Impact assessment of log skidding on soil condition of skid roads during ground-based logging in a plantation forest in Istanbul, Turkey

Ground-based logging operation is potentially one of the major soil-disturbing activities that cause soil displacement, rutting depth and soil compaction. Thus, logging operations should be carefully planned considering the factors that influence soil disturbance. In this study, soil displacement and rutting on the skid roads caused by a farm tractor during a logging operation were investigated in maritime pine (Pinus pinaster) plantation forest of Istanbul, Turkey. After each tractor pass, field measurements were performed on the selected cross sections that were established at 15 m intervals along a designated skid road. Soil disturbance caused by both rubber-tires and skidded logs was considered in this study. It was found that the average volume of soil displacement was 0.060 m(2) m(-1) along skid road. It was also found that the rut depth on skid road became significant after 5th, 10th, 15th, 20th and 30th passes, reaching an average of 4.0, 7.2, 8.7, 9.8 and 10.5 cm, respectively. Results indicated that soil displacement and rut depth increased as the number of tractor passes increased.