Harvesting Cost of Tree-length Thinning in a Larix leptolepis Stands

Abstract

The purpose of study was to broaden our knowledge on the productivity and cost of thinning operations which has become increasingly practiced in Korea. The thinning operations were conducted in a 40-year old larch (Larix leptolepis) stand, including chainsaw felling and processing at the stump, followed by yarding tree-length logs using a Koller K301-4 tower yarder. The logs were further processed and sorted into 1.8 m and 3.6 m log piles at the landing. We used a standard time study method to evaluate key variables that affect the productivity of thinning operations. The total stump-to-pile operational cost was . The highest cost activity was the yarding phase which cost (48.2% of the total cost), followed by the costs of processing treelength materials into marketable log lengths (; 29.1%), and then by the costs of sorting/piling the processed logs (; 12.1%). It was interesting to see that felling and processing trees at the stump had low costs at (3.2%) and (7.5%), respectively. We used the detailed time study data to develop regression equations which were to predict yarding productivity. Our analysis showed that harvesting system cost was highly sensitive to the number of logs, yarding distance and lateral distance per turn, respectively.