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조구현 ( Koo Hyun Cho ),조민재 ( Min Jae Cho ),한한섭 ( Han Sup Han ),한상균 ( Sang Kyun Han ),차두송 ( Du Song Cha ) 한국산림과학회 2015 한국산림과학회지 Vol.104 No.2
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 41,707 won/m3. The highest cost activity was the yarding phase which cost 20,083 won/m3 (48.2% of the total cost), followed by the costs of processing tree-length materials into marketable log lengths (12,143 won/m3; 29.1%), and then by the costs of sorting/piling the processed logs (5,039 won/m3; 12.1%). It was interesting to see that felling and processing trees at the stump had low costs at 1,315 won/m3 (3.2%) and 3,127 won/m3 (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.