امكان سنجي طراحي و ارزيابي گزينه هاي مختلف شبكه جاده با بهره گيري از GIS و بررسي هاي ميداني ( بررسي موردي: بخش چلير - جنگل خيرود )

Possibility of Designing and Evaluation of Forest Road Network Variants Using GIS and Field Investigations (Case Study: Kheiroud Forest - Chelir District)

Forest roads as the first basis of land organization in forest management units have an undeniable role. With appropriate planning of road network, performance can be highly increased while the extra costs decreased. Therefore, it is necessary to evaluate many road variants in an area to choose the optimal one with respect to technical criteria. Planning of road network using traditional methods is very time consuming, so due to decreasing the planning time, the number of variants decreases and this will decline the technical quality of planning. GIS-based planning methods have the capability of analyzing a great deal of data as different digital layers with high precision and speed, so they can help the planning process to be improved. The objective of this study was designing and evaluation of forest road network variants considering primary designing principles (minimum length-maximum coverage area) using GIS and assessment of their performance on the field. Final evaluation was carried out based on performance of variant on the field. Therefore, present road coordinate was determined using GPS and was used to plan road network variants. 18 road network variants regarding technical principles and forestry necessities were designed using PEGGER (Arc View extension). All variants were evaluated from a technical stand of view in GIS using Backmund and Segebaden methods. Regarding Backmund proposed variant and management necessities, the variant which was selected as optimal variant was checked in the field. Finally, the changes were applied on it. The results suggest the utility of GIS to improve planning methods.