The effect of forest structure on some physical and chemical soil properties in the forests stands of Kurdistan province

Structural properties of forest stand affect forest soil and soil characteristics. The purpose of this study is to investigate the changing of soil physical and chemical properties under different forest structure in Kurdistan province. At first, four one-hectare (with dimensions of 100 × 100 m) plots were selected in Baneh (two stands), Marivan and Sarvabad (one stand) and structural characteristics of stands were determined. Seven soil samples were taken from a depth of 0-10 cm in each site (a total of 28 soil samples) and the physical and chemical were measured. Results of one-way analysis of variance test show a significant difference in most of the physical and chemical properties of soil (except nitrogen and electrical conductivity) in the four stands. The results showed that forest stand with young coppice structure (with higher canopy percentage ) increased organic carbon (3.15%), absorbable potassium (5.37 mg/kg), absorbable phosphorus (10.5 mg/kg), electrical conductivity (483 d s m-1) and soil moisture content (9.95%) in compere of another site. The results of principal component analysis showed that the first and second components account for 90.27% of site changes and the first component includes electrical conductivity and potassium variables and the second component includes absorbable phosphorus, organic carbon and weight moisture. Considering the positive effect of forest stand with young coppice structure (with higher canopy percentage and higher tree density) on the forest soil, it is recommended to regenerate and develop the forest in coppice stands with a density of less than 150 tree in hectare.