Hassan Kalantari, Asghar Fallah, Seyed Mohammad Hodjati and Aidin Parsakhoo
To determine the best form factor equation for Cupresus semervirence afforestation in Abbas Abad of Behshahr, numbers of 40 trees were selected in terms of their diameter classes, from 8 to 16 cm in 2 cm diameter classes. Then diameter at breast height (1.3 m), diameter at 0.65 m and diameter at the stump area were measured. After cutting the tree, their height and diameter at breast height were measured by diameter tape in 2 meters intervals up 5 cm diameter of trees at 0.1, 0.3, 0.5, 0.7 and 0.9 lengths were measured from each sample tree. The real from factor (fr) was compared with the mean of hohenadle (fh), normal (f0.1) and artificial (f0.5) form factors by paired - sample ttest. The results of this research showed that there was significant differences at probability level of α = 0.005 between mean of real form factor and mean of artificial from factor. Moreover there was significant differences between mean of real form factor and mean of Hohenadel from factor at probability level of α = 0.005. Therefore, mean of real from factor could be replaced by normal form factor of Cupresus sempervirence L. Var horizentalis
