Handling editor: Dr. Wei-Yew Chang 
Received 30 June 2023. Revised 21 May 2024. Accepted 19 June 2024 
© The Author(s) 2024. Published by Oxford University Press on behalf of Institute of Chartered Foresters. 
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which 
permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. 
Forestry: An International Journal of Forest Research, 2024, 1–9
https://doi.org/10.1093/forestry/cpae037
Original Article
Economic evaluation of reopening a dormant tree 
improvement programme: a case study with Scots pine 
in Scotland 
Vadim Saraev 1, *, Anssi Ahtikoski2, Richard Whittet 1, Duncan Ray1 
1Forest Research, Northern Research Station, Roslin, Midlothian, EH25 9SY, United Kingdom 
2Natural Resources Institute Finland (Luke), Tekniikankatu 1, FI-33720 Tampere, Finland 
*Corresponding author. Forest Research, Roslin, Midlothian, United Kingdom. E-mail: vadim.saraev@forestresearch.gov.uk 
Abstract 
The deployment of improved forest reproductive material (FRM) selected to yield greater timber volume and quality than unimproved 
material could help to maintain productive, sustainable, and resilient forests and increase resistance to abiotic and biotic threats under 
extreme climate change events. In Scotland, Scots pine (Pinus sylvestris L.) is a productive species that aligns with these objectives. 
However, confidence in Scots pine has been low in recent years due to damage caused by the needle blight Dothistroma septosporum. 
Recent provenance/progeny trials using native Scots pine material from the Caledonian pine woods indicate a favourable genetic 
correlation between growth and resistance to D. septosporum, suggesting that simultaneous improvements are possible. The Scots pine 
breeding programme in Scotland was closed in 2002. Here, we present an economic case for reopening the breeding programme to 
further improve Scots pine FRM. Specifically, we evaluate the costs and potential benefits of supporting a new programme. We conduct 
an analysis using three improvement scenarios using a Faustmann formula (amendedwith thinnings) tomaximize the land expectation 
value. Our results indicate that further improvement of Scots pine FRM would be cost-effective, outperforming the current Scots pine 
timber production and financial outcomes. The analysis shows that the Central scenario’s land expectation value rises by £883 ha−1 
compared to the baseline of £79 ha−1, assuming a 3.5% interest rate. We employed both annuity calculations and a break-even analysis 
to show improved FRM could maintain a breeding programme investment of £3.5 million per year over a 30-year period with a break-
even cost threshold increase of ∼52% for purchasing improved planting materials from £0.33 to £0.50 per seedling. In conclusion, the 
study provides economic evidence of the commercial benefits for reopening the Scots pine breeding programme to increase timber 
production and financial returns. 
Keywords: investment; optimal rotation; net present value; climate change; genetic gain; Scots pine; Pinus sylvestris L 
Introduction 
Deployment of improved forest reproductive material (FRM) is 
an important consideration for maintaining productivity, sustain-
ability, and resilience of planted forests under climate change 
(Archambeau et al. 2022, Ray et al. 2022). In Scotland, commercial 
forestry is dominated by conifers, which comprise 73% of the 
forest cover. Sitka spruce [Picea sitchensis (Bong.) Carr.] is the most 
important species, accounting for 61% of land under forest (Forest 
Research 2022a) and is typically managed under a clear-fell silvi-
cultural system,with nearly all plants deployed at restocking from 
an ongoing long-term genetic improvement programme. Scots 
pine (P. sylvestris L.) is the second-most important commercial 
conifer in terms of forest area (18%) and is particularly suited to 
sites in the North-East and East of Scotland, where the drier site 
conditions are less well suited to Sitka spruce, which is native 
to the moist oceanic region of the Pacific North-West of North 
America. 
In Britain, Scots pine benefitted fromamajor tree improvement 
programme in the second half of the 20th century, involving 
progeny testing of over 1000 candidates in more than 100 half-
sibling trials. After this round of progeny testing, breeding values 
for growth (height at year 10) and stem straightness (year 10) 
were estimated, to reselect a breeding population (Lee 2002). The 
breeding population was archived in clone banks, but no further 
breeding activity has taken place since that time. Improved FRM 
derived from the breeding programme is available from seed 
orchards, and accounts for ∼55% of 9–10 million seedlings sold 
annually in Scotland (Forest Research 2022b) were set up in the 
1970s and 1980s, which was before a complete set of breeding 
values were available and did not contain the best combinations 
of parents. Lee (1999) used index selection to show that predicted 
genetic gains from a seed orchard could be in the order of 14%– 
20% for height and 5%–19% for straightness, and so large increases 
in genetic gains are already available simply by establishing new 
orchards to replace or complement those established in the 1970s 
and 1980s. Nonetheless, additional improvement through further 
selection and testing may be justifiable if objectives have changed 
(e.g. new forestry objectives or emerging risks), if new information
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has become available that can be used by breeders, and most 
importantly, if a significant expansion of the resource is antici-
pated. Burton et al. (2022) argued that these conditions have been 
met in the case of Scots pine in Scotland. 
Burton et al. (2022) explored risks and opportunities for Scots 
pine improved FRM, in a stakeholder survey that identified dis-
ease, principally Dothistroma Needle Blight (DNB—Dothistroma 
septosporum), as the reason stakeholders had low confidence in 
planting Scots pine, considering this as a priority trait, in addition 
to the traditional volume and quality traits for improvement. New 
information was analysed from recently established provenance-
progeny trials using unselected maternal half-sibling progenies 
grouped by population from the native ‘Caledonian’ pine woods 
(Beaton et al. 2022). These recent trials were evaluated for a 
range of ecologically important traits and show genetic varia-
tion in response to DNB, which is favourably correlated with 
higher productivity. Material from these trials could act as a 
source of disease-tolerant infusion material or otherwise provide 
useful information to guide renewed breeding efforts (Burton 
et al. 2022). There are opportunities to expand the Scots pine 
resource, particularly in areas previously stocked with exotic 
species of pine (Corsican pine—Pinus nigra var. laricio; lodgepole 
pine—Pinus contorta) that have been decimated by DNB dam-
age. Given the dominance of Sitka spruce in Scotland, there 
is concern about production over-reliance, particularly in the 
climatically drier areas on sandy and loamy textured soils of 
North-East and East Scotland. The UK Climate Projections 2018 
(Murphy et al. 2019) indicate problems of increasing drought 
severity by the 2050s and beyond. While Scots pine is unlikely 
to yield as much as Sitka spruce in terms of biomass, there is 
evidence to show that, under drier climatic conditions, Scots pine 
may be more tolerant and resilient to drought and therefore 
suffer fewer drought-induced stem defects (Davies et al. 2020, 
Ovenden et al. 2022) compared to spruce, and so could be a 
more reliable option for sawlog production (Haapanen et al. 2016, 
Laverdière et al. 2022). 
To date, Scots pine improvement programmes in Scandinavia 
have resulted in genetic gains of ∼8%–25% in volume growth 
versus unimproved stock for Scots pine (for a concise summary, 
see Jansson et al. 2017, Table 1, pp. 275–276). Values of 14.5% and 
33.5% improvement for first- and 1.5-generation seed orchards, 
respectively, have been reported for Finland (Haapanen et al. 
2016). We consider that the growth conditions in Fennoscandia 
and in Scotland are similar with respect to factors, such as accu-
mulated temperature and precipitation. Earlier review papers 
(Mullin et al. 2011, Ruotsalainen 2014) also indicate that for Scots 
pine a 10% improvement in the whole rotation volume production 
in northern Europe is reported for the current generation of 
seed orchards. For Norway spruce (Picea abies) and silver birch 
(Betula pendula), the corresponding genetic gains range from 5% 
to 29% (Jansson et al. 2017). In France, realized gains at young 
ages (first-generation Scots pine seed orchards) are expected to 
be ∼7% (Bastien et al. 2017). Further, in France, the precipitation 
rates differ from those in Fennoscandia and Scotland. Drought 
is a limiting factor for pine growth in France, while in Scotland 
and Fennoscandia other factors are more relevant, thus implying 
that achievable genetic gains might diverge between France and 
Fennoscandia and Scotland. 
In Britain, we have predicted breeding values based on progeny 
tests for height and straightness but have not performed realized 
gain trials to understand how these values interact and impact 
on rotation volume at stand scale (Lee 1999). In general, for 
Scots pine, up to 20% higher early volume growth (compared to 
unimproved FRM) has been shown for phenotypic seed orchard 
material in several countries in northern and central Europe 
(Ruotsalainen, 2014). With respect to monetary impact, Scots 
pine breeding programmes have resulted in substantial economic 
gains. For instance, in Finland, the bare land value, BLV (expressed 
in e ha−1), corresponding to improved Scots pine FRM was ∼350% 
compared to BLV of unimproved FRM (Ahtikoski et al. 2020b). BLV 
is also known as land expectation value (LEV),which is the present 
value of an infinite number of net present values (NPV) from 
one rotation (Amacher et al. 2009). In addition, internal rates of 
return as high as 8.9% have been reported for improved Scots 
pine FRM (Simonsen et al. 2010). Overall, economic gains from 
improved Scots pine FRM tend to be lucrative for the landowner 
(Serrano-León et al. 2021), sawmills (Ahtikoski et al. 2018), and 
society through access to healthy productive forests (Ahtikoski 
and Pulkkinen 2003). 
The main objective of this study was to examine the economic 
case for reopening the Scots pine improvement programme based 
on the latest studies and knowledge of improved FRM. 
We address the objective using scenarios related to poten-
tial genetic gains in quantity, quality, and security (in the sense 
of a more stable timber supply due to increased resilience) of 
improved Scots pine. We apply the Faustmann optimal rotation 
length approach (Faustmann 1968, Amacher et al. 2009) amended  
with thinnings to maximize the LEV over an infinite time horizon. 
Twomethods are presented to investigatewhat the financial gains 
imply for the producers of improved Scots pine FRM (synonymous 
to the improved seedling providers or nursery producers), namely, 
an annuity approach and an equivalent planting material cost 
increase approach. 
Methods 
Data 
The financial analysis applied existing yield models developed by 
Forest Research (Matthews and Duckworth 2005). In particular, 
the model ‘M1’ for Scots pine yield class (YC) 10, planted at 2 m 
spacing (i.e. a stocking density of 2500 trees ha−1) was chosen 
since it is representative of the average value of productive Scots 
pine. In Britain, Scots pine YC ranges from YC4 to YC14 with a 
mean of YC10 (McLean 2019).Yield class is an index used in Britain 
to show the potential productivity of even-aged stands of trees. It 
is based on the maximum mean annual increment of cumulative 
timber volume achieved by a given tree species growing on a 
given site and managed according to a standard management 
prescription. It is measured in units of m3ha−1 year−1 (Edwards 
and Christie 1981).Hence, Scots pine YC10 implies amean volume 
increment of 10 m3ha−1 year−1 over the rotation. 
A survey of forest managers completed in 2007 (Macdonald 
et al. 2008) suggested that ∼80% of stands are thinned. Therefore, 
our study focuses on standsmanagedwith thinning interventions. 
The typical thinning schedule for Scots pine YC10 (Table 1) is  
derived from the standard management table schedule for Scots 
pine in Britain (Forestry Commission 2015) and from discussions 
with forest managers of Scots pine stands in Scotland. The first 
thinning typically occurs at a stand age of 29 years with 49m3ha−1 
removed. Subsequent thinnings occur at 7-year intervals, slowly 
decreasing in volume after the fifth thinning at the stand age 
of 57. 
The total area planted with Scots pine in Scotland is 150000 ha 
(Forest Research 2022a). The discount rate set out in the HM Trea-
sury Green Book (HM Treasury 2022) was applied and assumes a 
3.5% discount rate for projects of up to 30 years, declining in steps
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Dormant tree improvement programme | 3
Table 1. Thinning volumes for Scots pine YC10. 
Age (Y) 29 36 43 50 57 64 71 78 85 92 99 106 
Volume removed (m3/ha) 49 49 49 49 49 46.6 40.2 33.8 28.3 21.7 16.9 12.3 
thereafter. However, for this study and for simplicity, we assume 
a constant 3.5% discount rate. 
Costs 
The following attributes and costs are assumed for the eco-
nomic analysis and are based upon standard costs for productive 
conifers (according to rotation forestry with thinning and clearcut 
management): 
(1) Planting stocking densities: 2500 (trees ha−1) 
(2) Planting material costs: £0.33 per seedling, £825 ha−1 
(3) Forest establishment operations: site preparation and actual 
tree planting cost. Estimated at £850 ha−1 
(4) Establishment, maintenance, and management costs: 
fencing, replacing failed plants, spraying/weeding; general 
maintenance (including Forest Agent/Craftsperson, covering 
Years 1–5). Estimated at £670 ha−1 in terms of present value 
(assuming 3.5% discount rate). 
The average (re-)planting cost, taking account of all the 
operations, is £2345 ha−1, for which the planting material 
comprises ∼35% of the total cost. These data on costs are 
compiled from various sources based on the standard costs for 
woodland and forestry grants (Forestry Commission England 
2011, Scottish Forestry 2019, Forestry Commission 2021, Welsh 
Government 2021). 
The same cost was used for unimproved and improved planting 
stocks for two reasons. First, the focus of this study was to assess 
the extra cost of improved planting material to break even with 
the benefits of using the improved stock. Thus, the results show 
how much more can be paid for improved seedling material 
compared to unimproved seedling material to assess if the extra 
cost would remain financially viable. This analysis closely resem-
bles the analysis found in (Chang, Gaston et al. 2019a). Second, 
anecdotal evidence suggests that the price differential of planting 
improved versus unimproved material is currently small or even 
absent. 
Benefits 
For the study,we focus only on timber production, i.e. (discounted) 
timber revenues. These are calculated as a product of timber 
volume per ha and price per m3. Public benefits derived from 
other forest ecosystem services are not considered. It is important 
to keep in mind that timber value constitutes only ∼12% of the 
total annual value of woodland ecosystem services that besides 
timber also include carbon sequestration, air pollution removal, 
and recreation (ONS 2021). For forest owners, however, timber 
production and net revenues from it still play a crucial role 
(Juutinen et al. 2021). 
Timber prices 
Data on timber prices are taken from ‘Timber Price Indices’ (Forest 
Research 2022c), Table 2: Coniferous Standing Sales Price. Focus-
ing on the last eight bi-annual observations (30 September 2018 to 
31March 2022) leads to an average price of £33.50m−3 overbark (in 
2021 prices). This is the timber price adopted for the calculations 
here. A standing sales price approach is adopted, indicating that 
Table 2. Scenarios for gains from use of improved Scots pine. 
Scenarios Quantity Quality Security 
Low 5% 5% 5% 
Central 10% 10% 10% 
High 15% 15% 15% 
harvesting costs (cutting and haulage) are left out of the financial 
analysis. In other words, timber is valued as a standing sale (or at 
stumpage). 
Scenarios for improved Scots pine 
Scenarios were developed with expert input from the tree breed-
ing specialists (Table 2). 
A renewed Scots pine improvement programme would seek 
to make simultaneous gains in quantity and quality of wood 
produced per unit area, as well as the likelihood of harvesting 
and marketing it, this is largely influenced by the susceptibility 
to biotic and abiotic damage. In our simulations, we consider 
that improvements in each of these trait categories ultimately 
condense into higher productivity. Mechanical properties (e.g. 
wood density and stiffness), which are often strongly adversely 
correlated with growth, are not important limiting factors in Scots 
pine, and so improving quality is likely to involve selecting on 
variation in branching characteristics and stem sinuosity, the 
latter of which is only marginally adversely correlated with height 
in British Scots pine (Lee 2002). Reduced susceptibility to D. sep-
tosporum is associatedwith (or results in) improved growth (Burton 
et al. 2022). While we are aware of the growth-differentiation 
balance hypothesis (GDBH), which suggests that there would be 
a tradeoff between different traits, for instance, decay resistance 
and volumetric growth (Herms and Mattson 1992, Koricheva et al. 
1998), and the results of several studies seem to support the GDBH 
hypothesis (Swedjemark and Karlsson 2004, Oliva et al. 2010, 
Steffenrem et al. 2016). It is assumed that the overall gains from 
quite modest improvements of 5%–15% could be considered addi-
tive, with trade-offs being marginal or non-existent. For this case 
study, each of the improvements is assumed to have an equivalent 
impact on the total gain in production from improved SP, hence 
focusing entirely on equivalent impacts in terms of volume. The 
following multipliers are applied to the baseline volumes for the 
unimproved SP Scots pine: 1.15, 1.3, and 1.45 (described as low, 
central, and high improvement scenarios, respectively). 
Assumptions and approach 
Our economic analysis is based on a set of low, central and high 
scenarios (Table 2), whereby the low scenario represents a 5% 
improvement in quantity, quality, and security over unimproved 
material, the central scenario represents a 10% improvement, 
and the high scenario represents a 15% improvement. Quantity 
represents gains in timber volume. Quality represents gains in 
timber quality with a larger proportion of the felled timber assort-
ment qualifying as ‘green’ saw logs, e.g. due to improved stem 
straightness or reduced frequency and size of knots (Macdonald 
et al. 2009). Analysis of average prices disaggregated by timber
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product categories for the last 12 years for Scots pine showed 
that the difference in price between high (saw logs) and low 
(firewood orwoodfuel) values timber products is significant.High-
value products could be up to 3.65 times more valuable than 
low value products, with a mean difference in value of 2 times. 
Hence, there is a larger price premium for higher-quality timber 
products. Similar differences in value between high- and low-
quality timber products exist for Sitka spruce. Therefore, gains 
in quality can be quite important in an economic sense. For the 
standing sale, this gain could be accounted for by assuming a 
greater volume and improving the standing sale price. Security 
refers to the maintenance of timber supply from a more resilient 
forest reflecting the change to improved Scots pine becoming less 
susceptible to some abiotic and biotic threats. Given that abiotic 
and biotic damage generally reduces tree growth, we assume that 
these gains can also be added to the volume production. While 
unfavourable genetic correlations typically constrain simultane-
ous improvement of multiple traits [e.g. growth and mechanical 
properties (Zobel and van Buijtenen 1989)], greater breeding effort 
can help to identify correlation-breakers and overcome this lim-
itation (Klápsˇteˇ et al. 2022). Thus, the three scenarios considered 
(low, central, and high) reflect possible levels of effort placed in 
obtaining the benefits through research and development. 
Gains in the order of 5% are commonly available from first-
generation seed orchards following phenotypic mass selection 
without testing (Serrano-León et al. 2021). While testing has 
already taken place in Scots pine, we expect that at least 5% 
additional gains could be realized simply by using up-to-date 
information to define new seed orchards, or thin existing ones 
where appropriate. Such a programme would cost <∼£0.5 million 
over 10 years to establish 10 ha of seed orchards. The central 
scenario (10% additional gains) is an estimate of what may be 
achievable with additional progeny testing, including evaluation 
of new phenotypes prior to, or in parallel with the establishment 
of new orchards (assuming a cost in the order of ∼£5–10 million 
over 10 years). The high scenario (15% additional gains) represents 
a situation where improvement activities are carried out at a 
scale or level of precision sufficient to take forward individuals 
that overcome potential unfavourable genetic correlations, e.g. 
by deploying tested families or turning the current breeding 
generation over (assuming a cost in the order of ∼£10–20 million 
over 10 years). The central scenario is considered as the most 
probable outcome, while the spread between low and high 
scenarios indicates uncertainty in outcomes. These scenarios 
are compared to a typical current Scots pine stand—the baseline 
(unimproved Scots pine). Economic analysis results are reported 
in terms of the value per hectare (£ ha−1). 
Finally, we assume that improved FRM will be available in 
the required quantities, which may not always be the case. In 
reality, sometime may be needed to grow the required amount of 
improved FRM. However, the focus of the study is not the tran-
sition effects of planting more improved FRM but the economic 
analysis of the benefits of genetic gain at the scale of the Scots 
pine resource in Scotland and the case for reopening the domestic 
breeding programme. 
In this study, we focus on the LEV, the objective being to max-
imize the LEV through stand-level optimization. The Faustmann 
approach is a widely accepted way to analyse the economics of 
productive forest rotations and is adopted in this study (Ahtikoski 
et al. 2012, Saraev et al. 2017). The classical Faustmann formula 
(Faustmann 1849, 1968), also known as the LEV formula, ‘gives 
the present value of net revenues growing an infinite series of 
identical timber stands’ (Chang 2020). The optimum rotation 
length is estimated by maximising the associated value over an 
infinite series of identical rotations. A typical rotation would 
include planting the forest, waiting for it to grow, and then felling 
it for timber, but might also include other interventions such as 
regular thinnings throughout the rotation. 
For an exogeneous thinning schedule, the model can be 
adjusted to take thinning into account as follows (Coordes 2014), 
(1) is for LEV according to the Faustmann model with thinnings: 
LEV(T) = p f (T)e
−rT − c +∑K(T) i=1 p∗ g (ti) e−r ti 
1 − e−rt (1) 
where T is an optimal rotation length (the variable to be changed 
to maximize the LEV); p is the timber value (here valued at 
stumpage),p∗ is the value of thinnings, f (T) is a growth function for 
the timber volume at time T, r is a discount rate, and c is costs (e.g. 
due to planting and tending of a young stand). The last term in the 
numerator is the sum of thinning revenues occurring at times ti 
and volumes g(ti) given by the management tables; p∗ is typically 
lower than p to reflect the lower average tree size of thinnings 
and the costs. The total number of thinnings K(T) depends on the 
optimal rotation length, and potentially some other management 
rules, e.g. the rule of no thinning for a number of years after 
the establishment of the stand. Equation ( 1) is maximized to 
find the global optimum solution using a genetic algorithm (GA) 
implemented in R (Scrucca 2013, 2017), using the GA R package 
version 3.2.3 (R Core Team 2022). The use of a global optimisation 
is required because the LEV profile (see Fig. 2 below) is a non-
convex sawtooth-type function with multiple local maxima. The 
following settings for the GA were used: 
(1) Type: real-valued 
(2) Population size: 100 
(3) Number of generations: 500 
(4) Elitism: 5 
(5) Crossover probability: 0.8 
(6) Mutation probability: 0.1 
(7) Search domain: x1, lower =20, upper = 100 
(8) Iterations: 500 
The estimated LEV can be converted to an equivalent annuity 
payment (A) over a specified number of years if required for the 
purposes of economic analysis. This allows investment projects of 
different lengths to be compared. When the interest or discount 
rate (r) is constant,  (2) below yields an annuity payment (A) over 
N years: 
A = LEV 
1−(1+r)−N 
r 
. (2)  
Note that when N becomes infinite one is talking about perpe-
tuity payments, and in this case, A= r ∗ LEV. Finally, we assume 
that the gains from improved Scots pine (as estimated by the 
higher LEV relative to the baseline) are divided equally between 
the forest owners (who take decisions on planting, management, 
and harvesting) and the producers of the improved planting stock. 
Without a detailed study of the market structure, which is cur-
rently not available, one cannot confirm whether the forest own-
ers or the nursery producers have the greater bargaining power, 
and therefore, we consider a 50/50 split a fair assumption. In 
principle, one may also consider an extreme case where the forest 
owner is not economically disadvantaged and all the gains are 
appropriated by breeders and producers of the planting stock.This 
would strengthen the economic case for breeding and production 
of improved FRM.
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Dormant tree improvement programme | 5
Table 3. Optimal rotation lengths, LEV and volumes for baseline and scenarios. 
Scenario Improvement 
multiplier 
Optimal rotation 
length (years) 
LEV (£/ha) Stand volume 
(m3/ha) 
Thinnings volume 
(m3/ha) 
Base 1.00 48.7 78.7 266.1 98.0 
Low 1.15 48.7 520.4 306.0 112.7 
Central 1.30 48.7 962.2 345.8 127.4 
High 1.45 48.7 1403.9 385.6 142.1 
Figure 1. Growth curves for Scots pine yield class 10 and stand volume 
per ha: lower smooth line (No Thin)—stand volume with no thinning, 
top smooth line (Thin TotVol)—total thinned stand volume, which is the 
sum of the standing volume (sawtooth line, Thin), and cumulative 
volume of thinnings (lowest step like line) 
Results 
The growth curves for Scots pine YC10 for an unthinned stand 
(‘No Thin’, dark green line) and a stand thinned according to 
the management tables (‘Thin’, dark orange line) (Fig. 1) show  
how the timber volume of a main stand develops over time. For 
a thinned Scots pine stand volume (dark orange line), we also 
plotted the cumulative volume of thinnings (‘Thin CumSum’, dark 
blue line) and the total volume (‘Thin TotVol’, dark red line),which 
is the sum of thinned stand and volume removed by a thinning 
operation. At age 41, the total cumulative live volume of a thinned 
stand starts (dark red line) to exceed the volume of a non-thinning 
stand (dark green line). 
Table 3 below presents the modelled optimal rotation length, 
LEV,and volume for the baseline Scots pineYC10 and three growth 
improvement scenarios. 
As expected, the improved Scots pine models predict higher 
yielding volumes and LEVs. For the Central scenario, the LEV is 
12 times higher than the baseline LEV. As an example of the LEV 
profile and optimal solution (red dot) for the Central scenario, see 
Fig. 2. 
Differences versus the baseline for the estimated optimal rota-
tion length (stand age in years) were not significant ranging from 
−0.01 to −0.02 for low and high gain scenarios. This is due to 
two factors: first, the multiplier approach used for simulating 
the gains of improved FRM directly from the growth curve of 
unimproved FRM, and second, the fact that the gains are generally 
quite small. Together, these do not significantly change the shape 
of the growth curve to bring larger changes to the estimated 
optimal rotation length. Differences, i.e. gains, versus the baseline 
for the estimated LEVs are presented in Table 4. 
Figure 2. Typical LEV profile and the optimal rotation length (round dot 
mark), discount rate 3.5% 
Table 4. LEV gains from baseline versus scenarios for 
improved FRM. 
Scenario Difference in LEV (£/ha) 
Low 442 
Central 883 
High 1325 
Results for the Central scenario model show that the LEV per 
ha is £883 higher for the improved Scots pine than for the baseline 
unimproved LEV. 
Analysis of feasible investments into the 
improved FRM breeding programme 
As noted above, we assume the potential gains from improved 
FRM are split 50/50 between the forest owners and the producers 
of the planting material. We explore two approaches to investi-
gating what the gains for the producers of improved FRM imply. 
The first approach converts the gains in the LEV assumed to 
accrue to the producers (i.e. a half of the total gain from Table 4) 
into equivalent annuity payments over 30 years that could be 
used to undertake the investments necessary to produce the 
improved planting material and aid the reinstatement of the 
breeding programme. The second approach converts the gains in 
the LEV assumed to accrue to the producers into equivalent cost 
increases that the producers could charge to cover the expenses 
of the improved Scots pine material. 
Approach 1: annuity payments 
The equivalent annuity value to the producers of improved FRM 
according to half the LEV gain over a period of 30 years (Table 5) 
indicates that for the central scenario, an annuity of ∼£24 per ha
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Table 5. Annuity values over 30 years for different scenarios. 
Scenario Annuity_30 (£/ha/yr) 
Low 11.77 
Central 23.55 
High 35.32 
Table 6. Potential aggregate gains in LEVs and 30-year annuity 
values for producers of improved FRM in Scotland from the use 
of improved Scots pine. 
Scenario Gain in LEV (£) Annuity_30 (£/yr) 
Low 66255 244 1765 905 
Central 132 513 175 3531 882 
High 198 772 988 5297 909 
per year could be paid to the producers for 30 years to finance the 
investments required to run an improvement programme. 
The financial implications may be clearer by comparing the 
aggregate results for Scotland, assuming that either all the 
present Scots pine area will be used for the improved SP or that 
the total area of new planting using improved Scots pine instead 
of Sitka spruce will amount to a similar size (Table 6). 
The central scenario (Table 6), indicates the total gain in the 
LEV is ∼£132.5 million, and if half of this gain is converted to a 
30-year annuity, its value would be ∼£3.5 million per year. This 
could be the amount potentially available to the improved FRM 
producers in Scotland to fund the extra investment needed in 
an improvement programme for Scots pine over 30 years. If the 
programme of investments could be shorter, this will lead to a 
higher level of annual investments. For example, if it is agreed 
that 10 years of additional investments will be sufficient to kick-
start the improved FRM breeding programme, the annual finance 
available will increase to ∼£7.7 million. 
Approach 2: costs increases by producers of 
the improved FRM 
The alternative approach to exploring what could be done with 
the LEV gains due to improved Scots pine involves computing 
the potential planting material cost increase that could be fully 
financed by the gains. In this case, we assume the increased cost 
per seedling covers the cost of all genetic improvement (i.e. the 
nursery is also the breeder and seed producer). To be precise, 
the producer takes half (maintaining a 50/50 split assumption 
between the forest owners and the producers of the improved 
planting material) of the LEV gain from Table 4 to calculate an 
associated feasible total planting cost increase in LEV,making this 
gain zero. These cost increases could be paid to the producers 
of the planting material (seedling producers) for the improved 
planting stock, allowing them to increase their price per seedling 
accordingly. The results are presented in Table 7. 
The first column of Table 7 shows the new maximum level 
of total planting costs that would be feasible for the improved 
seedling producers to cover the increased LEVs (assuming that 
half the gains accrue to the seedling producers). The second 
column (Table 7) shows the feasible total cost increases compared 
to the baseline of £2345 ha−1. Assuming that these increases 
could be directed to the producers of the improved plant material, 
the percentage increase over the baseline planting material cost 
(£825) is given in the column three (Table 7). Finally, column four 
(Table 7) shows the new feasible price per seedling grown from 
improved FRM (assuming 2500 trees per ha), which could be 
compared with the baseline price of £0.33 per seedling. For the 
central scenario, e.g. over 51% increase in price per seedling could 
be afforded to break-even (costs equalling benefits of improved 
FRM for Scots pine). 
Discussion 
The examples of how investment in a Scots pine breeding pro-
gramme might be funded and how these two methods generate 
incentives for actors (producers and forest owners) to participate 
are clearly demonstrated in our analysis. The first approach, 
with annual investments into the sector and the improved 
FRM breeding programme, would require administration by a 
central agency or co-operative. The agency could be tasked with 
collecting an additional tax on profits from timber harvests 
(equivalent to half of the gains) to redistribute gains to those 
involved in improving FRM. The second approach, where the 
improved FRM producers could charge higher prices, would avoid 
administration costs. Both approaches rely on the sector under-
standing and accepting the economic analysis of the benefits of 
improved FRM. 
Our analyses show that ∼£3.5 million per annum could be 
allocated to a Scots pine improvement programme that would be 
financially viable, given the assumptions made in our scenarios 
(deployment area, genetic gains, etc.). Our rough estimates of 
the likely costs of realising the low, medium, and high (£0.05– 
£2 million per year for 10 years) gain scenarios fall comfortably 
within this range. An initial investment would need to be front-
loaded and have a long return horizon. 
It would be interesting and helpful to have data on the actual 
cost of a Scots pine breeding programme. Unfortunately, there 
is a lack of published evidence presenting such numbers, since 
the budgets of breeding programmes are rarely fully exposed 
in scientific papers. For instance, a recent review on economic 
evaluation of tree breeding (Chang et al. 2019b) does not reveal 
any budget related to national breeding programmes, but a more 
recent paper (Fugeray-Scarbel et al. 2023) provides some figures 
from which one can trace estimates on national breeding pro-
gramme costs. In France, the investment in breeding for maritime 
pine is on average 693000 euros annually. This value falls within 
the range of our rough estimate on the annual costs of reopening 
the Scots pine breeding programme in Scotland: from £0.05 to £2 
million, depending on the scenario applied (low, central, or high). 
Further, our analysis showed that ∼£3.5 million per annum could 
be allocated to a Scots pine breeding programme and it would still 
be financially viable, given the assumptions of the study (genetic 
gains, deployment area, etc.). 
The economic analysis explores what would be feasible under 
the assumption of a 50/50 split in the gains from improved Scots 
pine between the producers of the improved plants and the forest 
owners, and the analysis is based on the average case. There will 
always be variability among forest owners with respect to objec-
tives and silvicultural activity and a range in site productivity (as 
expressed by the YC),which influence the extent to which genetic 
gain can be realized. Other factors that must be considered are 
timber prices and discount or interest rates. Nevertheless, our 
analysis may serve as a useful starting point for discussions 
on possible solutions to enable more improved Scots pine to be 
produced and planted in Scotland.
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Dormant tree improvement programme | 7
Table 7. Alternative cost approach results estimating how much more could be charged per improved seedling (in percentage and 
absolute terms). 
Scenario New total costs, £/ha Cost increase compared 
to the baseline, £/ha 
Percentage increase in costs 
compared to baseline for 
planting material 
Feasible new cost per 
seedling (£0.33 baseline), £ 
Low 2590 245 29.7% 0.43 
Central 2771 426 51.6% 0.50 
High 2952 607 73.5% 0.57 
However, the economic feasibility does not address another 
crucial question: how willing would forest owners be to pay for 
the improved planting stock? This question still lacks a definitive 
answer. A recent paper on the subject stated: ‘ . . .  forest own-
ers value improved FRM (improved forest reproductive material) 
only moderately because of long lags between plantation and 
harvest . . . ’ (  Fugeray-Scarbel et al. 2023). In other words, forest 
owners may not be so willing to pay extra for improved FRM. On 
the other hand, a survey by (Tikkinen et al. 2021) indicated that 
forest owners—at least in Finland—are willing to pay more for 
the improved traits in FRM. Since the focus of this study was to 
evaluate and present positive economic evidence to restart the 
breeding programme in Scotland, the willingness to pay aspect 
was not addressed and may be the subject of future research. 
Plantations of genetically improved forest trees are critical to 
sustainable forest management (Jansson et al. 2017), and seed 
orchards are the most widely used delivery system to trans-
fer gains from tree breeding programmes to practical forestry 
(White et al. 2007). Ruotsalainen (2014) has concluded that forest 
tree breeding will become an integral part of successful bio-
economies because genetically improved trees can increase the 
supply of high-quality wood materials and the long-term prof-
itability for forestry. For instance, in Sweden, Rosvall (2011) esti-
mated that the economic gain from using genetically improved 
seedlings in Sweden would correspond to ∼14% of the value of 
the entire Swedish harvest in 2006. Similar encouraging results for 
Scots pine breeding have been reported in Finland (Ahtikoski and 
Pulkkinen 2003, Ahtikoski et al. 2020a), and in France and other 
countries (Serrano-León et al. 2021). However, justification of any 
breeding programme in economic terms is complex—since one 
needs to assess the financial incentives accruing to each relevant 
participant involved in deployment. In our study focusing on 
Scotland, the relevant participants are the forest owners, who are 
expected to accrue the benefits at rotation following additional 
investment up-front, and those involved in the development and 
deployment of improved material (i.e. breeders, seed, and seedling 
producers). To be able to re-launch an improvement programme 
for Scots pine, parties throughout the supply chain need to find 
financial incentives to participate in the programme, and our 
study provides these data. 
In view of the current lack of realized gain trials over a full rota-
tion, we rely on predicted breeding values for parents (Lee 2002), 
analysis of genetic variability in disease response in younger trials 
(Beaton et al. 2022), and expert knowledge. It is assumed for 
this economic analysis that all the quantity, quality, and security 
gains are additive and equivalent in each case to a corresponding 
increase in growth in terms of their impacts on the total timber 
harvest volume [cf. (Oliva et al. 2010, Steffenrem et al. 2016) for  
non-additivity, i.e. the growth-differentiation balance hypothesis 
(GDBH)]. The assumption of additivity implies that the overall 
effect of genetic gain might result in an overestimation in eco-
nomic terms. On the other hand, we applied a scenario analysis 
corresponding to a range of alternative assumptions on quantity, 
quality, and security—within that range, the additivity issue also 
plays a different role. Considering multiplicative effects for the 
scenarios leads to the following gains: 1.16, 1.33, and 1.52, which 
are not significantly different from the additive case used in this 
study. 
The models used in this case study were parameterized using 
the land area occupied by Scots pine in Scotland. Extension to the 
rest of Great Britain is valid due to the common national breeding 
zone for improved Scots pine and expected increase in demand 
for Scots pine planting stock in England, where exotic pine plan-
tations have suffered damage from Dothistroma needle blight (D. 
septosporum). Extending the use of improved Scots pine FRM from 
Scotland to the whole of Great Britain would further strengthen 
the economic case for re-starting the breeding programme. 
Finally, since stand-level optimization was applied in this study 
to maximize the LEV, a word of caution is warranted. In real-world 
forestry, forest owners seldomly (if ever) optimize the manage-
ment—rather they follow existing silvicultural guidelines, which 
are a compromise of financial performance, social and ecological 
sustainability, and climate aspects, an example of such guidelines 
for Finland is (Tapio and Ministry of Agriculture and Forestry of 
Finland 2023). Thus, one can argue that the calculated LEVs in 
this study correspond to more theoretical than practical financial 
values of Scots pine breeding in Scotland. 
Conclusion 
The economic sensitivity analysis demonstrated how further 
use of improved Scots pine forest reproductive material (FRM) 
could positively influence volume and net present values (LEVs) 
compared to unimproved or status-quo material. The annuity 
approach shows that improved FRM producers could be paid 
∼£24 ha−1 year−1 for 30 years to finance producing the improved 
plantingmaterial. The equivalent planting cost increase approach 
estimates that an increase of ∼£426 ha−1 in total planting 
costs could be afforded, equating to a 52% increase in planting 
improved material costs from the baseline of £0.33–£0.50 per 
seedling. 
Two potential funding approaches show how annual invest-
ments could be recovered, by a central agency or co-operative, 
or by planting material producers charging higher prices. The 
study provides evidence that there are no economic barriers for 
re-starting the breeding programme for improved Scots pine. Fur-
thermore, the economic case would be strengthened by extending 
the use of improved Scots pine FRM to the whole of Britain. 
Acknowledgements 
We are grateful to Elspeth Macdonald for comments on an earlier 
draft and for suggestions from reviewers of the article.
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8 | Saraev et al. 
Author contributions 
Vadim Saraev (Conceptualization, Formal analysis, Methodology, 
Project administration, Visualization, Writing—original draft, 
Writing—review & editing), Anssi Ahtikoski (Methodology, Writ-
ing—review & editing), Richard Whittet (Methodology, Writing— 
review & editing), and Duncan Ray (Methodology,Writing—review 
& editing) 
Conflict of interest 
None declared. 
Funding 
This study was funded by the European Project H2020 ‘Adaptive 
breeding for productive, sustainable and resilient forests under 
climate change’ (B4EST; grant agreement No. 773383) and the 
Forest Research Science and Innovation Strategy Core Program. 
Data availability 
The data underlying this article were derived from sources in 
the public domain references in the article. No new data were 
generated. 
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