Saturday, August 27, 2011
Following the tracks: Trails in harvest blocks
Beyond the forest road there may be trails made by logging equipment in the harvest area. Heavy cable harvesting or yarding machines are used to harvest large logs on the steep terrain of coastal BC. The trails into the harvest area are cable ways, so minimal disturbance of the soil occurs during harvesting. Logs are completely or partially elevated as they are moved by cable. Some slight soil scarification may occur, but it is usually beneficial for regenerating the next trees.
While cable logging is preferable to reduce soil disturbance, it is more costly. The machine in the photo has a high capital cost. Considerable effort is required to set up the machine before harvesting can commence. Guy lines have to anchor the machine and a loop of logging cables has to go around large pulley blocks at the distant edge of the harvest area.
In areas of BC with smaller timber and less challenging terrain, wheeled or tracked logging equipment traverses the harvest area to drag or carry logs to the road. Minor roads or skid trails are constructed within harvest areas for the equipment. Considerable soil disturbance and erosion can be caused particularly in the case of poorly planned skid trails on steep slopes. Soil disturbance can be reduce by better planning of trails, deactivating trails. Snow or frozen conditions may help to reduce soil disturbance on certain sites.
Logging machines of all types are heavy and powerful. While most equipment operators are skilled in manipulating their machines, BC has made little or no attempt to institute some form of trades certification and training. Training courses in soil and environmental conditions and in planning the harvest of an area would make operators more able to work with minimal impact on the environment.