Damages of Skidder and Animal Logging to Forest Soils and Natural Regeneration

Extracting logs from stump to landings causes extensive damages to forest stand and soil. In this research two parcels adjacent to each other were selected in order to assess the effect of traditional and mechanized methods of logging on regeneration and soil compaction. A skid trail and a mule trail with similar longitudinal slope, skidding direction and total volume of extracted wood were chosen in the parcels. The cylindrical sampling method was used to determine wet and dry soil bulk density and the samples were taken at 0-10 cm and 10-20 cm depth from skid and mule trails. The results showed that soil dry bulk density increase in skid and mule trails compared to control at 0-10 and 10-20 cm depth, was significant (p<0.01). This increase in mule trail at 0-10 cm depth was significantly higher than at 10-20 cm depth (p<0.01), but percentage of soil dry bulk density increase compared to control in skid trail at 0-10 cm and 10-20 cm depths was not significantly different. Soil dry bulk density increase compared to control at 0-10 cm depth of mule trail is higher than skid trail, but at 10-20 cm depth the skid trail is higher than mule trail. Systematic random sampling method was used to determine damages to different regeneration groups due to logging operations. The results showed that damages to each regeneration group seedling and small sapling in mule logging method were significantly lower than mechanized logging method.