Due to differentiation ecosystem units and related soil physico - chemical and physiographic characteristics, 75 ha of virgin forest in Aghouzchal were studied. Vegetation data and information (trees, shrubs, and herbs) were collected from 60 sample plots with systematically random method (20 m × 20 m) which were then analyzed by using of TWINSPAN program. The data were classified to four ecological groups. Some of physical, chemical and characteristics of soil, such as soil acidity (pH), bulk density, soil moisture, organic carbon, total nitrogen, available phosphorous, soil texture litter carbon, and litter nitrogen were measured. Elevation, aspect and slope were recorded in every plot, too. Principal component analysis (PCA) was used to determine correlation as well as distribution in each ecological group of environmental factors. It was noticed that 2nd, 3rd ecological groups had the highest correlation with the 1st axes whereas 1st and 4th ecological groups demonstrated the highest correlation with the 2nd axes. The results indicated that the ecological group’s distribution pattern was mainly related to elevation factor and soil characteristics such as pH, phosphorous, organic nitrogen, and soil nitrogen.
