Assessment of Ecological Competence of Surface Expansion through GIS (Case Study: Dadabad District in Lorestan Province )

The reciprocal effect of sustainable and unsustainable ecological resources is considered in the course of assessment of ecological capacity. These resources have reciprocal effects to each other and environment as specifications of each micro ecosystem. So, it is obligatory to utilize nature as it less harms environment and at the same time it benefits human more. This is not obtained unless all effective factors and phenomena in environment are considered. In this research, to assess the ecological capacity for surface expansion of forest based on principles of reclamation of land, one of the sub- areas of Karkheh that is called Dadabad sub- area in Lorestan Province was studied through geographical information system (GIS). At first, the basic studies were done and the theme maps of the area were prepared and then numerated. Then, there were the data analysis and the collecting of layers in the GIS environment and finally the map of environmental units of area with 1581 units were obtained. In the next step, the limited areas were omitted from the map of the primary environmental units, with identifying permanent and absolute limitations in each indicator and through booleen (boolin) logic, and for surface expansion of forest a total of 1110 units with a total area of 17482 hectars were obtained without any limitation for assessing ecological capacity. After that, three separate maps were prepared and coded by differentiation of the map of soil (units and sub- units of lands): the map of measure of the organic materials, texture of the soil. Then, using bipolar distance scale, the coded qualitative values were changed to quantitative measures. These coded qualitative values in the list of descriptive data related to seven indexes included: slope, bearing, altitude, depth of the soil, texture of the soil, measure of organic materials of the soil and susceptibility to erosion that were selected as main indexes for surface expansion of forest. Next, by EC software and the process of hierarchical analysis the hierarchical structure was prepared for the considered indexes, and the objectives and criterions and relation among them were established, and in the next phase, weight of the indexes, distinction to them and studying the logical consistency of judgments were established. Final weight of each index was determined by SAW method. Then, the reciprocal effect of all the indexes related to the record of data as a final value was obtained by collecting all collective values for each record of data. Then capacity of the lands was classified in four classes of capacity for expanding forest (by considering the available values, nine is highest value and 1 is lowest value). Afterward, in the chart of descriptive data based on the available categorization, the final value. At the end, by considering the accomplished researches class of capacity 1 and 2 was selected for p