Evaluation of water soil erosion processes in forest areas in the Western Sudetes using terrestrial laser scanning and GIS tools

In the terms of forest soil protection function and the limitations of these functions resulting from forest works, the authors aim was to determine the intensity and spatial range of erosion, and the volume of soil material loss resulting by erosion processes and human activities. The remote sensing technique – terrestrial laser scanning (TLS) was used in the research of erosion processes occurring in the mountain forest on the surface of the skid trails. The measurements were performed with laser scanning resolution of 3×4 mm. Obtained points clouds have been interpolated to the digital terrain models 1 cm, which allowed evaluating the erosion phenomena using the method of differential models in the period of 2011–2013. In the study it was analysed the part of the skid trail (ca. 41 m2, ca. 35% average slope). It was determined that during the entire research period the amount of soil material loss was ca. 1.9 m3. The erosion processes occurred mainly in the form of sheet erosion with volume ca. 1.3 m3. The erosion processes in the form of sheet erosion occurred ca. 49% and 42% of trail section area, respectively. Results of the study indicate that it is efficient to use TLS for the monitoring of the erosion phenomena, qualitative and spatial range assessment. At the same time, it has been proven that intensive water erosion processes can also occur in forests