Evaluation of the productivity and costs of excavator-based mechanized tree planting in Finland based on automated data collection

Abstract

The poor cost-effectiveness of mechanized planting (MECP) is the main reason for the low mechanization rate of planting. In this study, we investigated the productivity of the mechanized excavator-based planting of Norway spruce (Picea abies [L.] H. Karst.) seedlings based on data collected by the Risutec Asta documentation system. We also compared the costs of a MECP chain with two different manual planting (MAP) chains, where mounding was carried out by a crawler excavator (EXC) or a continuously advancing mounder (CONT). The MECP of seedlings was carried out using an EXC equipped with a Risutec PM-160 planting device. Generally, the nine study sites in western Finland contained few surface obstacles (e.g., the logging residues had mainly been harvested), which made the conditions very suitable for MECP. The average production time taken by the MECP was 9 h ha–1. The operating hour (G15-h) productivity averaged 215 seedlings G15-h−1, with the mean planting time being 13.8 s seedling−1. Loading 160 seedlings into the seedling cassette took approximately 10 min (3.8 s seedling−1). Overall, the cost of the MECP was about 3% lower than for the EXC + MAP. However, when productivity was set at <210 seedlings G15-h−1, the cost of the MECP was higher than that of the EXC + MAP. Based on our findings, the most cost-efficient planting chain was CONT + MAP. However, based on our results, the required level of productivity can be achieved if the sites are suitable for MECP and the machine operators are skilled.