The fight against climatic change has introduced a new dimension to Finnish forestry. Renewable forest fuels play an important role in the national climate strategy, which is aimed at reducing the greenhouse gas emissions in accordance with Finland's international commitments. According to the Action Plan for Renewable Energy Sources, 5 million solid m3 forest chips or 0.9 Mtoe energy is to be derived annually from low-quality forest biomass by 2010: two thirds from logging residues from final fellings and one third from small trees from early thinnings.
The production of fuel chips from early thinnings is a challenge, but provides the opportunity to improve the tending of young forests. To make the use of chips competitive, the cost of harvesting must be reduced, and the yield of biomass per hectare must be increased. Therefore, in industrial operations the chips are produced from whole trees rather than delimbed stems. The intensive recovery of biomass can result in the accelerated loss of nutrients from forest soils, and this has to be taken into account in site selection and system development.
In 1999, the National Technology Agency Tekes launched a five-year Wood Energy Technology Program to develop efficient procurement systems for large-scale production of forest chips from residual forest biomass. The ongoing program is reviewed in this paper from the viewpoint of early thinnings. Among the topics discussed are the resource and its biomass composition, background problems, cost of production, silvicultural impacts, benefits from the program, and future prospects.
