عنوان مقاله [English]
In order to determine the ecological groups in Sisangan Forest Park and study its relationship with soil variables, reserve area of the park (approximately 543.5 hectare) were evaluated. Total 46 systematic-selected sample plots, about 400 m2 (20×20 m) for estimation of tree, shrub and herb vegetations in the field of mixed Bux tree, pure stands and non-Bux were almost equal numbers were selected. TWINSPAN vegetation analysis program was used to classify ecological groups which resulted formational of three above mentioned groups. After site classification, indicator species values were accounted by IV method. Soil acidity, moisture content, electrical conductivity, organic carbon, total nitrogen, available phosphorus and potassium, soil texture and ratio of organic carbon to total nitrogen in each plot at the depth of 0-15 and 15-30 cm were determined. Significant consideration of soil variables within groups, one-way analysis of variance and Duncan’s group mean comparison range were applied; and for gradient analysis of soil factors PCA was used. Sample plots in PCA and DCA showed that each samples of plant groups were stayed closed together and they form the idiosyncratic groups. Statistical analysis showed that soil acidity, available potassium, electrical conductivity, organic carbon, ratio of organic carbon to total nitrogen, moisture content and soil texture are the basic characteristics’ variability in ecological region.