Planning forest routes for silvicultural activities using GIS based techniques: A case study of Selesjö in Östergötland, Sweden.

Abstract: Forests are natural resources that provide essential services for different groups of users from human beings to native habitats. They are actually home of diverse range of biological groups; contribute to alleviate climate change through sinking carbon-dioxide from the atmosphere and supplying oxygen back to it and finally they are regarded as wood resources by human beings. In recent decades, exploitation of forest woods, specifically by application of operational machineries, has exerted severe pressure on basic elements of forests, such as soil and water. Massive weights of harvesters and forwarders could cause soil compaction, rutting and runoff formation which threatens regrowth and biodiversity in soil and water systems. All these environmentally negative impacts could be avoided or at least minimized if forest operational activities are accompanied by proper and intelligent pre-planning. Geographic Information System (GIS) is one of the technological achievements with great potentials that can assist decision makers in exploring scientific questions, analyzing various alternatives and evaluating possible choices of actions through computer systems. This study developed a GIS-based technique for planning main access routes for logging operations in harvesting sites in a manner to minimize environmental damages to soil and water. A model was created within the model builder environment of the ArcMap, version 10, using the existing tools in Spatial Analyst and 3D Analyst extensions of the ArcMap. A cost-index surface consisting of major effective factors i.e. elevation, slope and soil type was created to be fed into the Path Distance tool in order to perform distance analysis .The model was run over two separate study areas to evaluate possible route designs within the harvesting sites. Two distinct route layouts, corresponding to predefined scenarios, were suggested by the model for each of the study areas to connect the landing point(s) to some arbitrary destinations inside the harvesting border. The novel achievement of this study could be regarded as the proper route alignment with respect to the slope direction of the ground in the ArcMap environment, to avoid lateral inclination of loaded forwarders on the steep slopes.