The Effect of Physiographic Factors on Quantitative Characteristics of Forest Types (Case Study; Vaz Research Forest)

Different ecologic factors influence on forming, development and sustaining of the plant communities, among which physiographic variables are the most important ones. The aim of this study was to identify forest types and effect of physiographical factors such as sea level height, slope and aspect of the site on quantitative characteristics of forest types in 2^nd district of Vaz Forest with area of 847.5 ha in Chamestan city (Mazandaran Province). The field data were collected in 256 plots. Inventory grid was designed by a random-systematic method with dimension of 150×200 meter and sample circle plots with radius of 17.84 meter. In each sample, some of quantitative tree factors e.g., diameter breast height and control trees height were recorded. In order to recognize the type, total surface average equal to trees basal area in sample plot and Two Way Indicator Species Analysis (TWINSPAN) were used. Forest stands were grouped into seven forest types. In order to compare forest types and the role of physiographical factors on their quantitative characteristics, ANOVA and Duncan tests and Spearman correlation coefficient were used. The results showed that forest types are not only different in floristic characteristics but also in physiographic characteristics of sites. Other results also showed that the 6^th forest type has minimum mean of basal area, volume and height of the control trees. It was also found that there were significant differences between mean of basal area and mean of volume, mean of regeneration and vegetation cover and mean of control trees height with geographical directions and sea level height, slope percent of the site and sea level height, respectively. It is notified the category of the sea level height (1200-1600 m) was recognized as an optimal condition for Beech stands (Fagus orientalis Lipsky.).