Influence of physiographic factors on vegetative and morphological characters of Beech plus trees -A case study in Hyrcanian forest

This study was done to improve our understanding on the influence some physiographic factors including aspect and altitude on quantitative characters of beech (Fagus orientalis Lipsky) plus trees. This research was conducted in Experimental Forest Station of Gorgan University that is located in a temperate forest of Golestan province in the north of Iran. In this research, two parcels at high altitudes (800 -900m) and two parcels at lower altitudes (550 -650m) with east and west aspects were selected as well. After selecting of plus trees in every parcels, the characteristics including tree total height, stem height without branch, crown length and radius, trees diameter, annual mean growth of diameter and bark thickness were measured. Greater amounts of annual diameter growth were detected in east direction which had a significant difference (P<0.05) with west direction. Results are indicating that the tree total height, stem height without branch, crown length to total height ratio and annual growth of diameter had significant differences (P<0.01) between two altitude classes and the most total height and stem height without branch were observed in high altitude class. Crown length to total height ratio and also annual growth of diameter were decreased with increasing of altitude. Analysis of variance showed that interaction effects had no significant differences for all of studied characteristics. In total, our study supports that west slopes and upper altitudes have more appropriate conditions for growth of beech plus trees.