Assessment of diameter growth of beech (Fagus orientalis Lipsky) in Guilan province

Beech (Fagus orientalis) is one of the most valuable species in Hyracanica forest which contain 26% of standing volume. A National project was planned and carried out to assessment of growth and performance of Fagous orientalis in Asalem region. In this study, eight plots were selected in different aspect and elevation from550 up to 2000 m. a. s. l. Each plot covered one hectar and in terms of dbh classification, five trees were selected in each plot. Tree height, dbh, diameter at median height, crown height and crown diameter was assessed. Other characteristics such as crown layer, crown health, crown size warp and branchiness of stem was considered. The obtained results of this study indicated that trees under 80 cm diameter had 170 m3 volume per hectar. The calculated form factor for beech was 0/4075. The value of mean annual increment was 3/47 m3. Correlation analysis showed that there was significautly correlation between height and age, diameter and age as well as dbh class and mean height crown, depth and dbh crown size.