The size and nature of damage to the topsoil caused by timber extraction and skidding during early thinning operations in spruce stands

The study concerns the impact of two harvesting technologies – one based on a traditional horse skidding and one using a small MultiFKS winch powered by chainsaw motor on the size and nature of damage to the surface soil layer. The study was conducted in a spruce stand where early thinning was carried out. The total share of soil disturbed during harvesting operations was not large accounting for 2.99% of the cutting area for horse skidding and 1.73% for skidding using a MultiFKS winch. The volume of damage to the topsoil was 8.38 m3/ha and 2.64 m3/ha, respectively. The likelihood of disturbances of the soil layer was 47% for horse skidding and 31% for skidding by means of a winch. Both technologies were character−ized by a similar, ca 5% likelihood of cutting of topsoil to a depth larger than 5 cm. For both technologies the likelihood of soil compaction was significantly lower than soil cutting