رابطه بین عوامل خاکی و تراکم زادآوری گونه راش در روشنه¬های تاج پوشش با اندازه مختلف

In temperate forests canopy gaps play an important role in driving stand dynamics. The purpose of this research was to compare soil characteristics in forest gaps with several size and its relation to Beech regeneration density in Lalis forest, Chalous. In order to investigate factors, three gap sizes as small gap (200 m2), medium gap (400 m2), and large gap (600 m2) with three replicate were selected in locatation. Mineral soil samples were randomly collected from four different places in each gap, all over the gap area. Nine circular subplots of 3.14 m2 were established inside each gap on two principal diagonals and the regeneration density of Beech species was estimated. Some of soil characteristics, such as total carbon, total nitrogen, available phosphorous, soil acidity (pH), C/N ratio, saturation moisture and soil texture (clay, silt and sand) were measured. Results showed that the carbon and C/N ratio significantly decreased with increasing of gap size. The other soil characteristics significantly increased with increasing of gap size. Similar to results, statistical difference between regeneration densities with soil characteristics was found. With thicken of soil characteristics consisting of nitrogen, phosphorous, pH, and moisture, regeneration density increased. Carbon and C/N ratio affected negatively on regeneration density, But there were no significant differences in soil texture ingredient between gaps.