Forest road design combining common design techniques and GIS (Case Study: 2nd series of Liresar Forest)

Nowadays, it is necessary to apply modern techniques for the design of road networks, especially roads passing through ecosystems such as forests, in order to reduce operating costs, prevent further degradation of the environment, increase road efficiency and achieve sustainable development goals. In this paper, a new way of designing the road is presented. New design method has the ability to analyze a large amount of information in a variety of digital layers using GIS while being able to store, recover, and analyze information through multi-criteria decision-making process (AHP) and routing algorithms at high speed and precision. The output of the proposed design method (combining information with AHP via Dijkstra algorithm in GIS software) is compared with the existing forest road in the 2nd series of Liresar in Mazandaran province of Iran, designed using common methods. According to experts, hydrological criteria (0.408) and environmental criteria (0.375) have the highest importance and weight in comparison with other criteria in forest road design. The results show the map of area's capability for road construction is prepared for road design with better functionality and less adverse effects on the environment using the divider method compared to conventional topographic maps. Finally, the design of the new road in comparison with the existing reduce the slope (5%), increase access (15%) and reduce the cost of construction (30%).