Assessment of Soil Disturbance Caused by Forest Operations by Means of Portable Laser Scanner and Soil Physical Parameters

Forest operations can cause compaction and rutting, resulting in soil degradation processes. Soil damage is usually assessed through costly and time-consuming manual field measurements. The aim of this study is to investigate the impact of logging operations on soil using traditional ground surveys integrated with laser scanning data acquired by a terrestrial portable laser scanner (PLS). PLS provides an alternative to soil rut manual measurements. Two skid trails, that differed by the numbers of machine passes and slope were sampled. Data collection was performed before and after forest operations. The specific objectives were: (i) to assess soil compaction, (ii) to determine rutting by way of multi-temporal high-resolution digital terrain models (DTM) generated by PLS data. This is the first study to assess changes in soil volume via PLS. Significant logging impacts were detected using both investigation methods (i.e. physical parameters from traditional surveys and rutting from multi-temporal spatial analysis based on DTM). The PLS method provides a very high sampling density of the soil surface, permitting detailed spatial analysis of terrain changes. Moreover, the pre-processing cost for PLS generated DTM is low in comparison to the time needed for traditional survey based on manual field measurements. PLS may be a useful instrument for soil sampling in forest monitoring applications.