Investigation of Damages to Stand Caused by Selection Cutting Using Skidding System in the Asalem-Nav Forest, Iran



Selection cutting using skidding system often causes physical damage to residual stand through felling and skidding resulting decline of bole quality and tree value. This research evaluated logging damage using skidding system on residual trees and stand regeneration in uneven aged hardwood forest of Asalem, were selection cutting was practiced. In this regard, systematic sampling method was used and also 30 round shaped sample plots with 1000m2 area were collected in parcel 238 (34 ha.) of district 2 Nav watershed. Characteristics of trees and stand regeneration (species, dbh, growing stage, safe, damaged and destroyed) and trees bole wounds (location, intensity and size) were measured in sample plots. Results showed cutting and extracting of 7.5 trees per hectare 14.1% of residual trees were damaged and 0.63% of those were destroyed. So, about 5.6 percent of stand regeneration were damaged and 8 percent were destroyed. Diameter at breast height in destroyed trees was lower than 22.5 cm and most of those observed in 10 cm diameter class. 29% of wounds were occurred on the crown area, 60% on the bole and 11% on the both crown and bole. More of wounds on the bole of trees were occurred with superficial intensity, size of >50 cm2 and lower than 1m from ground. Reforming of cutting, winching and skidding methods of signed trees can be reducing logging damages on remaining stand.