The effect of single-tree selction system on soil properties in an oriental beech stand of Hyrcanian forest,north of Iran

A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small (60–150 m²), medium (151–241 m²), large (242–332 m²) and very large (333–550 m²) gaps, as well as under closed stands were studied eight years after the gap creation. Soil samples were taken from three depths, 0–10, 10–20 and 20–30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters: Mg⁺² concentration of 0–10 cm at medium gap size, bulk density of 10–20 cm at very large gap size as well as K⁺ and Ca⁺² concentrations at 20–30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent (Sp %) at 0–10cm as well as P and Mg⁺² at 20–30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10–20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca⁺² at depth 0–10 cm and 10–20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.