بررسي شكل ساقه درختان راش بر مبناي شاخص هاي اندازه اي و جنگل شناسي ( مطالعه موردي: جنگل هفتخال ساري)

Trunk morphology of beech trees (Fagus orientalis Lipsky) on biometrical and silvicultural criteria (Case study: Haftkhal forest, Sari, north of Iran)

Trunk (stem) specifications of the beech trees (Fagus orientalis Lipsky) vary in different sites of Hyrcanian forests. To study the morphology of the trunk of these trees in natural unmanaged Haftkhal forest, 30 sample beech trees in three diameter classes of <50, 51-75 and >75cm were surveyed. For the sample trees, diameter at different levels of stem measured in two ways: a) constant distances from the ground level with 2.5 m intervals, b) relative height levels with coefficients of 0.1 tree height. Criteria used for this research are: diameter at breast height (dbh), tree total height (H), mean of the two crossed crown diameters (C), tree thinness factor (H/dbh), form class, equation of dbh and H, equation of dbh and C, diameter reduction factor (drf), tree form factor (Ft) and trunk form factor (Fs) with volume base and diameter base, ratio of trunk length (h) to H, ratio of volume in different levels of stem (Vs) to tree total volume (Vt), geometric form of the different length of trunk (logs), form similarity of the different trees trunk, effect of the distances mean of adjacent trees on the beech stem specifications and finally, correlation and mathematical equations between the above-mentioned factors. Some of the results are: mean of (H/dbh) is 0.52, (Ft) factor is 0.48, the ratio of (h) to (H) is 0.64. Furthermore, it is found that about 74 percent of the Vt is located in lower half of the (H), the rate of stem similarity vary with the growing stages, and finally, (C) has a high correlation with diameter at breast, mean height and the treeʹs distance from adjacent trees and (dbh) and (H).