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

Abstract

The efficacy of the application of terrestrial laser scanning (TLS) technology to assess soil disturbances due to log skidding activities was tested in an evenaged forest stand (110 years old) in Slovakia. An area of 18 × 52 m along a skid trail was scanned with TLS before and after skidding operations, and after the post-harvesting reinstatement upon the surface of the skid trail. From the point clouds obtained by TLS, we generated a triangulated irregular network which was interpolated into a raster Digital Terrain Model (DTM) with a resolution of 1cm. By comparing DTMs before and after each of the above steps, changes in the soil surface due to log skidding and post-harvesting reinstatement were accurately quantified. The surface of the skid trail was most significantly affected in the area where logs were extracted and stacked for hauling. In the center section of the trail, where logs were dragged by a tractor, quite deep tracks were created and the intensity of soil disturbance was comparable with the handling section. The lowest intensity of soil disturbance was found in the area where the skid trail joins the roadside. The post-harvesting reinstatement caused a 12% increase in the volume of ruts, a 49% decrease in the volume of soil mounds and a 6% increase in total soil volume.