. Koska esitettyä pituuden ja läpimitan mukaista kuutiointia kuitenkin ilmeisesti tarvitaan ainakin laajamittaisessa toiminnassa, katsottiin aiheelli seksi laskea taulukosta 2 ilmenevät, varsinaisiin taulukkoihin liittyvät yksikkökuutioiden sarjat. Laadittua erillistaulukkoa voidaan tarpeen mukaan täydentää tai supistaa. Toisena luokitusta koskevana tarkastelukohteena olivat tarkistus aineiston perusteella d-, pituus- ja kapenemisluokittain lasketut, tukkiosan keskimääräistä pituutta osoittavat lukusarjat. Pyrittiin myös hahmottele maan kuva tukkiosan pituuden vaihtelusta ja maksimiarvoista. Ilmeni, että tukkiosan pituus on pitkissä, hyvälaatuisissakin puissa yleensä alle 20 m. Lopuksi kiinnitettiin huomiota taulukoiden esittämistapaan. Jo kahden tukkiosaa ilmaisevan pituusluokan muodostaminen johtaa esim. havutukki puiden taulukkoihin verrattuna huomattavasti laajempiin taulukkoihin. Koivutukkipuiden taulukoissa tulee näet jokaiseen luokkaan kaksi yksikkö kuutiota, joko tukki- ja kuitupuuosa tai tukkiosa ja rungon koko käyttöosa. Kovin monien tukkiosan pituusluokkien esittäminen ei ollut siis käytän nöllisistä syistä perusteltua. Suoritettujen tarkastelujen yhdistelmänä päätettiin muodostaa d-, pituus- ja kapenemisluokittain kolme tukkiosan pituusluokkaa, joiden väli on 2 m. Todettiin, että tällaisen luokituksen pohjalta suoritettu inter- ja ekstrapolointi on ainakin I—2 m:iin asti kohtuullisen luotettavaa. Muo dostetut kolme luokkaa peittävät siis tukkiosan pituuden vaihtelualuetta ainakin kuuden metrin pituudelta. Taulukko 2. Lyhyiden tukkiosien kuutioimistaulukko. Tabelle 2. Massentafeln für Bäume mit kurzen Blochholzanteilen. Tukkiosan Läpimitta kuoren päältä, cm — Durchmesser mit Rinde, cm pituus, m Länge des 17 21 23 25 27 29 31 33 35 37 39 Blochholz- anteiles k-m 3 kuorineen — Fm. mit Rinde 3.5 0.079 0.099 0.121 0.145 0.172 0.201 0.231 0.264 0.299 0.337 0.376 0.418 4.0 .091 .114 .138 .166 .196 .229 .264 .302 .342 .385 .430 .478 4.5 .102 .128 .156 .187 .221 .258 .297 .340 .385 .433 .484 .538 6.0 .114 .142 .173 .208 .246 .286 .330 .378 .428 .481 .538 .598 5.5 .125 .156 .190 .228 .270 .315 .364 .415 .470 .529 .591 .657 6.0 .136 .170 .208 .249 .295 .344 .397 .453 .513 .577 .645 .717 6.5 .148 .185 .225 .270 .319 .372 .430 .491 .556 .625 .699 .777 7.0 .159 .199 .242 .290 .344 .401 .463 .528 .598 .673 .752 .836 7.5 .170 .213 .260 .311 .368 .430 .496 .566 .641 .722 .806 .896 8.0 .182 .227 .277 .332 .393 .458 .529 .604 .684 .770 .860 .956 79.i Koivutukkipuiden kuutioimismenetelmä 19 Viimeisenä tarkastelukohteena oli kuitupuuosuus. Selvintä oli esittää se jokaiselle luokalle erikseen. Edellä tehdyn ratkaisun mukaisesti jokaisesta sovelletun d-, pituus- ja kapenemisluokituksen mukaisesta rungon käyttö osan kuutiosta erotetaan kolme erisuurta tukkiosan kuutiota. Kutakin tukki osaa vastaava kuitupuuosa voitiin ilmaista erikseen. Toisena vaihtoehtona oli esittää kolmen kuitupuuosuuden asemesta vain yksi luku, nimittäin ko. luokan rungon koko käyttöosan kuutio. Taulukon yksikkökuutioiden luku määrää voitaisiin siten huomattavasti pienentää. Inter- ja ekstrapolointi rajoittuisi samalla vain tukkiosaan. Koko käyttöosaa ilmaisevia yksikkö kuutioita voidaan käyttää myös muissa kuutioimistehtävissä. Päädyttiin jälkimmäiseen ratkaisuun, jonka mukaisesti luokittain esitetään koko käyttö osan kuutio ja siitä erotetut kolme tukkiosan yksikkökuutiota. Luokittaiset tukkiosat määritettiin ATK-laskennalla. Yksikkökuutioiden sarjoja tutkittiin vielä graafisesti. Tarkastelun perusteella poistettiin eräiden vierekkäisten sarjojen välillä ilmenneet vähäiset epäsäännöllisyydet. Tukki osan pituutta ilmaisevien luokkien määrää supistettiin lopuksi vähäisessä määrin muutamissa erotetuissa d- ja kapenemisluokissa. Lopulliset koivun tukkipuutaulukot on liitetty julkaisun loppuun. Taulukoiden rakenne ja käyttö Laadituista taulukoista ilmenee sovelletun luokituksen mukaisten run kojen keskimääräinen tukkiosa ja koko käyttöosa kuorellisina (todellisina) kiintokuutiometreinä. Kuitupuuosa saadaan vähentämällä koko käyttöpuun määrästä tukkiosa. Tukkiosan määrittämisessä nojaudutaan puun myyjien ja ostajien järjestöjen yhteisesti esittämiin ohjeisiin (MTK:n metsä valtuuskunnan . . .). Taulukoilla kuutioitavien koivujen on täy tettävä seuraavat minimirungon vaatimukset: pienin d-luokka 19 cm (18 —20 cm), ja rungosta saadaan vähintään 340 X 17 cm:n kokoinen tukki (läpimitta latvasta kuoren päältä kapeimmalta puolen), josta ainakin 1.5 m on 11, muilta osin 111 laatuluokkaa. Minimitukki on 310 X 17 cm (läpimitta keskeltä kuoren päältä). Kuitupuuosa ulottuu 6 cm minimiläpimittaan (kuoren alta) saakka. Todettakoon, että minimiläpimitan mahdollinen suurentaminen 7 cm:iin kuoren päältä pienentäisi kuitupuuosaa aivan vähäisessä määrin. Muutok sella ei kuitenkaan ole koivutukkipuiden osalta taloudellista merkitystä. Taulukoiden luokitus on seuraava: rinnankorkeusläpimitta (d-) luokat: 19—45 cm, 20 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 2 cm:n tasaava luokitus, pituusluokat: 15—27 m, metrin tasaavin luokin, —kapenemi s 1 vi o k a t (d —d 6): 2—9 cm. senttimetrin tasaavin luokin, ja tukkiosan pituusluokat: pääosiltaan kolme tyvestä lukien määritettyä pituutta, joiden väli on 2 m, vähäisessä määrin on erotettu vain I—21—2 luokkaa. Läpimittojen ja pituuden mittauksen lähtökohta on Ilvessalon (mt.) kuutioimistaulukoissaan soveltama puun juurenhaarojen määrittämä alin mahdollinen kaatokorkeus (ks. Ilvessalo 1965, s. 56, kuva 37). Edellä on kuvattu lyhyesti varsinaisten tukkipuutaulukoiden rakenne. Lisäksi on laadittu suppea erillistaulukko (taulukko 2), jota voidaan käyttää rungon tyvestä saatavan tukkiosan kuutiointiin silloin kun ko. tukkiosaa ei voida määrittää taulukoista edes ekstrapoloinnilla. Tätä erillistaulukkoa joudutaan siis käyttämään lähinnä rungon tyvestä saatavien lyhyiden tuk kien kuutiointiin. Tukkiosan (tukin) pituuden lisäksi on mitattava läpimitta noin 0.5 m pituuden puolivälin alapuolelta kuoren päältä 2 cm:n tasaavin luokin. Taulukot on laadittu suurehkojen runkomäärien kuutiointia varten. Ne on edelleen tarkoitettu maan eteläpuoliskon terveiden tukkipuukoivujen kuutiointiin. Vikaisuuksien vaikutus on otettava erikseen huomioon. Niiden arvioimisen mahdollisuuksia tarkastellaan suppeasti jäljempänä. Taulukoiden käyttö edellyttää edellä esitettyjen neljän tunnuksen (d, pituus, d— d 6 ja tukkiosan pituus) määrittämistä kuutioitavista rungoista. Määrittäminen olisi suoritettava mittauksiin perustuen, d-luokka yleensä kaikista rungoista, muut tunnukset sopivasti valituista koepuista. Rinnan korkeusläpimitta mitataan eteen sattuvalta puolelta, puidenluvussa 2 cm:n, koepuiden mittauksessa lisäksi kuten d 6 senttimetrin tasaavin luokin. Pituus mitataan metrin, tukkiosuus 0.5 metrin tasaavin luokin, jälkimmäisen luokkakeskusten ollessa täysiä ja puolia metrejä. Rungon tyviosaan rajoittu van lyhyehkön tukkiosan pituus voidaan ilmaista, kuten ATK-laskentaa käytettäessä, myös 3 dm:n kerrannaisina (31, 34, 37 . . . jne.). Jos taulukot eivät sisällä kuutioitavan rungon tunnusten mukaista luok kaa, voidaan nojautua inter- tai ekstrapolointiin, joka on edullisinta suorit taa graafisesti. Taulukoiden vastaista käyttöä ajatellen on syytä kirjoittaa inter- ja ekstrapoloinnilla saadut tulokset taulukkoihin ao. luokkien kohdalle. Lyhyehkö, tyviosaan rajoittuva tukkiosa saatetaan kuutioida myös taulukon 2 mukaisesti. Kuitupuuosa määritetään tällöin hakemalla ensin varsinaisista taulukoista, tarvittaessa Ilvessalon kuutioimistaulukoista, ko. rungon koko käyttöosa ja vähentämällä siitä taulukosta 2 saatu tukkiosa. Erillis taulukon käyttö on siten ilmeisesti hieman vaivalloista. KUUTIOIMISMENETELMÄN LUOTETTAVUUDESTA Tunnusten mittaamisesta Neljännen tunnuksen käyttöönotto antoi osaltaan aiheen kiinnittää huo miota myös mittausten käytännölliseen suorittamiseen ja siinä mahdollisesti syntyviin mittausvirheisiin. Mittausten suoritustapaa tarkastellaan erikseen jäljempänä. Seuraavassa käsitellään lyhyesti mittausvirheitä. Läpimittojen mittausta on tutkittu erityisesti viime aikoina hyvin run saasti. Metsäntutkimuslaitoksen metsänarvioimisen tutkimusosastossa kokeita ja vertailuja on suoritettu sekä valtakunnan metsien inventoinnin että pystypuiden mittausta käsittelevien tutkimusten yhteydessä. Tuloksia on kuitenkin julkaistu verraten vähän (esim. Vuokila 1960; Tii honen 1966 b, 1970). Leimikoiden pystymittauksen yhteydessä on tehty sekä mittaajien koulutuksessa että käytännön mittaustoiminnassa hyvin paljon vertailevia kokeita. Käytettävissä olevien tietojen mukaan eri tahoilla saadut tulokset ovat varsin yhdenmukaiset. Näyttää ilmeiseltä, että koulutetuilla mittaajilla jää läpimittojen mittauksessa syntyvä virhe ylei sesti ±1 cm:iin. Yksittäisiä 2—3 cm:n »kömmähdyksiä» on kyllä todettu, mutta niiden merkitys käytännön mittaustuloksiin jäänee varsin vähäiseksi. Molempien läpimittojen (d ja d 6) mittauksessa on kuitenkin vakuuttavasti ilmennyt koulutuksen välttämättömyys. Läpimittojen samoin kuin mui denkin tunnusten mittausvirheiden arvostelussa onkin aina otettava huo mioon mittaajien taito ja mittausolosuhteet. Todettakoon vielä, että koivu tukkipuilla oksat eivät yleensä vaikeuta läpimittojen mittausta. Haitallista puuston ylitiheyttä tuskin ilmenee. Mittausolosuhteet ovat siten tukki puukoivikoissa ainakin läpimittojen osalta usein edullisemmat kuin havu puilla, kuuseen verrattuna yleensä huomattavasti edullisemmat. Pituustunnusten mittauksen tarkastelussa lienee yleensä rajoituttu vain puun koko pituuteen, edelleen useimmiten havupuihin (esim. Tiihonen 1970). Tulosten mukaan on mittauksissa yleisesti onnistuttu hyvin. Toisaalta on ilmestynyt eräitä yllättäviä piirteitä. Seuraava lukusarja valaisee erään havupuiden pituuden mittausta koskeneen kokeen tuloksia. Mittaukset suoritettiin Padasjoella keväällä 1972. Kokeeseen sisältyi 25 koepuuta. Mittaajina oli 10 valtakunnan metsien inventoinnin ryhmänjohtajaa, joten mittausten lukumäärä oli yhteensä 250. Useimmat olivat tottuneita mit Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 22 79.1 taajia. Pituudet mitattiin »Suunto»-pituusmittarilla metrin tasaavin luokin. Mittauskohtien etäisyydet puun tyvestä määritettiin mittanauhalla. Koe mittausten jälkeen puut kaadettiin ja karsittiin,jonka jälkeen kunkin koe puun pituus mitattiin senttimetrin tarkkuudella. Pituudet vaihtelivat 14— 27 m:iin. Tulossarjan mukaan pääosa mittauksissa ilmenneistä eroista jää ±1 met riin. Aliarviointi on ollut hieman yleisempää kuin yliarviointi. Yleiskuva on ilmeisesti varsin myönteinen ja hyvin yhdenmukainen aikaisemmin suori tettujen vastaavanlaisten kokeiden tulosten kanssa (esim. Tiihonen 1970). Toisaalta havaitaan muutamia yksittäisiä suuria eroja. Ne ovat saat taneet aiheutua siitä, että pituus on luettu väärin, tähtäys tyveen on unoh tunut, on tehty laskuvirhe jne. Pituus on voitu lukea myös pituusmittarista väärältä asteikolta. Viimeksi mainittuun virhemahdollisuuteen on etenkin peruskoulutuksessa kiinnitettävä erityistä huomiota. Esitetty havupuiden tulossarja luonnehtinee ainakin verraten terävä latvaisten koivujen pituuden mittauksen tarkkuutta. Tarkasteltavaan tutki mukseen sisällytettiin myös koivujen pituuden mittausta koskenut koe. Mittauspaikka oli jälleen Padasjoki. Koepuita oli kaikkiaan 50. Koko pituu den lisäksi jokaisesta rungosta määritettiin kaksi tukkiosan pituutta. Vii meksi mainittujen päättymiskorkeuksia osoittivat runkoon tehdyt maali merkit, jotka sijaitsivat n. 10—15 m:n korkeudella ja 2 —3 m:n etäisyydellä toisistaan. Merkit, jotka tehtiin tikkaita, 5 m:n tankoa ja maalivasaraa apuna käyttäen, luonnehtivat siten yleisimpiä pituusmittarilla määritettäviä tukkiosan pituuksia. Kuten edellä on todettu, voidaan tukkiosan pituus määrittää B—lo8—10 mäin asti d6:n mittauksessa käytettävän kaulaimen var rella. Kahta erisuurta tukkiosan pituutta luonnehtivan merkin käyttö johtui yksinomaan siitä, että näin menetellen saatiin samoista koepuista kaksin kertainen määrä havaintoja. Kokeeseen osallistui yhdeksän mittaajaa, joista kolme toimii Enso- Gutzeit Osakeyhtiön metsäosaston leimikoiden pystymittauksissa. Muut olivat valtakunnan metsien inventoinnin ryhmänjohtajia ja mittausapulaisia. Kaikki olivat tehtävään hyvin perehtyneitä, joskin muutamat olivat mitan neet pituuksia käytännössä verraten vähän. Kaikki mittaukset tehtiin 0.5 m:n tasaavaa luokitusta soveltaen. Koe tapahtui muutoin samalla tavalla Ero todelliseen pituuteen verrattuna, m Unlerschied in bczug au/ die u-irkliche Länge, m 4 —3 —2 —1 ±0 +1 + 2 Erojen lukumäärä luokittain Anzahl der UiUerschiede nach Klasnen f 3 + 4 1 1 2 49 164 31 — 1 1 79.i Koivutukkipuiden kuutioimismenetelmä 23 kuin edellä tarkasteltu havupuita koskenut koe. Kaikki pituudet mitattiin siis lopuksi kaadetuista rungoista senttimetrin tarkkuudella. Kokeen suoritus jäi syksyyn, jolloin koivut ovat lehdettömiä. Mittaus aikana vallitsi kaunis, aurinkoinen sää. Voitiin kuitenkin otaksua, että lehdettömyys lisäsi tai ainakin suurensi jossain määrin puun koko pituuden mittauksessa syntyneitä eroja. Tulokset nähdään taulukosta 3. Taulukko 3. Koivun pituuden mittausta koskeneen kokeen tulokset. Padasjoki 1972. Tabelle 3. Ergebnisse der Probe über die Höhenmessung bei Birke, Padasjoki 1972. Taulukko 4. Koivun, tukkiosan pituuden mittausta koskeneen kokeen tuloksia. Tukkiosan pituus 12—15 m. Tabelle 4. Ergebnisse der Probe über die Längenmessung des Blochholzanteils an Birke. Länge des Blochholzanteils 12-15 m. Ero todelliseen pituuteen verrattuna, m — Differenz gegenüber der wirklichen Länge, m Mittaaja Person Nr. — 2.5 —2.0 —1.5 I —l.o —0.5 ±0 + 0.5 + 1.0 + 1.5 + 2.0 + 2.5 + 3.0 Erojen lukumäärä luokittain—Klassenireise Anzahl der Differenzen г 9 9 14 12 9 4 2 2 10 15 12 9 0 3 . 7 11 15 12 0 3 4 1 9 10 14 16 2 10 15 15 6 2 1 1 3 0.083 O.ioi 0.122 0.142 0.165 15 5 .131 0.229 .160 .192 .226 .262 7 3 .084 .213 .101 0.282 .256 .122 0.340 .301 .143 0.4 0 2 .350 .165 0.4 70 16 5 .131 .241 .161 .192 .226 .263 7 .213 .296 .256 .356 .301 .421 .352 .492 5 .131 .252 .163 .193 .228 .266 17 7 .215 .310 .259 .303 .355 9 .305 .373 .361 .442 .421 .516 5 .132 .264 .165 .197 .231 .269 18 7 .220 .325 .262 .309 .361 9 .314 .391 .372 .463 .433 .540 5 .136 .276 .16 » .200 .236 .272 19 7 .222 .339 .267 .314 .366 9 .321 .409 .381 .485 .442 .566 5 .137 .288 .168 .203 .237 .275 20 7 .222 .269 .317 .369 9 .273 .354 .326 .428 .386 .507 .451 .593 5 .138 .300 .168 .203 .238 .277 21 7 .222 .270 .319 .372 9 .274 .369 .329 .447 .388 .529 .454 .619 22 7 .223 .271 .320 .375 9 .274 .384 .330 .390 .458 11 .379 .466 .448 .552 .527 .646 23 7 .224 .271 .321 .377 9 .274 .400 .331 .392 .460 11 .383 .485 .453 .576 .530 .675 7 .224 .272 .322 .378 24 9 .275 .415 .332 .394 .461 11 .386 .504 .457 .601 .536 .704 9 .275 .431 .333 .396 .463 25 11 13 9 .387 .334 .523 .461 .519 .400 .625 .538 .468 .733 26 11 13 9 .391 .543 .466 .524 .404 .650 .545 .474 .7 62 27 11 13 .393 .563 .470 .532 .674 .554 .7 92 79.i Koivutukkipuiden kuutioimismenetelmä 39 KAPENEMISLUOKKA, 2 cm — Ausbauchungsklasse, 2 cm d-luokka, cm — d-Klause, cm Pituus- Tukkiosan 29 31 33 35 37 39 luokka, m pituus, m Höhen- Länge des Tukkiosa (1) ja rungon koko kävttöosa (2), k-n l 3 kuorineen/runko klaue?, m Blochholz- anteils, m Blochholzaniei (1) und der ganze Nutzteil des Stammes 2), Fm. mit Rinde!Stamm 1 2 ~ 7- 1 2 1 2 1 2 1 2 5 О.зоз 0.344 0.392 0.443 0.502 0.564 15 7 .407 .463 .527 .598 .676 .761 9 .481 0.544 .549 0.622 .625 0.708 .710 0.805 .804 0.913 .904 1.026 5 .303 .346 .393 .445 .503 .565 lii 7 .409 .465 .528 .600 .679 .762 9 .485 .570 .556 .654 .632 .745 .716 .847 .810 .960 .911 1.076 7 .411 .471 .532 .602 .685 .765 17 9 .486 .562 .641 .725 .818 .918 11 .545 .597 .627 .686 .714 .782 .809 .888 .916 1.006 1.026 1.126 7 .415 .478 .543 .612 .695 .770 18 9 .500 .575 .655 .741 .838 .929 11 .562 .625 .647 .719 .737 .821 .835 .929 .948 1.056 1.050 1.176 7 .421 .486 .550 .620 .702 .776 19 9 .512 .588 .669 .758 .852 .945 11 .575 .655 .665 .753 .758 .859 .858 .972 .967 1.096(1.071 1.216 7 .427 .489 .556 .628 .704 .780 20 9 .521 .595 .680 .768 .858 .956 11 .590 .686 .680 .788 .775 .898 .876 1.016 .979 1.136 1.088 1.266 9 .526 .602 .685 .773 .865 .962 21 11 .600 .689 .785 .884 .989 1.100 13 .658 .717 .753 .822 .858 .937 .966 1.056 1.084 1.186 1.203 1.316 9 .532 .608 .690 .776 .867 .970 22 11 .610 .698 .794 .891 .995 1.110 13 .671 .748 .768 .857 .870 .976 .981 1.096 1.097 1.226 1.222 1.376 9 .534 .612 .695 .778 .870 .974 23 11 .614 .700 .797 .893 .998 1.118 13 .679 .781 .777 .894 .882 1.016 .990 1.136 1.106 1.276 1.235 1.426 11 .619 .706 .800 .898 1.004 1.125 24 13 .691 .789 .894 1.003 1.121 1.253 15 .746 .815 .850 .931 .966 1.056 1.084 1.186 1.211 1.326 1.330 1.476 11 .623 .710 .803 .904 1.008 1.131 25 13 .699 .796 .905 1.015 1.129 1.270 15 .759 .849 .865 .969 .979 1.096 1.102 1.236 1.227 1.376 1.357 1.536 11 .631 .717 .806 .915 1.015 1.140 2(i 13 .710 .807 .916 1.031 1.150 1.275 15 .776 .884 .882 1.006 1.003 1.146 1.126 1.286 1.257 1.436 1.392 1.596 13 .724 .820 .928 1.045 1.174 1.310 27 15 .792 .919 .901 1.021 1.149 1.287 1.436 17 .980 1.046 1.095 1.186 1.230 1.336 1.376 1.496 1.526 1.656 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 40 79.i TUKKIPUUTAULUKOT Koivu d-luokka, cm Pituus- Tukkiosan 19 21 23 25 27 luokka, m pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2), k-m 8 kuorineen/runko 1 2 1 2 1 2 1 o 1 2 15 3 5 7 0.082 0.214 0.100 .155 0.266 0.120 .187 .246 0.323 0.141 .220 .290 0.384 0.164 .256 .338 0.4 50 16 3 5 7 .083 .225 .101 .157 .278 .121 .188 .247 .337 .142 .222 .292 .401 .165 .258 .341 .470 17 3 5 7 .084 .235 .102 .158 .291 .121 .188 .247 .352 .142 .222 .293 .419 .165 .259 .342 .492 18 3 5 7 .084 .245 .102 .158 .207 .304 .122 .189 .249 .368 .143 .224 .295 .439 .166 .260 .345 .515 19 5 7 9 .159 .208 .317 .191 .251 .302 .385 .227 .299 .361 .459 .264 .350 .423 .538 20 5 7 9 .159 .209 .330 .193 .254 .305 .402 .228 .302 .364 .479 .266 .353 .428 .562 21 5 7 9 .159 .210 .343 .195 .256 .309 .419 .229 .304 .368 .4 99 .269 .358 .434 .586 22 5 7 9 .160 .211 .356 .196 .257 .311 .436 .231 .306 .371 .520 .270 .359 .438 .612 23 7 9 11 .212 .370 .258 .312 .453 .308 .373 .430 .542 .360 .441 .507 .638 24 7 9 11 .213 .381 .259 .315 .470 .310 .377 .436 .564 .363 .444 .513 .664 25 7 9 11 .214 .398 .260 .317 .487 .311 .380 .440 .586 .364 .447 .519 .690 26 7 9 11 .260 .318 .504 .312 .382 .443 .608 .365 .448 .523 .716 27 9 11 13 .384 .447 .501 .630 .451 .525 .589 .743 79.i Koivutukkipuiden kuutioimismenetelmä 41 6 15132—73 KAPENEMISLUOKKA, 3 cm Pituus- luokka, m Tukkiosan pituus, m d-luokka, cm 29 31 33 35 37 39 Tukkiosa (1) ja rungon koko käyttöosa (2), k-ir 3 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 1 2 5 0.297 0.338 0.385 0.437 0.496 0.561 15 7 .393 .449 .512 .582 .655 .749 9 .463 0.523 .531 0.6OO .605 0.684 .690 0.7 80 .784 0.889 .887 1.006 5 .298 .342 .388 .440 .500 .563 16 7 .395 .455 .516 .590 .660 .750 9 .470 .547 .538 .630 .615 .719 .700 .819 .793 .930 .898 1.046 5 .299 .343 .388 .442 .502 .565 17 7 .397 .456 .520 .591 .663 .750 9 .474 .572 .544 .660 .623 .754 .705 .857 .798 .971 .901 1.096 7 .400 .460 .525 .594 .669 .750 18 9 .482 .553 .630 .714 .809 .905 11 .538 .598 .621 .690 .709 .790 .805 .897 .912 1.016 1.018 1.136 7 .405 .467 .533 .602 .676 .753 19 9 .490 .565 .645 .730 .822 .916 11 .555 .626 .639 .722 .731 .826 .828 .936 .932 1.056 1.038 1.176 7 .412 .477 .545 .613 .689 .765 20 9 .500 .581 .663 .750 .841 .935 11 .568 .654 .659 .754 .750 .862 .852 .976 .955 1.096 1.068 1.226 7 .419 .485 .552 .620 .695 .775 21 9 .508 .589 .670 .759 .847 .943 11 .577 .682 .671 .786 .765 .898 .865 1.016 .967 1.136 1.083 1.276 9 .511 .593 .672 .762 .850 .944 22 H .587 .678 .771 .871 .976 1.094 13 .644 .712 .743 .818 .848 .934 .958 1.056 1.070 1.186 1.199 1.326 9 .513 .594 .673 .762 .850 .945 23 11 .592 .683 .776 .876 .982 1.096 13 .651 .742 .751 .852 .856 .970 .966 1.096 1.085 1.226 1.205 1.366 9 .516 .596 .674 .762 .850 .945 24 11 .598 .688 .780 .880 .987 1.099 13 .663 .772 .760 .886 .866 1.006 .978 1.136 1.094 1.276 1.218 1.416 9 .519 .596 .675 .762 .850 .945 25 11 .602 .691 .781 .884 .989 1.100 13 .670 .803 .768 .922 .870 1.046 .986 1.186 1.101 1.326 1.227 1.476 11 .603 .692 .783 .890 .990 1.102 26 13 .676 .775 .878 .997 1.109 1.237 15 .735 .835 .843 .958 .955 1.086 1.086 1.236 1.208 1.376 1.348 1.536 13 .686 .788 .889 1.006 1.124 1.249 27 15 .750 .867 .861 .972 1.100 1.230 1.366 17 .917 .996 1.036 1.126 1.173 1.276 1.311 1.426 1.456 1.586 42 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.i TUKKIPUUTAULUKOT Koivu d-luokka, cm Pituus- Tukkiosan 21 1 23 25 27 29 luokka, m pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2 , k-m 3 kuorineen/runko 1 2 1 1 « ! 1 2 1 2 1 2 15 5 7 9 0.151 0.249 0.184 .238 0.3 05 0.217 .282 0.365 0.254 .331 .383 .430 0.294 .384 .450 0.501 16 5 7 9 .152 .260 .185 .238 .318 .218 .284 .381 .254 .333 .388 .449 .295 .385 .456 .524 17 5 7 9 .153 .271 .185 .239 .332 .219 .285 .333 .398 .255 .335 .393 .469 .296 .386 .461 .548 18 5 7 9 .154 .283 .186 .240 .347 .221 .287 .337 .416 .256 .337 .399 .490 .298 .389 .466 .572 19 5 7 9 .155 .294 .187 .242 .361 .223 .290 .346 .434 .259 .340 .407 .511 .300 .394 .474 .597 20 5 7 9 .155 .306 .188 .245 .376 .223 .292 .349 .452 .261 .342 .411 .533 .303 .398 .483 .623 21 5 7 9 .155 .318 .189 .246 .391 .224 .293 .351 .470 .263 .345 .416 .556 .307 .402 .490 .649 22 7 .247 .295 .407 .294 .354 .489 .346 .418 .480 .579 .405 .492 .562 .676 23 _ 1 9 11 .247 .297 .422 .295 .356 .407 .508 .348 .420 .485 .602 .407 .493 .567 .703 24 7 9 11 .248 .298 .436 .296 .359 .411 .528 .350 .424 .489 .626 .410 .495 .571 .731 25 9 11 13 .299 .451 .360 .415 .547 .426 .493 .649 .496 .574 .636 .759 2(3 9 11 13 .300 .4 66 .361 .417 .567 .428 .495 .673 .498 .576 .643 .788 27 9 11 13 .362 .420 .587 .429 .497 .698 .499 .580 .650 .817 79.i Koivutukkipuiden kuutioimismenetelmä 43 KAPENEMISLUOKKA, 4 cm d-luokka, cm 31 33 35 37 39 Pituus- Tukkiosan luokka, m pituus, in Tukkiosa (1) ja rungon koko käyttöosa (2), k-m 3 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 5 0.336 0.381 0.434 0.491 0.5 5 5 15 7 .441 .502 .572 .646 .731 9 .515 0.5 7 7 .588 0.660 .671 0.755 .764 0.859 .864 0.969 5 .338 .383 .437 .496 .556 16 7 .444 .507 .577 .650 .733 9 .522 .605 .599 .693 .681 .791 .773 .899 .872 1.0X6 5 .34« .384 .439 .498 .506 17 7 .446 .511 .581 .654 ■ 73ö 9 .529 .633 .605 .726 .691 .827 .781 .939 .877 1.036 7 .449 .515 .584 .657 .737 18 9 .536 .662 .613 .699 .789 .883 11 .684 .760 .778 .864 .880 .979 .985 1.096 7 .454 .520 .588 .661 .740 19 9 .546 .691 .626 .709 .798 .891 11 .704 .793 .799 .901 .901 1.016 1.007 1.136 7 .462 .527 .594 .670 .745 20 9 .557 .721 .639 .722 .814 .905 11 .723 .826 .820 .938 .923 1.056 1.027 1.176 7 .467 .533 .600 .675 .751 21 9 .563 .750 .647 .729 .822 .915 11 .735 .859 .832 .976 .935 1.096 1.045 1.226 9 .567 .650 .731 .824 .918 22 11 .648 .780 .742 .836 .944 1.053 13 .811 .893 .921 1.016 1.031 1.136 1.155 1.276 9 .569 .650 .732 .826 .920 23 11 .653 .811 .746 .840 .948 1.057 13 .817 .926 .926 1.046 1.037 1.176 1.162 1.316 9 .570 .651 .734 .828 .920 24 11 .657 .842 .748 .845 .950 1.062 13 .825 .960 .937 1.086 1.048 1.226 1.171 1.366 11 .661 .750 .848 .951 1.065 25 13 .732 .875 .831 .943 1.057 1.178 15 .898 .996 1.016 1.126 1.142 1.266 1.275 1.416 11 .663 .751 .852 .953 1.069 2(i 13 .738 .909 .840 .953 1.065 1.185 15 .913 1.036 1.036 1.176 1.158 1.316 1.289 1.466 11 .665 .753 .858 .957 1.070 27 13 .749 .943 .853 .964 1.081 1.200 15 .931 1.076 1.053 1.216 1.180 1.366 1.318 1.526 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.i 44 TUKKIPUUTAULUKOT Koivu d-luokka, cm Pituus- Tukkiosan 21 23 25 27 29 luokka, m pituus, m Tukkiosa (X) ja rungon koko käyttöosa (2), k-m s kuorineen/runko 1 2 1 2 1 2 1 2 1 2 15 5 7 9 0.149 0.233 0.182 0.287 0.215 .275 0.346 0.250 .325 0.410 0.291 .378 .443 0.479 16 5 7 9 .150 .243 .183 .299 .216 .278 .361 .251 .327 .427 .291 .380 .449 .500 17 5 7 9 .151 .253 .183 .312 .217 .280 .376 .252 .328 .385 .446 .292 .381 .453 .522 18 5 7 9 .152 .263 .184 .325 .217 .281 .392 .253 .329 .387 .465 .293 .383 .457 .544 19 5 7 9 .152 .273 .184 .232 .338 .218 .282 .408 .255 .330 .389 .484 .295 .386 .463 .568 20 5 7 9 .153 .283 .185 .234 .351 .219 .282 .334 .424 .256 .331 .392 .504 .296 .388 .470 .592 21 5 7 9 .153 .293 .186 .236 .364 .220 .283 .336 .440 .257 .332 .396 .524 .297 .390 .475 .616 22 5 7 9 .186 .237 .377 .220 .284 .338 .457 .258 .334 .400 .545 .298 .392 .478 .641 23 7 9 11 .237 .390 .285 .341 .474 .335 .403 .460 .566 .393 .480 .542 .665 24 7 9 11 .237 .403 .285 .342 .492 .336 .405 .462 .588 .394 .481 .545 .690 25 2 11 .238 .416 .286 .344 .509 .338 .407 .468 .609 .395 .482 .547 .716 26 9 11 13 .344 .395 .527 .408 .470 .521 .630 .483 .550 .616 .742 27 9 11 13 .345 .397 .544 .408 .472 .527 .651 .483 .555 .625 .767 79.i Koivutukkipuiden kuutioimismenetelmä 45 KAPENEMISLUOKKA, 5 cm d-luokka, cm 31 33 35 37 39 41 Pituus- Tukkiosan luokka, m pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2), k-n l 8 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 1 2 5 0.334 0.380 0.431 0.488 0.550 0.618 15 7 .434 .495 .564 .640 .722 .815 9 .504 0.553 .576 0.634 .657 0.723 .747 0.824 .846 0.934 .944 1.044 5 .335 .381 .434 .493 .551 .621 16 7 .437 .500 .569 .643 .723 .818 9 .513 .579 .588 .665 .668 .759 .760 .864 .854 .976 .962 1.091 5 .335 .381 .436 .495 .552 .621 17 7 .440 .504 .572 .645 .723 .818 9 .519 .606 .595 .696 .677 .794 .768 .902 .861 1.016 .969 1.131 5 .345 .382 .439 .498 .554 .623 18 7 .442 .506 .574 .646 .724 .818 9 .523 .632 .600 .728 .687 .828 .775 .939 .866 1.056 .972 1.176 7 .444 .509 .578 .648 .726 .818 19 9 .529 .609 .693 .778 .870 .974 11 .593 .660 .681 .759 .772 .863 .873 .976 .980 1.096 1.086 1.216 7 .446 .512 .580 .650 .727 .818 20 9 .536 .616 .699 .781 .875 .975 11 .625 .687 .694 .790 .788 .898 .881 1.006 .994 1.136 1.102 1.261 7 .448 .515 .582 .652 .728 .818 21 9 .540 .622 .703 .785 .879 .978 11 .614 .714 .706 .821 .799 .932 .892 1.046 1.006 1.176 1.118 1.311 9 .545 .625 .706 .790 .883 .980 22 11 .620 .713 .807 .905 1.012 1.126 13 .677 .742 .779 .852 .883 .967 .991 1.086 1.108 1.216 1.235 1.356 9 .549 .627 .709 .792 .885 .984 23 11 .626 .719 .813 .914 1.018 1.133 13 .688 .770 .788 .883 .897 1.006 1.005 1.126 1.120 1.256 1.247 1.401 9 .551 .629 .712 .795 .887 .987 24 11 .630 .722 .818 .918 1.023 1.139 13 .696 .799 .796 .915 .905 1.036 1.014 1.166 1.131 1.306 1.258 1.456 9 .553 .630 .713 .797 .888 .990 25 11 .633 .724 .820 .921 1.025 1.142 13 .703 .829 .803 .949 .910 1.076 1.021 1.206 1.138 1.346 1.269 1.511 11 .636 .726 .823 .923 1.027 1.144 26 13 .709 .810 .916 1.030 1.144 1.278 15 .767 .860 .874 .982 .993 1.116 1.116 1.256 1.239 1.396 1.385 1.561 11 .641 .728 .825 .926 1.030 1.148 27 13 .717 .815 .928 1.038 1.155 1.285 15 .780 .891 .889 1.016 1.008 1.156 1.130 1.296 1.260 1.446 1.407 1.616 46 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 TUKKIPUUTAULUKOT Koivu d-luokka, cm Pituus- Tukkiosan 23 25 27 29 31 luokka, m pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2), k-m 3 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 15 3 5 7 0.120 .177 0.27O 0.141 .211 .266 0.327 0.165 .246 .315 0.3 90 0.191 .287 .368 0.459 0.218 .332 .426 0.532 lii 3 5 7 .120 .179 .280 .142 .212 .269 .340 .166 .247 .317 .406 .193 .288 .371 .479 .222 .332 .429 .557 17 5 7 9 .180 .291 .213 .270 .354 .248 .318 .423 .288 .373 .436 .500 .332 .430 .505 .581 18 5 7 9 .181 .303 .214 .270 .368 .249 .318 .440 .289 .375 .438 .520 .333 .432 .510 .605 19 5 7 9 .181 .314 .214 .270 .382 .250 .318 .372 .458 .290 .375 .440 .541 .333 .433 .513 .630 20 5 7 9 .214 .270 .397 .250 .319 .375 .476 .291 .376 .443 .563 .334 .434 .517 .656 21 5 7 9 .214 .271 .411 .250 .320 .377 .493 .293 .377 .447 .585 .334 .435 .520 .681 22 7 9 И .271 .426 .320 .380 .511 .378 .450 .510 .606 .436 .522 .592 .705 23 7 9 11 .271 .320 .441 .321 .382 .434 .530 .379 .452 .514 .628 .437 .525 .595 .7 30 24 7 9 11 .271 .321 .456 .321 .383 .436 .549 .379 .453 .516 .649 .438 .526 .598 .756 25 7 9 11 .272 .322 .471 .322 .384 .438 .567 .379 .453 .518 .671 .439 .526 .601 .783 26 9 11 13 .323 .486 .384 .440 .585 .453 .519 .575 .693 .526 .603 .670 .810 27 9 11 13 .323 .500 .385 .442 .603 .453 .520 .582 .715 .526 .605 .677 .836 79.i Koivutukkipuiden kuutioknismenetelmä 47 KAPENEMISLUOKKA, 6 cm d-Iuokka, cm Pituus- Tukkiosan 33 35 37 39 41 43 luokka, m pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2), k-n i 3 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 1 2 5 0.376 0.428 0.483 0.542 0.602 0.667 15 7 .485 .553 .627 .705 .786 .865 9 .558 0.6O9 .638 0.697 .723 0.7 92 .816 0.894 .909 0.996 1.012 1.106 5 .377 .430 .487 .545 .606 .671 16 7 ■ •490 .558 .631 .709 .788 .867 9 .562 .637 .649 .728 .735 .827 .827 .931 .920 1.041 1.025 1.156 5 .378 .431 .491 .547 .608 .673 17 7 .493 .560 .633 .710 .789 .869 9 .575 .666 .657 .760 .7 45 .863 .835 .969 .931 1.081 1.033 1.201 5 .378 .432 .492 .547 .610 .673 18 7 .495 .562 .634 .711 .790 .870 9 .583 .696 .662 .793 .750 .899 .841 1.006 .936 1.126 1.039 1.251 7 .496 .563 .635 .711 .790 .870 19 9 .588 .667 .753 .843 .939 1.041 11 .653 .726 .742 .826 .838 .934 .937 1.046 1.044 1.166 1.155 1.291 7 .498 .564 .635 .711 .790 .870 20 9 .593 .674 .756 .846 .944 1.043 11 .666 .755 .758 .860 .851 .968 .953 1.086 1.065 1.216 1.175 1.341 7 .500 .566 .636 .711 .790 .870 21 9 .597 .678 .762 .850 .948 1.047 11 .677 .784 .769 .893 .866 1.006 .965 1.126 1.078 1.256 1.189 1.386 9 .600 .680 .768 .853 .951 1.051 22 11 .683 .776 .876 .975 1.086 1.201 13 .744 .812 .847 .925 .956 1.046 1.065 1.166 1.187 1.301 1.315 1.441 9 .602 .682 .770 .856 .952 1.053 23 11 .688 .781 .880 .981 1.093 1.209 13 .7 54 .840 .856 .956 .968 1.086 1.077 1.206 1.201 1.346 1.329 1.491 9 .605 .685 .771 .859 .953 1.055 24 11 .690 .785 .885 .986 1.097 1.218 13 .759 .868 .866 .988 .976 1.116 1.089 1.246 1.212 1.396 1.347 1.551 11 .691 .787 .885 .990 1.100 1.220 25 13 .763 .871 .979 1.097 1.221 1.355 15 .821 .898 .937 1.026 1.053 1.156 1.182 1.296 1.317 1.446 1.462 1.606 11 .692 .789 .885 .993 1.103 1.223 26 13 .769 .877 .984 1.107 1.227 1.363 15 .831 .930 .950 1.066 1.065 1.196 1.198 1.346 1.330 1.496 1.475 1.661 11 .694 .790 .886 .995 1.105 1.225 27 13 .775 .883 .995 1.114 1.235 1.374 15 .843 .962 .959 1.096 1.080 1.236 1.211 1.386 1.349 1.546 1.496 1.716 48 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 TUKKIPUUTAULUKOT Koivu Pituus- luokka, m Tukkiosan pituus, m d-luokka, cm 27 29 31 33 Tukkiosa (1) ja rangon koko käyttöosa (2), k-m 3 kuorineen/runko 1 2 1 2 1 2 1 2 5 0.242 0.283 0.326 0.3 70 15 7 .302 0.369 .356 0.438 .413 .471 9 .470 0.510 .538 0.585 5 .242 .283 .326 .370 ie 7 .303 .384 .358 .456 .415 .473 9 .478 .532 .547 .612 5 .243 .283 .326 .371 17 7 .303 .400 .359 .474 .415 .475 9 .482 .555 .553 .639 5 .243 .283 .326 .371 18 7 .304 .416 .359 .493 .415 .476 9 .485 .577 .557 .666 5 .243 .283 .326 .372 19 7 .305 .432 .359 .512 .415 .477 9 .487 .600 .561 .693 5 .243 .284 .326 .373 20 7 .306 .448 .359 .532 .416 .478 9 .490 .623 .566 .720 6 .244 .285 .327 .374 21 7 .307 .464 .360 .552 .417 .480 9 .494 .645 .570 .746 5 .244 .286 .328 .374 22 7 .307 .361 .418 .480 9 .360 .479 .430 .571 .497 .667 .571 .771 5 .244 .286 .328 .374 23 7 .307 .362 .419 .480 9 .360 .495 .430 .589 .499 .689 .572 .796 7 .307 .362 .419 .480 24 9 .360 .511 .430 .499 .572 11 .483 .608 .562 .711 .648 .821 7 .307 .362 .420 .480 25 9 .360 .430 .500 .572 11 .408 .526 .485 .627 .565 .734 .650 .847 9 .360 .430 .500 .572 26 11 .410 .541 .488 .568 .654 13 .540 .646 .630 .757 .725 .874 9 .360 .430 .500 .572 27 11 .411 .556 .489 .572 .657 13 .543 .664 .636 .781 .733 .902 Koivutukkipuiden kuutioimismenetelmä 49 79.i 7 15132—73 KAPENEMISLUOKKA, 7 cm d-luokka, cm 35 37 39 41 43 45 Pituus- j Tukkiosan luokka, m j pituus, m Tukkiosa (1) ja rungon koko käyttöosa (2), k-n l 3 kuorineen/runko 1 2 1 -2 1 2 1 2 1 2 1 2 5 0.4 20 0.476 0.534 0.590 0.653 0.715 15 7 .537 .61« .680 .760 .840 .925 9 .616 0.670 .701 0.764 .792 0.864 .883 0.966 .978 1.066 1.077 1.176 5 .422 .478 .535 .590 .654 .716 10 ! 7 .540 .612 .681 .7 60 .840 .925 9 .626 .701 .711 .7 98 .802 .900 .892 1.004 .985 1.111 1.086 1.226 5 .424 .481 .535 .590 .656 .717 17 ! 7 .041 .612 .682 .7 60 .840 .925 9 .632 .7 32 .717 .832 .806 .936 .896 1.042 .990 1.156 1.095 1.281 5 .424 .481 .535 .590 .656 .717 lis ! 7 .542 .612 .682 .7 60 .841 .925 9 .635 .762 .720 .865 .809 .973 .901 1.086 .995 1.206 1.101 1.331 7 .542 .612 .682 .760 .841 .925 19 9 .640 .724 .813 .904 1.000 1.104 11 .710 .792 .803 .897 .899 1.006 1.005 1.126 1.111 1.246 1.226 1.376 7 .543 .612 .682 .760 .842 .925 20 9 .646 .727 .816 .907 1.005 1.106 11 .725 .823 .817 .929 .918 1.046 1.022 1.166 1.130 1.291 1.247 1.426 7 .544 .612 .683 .761 .843 .925 21 : 9 .650 .730 .820 .912 1.010 1.110 11 .736 .853 .826 .961 .929 1.086 1.034 1.206 1.144 1.336 1.260 1.476 7 .54 4 .612 .683 .762 .843 .925 22 9 .651 .732 .822 .917 1.015 1.114 11 .740 .882 .831 .996 .935 1.126 1.042 1.251 1.153 1.38611.268 1.526 9 .653 .734 .823 .919 1.017 1.115 23 11 .743 .836 .940 1.048 1.160 1.275 13 .815 .911 .917 1.026 1.031 1.156 1.154 1.296 1.277 1.436 1.401 1.576 9 .653 .736 .823 .920 1.018 1.115 24 i 11 .745 .839 .943 1.053 1.164 1.278 13 .820 .941 .922 1.066 1.039 1.196 1.163 1.336 1.285 1.481 1.414 1.631 11 .747 .841 .945 1.056 1.167 1.280 25 ! 13 .826 .929 1.044 1.168 1.293 [1.422 15 .885 .970 1.000 1.096 1.126 1.236 1.257 1.381 1.392 1.531 1.532 1.686 11 .749 .844 .946 1.058 1.169 1.283 20 .j 13 .833 .938 1.052 1.176 1.304 1.438 15 .900 1.006 1.016 1.136 1.140 1.276 1.277 1.431 1.414 1.586 1.559 1.751 11 .750 .847 .947 1.062 1.173 1.285 27 13 .839 .945 1.062 1.188 1.319 1.455 15 .911 1.036 1.032 1.176 1.154 1.316 1.292 1.476 1.435 1.641 1.583 1.811 50 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.i TUKKIPUUTAULUKOT Koivu d-luokka, cm Pituus- Tukkiosan 25 >7 29 31 33 luokka, m pituus, in Tukkiosî (1) ja rungon koko käyttöosa (2). k-m 3 kuorineen/runko 1 2 1 2 1 2 1 2 1 2 5 0.19f> 0.290 0.235 0.275 0.319 0.362 15 7 .289 0.349 .343 0.418 .399 0.488 .456 0.561 5 .19« .300 .235 .275 .320 .363 ll> 7 .290 .363 .343 .434 .400 .508 .458 .586 5 .19« .311 .235 .275 .320 .363 17 7 .291 .377 .343 .450 .400 .529 .459 .611 5 .19« .321 .235 .275 .320 .363 18 7 .291 .391 .343 .467 .400 .549 .460 .636 5 .196 .332 .235 .275 .320 .363 19 7 .291 .406 .343 .485 .400 .569 .460 .661 5 .190 .344 .235 .275 .320 .364 20 7 .292 .420 .344 .502 .401 .590 .460 .685 5 .196 .355 .235 .276 .320 .364 21 7 9 5 .293 .23.» .434 .345 .400 .276 .519 .401 .475 .320 .610 .460 .364 .708 22 7 9 5 .293 .235 .447 .345 .400 .276 .536 .401 .4 75 .320 .630 .460 .364 .731 23 7 .293 .346 .401 .4 60 .754 9 .338 .460 .400 .552 .475 .650 5 .235 .276 .320 .364 24 7 .293 .346 .401 .460 9 .338 .473 .401 .568 .475 .669 .540 .7 76 7 .293 .346 .401 .460 25 9 .338 .486 .401 .475 .541 11 .455 .583 .534 .688 .616 .7 99 7 .293 .346 .401 .460 26 9 .338 .498 .402 .475 .542 11 .456 .599 .535 .707 .620 .822 9 .338 .510 .402 .475 .543 27 11 13 .457 .614 .537 .596 .727 .622 .690 .846 79.' Koivutukkipuiden kuutioimismenetelrnä 51 KAPENEMISLUOKKA, 8 cm d-liiokka, cm Pituus- 1 35 37 39 41 43 45 Tukkiosan ! luokka. m pituus, m I ïukkiosa (1) ja rungon koko käyttöosa (2), k-m B kuorineen/runko ! 1 2 1 2 l 2 1 1 2 1 2 1 2 5 i 0.412 0.46(5 0.524 0.581 0.638 0.7 0 2 15 7 .521 .590 .660 .7 36 .815 .900 9 .59 t 0.6 + 4 .678 0.736 .765 0.833 .854 0.931 .951 1.034 1.047 1.1 41 5 .414 .468 .524 .581 .639 .702 lu 7 .523 .590 .660 .738 .815 .900 9 : .602 .673 .683 .768 .774 .867 .862 .967 .955 1.071 1.051 1.181 5 .415 .470 .524 .581 .640 .702 17 7 .524 .590 .661 .739 .815 .900 9 .610 .701 .690 .799 .780 .901 .866 1.004 .958 1.111 1.056 1.226 5 .415 .470 .524 .581 .640 .702 18 7 1 .524 .590 .662 .740 .815 .900 9 .613 .729 .695 .829 .7 82 .935 .868 1.042 .960 1.156 1.059 1.276 7 .524 .590 .662 .740 .815 .900 19 9 .616 .697 .786 .870 .962 1.062 11 .682 .757 .7 71 .859 .868 .969 .968 1.081 1.070 1.196 1.181 1.321 7 .524 .591 .663 .740 .815 .900 20 9 .620 .699 .789 .873 .966 1.068 11 .692 .784 .784 .889 .881 1.006 .981 1.116 1.085 1.241 1.202 1.371 7 .525 .592 .663 .741 .815 .900 21 9 .623 .703 .791 .876 .970 1.071 1 1 .702 .811 .7 94 .920 .890 1.036 .995 1.156 1.101 1.281 1.213 1.416 7 .526 .592 .664 .741 .815 .900 22 9 .624 .705 .792 .879 .975 1.073 11 , .706 .838 .800 .951 .894 1.066 1.002 1.201 1.111 1.331 1.223 1.466 1 .526 .592 .665 .742 .815 .900 23 9 .625 .707 .792 .881 .978 1.075 11 .709 .865 .803 .982 .898 1.106 1.008 1.241 1.117 1.376 1.230 1.516 9 .626 .708 .792 .883 .980 1.075 24 11 .710 .805 .900 1.009 1.120 1.235 13 .776 .892 .886 1.016 .993 1.136 1.114 1.276 1.238 1.421 1.365 1.571 9 .626 .708 .792 .884 .980 1.075 25 11 .710 .805 .900 1.010 1.123 1.240 13 .781 .918 .889 1.046 .998 1.176 1.118 1.321 1.243 1.471 1.369 1.621 11 .710 .806 .901 1.012 1.125 1.241 2 U 13 1 .785 .892 1.003 1.124 1.251 1.381 15 .848 .944 .964 1.076 1.089 1.216 1.217 1.361 1.355 1.516 1.496 1.676 11 .711 .807 .901 1.013 1.128 1.242 27 13 : .790 .895 1.005 1.137 1.264 1.391 15 ; .856 .971 .973 1.106 1.095 1.246 1.234 1.406 1.373 1.566 1.513 1.726 52 Juhani Nousiainen, Juha Puranen ja Paavo Tiihonen 79.1 TUKKIPUUTAULUKOT Koivu 7 29 31 33 luokka. m pituus, in Tukkinen (1) ja rungon koko käyttöosa (2). k-m* kuorineen/runko 1 2 i 1 2 1 o 1 2 1 - 3 0.135 0.159 0.187 0.215 0.243 15 5 .189 0.279 .220 0.329 .205 .310 .350 7 .330 0.396 .385 0.4 00 .4 4 3 0.537 3 .135 .159 .187 i .215 .244 16 5 .189 .280 ! .220 .341 .265 .310 .350 7 3 .135 .159 .330 .187 411 .385 .215 .484 .443 .244 .560 17 5 .189 .289 .220 .265 ; .310 .350 7 3 .13.5 .277 .159 .354 .330 .187 420 1 .385 .215 .503 .443 .244 .583 18 5 .189 .299 ; .227 i .200 .310 .350 7 .277 .30 7 j .330 441 .38.') .521 .443 .000 5 .189 .308 .227 .207 .310 .350 10 7 .278 .380 ! .330 .385 .443 9 .380 457 .445 .539 .510 .029 5 .189 .317 j .227 .207 .310 .350 20 7 .27 8 .392 ! .330 .38'» .444 9 .380 472 .447 .558 .510 .050 5 .1 89 .326 i .227 .207 .310 . 3 5 0 21 7 .278 .403 .330 .380 .444 9 .380 480 .449 .570 .510 .071 5 .189 .335 .227 .207 .311 .350 22 7 .278 .41 1 .330 .380 .444 9 .381 500 .449 .593 .518 .092 5 .227 .208 1 .311 .350 23 7 9 5 .279 .227 .4 25 .331 1 .381 .208 515 .380 .450 .311 .010 .444 .519 .350 .71. 24 7 .279 .435 .331 .380 .444 9 .382 528 .450 .02 7 .520 .731 9 .382 .450 .520 25 11 13 9 .420 .382 540 1 .503 .553 .450 .043 .585 .044 .520 .751 26 11 13 9 .420 552 .503 1 .554 .450 .058 .585 .04 7 .520 .771 27 11 13 .503 .555 .07 4 .580 .049 .7 91 79.i Koivutukkipuiden kuutioimismenetelmä 53 KAPENEMISLTJOKKA, 9 sm 6.5) that the nitrogen present as ammonium ions becomes free ammonia. When the uptake, retention and leaching of nitrogen given as urea are mentioned in this study, reference is really made to ammonium ions, because urea is hydrolysed rather quickly in ground covered by vegetation (e.g. Gibson 1930, Roberge&Knowles 1966). Similarly, volatilization of nitrogen refers to volatilization of ammonia. Volatilization of some of the ammonia produced by the hydrolysis of urea has been suggested as one possible reason for the weaker effect of urea than of calcium ammonium saltpeter. This assumption is based closely on the results of laboratory and field experiments carried out for instance in Sweden and Norway (e.g. Nömmik 1967, Over r e i n 1968, 1969). In the case of peatlands, it has been stressed that the behaviour of urea in peat is not clearly known and thus further research has been considered necessary (Paavilainen 1972 a). According to the studies carried out upto now, the time of fertilizer application on deep peat is of small practical significance while the ground is not frozen (Paarlahti 1967, Karsisto 1967, Paavilainen 1969). Application of easily soluble nitrogen fertilizer during wintertime has increased the growth, although it has given clearly weaker results than applications carried out during the growing season (Paavilainen 1969). There is no corresponding information available about peatlands with a thin peat layer, and the effect of the time of application on peat and mineral soils has not been compared. The aim of this study is to shed some more light on questions that have been dealt with earlier and which form the basis of the nitrogen fertilization of peatland forests. In particular, an attempt is made to investigate how peat thickness and time of fertilizer application affect the uptake of fertilizer nitrogen by Scots pine (Pinus silvestris L.). Urea labelled with 15N isotope has been used in the study. No studies have earlier been carried out in Finland using this isotope technique in connection with forest fertilization, the usefulness of which has been shown by authors in other countries (e.g. Nömmik 1966, Björkman, Lundeberg & Nömmik 1967, Overrein 1967, 1968, 1969, 1970, 1971 a, b, 1972, Nömmik & Popovic 1971, Ivanko 1972). The following points are investigated in the study: - the uptake of fertilizer nitrogen, applied as urea, by pines growing on peatlands with a thick peat or a shallow peat layer and on a mineral soil site for comparison, the dependence of nitrogen uptake on the time of fertilizer application and the growing season, 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea ... 7 the retention of fertilizer nitrogen by different parts of pine and the ground vegetation, the leaching and volatilization of nitrogen given as urea in peat soils. The author has already published some preliminary results of this study at the 4th International Peat Congress (Paavilainen 1972 b). 2. MATERIAL AND METHODS The field and laboratory experiments were carried out at the Forest Research Institute's research station at Parkano. The research plan involved three separate parts. 1. The purpose of the broadest experiment, i.e. that set up on forest covered soils, was to determine the uptake of 13N urea fertilizer by pine and ground vegetation, and its dependence on the thickness of the peat layer and the time of fertilizer application. 2. In order to supplement the above experiment, an experiment was set up on a Sphagnum fuscum open swamp designed to investigate how the nitrogen from the urea fertilizer is retained in the peat when application is carried out on top of a snow cover or on the bare ground. Above all, it was thus used to determine the significance of the time of fertilizer application. 3. The third experiment was carried out in the laboratory and was designed to show whether nitrogen from the urea fertilizer is volatilized from the surface of the peat and how the fertilizer nitrogen leaches through the peat when varying amounts of water are applied onto the peat surface. Thus, attempts were made even in the laboratory experiment to determine the significance of the time of fertilizer application and thus to further supplement the field experiments. The results were treated in the Peatland Forestry Department of the Forest Research Institute. Variance analysis was used for determining the significance of the various factors making up the experimental results. In order to do this, arc sin transformation was done from the percentage values. The 15N analyses, which were the basic measurements obtained in the study, were carried out at Valio's Biochemical Research Institute. Other nutrient- and all other soil analyses were carried out by Viljavuuspalvelu Oy. Owing to the great expense of the analyses, it became necessary to reduce the number of samples from that which had been planned when the experi ments were originally set up. 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using "N labelled urea ... 9 2 15579—73 21. Experiment on forest covered soils The experiment which was designed to find out about the uptake of nitrogen from 15N urea fertilizer by pine and ground vegetation was set up at Alkkianvuori (N 62°10', E 22°45') situated in the Parkano experimental area of the Forest Research Institute. The area is located about 190 m above sea level. Adjacent thick peated peatland (peat thickness 100—160 cm) and shallow peated peatland (peat thickness 10—30 cm) sites, and for com parison a Vaccinium Type site (= VT, for the Finnish forest site classifica tion see Caj and e r 1949), were chosen for the study (Fig. 1). Fig. 1. Location of the sample trees on the experimental area Kuva 1. Koepuiden sijainti tutkimusalueella. Eero Paavilainen 10 79.2 The peatland sites closely resembled the sedge pine swamp and shallow sedge pine swamp types (cf. Huikari 1952), although the surface peat was drier than is normal for these types and partly covered by Carex globu laris. The coverage of some of the most common plant species occuring on these sites are presented below. The values represent average values for the species growing on ten sample plots of 1 m 2 each. Table 1. Results from analyses made on the soils in the experimental areas. Taulukko 1. Maa-analyysien tuloksia tutkituilla kasvupaikoilla. Plant species Sedge pine swamp Shallow sedge pine swamp Coverage, % VT site Vactinium myrtillius . . 10 25 40 Vaccinium vitis-idaea . . 3 5 30 Vaccinium uliginosum . 15 15 — Calluna vulgaris 2 2 20 Ledum palustre 45 40 — Betula nana 6 4 — Pleurozium Schreberi . . 8 40 80 Sphagnum sp 90 60 — Specific Organic Volume gravity, matter, % Depth, cm weight, g/1 g/cm 3 Orgaani- pH N tot. Ptot. К tot. C'atot- Syvyys, cm Tilavuus- Ominais- nen aines, mg/100 g mg/g mg/g mg/g paino, g/1 vaino, % g/cm s edge pine swamp Suursaramme 0—5 123 1.20 78.7 4.8 1.08 0.55 0.74 0.90 6—10 152 1.30 81.7 4.6 1.28 0.70 0.63 0.87 10—15 230 1.23 82.8 4.5 1.58 0.88 0.48 0.84 15—20 236 1.57 87.2 4.5 1.75 0.93 0.41 0.82 Shallow sedge pine swamp Ohutturpeinen suursaramme 0—5 189 1.32 76.9 4.7 • 1.45 0.70 0.70 0.84 5—10 140 : 1.39 77.1 5.0 1.17 0.63 0.66 0.91 10—15 334 1.42 63.8 4.8 1.64 0.97 0.49 0.64 15—20 877 2.57 10.8 4.8 0.21 0.12 0.21 0.06 'phagnum fuscum open swamp Rahkaneva 0—5 173 1.35 79.0 4.0 0.98 0.50 0.64 •• 5—10 164 1.40 69.0 3.9 0.94 0.70 0.69 10—15 190 1.45 80.5 3.9 1.11 0.70 0.48 ; ; 15—20 185 1.39 76.0 3.8 0.88 0.4O 0.27 VT site J Puolukkatyypin kangas Humus 304 1.44 56.3 4.3 0.90 0.86 0.52 0.4O Mineral soil Kivennäismaa P HCI sol. K HC1 sol. CaHCl sol mg/g mg/g mg/g 0—5 1 121 2.52 3.8 4.7 0.09 0.13 0.16 0.03 5—10 1 158 2.55 З.з 5.1 0.06 0.59 0.21 0.02 10—15 1 135 2.48 З.з 5.3 0.07 1.25 0.23 0.O2 15—20 1 130 2.39 3.4 5.4 0.07 1.26 0.23 0.O2 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea ... 11 It seems likely that the forementioned peatland sites have earlier been of the YT type, and gradually a part of the area has become paludified and turned into a shallow sedge pine swamp, and as a result of more advanced paludification another part has turned into a deep sedge pine swamp. The analyses carried out on samples taken from near some of the sample trees, which are discussed later in part a) on page 14, give some idea about the physical properties of the soil, pH values, and nutrient status of the study areas. These analyses showed, that there was a high mineral soil content at a depth of 15—20 cm in the samples taken from the shallow sedge pine swamp and also rather much organic matter (10.8 %) when compared with the mineral soil samples taken from the VT site in which the level of organic matter was only 3.3—3.8 % (Table 1). The volume weight of the peat was slightly greater and the nitrogen and phosphorous level was slightly higher at the surface of the peat (0—5 cm) in the shallow sedge pine swamp than in the deep sedge pine swamp. On the basis of measurements carried out in different parts of the VT site, the thickness of the humus layer was on average 3.1 cm. The soil texture composition of both the VT site and the shallow sedge pine swamp is presented in Table 2. Table 2. The texture of mineral soil in the experimental areas. Taulukko 2. Kivennäismaan raekoostumus tutkituilla kasvupaikoilla. Eighteen sample trees were selected at random from each of the three sites for detailed study (Fig. 1). The average dimensions of them were as follows: The mean age of the trees was 70—90 years. Depth, cm Syvyys, cm Soil texture, % Raekoostumus, % Gravel Sora (20—6 (6—2 mm) mm) Sand Hiekka (2—0.6 (0.6 —0.2 mm) mm) Fine sand Hieta (0.2— (0.06 — 0.06 0.02 mm) mm) Silt Hiesu (0.02 — (0.006— 0.006 0.002 mm) mm) Clay Savi (0.002 mm) 15—20 5 1 Shallow sedge pine swamp Ohutturpeinen suursararäme 9 21 45 10 5 2 2 0—5 5—10 . .. . ! 10—15 15—20 4 3 10 2 13 4 11 5 VT site Puolukkatyypin kangas 9 26 1 39 10 9 24 ! 34 10 10 23 34 8 9 31 1 25 9 i 5 2 6 2 4 1 5 2 2 3 ! Diam. at breast height, cm Height, ш Length of the living crown as % of the total height Sedge pine swamp 11.9 8.0 48 Shallow sedge pine swamp 11.7 9.8 57 VT site 12. о 10.4 55 Eero Paavilainen 12 79.2 The root studies, discussed later in part b) (p. 14), showed that in the case of the sedge pine swamp, the roots of the sample trees were found in most cases near the surface, but in the VT site they were found much deeper. The average depth of the root systems of pine in the sedge pine swamp was 3.8 cm, 5.6 cm in the shallow sedge pine swamp, and 7.0 in the VT site (Table 3). The depth distribution of the root systems of the ground vegetation did not show a corresponding trend, for they were closest to the surface in the VT site and deepest in the shallow sedge pine swamp. The super ficiality of pine root systems in peatlands as compared to mineral soils, has been demonstrated also in several earlier studies (e.g. Kalela 1949, Heikurainen 1955, Paavilainen 1966). It can also be seen in Table 3 that the total length of pine roots was approximately the same in all the sites studied. The total length of ground vegetation roots was greater in the swamp sites than in the VT site. Each sample tree was isolated from its surroundings by means of poly thene sheeting which extended from the ground surface down to a depth of half a meter (Fig. 2) at a distance of 2 m from the base of the trunk. A total of 20 gof urea fertilizer containing 15N isotope ( 15N excess 0.9 %) was spread in 0.5 m wide strips at right angles to each other, with the sample tree at the point of intersection, within the area enclosed by the polythene Fig. 2. Sample tree isolated from its surroundings by polythene sheeting. Kuva 2. Ympäristöstään muovilla eristetty koepuu. 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea 13 Table 3. Amount of roots in the various sites studied. Taulukko 3. Juurten määrä eri kasvupaikoilla. Sedge pine swamp Suursararäme Shallow sedge pine swamp Ohutturpeinen suursararäme VT-site VT-kangas Depth, cm Syvyys, cm Pine roots Männyn juuria m/m* Ground vegetation roots Pintakas- kasvilli- suuden juuria m/m1 Total amount of roots Juuria yhteensä m/m* Pine roots Männyn juuria m/m* Ground vegetation roots Pintakas- villi- suuden juuria m/m" Total amount of roots Juuria yhteensä m/m2 Depth, cm Syvyys, cm Pine roots Männyn juuria m/m* Ground vegetation roots Pintakas- villi- suuden juuria m/m" Total amount of roots Juuria yhteensä m/m* 0—5 5—10 10—15 15—20 271.0 83.6 1.6 1.2 720.7 331.2 215.7 213.4 991.7 414.8 217.3 214.6 179.7 99.5 39.7 6.7 409.6 459.6 318.1 250.4 589.3 559.1 357.8 257.1 Humus (0— 3.1 cm) Mineral soil Kivennäismaa 0—5 5—10 10—15 15—20 160.8 73.1 43.8 42.4 20.O 534.8 251.5 152.8 135.7 78.2 695.6 324.6 196.6 178.1 98.2 Total — Yhteensä 357.4 1 481.0 1 838.4 325.6 Average depth of root system Juuriston keskisyvyys') | 3.8 j 7.2 [ .. ] 5.6 *) Average depth of roots weighted by the length of roots (cf. Kalela 1949) Juurten pituudella punnittu keskisyvyys (vrt. esim. Kalela 1949). 1 437.7 8.9 1 703. 3 340.1 7.0 1 153.0 7.1 1 493.1 14 Eero Paavilainen 79.2 sheeting. The total fertilized area around each sample tree thus measured 3.7 5 m 2. The quantity of fertilizer used was equivalent to 53.3 kg N/ha. Fertilizer applications were carried out on 18. 12. 1970, 1. 3. 1971, 27. 4. 1971, 19. 5. 1971 and 16. 7. 1971. The sample trees to be fertilized at different times were selected randomly, there being three of them on each site at each time of fertilizer application. In addition, three sample trees were left unfertilized on each site to act as controls. The uptake of fertilizer nitrogen by the sample trees was studied on the basis of needle analysis. The needle samples were taken from the third branch whorl counted from the top of the tree. Samples were taken from the unfertilized control trees once a month between Jan.—Oct. 1971, and from the fertilized trees also once a month commencing from the time of fertilizer application. The samples taken between Jan.—June comprised needles produced in 1970, and those taken between July—Oct. ones produced in 1971. Initially, the 15N level of 12 sample trees fertilized between Jan.— April and 4 control trees was analysed. After the analyses showed that these samples contained no nitrogen originating from the fertilizer, further analyses were limited to those samples taken between May—Oct. 1971. The total nitrogen content of these samples and the proportion of nitrogen originating from the fertilizer was then determined. In addition to the earlier mentioned study objects, sample trees fertilized in May and unfertilized control sample trees were selected from each site (sample trees No. 2, 4, 6, 7, 19, 28, 30, 35, 37, 44, 45, 54) and used for further study. The following factors were investigated: a) The physical properties and the nutrient level of the soil. Two samples were taken from next each sample tree between 10.—20. 10. 1971 (one from each side of the tree in the unfertilized areas situated at a distance of about 1 m from the tree) using the soil sampler developed by Juusela, Kaunisto and Mustonen (1969, p. 9—11). The samples which had a diameter of 19 cm were taken down to a depth of 30 cm. Those taken from peatlands were divided from the surface downwards into 5 cm long sections, and those from the mineral soil site also into 5 cm long sections after the humus layer had been separated away. The results of the analyses carried out on these samples are presented in Tables 1 and 2. b) The structure of the root systems of the tree stands and the ground vegetation. The samples used in the study were taken from the fertilized areas near to the sample trees using the same technique and at the same time as those in a). The root systems were studied by the quantitative method proposed by K a lela (1949), Heikurainen (1955) and Paavilainen (1966). The length of the roots of the pines and the ground vegetation were studied in the same layers as those in which the analyses concerning the physical properties of the soil and the nutrient level were made. c) The total nitrogen content and the proportion of 15N fertilizer nitrogen in the total nitrogen of the trunk, bark, and different aged needles in different parts of the tree. The sample trees were felled for this purpose on 19. —20. 10. 1971 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea . 15 and their crowns divided into three parts. Needles produced in 1969, 1970 and 1971 were taken from each third for analysis. Although stem wood and bark samples were taken from five different points along the trunks, only the nitro gen content of samples taken from halfway along the trunk were actually measured. d) The total nitrogen content and the proportion of 15N fertilizer nitrogen in the total nitrogen of the dwarf shrubs and other plants forming the field layer, and mosses. Samples representative of the fertilized area next to each sample tree were collected for this purpose on 19. —20. 10. 1971. About 20 % of the mosses and 80 % of the dwarf shrubs and other field layer plants growing on the fertilized areas were collected for analysis. e) The 15N content in the peat (0—20 cm) and roots of the trees and ground vegetation growing on sedge pine swamps. The analyses concerning the root systems were carried out on the samples described in b). Two separate samples were taken from the fertilized area next to each sample tree in the same way as in b) for studies on the peat. f) Estimation of the biomass of the trees and ground vegetation growing on sedge pine swamp. The stump and rootstock of sample tree No. 54 was dug out of the ground for this investigation. Samples were then taken from the stump, trunk and crown and their dry weight measured by weighing. The values obtained were multiplied by the respective ratios between the measured fresh weights in order to obtain values for the various parts of the tree in question. The dry weight (g/m 2 ) of the ground vegetation and the fine roots was determined using samples obtained in the forementioned manner. Thus a rough estimate was obtained which could be used to determine the ratio between the biomass of the trees and the ground vegetation. Figure 3 shows the meteorological conditions prevailing during the study period, and includes the average daily temperature and amount of precipita tion for the period Sept. 1970—Oct. 1971. The observations were made at the Alkkia meteorological station of the Parkano research station, situated about 6 km from the experimental area. Some idea of the variations in the thickness of the snow cover can be obtained from the measurements made on a Spagnum fuscum open swamp situated 4 km away. The results are presented later on in this paper (p. 33). The snow thickness on the experi mental area was also measured and meteorological observations were made whenever fertilizer was applied or needle samples taken. Fig. 3. Air temperature and amount of precipitation recorded at Alkkia meteorological station. Kuva 3. Ilman lämpötila ja sateen määrä Alkkian säähavaintoasemalla. Eero Paavilainen 16 79.2 22. Experiment on a Sphagnum fuscum open swamp A comparative field experiment concerning the movement of 15N urea fertilizer was set up on a drained Sphagnum fuscum open swamp. The pH value of the peat was clearly lower and the nutrient level also lower in this type of peatland than in the sedge pine swamp (Table 1). Sixty four experimental points were marked out near the ditches on the Sphagnum fuscum open swamp (Fig. 4). Circular areas with a diameter of 19 cm (same size as the samples used in the laboratory experiment) situated next to the points, received surface fertilizer applications of 1 g 15N labelled urea. The fertilizer dose was given to three randomly selected points at each application time. Altogether, fertilizer applications were carried out 18 times at weekly intervals between 2. 1.—29. 4. 1971. In addition, ten unfertilized control points were left on the experimental area. Fig. 4. Fertilized sample points (open circles) and the points where snow depth and water equiva lent values were measured (circles containing a cross). Kuva 4. Lannoitetut koepisteet (avoimet ympyrät) sekä lumen syvyyden ja vesiarvon mittauskohdat (ympyrät, joiden sisällä risti). 17 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea 3 1557 9—7 3 The thickness and density of the snow was measured at three observation points on the experimental area during the experiment (Fig. 4). The thickness of the snow layer and the water equivalent values of the snow can he seen in Fig. 9, p. 33. Soil samples were taken from all the experimental points during 11. 6. — 14. 6. 1971. The cross-sectional area of the soil sampler was 4 cm x 5 cm. Sampling was done within the fertilized circle down to a depth of 20 cm from the peat surface and the samples were then divided, after removal of the litter and living moss layer, into 5 cm long sections measured from the peat surface downwards. As analysis of all the samples was economically impossible, two unfer tilized control samples and ten samples from the points fertilized at the following times were analysed: 2. 1., 5. 1., 5. 2., 5. 3., 26. 3., 2. 4., 8. 4., 16. 4., 23. 4. and 29. 4. 1971. Most of these samples had been fertilized at times when changes in the snow cover were greatest. 23. Laboratory experiment The possible volatilization and downward movement in peat of the nitrogen given as urea was also studied in the laboratory. The experiment was carried out at the Forest Research Institute's Alkkia field station during the period 7. 1.—6. 2. 1971. Samples for this purpose were taken with the forementioned soil sampler developed by Juusela, Kaun i s t o and Mustonen (1969, p. 9—11), which meant that the samples could be placed in plastic tubes (diameter of 190 mm) without disturbing the structure of the soil. The samples were 50 cm long. A container was tightly attached under every plastic tube so that all the water passing out of the samples could be collected. The samples used in this experiment were taken from the same sedge pine swamp as that used as one of the sites in the forest covered soils experi ment. Altogether, there were 54 samples which were divided up on the basis of fertilization and irrigation intensity into the following treatments: Irrigation, mm/day Fertilization 0 0.5 1 2 4 No. of samples 15N labelled urea, 1 g 9 9 9 9 9 No fertilization 9 — — — — 18 Eero Paavilainen 79.2 Of the samples that received each treatment combination, 3 were taken for further treatment after 10 days, 3 after 20 days, and 3 after 30 days from the beginning of the experiment. Fertilization, irrigation intensity, and the time at which the samples were removed for further study, were all selected randomly. In order to prevent edge effects, an untreated 1 cm wide strip was left around the edge of the container whenever fertilization or irrigation was carried out. Before further studies were performed on the samples, they were divided from the surface downwards into 5 cm long sections. When the sample parts were analysed, the 15N content down to a depth of 50 cm was first determined in two of the samples which had received the strongest irri gation intensity (4 mm daily irrigation for 30 days). Analysis of the re maining samples was restricted to the first 15 cm, after it became clear that only a very small amount of the fertilizer nitrogen in the above samples had moved deeper than 15 cm. The air temperature and relative humidity were measured during the experiment with a thermohygrograph placed at the same level as the upper surface of the experimental containers. The air temperature and relative humidity recorded during the experiment are presented in Fig. 5. 19 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea ... Fig. 5. Air temperature and relative humidity during the laboratory experiment. Kuva 5. Ilman lämpötila ja suhteellinen kosteus laboratoriokokeessa. 3. RESULTS 31. Uptake of fertilizer nitrogen by pine 011 the basis of needle analysis As was earlier mentioned on p. 14, the nitrogen content of needle samples taken at different times were initially determined by spot checkning. As no nitrogen originating from the fertilizer was found in needle samples taken between Jan.—April, the nitrogen content of the needles was de terminated only in the samples taken between May—Oct., apart from the ones used for spot checks. The effect of site, time of fertilizer application, and time of needle col lection on the nitrogen content of the needles was found to be statistically significant (Table 4). As the material collection in October consisted of only one time of fertilizer application, a corresponding analysis was not carried out. The total nitrogen content of the needles is presented in Fig. 6, and the proportion of the total nitrogen originating from the urea on different sites in Fig. 7. Table 4. Results of the significance tests for the nitrogen content of the pine needles. Samples taken in May-September. Taulukko 4. Merkitsevyystestien tulokset eri tekijöiden vaikutuksesta männyn neulasten typpipitoisuuteen. Touko-syyskuussa otetut näytteet. Source of variation Vaihtelun aiheuttaja Total nitrogen content of needles Neulasten kokonaistyppi- pitoisuus Proportion of N" fertilizer in total nitrogen Lannoitetypen osuus kokonaisty pestä F F Site — Kasvupaikka 7.58*** 6.66** Application time — Lannoitteen levity 3.47** 3.05* Ir" S VUjVUIVVVIV w 1 Time of sampling — Neulasten ottoaika 44.47*** 40.16*** Application time x site — Levitysajankohta x kasvupaikka : - 5.02*** ') * = significant at 95 % confidence level merkitsevä 95 %:n luotettavuudella ** = significant at 99 % confidence level merkitsevä 99 %:n luotettavuudella *** = significant at 99.9 % confidence level merkitsevä 99.9 %:n luotettavuudella 21 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea ... 79.2 Fig. 6. Total nitrogen content of the pine needles. Kuva 6. Männyn neulasten kokonaistyppipitoisuus. Eero Paavilainen 79.2 22 Fig. 7. Proportion of fertilizer nitrogen in the total nitrogen of the pine needles. Kuva 7. Lannoitetypen osuus männyn neulasten kokonaistypestä. 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea ... 23 311. Effect of the site It can be seen from Fig. 6 that the total nitrogen content of the sample tree needles was greatest on the sedge pine swamp (on average 1.13 %), next highest on the shallow peated sedge pine swamp (1.12 %), and lowest on the VT site (1.04 %). However, the nitrogen content of the needles from the sedge pine swamp was also quite low. Paaria h ti, Reini kainen & Veijalainen (1971) for instance, have come to the conclusion that nitrogen should be included in the fertilization of peat lands, if the nitrogen content of the needles is lower than 1.20 %. The proportion of fertilizer nitrogen in the total nitrogen was highest 011 the mineral soil site and showed a decreasing trend as the thickness of the peat increased (Fig. 7). The effect of the site on the proportion of fertilizer nitrogen thus had an opposite effect to that which it had on the total nitrogen content of the needles. The results prove, that the sample trees growing on the peatlands have clearly taken up less fertilizer nitrogen given as urea than those on the mineral soil site and on the thick peated peatland less than on the shallow peated one. The amount of fertilizer nitrogen bound by the needles on the VT site was approx. 2.3 times higher and on the shallow peated sedge pine swamp 1.6 times higher per unit dry weight than on the thick peated sedge pine swamp. 312. Effect of the time of fertilizer application A total of five different times of fertilization application were used in the study: 18. 12. 1970, 1. 3. 1971, 17. 4. 1971, 19. 5. 1971 and 16. 7. 1971. At the time when fertilizer was applied in Dec. 1970, there was approx. 5 cm of snow on the ground. However, the snow cover was removed and the fertilizer applied to the bare ground. The air temperature was —3 °C. When fertilizer application was carried out in March 1971, there was 30—35 cm of snow on the thick peated sedge pine swamp and 25—30 cm on the other sites used in the study. The air temperature was —l5 °C. The snow thickness at the time of fertilizer application in April was approx. 10 cm, and the air temperature was -f-5°C. The July fertilization was carried out after quite a long period of low rainfall (cf. Fig. 3), but rain was falling during the actual application. The air temperature was +l5 °C. The time of fertilization application had a significant effect on the total nitrogen content of the needles of the sample trees (cf. Table 4). The nitrogen content of the needles of the sample trees which received fertilizer in July was lower on average than the others. The most likely reason for this is that 24 Eero Paavilainen 79.2 needle samples were taken from these sample trees only in August and September, at which time the nitrogen level in needles is usually low. The time of application clearly affected the extent to which the sample trees took up nitrogen given as urea (Fig. 7). The proportion of fertilizer nitrogen in the total nitrogen of the needles taken from the sample trees which received the urea fertilizer on snowless ground before the start of tree growth was approximately twice the level in the sample trees which received the fertilizer on top of the snow cover. The trees have not been able to take up much nitrogen from the fertilizer given in July during the same year as the fertilization was carried out. The effect of the time of application was significantly dependent upon the site (cf. Table 4). It can be seen from Fig. 7, that the differences between the various times of application were greater on the mineral soil site than on the peatlands. In addition, the results show that the effect of fertilization in May on the shallow peated sedge pine swamp remained relatively weaker than on the other sites. HoAvever, this result may have been caused by other factors, apart from the site properties, because the other application carried out during a snowless period (in Dec. 1970) has also increased the proportion of 15N nitrogen in the total nitrogen of the needles on the shallow peated sedge pine swamp to a similar extent as on the other sites. As regards applications made on the bare ground, quite as good re sults have been obtained when application has been done on thawed ground in the spring before tree growth starts, as when it has been done on strongly frozen ground in December. The effect of the time of application was in this case also less on the peatlands than on the mineral soil site. 313. Nitrogen content of the needles at different times during the growing season After comparing the nitrogen content of the needles at different times (Fig. 6), it becomes clear that the nitrogen content of the needles produced in 1970 was, in the case of the whole material, on average 1.04 % in May and fell to 0.92 % towards the middle of June. The nitrogen content of the new needles produced in 1971 was on average 1.34 % in the middle of July and then clearly decreased until the middle of August to 1.0 5%. In September, the total nitrogen content of the needles increased to 1.16 % and further increased in October to 1.20 %. This last result, however, is questionable because the material for October was small. According to several earlier studies, noticeable variations in the nutrient content of the needles do occur throughout the growing season (e.g. White 1954, Tamm 1955, 1968, Hoffmann 1967). For example, the results which T a 111 m 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea . 25 4 15579—73 (1955) obtained show that the nutrient content in the needles was at its greatest late in the autumn and winter, and at its lowest in the beginning of the summer. The trees have taken up only a small amount of fertilizer nitrogen by the middle of June. The proportion of fertilizer nitrogen in the total nitro gen of the needle samples taken in May was on average O.oi %, and of those taken in June 0.0 4 %. The proportion of fertilizer nitrogen in the samples taken in July, which were new needles produced in 1971, was noticeably greater on average 0.5 6 % of the total nitrogen. The pro portion of fertilizer nitrogen then changed and showed the same trend as the total nitrogen level of the needles, i.e. the level decreased in August and increased again in September. The proportion of fertilizer nitrogen in the total nitrogen of the needles is smaller in this study than that which for instance N ö mmi k (1966) and Björkman, Lundeberg & N öm m i k (1967) have presented. The proportion of fertilizer nitrogen in the total nitrogen of the needles, according to N ö m m i k's material (1966), was on average 2.23 % by the end of the first growing season. The corresponding proportion found in this study was less than 1.00 %. The most likely reason for this is the small amount of fertilizer (53.3 kg N/ha) used in this study, and the fact that large trees were studied while Nömmik (1966) used seedlings about 10 years old in his experiments. The results show that the sample trees have taken up fertilizer nitrogen, given as urea, so slowly that the nitrogen content of the needles can effectively be affected in the year of fertilization if fertilization is carried out before the start of the trees' growing season. The low 15N content of the samples taken in May and June, as well as the results of analyses carried out on samples taken between Jan.—Apr. (cf. p. 14), show that the sample trees have been able to taken up very little, if any at all, of the fertilizer nitrogen before the start of the growing season. 32. Retention of fertilizer nitrogen by different parts of the tree and ground vegetation 321. Crown of the tree The total nitrogen content and the proportion of fertilizer nitrogen in the total nitrogen of different aged needles from pines growing on various sites was studied using sample trees (cf. p. 15) felled at the end of October. The analyses concerning the total nitrogen were carried out on samples taken from the upper third of the crown, the middle part of the crown,, 26 Eero Paavilainen 79.2 Table 5. Nitrogen content of pine needles in different parts of the crown. Taulukko 5. Männyn neulasten typpipitoisuus latvuksen eri osissa. and the lower third of the crown. The proportion of fertilizer nitrogen was studied on needle samples taken only from the upper third of the crown. The results of the analyses are presented in Table 5, and the statistical significance of the effect of different factors, can be found in the following text table. The effect of the site on the total nitrogen content of the needles and the proportion of fertilizer nitrogen in the total nitrogen was not statisti cally significant in this part of the study material. The needle age did not have a significant effect either. The variance analysis did show, however, that the position of the needles in the crown had a significant effect on the total nitrogen content of the needles. Needles produced in the year N eulasvuosikerta Site Kasvupaikka 1969 1970 19' 71 A Б A В A ]! Upper part of the crown Latvuksen ylin osa Sedge pine swamp — Suursaramme 1.15 0.21 1.13 0.1 G 1.18 0.3» Shallow sedge pine swamp — Ohutturpeinen suur- sararäme 1.15 0.20 1.23 0.31 1.21 0.31 VT site — VT kangas 1.14 0.50 1.1 5 0.48 1.21 0.7 2 Middle part of the crown Latvuksen keskiosa Sedge pine swamp — Suursararäme 1.18 1.21 1.23 Shallow sedge pine swamp — Ohutturpeinen suur- sararäme 1.34 1.41 1.38 VT site — VT kangas 1.29 1.37 1.34 Lower part of the i :rown Latvuksen al iti osa Sedge pine swamp — Suursararäme 1.26 1.32 1.33 Shallow sedge pine swamp — Ohutturpeinen suur- sararäme 1.31 1.34 1.38 VT site — VT kangas 1.27 1.28 1.28 A = Total nitrogen content of needles, % — Neulasten kokonaistyppipitoisuus, % В = Proportion of N fertilizer in total nitrogen, % — Lannoitetypen osuus kokonaistypestä, % Total nitrogen Proportion of Source of variation content of the fertilizer N in needles the total nitrogen F F Part of the crown . . . . 8.89*** — Site 3.00 1.20 Age of the needles 1.31 0. 43 79.2 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea ... 27 The total nitrogen content of the needles in the top of the crown was smaller on average than in the middle part and in the lower third (Table 5). In the study carried out by Björkman, Lundeberg & Nömmik (1967), the nitrogen content of the needles in the top of the crown was 1.09 %, in the middle part 1.14 %, and in the lowest third 1.16 %. When estimating the total amount of fertilizer nitrogen retained by the needles, the results of the analyses made on needle samples taken from the top of the crown have been considered to represent the proportion of fertilizer nitrogen. In the case of the branches, the values obtained from the analyses carried out on pine stemwood and bark samples have been con sidered to represent the proportion of fertilizer nitrogen. 322. Trunk and root system of the tree It can be seen from the analysis results presented in Table 6, that the nitrogen content of the stemwood of the sample trees was very low (0.0 4 0.06 %) on all the sites studied. The proportion of fertilizer nitrogen in the total nitrogen of the stemwood was also small, the calculated averages for the different sites varying between 0.21—0.3 3 %. The nitrogen content of the bark of the sample trees was on average 0.3 3 —0.4 4%, which is noticeably greater than that in the stemwood. The proportion of fertilizer nitrogen in the bark samples was also greater than in the stemwood. These estimations were carried out on samples taken Table 6. Nitrogen content of stem and root system of pine. Taulukko 6. Männyn rungon ja juuriston typpipitoisuus. Proportion of N fertilizer in total Site Total nitrogen, % nitrogen, % Kasvupaikka Kokonaistyppi, % Lannoitetypen osuus kokonaistypestä, % Stem wood - — Runkopuu Sedge pine swamp — Suursaramme 0.05 0.25 Shallow sedge pine swamp —• Ohutturpeinen suursara- 0.04 räme 0.21 VT site — VT kangas 0.06 0.33 Bark — Kuori Sedge pine swamp — Suursararäme 0.33 0.43 Shallow sedge pine swamp — Ohutturpeinen suursara- räme 0.44 0.33 VT site •— VT kangas 0.42 0.4O Root system 1 •— Juuristo Sedge pine swamp — Suursararäme 0.69 0.64 Eero Paavilainen 28 79.2 from halfway along the trunk. A better idea would have been obtained about the nitrogen content of the whole of the trunk, which may vary at different heights (cf. M älkönen 1970), if samples taken from different heights had been studied. Unfortunately this was not possible. When Mälkönen (1972) calculated the amount of nutrients re moved from stands by harvesting, he found that the nitrogen content of the stemwood was 0.0 6 7 % N, and that of the bark was 0.31 %. There were comparatively clear differences in the nitrogen content of samples taken from different sites, but the effect of the site was not sta tistically significant (for the total nitrogen in the stemwood F = 0.56, and in the bark F = 4.31; for the proportion of fertilizer nitrogen in the stemwood F = 1.49, in the bark F = 0.33). The nitrogen content of the root systems was determined only for the sample trees growing on the sedge pine swamp. The total nitrogen content of the root systems was on average 0.69 %, and the proportion of fertilizer nitrogen in the total nitrogen was 0.6 4 %. 323. Ground vegetation The dwarf shrubs and mosses making up the ground vegetation were examined separately on all the three sites. However, all the roots of the ground vegetation were handled together, and only those from the thick peated sedge pine swamp were subjected to analysis. The results presented in Table 7 show that the nitrogen content of the dwarf shrubs varied between 1.07 —1.30 %. The proportion of fertilizer nitrogen in the total nitrogen was 2.5 3—3.91 %, which was noticeably greater than that in the pine needles (cf. Fig. 7). The site did not signifi cantly affect the total nitrogen content of the dwarf shrubs (F = 1.40) or the proportion of fertilizer nitrogen in the total nitrogen (F = 0..30). The total nitrogen content of the mosses was slightly lower than that of the dwarf shrubs, 0.93 —1.04 %. The mosses retained greater amounts of fertilizer nitrogen than the dwarf shrubs, as the proportion of fertilizer nitrogen in the total nitrogen of the mosses was 8.47 —11.3 4 %. The site did not significantly effect the total nitrogen content of the mosses (F = 4.2 8), nor the proportion of fertilizer nitrogen in the total nitrogen (F = 0.37). The total nitrogen content (0.70 %) and the proportion of fertilizer nitrogen in the total nitrogen (0.47 %) of the root systems of the ground vegetation are approximately the same as those of the pine root systems. 29 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea ... 79.2 Table 7. Nitrogen content of ground vegetation. Taulukko 7. Pintakasvillisuuden typpipitoisuus. ■324. Total amount of fertilizer nitrogen retained by the tree and ground vegetation The dry weight of sample tree No. 54 and the ground vegetation sur rounding it were determined (cf. p. 15) in order to study how much nitrogen, given as fertilizer, has been retained by the trees and the ground vegetation. The dry weights for the ground vegetation were calculated on the basis of the area where fertilization was supposed to have affected the nitrogen level of the organic material. Estimation of the effect of fertilization in the case of the mosses was restricted to the 0.5 m wide fertilized strip. The area affected by fertilization in the case of the dwarf shrubs was larger, because it was clear from the root studies that the roots of the dwarf shrubs grew into the fertilized area from quite far outside. As an exact analysis could not be done, it was assumed that the effect area for the dwarf shrubs was 8 m 2. In the case of the root system of the sample tree, the whole area limited by the polythene sheeting was regarded as the affected area. The calculated dry weights can be seen in the following table. Proportion of N fertilizer in total Site Total nitrogen, % nitrogen, % Kasvupaikka Kokonaiatyppi, % Lannoitetypen OSUUS kokonaistypestä, % Dwarf shrubs — Varvut Sedge pine swamp — Suursaramme 1.30 2.53 Shallow sedge pine swamp — Ohutturpeinen suursara- räme 1.18 3.06 VT site — VI ' kangas 1.07 3.91 Moss vegetatioi — Sammalet Sedge pine swamp — Suursaramme 0.93 8.47 Shallow sedge pine swamp — Ohutturpeinen suursara- räme 1.04 11.02 VT site — VT kangas . 1.02 11.34 Root system of ground vegetation Pintakasvillisuuden juuristot Sedge pine swamp — Suursaramme 0.70 0.47 Dry weight, kg Pine 1.2 2.9 13.3 Stump and thick roots 9. 7 Fine roots 1.7 Eero Paavilainen 30 79.2 The total amount of fertilizer nitrogen retained by the sample tree and ground vegetation was calculated using these dry weight values and the results presented earlier concerning the total nitrogen level and the pro portion of fertilizer nitrogen in the total nitrogen. The proportion of bark was estimated to be 15 % of the dry weight of the stem, and the stump and thick roots. Furthermore, it was possible to calculate the organic matter content of the peat and using these results to estimate the amount of fertilizer nitrogen in the ground surrounding the sample tree. The amount of nitrogen in the ground down to a depth of 20 cm was naturally calculated per 0.5 m wide fertilized strip. The following results were obtained from the above calculations: The amount of fertilizer nitrogen retained by the vegetation and the ground in this study, was found to be slightly smaller than that which has been presented in earlier studies. Björkman, Lundeberg & N ö mm i k (1967) found that when ammonium sulphate was used, 79.3 % of the nitrogen had become bound during the first growing season, of which 20.8 % was in the vegetation and 58.5 % in the soil. According to Nö m mi k & Popo vi c (1971), 87.1 % of the urea nitrogen had been bound by the end of September in the year of fertilization, of which 13.2 % was in the vegetation. The general trend of the results obtained in this study is quite clear. Trees are obviously able to use only a very small part of the urea given as fertilizer during the first growing season when growing on sedge pine swamps. A noticeably greater part of the urea fertilizer is retained by the ground vegetation or remains in the ground, from where to a certain extent it can become available to the trees. Some of the nitrogen given as urea is probably not retained at all by the trees, ground vegetation or in the peat layer down to a depth of 20 cm. It has not been possible in this ex periment to find out whether any of the fertilizer nitrogen has been lost through leaching or volatilization. However, this question is discussed Ground vegetation Dwarf shrubs 3.0 Mosses 0.8 Roots 5.0 Percentage of the nitrogen given as fertilizer In the sample tree 2.3 In the ground vegetation 19.4 In the soil (0—20 cm) 44.0 Total 65.7 31 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea /9.2 later on in the study on the basis of the results of an experiment carried out in the laboratory and an experiment set up on a Sphagnum fuscum open swamp. 33. Leaching and volatilization of fertilizer nitrogen in peat soils The leaching and volatilization of urea from the peat surface were studied in the laboratory on samples taken from the experimental area on the sedge pine swamp (cf. p. 17). Urea containing 15N was spread on the surface of the peat samples and different irrigation intensities were then applied. The leaching of urea was also studied in the experiment set up on the Sphag num fuscum open swamp (p. 16). 331. Leaching The results of the analysis show that even when large amounts of water are given during irrigation, after 30 days the fertilizer nitrogen is still largely retained in the first 5 cm of the peat (Fig. 8). The depth distribution of nitrogen movement has been greater, the more water has been applied into the surface of the experimental containers. However, it has been found that when the strongest irrigation intensity is used, i.e. 4 mm/day, there is very little fertilizer nitrogen deeper than 15 cm. It can be seen below, that the differences between different peat depths and different irrigation intensities as regards the total nitrogen content and the proportion of fertilizer nitrogen were statistically significant. The interaction between the time elapsed since the start of the experiment and the depth of the sample, and also between the irrigation intensity and sample depth (in the case of the proportion of fertilizer nitrogen) were also significant. Proportion of N Source of variation Total nitrogen fertilizer in the total nitrogen F F Depth 9.9 6*** 319.65*** Irrigation intensity 3. 9 3** 7.86*** Time elapsed since start of the experiment . . . 0.72 0.9 1 Irrigation intensity X depth 0.72 2.58* Time X depth . . . . 2.0 5* 2.3 о* Eero Paavilainen 32 79.2 Fig. 8. Proportion of fertilizer nitrogen in the total nitrogen of the samples used in the laboratory experiment (average 10—30 days after the experiment commenced). Kuva 8. Lannmtetypen osuus kokonaistypestä laboratoriokokeen näytteissä (keskimäärin 10—30 vrk:n kuluttua kokeen aloittamisesta). The results of the experiment set up on a Sphagnum fuscum open swamp also show that the fertilizer nitrogen given as urea is strongly retained by the peat (Table 8). Several months after fertilizer application, most of the fertilizer nitrogen was still in the first 5 cm of the peat and the amount of nitrogen decreased from the surface downwards. However, some of the fertilizer nitrogen may have moved deeper than 20 cm in the peat, but judging by the results of the analyses obviously only very small quantities could be involved. 33 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea 79.2 5 15579—73 Table 8. Total nitrogen content of peat and the amount of nitrogen originating from the fertilizer at various depths after application at different times. Experiment on Sphagnum fuscum swamp. Analyses are made in 11.—14. 6. Taulukko 8. Turpeen kokonaistyppipitoisuus ja lannoitteesta peräisin olevan typen määrä eri syvyyksissä annettaessa lannoite eri ajankohtina. Rahkanevan koe. Analyysit on tehty 11.—14. 6. The time of application also had a clear effect on the retention of fer tilizer nitrogen (Fig. 9). When application was carried out on hare ground, noticeably more nitrogen remained in the peat than when it was applied onto a snow cover. The strongest nitrogen retention occurred when appli cation was carried out on frozen ground on 15. 1. 1971. It can be seen in the following text table that the total nitrogen content in the peat was not significantly dependent on the sample depth or the time of fertilizer application in the experiment set up on the Sphagnum fuscum Fig. 9. Snow thickness and water equivalent values, and proportion of fertilizer nitrogen in the total nitrogen of the experiment set up on a Sphagnum fuscum open swamp. Kuva 9. Lumen paksuus ja vesiarvo sekä lannoitetypen osuus kokonaistypestä rahkanevan kokeessa. Depth, сш Syvyys, cm 2.1. 15.1. 5.2. Time of application Lannoitteen levitysajankohta 5.3. 26.3. 2.4. 8.4. 16.4. 23.4. 29.4. Mean Keski- arvo Total nitrogen, % — Kokonaistyppi, % 0—5 1.00 0.89 0.94 0.89 0.90 1.00 0.87 0.94 0.96 0.94 0.93 5—10 0.90 0.92 0.93 0.85 0.83 0.82 0.74 0.98 0.93 0.69 0.86 10—15 0.87 0.93 1.02 0.85 0.69 0.87 0.82 0.89 0.81 0.94 0.87 15—20 0.82 0.89 0.84 1.00 0.82 0.93 0.78 1.07 0.59 1.18 0.89 Mean Keskiarvo 0.89 0.9O 0.93 0.89 0.81 0.90 0.80 0.97 0.82 0.93 0.88 Proportion of N fertilizer in total nitroger I, % - Lannoitetypen ( )suus k( ikonaish '/pesta, ° 'o 0-5 0.93 11.92 1.92 1.58 2.72 0.56 1.34 3.37 8.79 8.28 4.14 5—10 1.45 1.40 0.6O 0.43 0.68 1.94 0.86 0.76 2.07 2.69 1.29 10—15 0.48 1.45 0.37 0.85 0.34 0.52 0.58 0.63 0.95 1.22 0.74 15—20 0.48 0.75 0.57 0.31 0.52 0.34 0.35 0.29 0.59 0.4 5 0.47 Mean Keskiarvo 0.83 3.88 0.8« 1 0.79 1.06 0.84 0.78 1.26 3.10 3.16 1.66 Eero Paavilainen 34 79.2 open swamp. On the other hand, these factors had a significant effect on the proportion of fertilizer nitrogen. The interaction between the sample depth and the time of application was also significant. 332. Volatilization The laboratory experiment was also designed to find out whether nitro gen given as urea volatilizes from the surface of the peat. The temperature and humidity at the top of the experimental containers were measured during the experiment with a thermohygrograph. The results of these measurements are presented in Fig. 5 (p. 19). It can be seen from the results presented in Table 9, that when no irri gation at all was carried out, 75.3 % of the nitrogen given by fertilization remained in the sample. The amount of fertilizer nitrogen in the sample increased as the irrigation intensity was increased. In the case of the greatest irrigation intensity, i.e. 4 mm/day, more fertilizer nitrogen was found in the samples than had been given by fertilization. Nitrogen originating from urea fertilizer was also found in the samples which had not received any 15N fertilization at all. Table 9. Amount of nitrogen originating from the fertilizer at various depths in samples of the laboratory experiment (on an average 10—30 days after beginning the experiment) Taulukko 9. Lannoitteesta peräisin olevan typen määrä eri syvyyksissä laboratorio kokeen näytteissä (keskimäärin 10—30 vrk:n kuluttua kokeen aloittamisesta). Proportion of X Source of variation Total nitrogen fertilizer in the total nitrogen F F Depth 1.06 33.72*** Time of application 1.18 6. 9 6* * * Depth X time of application 0. 9 0 3.03*** Depth, cm Syvyys, cm 0 Fertilization with 1Б Х urea and irrigation (mm/day) Lannoitus lhN-urealla ja kastelu (mml vrk) 0.5 1.0 2.0 4.0 Without fertilization and irrigation Ilman lannoitusta ja kastelua 0-5 5—10 10—15 Б 1 305.8 33.6 7.0 "ertilizer nitrogen, m» Mnnoitetvvveä, mq 272.8 324.8 41.0 40.1 5.6 8.9 308.1 105.5 13.fi 311.1 187.1 32. з 33. з 13.2 5.8 Total Yhteensä 0—15 346.4 ï a 7, 75.3 ! 319.t 373.8 427.2 530.5 fertilizer nitrogen, % of the .mount used — Lannoilelyppeä, % iiytetystä määrästä 69.4 1 81.3 i 92.9 [ 115.3 52.3 11.4 35 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using IS N labelled urea . 79.2 These results indicate that in the laboratory experiment, some of the nitrogen given as urea has obviously volatilized from the surface of the peat and collected on the surface of neighbouring sample containers. In the sample containers which had received irrigation intensities varying between 0—2.0 mm/day, there was altogether 3.6 g less fertilizer nitrogen than had been applied, while in the other containers there was altogether l.i g more fertilizer nitrogen than had been applied. Volatilization has been strongest when fertilization has been carried out without irrigation, for the nitrogen can only be moved below the surface layer of the peat by irrigation. There has been either a very small volatilization loss or none at all when the samples have been irrigated strongly. 4. DISCUSSION The results of the study indicate that the thickness of the peat affected the utilization of fertilizer nitrogen by pine. Pines growing on mineral soil clearly took up more of the nitrogen from urea fertilizer labelled with 15N per unit needle dry weight than those growing on peat soil, and more on shallow peated peatland than on thick peated one. The results thus show that the need for nitrogen fertilization has decreased with increasing peat thick ness, just as has been presented in recommendations for practical forestry (e.g. H uik a r i and Paavilainen 1972). The main reason for this is that nitrogen is the nutrient which has the strongest effect on tree growth on the mineral soil in Finnish conditions (Viro 1965), while on the other hand the lack of phosphorus and potassium has the greatest effect on peat lands. When discussing factors which may possibly have affected the more efficient uptake of fertilizer nitrogen by pines growing on the mineral soil site compared to those growing on the peatlands, attention should also be payed to the root system ratios of both the trees and the ground vegetation. The results showed that there were approximately as many pine roots on all the sites studied, but there were fewer ground vegetation roots on the mineral soil site than on the peatlands. Root system competition with the ground vegetation, which strongly affects the nutrient uptake of trees (cf. e.g. Hesselman 1910, 1917, Aaltonen 1920, 1926, Björk man 1945, Björkman & Lundeberg 1971), has thus been less on the mineral soil site than on the peatlands, in which case the pines have been able to take up nutrients given by fertilization more easily. The different depth distribution of the root systems on the various sites may also have affected the utilization of fertilizer nitrogen by pine. The pine roots especially on the thick peated peatland were very superficial and although urea is strongly retained by the peat (cf. p. 32), some of the nitrogen may have been leached out of the surface layer where most of the pine roots were situated. On the other hand, it should be mentioned that it has initially been easier for the trees to take up the nitrogen given by fertilization, the more superficial their root systems have been. 37 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea .. . 79.2 Furthermore, it can be assumed that pine is generally able to take up nutrients more efficiently on mineral soil sites than on undrained peatlands, in which for instance the total air space in the peat may be so low that it is one factor disturbing the growth and action of the roots (e.g. Paavi lainen 1967, Lähde 1969). The nitrogen given by fertilization might also be bound more strongly by peat than by the humus layer of the mineral soil, thus making it more difficult for the trees to use it. The time of fertilizer application affected the utilization of urea fer tilizer by pine on all sites studied, although the effect was less on the peat lands than on the mineral soil site. The results of the experiment set up on forest covered sites showed that the trees took up less fertilizer nitrogen when application was carried out on the top of a snow cover than when fertilizer was applied onto the bare ground. In addition, the experiment on the Sphagnum fuscum open swamp showed that clearly more urea fer tilizer was retained in the ground when it was applied on the bare ground than on the top of a snow cover. According to these results, application carried out on the bare ground on peatlands gives better results as far as tree growth is concerned than application on snow, as earlier studies con cerning the effect of the time of application also show (Paavilainen 1969). When attempting to affect the uptake of fertilizer nitrogen by trees during the same growing season, the results obtained in this study show that the fertilizer should be applied before tree growth starts. A corre sponding conclusion has also been reached in earlier studies (cf. Viro 1970). As regards the uptake of nitrogen by trees, application carried out on frozen but snowless ground gave as good a result as the application done in the spring. The retention of nitrogen by the peat was in both cases approximately as great. The results also show that pine has probably not been able to take up fertilizer nitrogen when the ground is frozen, although the uptake of water is to a certain extent possible in frozen peatlands (Huikari & Paar lahti 1967, Leikola & Paavilainen 1972). The effect of nitrogen fertilization given late in the autumn or at the beginning of the winter will thus only become apparent in the following growing season. There was no significant difference between the uptake of fertilizer nitrogen by dwarf shrubs and mosses on the sites studied. This result is probably influenced by the small number of observations made, as the material in this case consisted of only one time of fertilizer application, yet there were altogether five times of application used in the pine study. The nitrogen given as urea is quite strongly retained by peat. Even when an irrigation intensity corresponding to very heavy rain was used, only a very small amount of the fertilizer nitrogen leached deeper than 15 38 Eero Paavilainen 79.2 cm from the surface of the peat. Several earlier studies have also shown that of the various types of nitrogen fertilizers, particularly the ammonium nitrogen formed from urea by hydrolysis is retained very strongly by the litter and humus layer of forest mineral soils and by peat (e.g. Roberge & Knowles 1966, Overrein 1967, 1968, 1969, 1971 a, b, Nö m mik & Pop o vie 1971, Knowles & Lefebvre 1972, Mal colm 1972, Pop o vie & Nömmik 1972). On the basis of these results, it seems highly unlikely that nitrogen would pass into the drainage ditches or ground water if urea is correctly applied as a nitrogen fertilizer on peatlands. The laboratory experiments would indicate that ammonia formed from urea probably can volatilize from peatlands. It is obvious that the hydro lysis of urea takes place quite quickly even in acidic peat (cf. Gibson 1930) and that when urea is applied, the pH value of the soil rises locally so high that volatilization of ammonia becomes possible. It would appear that the danger of volatilization is greatest during dry or low rainfall periods when the initially damp peat dries up (cf. Ernst & Massey 1960, West ma n 1973). On the other hand, when the surface of the peatland remains wet, for instance if fertilization is followed by rainy periods, then the loss of nitrogen is probably very small. Many experimental results have been obtained for forest covered mineral soils which show that the ammonia formed from urea has been volatilized (e.g. Nö mmi k 1967, Overrein 1 968, 1969, Hiis e r 1969, Vo 1 k 1970), but results have also been presented which show that volatilization has remained low (e.g. Knowles & Lefebvre 1972, Overrein 1972). In forest covered mineral soils, the weather conditions play quite a decisive role in the volatilization of nitrogen derived from urea (cf. e.g. Viro 1972). It can be seen from the results that a pine growing on a sedge pine swamp has taken up only 2.3 % of the nitrogen given by fertilization, while the proportion in the ground vegetation was over eight times greater, i.e. 19.4 %. According to earlier studies, the relative proportion of nitrogen taken up by trees has usually been greater. N ö mmi k (1966) found that 3—9 % of the nitrogen given by fertilization was retained during two growing seasons in the parts above ground of 11—12 years old pine seedlings. According to Björkman, Lunde b e r g & Nömmik (1967), 7 % of the nitrogen given by fertilization was retained in one growing season by young pine trees, and 2—lB % by the ground vegetation. In mature stands, the utilization of fertilizer nitrogen by trees has been noticeably greater (e.g. Ta m m 1963 a, b, Popo v i c & Burgtorf 1964, Viro 1965). For instance, according to Viro (1965) the trees in spruce stands and VT pine stands took up during five years about 25 % of the nitrogen given by fertilization. 39 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using I3 N labelled urea ... 79.2 The most important reason for the differences in the results is pre sumably because a noticeably smaller amount of nitrogen was used in this study, only about 50 kg N/ha, than in earlier studies. The growth reaction of trees growing in peatland pine stands can not be very efficiently affected by such a small amount of nitrogen (Paavilainen 1972 a). In prac tice, a fertilization application of 75—100 kg of nitrogen is recommended for forest covered peatland sites (e.g. Huikari & Paavilainen 1972). The uptake of nitrogen by trees would become noticeably more efficient if competition from the ground vegetation could be eliminated. As the actual destruction of the ground vegetation for the time being has no real istic basis as far as forest economics is concerned, one possibility would be to grow the stands so dense that the amount of ground vegetation would be kept to a minimum. The addition of nutrients through fertilization is likely to make possible the growing of stands denser than would otherwise be possible on the sites in question. Single tree and strip fertilization may be possible on certain sparse pine swamp stands where the trees are small, thus limiting the unnecessary fertilization of the ground vegetation. This study was a basic investigation in which the 15N isotope technique was used. The method proved to be so useful, that further studies about many of the questions concerning nitrogen fertilization of peatland forests would seem justified. 5. SUMMARY The following points have been examined in the study: the uptake of fertilizer N, applied as urea, by pines growing on peat lands with a thick peat or shallow peat layer and on a VT site for comparison, the dependence of nitrogen uptake on the time of fertilizer appli cation and the growing season, the retention of fertilizer nitrogen by different parts of pine and the ground vegetation, and the leaching and volatilization of nitrogen given as urea in peat. Urea labelled with 15N isotope has been used in the study. Altogether there were three series of experiments, one of which was carried out on forest covered sites, one on a Sphagnum fuscurn open swamp, and one in the laboratory. Information concerning the material and methods have been presented in Tables I—3 and Figs. I—s. The results indicate that the thickness of the peat has an effect on the ability of pine to utilize fertilizer nitrogen. Pines growing on the mineral soil site clearly took up more nitrogen per unit needle dry weight than those on peat soils, and on shallow peat more than on thick peat (Table 4, Figs. 6—7). The time of fertilizer application also affected the extent to which the sample trees were able to take up nitrogen given as urea. The proportion of fertilizer nitrogen in the total nitrogen of those sample trees which re ceived urea fertilizer on snowless ground before growth started, was ap proximately twice that of the sample trees which received the fertilizer while the ground was covered with snow. The differences between sample trees fertilized at different times were greater on the mineral soil site than on the peatland sites. The nitrogen content of the needles could clearly be affected in the year when fertilization took place, if it was carried out before the onset of tree growth. As the ground was still frozen before the start of the growing season, the trees have probably not been able to take fertilizer nitrogen. 41 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea .. 79.2 6 15579—73 The nitrogen content of needles from different parts of the crown is shown in Table 5, that of the trunk and root system of pine in Table 6, and the nitrogen content of the ground vegetation in Table 7. On the basis of the analysis results and the dry weight determinations, it was calculated that altogether 65.7 % of the fertilizer nitrogen had been retained on the sedge pine swamp. The sample tree retained 2.3 %, and the ground veg etation surrounding the tree 19.4 %. The amount of fertilizer nitrogen taken up by the tree was smaller than the amount reported in earlier studies, but this may be above all due to the small amount of nitrogen used in this study (53.3 kg N/ha). The results indicated, that if competition from the ground vegetation could be eliminated, the uptake of nitrogen by the trees would become noticeably more effective. One possible way of doing this would be to grow such dense stands that the amount of competing ground vegetation would be kept to a minimum. Single tree and strip fertilization may be possible on certain pine stands on peatlands where the trees are small, thus limiting the unnecessary fertilization of the ground vegetation. The results of both laboratory and field experiment showed that nitro gen given as urea was quite strongly retained by the peat (Table 8, Figs. B—9).8 —9). It is thus obvious that there seems to be no likelihood that nitrogen would pass into the drainage ditches or ground water if urea is correctly applied as a nitrogen fertilizer on peatlands. The results of the laboratory experiment showed that ammonia formed from urea can volatilize from peat soils (Table 9, Fig. 8). The danger of volatilization seems to be greatest during rainless or low rainfall periods when the initially moist peat dries out. On the other hand, when the surface of the peatland remains wet, for instance if fertilization is followed by rainy periods, then the loss of nitrogen through volatilization is probably very small. 6. REFERENCES Aaltonen, V. T. 1920. Über die Ausbreitung und den Reichtum der Baumwurzeln in den Heidewäldern Lapplands. Acta For. Fenn. 14: 1—55. —» — 1926. On the space arrangement of trees and root competition. Journ. For. 24: 627—644. Björkman, E. 1945. On the influence of light on the height growth of pine plants on pineheaths in Norrland. Medd. Stat. Skogsförsöksanst. 34: 497—542. —»—,Lundeberg, G. & Nömmik, H. 1967. Distribution and balance of 15N labelled fertilizer nitrogen applied to young pine trees (Pinus silvestris L.). Stud. For. Suec. 48: 1—23. —»— &Lundeb e r g, G. 1971. Studies of root competition in a poor pine forest by supply of labelled nitrogen and phosphorus. Stud. For. Suec. 94: I—l 6. Brant s e g, A., Brek k a, A. & Braas t a d, H. 1970. Gjodslingsforsok i gran og furuskog (Summary: Fertilizer experiments in stands of Picea abies and Pinus silvestris). Medd. Norske Skogforsoksv. (100) 27. 5.: 539 —607. Cajander, A. K. 1949. Forest types and their significance. Acta For. Fenn. 56: 1—65. Ernst, J. W. & Mass e y, H. 1960. The effects of several factors on volatilization of ammonia formed from urea in the soil. Soil. Sei. Soc. Am. Proc. 24: 87—90. Gibson, T. 1930. The decomposition of urea in soil. J. Agric. Sei. 20: 549—558. Heikurainen, L. 1955. Rämemännikön juuriston rakenne ja kuivatuksen vai kutus siihen (Referat: Der Wurzelaufbau der Kiefernbestände auf Reisermoor böden und seine Beeinflussung durch die Entwässerung). Acta For. Fenn. 65.3: I—Bs. Hesselman, H. 1910. Studier över de norrländska tallhedarnas föryngringsvillkor. I. (Referat: Studien über die Verjüngungsbedingungen der norrländischen Kiefernheiden. I.). Medd. Stat. Skogsförsöksanst. 7: 25—68. —»— 1917. Studier över de norrländska tallhedarnas föryngringsvillkor. 11. (Referat: Studien über die Verjüngungsbedingungen der norrländischen Kiefernheiden. II.). Medd. Stat. Skogsförsöksanst. 13—14: 1221 —1286. Hoffmann, G. 1967. Jahreszeitliche Änderungen des Stickstoffspiegels in Blättern, Holz und Rinde von Robinia pseudoacacia L. (English summary). Arch. Forstw. 16: 509—514. Hu i k ar i, O. 1952. Suotyypin määritys maa- ja metsätaloudellista käyttöarvoa silmällä pitäen (Summary: On the determination of mire types especially con sidering their drainage value for agriculture and forestry). Silva Fenn. 75: 1—22. —»— 1964. Erilaisten fosfori- ja typpilannoitteiden soveltuvuudesta suometsän lan noitukseen. Leipä leveämmäksi 1964 (1): 13—17. —»— 1973. Koetuloksia metsäojitettujen soiden lannoituksesta. Metsäntutkimus laitoksen suontutkimusosaston tiedonantoja 1973/1. 43 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea 79.2 Huikari, O. &Paarlahti, K. 1967. Results of field experiments on the ecology of pine, spruce, and birch. Comm. Inst. For. Fenn. 64. l: 1—135. —»— & Paavilainen, E. 1972. Metsän lannoitus. 2. painos. Helsinki. H ü s er. R. 1969. Harnstoffumsetzung im Rohhumus. Forstwiss. Cbl. 88: 149 —159. Ivank o, S. 1972. Recent progress in the use of 15N in research on nitrogen balance studies in soil-plant relationships. In: Isotopes and radiation in soil-plant re lationships including forestry. Proc. Symp. organized by the lAEA and FAO. Vienna 1971, p. 483—497. J uusel a, T., Kaunisto, S. & Mustonen, S. 1969. Turpeesta tapahtu vaan haihduntaan vaikuttavista tekijöistä (Summary: On factors affecting evapo-transpiration from peat). Comm. Inst. For. Fenn. 67. l: 1—45. Kalela, E. K. 1949. Männiköiden ja kuusikoiden juurisuhteista. I. (Summary: On the horizontal roots in pine and spruce stand. I.). Acta Forest. Fenn. 57.2: 1—79. Karsisto, K. 1967. Eri ajankohtina annetun NPK-lannoituksen aiheuttamista reaktioista rämeen männyntaimistoissa (English summary). Suo 18: 49—55. Snowies, R. & Lefeb v r e, J. 1972. Field, greenhouse and laboratory studies on the transformation and translocation of 15N-labelled urea in a boreal black spruce system. In: Isotopes and radiation in soil-plant relationships including forestry. Proc. Symp. Organized by the lAEA and FAO, Vienna 1971, p. 349 358. Leikola, M. & Paavilainen, E. 1972. Water uptake from frozen soil. In: Isotopes and radiation in soil-plant relationships including forestry. Proc. Symp. organized by the lAEA and FAO, Vienna 1971, p. 413—417. Lähd e, E. 1969. Biological activity in some natural and drained peat soils with special reference to oxidation-reduction conditions. Acta For. Fenn. 94: 1 —69. M a 1 c o 1 m, D. C. 1972. The effect of repeated urea applications on some properties of drained peat. Proc. 4th Intern. Peat Congr. Otaniemi/Finland 1972. Vol. Ill: 451 —460. Mälkönen, E. 1970. Kuiva -ainetuotoksen ja ravinteiden jakautuminen männi kössä. Lie. thesis. Mimeographed, Department of Silviculture, Helsinki Univer sity. 97 p. —» — 1972. Hakkuutähteiden talteenoton vaikutus männikön ravinnevaroihin (Sum mary: Effect of harvesting logging residues on the nutrient status of Scots pine stands). Folia For. 157: I—l 4.1 —14. Möller. G. 1971. Skogsgödsling. Skogen 1971 (11): 360—367. 374. Nömmik, H. 1966. The uptake and translocation of fertilizer Nl5 in young trees of Scots pine and Norway spruce. Stud. For. Suec. 35: I—lB.1 —18. —»— 1967. Use of micro-plot technique for studying gaseous loss of ammonia from added nitrogen materials under field conditions. Acta Agr. Scand. 16: 147—154. —»— & Popov i c, B. 1971. Recovery and vertical distribution of 15N labelled fertilizer nitrogen in forest soil. Stud. For. Suec. 92: I—2o.1 —20. O v e r r e i n, L. N. 1967. Isotope studies on the release of mineral nitrogen in forest raw humus. Medd. Norske Skogsforsoksv. 85: 542—565. —»— 1968. Lysimeter studies on tracer nitrogen in forest soil. I. Nitrogen losses by leaching and volatilization after addition of urea-N 15 . Soil Sei. 106.4: 280—290. —»— 1969. Lysimeter studies on tracer nitrogen in forest soil. 11. Comparative losses of nitrogen through leaching and volatilization after the addition of urea-, ammonium- and nitrate-N15. Ibid. 107.3: 149—159. 44 Eero Paavilainen 79.2 Overrein, L. N. 1970. Tracer studies on nitrogen immobilization-mineralization relationships in forest raw humus. Plant & Soil 32: 478—500. —»— 1971 a. Isotope studies on the leaching of different forms of nitrogen in forest soil. Medd. Norske Skogsforsoksv. 106: 331 —351. —»— 1971 b. Isotope studies on nitrogen in forest soil. I. Relative losses of nitrogen through leaching during a period of forty months. Ibid. 114: 261 —280. —»— 1972. Isotope studies on nitrogen in forest soil. 11. Distribution and recovery of 15N-enriched fertilizer nitrogen in a 40-month lysimeter investigation. Ibid. 307—324. Paarlahti, K. 1967. Lannoitusajankohdan vaikutus rämemännikön kasvureak tioihin (Summary: Influence of the time of fertilization on the growth reactions in a pine stand on peat soil). Comm. Inst. For. Fenn. 63.4: I—2o.1 —20. —»— ,Reinikainen, A. & Veijalainen, H. 1971. Nutritional diagnosis of Scots pine stands by needle and peat analysis. Ibid. 74.5: I—sB. Paavilainen, E. 1966. Maan vesitalouden järjestelyn vaikutuksesta rämemän nikön juurisuhteisiin (Summary: On the effect of drainage on root systems of Scots pine on peat soils). Comm. Inst. For. Fenn. 61.1: I—llo.1 110. —»— 1967. Männyn juuriston suhteesta turpeen ilmatilaan (Summary: Relation ships between the root system of Scots pine and the air content of peat). Ibid. 63.6: I—2l.1 21. —» — 1969. Tutkimuksia levitysajankohdan vaikutuksesta nopealiukoisten lannoit teiden aiheuttamiin kasvureaktioihin suometsissä (Summary: Influence of the time of application of fast-dissolving fertilizers on the response of trees growing on peat). Folia For. 75: 1—24. —»— 1972 a. Reaction of Scots pine on various nitrogen fertilizers on drained peat lands. Comm. Inst. For. Fenn. 77.3: 1 —46. —»— 1972 b. Uptake of N l5 urea by Scots pine on peat soils. Proc. 4th Intern. Peat Congr. Otaniemi/Finland 1972. Vol. Ill: 521 530. Popovi c, B. & Burgtor f, H. 1964. Upptagning av växtnäring efter gödsling av ett tallbestând i Lappland (Referat: Die Nährstoff aufnähme nach der Düng in einem Kiefernbestand in Lappland). Skogshögsk. Inst. Skogsekologi, Res. notes 4: I—ls.1 —15. —» &Nömm i k, H. 1972. Use of the 15 N technique for studying fertilizer nitro gen transformation and recovery in forest soil. In: Isotopes and radiation in soilplant- relationships including forestry. Proc. Symp. organized by the lAEA and FAO, Vienna 1971, p. 359—368. Robe r g e, M. & Kn o wle s, R. 1966. Ureolysis, immobilization and nitrification in black spruce (Picea Mariana Mill.) humus. Soil Sei. Soc. Am. Proc. 30: 201 — 204. Tamm, C. O. 1955. Studies on forest nutrition. I. Seasonal variation in the nutrient content of conifer needles. Medd. Stat. Skogsforskn. Inst. 45.5: 1—34. —»— 1963 a. Die Nährstoffaufnahme gedüngter Fichten- und Kiefernbestände. Arch. Forstw. 12(2): 211—222. —» — 1963 b. Upptagningen av växtnäring efter gödsling av gran- och tallbestând (Summary: The uptake of plant nutrients after fertilizer application to spruce and pine stands). Skogshögsk. Inst. Skogsekologi, Res. notes 1: I—l 7.1 —17. —»— 1968. An attempt to asses the optimum nitrogen level in Norway spruce under field conditions. Stud. For. Suec. 61: I—3o.1 —30. V i r o, P. J. 1965. Estimation of the effect of forest fertilization. Comm. Inst. For. Fenn. 59.3: 1—42. 45 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea ... 79.2 Viro, P. J. 1970. Time and effect of forest fertilization. Ibid. 70.5: I—l 7.1 —17. —»— 1972. Die Walddüngung auf finnischen Mineralböden. Folia For. 138: I—l 9.1 19. V o 1 k, G. M. 1970. Gaseous loss of ammonia from prilled urea applied to slash pine. Soil. Sei. Soc. Am. Proc. 34: 513—516. Westman, C. J. 1973. Typpilannoitteiden reaktiot metsämaassa. Suo 24: 31—36. White, D. P. 1954. Variation in the nitrogen, phosphorus and potassium contents of pine needles with season, grown position and sample treatment. Soil. Sei. Soc. Am. Proc. 18: 326 —330. TUTKIMUKSIA TURPEEN PAKSUUDEN JA LEVITYS AJANKOHDAN VAIKUTUKSESTA MÄNNYN LANNOITETYPEN OTTOON. SELOSTE Tutkimuksessa, jonka tarkoituksena on tuoda lisävalaistusta suometsien typpi lannoituksen perustana oleviin kysymyksiin, on selvitetty: neulasanalyysien avulla männyn lannoitetypen ottoa paksuturpeisella ja ohutturpeisella suolla ja vertailua varten myös kankaalla sekä typen oton riippuvuutta lannoitteen levitysajankohdasta ja kasvukauden ajasta, lannoitetypen pidättymistä männyn eri osiin ja pintakasvillisuuteen sekä ureana annetun typen huuhtoutumista ja haihtumista turpeessa. Lannoitteena on käytetty 15N-isotoopilla merkittyä ureaa. Kun Suomessa ei ole aikaisemmin tehty metsänlannoitukseen liittyviä tutkimuksia tätä erittäin käyttö kelpoiseksi osoittautunutta isotooppitekniikkaa hyväksi käyttäen, on käsillä oleva julkaisu myös perusselvitys mahdollisia suometsätieteellisiä jatkotutkimuksia varten. Koesarjoja perustettiin kaikkiaan kolme. Niistä yksi sijaitsi metsässä, yksi rahka nevalla ja yksi tehtiin laboratoriossa. Aineistoa sekä käytettyjä menetelmiä on selos tettu sivuilla B—l9 sekä taulukoissa I—31 —3 ja kuvissa I—s. Turpeen paksuus vaikutti männyn lannoitetypen ottoon. Kankaalla puut ottivat samaa neulasten kuiva-ainemäärää kohden selvästi runsaammin typpeä 15N:llä merkitystä urealannoitteesta kuin suolla ja ohutturpeisella suolla enemmän kuin paksuturpeisella (taulukko 4, kuvat 6 —7). Neulasten kokonaistyppipitoisuus oli kankaalla alempi kuin turvemaalla. Tulokset viittaavat siihen, että typpilannoituksen tarve vähenee turpeen paksuuden kasvaessa, kuten käytäntöä varten annetuissa suosituksissa on esitettykin. Eräänä tekijänä, joka saattaa vaikuttaa männyn lan noitetypen erilaiseen hyväksikäyttöön kankaalla suohon verrattuna, on suoritettujen mittausten perusteella esitetty puiden ja pintakasvillisuuden juurten määrä ja syvyys jakautuminen näillä kasvupaikoilla. Levitysajankohta vaikutti myös selvästi siihen, kuinka runsaasti puut ottivat ureana annettua typpeä. Annettaessa urea lumettomalle maalle lannoitetypen osuus neulasten kokonaistypestä muodostui noin kaksinkertaiseksi verrattuna lumelle suo ritettuihin levityksiin. Eri levitysajankohtien väliset erot olivat kankaalla jyrkempiä kuin suolla. Lumettomaan maahan levityksessä saatiin jokseenkin yhtä voimakas vaikutus suoritettaessa levitys joulukuussa maan ollessa lumeton, mutta vahvasti roudassa, taikka keväällä ennen puiden kasvun alkamista. Annettaessa lannoitus heinäkuussa puut ehtivät ottaa varsin vähän lannoitetyppeä lannoitusvuoden aikana. Männyn neulasten kokonaistyppipitoisuus oli toukokuun puolivälissä koko aineiston mukaan keskimäärin 1.04% ja aleni kesäkuun puoliväliin mentäessä 0.9 2 %:iin. Uusien lannoitusvuotena muodostuneiden neulasten pitoisuus oli korkeim millaan heinäkuussa (1.3 4%), aleni tämän jälkeen elokuussa, mutta nousi jälleen 47 Studies on the Uptake of Fertilizer Nitrogen by Scots Pine using 15 N labelled urea .. . 79.2 syksyllä. Lannoitetypen osuus neulasten kokonaistypestä oli toukokuun ja kesäkuun näytteissä varsin pieni, vaikka lannoite annettiin ennen kasvukauden alkua. Heinä kuussa lannoitetypen osuus lisääntyi selvästi. Keski- ja loppukesällä neulasten sisäl tämän lannoitetypen osuuden vaihtelu oli samansuuntainen kuin kokonaistypenkin vaihtelu. Männyn latvuksen eri osissa kasvaneiden eri-ikäisten neulasten typpipitoisuus on esitetty taulukossa 5, rungon ja juuriston taulukossa 6 sekä pintakasvillisuuden typpipitoisuus taulukossa 7. Analyysitulosten sekä kuivapainomääritysten perus teella laskettiin, että 65.7 % annetusta lannoitetypestä oli pidättynyt suursararä meellä koepuuhun, pintakasvillisuuteen ja maahan. Koepuun osuus lannoitetypestä oli 2.3 % ja pintakasvillisuuden osuus 19.4 %. Puun ottaman lannoitetypen määrä oli pienempi kuin mitä aikaisemmissa tutkimuksissa on yleensä esitetty. Tämä joh tunee etenkin käytetyn typpimäärän pienuudesta (53.3 kg/ha N) sekä siitä, että tut kittiin varttuneita puita. Puiden typen otto tehostuisi huomattavasti, jos voitaisiin eliminoida pintakas villisuuden kilpailu. Kun pintakasvillisuuden suoranaiseen hävittämiseen ei ainakaan tällä hetkellä ole reaalisia edellytyksiä käytännön metsätaloudessa, on eräänä mah dollisuutena pidettävä puuston kasvattamista niin tiheänä, että pintakasvillisuuden määrä jää vähäiseksi. Ravinteiden lisääminen lannoituksella antaneekin mahdolli suuden kasvattaa puusto tiheämpänä kuin mitä ko. kasvupaikalla muuten tehtäisiin. Harvassa rämepuustossa ja pienten puiden ollessa kysymyksessä olisi kaikesta pää tellen aihetta käyttää puukohtaisia ja kaistalannoituksia, jolloin ei turhaan lannoi tettaisi pintakasvillisuutta. Sekä kenttä- että laboratoriokokeen tulokset osoittivat, että ureana annettu typpi pidättyy varsin voimakkaasti turpeeseen (taulukko 8, kuvat B—9). Kenttäkokeen mukaan typen pidättyminen oli paljaan maan levityksissä huomattavasti voimak kaampaa kuin lumelle levitettäessä. Tämä osoittaa yhdessä jo aikaisemmin esitetty jen koetulosten kanssa, että urean levitystä paljaalle maalle on pidettävä turvemailla metsän kasvatuksen kannalta edullisempana kuin levitystä lumelle. Laboratoriossa turvealustalla tehty koe osoitti, että erittäin runsasta sadetta vastaava kastelukin sai vain hyvin vähäisen määrän lannoitetypestä huuhtoutumaan 15 cm:ä syvemmälle. Näiden sekä kenttäkokeen tulosten perusteella onkin ilmeistä, että käytettäessä suon typpilannoituksessa ureaa ja suoritettaessa lannoitus teknilli sesti oikein, ei ole sanottavaa pelkoa siitä, että typpeä joutuisi ojastoihin tai pohja veteen. Laboratoriokokeen perusteella on pidettävä mahdollisena, että ureasta muodostu vaa ammoniakkia voi haihtua turvemaasta (taulukko 9, kuva 8). Haihtumisen vaara näyttäisi olevan suurin sateettomana tai hyvin vähäsateisena aikana alunperin kos tean turpeen kuivuessa. Sen sijaan suon pinnan pysyessä märkänä esimerkiksi lannoitusta seuraavan sateen vaikutuksesta typen haihtumishäviö on todennäköisesti varsin pieni. AN ENERGETIC MODEL LINKING FOREST INDUSTRY AND ECOSYSTEMS JAMES Р. CUNNINGHAM SELOSTE METSÄTEOLLISUUDEN JA EKOSYSTEEMIEN VÄLISEN VUOROVAIKUTUKSEN ENERGIAMALLI RÉSUMÉ КРАТКОЕ ИЗЛОЖЕНИЕ HELSINKI 1974 ISBN 951-40-0081-1 Helsinki 1974. Valtion painatuskeskus Preface This report presents the first results of an ongoing project intended to quantify certain relationships between industry and ecosystems. The forest products sector is first described within the frame of the national economy of Finland. A theoretical foundation is developed for synthesizing economic and ecological methods in the study of interactions between human activities and the environment, and these principles are then applied to a model of the wood-using industries. Finally, an account is given of empirical work undertaken to describe and test the correspondence between economic and ecological formulations of industrial production, with particular emphasis on paper manufactures in Finland. A number of persons in the Forest Research Institute and in other branches of the Finnish government have assisted me during the course of the project. Especially I must acknowledge Professor Lauri Heikin heimo, who seems never to tire in his commitment to maintaining the best possible climate of work for every one under his supervision. Professors Pentti Hakkila and Kullervo Kuusela and Mr. Reino Hjerppe reviewed the manuscript for publication, as did Professor Pentti Malaska. Their comments on fundamental issues of the study were particularly constructive. Mr. Olli Nissilä has repeatedly extended himself to untangle the numerous small problems of a stranger to his land. Helsinki, August 1973 James P. Cunningham CONTENTS Page 1.0 The study system 5 2.0 Theoretical foundations 7 2.1 Ecology and energy 7 2.2 Industry and energy 10 2.2.1 Growth and development 13 2.2.2 Capital theory 14 2.2.3 Technological change 14 2.2.4 Cost-benefit analysis 15 3.0 An integrated Industry Ecosystem Model 18 3.1 Physical linkages 18 3.2 Practical goals 23 4.0 Exploratory empirical work 24 4.1 Premises 24 4.2 Data 24 4.2.1 Content 24 4.2.2 Availability 26 4.2.3 Classification 26 4.3 Analysis 31 4.3.1 Output-input ratios 31 4.3.2 Production functions 32 4.4 Interpretation 36 5.0 Conclusions and program of further work 39 Literature cited 40 Appendix 49 1.0 THE STUDY SYSTEM In Finland the forest-based industries support a major share of the national economy, in 1969 accounting for some 24 % of total industrial out put, and 58 % of vital exports (32). In turn, the forest industries are domi nated by papermaking, which comprised about 75 % of the output in this sector. As in most other technologically advanced nations, public and private groups in Finland now face certain problems associated with maintaining a desired level of economic growth. Foremost among these is the growing scarcity of raw materials and power sources to support industrial expansion. In the forest industry sector, the MERA program (15) represents a vigorous and comprehensive effort to expand the raw-material base, undertaken by Finnish government and industry with international backing in the form of a World Bank loan. Although the outcome will depend to a large extent on the willingness of private landowners to invest in timber production, the goal is to increase allowable drain by over 50 % from 1973 to 1957, with even greater gains in succeeding periods. A state power company (9) pro jects power use from all sources also to increase by half in Finland during the next ten years. In these forest-products industries there is a close and -perhaps unique relation between the raw material and the power for processing it. Wood in various forms has been heavily used in this country for heating of homes and other buildings and for the generation of industrial power. Basic studies (28, 29) of this utilization have been conducted by the Forest Research Institute. Demands for raw material have encouraged reduction of the proportion of wood which is used as fuel, while increasing power requirements have given birth to technologies such as that of the recovery boiler for generating power from papermaking residues. The tradeoffs between these utilization alternatives for wood are inherent in the material, which now can be rather easily converted into food as well (27). Even in 1969, wood supplied well over half of the fuels used in the paper industry, and more than a quarter of those for the whole industrial system. The earlier signi ficance of this source of power can be inferred from the official industrial 6 James P. Cunningham 79.3 statistics (35): as recently as 1963, all fuels used by industry were converted into equivalent volumes of »piled pine firewood»! At the same time certain adverse effects upon natural systems, as well as upon the quality of human life, are engendered by the securing and industrial processing of raw materials and power, and by the consumption of the goods and services thus produced. In Finland as elsewhere, it is recognized (23, 32) that the real standard of living is incompletely measured by the goods and services customarily accounted as national income. Certain »discommodities» have to be measured as well, if we are to obtain accurate measures of income and welfare. In the forest industries, these include the aesthetic losses sometimes associated with timber harvesting, as well as pollution of waters and the air. As we proceed, it will be seen that certain features of these apparently disparate costs can be measured in the same way that we measure production. 2.0 THEORETICAL FOUNDATIONS » hut those are all only symptoms of our rather lavish consumption of energy.» That remark by my long-time teacher and friend John Duffield, a silvi culturist, came as the wry response to a rather diffuse declaration of interest in studying »environmental problems—pollution, pojralation growth, and things like that». The conversation (4) provided a gell for ideas gathered from diverse sources, and later a focus for this study. In all industrialized countries, economic decisions are made by market mechanisms operating within a framework of governmental requirements and restrictions. Whatever may be the differences in institutional systems, the effectiveness of economic decision making cannot exceed the quality of the information available to planners. To accurately assess the net con tribution of the wood processing industry to national income and wealth, we need some common measures for activities as diverse as the planting of trees, the cooking of wood pulp, and the life processes of fresh-water bacteria. This is a large order, and no one approach can be satisfactory by itself. 2.1. Ecology and energy I propose that we can significantly augment both the scope and the accuracy of useful economic data by borrowing some of the techniques of quantitative ecology. Now, »ecology» has lately become a slogan word inspiring devotion, fear or amusement, depending on the vantage point from which you view the various cross-fires of the current environmental crusade. The association is made almost inevitable by the fact that some of the leading scientists of this discipline are also foremost among the cam paigners. This movement is largely motivated by a perceived need for better means of directing a system, the industrial state, judged by many to be out of control in certain important respects. The most evident symptom is the current exponential growth of population and production, with atten dant depletion of resources, which seems likely to over-run the carrying 8 James P. Cunningham 79. s capacity of the terrestrial biosphere within a few decades, or generations at most (14, 19). In the last few years there have been encouraging signs that these systems may be self-regulating: in Finland and in the United States, for example, the rate of population growth has slowed quite dramatically in the former (34). However, from past experience it is likely that these demographic adjustments are transitory, and in any case it does not neces sarily follow that there will be any slackening of the upward pressure on national incomes generated b}7 demands for higher standards of living. It can be disheartening to see to what little effect cautioning voices are raised. Mill's (17) discourse »Of the Stationary State» might as well have been written for our century as his. Let us consider briefly some features of ecological science, to discharge the emotional content of this term. Although many biologists are raising these warnings that human survival may be endangered, it is paradoxical that in their science the survival of an organism is interesting only with respect to the adaptive information it passes on to the population, and even the disappearance of whole species can often be viewed as ordinary adjust ments in a dynamic system. Their approach to behavior is evolutionary: an organism's response to a particular stimulus is conditioned by the sum of successful responses over many generations. Appropriately, the notion that a lower organism acts in a certain way because it feels a need to do so is dismissed as teleology. Thus it is not to be expected that the methods of economics will be supplanted by those of ecology in dealing with these problems: the models of the latter contain no provision for deliberate decision making. However, in its empirical methodology there is much which is useful to the resource economist. Ecology is a comparatively young science, the term »ecosystem» having been introduced by A. G. Tansley less than 40 years ago (33), although the concept predates his work. It comprises elements of taxonomy, genetics, physiology, population dynamics and community interactions. The study of bioenergetics has become a major unifying principle, roughly in the last decade, although there were seminal studies as early as 1922. Engelman (5) gives a thorough review of this development as it relates to terrestrial studies. It has been demonstrated that there are regular relationships between the energy received by organisms, their photosynthesis and/or respiration, and the living matter they embody. Furthermore, these func tions can be used to predict the development of communities of different species. Many ecosystems are fully as complex as human societies, and present equally unmanageable complexity if described as natural history. The bioenergetic approach enables the major elements of these systems to 79.3 An Energetic Model Linking Forest Industry and Ecosystems 9 2 16030—73 Figure 1. Food chain showing transfers of materials and energy. This is one of the shortest and simplest food chains in which man participates. In remote parts' of Lapland some Samish people still rely almost entirely on the reindeer although most have some contact with industrial societies. In the ecosystem pictured, man is really a part of nature because his numbers and activities are circumscribed by the solar energy captured by plants and concentrated by these animals which both serve as food and provide transportation. be represented according to principles as simple as the laws of thermodyna mics. Figure 1 presents such a model, of a sort which by now is familiar to most secondary school students. Each element in this system can be repre sented as a flow or storage of energy. The intensity of sunlight is easily meas ured. The energy content of fuels and food is gauged by dehydrating and burning them, recording the amount of heat generated. At each transfer of energy from one organism to another, some energy is lost as lieat, some is used to perform work, and some is again stored as structure, becoming part of the receiving organism's body. Ultimately all of the energy will be dissipated in heat. We can speak of the efficiency of converting received energy to 10 James P. Cunningham 79.3 biomass, and the ratio of energy flow to biomass is often used to compare different communities of organisms. Indeed, certain primitive human ecosystems one may as well say economic systems have been satisfactorily described in this way. Rappa port (25) details the energy flows and storages in the agriculture practiced by the Tsembaga tribesmen of New Guinea, and concludes that this simple system is »elegant» in that it provides a very large food-energy income to the farmers, compared to the energetic cost of their labor. Kemp (10) has similarly described the hunting activities of Baffin Island eskimos. In contrast to the tropical farmers, their energy sources also include gasoline. Not all foresters who were trained more than ten years ago are familiar with the language of energy studies, but they are surely conversant with the concepts. The productive potentials of woodland ecosystems are a primary concern of this profession. For every latitude and climate there is a certain amount of solar energy which reaches the earths' surface. The amount of wood which can be harvested from a given area is determined by this sunlight, the efficiency of different trees in converting it to stored chemical energy,* and the work directed by the forester also an energy input. The main purpose of silviculture is to improve the effectiveness of this energy conversion, and yield studies are measurements of the result. 2.2. Industry and energy Elementary texts in economics present circular flow models of industry such as Figure 2 a, in which physical transfers between producers and consumers are governed by equivalent flows of money in the opposite direction. Setting aside the payment cycle for the moment, and elaborating slightly on the material flows, we have figure 2 b. The materials lost as industrial pollution and consumer wastes are all potentially recoverable: some are reconcentrated by natural processes, others command sufficiently high market prices to ensure their recovery. Others, such as toxic substances, may have no value for re-use, but containment is mandated to avoid in curring the damage costs of release. Finally, some materials may be allowed * The process of photosynthesis, common to all green plants. Still imperfectly understood, the reac tion can be verbally expressed as: water + carbon dioxide —> glucose + oxygen. This conversion is performed by sunlight in the presence of enzymes associated with chlorophyll. Thus plants provide oxygen and food for all other life. The sugar produced in photosynthesis can be meta bolized directly, or provide energy and structural components for other kinds of organic com pounds. Cellulose, the major constituent of wood and currently the one of greatest economic value, is a long-chain molecule or polymer built of simple sugar monomers. So-called plant nutrients such as nitrogen, phoshorus, and potassium may serve as catalysts and enter the structure of certain molecules, but they are not really food. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 11 Figure 2. Physical counterparts of the economic process. The simple circular-flow model economy presented in (a) is modified first to show materials cycles and then energy flows. 12 James P. Cunningham 79.3 to dissipate because they appear to have no further usefulness and no damaging potential. It must be noted that this last category includes many things which have high potential usefulness, but current market conditions are such that alternative sources of supply are less expensive. Palo (23) explores this problem of material loss and recycling with particular refe rence to the paper industry. Then there are the corresponding energy flows presented in Figure 2 c. A distinguishing feature is that these flows are all one-way: each transfer is accompanied by some loss into heat, often very great, and once lost energy is not recoverable. Georgescu-Roegen (6) builds a case for applying this universal physical entropy law to economic activities. As he and Odum point out, all work is by definition an expenditure of energy, and the develop ment of modern industrial society has been due not so much to a sudden flowering of human inventiveness as to the exploitation of fossil fuels coal, oil, and gas. This view is reinforced by empirical data presented by Cook (2) and by Singer (30). In cross section comparison of several countries, they find linear relationships between energy use and state of economic development, measured as GNP per capita. Along the same lines, A. J. Grayson (7) suggests that »Energy = g-cm sec- 1 which is the same as money, as paid to labour for example, or as incorporated in fixed capital». Similarly, Odum treats money transfer as an information feedback system which stimulates and channels »upstream» energy flows. This is equivalent to the economic notion that the existence of profits guides allocation of resources and expansion of industry in competitive markets. Recalling the three ends of energy flows in natural systems work, structure, and lieat it is clear first of all that these fully apply to industrial activities in their precise physical definitions. Then some parallels with economic concepts become apparent. For example: Variable costs are equivalent to the work done directly in manufacturing a product Fixed costs are energetic »overhead» which is used to create and maintain structure, i.e. capital equipment and the human organization Efficiency can be measured as that fraction of received energy which performs useful work, compared with the proportion of heat lost. There are four areas of economics which seem particularly likely to benefit by adopting the methodology of energetics: <9.3 An Energetic Model Linking Forest Industry and Ecosystems 13 2.2.1. Growth and development Practitioners and theorists of economic development are concerned with achieving the preconditions sufficient for a »take-off» into sustained economic growth, usually measured in terms of increase in gross national product. Activities toward this goal are directed to labor and capital inputs: on the one hand, education, labor mobilization and entrepreneurial incentives; on the other, creation of infrastructure and attracting investment funds. Employment and investment questions are also foremost in the manage ment of mature industrial economies. Energy requirements have not been ignored in practice, but regarded as a fairly minor item among the inputs required by the labor-capital machine. Energetic formulations have not entered into formal economic growth theory at all, even though they are occasionally used in econometric estimation. The reasons for this neglect are not difficult to find: until recently, the costs of energy from fossil fuels have generally reflected only the expenses of finding, mining, transporting and refining them, perhaps with some royalties to the owners of land where they are found. The money cost of energy from this source has heretofore been very small, and not at all related to the work potential of the fuel. Energy itself has thus been treated as a virtually free good in economic analysis, its physical importance notwithstanding. Recent events suggest that the time when we could do this is at an end. An OECD document (20) reveals a certain com placency with regard to energy supply among senior national and interna tional officials, even in the mid-sixties. The Energy Committee was then concerned about how certain predicted energy surpluses could be absorbed by international markets. In the few years since warnings of an impending »energy crisis» were raised by a few scientists, this concern has gone through the usual wave of popular journalism and now appears as hard reality. Natural gas reserves in the United States (which uses some 35 % of the world's energy) have been depleted to the point that in some parts of that country it is impossible to get new service connections. Shortages of electric power requiring »brownouts» have become chronic. In the spring of 1973, petroleum demands so far outran supplies that many service stations (42) and even municipal transportation systems (3) literally ran out of gas. This short-run shortage could perhaps be viewed as a problem in refinery capac ity or even business collusion, but it is taken officially as symptomatic of a long run problem: The government has ordered reductions in its own energy consumption, and established a special agency to deal with energy policy (38, 39). At the same time, the oil-producing nations of the Middle East have begun what is expected to be a massive increase in petroleum 14 James P. Cunningham 79.3 prices (43). Energy use has been thrust into the concern of economic plan ners, and the theories of economic growth ought to take account of this primacy. A remarkable reflection of the rapid evolution of official thinking is Oilers (41) assumption that »The rising prices of fuels are expected to influence not only the structure of energy consumption but also the industrial structure. Scarcity of energy would favour labour intensive production and might even become an obstacle for growth in the future.» 2.2.2. Capital Theory Capital accumulation, capital/output ratios and capital/labor ratios are major components of economic growth models, but difficulty in measuring this input has presented perhaps the greatest obstacle to empirical imple mentation of these theories. Problems of obsolescence and of adding unlike items of equipment are particularly intransigent. It is interesting to note that the notion of measuring capital in labor-units enjoys periodic revival in the literature (26), although Solow (31) makes the point that this has a »faintly archaic flavor» and brings us no closer to solving the empirical problem. This approach becomes irrelevant in view of the fact that, in Fin land for example, even by a generous estimate the energy contributed by labor to physical work performed is less than one-half of one percent see Figure 6. The work of Niitamo (17) presented a fresh approach to the problem, by using some partial power measures use of electricity and machine capacity as indicators of the use of capital. Although I have added together all of the major sources of energy for industry, this aspect of the present work differs from his not so much in content as in point of view: it now seems more reasonable to treat capital as a valve channelling disordered flows of energy to useful purposes, as in Figure 3. It may indeed be impossible to find a satisfactory common measure for valves of different designs and ages, made of different materials. But it is not quite so difficult, and for many purposes should be more useful, .to measure the flow through the valve and the leakage around it. 2.2.3. Technological change Again in growth models especially, the measurement of technological change presents problems, partially related to capital. There are also formula- 79.3 An Energetic Model Linking Forest Industry and Ecosystems 15 Figure 3. Capital is a valve channeling energy to perform work. Economic theory has treated labor and capital as the primary, indeed the only inputs for trans forming raw materials into useful products. While not wishing to minimize the need of providing for these factors, we can say that such a view does not conform well with the physical reality of industrial processes. Machines stand idle until power is applied, and human energy is scarcely sufficient to operate the controls. tions for technological change relating to labor, for neutral and for »disem bodied» technological change. In each case, however, the effect is of an autono mous force which increases productivity. Various indirect measures have been proposed in econometric studies, but a precise specification of just what technological change is remains elusive. A major component of any such definition ought to be increase in the intensity of energy utilization. 2.2.4. Cost-benefit analysis We have seen that if some resource, such as energy, is priced lower than its actual scarcity warrants, then the whole industrial system may expand beyond the limits which can be sustained by the resource base. In the same way, on the micro level if some of the costs of making and using a particular thing are borne by persons other than those who produce and consume it, then that product 1 will be relatively cheaper than it should be and more of it will be made and used than is socially desirable. Figure 4 illustrates an aberration of this kind in production decision analysis following Hicks' (8) principles. 16 James P. Cunningham 79.3 i. Costs fully internalized. ii. Some costs of input B are ex ternal to to the firm. Figure 4. Effect of externalities on output. The axes A and B measure quantities of two resources, inputs needed for production. In (i), the line segment ab is one of a family of so-called »budget lines», the locus of all maximal combinations of the two inputs which can be purchased for a given amount of money. The slope of this family of line seg ments is given by the relative prices of the two inputs. The curves I and II are two of a family of curves, each the locus of all minimal combinations of the two inputs which are required to produce a given amount of output. The point of tangency x locates the input combination which will produce the largest output within this budget constraint. In (ii), the line segment ab 0, the curves I and 11, and the point of tangency x 0 reproduce the situation in (i), assuming that all costs of production are paid by the firm. However, if someone outside the firm were to pay part of the costs for input B, then all of the input combinations along ab1 could be obtained for the same cash outlay, and a greater amount of output can be produced at x v This kind of thing is sometimes done deliberately, for example by govern ment subsidy to help an industry expand. At present we are concerned with another case, in which the costs are incurred involuntarily. This is often w That happens with industrial pollution: if one factory does not pay to repurify the water it uses, then those downstream who receive the same water must pay more to make it fit to use again. Then they are really paying some of the production costs for the first factory. Of course, these secondary users might be compensated for their losses, perhaps even by transferring the costs back to the firm if government taxes the polluter and uses these revenues to clean up the waters. Indeed, it matters little how these transfers •are arranged, so long as all parties are fully compensated. But before com 79.3 An Energetic Model Linking Forest Industry and Ecosystems 17 3 16630—73 pensation can be made the costs must be measured and in our example these will include some costs which are readily accountable, but other »intangibles» such as loss of enjoyment by those who use the waters for recreation. These vagrant costs externalities or spillover effects present such a difficult problem in empirical economics because they typically have no readily identifiable money value. However, some of them such as pollu tion can be measured in terms of the energy stress they place upon environmental systems. This has been a common procedure for the water shed manager and the industrial engineer for some years. Counting these energy loads as costs enables us, at the least, to quantify one additional dimension of heretofore unmeasurable environmental costs. Further, this energy accounting provides a unifying element needed for linking the forest industries and ecosystems. 3. AN INTEGRATED INDUSTRY ECOSYSTEM MODEL 3.1. Physical linkages In Finland this field is new, though Malaska (12) has called for com bining the study of natural and technological systems. A member of the Club of Rome, he is engaged (13) in the energy economy working group of the Bank of Finland. Pulliainen and Seiskari (24) have prepared a popular book on ecology and economics. The works of Palo, previously cited, and Kuusela (11) relate directly to the forest industry. Both present charts of flows and storages of both materials and energy in industry ecosystem interactions. That of Kuusela is richer in description of the compartments making up the system, while Palo's presentation emphasizes possibilities for augmenting the circular flows of materials through recycling. Such efforts may help to relieve raw-materials shortages, and to ease problems of solid waste disposal. On the other hand, the decisive limiting factors for economic growth may well prove to be energy sources, as well as the capacity of ecosystems for absorbing the application and dissipation of concentrated streams of energy. In Figure 5 a we have the forest and lake ecosystems characteristic of the Finnish countryside, viewed as though there were no human component. Biomass production and respiration are limited by the availability of energy from the sun, and they are in dynamic equilibrium. This does not exclude the possibility of some long-term changes taking place, however. The forest may be colonized by new species, old ones may be removed by parasites. In northern climates especially, conditions are frequently such that there is a gradual accumulation of dead organic matter, as explained by Viro (37). The lake may gradually eutro-phy * as nutrients and organic material * This enrichment causes increased primary production, typically first in the form of phytoplankton and algae, and increased biomass and respiration of all components of the lake ecosystem. The oxygen content at the bottom may fall to zero due to the activity of bacteria, and growth of rooted vegetation at the shoreline is encouraged. In this way the lake may gradually fill in by accumulation of organic matter and other sediments, and colonization by land plants (40). Shallow lakes with slow circulation conditions which typify Finnish lakes are especially susceptible to these changes if sufficient nutrients become available. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 19 are washed into it from the land. However, these processes are so gradual that they may be perceptible only over many hundreds of years. Figure 5 b introduces the forest industry let us say a paper mill as a dynamic element in the system. All of the human activities of the industry are directed to converting and exporting from the forest as much of its primary production as possible. To illustrate how the elements of this system can be quantified, I have calculated the energy value of commer cial fellings (16) in 1969. In that year about 35.3 million solid cubic meters of wood were felled. Converting these to approximate piled volumes and using the energy conversion factors for firewood from the Finnish industrial statistics, we find the energy stored in this wood is on the order of 81 million gigacalories or 94 million megawatt-hours. To put this quantity in perspec tive, it is some 9 % greater than the net energy use of all Finnish industry in that year. It must be recognized that it is usually not possible to increase the primary production of the forest, the transformation of sunlight into biomass, although we can contrive to convert a larger proportion of this into usable wood. With forest management operations, we bring in other energy sources to supplement that of the sun. If we are able to take more wood from the managed forest, it is because we direct technological work to perform some activities (regeneration, thinning, selection of superior genotypes) and control others (insects, diseases, fire), all of which drain energy from the unmanaged forest and subtract from the sum of standing -crop biomass produced. In these circumstances the trees are grown partially by the oil which powers our machines, as well as by the sun. Especially at the mill, there are other consequences of this new input of energy. All of it must be dissipated as heat, and much of this will occur at the mill site. If heated water is discharged into a comparatively small body of water, it may cause changes in the communities of organisms living there. The air will also be warmed in the vicinity of the mill. This may not be important if the plant is isolated, but in industrialized regions can cause measurable changes in the local climate. Often these changes may not be large and they may not be harmful, but they do occur. Concerning pollution, we will make one restriction: at present we will not consider discharges of toxic chemicals. The combined influences of costs and law can be expected to mandate a high degree of containment and recycling of these, at least in new mills. In paper production, a large share of the potential toxins are valuable chemicals which are customarily recovered for re-use. 20 James P. Cunningham 79.3 Figure 5a. Forest and lake ecosystems in natural linkage. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 21 Figure 5b. Forest and lake ecosystems linked with wood-using industry. 22 James P. Cunningham 79.3 In a paper mill which is relatively clean of toxins, there are two major components of water-borne effluent: suspended organic solids and »color» (22). Both exert influences on the water ecosystem which are measurable in energetic terms. The stains, besides being aesthetically objectionable, reduce the penetration of light into the water. This tends to reduce the plant life at lower depths, thereby hastening the depletion of oxygen. The organic matter provides a source of food for aquatic organisms. The effect is to create conditions paralleling those of a naturally eutrophic lake, but greatly intensified. When the eutrophication process, which might have taken thousands of years (if it occurred at all) is collapsed into a few decades (21) there are clearly visible adverse affects. The water becomes murky and smells foul; fish and other wildlife disappear, leaving only lower organisms; and in some cases there is danger to public health by proliferation of pathogenic micro organisms. There is evidence (36) that many of Finland's waters are on their way to this condition, with some 15 % of watercourses receiving effluents and 16 % of lakes in an eutrophic state, although the latter figure probably includes some naturally eutrophic waters. The wood processing industry contributes a very large proportion of this pollution, 73 % of the total volume from all sources in the country and 84 % of the biological oxygen demand.* Table 1, taken from the first Finnish yearbook of environ mental statistics, displays the sources of pollutants entering the waters of Finland in 1970. Table 1. Waste water loading of Settlement and Industry by water courses in Finland in 1970. This is expressed as BOD 5 , kilograms of oxygen equivalent to 6 days' consumption by micro organisms in metabolizing the organic pollutants. It is a standard measure in water quality studies and is directly related to the energy content of pollutants. Quantity BOD 5/day Nitrogen Phosphorus m 8/day kg/day kg/day Settlement 783 000 127 600 21 100 5 680 Foodmanufacturing 398 000 40 000 2 300 880 Manufacturing of chemicals . . . 360 000 2 500 11 500 870 Mining and quarrying 44 000 300 50 5 Manufacturing of metal products 481 000 1 400 100 15 Manufacturing of leather and leather products 5 000 10 000 800 130 Manufacturing of wood and paper products 5 620 000 989 200 11 700 2 170 Manufacturing of textiles 26 000 2 600 150 60 Total 7 717 000 1 173 600 47 700 9 810 79.3 An Energetic Model Linking Forest Industry and Ecosystems 23 Viewed as ecosystems, conditions in a managed forest are strikingly similar to those in an eutrophic lake. Biomass production is increased, species diversity is diminished, and stability- as evidenced, for example, by resistance to pathogens declines also. Of course, the increased produc tion and the elimination of undesired species are deliberate goals in forest management, whereas the same things occur »accidentally» in the lakes. But regardless of intent, it is the inf lux of an artificial source of concentrated energy which has affected both of these natural systems, and it is not sur prising that they respond in similar ways. Indeed, this is a classic pattern followed by communities of organisms which receive large imports of food. 3.2. Practical goals We are now in a position to phrase the purposes of this project rather precisely in energy terms. Broadly, it is to provide private and public planners with information which will assist them in increasing the energetic efficiency of the forest products industry. This could enable them to maintain relatively high levels of output, while reducing the energetic stress which this industry currently places upon land and water ecosystems. This in turn would enable people to enjoy the amenities of cleaner waters and less disturbed woodlands, while reducing the sacrifice of real product necessary to make this possible. The key to this prospect is the physical interdependence between tree growth, industrial processing, and pollution. Recognition of these linkages is vital to a successful solution. For example: if pollution is simply contained, its disposal may increase the energetic (and monetary) costs of processing, as well as requiring that an even greater stress be placed upon the forests, to increase wood production and hold down the costs of raw materials. However, the wood constituents comprising the pollutants can potentially be used, either by inclusion in products for sale, or as additional sources of power for processing. In the first case, the need for »virgin» raw materials is reduced; in the second, the industry's dependence on external, purchased sources of energy is reduced. Viewed in this light, the aim of this work is industrial cost reduction. If there is a new contribution to be made, it is to improve the information needed to achieve these savings, and to better perceive the similarities between problems which may at first appear quite different. The energetics of each of these processes forestry, industry, pollution are well understood by groups of specialists. What is proposed here is a relatively simple further extension, recognizing and measuring the dynamic linkages among all three elements. 4. EXPLORATORY EMPIRICAL WORK 4.1. Premises The intent here is to establish some justification for employing the methodology proposed to synthesize economic and ecological studies. Therefore this phase takes in the whole industrial system of Finland, in aggregate and by sectors, although emphasis is placed on the wood-using industries. Broadly stated, the hypothesis to be tested is: That flow of 'physical energy determines the generation of monetary value in industry. However, the inverse proposition, that economic value guides the flow of energy, is of much greater interest from the viewpoint of regulating the physical system. We investigate similarities and differences between some economic models, and counterparts constructed for energy variables. Disparities between the results obtained with the two classes of models will be no less interesting than points of agreement, for it is precisely the area of incomple teness in the monetary value system which we wish to describe. Looking only a little beyond the scope of the analysis presented here, it is expected that instances of marked divergence between money and energy costs will serve to identify the existence of some kinds of externa lities. Then, tracing the energy flows should help to place the incidence of real costs. Finally, it is to be hoped that planners will thereby be better able to rectify some of the disparities. 4.2. Data 4.2.1. Content These are the data employed in measuring the variables and estimating the parameters of the models: L = Man-hours worked per year Source: Industrial Statistics of Finland 79.3 An Energetic Model Linking Forest Industry and Ecosystems 25 i 16630—73 K = Fixed capital of industry, deflated by indices of construction costs and machinery production prices,* in thousands of Finnmarks Sources: Crude data Industrial Statistics of Finland. Indices Statistical Yearbook of Finland Q, = Output taken as value added in manufacturing, the standard definition modified by adding back in the purchase costs of energy consumed in the form of fuels, electricity, steam and hot water: deflated by production price indices; in thousands of Finnmarks Sources: Crude data Industrial Statistics of Finland. Indices Statistical Yearbook of Finland E = The theory adopted here requires that the energetic equivalent of value added should be a measure of all ivorh done in manufacturing a product, including maintenance of the productive system; total energy use in megawatt-hours. As a first approximation, the energy flows added are: a. Water power including electric power generated by water tur bines, plus power developed by similar engines harnessed directly to machines, the latter quantity estimated by the formula: in which WE = Electricity generated by water power wte = Water turbines driving electric generators wtd = Water turbines driving machines directly b. Fuels used — primarily wood in various forms, oil, and coal, with several other minor sources including peat. c. Net electricity used use minus production, a negative value for the industrial aggregate reflecting supplies to final demand sectors. d. Net steam and hot water used - use minus production. e. Human metabolic energy selection of an appropriate measure here poses certain conceptual problems: should it be only the energy expended in performing productive work? The 24-hour metabolic requirement of the worker? Or perhaps the requirements of his fam ily as well? As a first approximation, a 24-hour metabolic require ment of 3 000 kcal. for an active healthy adult has been divided by 8 working hours, and the result multiplied by the number of man hours worked per year. In any case, this measure is unlikely to affect significantly the results obtained, since the magnitude is something less than 0.5 % of total energy used. * The entries in the official statistics are fire-insurance or self-risk values. It seems reasonable to assume that these are closely related to replacement costs; hence the choice of indices. wtd • WE wte 26 James P. Cunningham 79.3 4.2.2. Availability There are certain data lacks of a more serious nature, however. More detailed work will require measures of efficiency of conversion of one form of energy to another, and of efficiency of applying energy to perform useful work: in each case, the proportion of the energy which is lost as unuseful heat. To adequately describe the system relationships, we would also need a set of accounts describing intersectoral energy transfers. Such information, perhaps cast in the form of input-output tables, would provide a better measure of total energy costs of producing a good, by adding indirect costs to the direct ones already measured. In spite of these problems, data are available for Finland from 1954 permitting a rather good aggregate estimate of energy used by industry, although there are still certain inadequacies when individual industries are considered: chief among these is the omission, until 1965, of information on the production and consumption of energy in the form of steam and hot water, a major item for some sectors. Since 1965, the energy data are good enough to warrant cross-sectional analysis for Finland. As might be expected, the measures of labor, capital and output needed for economic models are sufficient throughout the study period. 4.2.3. Classification Time period: annual data for the 16 years from 1954 to 1969 have been studied. Industrial sectors: in the analysis of this report, 26 sectors have been recognized, the code numbers * corresponding to those in the Industrial Statistics of Finland: Finnish Gmups r No Activities Included 12 Mining and quarrying 14 Stone quarrying, sorting of gravel and sand 15 Other mineral quarrying 16 Digging and preparation of peat 20 Food manufacturing industries, except beverage industries 21 Beverage industries 22 Tobacco manufactures 23 Manufacture of textiles * As of 1969, corresponding in most cases to ISIC group numbers. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 27 24 Manufacture of footwear, other wearing apparel and made-up textile goods 25 Manufacture of wood and cork, except manufacture of furniture 26 Manufacture of furniture and fixtures, except manufacture of metal furniture 27 Manufacture of paper and paper products 28 Printing, publishing, and allied industries 29 Manufacture of leather and leather products, except footwear 30 Manufacture of rubber products 31 Manufacture of chemicals and chemical products 32 Manufacture of products of petroleum and asphalt 33 Manufacture of non-metallic mineral products, except products of petroleum and coal 34 Basic metal industries 35 Manufacture of metal products, except machinery and transport equipment 36 Manufacture of machinery, except electrical machinery 37 Manufacture of electrical machinery, apparatus, appliances and supplies 38 Manufacture of transport equipment 39 Miscellaneous manufacturing industries 51 Electricity, gas and steam services 52 Water supply Further disaggregation of these statistics is possible as well: In the wood processing and paper industries (sectors 25 and 27), of particular interest to us, 27 subsectors are recognized. All of the kinds of information used thus far in this study, except value of fixed capital, are recorded to this degree of detail in the published statistics or can be derived from them by simple transformations. Of course the confidence of estimates declines as smaller sectors are examined, but these will be helpful in tracing system linkages. Figure 6 describes by source the energy used in the paper and wood processing industries, in comparison with the aggregate of all Finnish industry. It is particularly important to realize that virtually all domestic energy sources hydropower, wood derivatives, even peat are solar based and self renewing in a rather short time. In contrast, almost all foreign sources are mined products of nonrenewable fossil fuels. Hence any policies or programs which may be undertaken to reduce this source of import debits will also have the effect of helping to buffer the Finnish economy from the losses which will attend exhaustion of these resources. 28 James P. Cunningham 79.3 Figure 6a. Energy by physical sources Human work accounts for very little of the energy expended to produce goods, even in labor-intensive industries, and the share is still declining. This need not be true of service sectors. In utilizing wood, some energy savings apparently could be effected by shifting from paper toward mechanical pro cessing. Considering other forest land resources, energy scarcity also favors expansion of recreational services, particularly those generating spending by visitors from abroad. An obstacle met in preparing this figure points up data needed for structural planning to improve overall energy-output efficiency. Energy from labor, fuels, and water power can be added up straight forwardly with appropriate conversion factors. However, some sectors are powered largely by the secondary energy sources of electricity, steam and hot water produced in surplus by other industries. To fully measure the contributions of different primary sources we should add indirect uses, in the manner of preparing input-output tables. We do not as yet have such comprehensive accounts of intersectoral energy transfers. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 29 Figure 6b. Energy from fuels by type Coal supported the early industrial development of most nations and will probably be heavily utilized again as oil supplies dwindle. Because Finland has no domestic resources of coal, in this country a substantial part of the historical place of that fuel was taken by wood. In the early fifties, wood supplied about half of the fuel energy used by all industries, and more than a quarter even in 1969. Finland's reliance on this renewable fuel is certainly unique among nations in comparable stages of development even though the share of wood is currently declining rapidly, particularly in favor of oil. There have been sound technical and economic reasons for the transition, but at this juncture we might question the wisdom of further phasing out wood-based fuels. For those familiar with the technology of mechanical woodworking, it will not be surprising that waste material still supplies much of the fuel required by these mills. In contrast, burning of solid wood by the paper industry has practically ended but wood derivatives in black liquor have taken up an impressive share of fuel needs. 30 James P. Cunningham 79.3- Figure 6c. Energy by place of origin In 1954 some GO percent of the energy used by Finnish industry was of domestic origin. By 1969 this fraction had declined to about one-third. Because of changes in technology and in the composi tion of industry, and in part because of limits on water power potential the substantial economic development of this period depended heavily on expanding consumption of fuels. An accom panying substitution of imported fossil fuels for domestic wood has compounded the effect on trade. The net result has been a reversal of Finland's earlier position of relative energetic self-sufficiency, and this may prove troublesome if there is a substantial rise in world market prices of fossil fuels. Note that the wood processing industries have lagged behind others in the general swing to depend ience on imported energy supplies. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 31 4.3. Analysis 4.3.1 Output-input ratios Examining the output/energy ratios for different industries in Table 2, we find the paper industry among the lowest of all, second only to petroleum manufactures. In contrast, the output per man-hour of labor is quite high relative to other sectors. Over all sectors there is an inverse relationship between pro ductivity of labor and of energy, whereas high output/capital ratios tend to be associated with high output/energy ratios. It is worth noting as well the great variation in magnitude of the output/energy ratios. There are two main ways for the national economic planner to use this kind of intersec toral energy use comparison. First, if we should encounter a long period of rising real costs of energy it is clear that those industries with high energy requirements will be at a competitive disadvantage. Some gains in national income can be made by promoting development of less energy-intensive Table 2. Ratios of output to capital, labor, and energy in Finnish industry, 1969. Industrial Q/K Q/L Q/E sector Fmk/Man-hour Fmk/Kilowatt-hour 12 . . 0.8 5 51.38 0.9 7 14 . . 1.30 20. 2 4 0.3 7 15 . . 0.31 17. 23 0.3 2 16 . . 0. 68 9. 4 5 0. 6 0 20 . . 0. 67 23.0 6 0. 3 5 21 . . 0. 5 5 21.79 0. 3 7 22 . . 0.53 26.8 6 1.11 23 . . 0. 44 9.83 0.3 5 24 . . 1.69 8. 22 1.68 25 . . 0. 70 11.79 0.21 26 . . 0.99 8. 8 6 0.5 5 27 . . 0.32 29.19 0.0 7 28 . . 1. 1 6 16. 68 2.3 6 29 . . 0.7 9 4.0 2 0.3 4 30 . . 0.5 4 14.oo 0.4 5 31 . . 0.4 4 28.41 0.21 32 . . 0.3 6 90.5 0 0. 0 4 33 . . 0.4 9 15.22 0. 0 8 34 . . 0.3 6 23.55 0. 1 9 35 . . 0. 64 12.51 0.5 9 36 . . 0. 73 13. 90 0.7 6 37 . . 0. 78 14.97 0.9 7 38 . . 0.9 4 12.05 0. 6 3 39 . . 1.02 13. 52 0.81 51 . . 0. 40 73. 29 0. 1 3 52 . . 0. 22 62.14 0.6 3 32 James P. Cunningham 79.3 industries. Of course it is too simplistic to conclude that this is the whole answer: at the national and certainly at the international level, the inter dependence of sectors in an industrial system has to be evaluated in energetic terms also. A second, less obvious vise for such information has to do with environ mental costs such as pollution. Industries with high energy requirements are virtually certain to create intractible pollution problems. This is particularly true if we include thermal pollution in our definition. The fact is that »every thing has to go somewhere» and energy used in industry is dissipated into the environment either in the form of pollutants or as heat. A study of industrial energy requirements can thus enable the planner to form a first estimate of the probable pollution costs of alternative development strategies. 4.3.2 Production functions To examine these relationships in somewhat greater detail, production functions of the Cobb-Douglass form * (1) were compared with a family of similar functions constructed for inputs defined in energetic terms, the simplest being: * Strictly defined this class of production functions often has a + fi = 1, so that there are •constant returns to scale, but such restriction has been relaxed in this study. 1 ) Q=m L° K* 3 or log Q = log m + a log L -f- ß log K for Q = Industrial output L = Labor input K = Capital input a, ß = usually referred to as the »productivities» of labor and capital, respectively m = constant 2) Q = mE A or log Q = log m -f X log E Q = Industrial output, defined as above E = Energy consumed by industry X = »productivity» of energy m = constant 79.3 An Energetic Model Linking Forest Industry and Ecosystems 33 5 16630—73 The choice of models was guided by considerations other than conveni ence. For some years the construction of elegant and sophisticated economic models has gone far ahead of empirical testing of those models. Within this discipline the work of economic theorists has been demonstrated largely by abstract manipulations of the calculus, rather divorced from the efforts of econometricians »thrashing around in multidimensional space.» The existence of this cvirious gap, although recently narrowing, has meant that policy decisions of firms and governments are often based upon theoretical formula tions quite untried beyond the a priori reasoning of their makers. With this background, the present work proposes a certain departure from the customary economic inputs thought to be responsible for pro duction, and this distinction ought to be clearly stated. For wider commu nication of ideas, the provision of some familiar landmarks to be recognized by nonspecialist readers assumes a value which can be weighed against the pursuit of small increments in correlation. For these reasons I judged it best to employ easily calculated models from the standard toolkit of the policymaker, rather than specialized multivariate formulations of greater complexity. In addition to the primary data sets previously described, a number of other variables derived from them were tested. These included: Kt --- E/M, M being the engine capacity in kilowatts directly driving machines. This is intended as a partial measure of technology relating to capital. Lt = E/El , El being the human metabolic energy. This is intended as a measure of technology relating to labor, and is equivalent to Odum's »labor amphification factor» H = E/S, S being the energy in steam and hot water produced. This is intended as a crude first approximation of the efficiency of energy use, since S is a portion of energy input which is recovered for a second use before being dissipated. The models were tested in time series analysis for the aggregate, for the two major wood-using sectors combined, and for the paper industry. Cross -section analysis over all industrial sectors was performed for each of the years 1965 through 1969. Tables 3 and 4 present the correlation matrices of the variables used in time series and in cross-section, respectively. The corresponding data sets are found in Appendix Tables 1 and 2. Only the cross-section for 1969 is reported as the most recent, but results for the other years were quite similar. 34 James P. Cunningham 79.3 Table 3 a. Correlation coefficients from time series analysis of the allindustry Table 3 b. Correlation coefficients from time series analysis of the wood-using industries Table 3 c. Correlation coefficients from time series analysis of the paper industry. Table 4. Correlation coefficients from cross section analysis over industrial sectors, 1969. Of particular interest in the matrices are the high correlations, encoun tered in these and in all other analyses performed so far, between capital stock and energy flow. This correspondence supports the view that energy can be substituted for capital in economic theory, particularly where com parison of unlike outfits of capital is concerned. The Cobb-Douglass function for the aggregate time series is 1) log Q = .263 + .103 log L+ .850 log K or Q = 1.301 L • 103 K • 850 for which r 2 = .977 aggregates Q L K E Lt Kt Q 1.000 L 774 1.000 K .77 5 1.000 E 981 .779 .983 1.000 Lt 0 7 2 .680 .975 .987 1.000 Kt 173 .35 3 .23 4 .12 2 .06 4 1.000 Q L K E Lt Kt Q 1.000 L 190 1.000 K 967 .212 1.000 E 895 .192 .938 1.000 Lt 867 .03 8 .906 .97 3 1.000 Kt 662 .268 .687 .412 .3 56 1.000 Q L K E Lt Kt Q 1.000 L 126 1.000 K 970 .105 1.000 E 9 2 8 .009 .9 53 1.000 Lt 87 1 .07 8 .888 .975 1.000 Kt 568 .16 4 .630 .386 .232 1.000 Q L K E Lt Kt H Q 1.000 L 880 1.000 K 950 .755 1.000 E 870 .684 .920 1.000 Lt 245 .135 .447 .63 1 1.000 Kt .48 7 .30 7 . 519 .6 82 .599 1.000 H 57 5 .4 92 .644 .628 .330 . 6 1 7 1.000 79.:) An Energetic Model Linking Forest Industry and Ecosystems 35 6 16630 —73 and the best energy function is For the combined wood-using industries, the time series Cobb-Douglass function is Now the best energy model has two explaining variables: However, the simplest energy model may still be useful for certain purposes. For the paper industry alone, the Cobb-Douglass function estimated from time series data is Again the best corresponding energy function is 2) log Q = .133 + .751 log E or Q = 1.142 E 751 for which r 2 = .9 03 1) log Q = .977 .073 log L + .880 log K Ol' Q = 2.656 L~ 073 K 880 for which r 2 = .936 3) log Q= .142 + .771 log E + .7 74 log Kt or Q = 1.153 E- 771 Kt- 774 for which r 2 = .90 5 2) log Q= .313+ .921 log E or Q = 1.368 E p 921 for which r 2 = .801 1) log Q = .181 .209 log L + .971 log K or Q = 1.198 L - - 209 K 971 for which r 2 = .942 3) log Q = .240 + .86 8 log E + .04 6 log Kt 01' Q = 1.292 E' 868 Kt -646 for which r 2 = .913 36 James P. Cunningham 79. S but we may also be interested in the simpler Turning to the 1969 cross-section analysis, the Cobb-Douglas function is and the best energy function is again an improvement over the simple The confidence limits for the coefficients of variables in all models are presented in Appendix Table 3. 4.4. Interpretation Compare the performance of the two classes of production functions first in terms of their values for r 2 , a measure of the proportion of variation in value added which has been explained by the analysis. For the time series data aggregating all industries, it is clear that the model for only one input, energy, performs as well as that employing labor and capital inputs. This is rather interesting in view of the fact that the wage bill alone, which in fact is largely derived from the labor input by simple multiplicative trans 2) log Q = .272 + -967 log E or Q = 1.312 E" 967 for which r 2 = .861 1) log Q = .750 + .375 log L + .626 log K or Q = 2.138 L- 375 K- 626 for which r 2 = .9 64 4) log Q= .260+ .918 log E .529 log Lt or Q = 1.297 E -918 Lt — 529 for which r 2 = .909 2) log Q = .346 + .672 log E or Q = 1.41 E- 672 for which r 2 = .7 56 79.3 An Energetic Model Linking Forest Industry and Ecosystems 37 formations, accounts for some 40 % of the value added during the study period: Thus there is considerable »built in» correlation between these inde pendent and dependent variables. In contrast, the costs of energy purchased have been about 16 % of value added in manufacturing, and energy prices are by no means directly related to the work input. Looking at individual sectors of industry, it is to be expected that the explanatory power of the two types of models will fall off considerably. However, for the paper indus try their performance holds up rather well, perhaps because it is so highly capital- and energy-intensive. Autocorrelation of the residuals was tested but not completely analyzed. For the intermediate level of aggregation com bining the woodworking and paper industries, the result is somewhat out of the ordinary: the degree of explanation is slightly less than for paper alone, although the differences are not significant. This can be attributed largely to the mixed fortunes of the Finnish wood working industry during the study period. The output and input use of this sector has been declining relative to the rest of the industrial system: its real growth has averaged only 4.3 % annually during this time, in contrast to 6.2 % for all industries together and 9.2 % for paper production. This has been due in part to competition for raw materials from the more efficient paper industry, and in part to the relatively slow growth of international demand for worked-wood products. Annual fluctuations have also been greater. In the context of this report, this weakness and instability suggest that prices and output in woodworking have perhaps been more determined by demand conditions in the raw material and product markets, than by inputs of factors of production. In fact, single-sector time series were analyzed for that industry, revealing that coefficients of the variables in both energetic and traditional economic models barely differed significantly from zero. Cross section analysis is a more rigorous test of the energy-output relation ship because of the much greater variability encountered in all features of industry. Some difference does appear, but still models of both classes ex plain better than 90 % of the variation. With reference to the slightly lower degree of explanation afforded by some of the energy functions, it should be noted that the energy data used are incomplete, particularly in single-sector time series: for the sake of consistency, the better information available from 1965 forward has been excluded. An interesting feature of the labor-capital time series functions is the apparently small and uncertain influence of labor on changes in produc tion in Finland during this period, evidenced by the range of estimates for the labor coefficients in the linear functions: 38 James P. Cunningham 79.3 This is not so surprising, since the two decades spanned by the data have witnessed rapid industrialization and transformation from an economy which relied heavily on primary industries, and manual labor in many activities. The accompanying rural-to-urban migration, now slowing or even reversed in most western European countries and the United States, is still gathering force in Finland. Under these circumstances, it is reasonable to expect productivity from the acquisition of capital to be high relative to that of labor. To get an idea of the returns to scale in Finnish industry, look at the sums of the input coefficients for each model. These are .953 for all industry, .807 for wood-using industries and .7 62 for the paper industry, some what less than the unitary value of the standard Cobb-Douglass function. Corresponding coefficients of the simplest energy functions are 0.751, .921 and .861, respectively. These findings are in accord with statements made by the Economic Planning Centre that the »rates of return on capital have been low» (31, p. 169) and that »demand for energy has grown slightly faster in Finland than domestic product.» International comparisons the present author is making among OECD countries are expected to help explain the relation between energy and the productivity of capital. Input coefficients, with 95 % confidence Industry Labor Capital All ,103± .809 . 850 ± .117 Wood-using —. 07 .644 .130 Paper . 209± .951 .971± .239 5. CONCLUSIONS AND PROGRAM OF FURTHER WORK The dependence of industrial activity on energy sources has been clear enough from an engineering standpoint. The results of this study, although limited in scope and exploratory in nature, support the view that it will be fruitful to incorporate energy measures as explicit variables in certain economic models. More work is needed in this area, to strengthen or refute this assertion. This author intends to continue along this line, developing appropriate theoretical formulations and testing them empirically at each step. Such models also provide framework for the more specific investiga tion, now going on, of interactions of forest-based industry with the forest and water ecosystems of Finland. The paper industry in particular is well suited to a project of this kind. It is of considerable economic importance to this country, highly energy -intensive, and its chief raw material is a biological product which has alter native uses as fuel or as structural material (including all end-product uses of wood in which the potential chemical energy stored by the sun is not released: paper, furniture, building materials, and the like). Other considera tions are that the dynamics of primary production in temperate forest ecosystems have been rather thoroughly studied and, focusing on the paper industry, the technology of production is fairly standardized and concen trated in a few large establishements. In addition, we have seen that this industry generates most of the water pollution in Finland. Special attention is directed to the proportion of the energetic content of wood which is in corporated in the final product, in relation to that which is utilized as fuel or deposited as waste. Literature cited 1. Allen, R. G. D. 19(58. Macro-economic theory: A mathematical treatment. New York. 2. Cook, Earl. 1971. The flow of energy in an industrial society. Scientific American, 224: 3, 134—147. 3. Cop e, Dav i d. 1973. Personal communication. 4. Duffield, John W. 1971. Personal communication. 5. Engel m a n n, M. D. 1966. Energetics, terrestrial field studies, and animal productivity. Advances in Ecological Research, 3, 73 —115. 6. Georgescu-Roegen, Nicholas. 1971. The entropy law and the eco nomic process. Cambridge, Massachusetts. 7. Grayson, Arnold J. 1973. Personal communication. 8. Hicks, John R. 1946. Value and Capital. Oxford. 9. Imatran Voima Osakeyhtiö. 1970. Energian tarve ja talouskasvu. (2 volumes.) 10. Kemp, W. B. 1971. The flow of energy in a hunting society. Scientific American, 224: 3, 104—115. 11. Kuusela, Kullervo. 1972. Kasvimassan tase metsä- ja puutaloudessa. Unpublished working paper, Helsinki. 12. Malaska, Pentti. 1971. Ecosystem and technoSystem: a problematic rela tion. Turun Kauppakorkeakoulun Julkaisuja, Sarja B 11-2. 13. —»— 1972. Suomen energiapolitiikan tarkastelua. Suomen Pankin energiatalou den työryhmä. 14. Meadows, Donella H., Dennis L. Meadows et al. 1972. The limits to growth: a report for the Club of Rome's project on the predicament of mankind. London. 15. Metsäekonomianosasto, Metsäntutkimuslaitos (Forest Economies Department, The Finnish Forest Research Institute). 1972. World Bank Mera Loan: Forest improvement project in Finland. Unpublished document, Helsinki. 16. Metsäntutkimuslaitos. 1971. Metsätilastollinen vuosikirja 1970. (Yearbook of Forest statistics 1970.) Suomen Virallinen Tilasto (Official Statistics of Finland) NVII A: 3. 17. M i 11, Jo h n Stuart. 1891. (Routledge edition.) Principles of political econ omy. London. 18. Niitamo, Olavi. 1958. The development of productivity in Finnish industry 1925—1952. Productivity Measurement Review, No. 15. 19. Odum, Howard T. 1971. Environment, power and society. New York. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 41 20. Organization for Economic Cooperation and Development. 1966. Energy policy problems and objectives. OECD Paris. 21. OECD. 1970. Eutrophication in large lakes and impoundments. Uppsala sym posium. OECD Paris. 22. OECD Environnent Directorate. 1972. Advanced pollution abatement technology in the pulp and paper industry. OECD Paris. 23. Palo, Matti. 1972. Impact of social, economic and technological change on forestry and wood-based industries. ECE/FAO Symposium on coordination between forestry and the wood-using industries. Helsinki. 24. Pulliainen, Kyösti and Pertti Seiskari. 1972. Ympäristömme systeemit. (Seen in draft of english translation.) Helsinki. 25. Rappa p o r t, Roy A. 1971. The flow of energy in an agricultural society. Scientific American, 224: 3, 116 —133. 26. Kobin s o n, Joa n. 1953 —1954. The production function and the theory of capital. Review of Economic Studies, 21, 112 —135. 27. Romantschuk, Hakan. 1973. The Pekilo process: protein from spent sulfite liguor. Oy Tampella Ab, Tampere, Finland. Mimeograph. 28. Sain i o, Jorma and Pentti Sorr o 1 a. 1968. Different fuels in the generation of industrial heat and power and in the generation of heat by real estates in 1965. Folia Forestalia 40. 29. S a ] o, Esko and Risto Seppälä. 1971. Fuelwood consumption on farms and in buildings, intermediate inventory, 1969/70. Folia Forestalia 120. 30. Singer, S. Fred. 1970. Human energy production as a process in the bio sphere. Scientific American, 222: 3 p. 175—190. 31. Solo w, K. M. 1955—1956. The production function and the theory of capital. Review of Economic Studies, 23. 101 —lOB. 32. Taloudellinen Suunnittelukeskus (Economic Planning Centre). 1972. Growth prospects for the Finnish economy up to 1980. Helsinki. 33. Tans 1 e y, A. G. 1935. The use and abuse of vegetational concepts and terms. Ecology, 16: 3, 284—307. 34. Tilastokeskus, Helsinki (Central Statistical Office). 1956 —1971. Suomen tilastol tollinen vuosikirja (Statistical Yearbook of Finland). 35. Tilastokeskus 1954 —1969. Teollisuustilasto (Industrial Statistics of Finland). 36. Tilastokeskus 1972. Ympäristötilastollinen vuosikirja 1972. (Yearbook of Envi ronmental Statistics of Finland 1972.) Helsinki. 37. A" ir o. P. J. 1969. Prescribed burning in forestry. Metsäntutkimuslaitoksen Julkaisuja 67.7. James P. Cunningham 79.3 42 38. The White House, Washington. 18 April 1973. A proclamation by the President of the United States of America. 39. The White House. 29 June 1973. President's statement on energy. 40. Yapp, W. B. 1972. Production, pollution, protection. London. 41. Oller, L.-E. 1973. Factors and aspects of long-term economic growth in Fin land. Senior economic advisors to ECE governments. Seminar on factors and conditions influencing long-term growth. Stockholm, 3—B December 1973. Seen in preliminary draft. 42. The energy crisis: time for action. 1973. Time, May 7, 31 —35. 43. The oil wealth. 1973. The Economist 247: 6767 p. 39—45. 7 10630—73 SELOSTE Metsäteollisuudella on perinnäisesti ollut tärkeä asema Suomen kansantaloudessa- Se yksin vastaa yhä noin puolesta maan vientituloista. Samanaikaisesti yritykset, valtiovalta ja suuri yleisö Suomessa kohtaavat eräitä ajankohtaisia ongelmia, jotka ovat tyypillisiä kaikille teknisesti kehittyneille maille: (1) Raaka-aineiden ja energian niukkuus rajoittavat metsäteollisuuden tuotoksen kasvua. (2) Eriasteisia ympäristön haittavaikutuksia syntyy jokaisessa tuotannon vaiheessa metsänuudistamisesta metsä teollisuustuotteen lopulliseen käyttöön saakka. Tämän tutkimuksen keskeisenä tarkoituksena on sekä teoreettisesti että kokemus peräisen aineiston avulla osoittaa metsäteollisuuden raaka-aineiden, voimantarpeen ja ekologisten vaikutusten keskinäiset dynaamiset riippuvuudet mitattuna energian virtoina ja varantoina. Näitä teollisuuden ja ekosysteemien välisiä riippuvuuksia voidaan seu raavassa vaiheessa hyödyntää vertaamalla vaihtoehtoisten taloudellisten toimenpiteiden edullisuutta energiassa mitatuin kustannuksin ja hyödyin. Noin kymmenen viime vuoden kuluessa ekologit ovat edistyneet huomattavasti kvantifioimalla monimutkaisia ekosysteemejä energiatutkimuksen keinoin. Toisaalta polttoaineiden välttämättömyys teollisuudelle on luonnollisesti aina tiedostettu, mutta aivan viime vuosiin saakka yleisesti uskottiin, että uusia energialähteitä voitaisiin kehittää riittävästi. Tarkastellessamme tapahtunutta kehitystä voimme todeta naut tineemme jokseenkin pitkään muihin tuotantokustannuksiin verrattuna vakaahintai sesta ja huokeasta energiasta. Puu- ja paperiteollisuudessa esiintyy eräitä omaperäisiä energiaan liittyviä piir teitä. Ensinnäkin niiden pääraaka-ainetta puuta tuottava metsä on uudistuva luonnon vara. Metsän jatkuvan uudistumiskyvyn taustatekijä on sen omintakeinen energia talous: Metsiä pidetään yhtenä tehokkaimmista nykyisin tunnetuista keinoista aurin gon energian kahlitsemiseksi, muuntamiseksi ja varastoimiseksi. Puu voidaan sitten jalostaa erilaisiksi tuotteiksi, käyttää polttoaineena tai siitä voidaan valmistaa jopa ravintoa. Suomella on ehkä ainutlaatuinen asema maailmassa siinä suhteessa, että puuta eri muodoissaan on käytetty suhteellisen paljon lämmitykseen ja voiman lähteenä. Näihin tarkoituksiin puuta käytettiin aikaisemmin pääasiassa polttopuuna. Sittem min etenkin metsäteollisuuden erilaisten jätteiden poltto on huomattavasti lisäänty nyt. Toisaalta tiedetään, että pääosa Suomen vesistöjen jätekuormituksesta on paperi teollisuuden aiheuttamaa. Tämä jätekuormitus voidaan nähdä myös ympäristöä pilaavana energiapurkauksena ja siten hukattuna voimavarana. Kuvassa 5 b (s. 21) on esitetty tällaisen »metsäsysteemin» olennaiset alkiot ja riippuvuudet. Ekologiassa ja teknologiassa käytetyt mittausmenetelmät ovat tarpeen pyrittäessä kvantifioimaan edellä kuvatun »metsäsysteemin» energiariippuvuuksia. Niiden tunte minen toisi uutta tietoa monia metsäsektorin päätäntätilanteita varten. Kokemus peräisen aineiston käyttö tässä ensimmäisessä tutkimusraportissa on ensi vaiheessa, kuvailevaa. Tällöin yksilöidään Suomen teollisuudenalojen energian lähteet ja ver 44 James P. Cunningham 79.3 rataan eri alojen energiatarvetta. Toisessa vaiheessa rakennetaan teollista toimintaa kuvaavia yksinkertaisia taloudellisia malleja käyttäen myös energiamuuttujia. Läh tien koko teollisuustuotannosta ja 26 teollisuusalasta hahmotellaan viitekehikkoa puu- ja paperiteollisuuden yksityiskohtaisempaa tutkimista varten. Jalostusarvon suhde energian nettokäyttöön oli 21 penniä kilowattituntia koh den puuteollisuudessa, mikä on hieman korkeampi kuin koko teollisuuden keskiarvo, joka oli 18 p/kWh. Tuotos/energia-suhde massa- ja paperiteollisuudessa oli 7 p/kWh, joka on yksi alhaisimpia kaikista teollisuudenaloista. Tällainen vertaileva tieto saattaa osoittautua hyödylliseksi kokonaistaloudellisessa suunnittelussa . Cobb-Douglass-tyyppisiä tuotantofunktioita kehitettiin käyttämällä perinteisten työ- ja pääomapanosmuuttujien lisäksi energiamuuttujia. Mallit testattiin Suomen teollisuustilaston antamalla aikasarja- (1954—1969) ja poikkileikkausaineistolla. Saa dut tuotantofunktiot selittivät teollisuuden tuotosta jokseenkin hyvin. Energia muuttujia käyttämällä päästiin työpanos- ja pääomapanosmuuttujia vastaaviin tuloksiin. Jatkotutkimuksissa tulisi erityisesti kiinnittää huomiota tapauksiin, joissa raha- ja energiamitoin saadut arvot poikkeavat olennaisesti toisistaan, koska näin lienee mahdollista yksilöidä puutteellisuuksia rahamittoihin perustuvassa järjestel mässä. Tämän tapaisessa tutkimuksessa tarpeellinen tietojen saanti aiheuttaa joitakin •esteitä, jotka eivät kuitenkaan vaikuta voittamattomilta. Metsien ekosysteemeissä tapahtuvan alkutuotannon dynamiikka on nykyisin jo melko hyvin tutkittu ja ymmär retty. Niin ikään metsien poistuma, hakkuumäärä ja puunkäyttö ovat Suomessa melko hyvin tilastoituja. Ympäristön pilaantumisen energiavaikutusten tunteminen muo dostaa heikoimman renkaan tässä ketjussa, mutta tiettyä edistymistä myös tämän aihepiirin tuntemisessa on viime aikoina tapahtunut. Vuodesta 1965 lähtien sisältyy Suomen teollisuustilastoon melko yksityiskohtai nen energian käytön luokittelu päätyypeittäin erikseen kullakin teollisuusalalla. Esi merkiksi puu- ja paperiteollisuudessa koko energian käyttö on tilastoitu 10—27 luok kaan. Kokonaistaloudellisen suunnittelun kannalta kiireellisimmältä tuntuu eri toimi alojen välisten energiansiirtojen rekisteröinti ja laatiminen mahdollisesti panos-tuotos taulujen muotoon. Tällainen järjestely helpottaisi riippuvuuksien kuvailua ja mahdol listaisi teollisuuden välillisten ja välittömien energiakustannusten huomioonottamisen. RESUME L'industrie finlandaise ä base de hois soutient vine large partie de l'economie nationale et est la source majeure des revenus d'exportation. En meme temps les entreprises, le gouvernement et le publique confrontent des problemes qui sont com muns aux pays developpes au point de vue de technologie: l'insuffisance en matieres premieres et sources d'energie limite la croissance: 2) l'endommagement du milieu ä chaque etape, depuis la silviculture jusqu' ä la vente du produit final. Le premier but de cette etude est de demontrer l'interdependance dynamique de la matiere premiere, les sources d'energie, et les effets ecologiques en termes de flux et depots d'energie. Les relations entre industrie et ecosystemes peuvent etre utilisees alors afin de comparer le cout d'energie et les benefices provenant d'activites economi ques alternatives. L'ecologiste, tentant de mesurer les systemes complexes biologiques a l'aide d'etudes d'energie, a fait des progres considerables dans cette direction pendant les dix dernieres annees. Le besoin de combustibles pour l'industrie a ete reconnu egalement, mais il a ete assume jusqu' ä recemment que des nouveaux stocks d'energie pouvaient etre developpes comme desire. II est vrai que nous avons joui d'une longue periode de cout stable d'energie, cout bas en comparaison avec d'autres ressources. Mais il est peu produetif d'analyser cette complaisance en retrospect. Les industries ä base de bois montrent quelques caracteristiques peculieres d'ener gie. La matiere premiere est renouvellee continuellement. En fait, la foret est le moyen le plus efficace pour l'aecumulation, la transformation, et l'emmagasinage de l'energie solaire. Le bois peut etre employe comme combustible ou bien transforme en nourriture. La Finlande occupe une place unique au monde par son degre de dependance du bois jadis sous forme solide et plus recemment par une technologie sophistiquee de recupera tion de dechets- pour le chauffage et comme generateur d'energie. Notre milieu est snjet d'une tension energetique considerable, particulierement sous forme de pollution d'eau; cette tension peut etre consideree comme ressource gaspillee. La figure 5 represente les chaines essentielles du systeme. Les techniques empiriques de l'ecologiste et de l'ingenieur fournissent les donnees necessaires aux decisions economiques employees dans l'etude de ces chaines. Le travail empirique presents iciest en partie deseriptif; les sources d'energie de l'industrie finlandaise y sont identifiees et une comparaison est etablie entre les demandes en energie dans les differents secteurs. II en a ete conclu que le rapport entre production et usage net d'energie est ä peu pres. .21 marques finlandaises par kilowattheure pour l'industrie boisiere mechanique. Ceci est un peu plus haut que la moyenne de .18 marques par kilowattheure pour l'ensemble des industries, tandis que ce rapport est un des plus bas dans les industries ä base de bois et de papier, soit. 07. Des comparai sons pareilles peuvent prouver utiles pour les decisions economiques au niveau national. Afin d'etablir un cadre pour une etude plus detaillee des industries forestieres, quelques modeles economiques simples d'activite industrielle ont ete considere et ont ete for mnle en termes energetiques. Les fonctions de production de la forme Cobb-Douglas 46 James P. Cunningham 79.3 ont ete base sur main-d'oeuvre et capital ainsi que sur variables d'energie provenant de series de temps et de donnees d'une section transversale des industries finlandaises. Les resultats des deux categories de modeles sont generalement en accord et ils expli quent bien les variations en production. Les differences entre les evaluations mone taires et energetiques doivent etre examinees soigneusement puisqu'elles peuvent servir ä identifier des aires incompletes dans le systeme monetaire. Un des obstacles est la necessite de donnöes, mais il est possible de le surmonter. La dynamique de la production primaire de l'ecosysteme forestier en zone temperale est bien connue; les statistiques concernant I'enlevement et I'usage du bois sont com pletes pour la Finlande. Les effets energetiques de la pollution n'ont pas ete etudie en profondeur mais des progres sont faits dans cette direction. Depuis 1965 la statis tique industrielle finlandaise a tenu une comptabilite detaillee de I'usage direct de diverses formes d'energie secteur industriel. Par exemple toutes les statistiques d'energie ont ete registre pour au moins 10, et en quelques cas 27, subsecteurs de I'industrie boisiere. Au pian national il existe vis-a-vis de la planification eco nomique un besoin urgent pour des donnees comprehensibles faisant reference aux transfers d'energie entre secteurs et organisees eventuellement sous forme de tableaux ressources-production. Ceci clarifiera les interdependances et permettra d'ajouter les couts directs et indirects d'energie des industries. KPATKOE H3JIOJKEHME 'l>iiiicha>i aepcßOOöpaöaTbißaromaH n nejunoaoaiio-oyMajKnair npoMbimjieHHocTb COCTaBJIHIOT BaiKHVH) 'iaCTI. HaUHOHajIbHOH 3KOHOMHKH II HBJIHIOTCH OCHOBHbIMH lICTOIHHKaMH 3KCnOpTHbIX HOXOHOB. B TO »ie BpeMH Horo nepnoaa 3HeprentKKaMH npOH3BO3,CTBa. OrpacjiH iipoMbiiHJieniiocTH , Hcriojibsyroiune b Ka liecTße cbipbH npeßecHiiy, HMeioT CBoeoöpasHyio SHepreTHqecnyio xapaKTepncraKy. ripeHtae Bcero, apeßecHHa Henpepbißiro bo3o6hobjihctch; jieca H3 Bcex H3BecTHbix cnocoöoß (JmKTHHecKH iipeacTaß.TiiioT co6ok> Hanoo.Tce :)<[><[>eKTnisHoe cpeacTßO jijih yjiaßjiiißaiiHn, npeoSpa soßaiiHH h naKonjieHHH cojniemioft SHeprnn. JlpeßecHHy b aajibHeftuieM mo>kho iiepepaöaTbißaTb b Hsae.'ma, ncnoJib3oßaTb b Ka'iecTße ropio'iero hjih H3roTOBJiHTb niimeßbie nponyKTbi. Ohhjihhjihh b stom OTHorueHHH 3aHHMaeT b Mnpe hckjhoto- TeJibHoe nonoweHHe, nowajiyii, Sojiee *ieM Kanan jihSo npyran CTpaHa OHa nojn>3o - apeBecHHOH hjih OTOiiJieHHH h BbipaöoTKH 3HeprHH, b cbipoM Bii;ie, a iiocjiejinee BpeMH b xone TexHHHecKH jjocTaTOHHO coßepiueHHwx nponeccoß yTHJIH3aHHH OTXOHOB OCHOBHOTO npOH3BOJJCTBa. 3HaqHTejlbHaH 3HepreTHHeCKaH HanpHJKeHHocTb, HMeiomaH MecTo b Haiueil 3KOCHCTeMe, ocoöeHiio b (JopMe 3ar- PH3HCIIHH BOHHbix SacceHHOß, MOHteT, cjieflOßaTejibHO, paccMaTpntiaTbca Kan 6ecno- Jie3nan pacTpaTa 3HepieTnLieci;nx pecypcoß. Phcvhoi; 5 6 (cTp. 21) nona3bißaeT OCHOBHHe 3BeHbH CBH3eft B JiaHHOH CHCTeMe. MeTOHHKa H3y iieniih sthx cßH3eii ncno.ibayeT sMinipii'iccHyio TexraiKy 3ko.ho rrmecKHX h HHHteHepHbix HccjieaoßariHH h HMeeT uejlbio gaTb aanHbie hjih npHHH- TiiH anoiiOMHHecKHx peiueHHH. SMiiHpiPiecKaH pa6oTa, npeacTaßJieHHan b btom 48 James P. Cunningham 79. s nepBOM HOKJiaae , hocht 'lacTirmo onneaTejibHbifi xapaKTep , b new npocTo yKa3aHW hctohhhkh SHeprmi 3JIH npoMbimjieHHOCTH Ohhjihhhhh , npoßeaeno cpaßHeHiie 3HepreTHHecKnx noTpeÖHOCTeft pa3JiHHHbix ceKTopoß npoMbimjieHHOCTH. EbiJio ycTaHaßJieHo , hto cooTHoiueHHe Me?K,ny npiipoeroM ctohmocth h noTpeSjieHiieM 3HeprHH cocTaßjmeT npnMepHO 21 (})hhck. Mapon Ha KiuiOßaTTiac b jiepeßO oopa6a'[i>[iiaioineii ripoMbiiiiJieHiiocTii, >ito HecKOJibHO Bbiiue new b cpeaHCM hjih Bceti npoMHniJieHHOCTH lB (jMH/KHJiOßarraac; b to >Ke BpeMH cooTHoiueHHe Meway npoH3BoacTBOM roTOBOH npoayKUHH h noTpeSoieHHeM SHeprHH b LtejiJiK)- JIO3HO-6yMa»tHOM npOH3BOHCTBe HBJIHeTCH CaMbIM HH3KHM H paßno 0.7. Tanan cpaßHHTejibHaa HH(J:opMamifi movkct OKa3aTbCH nojie3Hoft hjih aKonoMimecKoro nJiaHnpoBaHHH b Macmraoc uejioft crpanij . C nejibio no.;iyie,HHh ochobm aan Sojiee aeTajibHoro nayieiiHJi jiecHoft npoMbimjieHHOCTH 6bi.nn B3HTbi HecKo.ibi;o npocTbix Moaejiett npoMbimjieHHoii jjeHTejibHOCTH h nepecTpoeHbi Tan, itoSh nojiy 'iaTi) pe3yjibTaTbi b 3HepreTHHecKHX iioi;a;iaTe.i;ix . IlpoßepeHbi ii poh3bo;(ct behh bi e (JjyHKHHH Kooo-jlyr.iraca KaK Ha MaTepiia.Tie noxpeÖJieHHH pafiCHJibi h Kamrrajia, TaK h nepeMeHHbix c, Hcnojib3oßaHneM gaHHbix hjih Bceti (Jhhckoh npoMbimjieHHOCTH c 1954 no 1969 rr. OKOHnaTejibHbie aaHHbie, ot 3Thx jjßyx Tunoß Monejiett, oKa3ajmcb b oöiyeM cxouhbimh, ho3bojihbuihmh aocTa tohho xopomo o6i,HCH>nb pa3JiHHHH b HOHCiHbix pe3yjibTaTax . Etpn paöoTe no aaHHOMy MeToay cjiynan pacxojKHeiiHii b oueHKe no neHe>KHbiM h 3Hepre™~ qecKHM pe3yjibTaTaM HeoöxojmMO TmaTejibHO aHajiH3npoßaTb, TaK KaK ohii nacTO MoryT cjiV/KiiTh hjih o6napy>KeHHH HenojiHOCTii aeHOKHon CHCTeMbi oueHKH. TpeooßamiH , npeHT>HßJiHeMbie k hcxohhmm aaHHLiM, npencTaßJiHiOT onpejiejieH - Hbie TpyHHOCTH, ho ohh He HBJIHIOTCH HenpeOHOJIIIMbIMH . fIHHaMHKa nepßimHoro npoii3Bo;iCTßa b Jiecax yMepeHHOii 30hm msyiena cpaßHiiTejibHO xopomo ii CTaTiic- AaHHbie 06 OTnycKe Jieca h ncnojib3oßaHHH JiecHHX pecypcoß b iih jihhjjhh nocTaTOMHO nojiHbie. .SnepreTinecKoe bjihhhhc 3arpH3HeHHH cpeabi He ÖbIJIO OCHOBäTeJIbHO HOKyMeHTHpOBaHO , HO B HaCTOHHjee BpeMH B 3TOM OTHOnieHHII MMeeTCH onpeaejieHnbiH nporpecc. C 1965 roaa (jmHcnan npoMbimjieHHaH cTaTnc- THKa BeaeT HOCTaTOHHO neTajibHbiH yneT npHMoro noTpeöJieHHH SHepniH b pa3JiHq- Hbix no OTgejibHbiM ceKTopaM npoMbimjieHHOCTH. TaK, HanpiiMep, b a,epeßo oSpaöaTbißaiomeft npoMbimjieHHOCTH CTariiCTii'iecKiiii yicT noTpeöJieHHH sn cp mu ocymecTßJiflioT no 10 h, b HeKOTopbix cjiynanx, no 27 cyöceKTopaM. JXnn reHe pajibHoro 3KOHOMnqecKoro nJiaHnpoBaHHH b HauHonajibHOM MacurraSe KpaöHe HeoöxoßHM no.:iiibifi yieT nepeaaiH snepriiii ot ohhoro ceKTopa K apyroMy, no- BHjtHMOMy, b BH«e TaÖJiHH, noicasi.ißaiomiix nocTynjieHHe h nepe;ia>ty siieprim . 3to bmhbhjio 6bi B3aHMOCBH3H h no3BOJinjio 6bi yiiiTMßaTii npHMbie h HenpHMbie 3HepreTHiecKne 3aTpaTbi b npoMbimjieHHOCTH. 79.3 An Energetic Model Linking Forest Industry and Ecosystems 49 Appendix Table 1 a. Whole industry data indices. Appendix Table 1 b. Wood-using industries data indices. Q L K E Lt Kt 1954 100000 100000 100000 100000 100000 100000 1955 114766 105599 110760 098761 093524 109052 1956 123286 103670 112911 107310 103511 106218 1957 127577 102207 128701 108179 105843 111649 1958 123632 096328 130492 114207 118560 111609 1959 135082 100326 138887 114208 124867 107236 1960 148653 109142 154277 148530 136089 099326 1961 161166 113814 167531 149545 131394 117504 1962 169145 115168 178820 156139 135575 119391 1963 177770 112857 183527 175453 155465 114340 1964 181742 114381 201889 195919 171287 107974 1965 185939 115487 204976 206254 178595 119557 1966 199642 114965 229551 223967 194813 115391 1967 214292 111681 247155 231916 207659 113586 1968 237028 109665 249251 250441 228370 108907 1969 261208 114767 266535 293684 255895 098722 Q L K E Lt Kt 1954 100000 100000 100000 100000 100000 100000 1956 121586 103144 109711 094214 091342 114560 1956 120510 091183 113541 094535 103676 118099 1957 143713 090843 126703 099929 110003 119111 1958 147088 093190 130205 102235 109706 122748 1959 150488 096933 138582 108137 111559 122198 1960 177680 110536 157595 113196 102406 130918 1961 190173 112543 179071 131231 116606 145929 1962 187463 108421 197350 130216 120103 152454 1963 203721 107433 195169 133831 124571 163285 1964 210743 107764 213215 162016 150344 143588 1965 212389 106448 233061 222331 208863 112927 1966 217364 100256 250460 172566 172125 157597 1967 229638 093861 262350 179866 191631 152916 1968 289849 095080 265788 179285 188563 153325 1969 320711 099555 288285 238838 239905 126771 50 James P. Cunningham 79.3 Appendix Table 1 c. Paper industry data indices. Appendix Table 2. 1969 cross section data. 0 L к E Lt Kt 1954 100000 100000 100000 100000 100000 100000 1955 137000 107428 111789 111107 103426 098722 1956 147649 106719 118561 119012 111522 096694 1957 172176 109215 133758 126811 116114 095837 1958 175265 106648 137717 127910 119938 103174 1959 176516 111831 147613 135880 121505 103013 1960 206262 122653 171442 138258 112725 114869 1961 228572 132409 198492 162589 122797 131619 1962 233104 132286 221737 164592 124421 135438 1963 256340 131304 216999 171723 130787 143599 1964 266575 133014 237836 206077 154931 127712 1965 269983 132765 263059 295792 222798 096054 1966 280798 129492 285365 227481 175673 164652 1967 297058 123129 298154 239110 194196 130367 1968 375439 123580 302888 240385 194522 129096 1969 409461 126395 328323 323847 256224 105989 Q L K E Lt Kt H 12 293880 5720000 345569 303327 11429050 30890 00000 14 18177 898000 14305 49073 11768106 14032 00000 15 30016 1742000 96758 92821 11487748 33108 00000 16 4320 555000 7403 7188 2786047 36519 00000 •20 . .. 1269335 79774000 1889270 3630693 9808707 06740 26856 21 . . . 193869 8897000 352515 529212 12820058 03842 16115 22 57605 2145000 108286 52013 5227437 07548 11820 23 ... 479933 48823000 1093666 1383406 5849744 07580 51340 24 ... 451741 54937000 268019 268953 1055090 07919 07170 26 . .. 732404 62135000 1050291 3548532 12308043 08143 17064 26 . .. 213976 24158000 215298 390591 3484620 11268 04734 27 ... 2070758 70938000 6253474 27771410 84373113 07826 39142 28 ... 606318 36354000 521916 256643 1521479 11512 00000 29 38803 9649000 48983 113012 2524280 11609 00877 30 ... 124134 8867000 230216 273437 6646500 13252 17186 31 ... 684252 24082000 1555164 3200466 33116753 06564 7930(1 32 ... 212135 2344000 591018 5041917 463411489 01609 26444 33 447482 29392000 912661 5403214 39618815 03051 00502 34 . .. 467554 19851000 1285905 2451050 22610031 09906 31335 35 469240 39662000 775180 8.37064 4548519 12561 02072 36 942203 67796000 1288458 1241981 3948186 15946 01141 37 ... 412709 27578000 532452 425074 3321929 13536 14549 38 ... 781199 64855000 833477 1247621 4145884 09293 05094 -39 ... 232605 17202000 228454 287207 3598183 17409 02462 51 ... 1761623 24037000 4389709 13934121 124936080 02004 223206 -52 93584 1506000 433070 147718 21132761 19862 13998 79.:! An Energetic Model Linking Forest Industry and Ecosystems 51 Appendix Table 3. Ranges of coefficient values for independent variables in all models reported, with 95 % confidence. Data set Time series Model L К Variables E Lt Kt All industry . . 1 ,103±.609 2 ,850±.117 .751±.079 Wood-using industries . . 1 —.073±.644 2 3 ,880±.130 .921 ±.245 .7 71 ±.194 .774 ±.411 Paper industry . . 1 —,209±.951 2 3 .971 ±.239 .967 ±.207 .868 ±.184 .646 ±.463 Cross section . . 1 .375±.120 2 4 .026 ±.11 1 .672 ±.156 .918 ±.125 —.529±.17 0 E PI P HYTOLO G Y OF MELAMPSORA RUSTS OF SCOTS PINE (PINUS SYLVESTRIS L.) AND ASPEN {PO PULU S TREMULA L.) TIMO KURKELA MÄNNYN VERSORUOSTEEN JA HAAVANRUOSTEEN EPIFYTOLOGIA HELSINKI 1973 ISBN 951 -40-0082- X Helsinki 1973. Valtion painatuskeskus PREFACE Numerous persons helped me during the various stages of this research. The work was initiated in the Finnish Forest Research Institute with the encouragement of Prof. Sakari Saarni joki and Prof. Risto Sarvas. During the beginning of the work, I received much beneficial advice from Prof. Paavo Juutinen and Mr. Ukko Rummu kainen. I have had important discussions concerning the studies with Dr. Allan Klingström of Uppsala University, Sweden, Dr. Veikko Hintikka, Mr. Lalli Laine, and many other col leagues. The encouraging attitudes of these persons, and especially Forest Officers, Mr. Viljo Mattila and Mr. Lauri Rantala, who are working in practical forestry, were decidedly significant in the conduct of the studies. Mr. Erkki Kaita-aho, Mr. Simo Leinonen, Mrs. Inkeri Erjala, Mrs. Toini Ojala, Mr. Matti Laurila, Mr. Larry Huldén and several other persons assisted me in the field and laboratory work. The manuscript was read and beneficial criticism given by Dr. Pe i t s a Mikola, Prof, of Forest Biology, and Dr. Eeva Tapio, Prof, of Plant Pathology, both from the University of Helsinki, and Prof. Paavo Juutinen. Dr. Kim von Weisse n berg translated the manu script, and his wife Joa n n von Weissenberg revised the English text. These studies have been included in the research program of the Finnish Forest Research Institute. With a fellowship sponsored by the W. K. Kellogg Foundation (Battle Creek, Mich. U.S.A.) and some financial support from the Society of Forestry in Finland I was able to become acquainted with current research in the corresponding field in the United States and Canada. I wish to express my sincere thanks to the persons and institutions mentioned above and to all others who have assisted during the course of this study. Helsinki, October 1973 Timo Kurkela CONTENTS Page Introduction 5 Materials and methods 7 Description of experimental plots 7 Measuring of weather factors 8 Measurement of host tree development 9 Inoculation of pine shoots with basidiospores 10 Trapping of spores and handling of material 11 Investigations on the aecial and uredial states of Melampsora 13 Results 15 Dispersal of basidiospores 15 Dispersal of aeciospores and uredospores 26 Twisting rust oil pino 33 Seasonal variation of rust incidence 33 Effect of wind on the positions of aecia on pine shoots 36 Growth stage and rust resistance of pine 37 Correlation between rust incidence, shoot length, and height of pines 38 Interaction of the development of pine and rust 39 Incidence of rust on aspen leaves 41 Discussion 45 Dispersal of basidiospores and infection of pine 45 Dispersal of aeciospores and uredospores 47 Factors affecting diurnal periodicity of spore dispersal 48 Limitations in identifying the spores of Melampsora species 49 Literature oil the morphology of spores 49 Measurements of spores 51 Characteristics which determine rust incidence in pine stands 53 Interaction of pine and rust 53 Rust on aspen leaves 54 Possibilities for control of pine twisting rust 55 Conclusions 68 Summary 61 References 62 Männyn versoruosteen ja haavanruosteen epifytologia 68 INTRODUCTION The pine twisting rust caused by the fungus Melampsora pinitorqua (Braun) Rostr. is economically one of the most important diseases in pine sapling stands in Finland (Kangas 1938, Kujala 1950). In addition to Europe, at least Asia Minor and the western part of Siberia are included in its range (L on g o et ai. 1970). The main host is Scots pine (Pinus sylvestris L.), but the fungus also infects many other pines of the Diploxylon group. In order to study the disease in depth, an international working group has been established within lUFRO. Melampsora larici-tremulae Kleb. causes the needle rust of larch. M. pinitorqua and M. larici-tremulae can be distinguished from each other only because they develop the aecial states on different hosts, the former on pine shoots, the latter on larch needles. The uredia and telia of both rusts develop on the leaves of aspen. The needle rust of larch is not known to cause any damage of economic importance for forestry. After the description of the symptoms of the disease (de Bar y 1863) and the life cycle of the pathogen (R ost r u p 1884), considerable time passed before important publications on the biology of pine twisting rust were published. From the standpoint of epiphytology, the most important of these studies were: Schafranskaj a (1940), Troschanin (1952), R e g 1 e r (1957), K 1 i n g st r ö m (1963) and Long o et ai. (1970). These studies have dealt with i.a. infection of pine, the distance to the source of inoculum, germination of teliospores, and the dependence on climatic con ditions for infection of pine. Although the main features of the cycle of the rust are known, there are no other practical methods of control except eradication of aspen from pine sapling stands. This already was recommended by Hartig (1885). In order to find new control methods, all possible gaps in our knowledge must be eliminated. Detailed studies of i.a. spore dispersal, process of infection, and the rate of development of the rust on pine and aspen have not been made. The occurrence of the rust in the uredial and telial states especially has received little previous attention. Pine twisting rust had occurred to some extent on various locations in Finland during the early 1960'5. In 1964 severe damage was caused almost Timo Kurkela 6 79. i everywhere in the country but especially in the southwestern and western parts, where, subsequently, the Regional Board of Forestry asked for initia tion of this study. This publication reports on the dispersal of the different spore types of M. pinitorqua and the subsequent development of rust on the host plants, pine and aspen, in the field conditions. Previously published results by the author (Kurkela 1973 a) on the release and germination of basidiospores are discussed in the present report in relation to spore dispersal in nature. Data on M. larici-tremulae are also included. This is due partly to the fact that observations on M. pinitorqua could not be made every year because of the scarcity of the rust, and partly due to the fact that both rusts are almost identical ecologically; therefore the results could be generalized for both species. MATERIALS AND METHODS Description of experimental plots The development of pine twisting rust was followed on locations where the disease previously had caused considerable damage. The locations of the experimental plots of this study are shown in Fig. 1. The most important part of the study was made in Jauli, Ikaalinen township, (N 61°24', E 23°26') the Location 1, where observations were made during 1965—1968. The study area was about 160—180 m above sea level. It had been clear-cut and planted with pine. The sapling stands had been beaten up several times Figure 1. Location of the experiment areas. Ikaalinen, Jauli (N 61°24', E 23°26') = Loc. 1. Laihia, Jakkula (N 62°57', E 22°06') = Loc. 2. Tuusula, Ruotsinkylä (N 60°38', E 25°09') = Loc. 3 and 4. 8 Timo Kurkela 79.4 due to the fail places caused by combined effect of rust and hardwood suckers. At the study site there were 0.5 —1 m high pine saplings mixed with some aspen suckers. In 1966 observations were also made in Jakkula, Laihia township, (N 62°57', E 22°06') Loc. 2. This area, in a spruce stand, was a North-South clear-cut strip ca. 70 m wide, planted with pine. The pine sapling stand was about I—2 m high and growing vigorously. The stand was rather densely mixed with aspen suckers. In 1970 and 1971 the dispersal of Melampsora spores was studied in the Ruotsinkylä Experiment Forest of the Finnish Forest Research Institute in Tuusula township (N 60°38', E 25°09'), Loc. 3. This study area was an opening of 20 m diameter, filled with low (about 0.5 m) aspen suckers, located in a mixed stand of 4—6 m high pine and larch. In the spring of 1973 the basidiospore dispersal of aspen rust was inves tigated in the aspen clone bank of the Ruotsinkylä Experiment Forest (Loc. 4). The height of the tallest trees was 6—B m. When the trees were still without leaves in the spring, insolation, wind, and precipitation could freely affect the fallen leaves on the ground. During the previous summer, the ground vegetation under the trees had been eliminated by using a rototiller. Measuring of weather factors The relationship between the pine twisting rust, the aspen rust, and various weather factors were studied by following the dispersal of the patho gen spores, the development of the hosts, and occurrence of the rust on its hosts during various stages of the growing season, and by registering weather factors. Temperature and humidity. The air temperature was meas ured 2 m above the ground in a standard weather chamber by means of a thermograph or thermohygrograph. The instrument readings were corrected according to a calibrated precision thermometer in the same weather cham ber. The temperature was recorded to the nearest o.i°C. Calculations of daily mean temperatures were based on graph readings taken at every odd numbered hour. The relative humidity of the air was obtained during June—September from a thermohygrograph (hair hygrometer) placed in the weather chamber. The instrument was calibrated prior to and after use in order to detect any measurement errors. For the present investigation the measurement of high relative humidity was the most important. According to Ahti (1972), it is obvious that when the relative humidity approaches 100 %, the hair hygro meter tends to record too low values, the error being on the average larger in summer than in winter. Epiphytology of Melampsora Rusts of Scots Pine and Aspen 79.-4 9 2 16568—73 Precipitation and dew. The amount of precipitation was measured by a fluviograph with a clock making a complete revolution in one week. In 1971 and 1973, however, the fluviograph used had a clock making a complete revolution in 24 hours. The amount of water passing through the fluviograph was checked with a graduated cylinder. The pre cision of measurement was to the nearest O.i mm. In 1971 and 1973 a dew scale was used. The amount of condensed water and the duration of dew were measured. The dew scale also recorded minor precipitation when the amount of water was not sufficient to be recorded by the fluviograph. The precision of the dew scale was to the nearest O.i g. The dew scale was also used to measure the total length of the wetness period caused by both precipitation and dew. The cup of the scale was adjusted in such a manner that the water that rained into it could flow out trough the cup bottom. Thus, the recorder always deviated from zero as long as the surface of the cup was wet. With the dew scale it was not always possible to distinguish dew from rain, but this was not necessary. It was only important to measure the time during which free water, precipitated or condensed, occurred on the foliage or on vegetation in general. The dew scale was calibrated once a week with weights of 1 and 5 grammes. Wind. Wind velocity recordings from the climatological station in Kuru, Länsi-Aure, of the Meteorological Institute were used for the studies made in Loc. 1, during 1966—1968. The climatological station was located 7 km from the experimental area. The recordings were made three times a day, at 08.00, 14.00, and 20.00. The daily means of these recordings were used in the present study. This is, as such, a very crude estimate of wind velocity, and does not allow a very detailed analysis of the studies of spore flight. For the 1970 studies the data on wind velocity from the Helsinki Airport (Vantaa township) climatological station of the Meteorological Institute were used. The airport is located 5 km from the study locations Nr. 3 and 4. The recordings at the airport were made at half-hour intervals. In 1971 and 1973 the wind velocity was measured at the experimental area in Ruotsinkylä (Loc. 4). The sensor was a Lambrecht Nr. 1467G attached to the recorder, Lambrecht Nr. 1487 a. The sensitivity of the sensor was 0.6 m/sec. This device was especially useful for measuring the velocity of wind gusts. The maximum velocity for each 10 minute interval was read from the recorder's paper strip. These values were used for calculation of daily and hourly mean velocities. Measurement of host tree development Growth of shoots and needles in pine and larch. The height growth of the pine shoots was measured in order to determine Timo Kurkela 79.4 10 at what phase of growth infection by the pine twisting rust occurs in nature. Growth was measured in Loc. 1 in 1966—1968 and in Loc. 2 in 1966. In the first measurements a total of 50 saplings were included. From each sapling the growth of the terminal leader and two branches formed during the pre vious year was measured. In 1967 30 saplings were measured. In 1968 the measurements were continued in the same place as previously; but due to the serious attacks by the rust in the previous summer, only 10 saplings could be included. The reference point for the measurements was marked on each sapling with an insect needle inserted immediately below the base of the terminal bud. The measurements were made daily at noon. The work was begun in mid-May when the terminal bud had started to elongate. The measurements were made with a sliding caliper. Precision of measurement was to the near est O.i mm. One person made all measurements in Loc. 1, and another made those in Loc. 2. In connection with shoot measurement, the needle length was also mea sured. From the growing terminal leaders of pine saplings the lengths of the five uppermost and five lowermost needles were measured in 1967. In 1968 the length of 10 marked needles in each of five trees was measured. The length of larch needles in short shoots was also measured during their devel opment. Measurements were made each day, beginning on the day when the tips of the needles emerged from the fascicle, and ceased when no growth could be detected. Growth of aspen shoots and leaves. Measurement of the short shoots of aspen commenced before the buds began to expand. The reference point was taken to be the scar of the previous year's leaf at the base of the bud, and the measurements were made from this reference point to the tip of the bud using sliding calipers. During the opening of the bud, measurements had to be discontinued until the tip of the expanding shoot clearly could be detected. At this time the growth measurements of the uppermost leaf commenced. The leaf was measured from its base to the tip. Measurements were continued until no growth could be detected. Some 4—5 groups of suckers were selected for the measurements. From each group four buds were marked for the measurements. Inoculation of pine shoots with basidiospores For these experiments 2 year-old nursery-grown transplants were used. The transplants had been lifted from the nursery in the spring and placed in cold storage. The growth of the transplants was slowed down in storage until they were used. The transplants were planted in pots in a greenhouse. 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 11 The temperature in the greenhouse varied from 14 to 22° C. The relative humidity was kept at 60—95 % with an air humidifier. Of the potted transplants, the most vigorous ones were selected for the experiment and arranged into groups of ten transplants each. The order of inoculation of the groups was randomized. Since temperature has been found to be a very important factor controlling the annual growth of trees (cf. Sarvas 1965, 1972, Hari et ai. 1970), the inoculation interval for the transplants was taken to be 50 degree hours. Calculation of the number of degree hours was commenced when the transplants were potted and transferred to the greenhouse. The number of degree hours was calculated from the mean of the temperature minus five degrees at each odd-numbered hour of the day (cf. Sarvas 1965). The method developed by Moriondo (1961) was used for inoculation. The pine shoots as well as the inner side of a test tube of 25 mm diameter was moistened with a spray of water. The growing shoot was inserted into the test tube deep enough that pieces of aspen leaves, bearing sporulating telia fastened to the inner side of the tube, came level with the tip of the shoot. Before application, the aspen leaves had been incubated at 13 °C for 24 hours. It was extremely difficult to standardize the amount of inoculum, i.e. the number of basidiospres formed by the telia, since the number cf telia and their ability to germinate on the aspen leaves varied considerably, which facts have been reported also earlier (Kling ström 1972, Kurkela 1973 a). As a source of inoculum three pieces Ix 3 cm, of aspen leaves were placed inside the test tube. The inoculum was made at 15 °C over a period of 16 hours. Subsequently, the transplants were transferred back to the greenhouse. The experiments were made with two lots of transplants planted at two different times. With the first lot, eight groups of inoculations M ere made; with the second, only three were made. The smaller number of groups in the second lot was due to the fact that these transplants had been kept in cold storage longer and were, there fore, in such poor condition that a larger proportion of them had to be discarded. In both lots, one group of ten transplants was left as an uninocu lated control. The height growth of these transplants was measured each day in order to be able to determine at which phase of growth the inocula tion had been made. When the transplants were potted, they had already completed about half of their final height growth. Trapping of spores and handling of material In order to monitor spore dispersal, two instruments were used: 1) a pol len sampler developed by Sarvas and Wilska (Sarvas 1952, 1962) and 2) a modified Hirst spore trap (Hirst 1952) manufactured by Burkard Manufacturing Company. Timo Kurkela 19a 12 The results obtained by the pollen sampler of Sarvas—YVilska indicated the number of spores trapped per unit of time on a tape surface. The trapping surface was cellophane tape covered with vaseline and wrapped around the clock cylinder of a thermograph. The periphery of the cylinder moved 2 mm/hour. The device was equipped with ball bearings and a wing in such a manner that the opening of the cover was always toward the wind. The opening was conical, tapering off toward the inside. At the point nearest the trapping surface, the opening was 2 mm wide. The amount of air moving through the device was dependent on wind velocity. For each period of time the number of spores was counted on 23 microscopic fields corresponding to a total of 4.5 sq.mni. The vaseline-covered ribbons were examined intact directly under a microscope using phase contrast. The results obtained by the Hirst spore trap indicate the number of spores per unit of air volume passing through the instrument. Using an adjustable air pump the suction was standardized to 10 litres/hour. Due to variation in temperature and air humidity, the suction of the pump varied. Therefore, the pump had to be adjusted at least once in two days. The instrument had ball bearings so that it turned toward the wind. A tape wrapped around the clock cylinder was covered with vaseline and moved 2 mm/hour. The tape was changed every 6 days. For microscopic examina tion, the tape was cut into sections corresponding to each day. Each section was mounted in polyvinyl alcohol. The mounting medium used was: 35 g polyvinyl alcohol grade 40—20, 100 ml distilled water, 50 ml glycerol or 40 ml lactic acid, and 2 g phenol. Slide preparation was based on the method presented by Downs (1943). The microscopic examination was made with a X 300 magnification. The numbers of basidiospores, aeciospores and uredospores of Melampsora trapped on the tapes were counted. Different species of Melampsora were not identified since it is completely impossible for basidiospores and also extremely uncertain when single aecio- or uredo spores are examined (cf. p. 49). The observations on spore dispersal commenced in Loc. 1 at the beginning of June when the growth of the pine shoots had just started and the shoot was still covered by the bud scales. In Loc. 3 and 4, the observations com menced at the beginning of May. The dispersal of spores was related to the climate and the variation in weather factors at the time of spore trapping and to the occurrence of uredia on the aspen leaves. By using multiple regression analysis, the relationship between some weather factors and the daily numbers of uredospores was investigated. The mathematical data processing was limited to uredospores since their dis persal occurs over a much longer time than that of aeciospores and basidio spores. The following variables were used: Epiphytology of Melampsora Rusts of Scots Pine and Aspen 79.i 13 x 1 = number of days since the first uredia were observed in the field. x 2 = dependent variable, daily mean number of uredospores in the air, x 3 = number of uredia per day on a unit area of aspen leaves calculated by interpolation of the number of uredia per week, xi = average daily temperature, x . = average daily temperature for the coldest period of the day (21.00 —OB.OO hours) calculated as the average of six temperature read ings taken on odd-numbered hours, a* 6 = average daily temperature for the warmest period of the day (09.00 —20.00 hours) calculated as above, x 7 = average daily wind velocity, - x 3 /log 10 x 1; Xq x 3 jx 1« x lO = a: 3 /(xx) 2 . The calculations were made according to the stepwise regression analysis by Väliaho (1 969). By means of the first and third variable and variables B—lo formed from the former variables, an attempt was made to remove from the model the effect of the changing number of spores due to the in crease in uredia. In addition to the daily mean temperature, the average temperatures of the coldest and warmest periods of the day were also included as variables since it is possible that cold nights may in some way affect the development of the fungus, and since most of the spores are released during the warmest period of the day (cf. p. 28). Wind velocity was included espe cially because the general effect of wind was of interest and since the number of spores trapped in the two types of traps (Sarvas- Wilska and Hirst) may be dependent on wind velocity. Investigations on the aecial and uredial states of Melampsora In connection with the daily height measurements of the pines, the number of aecia was also counted. Both sporulating aecia and mere yellow spots were counted. The number of uredia was determined from pressed samples of aspen leaves. The samples were collected at one-week intervals after the first uredia had been observed and continued until the last week of August. At each collection, three branches were taken from each group of aspen suckers marked for growth measurement. Each branch had to bear at least 10 leaves. The number of uredia was estimated 011 these 30 leaves. Using a binocular stereomicroscope, the uredia on each of three viewing fields on each leaf were counted (cf. Kurkela 1969). Timo Kurkela 14 79.1 Several investigators have tried to estimate the amount of rust on various species of poplars when assessing their rust resistance (e.g. Schreiner 1959, van der Meiden 1961, Donaubauer 1963). In the paper by Donaubauer (1963) there is also an assessment of the value of previously developed methods. The method used in the present study is surely one of the most elaborate ones for estimating the amount of rust. This method was used since the particular purpose here was to study the development of the pathogen during the growing period, not its effect on the host plant. In order to determine how far the mycelium spreads in the tissue of the host leaf, the morphology of the diseased leaves was studied. Leaves containing uredia were fixed with a FAA-solution, embedded in paraffin and cut on a microtome. The sections were stained with the method developed by Yag a s and Ma a c z (1960). The size of the infected tissue around the uredia and the distance between the vascular bundles were measured. RESULTS Dispersal of basidiospores The number of airborne basidiospores varied considerably during different years in the Locations 1, 3, and 4. Large numbers of basidiospores were found in the air on rainy days only. The spores were observed in the air 4—6 hours after the beginning of a rain. In June of 1966, the most important time of spore dispersal and when the pine shoot growth was most intensive, precipitation did not occur in large enough quantities to be registered by the fluviograph (Figure 2). It is possible, of course, that some of the observed maxima of basidiospore disper sal in 1966 occurred due to some local thunder showers. The numbers of basidiospores were quite small, and therefore the results are very unreliable. In the summer of 1966 the same investigations were also carried out in Laihia (Loc. 2), but microscopic studies of the material collected there were not undertaken since no basidiospores were found upon initial examination of the tapes. This lack of basidiospores was apparently due to the fact that only one very small shower of rain occurred during the time of investigation. The shower was not sufficient to cause the telia to germinate and form basidiospores. The conditions of precipitation in June 1967 were favorable for the for mation and dispersal of basidiospores. The number of airborne basidiospores was not very large, however, apparently due to the low air temperature during the periods of rainfall (Figure 3). The average daily temperature during this time was less than 10 °C. The largest number of basidiospores, about 250 spores/sq.cm, was found on June 6. The crucial importance of rainfall for the dispersal of basidiospores is evident from results obtained in 1968 in Loc. I and in 1971 and 1973 in Loc. 3 and 4. The precipitation during May and June of these summers occurred intermittently with very dry days between. The most important maxima of basidiospores occurred during rainy days (Figures 4 and 6). In 1968 the maxima of basidiospores were during June 9 and 24—26. On June 9 the precipitation was 5 mm; on June 24 rain could not be registered, but the day was partly foggy with drizzling rains; and during the two following days, precipitation was several mm. June 27 was rainless, while the precipitation 16 Timo Kurkela 79.4 was great on June 29 and when the capacity of the telia to produce basidio spores apparently was exhausted since, during this time, only about ten basidiospores per cu.m. of air could be counted in spite of the very favorable weather. During the previous rains, the number of spores had been about 1 000/cu.m. The hourly maximum amounts were, of course, much higher (Figure 7), about 3 000 spores/cu.m. In Loc. 3 and 4 during 1970, 1971 and 1973 the species of Melampsora rust investigated was apparently M.larici-tremulae. In 1970 basidiospores were observed immediately when the investigations began on May 15 (Figure 5). The whole latter part of May was rainy, and therefore no con clusions can be made about the importance of rainfall for formation and dispersal of basidiospores. After June 10 no more basidiospores could be observed in spite of the rains which occurred after that date. From the results obtained during 1971 and 1973 the crucial importance of rain was quite obvious. During both these years, three distinct maxima of spore dispersal were observed (Figure 6). In the intervals between maxima, very few spores were found. Each maximum dispersal occurred during periods of rainfall. After the third maximum, spores were not detected or else the number was small in spite of favorable rainy weather. The investigations of 1971 and 1973 were undertaken with considerably more accurate instruments for measurement of wind, rainfall and dew. Con sequently, the results obtained from the spore traps could be analyzed in more detail than previously. Figures B—lo show the hourly numbers of basidiospores during periods of maximum spore dispersal in the summer of 1971. These hourly spore quantities can be related to the amount and dura tion of rainfall, to dew (i.e. occurrence of free water), and relative humidity. The first maximum of basidiospores occurred on May 22 and 23. At this time spores were airborne some 6 hours after the rainfall began; and the maximum number, about 300—400 spores/cu.m, was reached after 12 hours. After the maximum, the number of spores decreased slowly. Spores were airborne for a total of 1.5 days. Rain or fog persisted continuously for 31 hours. A second maximum of basidiospores occurred on May 28. During the previous morning there was a light rain for about five hours, registered only by the dew scale. As a result of this rain, spores could again be detected about 6 hours after the rain had begun. On the morning of May 28 about 2 mm of rain fell during four hours. Between these two days there was some water in the dew scale continuously and thus the aspen leaves on the ground with their telia did not have any chance to dry out during this time. About four hours after the second rain, large numbers of spores were dispersed into the air. The maximum spore density, 1 300 spores/cu.m, was observed seven hours after the rain began. The spore density decreased rapidly after the maximum, due to rapid drj'ing of the air and ground. Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 79.4 17 3 16568—7 3 Figure 2. Seasonal development of rust (Melampsora pinitorqua) and host trees in relation to some weather factors in Loc. 1 in 1966. A) Cumulative growth (mm) of aspen; lower portion of the solid line indicates the growth of the bud and the upper part, the growth of the short shoot; the dotted line indicates the leaf growth (length of leaf as measured along the central vein). B) The daily height growth of pine as a percentage of total length, the solid line indicates growth of the terminal leader, and the dotted line, growth of the terminals of the previous year's branches. C) Number of mature aecia as a percentage of all aecia. D) Weekly number of uredia per sq.cm leaf surface in five groups of aspen suckers. E) Number of spores per sq.cm. trapped in the spore trap (Sarvas —Wilska), solid line = aeciospores, dotted line = uredospores. F) Daily maximum, average and minimum temperature (°C) and amount of precipitation (mm). G) Wind velocity (m/s), average of observations made at 08.00, 14.00, and 20.00. Timo Kurkela 79.1 18 Figure 3. Seasonal development of rust (Melampsora pinitorqua) and host trees, Scots pine (Pinus sylvestris) and aspen (Populus tremula), in relation to some weather factors in Loc. 1, 1967. A—B) See Figure 2. C) Development of aecia, upper histogram = number of yellow spots, lower histogram = number of mature aecia. D) Weekly number of uredia per sq. cm leaf surface in four groups of aspen suckers. E) Dailj' numbers of spores, broken line = basidiospores, solid line = aeciospores, dotted line = uredospores. Lines marked with stars indicate results obtained 79-t Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 19 Figure 4. Seasonal development of rust and host trees in relation to some weather factors, Loc. 1, 1968. A -G) As in Figure 3. with the Sarvas —Wilska pollen trap while lines marked with circles indicate results obtained with the TTirst spore trap. F and 0) As in Figure 2. Timo Kurkela 79.i 20 Figure 5. Seasonal spore dispersal of Melampsora sp. (mainly M. larici-trenmulae) in relation in to some weather factors in Loc. 3, 1970. 79.-1 Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 21 Figure 6. Dispersal of basi diospores of Melampsora sp. in relation to some weather factors in Loc. 3, 1971. The spore data were obtained simultaneously with two traps. In the histogram in dicating length of daily wet period, the black part in dicates duration of rain and the white part, the sum of duration of rain and dew in hours. 22 Timo Kurkela 79.1 Figure 7. Basidiospore dispersal of Me lampsora pinitorqua in relation to precipita tion, temperature, and relative humidity in Loc. 1, June 25—27, 1968. The third spore dispersal maximum occurred on June 12 and 13. The first spores were trapped after about 3 hours; after 6 hours the spore density rapidly increased and reached the maximum, ca. 450 spores/cu.m in one trap and over 800 spores/cu.m in the other trap, some 12 hours after the rain began. The almost continuous rain lasted for 41 hours, and considerable numbers of spores occurred in the air for almost two days. During these three periods of maximum spore occurrence, the capacity of telia to produce spores seemed to be completely exhausted since, after the heavy rain of June 18, only a few spores were trapped. Results obtained in the spring of 1973 support the conclusions, based on previous years' results, about the most important factors influencing forma tion and dispersal of basidiospores (Figure 11). In spite of the early spring, the temperatures before the beginning of May were not high enough for formation of spores. During the first days of May, the days became warmer, and after the rain on May 6, the first basidiospores were observed. The second maximum occurred as a result of the rain on May 14. After this, it rained for several consecutive days, and spores seemed to occur less fre quently. Apparently, the capacity of telia to produce spores had already decreased considerably. On May 17 a clear maximum of spores was observed, although it was much smaller than the previous ones. The spore maxima on May 6 and 14 were observed 13 and 10 hours after the rains began. During these maxima, the air temperature fluctuated between 5 and 10 degrees. The presence of water or abundant moisture is crucial for the formation of basidiospores; but, on the other hand, it may be possible that rain inhibits the release of the spores or washes them directly to the ground. In any case, 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 23 Figure 8. Hourly dispersal of basidiospores (Meampsora sp.) in relation to various weather factors in Loc. 3, May 21 —24, 1971. The number of basidiospores has been indicated for two replications. greater numbers of spores have occurred in the air only after rains. The changes in air humidity may have promoted release of the basidiospores. When the release of spores was at a maximum, the relative humidity of the air was rather high due to the rainy weather. The relative humidity may have varied considerably (100 —90 %), however, without appreciably affecting spore density. Apparently, relative humidity, as measured at 2 meters above the ground in a weather chamber, is not a suitable variable 24 Timo Kurkela 79.i Figure 9. Hourly dispersal of basidiospores ( Melampsora sp.) in relation to some weather factors iti Loc. 3, May 26—29, 1971. For legend see Figure 7. for explaining formation and release of basidiospores in the ground litter. The same appears to be true for temperature. Although experiments in the laboratory clearly indicated an increase in the rate of spore release (Kur kela 1973 a), the same effect of increased temperature could not be ob served in the field. In the field considerable numbers of spores could be released even at very low temperatures (less than +5 °C). This was not ex Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 79. t 25 4 16 568 —73 Figure 10. Hourly dispersal of basidiospores (Melampsora sp.) in relation to some weather factors in Loc. 3, June 11—14, 1971. For legend see Figure 7. pected, judging from the results obtained in laboratory experiments. The two results need not be contradictory since the temperature on the ground litter may, sometimes after rains, have been higher than the temperature measured in the weather chamber. The effect of wind velocity 011 spore release was even less definite than that of temperature. Timo Kurkela 79.4 26 Figure 11. Basidiospore density (spores/cu.m of air) of aspen rust (Melamysora sp.), wind velocity (m/s), temperature measured in a weather chamber (°C), relative humidity (RH, %), precipitation (mm/h), and length of wet period caused by rain and dew (h, thick black horizontal line). In Loc. 4 during three four-day periods in May 1973. Dispersal of aeciospores and uredospores The number of aeciospores dispersed in the air depended primarily on the extent to which the basidiospores had been able to infect pine shoots or larch needles and, furthermore, on how much the aecia developed after infection. The variation in the numbers of aeciospores from year to year may be Epiphytology of Melatnpsora Rusts of Scots Pine and Aspen 79.4 27 regarded as depended primarily on these two factors. Observations on the shoot and needle development of aecial hosts of Melampsora in Loc. 1 showed that larch needles and pine shoots reached a susceptible stage about 15th of May and during the first half of June respectively. Aeciospore dispersal started during the second half of June after the first aecia had developed on pine shoots and lasted 20—30 days. Inspection of the average daily number of aeciospores (Fig. 2—5) shows, especially in the results of 1967, that during high temperatures the numbers of aeciospores have been greatest. Sudden showers can also rapidly increase the number of spores in the air, as happened on July 4 and 11, 1967 (Fig. 12). Since the thundershowers often were preceded by strong gusts of wind, it was usually impossible to separate the effects of wind and rain. The relative humidity of the air was not included as a variable in the graphs (Fig. 2 —5) describing the dispersal of spores and development of the disease during the growing season. If the air humidity in general has any influence on release and dispersal of aeciospores of Melampsora, then the correlation is clearly negative. The number of spores fluctuated during different periods of the day (Fig. 13). The spore density of pine twisting rust was at a minimum in the middle of the night, during which time there usually is dew and the Figure 12. Dispersal of aeciospores of M. pinitorqua in the summer of 1967 in Loo. 1 in rela tion to precipitation, temperature and relative humidity of the air. The shaded areas indicate the time between sunset and sunrise. 28 Timo Kurkela 79.1 air humidity is at a maximum. The number of spores began to increase about 06.00 when the dew started to dry and reached a maximum between 09.00 and 11.00 when the normal dew had completely evaporated. In Tuu sula (Loc. 3) the average maximum spore density of the larch rust did not occur until late afternoon at 17.00. The difference between this result and that of Ikaalinen (Loc. 1) may be due to the limited data from Loc. 3, but may also be due to local conditions. In Loc. 1 the aecia of pine twisting rust were located in the tops of 0.5 —1.5 m high saplings and thus were exposed immediately to insolation and wind, which dryed the dew rapidly. By contrast, the aecia of the larch rust in Loc. 3 were located on the lower branches of some 6 m high larches which were not reached by continuous in s olat ion. Dispersal of uredospores commenced in Loc. 1 at the beginning of July and in Loc. 3 at the end of June. The uredospores, similar in this respect to the aeciospores, seem to disperse when dry. Their maximum spore density occurred between 13.00 and 15.00 (Fig. 13). The average maximum of spore density for the whole growing season occurred at 13.00 during 1966 and 1968. On the data from 1967 the variation in spore density was calculated separately for July, August, and September. This was done in order to find out whether the gradual change in various weather components would be accompanied by corresponding changes in the number of uredospores as fall approached. No significant differences between various months were ob served. The maximum average spore density for each of the three months occurred at 15.00. The spores were counted at every odd-numbered hour. In Loc. 3 in 1970 the maximum spore density occurred before noon, at 11.00. The minimum density occurred between 24.00 and 06.00. Deviations from the regular pattern of variation were caused by showers accompanied by gusts of wind. The fact that the daily maximum during the whole dispersal season in Loc. 3 in 1970 occurred at 11.00 is thought to be due to unusually gusty winds and rain showers. On August 23 an exceptionally high spore density occurred. It can be explained only by the coincidence of a very strong wind and a rain shower. The rain, however, could not be registered on the fluvio meter. On this day the spore density exceeded 6 000 spores/cu.m/h (Tig. 14) compared to the general daily maximum which was seldom more than 1 000 spores/cu.m/h. Since the diurnal periodicity of dispersal for both aecio- and uredospores was very obvious, it was rather difficult to distinguish the effects of periodic weather factors on numbers of spores in the air. When the effects of various weather components are examined within a 24 hour period, the air tempera ture, wind and insolation, which was not measured in this connection, appear to be positively correlated, while relative humidity of the air and dew seem 79.i Epiphytology of Melampsora Rusts of Scots Pine and Aspen 29 Figure 13. Average daily variation in number of Melampsora sp. aecio- and uredospores as a per centage of the highest total count for an hour. A) Diurnal periodicity of aeciospores (M. pinitorgua) dispersal in Loc. 1 in 1966—1968. B) Diurnal periodicity of spores (Melampsora sp.) in Loc. 3 in 1970, a = aeciospores, b = uredospores. C) Diurnal periodicity of uredospores (M. pinitorqua) in Loc. 1 in the summer of 1967, a = July, b = August, c = September. D) Daily average period icity of uredospores of M. pinitorqua in Loc. 1 in 1966 and 1968. to be negatively correlated with the density of aecio- and uredospores in the air. Table 1 presents the correlation matrix for the variables used in the regression analysis (except for variable xlO which was not statistically signifi cant in any of the models tested). The spore density is most strongly corre lated with the number of uredia. This, however, is true only for the data of 1966. For temperature the only significant correlation with the daily spore density was obtained in 1968. In this year the density was positively correlated with the average temperature for the coldest period of the day. To some Timo Kurk e 1 a 79.1 30 Figure 14. Dispersal of uredospores in relation to rain, wind velocity, air temperature, and relative humidity in Loc. 3, August 23 —26, 1970. extent the density and the temperature appear to be negatively correlated, which simply is due to the fact that, along with the colder weather as fall approached, the number of uredia and uredospores increased logarithmically. A statistically significant correlation between wind and spore density was obtained only in 1968. In addition, the matrix shows the low correlations 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen 31 Table 1. Correlation coefficients between the number of uredospores trapped, the number of uredia, and some weather factors (for explanations, see pp. 12—13). between the temperature at the coldest period of the day and the other temperature variables. This is due to the fact that the average temperature for the coldest part of the day includes temperature readings before mid night of one day and after midnight (i.e. early morning) of next day. In the regression analysis, data for each year were analyzed separately. The strongest correlations between spore density (x 2) with other variables were obtained with the following equations: As expected, the variables x s and x 9, derived from the number of uredia, best explained the variation in number of spores. In 1966 and 1968 the variables x 9 and x s , respectively, were statistically significant. In 1967 the 1966: y A -f- Bx 6 -\-Cx a, r 0.58, d.f. = 37 1967: y A**-\-B**x& -\-Cx 7-\-D**x s , r = 0.60, d.f. = 25 1968: y A*-\-B***Xi-\-C*x6-\-T)x 1-\-Ex 9, r = 0.55, d.f. = 33 *** statistically significant, at the 0.1 % level of probability. ** = significant, at the 1 % level of probability. * = significant, at the 5 % level of probability. X, X, a*« 1966 0.54 6 x 2 1967 0.424, 1968 0.317 1966 0.918 0.5 60 x 3 1967 0.841 0.249 1968 0.952 0.296 1966 —0.335 —0.161 —0.523 x 4 1967 —0.499 0.041 —0.447 1968 —0.429 0.293 —0.444 1966 —0.283 — 0.240 —0.498 0.795 x 5 1967 —0.254 0.2 01 —0.363 0.786 1968 —0.171 0.416 —0.280 0.600 1966 —0.313 —0.111 —0.451 0.957 0.613 X 6 1967 —0.631 — 0.O69 —0.466 0.9 42 0.575 1968 —0.436 0.180 — 0.370 0.912 0.269 1966 —0.060 0.116 —0.051 —0.124 — 0.140 —0.084 x-j 1967 —0.234 0.130 —0.231 0.126 0.138 0.O96 1968 0.145 0.375 0.111 0.258 0.12 7 0.215 1966 0.931 0.566 0.999 —0.521 —0.490 —0.454 —0.041 x s 1967 0.849 0.253 0.999 —0.440 —0.35 2 —0.46 7 —0.239 1968 0.937 0.295 0.999 —0.438 —0.291 —0.351 0.111 1966 0.954 0.578 0.985 —0.521 —0.470 —0.465 O.ooi 0.9 70 ,r 9 1967 0.855 0.249 0.987 —0.405 —0.304 —0.451 —0.270 0.991 1968 0.871 0.284 0.976 —0.409 —0.323 —0.284 0.1O4 0.986 1966 number of observations 41 1967 number of observations 43 1968 number of observations 29 Timo Kurkela 79.j 32 variables derived from the number of uredia were not significant in the regression equations but the variable xl} the number of days from the first occurrence of uredia, was very significant. Relatively little can be explained by the temperature variables. During all years the average daily temperature explained less than the average temperature of the coldest or warmest period of the day (x 5 and x B ). In 1967 the factor of variable x 6, and in 1968 the factor of variable x 5 had some significance. When the regression analysis was made for each month, then the significance of variable x 6 was increased in the equation for 1967. This factor became very significant for July—August, and the correlation coeffi cient for the whole model was 0.7 o (d.f. = 22). In July and early August of 1967 the daily average and maximum temperatures were considerably higher than in 1968 (Figures 3 and 4). The high temperatures seem to have increased the formation and release of uredospores. On the other hand, it is possible that the colder nights of 1968, compared to the previous year, would have been a factor limiting the formation of spores. This explana tion also has its weakness in that during 1966 the night temperatures at the end of August were even lower, but the number of airborne uredospores reached its maximum (Fig. 2). At the end of August in 1968 the weather was very warm and no rain occurred. During this time none of the factors for any of the variables reached high statistical significance. The factor of the wind variable provides the best explanation. It was almost significant, and the correlation coefficient of the whole regression equation was 0.73 (d.f. = 10). The data for these 14 days contained, however, only 1 143 uredospores. An analysis of the total data for the different years did not indicate that the effect of wind on num bers of spores would have been statistically significant. It is understandable that the wind had a low correlation. The wind hardly ever (with, perhaps, the exception of the end of August, 1968) was so low that it would have limited the release and dispersal of the spores. On the other hand, the sudden gusts of wind, which were able to release large numbers of spores, usually occurred in connection with thundershowers. Thus the effect of wind was difficult to determine. The wind velocity used in the calculations was the average of the observations per day, which already by definition excludes the possibility of detecting the effect of gusts of wind in the analysis. The temperature, in a similar situation to that of the wind, was closely related to the rains. As a result of a rain, the temperature usually dropped, and on the other hand, prior to thundershowers, it was usually very warm. The hourly maximum spore densities usually occurred when there first had been warm and sunny weather followed by sudden thundershowers in con nection with strong gusts of wind. Long periods of rain or rain during several consecutive days usually caused a definite drop in the numbers of aecio- and 79.i Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 33 5 16568—73 uredospores. This drop may also have been partly due to a drop in the temperature caused by the rain. In order to consider the effect and varia tion of these short-duration weather components in the regression analysis, the analysis should be based on hourly observations, and the mode of action of each factor should be known in detail. Twisting rust on pine Seasonal variation of rust incidence Tables 2 and 3 indicate the variation in amount of twisting rust in Loc. 1 during 1965—1968. The summer of 1965 was, compared to the previous growing season, more favorable for development of the pine saplings. Aecia of twisting rust occurred on the shoots on an average of 2.2 and 1.5 aecia/ dm. During the next year, 1966, there was somewhat more rust per shoot, but the number of aecia per dm was smaller than during the previous year. In 1967 the incidence of rust reached a maximum in Ikaalinen. The amount of rust was about fuorfold compared to the previous year. In 1968 the amount decreased so much that there was not even a tenth of the amount which had been present in 1967. In 1969—1972 no systematic observations were Table 2. Incidence of pine rwisting rust on the terminal leaders of Scots pine in Loc. 1 during the summers of 1965—1968. Year 1965 1966 1967 1968 Number of trees surveyed ! 25 47 30 10 Total length of terminal leaders, dm — average length, dm 77.61 1.50 116.50 2.49 84.17 2.81 18.57 1.86 Number of aecia — total number including yellow spots — aecia matured 94 55 a 156 454 400 11 6 Number of aecia per terminal leader — total number — aecia matured 3.76 2.20 3.32 15.13 13.33 1.10 0.60 Number of aecia per dm — total number — aecia matured 2.50 1.46 1.34 5.39 4.75 0.59 0.32 Number of trees — with healthy terminal leader — with no matured aecia 9 12 19 0 0 6 6 a) — = no record Timo Kurkela 34 79.1 Table 3. Incidence of pine twisting rust on shoots of one year old branches of Scots pine in Loc. 1 in the summers of 1966—1968. made on the incidence of rust. In the fall of 1969 and 1970 the pine saplings on the experimental plots in Loc. 1 were examined, but no symptoms of rust could be detected. Also, during the following years, no serious epiphytotics occurred, but some rust was observed in various parts of the country. The annual variation in rust incidence was best explained by the occur rence of rains during the growth of the pine shoots. Figures 2—4 show the daily height growth of the pine in Loc. 1 during 1966—1968. At the begin ning of growth, before 10—30 % of the total height had been reached, the shoots were still covered with the fascicle scales. These scales seemed to completely prevent rust infection. Only when the surface of the shoots had been exposed were they susceptible to infection by the basidiospores. In the experiments conducted in the greenhouse the pines became resistant only when height growth was almost completed. Consequently, the pine shoots were susceptible to rust for some 20 days, between June 5—25. The amount of twisting rust was strongly correlated with the rains occurring during these days. During 1964 and 1967 the most important rains in June occurred at a time favorable for rust, causing a very heavy epiphytotic. During 1965, 1966, and 1968 the rains during pine shoot growth were not very heavy, but they were heavy enough to result in formation of basidio spores and a medium to light infection of the pine shoots. June of 1969 was Year 1966 1967 1 968 Replications I il J it I Number of trees 47 47 30 30 10 Total length of shoots, dm 72.99 76.62 55.51 52.92 16.26 — average, dm 1.55 1.03 1.85 1.76 1.63 Number of aecia — total number including yellow spots .. — a — 157 146 3 — aecia matured 32 36 135 131 1 Number of aecia per shoot — total — — 5.23 4.87 0.30 — matured 0.68 0.77 4.50 4.3 7 0.10 Number of aecia per dm — total — — 2.83 2.76 0.18 — matured 0.44 0.4 7 2.43 2.48 0.06 Number of health}' shoots 2 4 8 — with no matured aecia 32 31 4 4 a ) — = no record 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 35 not particularly lacking in rain, but the rains seem to have occurred when the shoots were not susceptible to infection. The next year, 1970, no rains occurred during the critical period, thus causing the pine twisting rust to disappear from most of Finland. Information about the rains during different years and months are available in the Meteorological Yearbook of the Finnish Meteorological Institute (Finnish Meteorological Office 1965—1967, Finnish Meteorological Institute 1968—1970, 1972). In 1966 rain was not registered at all during the time of most intensive growth of pine. The rains during June 3—7 were too light to allow the spread of pine twisting rust. At this time the pine shoots were still protected by the scales of the fascicles. The fact that infection did not take place during these rains can be deduced also from the observation that the first aecia did not occur until June 25. On June 14 and 16 some small thundershowers may have occurred (Finnish Meteorological Office 1966). These, however, were not registered on the fluviometer, at the study area but they could have caused some infection of the pine shoots, which probably resulted in the aecia observed on June 25. Some infection also may have occurred later, e.g. on June 22 when a 0.5 mm rain was registered. The spore counts obtained in 1966 from the Sarvas— Wilska pollen trap were too inaccurate for determining the probable time of infection. The severe epiphytotic of 1967 was a result of a perfect coincidence of pine shoot growth and rain. It rained on June 1, but the pine shoots could not yet be infected. After this, it was warm for a couple of days when the daily shoot growth almost reached its maximum. On June 5 an almost con tinuous period of rain began and lasted for seven days. For a long time the average temperature was below 10 °C. The low temperature caused an almost complete cessation of the pine shoot growth (Figure 3). Since the pine shoots remained susceptible to infection for a long time, the infection was unusually intensive even if the temperature was considerably below the optimum for development of the pathogen (cf. Kurkela 1973 a). The first aecia were observed on June 19. If the first infections are assumed to have occurred on June 6, then it had taken 14 days for the aecia to develop. The cold weather could, of course, have slowed their development. No new infections resulted from the rains which started on June 21 since basidio spores were observed in the air at this time. As was stated in the report on dispersal of basidiospores, two rains, which resulted in the formation of basidiospores and fascilitated infection, occurred in 1968 during the shoot growth of the pines. The first of these rains (5 mm) was on June 9—lo. Enough moisture for infection occurred, however, during a relatively short period, resulting in a fairly light infection of the pine shoots (Figure 4, Table 2 and 3). The first observations on aecia formation were made on June 19, and on June 23 mature aecia were found. Timo Kurkela 36 79. t On June 18 and 19 small showers, which did not result in measurable num bers of basidiospores, occurred. The rain on June 25 and 26 resulted in intensive formation of basidiospores, but new aecia were not formed. Ap parently, the pine shoots bad already developed resistance against infection. Effect of wind on the 'positions of aecia on pine shoots The position of aecia on the different sides of the pine shoot was clearly dependent on the wind direction at the time of basidiospore dispersal. Since the rust mycelium is limited to the immediate vicinity of the aecia, the positions of the aecia indicate the directions from which the basidiospores have arrived. Figure 15 indicates the relative proportions of aecia positions on the pine shoots in Loc. 1 in 1965 and 1966. The proportions were calculated on the basis of 500 observations. The predominating directions of basidio spore arrival in Loc. 1 in 1965, as well as in Parkano about 30 km away. Figure 15. Number of aecia on different sides of pine shoots in percentage of total number, in Loc. 1 in the summers of 1965 and 1966. Epiphytology of Melampsora Rusts of Scots Pine and Aspen 79.4 37 were southwest and south. In Parkano some aecia also were located on the northern side of the shoots. The low pressure systems bringing rain to Finland usually arrive from the southwest. During the summer of 1966, at the same location as previously described in Loc. 1, most of the basidiospores had arrived from directions between west and north. During this summer the rains at the time of shoot infection were not caused by low pressure systems. The spores were formed and dispersed only during or after small thunder showers. On the locations examined, aspen leaves bearing telia were found all around the experimental plots. The occurrence of more aecia on some sides of the pine shoots than on others is an indirect indication of how crucially important weather factors of very short duration may be for infection. If such a strict dependence would not exist the aecia would probably be more evenly distributed around the pine shoots. In connection with investigations of this kind, it would be important to register wind direction, but there were no possibilities for such registration during this work. Growth stage and rust resistance of pine The infection of pine shoots with basidiospores of Melampsora pinitorqua during the pine growth phase resulted in the formation of aecia on the shoots. A relatively large number of aecia also developed on growing needles. When 99.9 % of the shoot growth was completed, aecia were formed only on needles. Inoculations performed later when no shoot growth was observed resulted only in a few yellow spots. These spots were aecial primordia but never did complete their development. In the earlier sets of inoculation the Table 4. Inoculation of pine saplings with basidiospores of Melampsora pinitorqua. Shoot length. °o of final length Time from planting to inoculation Number develped Shoots of aecia n saplings» Needles Time required for opening of the first aecia, days 57.1 0 38 0 11 58.0 0 67 1 11 71.5 3 42 13 11 71.7 4 2 5 14 87.1 6 15 35 12 95.5 9 11 23 12 95.5 14 10 5 11 98.8 14 11 35 13 99.91 18 b 14 13 100 22 0 100 26 0 0 — a) Every set consisted of 10 seedlings b) Yellow spots on ly 38 Timo Kurkela 79.4 yellow spots could be detected on the shoots 2—4 days before the aecia opened. Before opening, the yellow spot was surrounded by droplets of liquid with pycnidia forming pycniospores; i.e. fertilizing sporidia (cf. Gäum an n 1964). The opening of the aecia occurred 11 —14 days after inoculation. The results of these experiments are presented in Table 4. Correlation between rust incidence, shoot length, and height of pines Since the basidiospores of a rust fungus land at random on different surfaces, the longer the shoot is, the higher the probability of infection. The correlation between the shoot length and the number of aecia developed on it was studied using the data of 1967. The correlations of shoot length with numbers of aecia (i.e. the number of mature aecia only and counts of aecia which included mature ones and yellow spots) were low (r = 0.43 and 0.48) for the data which included terminal leaders. For data on terminals of branches the corresponding correlations were r = 0.61 and 0.64, respectively. The combined data resulted in a correlation of 0.7 5 and 0.7 7. The highest Figure 16. Relationship between shoot length and number of aecia on pine shoots in the summer of 1967. The rings indicate number of yellow spots, and the black dots indicate the number of mature aecia on the shoot. The line connects observations from one shoot. The thick solid line is the re gression of number of aecia on shoot length, and the broken line is the regression of number of yellow spots on shoot length. Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 79.4 39 Figure 17. The regression of number of aecia on the two uppermost whorls of branches and the terminal leader on pine sapling height, in Loc. 1 in 1964. correlation for the combined data was obtained for the regression model y = A*** + Figure 16 indicates the relationship between shoot length and number of aecia. Consequently, on the branch terminals the number of aecia seems to be more dependent on length than on stem termi nals. The stem terminals were about three times more susceptible than the branch terminals. In 1965 on some 25x25 m large plots in Loc. 1 the number of aecia formed during the previous summer was counted on the main shoot and branches of the previous year as well as on the shoots of the one year old branches. When the saplings were less than 1.5 m high, the number of aecia was linearly correlated with the size of the sapling. Figure 17 presents the results from two plots. This linear relationship was more irregular if no aspen occurred on the plot or in its immediate vicinity. Interaction of the development of pine and rust The rust seemed to reduce the growth of the pine shoots to some extent. In the 1966 and 1967 data, the shoots, which later became severely infected, started growth slightly more vigorously compared to those remaining healthy or less infected. After the establishment of the fungus daily relative 40 Timo Kurkela 79.4 growth in the infected shoots was less than that in the healthy shoots. For this comparison the relative growth was used, obtained by dividing one day's growth by total length measured the previous day. Even if the dif ference in average growth caused by the rust seemed clear, no correlation was found between rust severity (number of aecia/dm) and growth of indi vidual trees. Length measurements of severely infected shoots were difficult and more inaccurate due to the twisted shoots as compared to the healthy ones. Since the number of saplings on the experimental areas did not change significantly during 1967 and 1968, the number of aecia per tree could be regarded as an index of the number of aecia in the area (Tables 2 and 3). Since during both years the method of spore trapping was the same, the measured spore densities are comparable. In 1967 the total number of aeciospores was 5 523, and in 1968, 443 spores were trapped. Even though there were ten times more spores in 1967 than in 1968, the number of spores per aecium seems to have been only half the number found in 1968. This difference may have been due partly to the effect of weather factors. It is also possible that in 1967 the aecia may have been too close to each other to get enough nutrients from the shoots for spore production. The sparsely distributed aecia also seem to cause relatively more severe damage than those which are densely distributed. This may be deduced from the fact that the local effect of only one aecium may be sufficient to kill the shoot above the point of infection. During the severe rust years of 1964 and 1967 in Loc. 1, almost all the terminal leaders of pine were killed on the experimental area as well as elsewhere in western Finland where pine sapling stands with plenty of aspen suckers were found. During other years the damage was less severe. As a result of the severe rust year of 1967, about 50 % of the pine ter minals were dead by August 17. This is thought to be a direct result of the action of the pathogen. During the following winter, the terminals continued to die off so that next spring about 90 % of the terminal leader and branch terminals had died. Death during the winter was often connected with the effects of various weather factors. Many of the shoots infected by the rust in the summer were too weak to endure the strain caused by winter snows. Some shoots which were still alive in the fall died during the winter and spring. The most common reason for death seemed to have been the resin flow and impregnation of the rust-caused wound, resulting in blockage of the phloem connections. It is also possible that the needles on the infected shoots were not resistant enough to desiccation in the winter. The kind of damage that developed depended quite strongly on the phase of shoot growth at which infection occurred and aecia developed. Early in fection resulted in death of the shoot already during the growing season. In some mild cases the shoots were only bent. Infection occurring late during 79.i Epiphytology of Melampsora Rusts of Scots Pine and Aspen 41 6 1650 B—7 I shoot growth usually did not result in twisting or immediate death of the shoots but resulted in wounds healing by the end of the summer. The wounded places, however, seemed to be very susceptible to breaking by snow in the winter. The recovery of the pines after rust damage and replacement of the dead shoots were very much dependent on the severity of the attacks. A mild infection does not always cause death of the terminal leader. Even if the leader dies, some of the healthy shoots on the current whorl may already partly replace the leader in the same summer. All the shoots at the top of a sapling may die as a result of severe infection. In such a case the terminal may be replaced by a lower branch or by a shoot developed from the bud of a short shoot (Figure 18). In this case two or three growing seasons may pass before the sapling reaches the height to which it would have developed during the year of the rust, had it not been infected. Figure 18. The top of a pine sapling severely damaged by pine twisting rust. As a result of the intensive infection, all shoots have died. During the growing season following the year of damage, shoots have grown out of the short shoot to replace the leader. Incidence of rust on aspen leaves When aeciospores were released from the aecia of M. pinitorqua on the pine shoots, the aspen leaves already were fully developed. In the pine sapling stands or in their vicinity the first uredia were observed oil aspen leaves in Loc. 1 at the beginning of July. The primary infection of the leaves seemed to have been caused bv the aeciospores developed on Timo Kurkela 42 "79.1 pines growing on the experimental plots. Uredia were not observed 011 aspen leaves before the maturation of aecia but were found only 10—20 days after the aeciospores had started to disperse. Consequently, it is obvious that the rust did not overwinter in the uredial stage. Neither could remote dispersal of uredospores have caused the primary infection of the aspen leaves since the first uredospores were trapped at the same time as the first uredia were observed. When aspen leaves were inoculated during rainy weather with aeciospores obtained from the pine shoots, the uredia developed in 10—14 days. On the other hand, it has to be noted that, depending on weather conditions, M. rostrupii Wagner (cf. p. 49) and M. larici-tremulae may have been able to cause the uredial state on the aspen 15—30 days earlier than M. pinitorqua, since these two species of rust compared to .1/. pinitorqua develop their aecial state earlier. The number of uredia initially increased geometrically (Figures 2—4) due to infection by the ever-increasing number of uredospores. In both 1966 and 1967 the number of uredia of the aspen leaves at the end of August had reached approximately the same level, about 30 —50 uredia/sq.cm. Tn 196K the number of uredia was considerably smaller compared to previous years, about 1 uredium/sq. cm. The summer of 1968 was relatively cool and rainy, thus inhibiting the continuous multiplication of the uredial stage on the aspen leaves. According to the observations, aspen rust occurred rather sparsely in the fall of 1968 all over the western and northern parts of Finland. During the following three years (1969 —1971), aspen rust was very sparse. It was found only in a narrow zone along the southern coast and sporadically in the vicinity of larch stands. Most likely, the rust observed then in the southern parts of the country was Melampsora larici-tremulae or M. rostrupii, since the aecial stage of these species was not uncommon during these years, but pine twisting rust could hardly be found at all. In the fall at the end of the growing season the telia of Melampsora developed. Their number was 2—5 times greater than that of the uredia. The mycelium around the medium was limited to the yellow leaf area surrounding it. The yellow color of the area was due to the fact that the chloroplasts had disappeared from the cells affected by the mycelium (Figure 19). The veins of the leaves limited the spread of the mycelium in the tissue (Figures 19 and 20). To some extent, the mycelium seemed able to bypass the thinner veins. The distance between veins thicker than 50 % of the leaf thickness varied from 0.3 6 —1.2 3 mm and averaged 0.7 mm. Consequently, the mycelium which developed from one basidiospore could infect the tissue on an area of 0.4—1.2 sq.mm. From this it can be concluded further that on an area of 1 sq.cm there are about 100—200 areas, delineated by the veins, which can be infected independently by a single spore. Usually all these areas are not infected. 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen 43 Figure 19. Microscopic sections from aspen leaves infected by the rust. A) Abundant intercellular mycelia in an infected leaf, a) haustorium connected by a thin neck to a mother cell outside the host cell. B and C) Magnifications of the haustorium, b) the mother cell of the haustorium, c) the haustorial neck, d) haustorium, e) wall of host cell, and f) nucleus. D) Cross section of an aspen leaf with a Melampsora uredium on the lower surface. The chloroplasts have disappeared from the leaf next to the uredium. In the center of the picture is a vein which has inhibited growth of the mycelium. Healthy tissue to the left of the vein. A) x 300. B and C) x 800. D) x 80. Figure 20. Distribution of the aspen leaf veins of various thicknesses. The thickness of the vein expressed as percentage of the leaf thickness. The shaded areas indicate the number of veins of each thickness class which ones the mycelium had passed. 44 Timo Kurkela 79.4 There was abundant intercellular mycelium in the infected tissue. At places in the tips of the mycelium there were intensively-stained cells which proved to be mother cells of haustoria. In the same host cell there could even be several haustoria, which were connected to the mother cells by a narrow neck (Figure 19). The haustoria appeared to be similar to those studied by Long o and Na 1 di n i (1972) and with those of the rust M. Uni (Ehrenb.) Lev. described by Littlefield (1972). DISCUSSION Dispersal of basidiospores and infection of pine The dispersal of the basidiospores of Melampsora jnnitorqua was studied during June of three consecutive years: 1966, 1967, and 1968. The study was begun when the buds were still covered with scales, and consequently, the shoots were unsusceptible to infection. Basidiospore dispersal may have oc cured already before the study began. The maximum spore densities and total numbers of spores were extremely varied during different years. Comparison of the average numbers of spores for different years is complicated by the fact that during 1966 and 1967 the spore counts were obtained with the Sarvas—Wilska pollen sampler, while during later years the counts were obtained with the Hirst spore trap. Since the basidiospores do not have any characteristic features except for the rounded shape, size and a faint, rapidly fading yellow color, their identification was fairly inaccurate on the vaseline covered, cellophane plates from which one could not make ordinary micro scopic slides. During microscopic examination the count might easily have included other particles resembling the spores. This apparently happened in the examination of the material from 1966. When counting spores in 1967 the work was done more critically. Then again, some of the spores may have been uncounted. The numbers of spores counted in 1966 and 1967 were approximately the same, but when considering the abovementioned counting difficulties, it is very probable that the number of spores in 1967 was really much larger at the time when pine was susceptible. The slight effect of air temperature on the airborne basidiospores concurs with the results of laboratory experiments (K urk e1 a 1973 a), according to which the formation and release of basidiospores occurs over a wide temperature range. According to present knowledge, the basidiospores are actively released (K leb ah n 1904, Die tel 1912, Prince 1943, Savi 1 e 1965). and in addition, the spores are so minute (0 6—lo fi) that even the lightest air current may move them. Therefore, the correlation between wind velocity recorded on an anemometer and the spore density may be mere coincidence. It may be speculated that the vertical air currents, created when the air becomes warmer, are of importance for dispersal of basidiospores since they are formed on aspen leaves lying on the ground Timo Kurkela 79.i 46 and the basidia are not capable of actively ejecting them very far into the air. The obtained results are not in conflict with such a hypothesis; but, on the other hand, neither can it be proven. The dispersal of rust basidiospores has been found generally to occur during high relative humidity of the air. In more southern latitudes, where more dew is formed during the night, a diurnal periodicity may be observed with the maximum around midnight (Carter and Banyer 1964, van Ars del 1967, Snow and Froelich 1968, Pady and Kra mer 1971). Even in areas favorable to dew condensation, the formation and dispersal of basidiospores appears to be most intensive when rains have prolonged the moist period (H ir t 1942, Snow and Froelich 1968). In general, the dispersal of basidiospores occurs most intensively, or even exclusively, during nights when there is dew (Hirst 1953, Gregory and Stedman 1958, Sreeramulu 1959, 1963, Wood and Schmidt 1966, Shanmug a n a t h a n and Arulpragasam 1966, de Gr o o t 1968). All basidiospores are not, however, dispersed when moist; but, for instance, a reduction in relative humidity may cause release of the spores (McCracken 1972). Sylven (1918) already found that the incidence of pine twisting rust was crucially dependent on the rains in May and June. Also, the observations made by Klingström (1963) indicated the importance of rains for spore formation. The germination of telia of Melampsora seems to be con trolled by an internal rhythm regulated by various weather factors. This results in germination of the telia simultaneously with the height growth of the pine shoots (Klingström 1963, Long o et ai. 1970). In the pres ent study the number of airborne basidiospores was reduced to insignificant amounts after mid-June. Exceptional weather may cause irregularities in the germination rhythm of the telia. Regler (1957) found that telia of Melampsora may, as an exception, germinate in the fall, which reduces the possibilities for an increase in rust the next spring. Rains have been found to have a crucial influence on formation of basidiospores and the infection caused by several species of Cronartium (H ir t 1942, van Ar s del et ai. 1956, van Ars del 1967, Nighswander and Pat ton 1965, Snow and Froelich 1968, Snow et al. 1968). By means of weather forecasting and by following the development of the telia, it is possible to predict the risk of infection by Cronartium fusiforme with a 2—3 day interim (Davis and Snow 1971). For some species of Gymnosporangium rains may not be of the same importance as for Melampsora and Cronartium. The telia of Gymnosporangium are often surrounded by a very moist, gelatin-like matrix. Thus, dew during the night may be enough for formation of the spores. This is indicated by the diurnal pattern of release with a maximum at midnight observed by P a d y and Kramer (1971). The basidiospores 79., Epiphytology of Melampsora Rusts of Scots Pine and Aspen 47 of Gymnosporangium can cause infection on host plants even at considerable distances, such as 10—12 km (MacLachlan 1935) and even as much as 23 km (Parmelee 1968), apparently because the spores can be formed during a comparatively short, moist period but possibly also because of their relatively good survival capacity. The basidiospores of Melampsora and Cronartium appear to die rather easily if the relative humidity of the air decreases below the saturation point (S chafra nsk a j a 1940, Hi r t 1942, Nighswander and Pa 11 o n 1965). Obviously the pine twist ing rust cannot spread very far from the source of inoculation, the aspen suckers, due to low survival of basidiospores (Rennerfelt 1954, Schafransk aj a 1940, T roschanin 1952, Kard e 1 1 1962, Dur ri e u 1967). The dispersal distance in each case is very much depen dent on local conditions. Even during very favorable conditions, rust cannot occur more than 200—250 m from aspen suckers (Schafransk a j a 1940, T roschanin 1952). Dispersal of aeciospores and uredospores Aecios por e s. Dispersal of rust aeciospores has not been studied very extensively (P ad v 1971 a). To my knowledge not a single study has been published about the dispersal of the aeciospores of Melampsora. K r a m e ret al. (1968) found in their studies a distinct diurnal, pattern for the dispersal of aeciospores of Uromyces psoralen Peck and Puccinia andropogonis Schw. with a maximum during the night when high relative humidity occur red. Furthermore, they found that the aeciospores of Phragmidium speciosum (Fr.) Cooke did not disperse according to a diurnal pattern. The aeciospores of this fungus were released immediately when it rained, regardless of the time of day. Pa d yet al. (1968, 1969) studied the release of Gymnosporan gium sp. aeciospores and found that for some species most aeciospores were released in the morning between 06.00 and 08.00 or, for some other species, generally in the daytime during dry periods. In the aecia of Gym nosporangium there is a mechanism which keeps them closed during moist weather (P ad v et al. 1968). Experiments conducted in dew chambers indicated that the release of spores occurred immendiately at the end of the dew period regardless of the light conditions (P ad yet al. 1969). The aeciospores of Cronartium species are released according to a diurnal pattern (Powell 1972, Pete rs on 1973). Powell (1972) showed that the aeciospores of G. comandrae Pk. were dispersed mainly in dry weather with the diurnal maximum around noon. Sudden rains may increase the spore density, but during continuous rains only a few spores are released into the Timo Kurkela 79.1 48 air (Powell 1972). The rhythm of dispersal of the aeciospores of C. comandrae is very similar to the one observed in the present study for M. pinitorqua. Uredospores. Dispersal of rust uredospores has been investigated much more than that of aeciospores. This is mainly due to the fact that the rusts of cereals are dispersed specifically by uredospores. In general, uredo spores have been found to disperse according to a diurnal rhythm with the maximum spore density shortly after noon (Hirst 1953, Sree r a mulu 1959, Pady et al. 1965, Kramer and Pady 1966). The uredospore dispersal of Melampsora appears to follow the same diurnal rhythm as other rust species. Pady (1971 b) reported that in greenhouse experiments the uredospores of Melampsora euphorbiae (Schub.) Cast, and M. lini (Pers.) Lev. were more often released during daylight hours. In these experiments the spore density usually had been at a maximum at noon or slightly before noon. Tar i s (1966, 1968) studied the uredospore dispersal of Melampsora species on poplars grown in a nursery. The uredospore density in the air reached maximum in the afternoon. Few spores were dispersed if the temperature was below 10 °C, relative humidity above 80 % or wind velocity less than 1 m/sec. A rain which occurred during the study period increased the spore density markedly. Tar is (1966) considered this to be due to the mechanical effect of the rain and wind in releasing the spores. Factors affecting diurnal periodicity of spore dispersal The diurnal periodicity of spore release may be a result of one or more weather factors. Several weather factors, including light, total radiation, temperature, relative humidity of the air, dew and wind, vary according to a diurnal periodicity. The rainfall does not usually follow a diurnal pattern in Finnish conditions. Since all weather factors are dependent on one another in one way or the other, it is very difficult on the basis of field observations to determine whether one or several factors crucially influence the diurnal periodicity of release and dispersal of the spores. Several scientists have tried to investigate this problem in different conditions ranging from field condi tions to microenvironments created in carefully controlled laboratories. The factors controlling periodicity vary according to the species of fungus. Temperature seems to be positively correlated with spore formation (J arv i s 1962 a, Smith 1966, Cole and Fernandes 1970, Hamm ell and Manners 1971), at least when the temperature fluctuates mainly below optimum. For many fungi with dry spores the optimum temperature for spore formation is probably about 20 °C, perhaps Epiphytology of Melampsora Rusts of Scots Pine and Aspen. 79.i 49 7 16568 73 even slightly above. On the other hand, the critical temperature above optimum which completely inhibits spore formation may be rather high (e.g. 27 °C for Alternaria solani, Wagg on e r and Horsfall 1969). Wind (Z obe r i 1961, Smith 1966, Hammett and Manners 1971) and raindrops (collison with leaves) (Davies 1959, Gregory et ai. 1959, Hirst 1961, Bock 1962, J ar v i s 1962 b, H irst and S t e d ma n 1963, Hammett and Manners 1971) are forces releasing the spores. Diurnally varying light often stimulates formation or release of spores (Y arw oo d 1936, Smi t h 1966, Co ] e and F ernandes 1970). Humidity may enhance formation of spores (J arvis 1962 a) for some fungi, but on the other hand, it may slow down their release (Z o b e r i 1961, Smith 1966, Hamm ell and Manners 1971, Powell 1972). A rapid increase in the density of airborne dry spores is usually caused by the initiation of rain (Sreera mu 1 u 1962, Tar i s 1966, Mills 1967, Hammett and Malln er s 1971). With the continuing rain the air is rapidly washed free of spores (Hirst 1953, L u d 1 a m 1967, G h a m b erl ai n 1967). Structures of the mycelia which form the spores may be destroyed by the rain, causing the spore density to remain low for some time after the rain (Y arw oo d 1937, Sreer amu 1 u 1964, Wagg on e r and Horsfall 1969). Limitations in identifying the spores of Melampsora species Literature on the morphology of spores The rusts of aspen leaves are collectively known as Melampsora populnea (Pers.) Karst., which can be subdivided into several races or species accord ing to the host on which the aecial state occurs (cf. L i r o 1908, Hy 1 an der et al. 1953). These fungi cannot be distinguished by morphological characteristics. The aecial states of the following aspen rusts have been found in Finland (H ylan d e ret al. 1953): Melam.psora larici-tremulae Kleb, on Larix, M. viagnusiana Wagner on Chelidonium and Corydalis, M. pinitorqua Rostr. on Pinns, M. rostrupii Wagner on Mercurialis. Obviously, one has to be critical in considering the causal agents of pine twisting rust, M. pinitorqua, and the needle rust of larch, M. larici-tremulae, as different species. At the time, the separation of the two species was done on the basis of results obtained from inoculation experiments (Rostrup 1884, Klebahn 1897 a, b, 1899, Liro 1906), According to some Timo Kurkela 79. i 50 studies (L on g o et ai. 1970), M. pinitorqua also can infect larch. The rusts of pine and larch can probably occur on aspen leaves as mixed populations. Thus, using the same telial material, it is possible to get aecia to form re gardless of which aecial host is used. On the other hand, the aecia of Me lampsora which occur on larch may belong to species with aspen as alternate host or to species in which the uredial and telial states occur on different species of Salix. The name M. larici Hartig (cf. Gäum an n 1959) has been used as the collective name for these larch rusts. According to Zi 11 e r (1959), the lateral walls of the aeciospores of aspen rust generally are ex panded inward, whereas the walls of the aeciospores of rusts on Salix generally are expanded in the other apex. This special feature of the aeciospore walls has not been studied systematically on the aspen rusts occurring in Finland. The aeciospores of Melampsora can be distinguished from the uredospores on the basis of differences in their surface structure. The surface of the aeciospores is finely verruculose and the uredospores have fairly large spines about 2 fi apart (cf. Gäumann 1959, Wilson and Henderson 1966). This is particularly clear on scanning electron micrographs (A rt ha u d 1972). According to the literature, the aecio- and uredospores of aspen rusts are of the same size (cf. Gäumann 1959). For all these rusts the uredospores have been reported to be somewhat more oblong than the aeciospores. The size of the aeciospores has been reported as 13—20 /.« x 12—17 fi and of the uredospores, 15—27 /( X 10—18 /<. There are very few descriptions of the x'ust basidiospores in the literature, including the species of Melampsora. This is apparently due to the minute differences between them. According to Klingström (1963), the basidiospores of M. pinitorqua are round and measure s—B /« in diameter. The figures compiled in Gäu ma n n's (1959) book show basidiospores of Puccinia and Uro Figure 21. Melampsora pinitorqua basidio spores which have been released naturally and deposited on a microscope slide. Some of the spores have an emerging germ tube, x 450. 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen 51 myces rusts as allantoic! in clear contrast to the round ones of Melampsora. Some species of rust (e.g. M e lamp sorid ili m betulinum (Pers.) Kleb.) may have basidiospores of the same size and shape as Melampsora, while the basidio spores of e.g. Thekopsora areolata (Fr.) Magn. are clearly smaller, about 3 //• (G äum an n 1959). The basidiospores of M elampsoridium betulium (Sappin-Trouff y 1896) and many species of Cronartium (H ir t 1935, Ka i s 1963, Kr e bill 1972) may form secondary sporidia during germination. There do not appear to be any such reports on Melampsora. in the literature. Figure 20 shows basidiospores of Melampsora deposited on glass. Some already have germinated during a release period of one half hour. Measurements of spores In order to achieve more accurate identification of spores in examinations of spore trap material, the size distribution of some spore samples of Me lampsora were measured. Aeciospore from the following species were meas ured: M. pinitorqua on Pinus sylvestris L., M.larici-tremulae on Larix sibirica Lebed., and M. rostrupii on Mercurialis perennis L. For measurements of uredospores, samples representing M. pinitorqua were collected from aspen suckers in a pine sapling stand where twisting rust had occurred abundantly during the same growing season and where hosts for other aecial states were not found in the immediate vicinity. The samples of M . larici-tremulae were made on fresh specimens. At least 200 spores per sample of both aecio- and uredospores were measured. The basidiospores of M. pinitorqua were obtained in the laboratory from germinating telia depositing their spores directly on microscope slides. The inoculation of pine transplants were made with the same telial material. Five hundred basidiospores were measured. The optics used were x 400. The results of the spore measurements are presented in Table 5. The spore size distributions of the studied species of Melampsora were almost identical. Consequently, size measurements are not suitable for identifying individual species. The results corroborate data in the literature, even though the aeciospores of different species appear to be somewhat more rounded and the uredospores somewhat more elongated compared with previous reports. The average diameter of the basidiospores was 7—7.5 a with extremes of 5.5 and 9.5 //. When fresh, the basidiospores were yellow but when stored at room temperature this color was lost in about a month. In connection with the measurements, the wall thickness was also observed in order to determine whether this characteristic, reported bv Zi 11 e r (1959), was suitable for distinguishing the spores of aspen and Salix rusts from each other. The observations indicated that the differences in wall thickness varied, depending on the position of the spore. Consequently, this 52 Timo Kurkela 79.4 Table 5. Reults of measurements of aecio-, uredo-, and basidiospores of some Melam psora species. Hilst species Spore form Dimension !» 11) 11 12 13 14 15 l(i Size class ./; 17 18 19 % frequency 20 21 22 23 24 25 20 27 28 Total M. pinitorqua J a Length 4.0 9.0 9.5 11.0 17.0 18.5 18.0 7.0 5.0 0.5 0.5 100 M. larici-tremulae 1 » 0.5 0.5 1.0 1.5 2.5 9.5 11.(1 21.0 15.5 18.0 11.5 4.0 2.0 1.0 0.5 100 M. rostrupii î >> 0.5 0.5 5.5 3.0 7.0 23.0 24.0 21.0 11.5 1.5 1.0 1.0 0.5 100 M. pinitorqua ■ Width 0.5 4.0 10.5 9.5 12.5 19.0 18.0 18.0 6.0 1.0 0.5 100 M. larici-tremulae 1 » 1.0 '-'.(I 4.5 15.0 19.0 19.0 15.5 10.5 5.5 5.5 1.5 1.0 100 M. rostrupii 1 » 1.0 8.0 15.5 21.5 20.5 16.0 11.0 3.5 1.5 1.0 0.5 100 M. pinitorqua 1 ! 11 Length 0.5 3.5 3.0 10.1 20.1 20.6 19.1 10.1 7.5 2.1) 1.0 2.0 0.5 100 >> » II » 0.9 1.0 2. s 10.3 15.1 16.4 22.5 13.0 8.0 5.6 1.9 1.4 0.5 100 M. larici-tremulae II » 0.'.) 1.4 6.4 13.3 17.0 24.8 20.6 10.6 1.4 1.8 0.9 0.9 100 •) » 11 » 0.4 1.7 8.0 17.2 18.5 19.3 16.4 11.8 4.6 1.3 0.4 0.4 100 M .pinitorqua II Width 2.0 5.:i 17.4 31.9 31.8 9.7 1.0 100 •> ■> 11 » 1.0 3.9 13.0 14.0 18.3 17.9 19.3 10.2 1.4 1.0 100 M. larici-tremulae II » O.Ii 6.5 9.3 15.8 22.3 18.8 15.4 6.5 2.3 100 •> » II » 1.1 11.5 15.1 21.5 21.6 17.0 '.1.11 1.4 0.9 100 Size class, p 5.Л Ii. II !>..3 7.0 7.5 8.0 8.5 9.0 9.5 % frequency .1/. pinitorqua IV' Diam. 1.4 5. 4 14.0 21.0 25.4 17.2 8.4 5.0 1.0 100 a ) I = aeciospores 11 ) 11 -uredospores c ) IV == basidiospores 79.1 Epiphytology of Melampsora Rusts of Scots Pine and Aspen 53 characteristic can be used only when examining a large number of spores of the same origin (e.g. when identifying aecia developed on the needles of larch). Characteristics which determine rust incidence in pine stands The incidence of rust on the aspen leaves, the germination capacity of the telia, and the weather conditions influencing the pathogen are, of course, the most important properties controlling the infection of the pine shoots in a stand; but the infection also is partly dependent on the structure of the pine sapling stand and the resistance of the pines. Klingström (1969) and v. Weissenberg (1973) isolated from shoots of Pinus silvestris L. and P. taeda L. some substances that inhibited germination of basidiospores of M . pinitorqua and Cronartium fusiforme Hedge & Hunt ex Cumm. These substances may, in one way or the other, be related to rust resistance. According to many investigators (Eklundh-Ehrenberg 1963, Schiitt 1964, Illy 1966, Kardell 1966, Klingström 1969), the tallest or most vigorously growing saplings commonly have been more intensively infected by the rust. Syl v e n (1917) and Klingström (1963) observed that the rust occurred more frequently on the terminal leader than on the shoots of the current whorl. This was also observed in the present study. Also, Karu (1937) found that smaller saplings, which often are protected by grass or the branches or larger saplings, were less commonly infected than larger saplings. According to Nab at o v (1968), a dense cover of grass will protect the pine saplings from infection by basidiospores of ill. pinitorqua. The uneven soil surface and the ground cover absorb airbone spores, resulting in a more rapid reduction of spore density with increased distance to the source of inoculum among ground cover than above it (W aggo n e r 1965). It is, of course, natural that there may even be considerable genetic variation in resistance; and, on the other hand, the terminal leaders are clearly more susceptible to the rust than are the leaders of the branches. The more frequent infection of larger saplings may be partly due to a more favorable environment for trapping infective spores. Interaction of pine and rust The capacity of one aecium of twisting rust to produce spores appears to decrease with increasing density of aecia on the shoot. In studying inocu lated seedlings of wheat and oats, it has been noted that where large num bers of competing mycelia are crowded in a leaf, the pustules formed are Timo Kurkela 54 79.1 minute and produce few spores (Allen 1923 a). Allen (1923 a) also found that a sparse infection causes greater damage to the host than does the same number of basidiospores infecting the host in closer proximity to each other. The damage caused by the twisting rust is not directly dependent on the number of lesions of infection, since even one aecium alone may be lethal if the infection occurs in an early enough stage of growth. The later the infection occurs, the larger the number of primordial aecia that do not complete their development. When the growth of the shoot is completed, the tissue of the shoot surface appears to grow strong enough not to allow the late-developing aecia to burst open. Moriondo (1954) has found such unopened aecia. In both the present study and in the experiments by Long o and Nald i n i (L on g o et ai. 1970) the development of aecia took 11—14 days from the time of inoculation. Regler (1957) and Moriondo (1961) reported that the development of the aecia took 16 days. Rust on aspen leaves The development of aspen rust in the Finnish conditions seems to start when the aeciospores infect the aspen leaves. The overwintering of the uredial state as mycelium may sometimes, however, be possible (K 1 e b a h n 1938, Kujala 1950, Regler 1957, Moriondo 1961, G e et ai. 1964). Uredospores may also overwinter in suitable conditions (C h i b a and Zinno 1960). The factors influencing the amount of aspen rust are the number of aeciospores infecting the aspen, conditions of rain and temperature when these spores are dispersed and, in addition, the weather in July—August when the uredial state reproduces. The fructification period of the uredial state was found to be 10—14 days when the inoculation was done with aeciospores (cf. Hartig 1885). The same experiment has not been done with uredospores. In the experiments done by Toole (1967) the develop ment of uredia took four days from the time the leaves of Populus deltoides Marsh, were inoculated with uredospores of Melampsora medusae Thiim. In nature the deposition of a uredospore on a susceptible surface does not invariably result in infection, but often several days may pass and many spores may die before the weather is suitable for infection. Therefore, the reproduction of the disease in nature is much slower than expected on the basis of the fructification or generation cycle. The summers of 1966 and 1967 with their regularly occurring rains were relatively favorable for the increase of aspen rust. The summer of 1968 was unfavorable for rust development. On the experimental area of Ikaalinen the number of aecia was small, and rainless weather dominated when these Epiphytology of Melampsora Rusts of Scots Pine and Aspen 79.i 55 spores and the uredospores were dispersed. The increase in the rust popula tion was much slower than during the previous summers. When the increase is measured by the changes in the total number of uredia, it seems most likely that the progress of the epiphytotic is relatively faster at the beginning of the growing season than at the end. During the progress of the epiphytotic, an ever-increasing portion of the uredia lose their spore-producing capacity when the nutrients of the substrates are becoming utilized or due to secondary fungi or bacteria. When the growing season is suitable for development of Cladosporium, this fungus may rapidly infect the newly-developed uredia, apparently inhibiting their spore-producing capac ity; and consequently, the number of spore-producing uredia remains small (Kurkela 1973b). Rainy weather permanently reduces the germination of uredospores formed by the uredia, apparently due to secondary infections (Bier 1965). The same kind of a situation is also observed with Cronartium comandrae (Powell 1971), in which case the main secondary colonizing organism in rust galls was Cladosporium gallicola Sutton (Sutton 1973). Zadoks (1961) also reports that cereal rust epiphytotics in rainy seasons usually are not very severe. The reproductive capacity of the fungus is considerably reduced if the mycelium in the tissue of the host cannot expand and form new uredia without new uredial infection (cf. Manners 1971). Since the network of vascular bundles, which prevent expansion of rust mycelia, is rather dense, it is hardly possible that one infection could result in several uredia. Consequently, the emergence of secondary uredia around the primary uredium probably requires new infections. This view is sup ported by the observation that the secondary uredia always occur completely at random around the primary uredium, and not in concentric rings around it, which would be the case if the expansion of the mycelium was not limited (Allen 1923 b, 1928). Possibilities tor control of pine twisting rust The obtained results indicate that the main factors influencing the incidence of pine twisting rust are: 1) the number of overwintering telia on aspen leaves from the previous year, 2) precipitation and duration of rain fall during height growth of pine and 3) the timing of the telial germination activity during pine growth. When these conditions are favorable for rust development, the pines are infected. Eradication of the aspen, the host of the uredial and aecial states of M. pinitorqua, from the pine sapling stands has been considered the most reliable means of controlling pine twisting rust (H art i g 1885, Lies e 1923, Timo Kurkela 79.) 56 Böhll e r 1952). Nowadays the eradication of the aspen is achieved best with chemical methods (Rennerfelt 1954, Barring 1965, Rum mukainen 1969 a, b). The chemical control of rust on aspen suckers probably is technically feasible today(cf. Aer t s 1963, Froi 1 a n d and L i 111 efi e 1 d 1972), but for economic reasons, it cannot be done; and, on the other hand, control of the aspen rust would promote growth of the suckers which would hinder the growth of pine saplings. Assuming that the aspen, at least to some extent, has the same beneficial effect on the soil as the birch (cf. Mikola 1954) and keeping in mind the value of aspen from the standpoint of game management, the aspen should not be totally eradicated, but its growth should be suitably limited. The growth inhibition caused by the rust (cf. FAO 1958, Lilja 1973) may be considered an advantage. This advantage offered by the rust could be used by spreading in aspen sucker stands a rust which does not have pine as its aecial host. The most suitable rust for this purpose would be the larch rust, M. larici-tremulae. It would remain on the area if some larch were planted as mixture in the pine stand. The spread of larch rust to the aspen leaves may already begin about half a month earlier than M. pinitorqua (p. 42). This time difference for the start of the epiphytotic may be crucial in establishing the desired proportions of the two rusts in the pathogen population. Assuming that the spore-producing capacity per pustule of each species is the same and that formation of new pustules is not possible in previously infected tissue, the proportion of the two rust species will remain as it was when the aeciospores of the later-arriving rust caused its primary infection. At the end of this rust epiphytotic, when new susceptible leaf tissue is no longer formed, the amount of infected tissue will crucially limit the development of new pustules. If, for example, 50 % of the leaf surface is infected, which may be possible at the end of July if the epidemic started at the beginning of June, only half of the spores deposited on the leaf surface can cause infection. If the number of aeciospores of the two rust species is the same when causing the primary infection and the one rust starts to spread one month earlier than the other and if the amount of rust increases tenfold in one month, the ratio between the two species is 10 : 1. The maxi mum number of telial pustules (all palisade parenchyma tissue is infected) on an aspen leaf is about 200 pustules/sq.cm, of which pustules of twisting rust, considering a mixed population of M. larici-tremulae and M . pinitorqua, would be only slightly more than 20 pustules/sq.cm. Since during years of abundant rust, the number of telial pustules of M. pinitorqua was on an average not more than 120—150 pustules/sq.cm, the number of telia of twisting rust would be even less than 20 pustules/sq.cm. The drawback of this rust control measure, i.e. using a mixed rust population, is that its 79.4 Epiphytology of Melampsora Rusts of Scots Pine and Aspen 57 8 10568 —73 effectiveness cannot be measured unless the quantitative identification of the different rusts is possible. So far, no reliable method has been found for this purpose. The determination of the amount of rust in the field does not reveal the effectiveness of the method. The rust can spread over experimental plots located close to each other. Plots located far a way from each other cannot be compared since the differences in the local conditions may greatly influence the amount of rust and the development rate of the epiphytotic. There are a few investigations on the negative effect of a primary infection on the secondary infection. A strong local infection may reduce the intensity of a later, secondary infection by the same species (Uromyces pJiaseoli) (Y arw oo d 1954). Inoculation with avirulent races of the rust may later reduce the intensity of a virulent race of the same species (M. Uni field 1967). Two different pathogenic species may prevent each other's development on the host plant (Johnston and Huffman 1958) in the same way as the growth of a non-pathogenic species on the leaves of its host (Y arw oo d 1956). Another rust control method may be worth developing: the spread of a secondary parasite or saprophyte in the rustsusceptible aspen sucker or pine sapling stand. Bier (1965) found that some common saprophytes living on the leaves of black cottonwood reduced the rust on them. Infection of the uredial pustules of aspen rust by Ramularia (Magnani 1971), and the Cladosporium fungi (Kurkela 1973 b) may considerably reduce the dispersal of uredospores. In the Soviet Union Vasiljev et al. (1970) obtained promising results in controlling twisting rust with preparations of some bacteria. CONCLUSIONS The conclusions subsequently presented are based mainly on results obtained from the present study but also on results published elsewhere by the author (Kurkela 1973 a, b). 1 . The formation of basidiospores occurs only under the influence of rain. The dew does not provide enough moisture for basidiospore formation, and the duration of dew during the night is not long enough. The dispersal of basidiospores commonly begins 4—(i hours after the rain starts. Air humidity does not seem to play an important role in the formation and dispersal of spores if there is free water in the leaf litter. A reduction in air humidity also causes the leaf litter to dry and spore production to stop, resulting in a rapid decrease in the number of airborne spores. 2. Increased air temperature increases the formation of spores and results in early commencement of spore release and larger spore density in the air during maximum dispersal in periods of high temperature. The for mation and thus, also the dispersal of the basidiospores occurs over a wide temperature range +5 to +25 °C. The spore formation is at a maximum between 12—22 °C. 3. Wind does not have a crucial influence on the number of airborne spores. The spores are dispersed by the wind, resulting in their deposition on pine shoots according to wind direction. 4. The dispersal of basidiospores may occur in the spring, during May and June, in 2—4 separate periods of rain after which airborne spores are not observed regardless of favorable weather conditions. 5. The formation of aecia on the pine shoots or larch needles is a result of infection caused by basidiospores dispersed during rainy weather. A long rainy period leads to more severe infection. 6. The aecia are formed on the pine shoots within 10 —14 days after infection. 7. The infection of the shoots can occur only when the surface of the shoots has been exposed between the fascicle scales. The shoots become resistant when shoot elongation has ceased. In greenhouse conditions with high relative air humidity needles also may be infected. 79.i Epiphytology of Melampsora Rusts of Scots Pine and Aspen 59 8. The aeciospores are dispersed when the aeoia are mature, beginning at the end of June and continuing through mid-July. 9. There is a clear diurnal rhythm in the dispersal of aeciospores, which most likely is a joint result of all the weather factors following a diurnal rhythm (temperature, relative air humidity, dew, wind, radiation etc.). 10. The formation of aeciospores appears to be at a maximum during high temperature. A high relative air humidity may slow down the release of aeciospores. 11. The number of airborne aeciospores begins to increase from its nightly minimum in the morning at about 06.00, reaching a maximum in the morning or at noon during dry weather. The drop to a minimum is slower than the increase to maximum. 12. A beginning rain is in strong positive correlation with airborne spore density. A maximum may be reached any time of the day as the result of a sudden strong shower, e.g. a thundershower, since it effectively releases spores. 13. As a result of infection caused by the aeciospores on the lower surface of aspen leaves, the uredia develop within B—l 48 —14 days. The uredospores cause the multiplication of the rust on the aspen leaves with an initial logarithmic increase. When the dispersal of the aeciospores begins, most of the aspen leaves have already grown to full size. 14. The number of uredia reaches a maximum at the end of August when there may be 40—50 uredia/sq.cm during a year of abundant rust. The telia are developed in August — September and exceed the number of uredia by about 3 times. 15. The production of spores in the uredia may often be reduced by hyperparasites in the uredia or by secondary parasites spreading into the tissue through the uredia. 16. The veins of the leaf inhibit the growth of the rust mycelium in the leaf. The mycelium often stops at the veins. Due to the small size of the areas delineated by the veins, several uredia cannot develop from one in fection. 17. The rust mycelium in the leaf tissue is intercellular. Throughout the mycelium are mother cells of haustoria. From the mother cell thin hyphae penetrate the walls of the host cells, and haustoria are formed in the tips of the hyphae. 18. The dispersal of uredospores follows the same pattern as that of the aeciospores. The maximum for airborne uredospores is at the end of August. 19. The damage caused to the pine shoots by the rust infection depends on its severity and time of occurrence. An infection occurring late in the shoot Timo Kurkela 79. i 60 expansion period usually causes only a rapidly healing scar, while an early infection causes the shoot to bend severely and finally die. 20. The amount of both aspen rust and pine twisting rust varies greatly from year to year. Dry weather unfavorable to rust development during any phase of the cycle may endanger the annual cycle. The M dam psora fungus is most sensitive to damage in its telial or basidial stage. If in the spring rain does not occur at a suitable time, basidiospores may not be formed. The basidiospores cannot cause infection unless the host plant is in the proper phase of growth or if the weather rapidly becomes dry when the basidio spores have been formed. Another sensitive phase occurs when the aeeio spores are dispersed to the aspen leaves. If it is continuously dry at this time, the aspen leaves are not infected and the cycle is interrupted. SUMMARY The dispersal of different spores of Melampsora pinitorqua and M. larici tremulae (causal agents of pine twisting rust and larch needle rust) was studied using mainly the Hirst spore trap. The growth of pine shoots and development of rust on them was followed by daily observations. Pine shoots also were inoculated artificially. The development of rust on the aspen leaves was followed by counting the number of pustules on leaf samples which were collected weekly. Also, the growth of aspen shoots and leaves was measured daily. The basidiospores of Melampsora dispersed in the spring during May and June. Dispersal took place under moist weather conditions, starting 4 —6 hours after the beginning of a rain, and reaching maximum after some ten hours of rain. When the rainy weather continued for a longer time, infection of pine shoots took place. Those shoots which had terminated their growth were resistant to the rust. The development of aecia on the pine shoots took place within 10 —14 days. The aeciospores dispersed in the period June—July, and thereafter the uredial state was formed on the leaves of aspen. The numbers of aeciospores and uredospores in the air usually reached maximum around noon. These spores are both of a type which are distributed dry. High temperature stimulated development of the rust and spore formation. Wind gusts and rain showers occurring during a warm spell may suddenly swell the numbers of these spores at an extremely high rate. 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A synthetic approach to stepwise regression analysis. Comment. Phys.-Math. 34, 91 —132. Vasil j e v, O. A., D. A. Orec h ov, and M. S. Shkl j a r. 1970. (Concerning the applications of biological substances for pine protection against pine rust induced by Melampsora pinitorqua, (A. Braun) Rostr.). Mikol. i Fitopatol. 4, 242—246. \V aggo n e r, P. E. 1965. Microclimate and plant disease. Ann. Rev. Phytopath. 3, 103—126 Timo Kurkela 79.1 68 Waggoner, P. E. and .1. (1. Horsf a 1 1. 1969. Epidem. A simulator ofplant disease, written for a computer. Bull. Conn. Agr. Exp. Sta., New Haven, 698. 80 pp. Wei ssenberg, K. v. 1973. Indirect selection for resistance to fusiform rust in loblolly pine. Acta For. Fenn. 134. 46 pp. Wils on, M. and D. M. Hende r s o n. 1966. British rust fungi. 384 pp. Cam bridge Univ. Press, Cambridge. VV o od, F. A. and R. A. Schm i d t. 1966. A spore; trap for studying spore release from basidiocarps. Phytopathology 56, 50—52. Y a r woo d, C. E. 1936. The diurnal cycle of the powdery mildew Erysiphe polygoni. ,T. Agr. Res. 52, 645 —657. i) 1937. The relation of light to the diurnal cycle of sporulation of certain downy mildews. J. Agr. Res. 54, 365—373. » 1954. Mechanism of acquired immunity to a plant rust. Proe. Xatl. Acad. Sei. U.S.A. 40, 374—377. —» 1956. Cross protection with two rust fungi. Phytopathology 46, 540—544. 7. ad o ks, .T. C. 1961. Yellow rust on wheat, studies in epidemiology and physiologic specialization. Tijdschr. Pl.-ziekten 67, 69 —256. Z i 11e r, W. ('!. 1959. Studies of western tree rusts. V. The rusts of hemlock and fir caused by Melampsora epitea. Can. J. Bot. 37. 109—119. Zoberi. M. H. 1961 Take-off of mould spores in relation to wind speed and humidity. Ann. Bot., New Ser. 25, 53—64. MÄNNYN YE RSO RUOSTEEN JA HAAVAN RUOSTEEN EPIFYTOLOGIA Melampsora pinitorqua on männyn versoruosteen aiheuttaja. M. larici-tremulae aiheuttaa lehtikuusen neulasruosteen. Mainituilla isäntäkasveilla nämä ruostesienet esiintyvät helmi-itiöasteisina. Molempien kesä- ja talvi-itiöaste kehittyy haavan leh dillä. M. pinitorquan ja M. larici-tremulaen eri itiömuotojen leviämistä ilmassa tutkit tiin käyttäen pääasiassa Hirst-itiöpyydystä. Männyn versojen kasvua ja ruosteen kehi tystä niillä seurattiin päivittäisin havainnoin. Ruosteen kehitykseensä vaatiman ajan määrittämiseksi tehtiin myös keinollisia saastutuksia. Ruosteen kehitystä haavan lehdillä seurattiin viikon väliajoin tehdyin havainnoin sekä mittaamalla haavan ver sojen ja lehtien kasvua päivittäin. Ruosteiden eri asteiden kehityksessä ja runsaudessa esiintynyttä vaihtelua verrattiin eri säätekijäin vaihteluihin. Melampsoran basidiosporit levisivät keväällä touko —kesäkuussa. Leviäminen tapahtui kostealla säällä alkaen 4—6 tunnin kuluttua sateen alkamisesta ja saavutti maksiminsa n. 10 tunnin kuluttua. Kostean sään jatkuessa edelleen yhtäjaksoisesti tapahtui männynversojen saastuminen. Kasvunsa päättäneet versot olivat ruosteen kestäviä. Helmi-itiöpesäkkeiden kehitys männynversoissa tapahtui 10—14 päivän kuluessa. Helmi-itiöt levisivät kesä —heinäkuussa, minkä seurauksena tapahtui kesä itiöasteen muodostuminen haavan lehdille. Helmi- ja kesäitiöiden määrä ilmassa oli yleensä runsaimmillaan keskipäivän aikaan. Nämä molemmat ovat ns. kuivana leviä viä itiöitä. Korkea lämpötila edisti ruosteen kehitystä ja itiöiden muodostusta. Läm pimällä säällä sattuneet tuulenpuuskat ja sadekuurot voivat äkillisesti nostaa näiden itiöiden määrät ilmassa erittäin suuriksi. Sekä männyn versoruosteen että haavan ruosteen runsaus vaihteli eri vuosina hyvin paljon lähinnä sääsuhteista johtuen. KENTTÄVARASTOINNIN SUORITUSTAVAN VAIKUTUS KUUSEN TAIMIEN ALKUKEHITYKSEEN OLAVI HUURI SUMMARY: THE EFFECT OF FIELD STORAGE METHODS ON INITIAL DEVELOPMENT OF PLANTED SPRUCE HELSINKI 1973 ISBN 9 51-4 0-0083-8 Helsinki 1973. Valtion painatuskeskus ALKULAUSE Pyrittäessä selvittämään männyn ja kuusen istutukseen liittyvien eri työ vaiheiden merkitystä istutuksen kokonaistulokselle tahdottiin Metsäntutki muslaitoksen metsänhoidon osaston 1960-luvulla aloittamissa koesarjoissa tutkia myös taimien kenttävarastoinnin erilaisten suoritustapavaihtoehtojen vaikutusta taimien alkukehitykseen maastossa. Siinä tarkoituksessa perus tettiin männyn ja kuusen taimien kenttävarastointia koskevia esikokeita Hartolaan vuosina 1964—1966. Tässä julkaisussa selostetaan kokeiden tulok sia kuusentaimien varastoinnin osalta. Työhön ovat kirjoittajan ohella osallistuneet rouva Aili Heikkonen ja metsätyömies Esa Sarikka viikosta toiseen toistuneiden istutusten suorittajina, vaimoni Leena Huuri kokeiden mittaajana ja aineiston käsittelijänä sekä herra Olli Virta tulosten laskijana, testaajana sekä tämän julkaisun kuvien piirtäjänä. Neiti Riitta Kantola on kärsiväl lisesti ja huolellisesti suorittanut käsikirjoituksen puhtaaksikirjoitustyön. Metsänhoitaja Kullervo Etholen on suomentanut venäjänkielisen lähdekirjallisuuden ja tohtori Kim. v. Weissenberg on kääntänyt englanniksi julkaisun lyhennelmän ja kuvatekstit. Tohtori Matti Lei kolan ohjaus ja kritiikki on erittäin hyödyllisenä ollut käytettävissä julkaisun koko kirjoitusvaiheen ajan. Hänen ohellaan ovat käsikirjoitukseen tutustuneet professorit Olavi Hui kari, Risto Sarvas ja Paavo Yli-Vakkuri, tohtori Veikko Hintikka sekä maisteri Ukko Rummukainen varteenotettuja parannusehdotuksia tehden. Myös monet käytännön metsän viljely työtä johtavat metsäammattimie het ovat tutkimussarjan eri työvaiheissa antaneet kirjoittajalle arvokasta apua niin uusia ideoita kirvoittavina keskustelijoina kuin rohkaisijoina ja kriitikkoinakin sekä myös käytännön tukea antaen. Heistä mainittakoon tässä yhteydessä ennen kaikkea metsäneuvos Oiva Lyytinen, metsätek nikko Toivo Martikainen ja metsänhoitaja Mauno Uusitalo. Suomen Luonnonvarani Tutkimussäätiö ja Tiuran Säätiö ovat tukeneet taloudellisesti tutkimusten sarjaa, josta nyt julkaistava tutkielma muo dostaa yhden osan. Kirjoittaja tahtoo kohdistaa parhaan kiitoksensa kaikille yllämainituille työtovereilleen ja auttajilleen. Helsingissä lokakuussa 1973 Oton Huuri SISÄLLYSLUETTELO Sivu 1. Johdanto 5 2. Tutkimusaineisto ja -menetelmä 8 21. Käytetyt taimet 8 22. Varastot ja varastointiajat 8 23. Testisarjat ja niiden perustaminen 11 24. Mittaukset ja havainnot 14 25. Tulosten laskenta 15 3. Tutkimuksen tulokset 16 31. Varastoinnin suoritustavan vaikutus taimien eloonjäämiseen ja kuntoon 16 311. Varastointi talouskellarissa 16 312. Varastointi valeistutuksessa 19 313. Varastointi ojavedessä 21 314. Varastointi kaivovedessä 24 315. Varastointi taimipenkissä 25 316. Varastojen vertailua 28 32. Varastoinnin suoritustavan vaikutus taimien kokonaispituuteen ja vuotui seen pituuskasvuun 28 4. Tulosten tarkastelua 35 5. Tutkimuksen päätulokset 37 6. Lähdeluettelo 38 7. Summary 40 1. JOHDANTO 'Taimia tai vesoja ei saa niiden noston jälkeen jättää pitkäksi aikaa maassa virumaan, sillä silloin ne kadottavat ilman, tuulen ja auringon vaiku tuksesta helposti nesteensä. Parasta olisi, jos ne voitaisiin istuttaa samana päivänä, jona ne on nostettukin. Mutta jos ne pitää kuljettaa kauemmaksi tai niitä ei voida heti istuttaa ja ne joutuvat olemaan muutamia päiviä ylhäällä maasta, voidaan ne kietoa olkiin tai sammaliin, tai mikäli on mah dollista upottaa niiden juuret viileään veteen, mikä on erikoiseksi hyödyksi ja estää nesteiden ja kosteuden pakenemisen. Muutamat panevat nostetut vesat yhdeksi yöksi vesikuoppaan, mikä ei ole vahingoksi. Muutamilla puutarhanhoitajilla on myös tapana pystyttää nostetut vesat multaan ja peittää sillä niiden juuret ja sen jälkeen tilaisuuden tullen istuttaa vesat vähin erin' (käännös saksankielestä). Näin esittelee ohjeita taimien varastoinnista varhaisin tunnettu pelkäs tään metsätaloutta esittelevä teos »Sylvicultura oeconomica» (v. Carlo witz 1713) kuudennentoista kapittelinsa 16. pykälässä. Noina aikoina ei taimien varastointi tullut kovin usein kysymykseen istutusten vähäisyyden takia sekä siitä syystä, että tuolloin istutuksiin käytetyt taimet pääasiassa nostettiin luontaisten taimistojen tiheimmistä kohdista juuripaa kuissaan ja siirrettiin harvempiin, täydennystä kaipaaviin taimiston kohtiin viime hetkeen saakka alkuperäisellä kasvupaikallaan kehittyneinä. Paljasjuuristen taimien käytön yleistyessä 1800-luvun jälkipuoliskolla ja myös taimien kuljetusmahdollisuuksien lisääntyessä rautatieverkoston 1850- luvulla tapahtuneen voimakkaan kehityksen mukana (H esm e r 1950) jouduttiin taimia varastoimaan niin taimitarhoilla, kuljetusvälineissä kuin istutuspaikoillakin entistä yleisemmin. Mielenkiintoista on havaita, että tällöin itse taimien suoj aarnistavat pysyivät edelleen jotakuinkin samanlaisina kuin mitkä jo v. Carlowitz oli esittänyt (Cotta ja Berg 1856, Burekhardt 1893, Heyer 1893, Gayer 1898 ja Reuss 1907). Juurten suojana käytettiin yleisesti märkää sammalta ja tavallisimmin suositeltu taimien varastointitapa istutus paikalla oli valeistutus. Mm. Cotta ja Berg (1856) korostavat niiden huolellisen käytön tärkeyttä 'Maasta nostettujen taimien juuret on suojat tava aurinkoa ja tuulta vastaan sammalilla tai muilla sopivilla peiteaineilla. 6 Olavi Huuti 79.r, Kun taimet saapuvat istutuspaikalle eikä niitä heti voida istuttaa, ne 011 välittömästi ja huolellisesti sijoitettava valeistutukseen. Nämä ovat kaksi tärkeätä sääntöä, joita vastaan käytännössä näkee usein rikottavan' (kään nös saksankielestä em. teoksen sivulta 322). Myös meidän oloissamme on valeistutus ollut suositelluin välittö mästi istutuspaikalla suoritettavan varastoinnin muoto (esim. Blom qvist 1898, Paavonen 1915, Hannikainen 1919. Ahola 1930, Borg 1948, Ahola 1949, Kauttu 1965. Lehto ja Simo linna 1966 sekä Ant o 1 a ja Lehto 1969). Useimmat mainituista ohjeiden esittäjistä ovat kuitenkin suositelleet taimien väliaikaista va rastointia myös erilaisissa kellareissa, mikäli niitä on ollut käytettävis sä riittävän lähellä istutuspaikkaa. Taimet on meillä tavallisesti neuvottu valeistuttamaan varjoisaan metsämaastoon kaivettuun ojaan, johon taimi niput asetetaan vieri viereen juuret tiiviisti irtomaalla peittäen. Mikäli kui vuus tai helle uhkaavat taimia, on niput peitettävä esim. kuusenhavuilla. Valeistutusvakoa on myös kasteltava tarpeen mukaan (Paavonen 1915. Hannikainen 1919, Ant o 1 a ja Lehto 1969). Jotta maan kos teus olisi jo itsestään taattu, on sopiva valeistutuspaikka yleisesti etsitty kostealta maaperältä, esim. suon laidalta. Kehitys on johtanut myös siihen, että taimien juuret on ruvettu upottamaan maastossa keväisin helposti löy tyviin vesikuoppiin tai pikku puroihin pelkän veden peittoon. Tästä varas tointitavasta aiheutuvana haittana on kuitenkin esitetty mm. se, että hienot maahiukkaset tällöin huuhtoutuvat veden mukana ja niiden juurille antama suoja vähenee (Yli -Vak k u r i 1961). Taiminippujen avovedessä säilyttämistä on esim. Blekingen läänissä Ruotsissa suositeltu jopa niin hyvänä varastointi tapana, että sen käyttöä on pidetty eräänä selityksenä sikäläisten kuusenistutusten erityisen hyvälle onnistumiselle (S tää 1 1964). Vuodesta 1953 alkaen kuusen taimet on siellä varastoitu heti autokuljetuksen päätyttyä juoksevaan tai seisovaan veteen, jossa niitä on säilytetty jopa kahdeksan viikkoa istutustuloksen hei kentymättä. Suomessa on mm. Yli-Vakkuri käsitellyt tätä kysy mystä (esim. 1961). Hän päätyy kuitenkin suosittelemaan vain lyhytaikaista juurten vedessä pitämistä. Hänen havaintojensa mukaan lyhytaikainen juur ten liottaminen lisää taimien elinvoimaa erityisesti sellaisissa tapauksissa, että ne ovat kärsineet lievästä vesivajauksesta. Tähän käsitykseen on pää tynyt myös Räsänen (1970). Laajimpia tutkimuksia taimien pakkauksesta ja kuljetuksesta sekä niiden erilaisten suoritustapojen vaikutuksista on meillä suorittanut Yli-Vak kuri (1957). Tätä työtä on viime vuosina laajennettu koskemaan myös kentällä tapahtuvaa välivarastointia, mm. valeistutusta sekä kellarivaras tointia (Räsänen ym. 1970 sekä Räsänen 1970). Viimeksimainitut tutkimukset on kuitenkin suoritettu pelkästään männyn taimia käyttäen. Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 7 79.5 Tämän tutkimuksen tarkoituksena on vertailla muutamia kuusen taimien varastointitapoja, jotka olivat yleisesti käytössä Etelä-Suomessa tutkimuk sen suorittamisaikana. Kirjoittajan oma käytännön kokemus sekä neuvotte lut metsänviljelytyötä kentällä ohjaavien ammattimiesten kanssa antoivat varastointitapoj en valinnalle pohjaa. Tutkimuksella pyrittiin selvittämään, miten pitkälle kesään kullakin varastointitavalla voitaisiin siirtää istutuksen ajankohtaa ilman että istutustulos liiaksi huononisi. Kokeet rajoitettiin kos kemaan vain avomaalla kasvatettuja, koulittuja kuusen taimia. Kokeita perustettiin vain yhdelle eteläsuomalaiselle paikkakunnalle, Hartolaan, jossa koesarjoja kuitenkin istutettiin kahden vuoden, 1964 ja 1966, olosuhteissa. Koealueiden maaperä oli kuusenistutuksessa yleisimmin kyseeseen tulevaa ravinnerikasta kangasmaata. 2. TUTKIMUSAINEISTO JA -MENETELMÄ 21. Käytetyt taimet Koska kuusentaimista kokonaan avomaalla kasvatetut, 2A +2A-lajiset taimet (R au 1 o ja Hint tai a 1972) olivat kokeen suorittamisaikana laajassa metsänviljely työssä yleisimmin käytettyjä, kohdistettiin varas tointikokeet pelkästään niihin. Taimet hankittiin vuoden 1964 koetta (koe A) varten eräältä yksityiseltä, lähellä koealuetta sijaitsevalta taimitarhalta ja vuoden 1966 uusintakokeeseen (koe B) Itä-Hämeen piirimetsälautakunnan Hartolassa sijaitsevalta taimitarhalta. Taimet oli kasvatettu paikallisesta siemenestä. Ennen taimien nostoa taimipenkistä rajoitettiin ne arpomalla määräytyneet kohdat, joihin taimet jätettiin toistaiseksi koskemattomina kasvamaan (vrt. sivu 9, varastointitapa 5). Noston jälkeen ennen toisiin käsittelyeriin arpomista taimet pyrittiin valikoimalla saamaan saman kokeen puitteissa pituudeltaan ja tanakkuudeltaan mahdollisimman yhdenmukai siksi. Niistä eroteltiin pois kokonaiserän keskikokoa selvästi pienemmät ja myös suuremmat taimet sekä ulkoasultaan poikkeavat, sairaat ja mekaani sesti vahingoittuneet taimet. Taimipenkissä varastoitujen taimien (5) osalta valinta tehtiin kuitenkin vasta kunkin istutuserän noston jälkeen. Työn kaikkien vaiheiden aikana taimet suojattiin mahdollisimman hyvin häiriö tekijöiltä. Esim. lajittelut suoritettiin aina kellarin kosteudessa. 22. Varastot ja varastointiajat Seuraavia varastoinnin suoritustapoja kokeiltiin: 1. Varastointi talouskellarissa. Taimet sijoitettiin tiheään asen toon kuitenkin niput löyhennettyinä puulaatikkoon, jonka pohja oli peitetty märillä rahkasammalilla. Laatikon reunojen ja taimien väliin sekä muihinkin taimi väleihin tungettiin sammalta. Sammalien kosteutta tarkkailtiin ja niitä kasteltiin aika-ajoin kaivovedellä. Laatikko sijoitettiin tavalliseen maalaistalon talouskellariin, jonka lämpötilaa ja ilman kosteutta seurattiin piirturilla. Lämpötila vaihteli seitsemän ja kahdentoista asteen välillä ja ilman suhteellinen kosteus välillä 85 %—BB %. 2. Varastointi valeistutuksessa. Taimien valeistutusta varten kai vettiin oja syvämultaiseen Pteris-kasvuston peittämään kohtaan yli-ikäisen raudus koivikon varjoon. Taimien juuret peitettiin ojaan paikalta otetulla kuohkealla, run saasti humuksensekaisella moreenimaalla. Taimet jäivät hiukan kaltevaan asentoon 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 9 2 17138—73 Kuva 1. B-kokeen taimia valokuvattuina 4. 7. 1966 vesisam miossa. Taimet ovat olleet 28 vuorokautta kaivoveteen varas toituina. Figure 1. Transplants of experiment B photographed on July 4 1966 immersed in a tub of water. The transplants have been stored in well water for 28 days. suoriin ja tiheisiin riveihin. Valeistutuskohta oli varjoinen, joten taimia ei peitetty. Varastointikohdan multaa kasteltiin kaivovedellä silloin tällöin kuivimpina aikoina. 3. Varastointi ojavedessä. Taimet painettiin löyhennetyissä nipuissa juurenniskaa myöten veden peittoon istutusalueen lähellä hitaasti virtaavan pie nen joen rantaan. Uppoamisen estämiseksi niput kiinnitettiin puukehykseen, jonka varassa ne saattoivat kellua oikeassa syvyydessä, vaikka vesi varastoinnin aikana odottamatta olisi noussutkin. Veden lämpötilaa ei mitattu. Hitaasti virtaava vesi kuljetti mukanaan hiukan mutaa, jota varastoinnin aikana tarttui myös taimien juu riin. Myös veden pieneliöstö pääsi vapaasti vaikuttamaan taiminippujen juuristoihin. Taimet olivat rantapensaikon varjossa, mutta muuten peittämättöminä. 4. Varastointi kaivovedessä. Löyhennetyt taiminiput seisoivat kai vovedellä täytetyssä matalassa sammiossa juurenniskaa myöten veden peittäminä (kuva 1). Sammion vesi vaihdettiin kerran viikossa. Sammio oli sijoitettu koivikon varjostamaan paikkaan. Muulla tavoin taimia ei suojattu auringonpaisteelta. 5. Varastointi taimipenkissä. Taimet saivat istutushetkeen saakka kasvaa alkuperäisissä paikoissaan taimipenkissä sen jälkeen kun kaikkiin muihin käsittelyihin käytettävät taimet oli niille sattumanvaraisesti määräytyneistä penkkien kohdista jo nostettu. 10 Olavi Huuri 79.5 Kuva 2. Eri tavoin varastoitujen taimien noston, varastoonpanon ja istutuksen ajankohdat sekä erilaisten varastointien kestoajat. Istutusmerkk kien takana olevat numerot ilmoittavat varastointiaikojen pituudet vuorokausina. Figure 2. Time of lifting, storage, and planting, and the duration of storage of transplants. The numbers following the respective signs indicate the length of storage in days. 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 11 Kaikki edellä esitetyt varastoinnin suoritustavat olivat kokeen perusta misen aikana metsänviljelyn kenttätyössä realistisiksi katsottavia toiminta vaihtoehtoja istutuksen ajankohtaa lykättäessä. Koejärjestelyssä niitä erilai sine kestoaikoineen voitaneen myös pitää erilaisina käsittelyinä, vaikka jois sakin vaihtoehdoissa (5) ei taimia ennen istutusta käsin kosketeltukaan. Vuonna 1964 perustetussa kokeessa A taimet nostettiin taimitarhasta 26. 5. (kuva 2) ja ne sijoitettiin arvotuin käsittelyerin välittömästi kellariin (suoritustapa 1), valeistutukseen (2) ja ojaveteen (3). Suoritustavalla 5 (taimipenkki) varastoitavat taimet jäivät kuitenkin edelleen kasvamaan pai koilleen. Eripituiset varastointiajat kellarissa, valeistutuksessa ja ojavedessä olivat siten A-kokeessa 14 vrk., 29 vrk. ja 41 vrk. (kuva 2). Kokeessa B, jolla haluttiin varmistaa A-kokeella saatuja tuloksia, taimet nostettiin varastointeja I—4 varten 17. 5. 1966 (kuva 2). Ennen varsinaisen varastointikokeen aloittamista pyrittiin taimia kuitenkin käytännön olosuh teita mukaillen heikentämään pitämällä niitä esivarastoinnissa edellä kuva tussa talouskellarissa 20 vuorokauden ajan. Tämän jälkeen sijoitettiin arvo tut taimierät varastointeihin 2—4 kellari varastoinnin jatkuessa kuitenkin käsittelyerän 1 (kellari) osalta sellaisenaan ja taimipenkissä varastoitavien taimien (5) kasvaessa edelleen alkuperäisillä paikoillaan. Tässä kokeessa olivat varastointiajat siten: kellarissa 20 vrk., 27 vrk., 34 vrk., 41 vrk., 48 vrk. ja 55 vrk. sekä valeistutuksessa, ojavedessä ja kaivovedessä esivaras toinnin jälkeen 7 vrk., 14 vrk., 21 vrk., 28 vrk. ja 35 vrk. (kuva 2) sekä taimipenkissä muiden taimierien noston jälkeen 20 vrk., 27 vrk., 34 vrk.. 41 vrk., 48 vrk. ja 55 vrk. 23. Testisarjat ja niiden perustaminen Kokeen tuloksia ei käytännöllisistä syistä voitu mitata fysiologisia mää rityksiä tai mittauksia käyttäen. Siitä syystä jäi ainoaksi keinoksi testata varastoinnin vaikutuksia istuttamalla taimet heti varastointien päättyessä ja seuraamalla niiden kehitystä istutuksen jälkeen. Oletettiin, että eri ajan kohtina suoritettujen istutusten tulokset kuvastavat niitä taimiin kohdistu neita yhteisvaikutuksia, jotka aiheutuvat varastoinnin suoritustavasta, va rastoinnin kestosta ja itse istutuspaikan olosuhteissa kesän edistyessä tapah tuneista muutoksista. Koko tämä vaikuttajakompleksi kulkeekin ehjänä kokonaisuutena mukana myös käytännön metsänviljelytyössä istutuksen ajankohtaa syystä tai toisesta lykättäessä. Koska nyt suoritetuissa kokeissa istutuspaikan olosuhteet olivat saman kokeen kaikille taimierille samat ja vain varaston laatu ja varastointiaika vaihtelivat, kuvastanee tutkimuksen tulos varastoinnin erilaisten suoritustapojen vaikutusta taimien elinvoimaan eri ajankohtina suoritetun istutuksen jälkeen. Tässä mielessä antaa koe myös kuvan kunkin suoritustavan käyttökelpoisuudesta metsänviljelyssä. 12 Olavi Huuri 79.5 Kuva 3. A-kokeen testialuetta viisi kasvukautta istutuksen jälkeen. Figure 3. Test area of experiment A five years after planting. Sen vuoksi kaikki kokeessa olleet taimet istutettiin heti varastointien päättyessä testisarjoihin erikseen A- ja B-kokeiden osalta. Istutukset testi sarjassa A suoritettiin ajankohtina 26. 5., 9. 6., 24. 6. ja 6. 7. 1964. B-testi sarjassa taas olivat istutusten ajankohdat 6. 6., 13. 6., 20. 6., 27. 6., 4. 7. ja 11. 7. 1966 (kuva 2). Molemmat testisarjat istutettiin rehevälle käenkaali—mustikkatyypin kasvupaikalle tiheähkön leppäverhopuuston suojaan (kuva 3) noin 600 met rin etäisyydelle toisistaan. Paikan maantieteellinen pituus on 25°58' ja leveys 61°29'. Kummankin alueen maaperä on hiesusavea, jota peittää pak suhko mineraalimaansekainen humuskerros. Istutuskokeet järjestettiin ar vottujen lohkojen periaatteen mukaisesti. Eri varastointikäsittelyt esiintyi vät A-kokeessa kahtena ja B-kokeessa viitenä viiden taimen suuruisena tois toruutuna. Kussakin ruudussa yksi taimi sijoitettiin keskelle ja muut noin puolentoista metrin etäisyydelle siitä, lähelle ruudun kulmia. Testisarjo jen yhteinen ruutuluku on 176 ja taimien kokonaismäärä 880. Molemmissa kokeissa käytettiin kuusentaimien istutuksen nykyisin yleisintä suoritustapaa, ns. kuopan laitaan istutusta SFJ-kourukuokalla (esim. Huuri 1972). Kummassakin testisarjassa pyrittiin myös siihen, että sama henkilö olisi suorittanut istutukset läpi koko kokeen. A-kokeen verhopuusto on säilytetty miltei alkuperäisenä (kuva 3), mutta B-kokeen päältä sitä on harvennettu kahteen otteeseen. Molempien koealueitten rehe välle maaperälle kehittynyttä pitkää ja tiheätä ruohostoa ja heinästöä on 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 13 Kuva 4. Kesäkuukausien sadesummat (mm) ja lämpösummat (degree days, d.d.) Heinolan (H) ja Mikkelin (M) sääasemilla vuosina 1964 ja 1966. Sadesummien kohdalla paksu viiva kuvaa vuosien 1931—1960 keskiarvoa. (Ilmatieteellinen Keskuslaitos 1965 ja 1967) Figure 4. The rain sums (mm) and temperature sums (degree days, d.d.) during the summer months at Heinola (H) and Mikkeli (M) climate stations in 1964 and 1965. The heavy line for rain sums indicates the mean of 1931—1960. (Finnish Meteorological Office 1965 and 1967) torjuttu vain polkemalla sitä maalian taimien ympärillä syksyisin suoritettu jen inventointien yhteydessä. Heinästö on vaikuttanut taimien pituuskehi tykseen häiritsevästi, mutta ei ole voinut merkittävästi vaikuttaa niiden kuolleisuuteen, mikäli taimet ovat olleet istutettaessa hyväkuntoisia. 1964 1966 1 8 0 1 60 1 40 1 20 100 80 60 40 20 ■■ V VI VII VIII IX V VI VII VIII IX 300 . Z. dd /У \ -- / \ 20 0 - / \ " / \ - 100 'M - \h M 1 1 1 1 1 1 1 1 1 1 V VI VII VIII IX V VI VII VIII IX 14 Olavi Huuti 79.5 Kokeiden suorittamisvuodet 1964 ja 1966 olivat keskinkertaista tuntu vasti lämpimämmät (kuva 4). Näin oli asian laita erityisesti vuoden 1966 kohdalla. Myös kosteusolot olivat vuonna 1966 keskimääräistä suotuisammat heinäkuusta kesän loppuun saakka. Sen sijaan vuosi 1964 oli sangen niuk kasateinen etenkin kesä — heinäkuun osalta. 24. Mittaukset ja havainnot Testisarjat on istutuksen jälkeen inventoitu syksyisin miltei vuosittain. Päähuomio on kiinnitetty taimien elossaoloon, kuntoon ja pituuskehitykseen. Jokaisen kokeeseen istutetun taimen osalta määriteltiin sen kunto inven tointihetkellä seuraavaa luokitusta käyttäen: a. Vahvat, rehevät taimet, jotka vetävät vertoja vastaa vissa oloissa kasvaneille, samanikäisille, terveille luonnontaimille. b. Normaalikuntoiset istutustaimet. Nämä eivät alkuvuosina ole vastaavissa oloissa kasvaneiden luonnontaimien veroisia, mutta näyttävät todennäköisesti selviävän istutuksen niille aiheuttamista rasituksista ja saavuttavan muutaman juromisvuoden jälkeen luonnontai mille vertoja vetävän rehevyyden ja kasvun. c. Lievästi kärsineet taimet, joissa heikentymisen merk keinä näkyy esim. neu las ton harvuutta tai kellertävää väriä, varren hen toutta tai ohimeneviltä tuntuvia muita heikkouden merkkejä. d. Pahoin kärsineet, lähes kuolemaisillaan ole vat taimet, joiden maanpäällisissä osissa on kuitenkin heikoimmissakin tapauksissa todettavissa vielä tuoreutta ja ainakin joissakin neulasissa myös vihreätä tai keltaista väriä. Parhaassakin tapauksessa tällaiset taimet ovat erittäin heikkoja ja vain harvoin toipumiskykyisiä. e. Kuolleet taimet, joiden maanpäälliset osat ovat ruskettuneet ja kuivuneet. Päärangan viimeinen vuosiverso mitattiin kaikilla inventointikerroilla jokaisesta elossaolevasta taimesta puolen senttimetrin tarkkuudella. Myös alkuperäiset taimitarhapituudet mitattiin ensimmäisellä inventointikerralla jokaisesta istutetusta taimesta. Tätä varten etsittiin juurenniska, josta läh tien pituus mitattiin taimitarhavaiheen latvasilmun tyveen. Käytännöllisistä syistä tämän katsottiin sijaitsevan latvaan silmujen suojaksi muodostuneen neulaskiehkuran alkamiskohdassa. Mittausta silmujen kärkeen ei käytetty, koska silmun pituus saattoi vaihdella sen kasvuvaiheesta riippuen. Tiheän neulaskiehkuran tyvi sen sijaan oli miltei aina selvästi todettavissa ja sen paikka jää myös rungolle näkyviin moniksi vuosiksi. Vuosiversojen pituus voitiin saada mitatuksi myöhemminkin vanhoja oksakiehkuroita hyväksi käyttäen. Kiehkuroitten välimatkat mitattiin tässä tapauksessa oksien yläpinnasta toisen oksakiehkuran oksien yläpintaan. 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 15 Kuva 5. A-kokeen taimia valokuvattuina 9. 6. 1964 Vasemmanpuoleiset taimet ovat olleet 14 vuorokautta kellarissa ja oikeanpuoleiset taimet 14 vuorokautta valeistutuksessa varastoituina. Figure 5. Transplants of experiment A. photographed on June 6, 1964. Transplants to the left have been in the cellar for 14 days and those to the right have been heeled-in for 14 days. Varsinaisten inventointimittausten ja -havaintojen lisäksi tehtiin eri is tutuskertojen yhteydessä havaintoja myös sillä kertaa istutettavien ja aikai semmin istutettujen taimien kunnosta. Näistä havainnoista on mainintoja esitetty kappaleessa 31. tutkimusten tuloksia selostettaessa. Myös lukuisin värivalokuvin pyrittiin tallettamaan tietoa eri varastoista ja taimien ulko näöstä varastoinnin eri vaiheissa. Niistä valmistettuja ovat esim. kuvat 1 ja 5. 25. Tulosten laskenta Koska kuhunkin ruutuun oli istutettu vain viisi tainta, olisi laskennassa ollut saatavissa ruutujen sisäisestä vaihtelusta vain 20 %:n ryhmiin jakau tunut karkea kuva. Tästä syystä tuloksia ei käsitelty taimikohtaisina, vaan aluksi laskettiin ruuduittaiset keskiarvot ja niiden avulla edelleen eri käsit telyille keskiarvot sekä näille luotettavuusrajat 95 %:n todennäköisyydellä. Laskenta suoritettiin kummallekin testisarjalle erikseen, koska olosuhteet niissä poikkesivat toisistaan B-kokeessa varsinaisia varastointikäsittelyjä edeltäneen kellarivarastoinnin takia. 3. TUTKIMUKSEN TULOKSET 31. Varastoinnin suoritustavan vaikutus taimien eloonjäämiseen ja kuntoon 311. Varastointi talouskellarissa Varastoinnin tämän suoritustavan vaikutukset taimien kuntoon ja kuol leisuuteen nähdään kuvassa 6. Kappaleessa 24. esitetyn kuntoluokituksen mukaisesti on siinä erilaisin varjostuksin (vrt. kuvan merkkiselitys) esitetty, millaisiin taimien kuntoryhmiin pitkittynyt kellari varastointi on sijoittanut taimet istutuskesän syksynä (osakuvat I), seuraavan vuoden syksynä (osakuvat II) ja syksyllä 1970 (osakuvat III). Tähän vuoteen mennessä ovat A-kokeen taimet kehittyneet seitsemän ja B-kokeen viisi kasvukautta maastossa. Kuvasta nähdään A-kokeen osalta, että talouskellari on neljän viikon ajan sangen luotettava taimivarasto. Näin pitkään varastoidut ja kesäkuun lopulla, jopa juhannuksen tienoilla, istutetut taimet näyttävät kaikki jääneen henkiin, joskin heikkokuntoisuutta ilmenee kahden ensimmäisen kasvu kauden aikana yli viidesosalla taimista. Kun varastointiaika on pidentynyt kuudeksi viikoksi, taimet alkavat kuitenkin heikentyä niin suuressa määrin, että kuolleisuus A-kokeessa jo toisena kesänä nousee lähes 40 %:iin ja seitse män vuoden päästä se on 41 vrk. kellarissa varastoitujen taimien keskuu dessa noussut jo 50 %:iin. Hyvin samanlainen on kehitys ollut myös kahta vuotta myöhemmin perustetussa kokeessa B. Vasta neljän viikon varastoinnin jälkeen alkaa ilmetä kuolleisuutta, ja kahdeksan viikon kellari varastoin ti on johtanut jo 50 %:n ylittävään kuolleisuuteen. Mielenkiintoinen havainto taimien sitkeä henkisyydestä on tehtävissä ensimmäisen ja toisen syksyn tuloksia ver taamalla. Ensimmäisen kasvukauden lopulla (kuva 6, osakuva B I) ei kuolleisuutta vielä ilmene lainkaan. Tällöin pahoin kärsineiksi luokitel lut taimet ovat kuitenkin seuraavan vuoden inventointiin mennessä kaikki kuolleet (osakuva B II). Lievästi kärsivien taimien määrä on vuosien mittaan vähentynyt toipumisen kautta. Kuitenkaan tämä ryhmä ei ole kokonaan hävinnyt kummastakaan testisarjasta, vaikka kaikkein heikoimmat taimet ovatkin inventointihavaintojen mukaan vuosien mit taan kuolleet. 3 17138—73 Kuva 6. Kellarissa varastoitujen kuusentaimien kunto ja kuolleisuus testisarjassa A vuosina 1964, 1965 ja 1970 sekä testisarjassa B vuosina 1966, 1967 ja 1970. Vaaka-akselilla istutuksen ajankohta ja varastoinnin pituus vuorokausina. Pystyakselilla taimien jakautuminen kuntoluokkiin inven tointivuotena, joka on merkitty kuvaruudun yläpuolelle. Figure 6. The condition and mortality of spruce transplants stored in cellar in test series A in 1964, 1965, and 1970, and in test series B in 1964, 1967, and 1970. Abscissa = the date of planting and the duration of storage in days, ordinate = the distribution of the transplants into condition classes in the year of survey, indicated above the frame. Olavi Huu r i 79.r, 18 Kuva 7. Talouskellarissa 48 vuorokauden ajan varastoituja B-kokeen taimia valokuvattuina 4. 7. 1966. Figure 7. Transplants of experiment B stored 48 days in a cellar. Photograph July 4, 1966. Pitkittyneen kellarivarastoinnin vaikutuksia taimiin valaisevat myös kuvat 5 ja 7 sekä istutusten yhteydessä tehdyt muistiinpanot: Pitkittynyt kellarivarastointi johti uusien kasvainten kellastumiseen sekä juurien heikkenemiseen homeiden takia ja taimien juurtumiskyvyn heikke nemiseen epäilemättä myös siten, että ravinnevarastot ehtyivät yhteyttämis Kokeen tunnus Kellari- varastoinnin pituus Taimia koskevat havainnot Koe A . . . . 14 vrk. Uudet versot n. 1 cm. Kellertävän vihreitä (kuva 5). » 29 » Versot vaaleankeltaisia, 4—5 cm. Juurissa hometta. Versot keltaisia, heikkoja. Juurissa ja tyvissä hometta. 41 » Koe В . . . . 20 vrk. Silmut 0—1 cm. Kellertäviä. Juuret tuoreita, muutamia pitkiä kasvukärkiä. » 27 » Versot 1—3 cm. Vaaleankeltaisia. Juurissa runsaasti kasvukärkiä. » 34 » Versot vaal.kelt., 1—3 cm. Juuret tuoreet. Runsaasti kasvukärkiä. » 48 »> Kalpean keltaiset uudet versot kasvaneet jopa 5 cm:n pituisiksi. Juuret märkiä. Niissä ei hometta mutta kylläkin lievää hajua. 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 19 Kuva 8. Valeistutuksessa varastoitujen kuusentaimien kunto ja kuolleisuus testisarjassa A vuosina 1964,1965 ja 1970 sekä testisarjassa B vuosina 1966,1967 ja 1970. Merkinnät samat kuin kuvassa 6. Figure 8. The condition and mortality in 1964, 1965, and 1970 in test series A, and in 1966, 1967, and 1970 in test series B of heeled-in spruce transplants. Legend as in Figure 6. mahdollisuuksien puuttuessa sekä hengityksen ja muiden elintoimintojen kuluttaessa niitä puolilämpimässä kellarissa. A- ja B-kokeiden välille ei näytä kehittyneen silminnähtäviä eroja tuloksissa. Tämä onkin ymmärret tävää, koska B-kokeessa taimien heikentämiseen tähtäävä käsittely oli kel larivarastointia kuten A-kokeessakin. 312. Varastointi valeistutuksessa Valeistutuksessa varastoinnin antamia tuloksia esittää kuva 8, joka on laadittu samalla tavoin kuin kuva 6. Voidaan nähdä, että taimien säilyttä minen ulkoilmassa ja niiden juurien peittäminen maahan on taimien kunnon kannalta tuntuvasti suotuisampi varastointimuoto kuin varastointi kellarin pimeydessä ja kosteudessa. Tämä voidaan nähdä myös kuvasta 5. 20 Olavi Huuri 79 Kuva 9. Valeistutuksessa 28 vuorokauden ajan varastoituja B-kokeen taimia. Tällaisten taimien eloonjääminen istutuksen jälkeen oli sangen hyvä, vaikka tiheästä varastointiasennosta johtuen alimpien oksien uudet neulaset olivatkin kehittyneet väriltään keltaisiksi. Valok. 4. 7. 1966. Figure 9. Transplants of experiment B heeled-in for 28 days. Survival of such transplants after planting wawas rather high in spite of the needles of the lower branches having turned yellow due to density of storage. Photograph July 4, 1966. Kuolleisuutta alkaa esiintyä A-kokeessa vasta, kun taimet ovat olleet valeistutuksessa runsaasti yli kuukauden ja ne on istutettu niin vaikeana ajankohtana kuin heinäkuun alussa. Kuolleisuus ei tästäkään huolimatta lainkaan lisäänny seitsemän seuraavan kasvukauden aikana, vaikka lievää kärsineisyyttä ilmeneekin taimissa jatkuvasti. Se ei luultavasti kuitenkaan johdu varastoinnista eikä istutuksen ajankohdasta, vaan tiheästä verho puustosta, joka on jatkuvasti varjostanut A-kokeen taimia. Myös kaksi vuotta myöhemmin perustetun B-kokeen taimet kehittyvät miltei samoin kuin A-kokeenkin. Taimien kunto, ehkä lievemmän varjostuk sen takia, on kuitenkin nyt kauttaaltaan hieman parempi. Kuolleisuutta 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 21 alkaa nytkin esiintyä vähäisessä määrässä vasta varastointiajan lähetessä neljää viikkoa. Ne havainnot, jotka eri istutuskerroilla valeistutuksessa olleista taimista tehtiin, toivat näkyviin valeistutuksen haitoista mm. taimien tiheän varas tointiasennon, minkä johdosta ryhmien sisälle jääneiden taimien uudet versot kellastuivat (kuva 9). Vertailtaessa heikentämättömillä A-kokeen taimilla saatuja tuloksia 20 vrk:n kellarivarastoinnilla heikennettyjen B-kokeen taimien antamiin ei johdonmukaisia eroja voida havaita. Taimien kunnon heikentämiseen tähtää vän esivarastoinnin vaikutus lienee ollut liian lyhytaikainen. 313. Varastointi ojavedessä Kuva 10, joka esittää ojavedessä varastoinnin vaikutuksia taimiin, näyt tää jyrkästi huonompaa tulosta kuin edellä tarkastellut. Kehitys kokeessa A varastointiaikojen 0 vrk. ja 14 vrk. välillä ei kuiten kaan todellisuudessa kulje aivan niin suoraviivaisesti kuin osakuvien 10 A I—III interpoloidut kuvaajat esittävät. Sen sijaan on varmaa, että kahden viikon pituinen varastointi on jo ensimmäiseen syksyyn mennessä rusketta nut lähes 90 % taimista niin, että ne on arvioitu kuolleiksi. Pitempi, 29 vuo rokauden varastointi on ollut tulokseltaan tätä vielä hieman huonompi ja 41 vuorokauden varastoinnissa ovat taimet kärsineet niin pahoin, että ne jo ensimmäisen maastokasvukauden loppuun mennessä ovat kaikki kuolleet. Seuraavan kasvukauden syksynä kuitenkin todettiin, että osa 14 vuorokautta varastossa olleista, kuolleiksi luokitelluista taimista olikin toipunut ja osoit tautunut tässä inventoinnissa eläviksi taimiksi. Kahta viikkoa pitempään varastoidut taimet sen sijaan olivat säilyneet siinä kuntoluokassa, mihin ne oli sijoitettu jo edellisen syksyn inventoinnissa. Seitsemännen kasvukauden loppuun mennessä nämä taimet olivat jo kaikki kuolleet. Kahta vuotta myöhemmin perustetussa B-kokeessa olivat varastointi aikojen erot puolta lyhyemmät, vain yhden viikon pituiset. Tämä järjestely salli kuolleisuuden muutoksien piirtyä yksityiskohdiltaan tarkempina ja osoittaa selvemmin, miten pitkään taimia voidaan varastoida ojavedessä. Nytkin on taimille tuhoisia seurauksia alkanut näkyä varastoinnin ylittäessä kahden viikon ajan. Kolmen viikon varastointi johti jo ensimmäisen kesän loppuun mennessä siihen, että miltei kaikki taimet olivat kuolemaisillaan pääosan kuuluessa jo kuolleitten ryhmään. Tämä tilanne on varmistunut seuraavan kasvukauden aikana, jonka jälkeen aivan valtaosa yli kolme viik koa ojavedessä varastoiduista taimista on kuollut. Lyhyet varastointiajat ovat nyt mielenkiintoiset, koska ne osoittavat kuusentaimien kestävän täl laista varastointimuotoa noin 7 vuorokauden ajan melko vähäisin vaurioin 22 Olavi Huuri 79. s Kuva 10. Ojavedessä varastoitujen kuusentaimien kunto ja kuolleisuus testisarjassa A vuosina 191964, 1965 ja 1970 sekä testisarjassa B vuosina 1966,1967 ja 1970. Merkinnät samat kuin kuvassa 6. Figure 10. The condition and mortality in 1964,1965, and 1970 in test series A, and in 1966, 1967, and 1970 in test series B of spruce transplants stored in ditch water. Legend as in Figure 6. Tällöin istutetut taimet ovat nimittäin säilyneet elossa siksi hyvin, että kuol leisuutta esiintyy myöhemminkin sangen vähän, alle 10 %. Eri istutuskerroilla tehdyt havainnot kertovat taimissa istutushetkellä näkyvistä varastointivaurioista mm. seuraavaa: Taimia koskevat havainnot Uudet versot n. 1 em, epätasaisesti venyneitä, vihreitä. Versot 2—3 em pitkiä. Hyvin erilaisissa vaiheissa kehi tyksessään. Taimet jokseenkin huonokuntoisia. (Edelli sellä kerralla istutetuista taimista on tehty merkintä: Yli puolet taimista heikossa kunnossa. Latvat kellertävän ruskeita. Heikkokuntoiset taimet eivät ole ollenkaan kas vaneet. Osa taimista jo täydellisesti ruskettuneita. Osalla tyviosassaan tuoreita oksia). Kokeen Ojavesi- varastoinnin tunnus pituus Koe A . . . 14 vrk. » .... ... 29 » 79..-, Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 23 Kuva 11. Ojavedessä 28 vuorokauden ajan varastoituja B-kokeen taimia. Tällaiset taimet kuolivat miltei kaikki jo istutuskesän aikana. Varastoinnin aikana kasvaneet uudet versot jäivät riippuviksi ja ruskettuneiksi. Juuret ja taimien tyvet mustuivat. Valok. 4. 7. 1966. Figure 11. Transplants of experiment B stored in ditch water for 28 days. Almost all such seedlings died during the first growing season. The shoots which expanded during storage remained drooping and brown. The roots and the base of the stem turned black. Photograph July 4 1966. Kaikki taimet huonossa kunnossa. Usein latva ja koko taimikin mustunut, joskus lähes kokonaan vihreä. Versot 2—4 em, usein uudet versot ruskeat. Verso 2—3 cm, vaal.vihreä. Juuret tuoreita, mustahkoja. Ojavesitaimilla versot lyhyimmät. Juurissa kasvupisteitä. Ojataimet surkeassa kunnossa. Uusista versoista vain lat vat vihreät, nekin lerpallaan. Alempien oksien päät rus kettuneet ja jopa homehtuneet. Juurissa paha haju, kiil tävä pintakalvo (kuva 11). Luonnossa tavattavat allikot ja virtaavan veden uomat voivat paljonkin vaihdella veden laadun suhteen. Nyt kokeillussa tapauksessa saattoi mudan hiljainen liikkuminen ja takertuminen taimien alaosan peitoksi aiheuttaa osan kuolleisuudesta. Taimien heikentäminen esivarastoinnilla B-sarjassa ei nytkään ole aiheut tanut tuloksiin näkyvää eroa. Näyttää jopa siltä kuin B-sarjan taimet olisivat Кое А ... 41 vrk Кое В 7 vrk » 14 » » ... 28 » 24 Olavi Huuti 79..-, kestäneet varastointia ojavedessä hieman paremmin kuin täysikuntoisina varastoidut A-sarjan taimet. Kokeet on kuitenkin tehty eri vuosien erilaisissa olosuhteissa ja tämä huonontaa vertailumahdollisuuksia. 314. Varastointi kaivovedessä Tätä varastoinnin suoritustapaa kokeiltiin vain vuonna 1966 perustetussa B-kokeessa. Ojavedessä varastoimisen huonojen tulosten alustavasti selvit tyä haluttiin kokeilla, oliko sen aiheuttaman suuren taimikuolleisuuden syynä juurten tukehtuminen veden hapettomiin oloihin, vai jokin ojaveteen liittyvä epäpuhtaus tms. Varastoinnin tässä suoritustavassa kokeiltiin puhdasta kaivovettä, joka vaihdettiin uuteen kaivosta otettuun vesierään kerran vii kossa. Tämän kokeen tulos esitetään kuvassa 12. Kuva 12. Kaivovedessä varastoitujen kuusentaimien kunto ja kuolleisuus testisarjassa B vuosina 1966, 1967 ja 1970. Merkinnät samat kuin kuvassa 5. Figure 12. The condition and mortality in 1966, 1967, and 1970 in test series B of spruce transplants stored in well water. Legend as in Figure 6. Taimien kuolleisuus on nyt selvästi vähäisempää kuin varastoitaessa oja veteen. Kuitenkin kuolleisuutta alkaa esiintyä jo ensimmäisen kasvukauden aikana taimilla, joiden varastoinnin pituus ylittää kahden viikon ajan. Ensimmäisen kasvukauden syksynä on myös kuolemaisillaan olevien taimien määrä merkittävän suuri kolmeviikkoisessa ja sitä kauemmin kestävässä varastoinnissa. Kuolemaisillaan olevien taimien määrä ylittää jopa 50 % viiden viikon varastoinnissa ja näistä taimista kuolee yli puolet toisen kasvu kauden aikana. Kuolleisuus ei kuitenkaan enää seuraavina kasvukausina lisäänny. 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 25 4 17138—73 Kuva 13. Kaivovedessä 28 vuorokauden ajan varastoituja B-kokeen taimia, joiden alaoksien uudet versot ovat kellastuneet tiheästä varastointiasennosta johtuen ja juuret sekä taimien tyvet mus tuneet veden vaikutuksesta. Valok. 4. 7. 1966. Figure 13. Transplants of experiment B stored for 28 days in well water. The new shoots of the lower branches have turned yellow due to the dense storage, and the roots and the base of the stems have turned black because of the effect of the water. Photograph July 4, 1966. Seuraavia havaintoja on tehty kaivovedessä varastoitujen taimien kunnosta: Taimia koskevat havainnot Versot n. I—31 —3 cm, vaalean vihreitä, juuret hyväkuntoisia, niissä runsaasti kasvupisteitä. Kaivovesitaimet selvästi ojataimia parempia, joskin juu rissa hajua jonkin verran. Nippujen sisässä keltaisia ver soja, valonpuutteesta johtuen. Valossa kehittyneet versot vihreitä ja voimakkaita. Käsityksen viimemainittujen taimien ulkonäöstä antaa myös kuva 13. 315. Varastointi taimi penkissä Eräs muoto lähellä istutuspaikkaa suoritettavaa taimien varastointia on koulintataimitarhojen perustaminen korkeintaan tunnin automatkan päähän istutuspaikoista ja taimien jakeleminen istutusaloille pienin päiväerin tiheätä Kokeen Kaivovesi- varastoinnin tunnus pituus Кое В ... 7 vrk. » .... ... 28 » 26 Olavi Huuri 79.r> Kuva 14. Taimipenkissä varastoitujen kuusentaimien kunto ja kuolleisuus testisarjassa A vuosina 1964, 1965 ja 1970 sekä testisarjassa B vuosina 1966, 1967 ja 1970. Merkinnät samat kuin kuvassa 6. Figure 14. The condition and mortality in 1964, 1965, and 1970 in test series A, and in 1966, 1967, and 1970 in test series B of spruce transplants stored in the nursery bed. Legend as in Figure 6. metsätieverkkoa hyväksikäyttäen. Tällaista taimien korkeintaan tunnin pituista kuljetusta ja varastointia tutkittiin vuonna 1966 kokeessa B (kuva 14, B I—III). Taimien aivan välitöntä siirtämistä istutusalan lähellä olevasta koulintataimitarhasta istutukseen taas käytettiin vuoden 1964 A-kokeessa (kuva 14, A I—III). Viimemainitusta osakuvasta ilmenee, että varjoiselle kuusen uudistus alalle hyväkuntoisina istutetut A-kokeen taimet ovat selvinneet keski kesänkin lämpiminä ajankohtina suoritetuista istutuksista aivan ilman taimi tappiota. Ensimmäisen kasvukauden lopulla on kaikki aikavälillä 26. 5.—• 6. 7. istutetut taimet luokiteltu normaalikuntoisiksi tai niitä rehevämmiksi. Tällöin ei taimissa ole näkynyt lieviäkään kärsimisen merkkejä. Kun kärsi Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 79.r, 27 Kuva 15. B-kokeen taimia, jotka ovat istutushetkeen 4. 7. 1966 saakka saaneet rauhassa kasvaa tataimipenkissään. Tällaiset taimet jäivät eloon ja kehittyivät maastossa istutuksen jälkeen odotta mattoman hyvin, vaikka istutushetkellä niiden uudet versot olivatkin jo kehittyneet pitkiksi ja pehmeiksi. Figure 15. Transplants of experiment B. The seedlings have developed intact until time of planting on July 4, 1966. Such seedlings survived and developed in the field unexpectedly well in spite of the fact that their expanding shoots were already long and succulent. neisyyttä alkaa ilmetä seuraavana kasvukautena, esiintyy sitä vain sellai sissa taimierissä, jotka on istutettu juhannuksen tienoilla ja heinäkuun alku päivinä, jolloin uudet versot olivat kehittyneet täysimittaisiksi, mutta olivat vielä puutumattomina voimakkaasti haihduttavia. Myöskin vuonna 1966 perustetun B-kokeen osalta (kuva 14, B I — III) voidaan tehdä samantapainen havainto. Ensimmäisen kasvukauden aikana ei taimia ole kuollut lainkaan. Toisen kasvukauden aikana (osakuva B II) ilmenee kuolleisuutta erittäin vähän, joskin taimien lievää kärsineisyyttä esiintyy runsaanpuoleisesti. Viidennen kasvukauden loppuun mennessä on huonokuntoisten taimien osuus kuitenkin huomattavasti vähentynyt. Tai met ovat nyt miltei kaikki normaalikuntoisia ja kuolleisuus niiden joukossa on edelleen pysynyt aivan vähäisenä. Käsityksen heinäkuun alussa istutet tujen taimien ulkonäöstä antaa kuva 15. Kuvan esittämässä kasvuvaiheessa olevat kuusentaimet jäivät kaikki eloon erittäin vaikeana pidetystä istutus ajankohdasta huolimatta. 28 Olavi Huuti 79.r, 316. Varastojen vertailua Pyrittäessä vertailemaan kokeiltuja varastoja toisiinsa on niiden käyttö kelpoisuuden mitaksi tässä valittu sen ajan pituus, jonka varastointi saa vaikuttaa taimiin ilman, että taimien kuolleisuus seuraavien viiden kasvu kauden aikana ylittää 10 %:n rajan. Tämän mukaan sijoittuivat nyt tutkitut varastot seuraavan asetelman mukaiseen järjestykseen parhaimmasta huonoimpaan luetellen: Kokeessa A erottui varastointi ojavedessä (3) jo 9. 6. suoritetusta istu tuksesta alkaen tilastollisesti merkitsevästi toisista käsittelyistä niitä hei kompana. B-kokeessa taas oli ojavarastoinnin huonommuus 95 %:n toden näköisyydellä merkitsevä muihin varastoinnin suoritustapoihin nähden istu tuksissa 27. 6., 4. 7. ja 11. 7. Myös kellarivarastointi jää muita huonommaksi lähes merkitsevästi 4. 7. suoritetussa istutuksessa ja merkitsevästi 11. 7. suoritetussa istutuksessa. Puhtaassa vedessä varastointi on merkitsevästi muita varastointitapoja heikompi istutuksessa 11. 7. Pisimmässä varastoin nin kestossa ja molemmissa kokeissa erottuvat muista tilastollisesti mer kitsevästi parhaiksi ne varastoinnit, joissa taimet saivat olla luonnon - mukaisimmissa olosuhteissa, versot auringonpaisteessa ja vapaasti liikku vassa ilmassa sekä juuret mullan peitossa. 32. Varastoinnin suoritustavan vaikutus taimien kokonaispituuteen ja vuotuiseen pituuskasvuun Paitsi taimien eloonjääminen, on metsänviljelyn tulokselle tärkeä myös kin taimien kasvu, ennen kaikkea taimien päärangan pituuskehitys. Tämän havainnollistamiseksi A-kokeen osalta on piirretty kuva 16, jossa eri pituis ten varastointien tulokset on koottu yhtenäiseksi sarjaksi. Kuvasta voidaan tehdä seuraavat havainnot: Lepikon varjostamalla kasvupaikalla (kuva 3) ovat nopeimmin kehit tyneet A-kokeen taimet saavuttaneet vasta noin metrin keskimääräisen pituuden, vaikka istutuksesta on kulunut jo seitsemän kasvukautta ja taimet ovat viimeisessä mittauksessa olleet kylvöstä lukien 11 vuoden ikäisiä. Varasto Varastointiaika, jonka jälkeen taimien kuolleisuus ylittää 10 % 1. Taimipenkki Edellämainittua varastointiajan vaarallista ylärajaa ei kokeessa lainkaan kohdattu 2. Valeistutus . . . Varastoinnin vaaraton kestoaika n. 5—6 viikkoa 3. Kellari Vaaraton kestoaika korkeintaan 4 viikkoa 4. Kaivovesi Vaaraton kestoaika korkeintaan 2 viikkoa 5. Ojavesi Vaaraton kestoaika korkeintaan 1 viikko 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 29 Parhaiten elossa pysyneet taimet (kuvat 8 ja 14), jotka oli varastoitu taimipenkissä (5) tai valeistutuksessa (2), ovat saavuttaneet yleensä myös suurimman keskipituuden. Suoraan taimipenkistä istutettujen taimien pituus näyttää olevan sitä suurempi mitä myöhemmin kasvukauden aikana taimet on istutettu. Niinpä heinäkuun istutuksessa (osakuva D) taimitarha taimien (5) pituus näyttää selvästi suuremmalta kuin kesäkuun alussa (osa kuva B) ja juhannuksen aikoina suoritetuissa istutuksissa (osakuva C). Valeistutuksessa olleet taimet jäävät kasvussaan jälkeen taimipenkissä varas toiduista varastointiajan pidetessä (osakuvat C ja D) vaikkakin 9. 6. istu tetuilla valeistutustaimilla näyttää kasvu olleen erittäin voimakasta. Kel lari varastoinnista eloonjääneiden taimien kasvu heikkenee varastointiajan pidentyessä ja ne näyttävät olevan kokeen lopussa taimitarhataimista selvästi jäljessä. Ojavedessä varastoidut taimet kuolivat jo ensimmäisten kasvukausien aikana niin vähälukuisiksi, että niistä ei voitu tehdä luotettavia pituus mittauksia. Muutamien tehtyjen havaintojen perusteella taimet ovat olleet kokeen koko kehitysajan muiden käsittelyryhmien taimista kasvussaan sel västi jäljessä. Cuva 16. Eri tavoin varastoitujen (1—5) ja eri aikoina istutettujen (A—D) kuusentaimien pituus- [ehitys A-kokeessa. Vaaka-akselilla taimien ikä kylvöstä lukien ja pystyakselilla taimien pituus. Varastoinnin suoritustavat: 1 = kellari, 2 = valeistutus, 6 = taimipenkki. Istutuspäivämäärät v. 1964: A = 26. 5., В = 9. 6., С = 24. 6., D = 6. 7. Varastointiaikojen pituudet: Katso kuva 2. 7 igure 16. Stern height of spruce transplants stored Ъу different methods and planted in different times (experiment A). Abscissa = age of transplants from sowing, ordinate = height of transplants. Methods of storage: 1 = cellar, 2 = heeling-in, 5 = nursery bed. Dates of planting: A — May 26, В = June 9, С = June 24, D = July 6. Duration of storage: See Figure 2. 12 3 456789 123456789 1234567 v. years Kuva 17. Eri tavoin varastoitujen (1—5) ja eri aikoina istutettujen (E—J) kuusentaimien pituus kehitys B-kokeessa. Vaaka-akselilla taimien ikä kylvöstä lukien ja pystyakselilla taimien pituus. Varastoinnin suoritustavat: 1 = kellari, 2 = valeistutus, 3 = ojavesi, 4 = kaivovesi ja 5 = taimipenkki. Istutuspäivämäärät v. 1966: E = 6. 6., F = 13. 6., G = 20. 6., II = 27. 6., I = 4. 7., J = 11. 7. Varastointiaikojen pituudet: Katso kuva 2. Figure 17. Stem height of spruce transplants stored by different methods and planted in defferent times (experiment B). Abscissa = age of transplants from sowing, ordinate = height of transplants. Methods of storage: 1 cellar, 2 = heeling-in, 3 = ditch water, 4 = well water. Dates of planting: E = June 6, F = June 13, G = June 20, H = June 27,1 = July 4, J = July 11. Duration of storage: See Figure 2. Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 31 79.5 Kuva 17 taas esittää B-kokeen taimien vastaavaa pituuskehitystä. Myös nämä taimet ovat kasvaneet verrattain tiheän verhopuuston alla ja vahvan vadelmikon sekä heinästön ahdistamina. Nähdään, että niiden pituuskehitys onkin ollut nopeudeltaan jotakuinkin samanlainen kuin A-kokeen taimien. Osakuvista E—J voidaan B-kokeen taimista tehdä seuraavat eri varas tointikäsittelyjä koskevat havainnot: Nytkin ovat suoraan taimitarhapenkistä istutetut taimet (5) kehitty neet vuoteen 1970 mennessä pitemmiksi kuin muilla suoritustavoilla varas toidut taimet. Näidenkin taimien kokonaispituus alenee kuitenkin hitaasti ajankohdan muuttuessa istutukselle epäsuotuisammaksi. Valeistutuksessa varastoidut taimet (2) eivät varastointikauden lopussa jää paljonkaan jäl keen edellisistä ja myös varastoinnin alussa ne ovat taimitarhataimien kanssa samantasoisia. Pitkittynyt kellarivarastointi (1) jättää myös tai mien pituuskehityksen em. kahdella varastointitavalla saavutettua heikom maksi, vaikka huonommuus ei ole niin suuri kuin eloonjäämisen kohdalla. Taimet, jotka on varastoitu kaivovedessä, ovat edellisiä lyhyempiä, mutta vielä paljon huonompi on pituuskehitys ollut ojavedessä varastoiduilla (3) taimilla. Kaksi luonnonmukaisinta varastointitapaa, varastointi valeistutuk sessa ja varastointi taimipenkissä, näyttävät siis olevan myös pituuskehityk sen kannalta taimille suotuisimmat. Lopuksi on mielenkiintoista tarkastella kuvien 18 ja 19 avulla, ovatko varastoinnin erilaiset suoritustavat vaikuttaneet taimien vuotuisen pituus kasvun määrään tai rytmiin. Tällöin on otettava huomioon, että voimakas heinittyminen on molemmilla koealoilla häirinnyt taimien säännöllistä pi tuuskehitystä. Muutamia havaintoja voidaan kuitenkin tehdä. A-kokeen osalta nähdään kuvasta 18: Ensimmäisen maastokasvukauden verrattain hyvän pituuskehityksen jälkeen seuraa miltei kaikissa käsittelyryhmissä toisena kasvukautena pituus kasvun lyhytaikainen tyrehtyminen. Tämä johtunee siitä, että ensimmäisen kesän kasvun tapahduttua pääasiassa taimitarhalla varastoituneiden ravin teiden turvin ovat toisena kasvukautena siirron aiheuttamat vaikeudet jyr kimmillään. Kasvun hidastuminen on selvin pitkien varastointien jälkeen istutetuilla taimilla. Jo kolmantena kasvukautena kuvaajat kääntyvät kuitenkin nousuun, joka todennäköisesti varjostusten ja heinittymisen vuoksi taas nopeasti kehittyy heittelehtiväksi kasvunopeuden vaihteluksi. Vaihtelut ovat voi makkaimmat osakuvassa L, joka esittää kasvua lyhyen, 14 vrk:n varastointi ajan jälkeen istutetuilla taimilla. Kasvun vaihdellessa jyrkästi näyttävät taimitarhalla varastoidut tai met pysyttelevän muita käsittelyryhmiä hieman edellä niin kasvusaavutuk sissa kuin vaihtelun jyrkkyydessäkin. Osakuvissa M ja N havaittava taimi tarhalla varastoitujen (5) taimien kasvun näennäisesti jyrkkä hidastuminen 32 Olavi Huuti 79.5 Kuva 18. Eri tavoin varastoitujen (1—5) ja eri aikoina istutettujen (K—N) kuusentaimien vuo tuisen pituuskasvun vaihtelut A-kokeessa. Vaaka-akselilla taimien ikä kylvöstä lukien ja pysty akselilla latvakasvaimen pituus. Varastoinnin suoritustavat: 1 = kellari, 2 = valeistutus, 5 = taimipenkki. Istutuspäivämäärät v. 1964: K = 26. 5., L = 9. 6., M - 24. 6. ja N = 6. 7. Varastointiaikojen pituudet: Katso kuva 2. Figure 18. Annual height increment of spruce transplants stored by different methods and planted in different times (experiment A). Abscissa = age of transplants from sowing, ordinate length of the annual shoot. Methods of storage: 1 = cellar, 2 = heeling-in, 5 = nursery bed. Dates of planting: K = May 26, L = June 9, M = June 24, N = July 6. Duration of storage: See Figure 2. viidennen ja kuudennen kasvukauden välillä johtunee pääosaltaan siitä, että viidentenä kasvukautena kesäkuun lopun ja heinäkuun alun istutuk sessa näiden taimien latvaverso on ennättänyt kasvaa erittäin pitkäksi jo taimitarhalla. Todennäköistä on, että tämä kasvu tuntuu taimitarhalle varas toitujen taimien kokonaispituudessakin monta vuotta istutuksen jälkeen ja se voikin olla eräänä selityksenä näiden taimien muita ryhmiä suurempaan pituuteen vielä 5—7 vuoden kuluttua istutuksesta. Toisena, joskin ehkä vähäisempänä syynä tähän tuloksen on kuitenkin myös näiden taimien omaama, jatkuvastikin verrattain hyvä kasvukyky. B-kokeen osalta voidaan kuvasta 19 tehdä seuraavat havainnot: —-Nyt ei pituuskehityksen tyrehtymistä ole tapahtunut istutusta seu raavana kasvukautena lainkaan siinä määrin kuin kokeessa A. Vain varas toinnin suoritustavoissa 3 (ojavesi) ja 4 (kaivovesi) näkyy osakuvista R—T pitkän varastoinnin vaikutus aluksi myös taimien kasvun tyrehtymisenä. Taimipenkissä varastoiduilla taimilla (5) on kasvun väheneminen jyrkkä ja 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 33 5 17138 —73 Varastoinnin suoritustavat: 1 = kellari, 2 = valeistutus, 3 = ojavesi, 4 = kaivovesi ja 5 = taimipenkki. Istutuspäivämäärät v. 1966: 0 = 6. G., P = 13. G., Q = 20. G., R = 27. G., S = 4. 7. ja T = 11. 7. Varastointiaikojen pituudet: Katso kuva 2. Methods of storage: ] = cellar, 2 = heeling-in, 3 = ditch water, 4 = well water, 5 = nursery bed. Dates of planting: 0 = June 6, P June 13, Q = June 20, R = June 27, S = July 4, T = July 11. Duration of storage: See Figure 2. Kuva 19. Eri tavoin varastoitujen (1 —5) ja eri aikoina istutettujen (O —T) kuusentaimien vuotui nen pituuskasvu B-kokeessa. Vaaka-akselilla taimien ikä kylvöstä lukien ja pystyakselilla latva kasvaimen pituus. Figure If). Annual height increment of spruce transplants stored by different methods and planted in different times (Experiment B). Abscissa = age of transplants from sowing, ordinate = length of the annual shoot. 34 Olavi Huuri 79.5 johtunee jälleen siitä, että myöhäisissä kesäistutuksissa (osakuvat Q— T) taimien latvakasvain on ennen istutusta taimitarhan suotuisissa olosuhteissa saavuttanut huomattavan suuren 13—17 cm:n pituuden. Ero on luonnolli sesti suuri, kun näiden taimien pituuskasvu toisena maastokasvukautena putoaa toisten käsittelyryhmien kasvun tasolle, 4—9 cm:iin. Vuotuisen kas vun tämän jälkeen tasaisesti parantuessa tapahtuu kehitys kaikkien käsit telyryhmien eloonjääneillä taimilla kuitenkin hyvin yhdenmukaisesti taimi tarhalla varastoitujen taimien (5) enää erottumatta toisten joukosta. 4. TULOSTEN TARKASTELUA Nyt suoritettu tutkimus on tuonut esiin taimien fysiologisen kunnon ensiarvoisen merkityksen istutuksen onnistumiselle. Tähän seikkaan on meillä kiinnittänyt huomiota ehkä eniten Yli-Vakkuri (1957, 1961) selvittäessään taimien suojelua noston ja istutuksen välisenä aikana. Metsän viljelyn suoritusketjun tässä osavaiheessa voikin piillä eräitä niistä syistä, jotka aiheuttavat epäonnistumisia viljelyssä, mutta joita on myöhemmin vaikea havaita ja osoittaa todellisiksi syiksi. Itse istutustyö suoritettiin tämän tutkimuksen kaikkien taimierien kohdalla mahdollisimman hyvin ja taimet hoidettiin myös mitä suu rimmalla huolella työn kaikissa vaiheissa. Siitä huolimatta kuolivat vahvat, koulitut kuusentaimet miltei kaikki toisen kasvukauden lop puun mennessä esim. kahta viikkoa pitemmän ojavedessä varastoinnin ja sitä erittäin suotuisana kevätkesän ajankohtana seuranneen istutuk sen jälkeen. Näyttää siis siltä, että paljon pelätty taimien ja niiden juurien kui vuminen ei ilmeisesti olekaan ainoa käytännön varastoinneissa taimien fysiologista kuntoa heikentävä tekijä. Taimien kunnon heikkenemiseen voi vat johtaa myös aivan päinvastaisetkin olosuhteet, liiallinen kosteus ja sen mukanaan tuomat vaarat, mm. kosteassa lämmössä viihtyvä, taimia hei kentävä mikroflora. Edelleen taimia heikentävät myös varastointipaikasta tai taimien tiheästä asennosta johtuva valaistuksen tai ilmanvaihdon riittämättömyys. Luonnollista myös on, että pitkä varastointi puolilämpimissä olosuhteissa ja pimeässä kuluttaa taimien vararavinnevarastoja ja siten heikentää nii den juurtumiskykyä, jonka on todettu riippuvan mm. taimiin varastoitu neiden tärkkelyksen ja sokereiden runsaudesta (esim. Curtis ja Clark 1950, Kramer ja Kozlowski 1960 sekä Jones 1967). Milloin taimet varastoidaan valaistukseltaan riittämättömissä, mutta lämpötilal taan taimen elintoiminnat, mm. hengityksen käynnistävissä olosuhteissa, jollaiset vallitsevat esim. talouskellareissa, on luonnollista, että taimet ajan pitkään menettävät istutuskelpoisuuttaan. Kuitenkin vasta taimien eri osien ravinnepitoisuuksien toistuvat mittaukset voisivat selvästi kartoittaa näiden tekijöiden täyden merkityksen. 36 Olavi Huuri 79.5 Vesi varastoinneissa 3 ja 4 taimien latvaosat olivat koko varastointiajan ulkoilman luonnonmukaisissa olosuhteissa auringonsäteilyn ja ilmavirtojen vaikutuksen alaisina. Kuitenkin juuri nämä varastointimuodot olivat kaikis ta nyt kokeilluista kuusentaimille tuhoisimmat. Tämä johtunee eräästä sei - kasta, jonka tärkeyden herkkiin havaintoihin kyenneet metsämiehet ovat jo aikaisin intuitiivisesti havainneet juurten hapentarpeesta. Jo sangen var hain (esim. v. Carlowitz 1713 ja Mante u f f e 1 1874) on viitattu siihen, että tiivisrakenteinen maaperä vaatii juurten sijoittamista istutuk sessa aivan maan pintakerroksiin. Juurten hapentarve on ollut jo kauan myös tutkijoiden tiedossa ja sen merkitystä on korostettu mm. metsäpuiden fysiologiaa tutkivien tiedemiesten keskuudessa. Esim. puiden juurten veden otolle on aerobisten olosuhteiden todettu olevan tärkeänä edellytyksenä (Kramer ja Kozlowski 1960 ja Kozlowski 1964). O r 1 o v i n (1966) suorittamissa kuusentaimien vesityskokeissa juurien kasvu päättyi jo muutamia tunteja vesityksen alkamisesta, kun vedessä olevan hapen varasto oli käytetty loppuun. Jo kolmipäiväinen vesitys aiheutti melkein kaikkien kuusen kasvujuurien kuolemisen. Tämän tiedon pohjalta voidaan ymmärtää, miten tuhoisia pitkälliset vedessä varastoinnit taimille tässä kokeessa olivat ja miten suuria taimitappioita tällaiset varastointitavat käytännön työssä huomaamatta ovat ehkä aiheuttaneet. Näyttää myös siltä, että mikäli kuusentaimet ovat aktiivivaiheessaan (Sarvas 1972) eivätkä lepotilassaan, jolloin niitä voidaan varastoida pitkiäkin aikoja koneellisesti jäähdytetyissä kylmävarastoissa, ei auta ko vinkaan paljoa se, että niiden elintoimintoja pyritään pitämään mahdolli simman hitaina. Parempia tuloksia saadaan, jos taimien annetaan olla varas toinnin aikana mahdollisimman luonnonmukaisissa olosuhteissa ja niiden elintoimintojen annetaan tapahtua vapaina ja voimakkaina. Hyvä ilman vaihto ja auringon säteily taimien oksistoissa sekä juurien luonnolliset elin olosuhteet riittävän kosteassa, kuohkeassa ja ilmavassa maassa varastoinnin aikana näyttävät takaavan taimien parhaan kehityksen myös keskellä kesää suoritetun istutuksen jälkeen. Hyvin samantapaiseen tulokseen päätyi myös Arnb o r g (1959) kokeil lessaan männyntaimien fysiologisen kunnon merkitystä niiden taimitarha koulinnan onnistumiselle. Loppupäätelmissään hän kehoittaa antamaan tai mien seistä alkuperäisessä penkissään viivästyneeseenkin koulintaan saakka. Männyntaimien erikoisominaisuudet sekä männyn istutuksessa yleensä kysee seen tulevien uudistusalojen karuus, aukeus ja kuivuus aiheuttavat kuitenkin sen, että taimitarhaolosuhteissa saadut tulokset eivät ole ilman muuta sovel lettavissa männyntaimien maastoistutuksiin. Sen sijaan kuusen istutusajan kohdan vaikutusta kokeiltaessa on pohjoismaisissa oloissa saatu useallakin eri taholla siihen viittaavia tuloksia, että paljasjuuristen kuusentaimien istut taminen suoraan taimipenkistä onnistuu kasvukauden kaikkina ajankohtina (esim. Heikinheimo 1941, Mork 1950, Huss 1958 ja Brekken 1965). 5. TUTKIMUKSEN PÄÄTULOKSET Jos kuusentaimien varastoinnin suoritustavan käyttökelpoisuuden mitaksi valitaan sen ajan pituus, jonka varastointi saa vaikuttaa taimiin ilman että niiden kuolleisuus istutusta seuraavien viiden kasvukauden aikana ylittää 10 %:n rajan, sijoittuvat nyt kokeillut taimien varastointitavat seu raavaan järjestykseen parhaasta huonoimpaan luetellen: Luonnonmukaisimmat varastointitavat, varastointi taimipenkissä ja valeistutuksessa, joissa taimien latvat saivat olla vapaasti auringonsäteilyn, ulkoilman lämmön ja ilmavirtojen vaikutuksen alaisina sekä juuret mullan peittäminä, osoittautuivat parhaiksi kuusen taimien ollessa kyseessä. Ehdottomasti huonoimmiksi taas osoittautuivat varastointitavat, joissa taimien juuret olivat yhtämittaisesti pelkän veden peittäminä. Taimien varastointi juuret jatkuvasti luonnonveden peitossa oli niin tuhoisa varastoinnin suoritustapa, että se jo kolmen viikon pituisena aiheutti valtaosalle taimia kuoleman joko ensimmäisen tai toisen kenttäkasvukauden aikana. Taimien turmeltumisen merkkeinä kehittyivät näkyviin liian pitkäksi venytetyssä kellarivarastoinnissa uusien versojen kellastuminen ja juurien sekä taimien tyvioksien homehtuminen. Liian pitkässä vesi varastoinnissa taas juuret mustuivat ja aluksi hyvin kasvaneet taimien latvat veltostuivat ja lopulta ruskettuivat. Valeistutuksen haittoina todettiin taimien tiheästä asennosta johtuva alaoksien kellastuminen kellari varastoinnin tapaan sekä valeistutusmaan huomaamaton kuivuminen hellepäivien aikana. Kuusentaimien istuttaminen suoraan taimipenkistä pitkin kesää ver hopuuston alle taas onnistui kaikkina kokeessa kyseeseen tulevina kasvu kauden vaikeimpinakin aikoina niin hyvin, että se vakavasti viittaa mah dollisuuteen istuttaa Etelä-Suomen järvialueella kuusta paljain juurin läpi koko kasvukauden verhopuuston suojaan. Varasto Varastointiaika, jonka jälkeen taimien kuolleisuus ylittää 10 % 1. Taimipenkki . . . . . . . Edellämainittua varastointiajan 1 vaarallista ylärajaa ei kokeessa lainkaan kohdattu 2. Valeistutus Varastoinnin vaaraton kestoaika n. 5—6 viikkoa 3. Kellari . . . Vaaraton kestoaika korkeintaan 4 viikkoa 4. Kaivovesi . . . Vaaraton kestoaika korkeintaan 2 viikkoa 5. Ojavesi Vaaraton kestoaika korkeintaan 1 viikko 6. LÄHDELUETTELO Ahola, V. K. 1930. Taimitarha, sen valmistus, kunnossapito ja hoito. Kms. Tapion käsik. 20. Helsinki. —» — 1949. Metsänviljely. Suuri Metsäkirja I: 190—234. Porvoo —Helsinki. Anto la, A. & Leh to, J. 1969. Metsänistutus. Metsänviljely (toim. J. Lehto): 191—230. Arnb or g, T. 1959. Plantkondition oeh tillväxt. Norrl. Skogsv. Förb. Tidskr.: 22—32. Blomqvist, T. J. 1898. Metsänhoidollisista taimitarhoista ja viljelystöistä. Helsinki. Borg, A. 1948. Metsän kylvö ja istutus. 3. p., tark. ja korj. A. Tanttu. Helsinki. B r e kk e n, P. 1965. Study of planting season for 2 + 2 Spruce in W. Norway. Tidsskr. Skogbr. 73: 330—345. Burckhardt, H. 1893. Sähen und Pflanzen. Trier. C a r 1 o w i t z, H. C. von. 1713. Sylvicultura oeconomiea oder Hauswirtliehe Nachricht und Naturmässige Anweisung zur Wilden Baum-Zucht. Leipzig. Cotta, H. & Ber g, E. von. 1856. Anweisung zum Waldbau. 8. Aufl. Leipzig. Curtis, O. & Cla rk, O. 1950. An introduction to plant physiology. New York. Gayer, K. 1898. Waldbau. 4. Aufl. Berlin. Hannikainen, P. W. 1919. Metsänhoito-oppi metsän ystäville. 4. p. Helsinki. Heikinheimo, O. 1941. Metsänistutusmenetelmistä. Referat: Versuche mit waldbaulichen Pflanzmethoden. Comm. Inst. For. Fenn. 29.4. Hesm er, H. 1950. Die Technik der Fichtenkultur. Hannover. H eye r, C. 1893. Der Waldbau. 4. Aufl. Leipzig. Huss, E. 1958. Om höstplantering av tall och gran. Summary: Autumn planting of pine and spruce. Skogen 45: 450 —454. H u u r i, O. 1972. Istutuksen suoritustavan vaikutus männyn ja kuusen taimien alku kehitykseen. Summary: The effect of deviating planting techniques on initial development of seedlings of Scots pine and Norway spruce. Comm. Inst. For. Fenn. 75.6. Ilmatieteellinen Keskuslaitos Finnish Meteorological Office. 1965 ja 1967. Suomen meteorologinen vuosikirja 64: I—2, 1964 ja 66: I—2,1 2, 1966. The meteorological yearbook of Finland 64: I—2,1 —2, 1964 and 66: I—2, 1966. Jones, L. 1967. Studies of some factors affecting survival of woody plant seedlings. Dissert. Abstr. 28 B (6), University of Georgia. USA. Kavi 11 u, K. 1965. Metsänviljely. Tapion taskukirja 15. painos: 92—104. Helsinki. Kozlowski, T. T. 1964. Water metabolism in plants. New York, Evanston, London. Kramer, P. J. & Kozlowski, T. T. 1960. Physiology of trees. New York, Toronto, London. Lehto, J. & Si m o 1 i nn a, J. 1966. Metsäpuiden taimien kasvattaminen. Helsinki. Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 39 79.5 Manteu ffe 1, H. von. 1874. Dio Hügelpflanzung der Laub-und Nadelhölzer. Leipzig. M o rk, E. 1950. Planteforsok med gran (Picea abies) til forskjellige tider i vege tasjonsperioden. Summary: Planting experiments with spruce at different times during the growing season. Medd. norske Skogforsoksv. 11: 31 —77. O r 1 o v, A. J. 1966. Rost i ziznedejatelnost sosny, jeli i berjozy v uslovijah zatople nija kornevyh sistem (Männyn, kuusen ja koivun kasvu- ja elintoiminnat juu riston ollessa veden vallassa). Teoksessa: Vlijanie izbytotsnogo uvlaznenija potsv na produktivnost iesov (Maan liikakosteuden vaikutus metsien tuotok seen): 112—154. Moskva. P aa v one n, T. W. 1915. Ohjeita metsän kylvössä ja istutuksessa. Suomen mh yhd. Tapion kansankirj. 3 —4. Raulo, J. & H i n t t a 1 a. T. 1972. Taimilajien merkitsemisestä. Metsä ja Puu 89 (5): 31. Reuss, H. 1907. Forstliche Bestandesgründung. Berlin. Räsänen. P. K. 1970. Nostoajankohdan, pakkaustavan, varastointiajan pituuden ja kastelun vaikutuksesta männyn taimien kehitykseen. Summary: The effect of lifting date, packing, storing and watering on the field survival and growth of scots pine seedlings. Acta For. Fenn. 112. Räsänen, P. K., Koukkula, A. & Yli-Vakkuri, P. 1970. Pakkauksen, varastoimisen ja valeistutuksen vaikutus männyn taimien istutuskelpoisuuteen. Summary: The effect of packing, storing and heeling-in on the field survival and growth of Scotch pine seedlings. Silva Fenn. 4: 46—67. Sarvas, R. 1972. Investigations on the annual cycle of development of forest trees. Active period. Tiivistelmä: Tutkimuksia metsäpuiden kehityksen vuotuisesta sykluksesta. Aktiivi periodi. Comm. Inst. For. Fenn. 76.3. S tââ 1, E. 1964. Förvaring av plantor i vatten. Skogen 51 (4): 108. Yli-Vakkuri, P. 1957. Tutkimuksia taimien pakkauksesta ja kuljetuksesta. Summary: Investigations into the packing and transportation of plants. Comm. Inst. For. Fenn. 49. l. —»— 1961. Taimien suojelu noston ja istutuksen välisenä aikana. Kasvinsuoj. Seur. Julk. 21: 39—45. 7. SUMMARY The Effect of Field Storage Methods on Initial Development of Planted Spruce In the 1960's the Finnish Forest Research Institute investigated, by means of several field experiments, the importance of the various steps in planting operations to the overall reforestation results. In connection with this project it was also desirable to investigate the effect of the most common methods of intermediate storage close to the planting area on the initial development of the planted transplants. Therefore, a few field experiments for spruce and pine were established at Hartola in 1964—1966. The results for spruce will be reported here. The spruce experiments were conducted during two years in two locations. Both test areas are situated on fertile Oxalis-Myrtillus site types covered with a dense alder nurse crop (Figure 5). The plots are located about 600 meters apart in the Kalho village of the Hartola parish (N 61°29', E 25°58'). The soil is even fine sand and clay covered with a thick layer of mineral soil mixed with abundant humus. The experimental design was single randomized blocks. The treatments, which were combinations of storage method and planting time, were randomized on the blocks of the test areas. The transplants used were 2/2 Norway spruce (Picea abies (L.) Karst.), commonly used at that time. Time of lifting, storage, and planting are presented in Figure 2. Each plot had 5 transplants, and the whole experiment contained two test areas, two years, 4—5 methods of storage, 4—6 times of planting, 176 plots, and a total of 880 transplants. Temperature and rain sums during the year of planting for the two nearest climate stations in Mikkeli and Heinola are presented in Figure 4. The methods of storage were as follows: 1. Storage in a cellar. This was a common method of storage in the Finnish countryside during the time at which the experiment was performed. The opened bundles of transplants were stacked compactly into wooden boxes with the roots covered with wet moss. The boxes were kept at about 10° C and 85 % relative humidity in the almost complete darkness of the cellar. 2. Stored as heeled-in transplants, according to well-known and international practice. 3. Stored in the water of a ditch. Storage of transplants in the spring in a water-filled hole or ditch was becoming increasingly common at the time when the experiment was carried out, and therefore, the method was included in order to gain guidelines for field work. 4. Storage in well water. As a comparison with the previous method, the roots of the transplants were submerged in a tub of well water which was changed once a week. 5. Storage in the nursery bed. The transplants remained intact in the original nursery bed until time of planting. 79.5 Kenttävarastoinnin suoritustavan vaikutus kuusen taimien alkukehitykseen 41 The transplants were planted at the edge of a planting hole made into the center pateh with a planting hoe (SFI-hoe). In order to investigate the effect of each storage method in more detail, the planting was carried out at various times throughout the whole planting season. In addition to Figure 2, the times of planting and also the lengths of the storage times have been presented i.a. in Figures 6, 8, 10, 12, and 14. Data on survival and condition have been presented in the same figures. The appear ance of transplants stored by different methods is indicated by photographs in Figures 1, 5, 7, 9, 11, 13, and 15. Development of total height and annual variation in height growth are presented in Figures 16, 17, 18, and 19. The main results of the study were: Provided that the quality of a storage method is defined in terms of the length of time in storage causing no more than 10 % mortality of planted transplants within the five first growing seasons, the tested field storage methods are ranked (best to poorest) as follows: 1. The seedlings grow intact in the nursery beds until planted: The above-mentioned time limit was not achieved during the experiment. 2. Storage as heeled-in and well-irrigated transplants: Duration without detrimental effects 5—6 weeks. 3. Storage in cellar: Duration without detrimental effects, maximum 4 weeks. 4. Storage in clean well water: Roots continuously covered by water. Duration without detrimental effects, maximum 2 weeks. 5. The same but the roots in ditch water: Duration without detrimental effects, maximum 1 week. The most natural methods of storage, in the nursery bed and heeled-in, where the tops of the transplants were freely exposed to insolation, air temperatures and movements, and the roots were covered by soil, proved the best methods for spruce transplants. The poorest methods proved to be those where the roots were continuously covered by water. Storing the transplants continuously in natural water was such a detrimental storage method that already after three weeks the majority of the trans plants died during the first or second growing season. Storage in an ordinary country cellar preserved the spruce transplants in good condition for planting-out during those four weeks for which storing normally may occur in spring spruce planting. Signs of impaired condition developed during too long storage in the cellar as yellowing of new shoots and mould on the roots and basal branches. Too long storage in water, on the other hand, caused blackening of roots; the initially rapidly-growing shoots wilted and finally turned brown. Negative effects of heeling-in occurred as yellowing of the lower branches (as in cellar storage) due to density of transplants and unobserved drying out of the soil during hot days. On a site under a nurse crop planting-out of spruce transplants lifted directly from the nursery bed was so successful, during even the most difficult periods of the growing season, that it strongly indicates the possibility of planting bare-rooted spruce transplants under nurse crop during the whole growing season in the inland of southern Finland. Acknowledgements: The author wishes to express his sincere thanks to Mr. O. Virta for drawing the figures, and to Dr. M. Leikola and professor R. Sarvas for help in preparing the manuscript. UNEQUAL PROBABILITY SAMPLING BY DBH CUMULATOR JOUKO LAASASENAHO Seloste KOEPUIDEN VALINTA KUUTIOMÄÄRÄN SUMMAAJALLA HELSINKI 1973 ISBN 951-40-0084-6 Hei rinki 1974. Valtion painatuskeskus PREFACE The purpose of the paper is to describe with the aid of a theoretical review and some practical applications the usage of statistics for the problem of sample tree selection. In addition to a general sampling theory the paper deals with the systematic sampling from the cumulated measures of size for which a special device has been developed. I am greatly indebted to the Finnish Forestry Society for providing me with a grant to help the development of an original idea to the level of a practice prototype. At the suggestion of Professor Kullervo Kuusela my study was included in the working program of the Department. The manuscript was revised by Kullervo Kuusela and Professor Hannu Väliaho. In addition, the manuscript was read by or the topics discussed with Mr. Erkki Mikkola, Lie. Phil., Mr. Sakari Salminen, M.F., and Dr. Risto Seppälä. The translation into English was made by Mr. Yrjö Sih v o, M. A. The English text was checked by Mr. John Dero m e, B.Sc. I owe sincere thanks to all these persons Helsinki in October 1973 Jouko Laasasenaho CONTENTS 1. Introduction 5 2. Sampling theory 6 3. Sampling by DBH cumulator 10 31. Finnish experiments of the 3-P sampling 10 32. The principle behind the sampling 10 33. The principle of the cumulator 11 34. Information provided by the cumulator 12 4. Calculation of results 15 5. Conclusions 17 References 18 Seloste 19 1. INTRODUCTION In forestry, both practical and scientific, one must often have recourse to some method of sampling. Forest estimation for different purposes is usually performed by means of a multiphased sampling method. In Finland more timber is nowadays being sold on-the-stum as a result of a computer system (the so-called PMP-scheme) which was developed for mensuration of standing trees and for calculation of wages. The selection of sample trees in this system is an important phase in the work. There are two phases in stand measuring: counting of trees (preparation of a list-of-units) and measuring of sample trees. When counting the trees, the DBH of every tree which satisfies a prescribed size qualification is recorded (1 or 2-cm. inter val). As tem-diameter distribution is thus obtained. Generally this list is made up by tree species and by timber assortments (saw-timber, pulp wood, etc.). The choice of sample trees takes place either in conjunction with the counting of the trees or else after it. In the former case, the selection is most often made by means of systematic sampling. The sampling interval varies according to the stem-diameter distribution. Visits to sample trees may occur either during the preparation of the list-of-units of after it. In the latter case, the selection of sample trees is ordinarily made with the aid of a relascope from observation points located at regular intervals. The selection of sample trees is a theoretical sampling problem. Overall instructions cannot be given, because we have no previous knowledge about, for instance, the range of variance in the characteristics to be considered. Many applications have been derived in the U.S.A. (Schreuder, Sedransk, Ware & Hamilton 1971) from the sample tree selec tion method which was presented by Grosenbaugh (1965) pro bability proportional to prediction (the 3 P-sampling). In Finland this app roach has also given working models based on differing principles (S ep pälä 1971; Laasasenaho 1971). When looking for an adequate sample tree selection method it is very important to bear in one's mind the background theory. In the next section, before the technique of sampling with the Cumulator is presented, some points of sampling theory are touched upon to illustrate which factors influence the accuracy of the results when using the technique generally used in Finland. 2. SAMPLING THEORY Obtaining a certain precision as to the information about the total volume within a stand which is marked for cutting may be set as target for a sampling. Since we have a stem-diameter distribution and we are interested in the results by DBH-intervals, the DBH-classification forms a stratification in the frame of which the sampling can be carried out. Under practical conditions in Finland, the diameters at breast height and at 6 m.-height (to the nearest cm) and tree height (to the nearest m) of the sample trees are measured. Subsequently the volume for the tree can be obtained either from the Tables of Ilvessalo (1947) or by equations. This volume however, is not accurate the relative standard error of the prediction is about 5 per cent. If this error can be assumed to be fortuitous and to vary by single trees, which assumption might not always hold true, the »table error» which is herewith introduced can approximately be control led by means of the number of sample trees. The mean error formula shows that the relative »table error» in the mean of the sample trees amounts to The variance of the total volume stratified into DBH-classes is obtained from the formula: (2.1) ö_ = %, where * Vn n = number of sample trees. (2.2) V (YJ = ENh (Nh ~nh where h=l n h N h = number of trees in DBH-class h n h = number of sample trees in DBH-class h S h = standard deviation of volume in DBH-class h L = number of DBH-classes (9.6 Unequal Probability Sampling by DBH Cumulator 7 If the costs per sample tree are supposed to be a constant, although this is not always true under all conditions, we get as sampling amounts for the different DBH-classes according to the optimal allocation (Coch ran 1963, p. 97) The variance in the volumes analyzed by DBH-classes increases steeply as the diameters become greater. The variance in volume on a Finnish pine sample plot has been tested and found to approximate the mean volumes of the corresponding DBH-grades when using the 1-cm. classification and working with 1 cu.dm. as a unit. As a matter of fact, the proportion variance/ mean volume within a DBH-interval can be expected to be somewhat constant. On the basis of this knowledge a prediction can be made as to the proportional distribution of sample trees into the different DBH-classes. The directions which have been given for practical purposes about the number of sample trees needed to attain a certain precision are far from being exact. Using a rule-of-thumb is sometimes not efficient enough. By means of the observations and formulae which have been presented above the number of sample trees required for certain cases can be approximated. The accuracy of the volume is also dependent upon the range of DBH intervals. The wider the classes, the larger the variance within each class. The effect of classification upon the variance within the classes can be described, for instance, as follows. Suppose the volume equation f(D) which is based on the DBH only is known. For instance, the equation which has been used for spruce in the present paper (3.1) p. 11. The accurate volume of the tree j with a diameter D is On postulating that inside each class Eej = 0, both £, and f(D) are independent, the variance for the class is obtained from the formula The influence of the interval range upon the variance can be computed precisely enough by barring the factor Ee 2 . The differences of variance with different class width appear, in particular, to hold true. n - n N* S» (2.3) Uh ~ U ZN h S h h=l (2.4) Vi f{D)-\-Ej (2.5) D 2(V) = D 2 f-\-D 2 e = Ef 2—(Ef) 2 +Ee 2 , where E is short for expectation; f stands for f(D) 8 Jouko Laasasenaho 79.6 Table 1. Dependence of the variance and the displacement in expectation of the mean upon the interval width with a postulated rectangular distribution Taulukko 1. Varianssin ja keskiarvon riippuvuus luokkavälin laajuudesta tasajakaumaoletuksella In Table 1 the dependence of the variance upon the width of the inter val has been calculated by means of equation (3.1) with 1 and 2-cm. inter vals by postulating a rectangular distribution in each class. In addition, the Table shows the displacement of E(j) in comparison with the value of (3.1) at the centre of the class interval with the same arguments (interval width and rectangular distribution). It can be seen from the values of f(D) in Table how quickly the volume increases with an increasing DBH. Classification could perhaps be left out alltogether in order to obtain a better understanding of its signific ance as to the accuracy of the results. If the class width 1 cm is replaced by the 2-cm. grading, then the variance becomes quadruple. Of course, no immediate information can be obtained from these figures which would show how the final results are affected by the DBH-classification. If we can assume the total variance with the 1-cm. interval to be equal in each DBH-class to the value of f(D) for the same class as it actually D HD) D*f, dm 8 with the class width of luokkavälillä 1 cm 2 cm 1 difference ero E(f)—KD), dm 3 with the class width of luokkavälillä 1 cm 2 cm 3 1.48 0.15 0.62 0.47 0.03 0.13 5 5.91 0.85 3.48 2.63 0.05 0.19 7 14.7 2 2.68 10.88 8.20 0.O6 0.24 9 29.06 6.29 25.44 19.15 0.07 0.2 7 11 49.94 12.35 49.91 37.56 0.08 0.31 13 78.27 21.57 87.07 65.51 0.O9 0.34 15 114.85 34.59 139.59 105.00 0.09 0.37 17 160.38 52.03 209.88 157.85 0.10 0.4O 19 215.48 74.39 300.01 225.62 0.10 0.42 21 280.64 102.08 411.63 309.55 0.11 0.44 23 356.30 135.39 545.8 7 410.48 0.11 0.45 25 442.7 7 174.46 703.29 528.83 O.ll 0.46 27 540.29 219.25 883.83 664.58 O.ll 0.46 29 649.00 269.62 1 086.79 817.17 0.12 0.47 31 768.96 325.25 1 310.84 985.59 0.12 0.46 33 900.11 385.59 1 554.03 1 168.45 0.12 0.46 35 1 042.35 450.05 1 813.70 1 363.66 0.11 0.45 37 1 195.45 517.81 2 086.86 1 569.05 0.11 0.44 39 1 359.13 587.98 2 369.64 1 781.66 O.io 0.42 41 1 533.00 659.66 2 658.37 1 998.7 2 O.io 0.41 43 1 716.64 731.7 2 2 948.4 7 2 216.75 0.09 0.38 45 1 909.50 801.81 3 225.37 2 432.56 0.O9 0.36 79. G Unequal Probability Sampling by DBH Cumulator 9 2 166 X8 —73 proved to be in a test carried out by the author the total variance with the 2-cm. interval would be, in the case of the DBH-classes running over saw-timber size, more than doubled as compared to the 1-cm. interval. One can see from the formula on p. 6 that the variance in total volume is 2-fold. This emphasizes the significance of classification. For stems of greater size the effect of the DB H -classification is greatest. Accordingly, it would be desirable to use the 1-cm. classification for saw-timber sized trees their unit volume being greater if the 2-cm. classification has been applied to the pulp-wood size. Moreover, the need for a narrower grading is emphasized by the fact that the saw-timber section of a stem may change very quickly as the DBH is increasing. In order to calculate the volume using equations, the displacement of the mean can be eliminated by measuring the DBH of the sample trees to 1 mm. and the tree heights to the nearest dm. 3. SAMPLING BY DBH CUMULATOR 31. Finnish experiments of the 3-1* sampling In a colloquy concerning sampling arranged by the Department of Forest Mensuration and Management, University of Helsinki, in 1969, the author suggested that ratio and regression estimators could be used for volume calculation in the sample plots. The accuracy of the results on variable sample sizes has since been analyzed by means of computer simulations to which was applied different calculation and sample tree selection methods. Among other things, simple random sampling was compared to a random sampling from the cumulated sum of the basal areas without replacement. The results obtained in the latter manner were found to be more accurate when applying variable calculation methods. This theme was continued by Messrs. Kilkki and Pakkanen who tested the accuracy of a sampling by DBH arranged in an optimal manner the results for each DBH-class being calculated on the basis of the sample trees which belonged to this class. Such a sampling was found to give about the same accuracy as the one described above, although the results were not in all respects comparable. For practical reasons, however, the colloquy decided on systematic sampling by DBH for sample tree selection. The theme was re-actualized in 1971, when Seppälä presented a method for applying the 3-P sampling using a random number generator. On the intuition gained from these trials, the author designed a volume cumulator (Section 33) with which the sampling takes place as a systematic sampling from the cumulated sum of the volumes. This method of sampling has proved to be more efficient than, e.g., the 3-P sampling which takes place by trees (Schreuder, Sedransk, Ware & Hamilton 1971). The absence of an apparatus simple enough for field use has prevented it from being applied in practice. 32. The principle behind the sampling With the volume Cumulator, sampling is made as a systematic sampling on the basis of the cumulated sum of the estimated volumes of the trees. 79.6 Unequal Probability Sampling by DBH Cumulator 11 The size of the tree (X;), which in this case means the volume in dm 3 , is estimated with the aid of the DBH. The estimation may be done, for in stance, by means of the function calculated for spruce (L aa s asen ah o & S e vola 1971): The sample is taken without replacement and the probability for each stem becoming a sample tree is proportional to the volume estamate Xi of the tree. The sampling procedure will be as follows (cf. Sehr e u der, Se d ran s k, W are &Hara i 1 1 o n 1971, p. 105). 1. The sampling interval (in volume) is fixed: it is generally greater than any value of Xt . 2. A random number sis chosen so that o ! d .f. MS Ix ! F Geographical Between stands .... Within stand + error 1 27 261 3 181 —2 071 124 049 — 6 673 1 349 1 018 1 079 659 1 079 26 261 25 4 6.2 5* Total 289 127 230 —8 744 3 446 2 845 288 — The difference to test the corrected means of south and north . 1 107 1 1 107 44 28**^ South North Age of sample trees, years . . 53 45 Bark percentage of sample trees .. 14.0 19.0 Bark percentage at the age od 50 years . . . .. 14.1 18.7 79.7 On the properties of larch wood in Finland 19 The regression coefficient of age is —O.O 61 (Fi )2B = 14.45***) for the material from South Finland. In Siberian and European larch the proportion of bark seems to be higher than in Dahurian and Japanese larch. The differences are not statistically significant, however. 42. Percentage of heartwood The percentage of heartwood refers to the proportion of heartwood in the total volume of barkless wood. Heartwood was separated from sapwood solely by its darker colour (Fig. 9). 421. Variation within the stem of Siberian larch The variation of the percentage of heartwood in the longitudinal direction of the stem is explained best by an equation in which the sampling height and tree height are concurrently the independent variables. More than three-fourths of the disc-to-disc variation can be explained. The percentage of heartwood in Siberian larch is greatest at the bntt of the stem and then decreases evenly towards the top of the tree. There is more heartwood in all parts of the stem of large than of small trees (Fig. 10). 100 • Volume of green heartwood Percentage of heartwood = Total volume of green wood K." Sy.x, % y = 26.0 0. 37 sXj+ 1. 9 7X 2 0.00240 X-L 2 0.779 10.7 y = Percentage of heartwood at a certain height x t = Relative height in the stem, % x 2 = Stem height, m Sums of squares Source of variation d.f. and products Deviations from regression Гх» ay ...» (£xy)' Ux 3 d.f. MS J? Between species .... 3 10 918 158 142 — —- Between stands .... 29 118 835 —7 295 1 307 859 28 31 10.3 3*** Between stems -f error 297 — - 955 955 297 3 Total 329 129 753 —7 137 2 404 2 Oil 328 — The difference to test the corrected means of species — — — — 197 3 66 2.13 Larch Siberian European Dahurian Japanese Age of sample trees, years . . . 53 35 44 42 Bark percentage of sample trees . . . 14.0 15.0 12.7 12.7 Bark percentage at the age of 50 years . . . . .. 14.2 14.2 12.4 12.3 Pentti Hakkila and Arja Winter 79.7 20 Figure 9. Heartwood formation in Siberian larch. Kuva 9. Siperian lehtikuu sen sydänpuumuodostuma Figure 10. The longitudinal variation of the percentage of heartwood in 15-, 20- and '25-metre Siberian larch stems. Kuva 10. Siperian lehtikuusen sydänpuuprosentin vaihtelu puun pituussuunnassa 15-, 20- ja 25- metrisessä rungossa. 79.7 On the properties of larch wood in Finland 21 The variation pattern of the percentage of heartwood in the longitudi nai direction of the Siberian larch stem is different from that of Scots pine and lodgepole pine. In these two pine species the proportion of heartwood grows at first from the butt towards the top and does not begin to diminish until a relative height of 10—30 per cent (cf. Lappi-Seppälä 1952, Uus vaara 1973). The average percentage of heartwood in a stem can be estimated from a sample taken at breast height. The accuracy of the method is appreciable. 422. Variation between stems of Siberian larch The average percentage of heartwood in a Siberian larch stem was 47.8 and its standard deviation was 13.3 per cent units. Of the external tree characteristics, diameter measured at 6 m height explains the variation of heartwood percentage best. A higher degree of determination is achieved by means of an equation in which diameter at breast height and age are concurrently the independent variables. The proportion of heartwood increases with age. On the other hand, there seems to be more heartwood the faster the tree has reached a certain size. An example may be mentioned by way of comparison of the effect of age on the percentage of heartwood in Siberian larch in the USSR (Khutorschikov and Zorina 1971). The proportion of heartwood appears to have been greater than at the same age in the present study. II s Syx, % y = 0.858X t 0.929 3.5 y = Average percentage of heartwood in a stem x t = Percentage of heartwood at breast height K 2 Sy-X, % y = 27.1 + I.SSXJ 0.539 9.6 y = 58.4—1 365/xa + 51. lx 3/x 2 0.83 5 8.5 y = Percentage of heartwood in a stem x t = Diameter at 6 m height, cm x 2 = Age, years x 3 = Diameter at breast height, cm Dbh, cm Age, years 10 20 30 Heartwood, % 20 16 41 40 37 50 60 . . . 53 61 80 . 54 61 Age of sample trees, years 27 54 71 110 149 188 Percentage of heartwood . . .. 54 67 71 75 82 86 22 Pentti Hakkila and Arja Winter 79.7 423. Variation between stands of Siberian larch It is again possible to distinguish two components from the variation between stands, i.e. stand-to-stand variation and geographical variation. The differences between stands are higly significant. The age of the stand is an important source of variation. As was shown already by analysis of stem-to-stem variation the percentage of heartwood increases sharply with age. Variance analysis did not establish the differences in the heartwood per centage between South and North Finland to be significant. In analysis of covariance the age differences of the stands may also be considered but the difference proves even then to be insignificant statistically (F lj26 = 1.77). Average percentages of heartwood corrected by the regression coefficient of age, 0.4 6 (F 1;26 = 42.35***), are as follows. 424. Variation between larch species Analysis of variance based on the South-Finnish material shows again that the variation between stands is statistically highly significant. In con trast, no significant differences are observed between the species. The age variable is again in a decisive position. The coefficient of re gression for age, 0.475 (F 1)28 = 42.62***), given by covariance analysis may it 1 y = 23.4-J-0.460X! 0.620 y = Percentage of heartwood in a stand Xj = Age, years Source of variation d.f. ss MS Г Between south and north 1 3 616 3 616 2.31 Between stands 27 42 309 1 567 28.49*** Between stems + error 261 14 248 55 Total 289 60 173 208 South North Average age of sample trees 53 45 Percentage of heartwood in sample trees 48.7 40. s Percentage of heartwood at the age of 50 years 47.8 43.2 Source of variation d.f. ss MS F Between species 3 5 371 1 790 1.17 Between stands 29 44 415 1 532 31.27*** Between stems -f- error 297 16 029 49 Total 329 65 815 On the properties of larch wood in Finland 79.7 23 be used to correct the heartwood percentage of all tree species to correspond to an age of 50 years. Significant differences (F li2B = 3.3 7*) are then noted between the species. The percentage of heartwood in Japanese larch appears to be higher than that of other species. 43. Percentage of knotwood The percentage of knotwood indicates the proportion of actual knotwood in the total volume of the stem. The anatomically exceptional adjacent wood is not included. It should be noted that the basic density of knotwood is higher than that of defect-free stemwood and that the knotwood volume percentage is therefore always lower than the weight percentage. 431. Variation within the stem of Siberian larch Siberian larch is characterised by a large number of branches of rather thin diameter in the earlier stages of its development (Fig. 2). Some of the branches are later self-pruned, but the number of small knots within the stem remains great. The proportion of knot-free discs was smaller in this material than earlier in lodgepole pine. The number of branches is greatest in the lower parts of the tree. However, the butt-end branches die young and are self-pruned rapidly, so the volume percentage of knotwood is always smallest in the butt end of the stem. Branches are longlived higher up in the crown and grow thicker (cf. Uu s raara 1973). The longitudinal variation in the percentage of knotwood in Siberian larch can be seen in Fig. 11 which is based on 3 000 disc measurements and smoothed by eye. Regression analysis and other statistical methods were not applied because of the mode of collection of the material. 100 • Volume of green knots Percentage of knotwood = Total volume of green stemwood Larch Siberian European Dahurian Japanese Average age of sample trees 53 35 44 42 Percentage of heartwood in sample trees 48.7 39.1 52.4 58.3 Percentage of heartwood at the age of 50 years 46.9 45.5 54 e 61.6 Relative stem height, % Siberian larch Lodgepole pine Percentage of knot-free discs 1 52 50 10—30 41 64 40—60 43 62 70—90 63 75 Pentti Hakkila and Arja Winter 79.7 24 Figure 11. The longitudinal variation of the percentage of knotwood in Siberian larch. Kuva 11. Siperian lehtikuusen oksapuuprosenlin vaihtelu rungon pituussuunnassa. The percentage of knotwood in Siberian larch at the age of 50 years is equal to that in lodgepole pine at different stem heights. Knotwood seems to be a little more plentiful at least in the central parts of the stem compared with pine and spruce (cf. Nyli n d e r 1959). 432. Variation between stems of Siberian larch The average knotwood percentage of Siberian larch in the total material was 0.9 6. The variation observed in the sample trees was due largely to an analytical error, for 10—15 randomly selected discs are not enough to establish the percentage of knotwood in an individual tree. However, the effect of the growth rate on the proportion of knotwood is significant. K 2 Syx, °. y = 0.21+1. 0.091 0.74 y = Average percentage of knotwood in a stem Xj = Breast height diameter, cm x 2 = Age, years Relative stem height, % l 30 60 90 Percentage of knotwood Plantation-grown Scots pine 0.3 O.e 1.3 1.8 Plantation-grown Norway spruce 0.4 O.e 1.3 2. ■> Plantation-grown lodgepole pine 0.4 0.9 1.4 2.0 Plantation-grown Siberian larch 0.3 1.0 1.5 1.8 79.7 On the properties of larch wood in Finland 25 4 16617—73 Figure 12. Average percentage of knotwood in a Siberia larch stem as a function of breast height diameter and age. Kuva 12. Rungon keskimääräinen oksapuuprosentti Siperian lehtikuu sessa puun iän ja rinnankorkeusläpimitan funktiona. The value of the confidence symbols of the equation is small owing to the investigation method. However, Fig. 12 can be drawn to illustrate the interaction of tree size and age on the percentage of knotwood. 433. Variation between stands of Siberian larch A part of the stem-to-stem variation in the percentage of knotwood can be separated into stand-to-stand variation. Due to the mode of collecting the material, the standard deviation is again increased by analytical error. It is therefore possible to explain only a small part of the variation between stands. Of the individual variables, stand age explains the variation best. The proportion of knotwood decreases with the ageing of the stand. For instance, the percentage of knotwood is still 1.17 in a 20-year-old stand, R' y = 1.3 o—o.0 0. oo 6 7X t 0.1 50 y = Average percentage of knotwood in a stand x x = Age, years 26 Pentti Hakkila and Arja Winter 79.7 but only 0.7 6 in an 80-year-old stand. The age differences in the materials for South and North Finland must thus be considered in the study of geo graphical variation. It is again possible to use analysis of coveriance in which the age of the stand is the regression variable. The materials for South and North Finland are corrected to comparable age by means of the regression coefficient —0.007 (F lj26 = 4.38*). There is significantly less knotwood in the north, due at least partly to slow tree growth there. 434. Variation between larch species The comparison between larch species is again confined to South Finland. Age differences are taken into consideration in the analysis of covariance in which age is the regression variable. The regression coefficient for the age of the stand is —O.O 08 (F 1)28 4.4 3*). The proportion of knotwood seems to be considerably smaller in Japanese larch than in the other species. However, an attitude of reserve Source of variation d.f. Sums of squares and products Deviation from regression Z"x 1 2'xy •£y* v . (Xxy)' är d.f. MS Г Geographical ] 3 182 163 8 — — — Between stands .... 27 124 049 —836 39 33.5 26 1.29 2 7 ß*** Between stems + error 261 — — 122 121.6 261 0.4 7 Total 289 127 230 —673 169 165.5 288 — Difference to test the corrected means of south and north . . — — — — 10.4 1 10.4 8.08** South North Age of sample trees, years 53 45 Percentage of knotwood of sample trees 1.05 0. oo Percentage of knotwood at the age of 50 years 1.07 0.0 2 Source of variation Between species Between stands Between stadns +error d.f. 3 29 297 Sums of squares and products Гх, йу 10 919 — 45 118 835 — 997 zy 2 6.1 61.3 137.3 Deviation from osxy )« " ix* 52.9 137.3 regression d.f. MS F 28 1.89 4.09*** 297 0.46 Total 329 129 754 - -1 042 204.7 196.3 328 — The difference to test the means of species . — — — — 6.1 3 2.04 1.08 79.7 On the properties of larch wood in Finland 27 must be adopted to the difference for the material comprised only 20 Ja panese larches. The differences are not statistically significant. 44. Basic density The basic density indicates here the dry weight of unextracted wood in kilograms per solid cubic metre of green wood. Unless otherwise stated, the analyses of the within-stem variation represent knot-free wood. The stem and stand means, on the other hand, include the effect of knots. 441. Variation within the stem of Siberian larch The structure of Siberian larch is characterised by an abrupt transition from spring- to summerwood (Fig. 13). The wood density of such tree species decreases fairly sharply from the butt of the stem towards the top. The difference between the butt and the top of the merchantable part in defect free wood is 15 per cent (Fig. 14). When the effect of knots is taken into account the difference diminishes somewhat. Figure 13. An example of the radial variation in basic density of Siberian larch, based on microdensitometric analysis of a radiograph. Kuva 13. Esimerkki Siperian lehtikuusen säteensuuntaisesta puuaineen tiheyden vaihtelusta mikrodensitometrillä tulkitun röntgenkuvan pohjalta. Dry weight, kg .basic density = Green volume, cu.m Larch Siberian European Dahtirian Japanese Age of sample trees 53 35 44 42 Percentage of knotwood in sample trees l.os 1.31 1.07 0. eo Percentage of knotwood at the age of 50 years l.os 1.20 1.03 0. -T i Pentti Hakkila and Arja Winter 79.7 28 Figure 14. The longitudinal variation in basic density of defect-free wood in 15-, 20- and 25-metre Siberian larch stems. Kuva 14. Siperian lehtikuusen virheettömän puuaineen tiheyden vaihtelu puun pituussuunnassa 15-, 20- ja 25-metrisessä rungossa. The density of knotwood is always greater than the density of stemwood. Two equations are therefore presented for the longitudinal variation of wood density. The first represents solely defect-free wood while the other includes also the effect of knots. Stem height and the sampling height explain 30 per cent of the variation of the wood density in the disc material. If the random variation caused by knots is omitted and only defect-free wood is considered, the degree of determination rises to 40 per cent. The effect of knots on the density of a 20-m Siberian larch stem can be seen in the following figures. The effect is greatest in the upper parts of the stem. The density of Siberian larch is distinctly greater in all parts of the stem than the density of domestic softwoods. The density is lower than in birch, II s I s ? *' kg/cu.iii = 302.6+17 687/(x l + 100) + 2.386X 2 0.397 39.« y 2 = 317.5+15 664/(x 1 +100) + 2.663x 2 0.300 43.2 y 1 = Basic density of defect-free wood at a certain height, kg/cu.m y a = Basic density of wood at a certain height, including the effect of knot s, kg/cu.m x x = Relative height in the stem, % x 2 = Stem height, m Relative height in the stem, % Defect-free wood A11 wood Basic density, kg/cu.m Effect Kg/cu.m of knots % 1 525.4 525.8 0.4 0.1 10 511.1 513.1 2.0 0.4 30 486. 4 491.2 4. 8 1.0 50 468. a 475.1 6.9 1. 5 70 454.3 462.8 8.6 1.0 90 443.4 453.1 9. 7 2.2 79.7 On the properties of larch wood in Finland 29 Figure 15. The longitudinal variation in basic density of Siberian larch compared with some domestic species. Kuva 15. Siperian lehtikuusen puuaineen tiheyden vaihtelu rungon pituussuunnassa eräisiin kotimaisiin puulajeihin verrattuna. however, except for the butt. The longitudinal variation pattern resembles Scots pine most, though there is a considerable difference in level (Fig. 15). The investigation work can be speeded up if the average basic of the whole tree can be estimated from a single specimen. It is often simplest in practice to take an increment core sample from a living tree at breast height. The average density at breast height is 4 per cent more than in the tree as a whole. The error can be corrected with the regression equation. A sample taken at breast height explains 88 per cent of the variation of average tree density. An accuracy of ± 29 kg/solid cu.m is achieved with 95 per cent confidence. 442. Variation between stems of Siberian larch The stem-to-stem standard deviation of basic density is 40.4 kg/cu.m. Tree age explains the variation best. sy-*- kg/cu.m y = 62. 4+o. 8 3 7Xi 0.878 14.7 y = Average basic density of a stem, kg/cu.m Xj = Basic density at breast height, kg/cu.m T! 1 Sy '*' Ä kg/cu.m y = 539.4—2 057/xj 0.182 36.5 y = Average basic density of a stem, kg/eu.m Xj = Age, years Pentti Hakkila and Arja Winter 30 79.7 The effect of age on average stem density is considerable. To mention an example, the density of Siberian larch at the age of 30 years is 471 kg/ solid cu.m, but by 80 years it has already risen to 513 kg/cu.m. The degree of determination is poor, however, for density is influenced also by the growth rate (cf. Edlund 1966), genetic factors and other considerations. In the following table the density of Siberian larch, some other domestic tree species and plantation-grown lodgepole pine is compared. The range and standard deviation are generally greater in naturally regenerated stands than in plantations. The wood density of Siberian larch is thus appreciably higher than that of other softwoods growing in Finland. In agreement with earlier Russian investigation results, the density of larch wood approaches and sometimes even exceeds the density of birch (G ugn i n, Permi n o v, Buyn i t skaya and Abak i n a 1971). 443. Variation between stands of Siberian larch The stand-to-stand variation in density of Siberian larch is highly significant statistically. On the other hand, the differences between south and north are not significant. Stand-to-stand variation is explained primarily by the age of the stand. However, it is possible to explain only a fourth of the variation. E« y = 455.5 + 0.767 X! 0.257 y = Average basic density of a stand, kg/cu.m Xj = Mean age, years Snpcîps Mean age Basic density, kg/cu.m years Average s Hange s, % Pinns silvestris, naturally regenerated x ) 68 409 33 311—521 8.0 Pinus silvestris, plantation-grown 2 ) 42 395 28 7. l Picea abies, naturally regenerated x ) 78 387 30 308—482 7.8 Picea abies, plantation-grown 3 ) ... 43 352 21 6.0 Betula verrucosa, naturally regenerated 1 ) 57 497 31 407—571 6. 3 Betula pubescens, naturally regenerated x ) 54 482 29 397—561 6. l Alnus incana, naturally regenerated 4 23 361 22 281—412 6. 2 Pinus contorta, plantation-grown 5 ). 40 433 24 370—495 5. 5 Larix sibirica, plantation-grown . . . 53 492 40 351—600 8.1 References: 1 ) Hakkila 1966; 2 ) Uu u s V a a r a 1973; 3) Hakki 1 a and Uu us vaara 1968; 4) H a k k i 1 a 1970; 5 ) Hakkil 1 a and Panhelainen 1970. On the properties of larch wood in Finland 79.7 31 Nor are the differences between South and North Finland significant in covariance analysis which takes into account the age differences of the material (F 1)26 = 0.58). Corrected by the regression coefficient of age, 0.7 o (F l>26 = 8.49**), the values for the south and the north at the age of 50 years are as follows: Edlund (1966) found in Sweden that when the ring width remains unchanged the density of Siberian larch decreases from the south northwards and similarly when altitude from sea level grows. According to the present study deceleration of growth seems to compensate for this tendency so that density is in point of fact the same at a certain age in spite of the geographical location of the stand. 444. Variation between larch species The comparison of larch species is again confined to South Finland. The most reliable result is given by analysis of covariance in which age is the regression variable. Different larch species at the age of 50 years can be compared after the means have been corrected by the regression coefficient of age 0.7 67 (Fi, 28 = 9.71**). The density of Dahurian larch seems to be higher than that of other species, whereas the density of Japanese larch is distinctly the smallest. Edlund (1966) found that the basic density of Siberian larch was higher than that of European, Japanese or American larch (Larix ocddentalis). South North Average age of sample trees 53 45 Basic density of sample trees 494 485 Basic density at the age of 50 years 492 490 Source of variation d.f. Sums of squares and products Ä" -2.x y Deviations from regression / rvv \ä Zy' Zy'— d.f. MS F Between species .... Between stands .... Between stems + error 3 29 297 10 919 118 823 8 325 91 132 115 619 271 411 201 524 28 245 864 245 864 297 7 198 8.69*** 828 Total 329 129 754 99 457 623 894 556 659 328 The difference to test the means of species — 109 271 3 36 424 5.06** Larch Siberian European Dahurian Japanese Average age of sample trees 53 35 44 42 Basic density of sample trees 494 476 518 435 Basic density at the age of 50 years . .. . . 491 486 522 440 Pentti Hakkila and Arja Winter 32 79.7 45. Content of extractives The extractive content was measured in two ways. Hot water and acetone were used as solvents and both determinations were made from different samples. Hot water extraction separates from the dust samples mainly arabinogalactan and dihydroquercetin, while acetone extraction results in the separation of phenols, resin and a small amount of dihydro quercetin (B obr o v, Mutovina and Tyukavkina 1971 ). The extractive content is given in weight per cent. Because of laboratory capacity, the content of extractives was determined from only one sample per tree. It was therefore not possible to apply the same statistical methods as to other wood properties. 451. Acetone extractives The average content of acetone-soluble extractives in saw dust samples was 2.0 4 per cent. The standard deviation between samples was O.st per cent. The variation can be broken down into the following components. When the effect of tree size is eliminated partly, the standard deviation between stems in the investigation material is 0.6 6 per cent. However, geo graphical variation and analytical error are included in this, so the true stem-to-stem variation is smaller. The content of acetone-soluble extractives is greater for larch than spruce in South-Finnish conditions, but smaller than in pine (cf. Hakkila 1968). 100 • Dry weight of soluble matter Percentage of extractives = r Dry weight of unextracted wood Source of variation d.i. ss MS F Sampling height 13 603 407 46 416 13-2! ,3 = 10.53*** Larch species 3 446 812 148 937 V „1. ,3 = 33.7 7*** .Height class 3 59 496 19 832 3- 2 ! , з = 4.50** Interactions 78 494 887 6 345 7 8- 2 S 13 = 1-44* Stem-to-stem + error .... 293 1 309 674 4 410 Total 394 Acetone extractives О/ Scots pine pulpwood Norway spruce pulpwood Plantation-grown lodgepole pine Plantation-grown Siberian larch 3. 4 1.5 1.2 2.0 79.7 On the properties of larch wood in Finland 33 5 16617—73 Figure 16. The longitudinal variation of the amount of acetone ex tractives in Siberian larch when the average percentage of heartwood in the stem is 30, 50 or 70 per cent. Kuva 16. Asetoniin liukenevien uuteaineitten määrän vaihtelu Siperian lehtikuusessa puun pituussuunnassa, kun puun keskimääräinen sydän puuprosentti on 30, 50 tai 70. The content of acetone-soluble extractives decreased from the butt towards the top. It is a fourth smaller at the top of the merchantable part than at stump height. However, the random variation is considerable. The degree of determination is increased greatly when the percentage of heartwood in the stem is included as a second independent variable. When the heartwood content increases the amount of extractives also in creases (Fig. 16). 452. Hot water extractives The saw dust samples contained an average of 9.3 2 per cent of extractives soluble in hot water; this is considerably more than in any domestic tree species. According to Russian studies, the percentage of hot water-soluble extractives was 2—3 for Scots pine and only 1 for Norway spruce (K osa y a 1971, Gugnin, Permiko v, Buynitskaya and Abi kin a 1971). The comparable figures in a domestic study were 5.8 per cent for Scots pine and 4.3 per cent for Norway spruce (Nevalainen and Hosi a 1969). R 2 Sy-X, % y = 1.84 + 0.68/Xj 0.207 0.7 7 y = Percentage of acetone extractives at a certain height Xj = Relative height at the stem, % K 2 Sy-x, % y =1.48 + 0. 60/Xj + 0.00 44X 2 0.393 0.68 y = Percentage of acetone extractives at a certain height Xj = Relative height at the stem, % x 2 Percentage of heart wood in the stem Pentti Hakkila and Arja Winter 34 79.1 The standard deviation between samples was 3.2 4 per cent. The variation was broken down into components in variance analysis, and then the sampling height, the larch species and the height of the tree all proved to be statisti cally significant as sources of variation. On the other hand, interactions were not significant. Deviation between stems in which geographical variation and analytical error are again included is still 2.9 2 per cent when the effect of the height class (4 classes) has been eliminated. A part of the unexplained variation may be combined here with the variation in the percentage of heartwood, for the content of hot water extractives in heartwood is many times that in sapwood. The following examples illustrate Siberian larch. The longitudinal variation pattern of the extractives content in the stem follows the changes in the percentage of heartwood. The extractives content decreases from the butt towards the top. The degree of determination of the equation improves again when the average heartwood percentage of wood is taken into consideration (Fig. 17). The variable that represents tree size also increases the reliability of the equation, but still leaves con siderable unexplained variation. K 2 Sy.x. % y = 11.56 0.83 log Xx 0.162 2.96 y = 8.43 0.50 log X 1 + 0.048X 2 0.229 2.83 y =B. 1 8-(- 0. 0 7 2Xj 0.97 log X ! -{- 0.11 8X 2 0.21 BX3 0.354 2.62 y = Percentage of hot water extractives at a certain height X! = Relative height at the stem, % x 2 = Percentage of heartwood in the stem x 3 = Tree height, m Source of variation d.f. ss MS F Sampling height 13 80 450 6 188 F 13 7 9 л*** ' 2 9 3 — 1 .40 Larch species 3 10 320 3 440 F 3 , 2 9 3 = 4.03** Height class 3 11 774 3 925 F з , 2 9 3 = 4.60** Interactions 78 60 027 770 F 7 8 , 2 9 3 = 0. 90 Stem-to-stem + error .... 293 253 620 854 Total 394 Heartwood Sapwood Research material Hot water extractives, Reference % Natural forests, Irkutsk 16.4 2.2 Khutorschikov et ai. 1971 Natural forests, Irkutsk 12.9 5.0 Gugnin et al. 1971 Natural forests, Krosnoyarsk . 11.2 2.7 Gugnin et al. 1971 Plantation-grown, Sweden .... 16.8 2.4 Edlund 1966 Plantation-grown, Finland . . . 11.5 5.2 Nevalainen et ai. 1969 79.7 On the properties of larch wood in Finland 35 Figure 17. The longitudinal variation of the amount of hot water soluble extractives in Siberian larch when the average percentage of heartwood in the stem s 30, 50 or 70 per cent. Kuva 17. Kuumaan veteen liukenevien uuteaineitten määrän vaih telu Siperian lehtikuusessa puun pituussuunnassa , kun puun keski määräinen sydänpuuprosentti on 30, 50 tai 70. A special characteristic of larch wood is the exceptionally high content of water-soluble extractives. The main substance is arabinogalactan. Some Soviet investigation results for the average content of hot water extractives in larch wood are given here. The growing stock in these studies was older than that of the present work. The extractives content is therefore greater in every case than for Finnish plantations. Amount of hot water Species extractives in Reference wood, % Siberian larch 12—14 Khutorschikov et al. 1971 » 10—12 Chochieva et al. 1971 » 12—14 Korenevsky et al. 1971 » 12—14 Gugnin et al. 1971 Dahurian larch 9 Kosaya 1971 5. DISCUSSION The technical properties of larch wood and domestic softwoods differ in many respects. This causes difficulties when timber is used on an industrial scale, but the special characteristics of the wood also have certain advantages provided that they are properly exploited. Differences between tree species in southern Finnish conditions are presented in Table 2. It should be noted that for pine and spruce the question involves pulpwood made from naturally regenerated forests, while lodgepole pine represents 40-year and Siberian larch 50-year-old plantations. Larch seems to contain a good deal of bark, heartwood and water-soluble extractives compared with other tree species, and its basic density is exceptionally high. According to some earlier studies, the fibre is perhaps slightly shorter than in pine but the difference is not great (F 1a m m and Be 11 a k 1957, Edlund 1966, Khutorschikov and Zorina 1971.) Table 2. Average properties of Siberian larch at the age of 50 years in southern Finland compared with plantation-grown lodgepole pine, Scots pine pulpwood and Norway spruce pulpwood Taulukko 2. Siperian lehtikuusipuun keskimääräisiä ominaisuuksia 50 vuoden iällä Etelä-Suomessa verrattuina Murrayn männyn viljelmiin sekä mänty- ja kuusipaperi puuhun Property Ominaisuus Siperian larch Siperian lehtikuusi Lodgepole pine Murrayn mänty Scots pine Mänty Norway spruce Kuusi Bark, % — Kuorta, % 14 10 11 1) 20 !) 0.7 2 ) 12 !) 25 1 l Heartwood, % — Sydänpuuta, % 48 18 Knotwood, % — Oksapuuta, % l.l 1.0 0.7 2) Basic density, kg/cu.m — Tiheys, kg/k-m 3 Acetone extractives, % — Asetoniuutteita, % 492 2.0 433 1.2 405 3) 3.3 s ) 385 3) 1.5 3 ) 1 4 ) Technology, 9; 3 ) Hak- Hot water extractives, % — Kuumavesi- uuttpita. % 9 Department te; 2) N y 1 i 3 4 ) References: 1 ) Unpublished material at the Finnish Forest Research Institul kila 1968; 4 ) Kos ay a 1971 of Forest n d e r 195 On the properties of larch wood in Finland 79.7 37 As the physical structure and chemical composition of Siberian larch and domestic softwoods differ, it behaves somewhat differently in the pulp and paper making process. The practical experience of the Soviet pulp and paper industry is limited to old virgin forests. In addition, exhaustive laboratory experiments have been conducted in Sweden and more recently especially in Finland for which the wood material has been collected from plantations. Larch wood, unlike Scots pine and Norway spruce, contains a large amount of water-soluble extractives consisting mainly of polysacharide arabinogalactan. This hampers the processing into pulp, making especially sulphite cooking difficult. Moreover, its high wood density makes it necessary to ensure that the chip particles are of even size. Some of the problems observed in the sulphite cooking of larch are due to the following reasons (Korenevsky and Nepenin 1971). High wood density impairs impregnation with the cooking solution and favours secondary processes developing inside the chip. The resins hamper impregnation. The water-soluble substances, mainly arabinogalactan, cause premature loss of sulphite acid stability, resulting in failure to complete the cooking process. Subtances of a phenolic nature also hamper the impregnation and delay the process of sulphonation, because phenols participate in the condensation re actions with wood lignin. Certain difficulties are thus encountered in the sulphite cooking of larch wood. The best results are achieved in the bisulphite or two-stage process, but even then the pulp yield is lower than for pine and spruce (Edlund 1966, Nevalainen and Hos i a 1969, Korenevsky and Nepenin 1971, Saukkonen 1971). The difference in yield is as much as 5—7 per cent units (Saukkonen 1971). Larch is clearly more suitable for the production of sulphate pulp. The most obvious differences from Scots pine and Norway spruce sulphate pulps are higher consumption of alkali, lower yield, lower brightness, poorer tensile and burst strengths and distinctly superior tear strength. Larch pulp thus represents a new type of sulphate pulp in Finnish conditions, one that is highly reminiscent of the southern pine kraft pulps in the United States (Nevalainen and Hos i a 1969). The tear strength exceeds that of pine pulp in southern Finland by one third. Unlike pine, the strength properties are the same even in the north (Saukkonen 1971). The yield of sulphate pulp from Siberian larch is 2 per cent units lower than that from Scots pine (Kos ay a 1971, Saukkonen 1971, Hakkila, Nikki and Paleni'us 1972). Due to its high density, however, larch is superior to the domestic softwoods as regards the consump tion of wood. While the average consumption of Scots pine wood at kappa number 35 is 4.7 solid cubic metres per a ton of pulp (moisture content 10 %), 38 Pentti Hakkila and Arja Winter 79.7 the consumption of larch wood is 4.1 solid cubic metres only (Hakkila, Nikki and Palenius 1972). The difference is thus 0.6 solid cubic metres or 13 per cent. In bleaching the only noteworthy difference from the sulphate pulp of pine results from the higher content of extractives in larch wood. This necessitates a stronger alkali stage (Nikki 1971.) Larch pulp is eminently suitable as raw material for paper qualities that require tear strength. Sack paj)er is an example. Larch pulp can be used also for high-quality printing papers by bleaching and mixing it with short fibred hardwoods (Hosia 1971.) As regards the strength of newsprint, a 15 per cent addition of larch sulphate pulp equals a2O per cent addition of pine sulphate pulp. Raising the proportion of mechanical pulp, on the other hand, improves the optical properties of newsprint (Saukkonen and Arvela 1973). 6. SUMMARY Larch thrives relatively well in Finnish conditions. In experimental plantations the best results have been achieved with Siberian larch which has a natural range reaching in the west close to the eastern border of Fin land (Fig. 1). Before large-scale cultivation of an exotic is attempted, its suitability as industrial raw material must be known. To this end a study was begun in summer 1970 by the Finnish Forest Research Institute in cooperation with the Finnish Pulp and Paper Reseacrh Institute. Its aim was to examine the suitability of Finnish-grown larch wood as a raw material for sulphate pulp production. This paper concentrates on some wood properties that were studied by the Finnish Forest Research Institute. The investigation material comprised 40 plantations, seven of them in North Finland (Fig. 5). The main part of the material, 29 stands, grew Siberian larch (Larix sibirica). In addition, there were three European larch (Larix europaea), six Dahurian larch (Larix dahurica) and two Japanese larch (Larix leptolepis) stands in South Finland. The total number of sample trees felled was 400, 10 from each stand (Table 1). The mean age of the trees was 49 years. The percentage of bark by dry weight, the percentage of heartwood and knotwood by volume and the basic density of wood were determined from 5 cm thick discs which were sawn from the butt cross-section up to the top at intervals of 1 or 2 metres. In addition, the content of acetone- and hot water-soluble extractives was determined from the saw dust sample taken at a random height (Fig. 4). There were in all 4 500 discs and 400 saw dust samples. The percentage of bark in Siberian larch is relatively high, 15.5 on average. The deviation between stems was 3.7 per cent units. The proportion of bark decreased from the butt to 1/3 height of the stem and then began to increase again towards the top (Figs. 7 and 8). The tree size explained best the variation in bark percentage. As the tree grew, the proportion of bark decreased. Further, the faster the growth, the smaller was the proportion of bark. The bark percentage was considerably higher in North than South Finland. External characteristics explained 70 Pentti Hakkila and Arja Winter 40 79.7 per cent of the stem-to-stem variation and 35 per cent of the stand-to-stand variation. No significant differences were seen between the larch species. The percentage of heartwood is highest at the butt of the stem and then diminishes evenly towards the tree top. Heartwood was most plentiful in large-sized trees (Fig. 10). The average heartwood percentage of the Siberian larch stem was fairly high, 47.8, and its deviation was 13.3 per cent units. External characteristics explained 64 per cent of the stem-to-stem and 62 per cent of the stand-to stand variation. Diameter and age gave the best explanation. The proportion of heartwood grew with age. On the other hand, heartwood seemed to be the more abundant the faster the tree grew. No significant difference was established between South and North Finland. The percentage of heartwood in Japanese larch appeared to be higher than in the other larch species. The proportion of knotwood grew from the butt towards the top. It was 0.3 per cent at the butt of a Siberian larch stem, 1.8 per cent at its top (Fig. 11). The average percentage of knotwood was 1.0. Young and fast-growing trees contained the most knotwood (Fig. 12). The lower percentage of knotwood in North Finnish trees at a certain age is probably partly due to their slow growth. The differences between the larch species were not significant. The basic density decreased relatively sharply from the butt of the stem towards the top. The difference between the butt and the top of the mer chantable part of the stem was 15 per cent in defect-free wood (Fig. 14). When the effect of knots was taken into consideration, the difference de creased slightly. The average basic density of Siberian larch, 492 kg/cu.m, was considerably higher than that of domestic softwoods (Fig. 15). It was possible to explain only a little of the stem-to-stem variation, 40.4 kg/cu.m, by means of ex ternal charcteristics. The best single variable, age, explained 18 per cent of the stem-to-stem variation and 26 per cent of the variation between stands. No significant difference was established between South and North Finland. The density of Dahurian larch was higher and the density of Japanese larch was distinctly smaller than that of the other larches. The proportion of acetone-soluble extractives averaged 2.0 per cent. The deviation between the samples was 0.9 per cent. The acetone-soluble ex tractives content was smaller in South Finnish conditions for larch than for pine, but greater than for spruce. The extractives content diminished from the butt towards the top (Fig. 16). Hot water-soluble extractives averaged 9.3 per cent, which is considerably more than in any domestic tree species. The variation between samples was 3.2 per cent. The longitudinal variation in the amount of hot water extractives in the stem followed the changes in the percentage of heartwood. 79.7 On the properties of larch wood in Finland 41 6 16617—73 The quantity of extractives thus decreased from the butt towards the top (Fig. 17). The technical properties of larchwood differ from domestic softwoods in many respects (Table 2). Larchwood therefore behaves slightly differently from the conventional raw material used in the production of pulp and paper in Finland. Water-soluble extractives cause difficulties especially in the sulphite process. The bisulphite or two-stage processes give the best result. In Finnish condistions, larchwood is above all a raw material of sulphate pulp. Characteristics of larch compared with pine are high consumption of alkali, lower yield, lower brightness, poorer tensile and burst strength, but distinctly superior tear strength. The yield of sulphate pulp in the cooking experiments conducted by the Finnish Pulp and Paper Research Institute was 2 per cent units lower from Siberian larch than from pine. However, larch was better as regards wood consumption because of its high basic density. The consumption of larch wood was only 4. l solid cu.m. per ton of chemical pulp (moisture content 10 per cent), 0.6 solid cu.m less than the consumption of pine. Sulphate pulp made of larch is eminently suitable as a raw material for paper qualities that require a high tear strength. The experiments at the Finnish Pulp and Paper Research Institute also disclosed that when larch sulphate pulp is substituted for pine sulphate pulp in newsprint, the relative proportion of pulp can be raised. The optical properties of the newsprint are improved at the same time. LITERATURE B o b r o v, A. 1., M u t ovin a, M. G., T y u k a v k i n a, N. A. 1971. Investigation of effect of extractives on bisulphite cooking of larch wood. Use of larch as raw material for pulp and paper industry. Leningrad. Chochieva, M. M., Antonowsky, S. D., N i kit i n N. I. 1971. A study on chemical composition and physico-chemical properties of water soluble substances in larch wood. Use of larch as raw material for pulp and paper industry. Leningrad. Flamm, E and B e 1 1 a k, F. 1957. Vergleich von Sulfatzellstoff avis Lärchen- und Kiefernholz. Österreichische Papierzeitung 63 (6). G u g n i n, Y. A., Permiko v, E. D., Bu y n i t s k a y a, M. I. and A b a k i n a, G. N. 1971. Sulphate unbleached and bleached larch for board and paper pro duction. Use of larch as raw material for pulp and paper industry. Leningrad. Hakkila, Pentti. 1961. Lehtikuusipuun käyttömahdollisuuksista. Suomen Puu talous 2. —» — 1966. Investigations on the basic density of Finnish pine, spruce and birch wood. Lyhennelmä: Tutkimuksia männyn, kuusen ja koivun puuaineen tiheydestä. Communicationes Instituti Forestalls Fenniae 61.5. —»— 1967. Yaihtelumalleja kuoren painosta ja painoprosentista. Summary: Variation patterns of bark percentage by weight. Communicationes Instituti Forestalls Fenniae 62.5. —»— 1968. Geographical variation of some properties of pine and spruce pulp wood in Finland. Lyhennelmä: Eräitten mänty- ja kuusipaperipuun ominaisuuksien maantieteellinen vaihtelu Suomessa. Communicationes Instituti Forestalls Fer) - niae 66.8. —»— 1970. Basic density, bark percentage and dry matter content of grey alder (A 1n u s inc a n a). Lyhennelmä: Harmaalepän puuaineen tiheys, kuori prosentti ja kuiva-ainesisältö. Communicationes Instituti Forestalls Fenniae 71.5. —»— and Uusvaara, Olli 1968. On the basic density of plantation-grown spruce. Lyhennelmä: Viljelykuusikoitten puuaineen tiheydestä. Communicationes In stituti Forestalls Fenniae 66.6. —»— and Panhelainen, Arja. 1970. On the wood properties of Pinus contorta in Finland. Lyhennelmä: Suomessa kasvatetun Pinus contortan puuaineen ominaisuuksista. Communicationes Instituti Forestalls Fenniae 73.1. —»— Nikki, Marjatta and Palen i u s, Ilpo. 1972. Suitability of larch as pulp wood for Finland. Lyhennelmä: Lehtikuusen soveltuvuus massateollisuuden raaka-aineeksi Suomessa. Paperi ja Puu Voi. 54.2: 41 —58. Heikinheimo, Olli. 1972. Raivola. Helsinki. H o s i a, M. 1971. Lehtikuusisulfaatin erikoisominaisuudet. Suomalais-neuvostoliitto lainen puukemian symposiumi. Leningrad. On the properties of larch wood in Finland 79.7 43 II v ess a 1 o. Lauri. 1923. Raivolan lehtikuusimetsä. Referat: Dor Lärchenwald bei Raivola. Communicationes Instituti Forestalls Fenniae 5. K h ut oi'sohiko v, E. S.. Zori n a. G. A. 1971. Studies on physical properties and analysis of Siberian larch wood. Use of larch as raw material for pulp and paper industry. Leningrad. Korenevs ky, V. F., Nepe n i n. Y. N. 1971. Cooking of far-easten larch with variable content of water soluble substances in laboratory and industrial con ditions. Use of larch as raw material for pulp and paper industry. Leningrad. Kosa y a, G. S. 1971. Larch wood as raw material in obtaining sulphate pulp for chemical processing. Use of larch as raw material for pulp and paper industry. Leningrad. Nevalainen, Kauko and Hos i a, Matti. 1969. The suitability of larch as fibre raw material. Part 11. Lyhennelmä: Lehtikuusen soveltuvuudesta kuitu raaka-aineeksi. Osa 11. Paperi ja Puu. Yol. 51 (6): 503 —510. Nikki, M. 1971. Lehtikuusimassan valkaisukokeita. Suomalais-neuvostoliittolainen puukemian symposiumi. Leningrad. Nylin d o r, Per. 1959. Synpunkter pâ produktionens kvalitet. Kungl. Skogshög skolan. Institutionen för virkeslära. Nr U2. P alenin s. I. 1971. Lehtikuusen iän ja kasvupaikan vaikutus massan saantoon ja laatuun. Suomalais-neuvostoliittolainen puukemian symposiumi. Leningrad. R i kkon e n, Pentti. 1971. Valmiin puutavaran mittaus. Tapion Taskukirja. 16th edition. Helsinki. Sarvas, Risto. 1964. Havupuut. Porvoo—Helsinki. Saiikk o n e n, M. 1971. Eri puolilla Suomea kasvaneen lehtikuusen sopivuus massan raaka-aineeksi. Oy Keskuslaboratorio Ab. Seloste 1068. Unpublished. —»— and Arvela, P. 1973. Puolivalkaistu lehtikuusisulfaattimassa sanomalehti paperin sellukomponenttina. Oy Keskuslaboratorio Ab. Seloste 1118. Un published. SCAN-C7: 62. 1962. Massan diklormetaaniuute. Scandinavian Pulp, Paper and Board Testing Committee. Tigerstedt, A. E. 1922. Mustilan kotikunnas I. Havupuut. Summary: Arboretum Mustila. Acta Eorestalia Fennica 24. Tigerstedt, P. M. A. 1970. Dendrologiska experiment pâ Arboretum Mustila. Föreningens för dendrologi och parkvärd ärsbok Lustgârden 1969—1970: 141 —174. Upsala. Turtiainen, Markku. 1969. Lehtikuusiko Lapin puulaji. Metsä ja Puu 4:6. Uusva a r a, Olli. 1973. Puun laatu viljelymänniköissä. Manuscript. Vuokila, Yrjö. 1960 a. Lehtikuusen kuutioimisyhtälöt ja -taulukot. Summary: Tree volume functions and tables for larch. Communicationes Instituti Forestalis Fenniae 51.10. »— 1960 b. Siperialaisten lehtikuusikoiden kehityksestä ja merkityksestä maamme metsätaloudessa. Summary: On development of Siberian larch stands and their importance to forestry in Finland. Communicationes Instituti Forestalls Fen niae 52.5. »— 1971. Lehtikuusen puuntuotantokyky ja kasvatusmahdollisuudet Suomessa. Suomalais-neuvostoliittolainen puukemian symposiumi. Leningrad. SUOMESSA KASVATETUN LEHTIKUUSIPUUN OMINAISUUKSISTA Lyhennelmä Lehtikuusi menestyy Suomen oloissa verraten hyvin. Parhaat tulokset on saa vutettu Siperian lehtikuusella, jonka luontainen levinneisyysalue etenee lännessä lähelle Suomen itärajaa (kuva 1). Ennen kuin ulkomaista puulajia voidaan ryhtyä viljelemään käytännön mitta kaavassa, sen soveltuvuus teollisuuden raaka-aineeksi on tunnettava. Tästä syystä pantiin kesällä 1970 Metsäntutkimuslaitoksen ja Oy Keskuslaboratorio Ab:n yhteis työnä alulle tutkimus, jonka tavoitteena on selvittää suomalaisen lehtikuusipuun soveltuvuus sulfaattimassan raaka-aineeksi. Käsillä olevassa julkaisussa keskitytään eräisiin puuaineen ominaisuuksiin, joiden tutkiminen 011 ollut Metsäntutkimuslaitoksen tehtävänä. Tutkimusaineisto sisälsi 40 istutusmetsikköä, joista 7 sijaitsi Pohjois-Suomessa (kuva 5). Aineiston pääosa, 29 metsikköä, oli Siperian lehtikuusta (Larix sibirica). Lisäksi aineisto sisälsi 3 Euroopan lehtikuusen (Larix europaea), 6 Daliurian lehtikuusen (Larix dahurica) ja 2 Japanin lehtikuusen (Larix leptolepis) metsikköä Etelä-Suomessa. Yhteensä kaadettiin 400 koepuuta, 10 kustakin metsiköstä (taulukko 1). Puitten keski-ikä oli 49 vuotta. Kuoren kuivapainoprosentti, sydänpuun ja oksapuun tilavuusprosentti sekä puu aineen tiheys määritettiin 5 cm:n paksuisista kiekoista, joita sahattiin tyvi leikkauk sesta lähtien latvaan saakka puun pituudesta riippuen 1 tai 2 metrin välein. Lisäksi määritettiin asetoniin ja kuumaan veteen liukenevien uutteitten määrä satunnaiselta korkeudelta otetusta purunäytteestä (kuva 4). Kiekkoja oli kaikkiaan 4 500 ja puru näytteitä 400 kappaletta. Siperian lehtikuusen kuoriprosentti on 50 vuoden iässä korkea, keskimäärin 15.5. Kuoren osuus laskee tyveltä rungon 1/3-korkeudelle ja alkaa sen jälkeen jälleen kasvaa latvaa kohti (kuvat 7 ja 8). Kuoriprosentin vaihtelua selittävät parhaiten puun kokoa kuvaavat muuttujat. Puun kasvaessa kuoren osuus vähenee. Edelleen, mitä nopeammin puu kasvaa, sitä pienempi on kuoren osuus. Kuoriprosentti on Pohjois-Suomessa huomattavasti kor keampi kuin etelässä. Ulkoiset tunnukset selittävät runkojen välisestä vaihtelusta 70 %. Lehtikuusilajien välillä ei todettu merkitseviä eroja. Sydänpuuprosentti on suurin rungon tyvessä ja pienenee tasaisesti puun latvaa kohti. Siperian lehtikuusessa keskimääräinen sydänpuuprosentti on 50 vuoden iässä 48. Ulkoiset tunnukset selittivät runkojen välisestä vaihtelusta 64 %. län ja puun koon mukana (kuva 10) sydänpuun osuus lisääntyy. Sydänpuuta näyttää olevan myös sitä enemmän, mitä nopeammin puu kasvaa. Etelä- ja Pohjois-Suomen välillä ei havaittu merkitsevää eroa. Japanin lehtikuusen sydänpuuprosentti näytti olevan kor keampi kuin muiden lehtikuusilajien. 79.7 On the properties of larch wood in Finland 45 Oksapuun osuus kasvaa rungossa latvaa kohti. Siperian lehtikuusirungon tyvessä se oli 0.3, latvassa 1.8 ja keskimäärin 1.0 % (kuva 11). Oksapuuta oli eniten nuorissa ja hyväkasvuisissa puissa (kuva 12). Pohjois-Suomen puiden alhaisempi oksapuuprosentti tietyssä iässä aiheutunee osittain puiden hitaasta kasvusta. Lehtikuusilajien väliset erot eivät osoittautuneet merkitseviksi. Puuaineen tiheys alenee rungon tyvestä latvaa kohti. Ero tyven ja käyttöosan latvan välillä on virheettömässä puuaineessa 15 % (kuva 14). Kun oksien vaikutus otetaan huomioon, ero pienenee. Siperian lehtikuusen puuaineen tiheys, 50 vuoden iällä 492 kg/k-m 3 , on huomatta vasti korkeampi kuin kotimaisten havupuiden (kuva 15). Runkojen välisestä hajon nasta, 40 kg/k-m 3 , voitiin ulkoisten tunnusten avulla selittää vain vähän. Paras yksittäinen muuttuja, ikä, selitti 18 % runkojen välisestä vaihtelusta. Etelä- ja Pohjois- Suomen välillä ei todettu merkitsevää eroa. Dahurian lehtikuusen tiheys osoittautui muita korkeammaksi, Japanin lehtikuusen taas selvästi muita pienemmäksi. Asetoniin liukenevien uuteaineiden osuus oli keskimäärin 2.0 %. Se on pienempi kuin männyllä mutta suurempi kuin kuusella. Uuteaineiden määrä vähenee tyvestä latvaa kohti (kuva 16). Kuumaan veteen liukenevia uuteaineita oli keskimäärin 9.3 % eli huomattavasti enemmän kuin missään kotimaisessa puulajissa. Rungon pituussuuntainen vaihtelu myötäilee sydänpuuprosentin muutoksia. Uuteaineiden määrä pienenee siten latvaa kohti (kuva 17). Lehtikuusipuun tekniset ominaisuudet poikkeavat monessa suhteessa kotimaisista havupuista (taulukko 2). Tästä syystä lehtikuusi käyttäytyy massaa ja paperia val mistettaessa jossain määrin erilailla kuin Suomen massateollisuuden tavanomainen raaka-aine. Vesiliukoiset uuteaineet aiheuttavat vaikeuksia erityisesti sulfiittiproses sissa. jossa parhaisiin tuloksiin johtavat bisulfiitti- ja kaksivaihemenetelmät. Lehtikuusipuu on Suomen oloissa ennen kaikkea sulfaattimassan raaka-aine. Mäntyyn verrattuna ovat lehtikuuselle ominaisia suuri alkalin kulutus, alhaisempi saanto, huonompi vaaleus, pienempi veto- ja puhkaisulujuus mutta oleellisesti parempi repäisylujuus. Keskuslaboratorion keittokokeissa sulfaattimassan saanto oli Siperian lehtikuusella 2 prosenttiyksikköä alhaisempi kuin männyllä. Korkean puuaineen tiheyden vuoksi lehtikuusi on kuitenkin kotimaisia havupuita edullisempi puun kulutuksen kannalta. Lehtikuusipuun kulutus oli vain 4. l kiintokuutiometriä sellutonnia (kosteuspitoisuus 10 %) kohti, mikä on 0.6 kiintokuutiometriä vähemmän kuin männyllä. Lehtikuusisulfaattimassa soveltuu erinomaisesti korkeata repäisyluj uutta vaativien paperien raaka-aineeksi. Keskuslaboratorion kokeissa todettiin myös, että kun mänty sellu korvataan sanomalehtipaperissa lehtikuusisellulla, voidaan hiokkeen suhteellista osuutta nostaa. Samalla sanomalehtipaperin optiset ominaisuudet paranevat.