Investigation on The Damages to Residual Trees by Ground-Based Logging System (Case Study: Asalem-Nav Forest Area)

Logging damages to residual trees can reduce stand sustainability and bole quality. This study assessed the logging damage to trees following ground-based logging system in Asalem-Nav forest area. In this forest area, silviculture method is single selection cutting. After logging operation, field survey was done to collect data of residual stand damage. After exploitation, the condition of trees (species, dbh, safe, damaged or destroyed) and characterization of bole wounds (place, size and severity) were determined in 34 round shaped sample plots using systematic sampling method. The results showed that 13.2% of residual trees were damaged and 2.3% were destroyed. Most of the destroyed trees observed to be categorized in 10cm diameter class. Diameter class of 35 to 60 cm had more number of wounds, but wound sizes were larger in 65 to 90 cm diameter class. 72.5% of wounds were occurred ticker than bark. Most of the wounds were occurred on tree heights lower than 1 m. 21.7% of wounds were less than 10 cm2, 34.8% between 10-50 cm2, 30.4% between 50-200 cm2 and 13.1% more than 200 cm2. The wounds on the stump level occurred in small size and deep, but wounds on upper than 1 m in large size and superficial. The trees such as Acer and Alder had more damages. These damages caused by skidding operation. Designing and standard construction of skid trails based on selective logging method can be very useful to reduce logging damages to remaining trees in uneven aged forest.