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Abstract
Evaluation of Forest Road Network Variants by Backmund Method, Using GIS and Field Investigation
Seyed Mehdi Alizadeh
University of Tehran,
Iran
Email: s_malizadeh@yahoo.com
Aliasghar Darvishsefat
Associate Professor
University of Tehran
Email: adarvish@ut.ac.ir
The most important cost factor in forest management involving a great deal of investment cost is road construction. 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 variant 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 improve planning process.The objective of this study is designing and evaluating of forest road network variants for Chelir district of Kheiroodkenar forest which is 845 ha and choosing the best variant on the basis of Backmund technical criterion and finally evaluating of the selected variant in the forest. There was a 4733 meter constructed road in this district. The road coordinate was determined using GPS data and was delineated on the district digital topographic map. In order to do more appropriate planning, the mentioned road was used to plan different road network.A digital elevation model (DEM) was derived from digital topographic maps at the scale of 1:25000 and was used to provide terrain data such as slope and aspect.Firstly 18 road network variants regarding technical principles were designed using PEGGER (an extension for Arcview software). All variants were evaluated from a technical stand of view in GIS using Backmund method. The variant which was selected as the best variant was checked with hand clinometers and strip meter in the field. The results suggest the utility of GIS to improve planning methods.
Keywords: forest road, road network, planning, GIS, Backmund method, GPS, DEM, PEGGER
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