Energy wood thinning as a part of stand management of Scots pine and Norway spruce

Abstract

The effects of combined production of industrial and energy wood on yield and harvesting incomes, as well as the feasibility of energy wood procurement, were studied. Data for 22 Scots pine (Pinus sylvestris L.) and 21 Norway spruce (Picea abies (L.) Karst.) juvenile stands in Central and Southern Finland were used to compare six combined production regimes to conventional industrial wood production. The study was based on simulations made by the MOTTI stand simulator, which produces growth predictions for alternative management regimes under various site and climatic conditions. The combined production regimes included precommercial thinning at 4–8 m dominant height to a density of 3000–4000 stems ha and energy wood harvesting at 8, 10 or 12 m dominant height. Combined production did not decrease the total yield of industrial wood during the rotation period. Differences in the mean annual increment (MAI) were small, and the rotation periods varied only slightly between the alternatives. Combined production regime can be feasible for a forest owner if the price of energy wood is 3–5 EUR m in pine stands, and 8–9 EUR m in spruce stands. Energy wood procurement was not economically viable at the current energy price (12 EUR MWh) without state subsidies. Without subsidies a 15 EUR MWh energy price would be needed. Our results imply that the combined production of industrial and energy wood could be a feasible stand management alternative.–1–3–3–1–1