Analytical Hierarchy Process of Land Potentiality for the Forest Roads Optimizing Path Tracing in terms of enviromental (Case Study; Seri Dallak Kheil)

Forest roads network in forestry plans have main and basic role in the forest management, conservation and recovery. In this research the ability of GIS and AHP in production of road-use map in Dallak kheil forest of Sari with an area of 1521.89 hectare (without villages in study area) was investigated.
In this study, for finding a suitable method for optimal routing forest roads and finding environmentally optimal variant of GIS and AHP technique was used. According to effective factors on road planning such as slope, slop direction, soil, geology, stock growth per hectare, hydrology, landscape and conserved species, a questionnaire was provided and then the idea of the experts about forest road planning and relative importance of factors was collected. The factors were weighted in Expert choice (EC) software via pair wise method.Then based on weights, the maps of mentioned factors were overlaid and land capability map with four classes of most unsuitable, unsuitable, suitable and most suitable was produced. Different variants of forest road were designed on land capability map using Arc GIS 9.3 software and divider method. Finally, the status of designed road network and existing road was compared using Backmund and nearest route method.
Findings: Analysis of effective factors in the design based on the road design profesionals and forest roads, showed that standard slope with 0.254 relative weight, have the highest points and the outlook with relative weight 0.052 has the lowest points.
Discussion and The result of the comparsion betwwen the existing network with five new variants in terms of environmental considerations indicated that the second variant is the best variant due to the passing of the most sutibel areas (19.7%) and unsutibel (21.5%) in compared to the existing road and other variants. Also The second variant whit 62/72 cover persentage in compared to other variants and existing roads in terms of environmental performance were selected as variants better. The Chi square test was used to compare the most suitable variant with existing road. Results showed that the designed road network was significantly better than that of existing road, regarding pass from suitable area.