Quantitative and qualitative characteristics of trees and some site factors in natural habitats of Velvet maples (Acer velutinum)in Asalem

Acer velutinum is one of the most important forest species which forms a pure stand in the Asalem region (Guilan province). In this research, four untouched habitats or with less anthropogenic impacts were selected for A. velutinum in Asalem forest watershed catchment No.7. Then, the most important quantitative and qualitative trees characteristics and also some soils’ physico-chemical factors and geomorphological factors including the height from the sea level, altitude, percent slope and aspect were examined. The number of individual trees per hectare, diameter, total height of trees, grade quality, and symmetry of the crown were determined for all individuals in order to examine the growing stock condition of the species in each natural site (the mean was considered for these factors). The obtained results showed that there was a significant difference between the diameter, height and volume of the standing trees (per hectare), while there was no a significant difference between the symmetry of the crown and tree quality grades in the study area. The results of soil surveys demonstrated that the available phosphorus of soil and soil texture were two important variability factors in the study area. Based on the obtained results, the growing stock of A. velutinum has an optimal condition towards northern direction with low slope areas and height around 800 m.