The assessment of degradation to sustainability in an urban forest ecosystem by GIS

Different factors affect the sustainability of urban forests. In this study, in order to distinguish the parameters affecting an ecosystem, the man-made Sorkhehesar Park of Iran was divided into homogeneous units (HUs) in accordance with natural (slope, aspect, elevation, soil depth, pure and mixed planting systems) and human (irrigation and recreation levels) factors using GIS, and their effects on ecosystem sustainability were investigated. All tree and shrub species (Fraxinus excelsior, Cercis siliquastrum, Platanus orientalis, Robinia pseudoacacia, Cupressus arizonica, Pinus eldarica, and Cupressus sempervirens) individuals of the park were studied qualitatively and quantitatively. Homogeneous units were identified on the basis of tree height, basal area, crown diameter and symmetry, tree vitality, canopy cover, and density of herbal vegetation. Results showed that the sustainability of the ecosystem was affected by different factors and the limiting factors were pure and mixed plantation system, slope, and soil depth. Local recreation resulted in unsustainability of the site in areas with slopes more than 15% and shallow soil. It was concluded that the status of C. siliquastrum and C. sempervirens individuals was more stable in similar conditions compared to other species.