Ecological potential assessment for forest plantation using ANP method(Case study: Arangeh Watershed, Alborz Province)

regarding to the destruction process of natural forests, increasing human population and increasing demand for ecosystem services, the forest development and the forestry will be unavoidable. Forestry projects have grown in recent years due to environmental and socioeconomic importanc and have been raised as a developmental activity and development internationally. Therefore, before any implementation of forestry project, it should be possible to locate the susceptible areas and evaluate the ecological capability of the area. In recent years, using of multi-criteria evaluation methods has been expanded and hierarchical analysis and network analyzes have been more widely considered. The network analysis process, while maintaining all the capabilities of AHP, can address its serious constraints, including not considering the interdependencies between decision elements and assuming that the relationship between decision elements is hierarchical and one-sided, and the appropriate framework for analyzing various issues.Therefore, ANP is a suitable method for discussing multi-criteria decision-making. This research was conducted for the purpose of evaluation of ecological ability of Arangeh drainage basin located in Alborz province. ANP and geographical information system has been used in order to evaluate the forestation ability in the area.

according to previous studies and experts opinion, the indexes that were suitable for the area’s condition, were specified and after establishing of network, the questionnaires were distributed among experts and they compared the clusters and effective factors in forestry in a pair and scored by help of comparison and evaluation of the effective options in evaluating the power of forestry, it is done through questionnaire and the final weight of options calculated by super matrix limit it was determined through Super Decision software. Nine sub-criterias related to these clusters have been provided that includes slope, elevation, aspect, soil texture, erosion, temperature, rainfall, cover and types of vegetation in the environment of geographical information system with a certain clarification. Comparison and evaluation of effective options in evaluation of ecological ability for forestation by questionnaire and the final weight of options by calculating limited supermatrix is fulfilled in every questionnaire. The map of criteria has been standardized in fuzzy range of 0-255 by using IDRISI software, then the options are converted to information layers and the weight-carrying layers of indexes in geographical information system of area are assimilated by WLC technic.

the final plan of forestry ability of the area are obtained in four classes. The results of evaluation indicate that 4.6 percent has high proportion, 13.9 percent has average proportion, 19.2 percent has low and 962.1 percent have a very low proportion for forest development. Results of this study indicate that the elevation criteria has the highest and erosion criteria has the least impact to determine the appropriate areas for forestry in the studied areas.

Although considering the aquired results in this study and according to potential map of the region, forestry in Arangeh watershed is possible and the forest development has a proper to mediocre potential in 18.5 percent of the total area. The western parts of the center are in the region of Arenghe as a priority for forestry and it's advisable to check other uses for parts of the area that show inappropriate and highly inappropriate potential.