To be successful in tree establishment, an assessment of land suitability would be necessary. The aim of this study was determining the potential habitats of three native tree species (Quercus persica, Pistacia atlantica, Amygdalous scoparia) in Siahkoh region of Ilam County, using Boolean method and Geographic Information Systems (GIS). For this regard, the slope, aspect and hypsometric maps of the area were produced using topographic maps. To provide soil properties maps, 40 soil samples in depth of 30 cm were randomly taken from the defined region (about 954 ha). Soil sample properties such as pH, texture, electrical conductivity, and organic material were measured. Soil maps and soil data layers were produced in GIS environment. With respect to ecological needs of the selected tree species and combining of all provided maps, about 890 ha of the total area could be reforested or afforested. The results show that from the total suitable area, 368.72 ha (41.41 %) for Quercus persica, 353.44 ha (36.69 %) for Pistacia atlantica and 176.2 ha (19.78 %) for Amygdalus scoparia were found to be suitable for these species. The results of comparing the extracted suitability map with the existing 30 ha afforestation in the region show that, from 10 hectares afforested by each species, Quercus persica, Pistacia atlantica and Amygdalus scoparia 7.65, 3.11 and 4.25 ha are located in the high suitable areas, respectively.
