Planning of optimum skid trails in order to reduce environmental damages in Shafaroud forest (Northern Iran)

Abstract

Harvesting and intervening in forest with regard to their capability and capacity is necessary in order to promote quality, quantity and breeding of forest stand. On the other hand, extraction of logs and their products is one of the most important operations in harvesting which is generally carried out by machinery along skid trail network. Therefore, determining skid trails and taking into consideration the related standards is necessary in order to reach harvesting objectives. GPS was used to survey skid trails and existing road network of Shafaroud Forest District number 3 and then a Map of skid trail network was prepared. The prepared Map covered 1059 hectares of Shafaroud Forest District Number 3. Then with the use of environmental factors and analyzing them the area was divided into suitable and unsuitable areas: Unsuitable areas are; areas with slope of more than 65%, soil susceptible to land slide, areas with ruined forest (volume less than100m3/ha), areas which contain Porotia, Diospirus and Pertrocaria species, areas with no trees, rural areas and valleys. Suitable areas are; areas with slope of less than 65%, areas with suitable soil, good drainage and suitable texture, areas that have volume of more than 100m3/ha, area which have Fagus and Carpinus species, etc. GIS Arc view/Arc info and etc were used to digitize and prepare related Maps and in order to find suitable areas and avoiding environmental damages the most suitable skid trails network were designed which covers 801ha of total area of district. Finally, the existing skid trails network Map was compared with the most suitable designed skid trails network. The results showed that 712 ha of the area that were covered by existing skid trails network were unsuitable areas for designing and constructing skid trails network and therefore causes environmental damages and also only 347 ha of the area that were covered by existing skid trails network were suitable areas. Meanwhile 454 ha of total District which were suitable areas, were not covered by the existing skid trails network. These areas were considered when designing the new skid trails network. The results of this research can be used in designing more appropriate skid trails with less environmental damages.