Volume Increment Determination of Forest Stand Types in the District One of Dr Bahramnia Forest Management Plan, Gorgan

It is necessary to calculate the volume increment for estimation of annual allowable cut in forestry plants. In order to compute increment of main species in district one of Dr. Bahramniaʹs forest, firstly, forest divided to four forest zonation based on basal area ratio of tree species including Fageto-Carpinetum, Carpineto-Parroetum, Parrotio- Carpinetum and Mixed types. Then, 140 circular plots (0.1 hectare) were sampled with randomly-systematic method (300×400 meter network) in the study area. Using increment borer device, core sampling of increment (2-3 trees in each sample plot) was extracted from north-side of tree at breast height from 419 trees. Volume increment of main species and forest stand types were calculated based on the Meyer’s method. The correlation analysis results showd that variables of diameter at breast height (d) and volume increment (Iv) are significantly correlated to each other for studied tree species.