بررسي و تعيين ميزان رويش قطري و حجمي گونه راش در يك جنگل طبيعي كم دست خورده در منطقه ناو اسالم

Diameter and volume increment of (Fagus orientalis Lipsky) in an intact forest of Nave-Asalem region.

Beech (F. orientalis Lipsky) is one of the valuable species of Caspian forests of Iran which shares about 30% of the forests growing stock. Measurment of the annual diameter and volume increment of this species is essential for accurate planning and logging. Furthermore, measuring the annual allowable cut for the forest management projects, is based on the annual volume increment. The trial was conducted in district one of Nave-Asalem forest Management Project at west forests of Guilan province. In the control compartment of this district, 30 circular plots, each 500 m2, were randomly allocated. In each plot, in addition to measuring different variables, three trees were used to sample growth increment cores and calculte the annual volume increment by the Meyer method. The annual volume increment of F. orientalis at the studied intact stand was calculated after measuring its annual diameter increment, which was 10.284 sylve per hectar per year. For further investigation, the annual volume increment of the species was calculted at three diameter classes, including 15-45 cm (young trees), 45-75 cm (middle - aged trees) and > 75 cm (old - aged trees), which resulted in: 0.0295, 0.0512 and 0.735 sylve per hectare per year, respectively. There was significant correlation between breast height diameter (dbh), annual diameter increment and annual volume increment.