Potential Soil Erosion following Skyline Yarding versus Tracked Skidding on Bladed Skid Trails in the Appalachian Region of Virginia

The majority of timber harvests on steep terrain in the Appalachian region use ground-based skidding with bladed skid trails. Skid trails commonly occupy approximately 10% of harvest sites and are potentially erosive areas. Cable yarding systems are less commonly used in the Appalachian region, yet they have been found in other regions to cause less erosion than ground-based skidding on steep terrain. The goal of this study was to compare potential soil erosion losses from cable yarding and conventional skidding with bladed trails in the steep Appalachian Plateau region. Potential soil erosion rates were evaluated on three timber harvests in which cable yarding and conventional skidding with bladed trails were used to harvest different areas within the same timber sale unit. Potential soil erosion rates were estimated with the universal soil loss equation as adapted for forestlands. Potential soil losses were estimated in a minimum of three sample locations for each yarder operational area (deck, yarder landing, spur road, corridor, and harvest) and each ground-based skidder harvest operational area (deck, skid trail, and harvest) on three sites. Areas in each harvest operational area were also determined. Overall, cable yarder operations had less potential erosion than skidder harvests (1.70 versus 1.86 tons/ac per year, respectively). Differences between cable and skidder operations would have been greater had not the poorly designed spur roads within the cable yarder operations yielded >25 tons/ac per year of potential erosion. Cable yarder operations could have been significantly improved with additional preharvest planning and better design of spur roads.