Geometric thinning for forest bioenergy

Current Swedish forest management recommendations are intended to maximize production of stem wood and therefore young stands normally are pre-commercially thinned (PCT). If cost-efficient techniques for harvesting small whole trees (≤ 8-10 cm in diam. at breast height (DBH)) could be developed, costly PCT could be turned into an income and more bioenergy would be available. Results from studies of prototype equipment for geometric boom-corridor thinning between strip-roads (approximately 1 m wide and 10 m long corridors) show potential to at least double the productivity, compared to conventional harvesting operations. The goal was to demonstrate a boom tip mounted felling head for continuous felling and accumulation of trees in boom corridors. The accumulation capacity was good enough to handle all trees in most boom corridors. It was thus concluded that the first steps on developing a tailor-made harvesting technique for thinning of biofuel in young dense stands had been taken.