Use of terrestrial laser scanning to evaluate the spatial distribution of soil disturbance by skidding operations

Abstract

Abstract: We investigated the disturbance to the surface of a skid trail caused by removing cut timber from inside the forest to the roadside by dragging using terrestrial laser scanning technology. We scanned the study site prior to taking any action, after skidding and after implementing post-harvesting reinstatement to the surface of the skid trail. From the point cloud obtained, we derived an irregular point field. We generated a triangulated irregular network which we then interpolated into a raster digital terrain model with a resolution of 1cm. By comparing the digital terrain models, we analysed the influence of skidding the timber and the influence of post-harvesting reinstatement upon the surface of the skid trail. The surface of the skid trail was most significantly affected in the area where the harvested logs were extracted and stacked for hauling. In the centre section of the trail, where the logs were dragged by a tractor, quite deep tracks were created and the intensity of soil disturbance was comparable to the handling section. The lowest intensity of soil disturbance was found in the area where the skid trail met the roadside. The post-harvesting reinstatement of the working area resulted in levelling the surface of the skid trail and the deepest tracks were filled in. The post-harvesting reinstatement caused a 12% increase of the volume of ruts, a 49% decrease of the volume of mounds of soil and a 6% increase of total soil volume change.