The role of hillshade regime on canopy density and evaluation of ecological capability in the Zagros forests (Case study: Kabirkooh forest of Badreh city, Ilam province)

The purpose of this research was to investigate the role of hillshade values, in comparison with terrain aspect, in the canopy changes and evaluation of ecological capability in vegetation domain of Zagros forests. In conducting the research, digital elevation model (DEM) was prepared and soil map was extracted from that. Due to the direct relationship of forest canopy with the site ecological capability, the raster map of hillshade was multiplied by forest canopy; and canopy area was calculated at different values of the hillshade map. Also, the map of the main slop aspects extracted by the DEM map and that was multiplied to the map of forest canopy. Then canopy area was calculated for different aspect; and that was presented as a histogram. Thereupon, the histogram and quadratic model equation of relationship between forest canopy percent and hillshade regime was prepared, in the entire study area. The histogram and the model, show that reducing the intensity of sunlight (Rising Shadow), strong influence on the increase in canopy. Also, the quadratic regression model (R2 = 0.58) and linear regression model (R2 = 0.56) of the correlation, with 17 repetitions, obtained in the form of a square block network. Because of the easiness and the low cost of hillshade mapping, and also, its superiority over the terrain aspect map; we recommend that hillshade maps be used as one of the key factors for of land ecological capability, in the Zagros forest and other arid and semi-arid forests.