Planning road network in mountain forests using GIS and Analytic Hierarchical Process (AHP)

Forest road construction is the most costly operation in forestry. Road designing and construction in unsuitable areas may increase construction and maintenance costs and also cause many environmental impacts. Therefore, it is required to pay more attention to forest road design. In this research, we tried to introduce an appropriate method for locating forest roads using GIS and AHP simultaneously. The most important layers in locating forest road include slope, soils type, geology, hydrographic networks, aspects, trees volume m3 per hectare ,tree type and elevation maps which were determined and then by using expert thought and AHP method the study area was classified in five classes including very good, good, medium, bad and worse for forest road construction. Then two new variants were designed on the prepared AHP map: the first variant was designated using traditional method and Pegger extension was applied to design the second. Pegger Planning variant (PP_variant) had the highest efficiency in path from good and bad points of view based on AHP map. The results of this study illustrated that using AHP and GIS simultaneously can introduce an appropriate and suitable method in the forest road network planning.