During the mountain pine beetle epidemic over the last decade, the lodgepole pines located on gentle terrain are being depleted. Steeper areas are currently being harvested to mitigate the midterm shortfall in timber supply. Cable harvesting has traditionally been used on steep slopes, but other ground-based systems are more economical. To understand better the options for innovative harvesting systems suitable for steep terrain, a one-week study was conducted in January 2014 in southeastern British Columbia. A Tigercat 635D six-wheeled skidder working on both steep and gentle slopes was evaluated for productivity, cost, and system characteristics as an alternative to cable yarding systems.
On slopes averaging 38%, the extraction cost was about $9.07/m3 lower than the cost of cable yarding in similar stand conditions. More study of this type of skidder under various slope and felling conditions is needed. Furthermore, an exploration of different team configurations of skidder with loader-forwarders, combined with the option of building trails on very steep slopes, might help to identify the optimal ground-based alternative to cable yarding on steeper slopes.
