Abstract

This study was conducted to investigate the relation among the bending of trees caused by snow weight in coniferous and broadleaved species using the Height of tree: Diameter of breast height (H: D) ratio and crown projection area (CPA). For this purpose, the diameter, height and the bending angle of trees as well as theCPA in plots were respectively measured using caliper, clinometer and laser rangefinder. Results in broadleaved species showed that the CPA had more effects than that of H: D ratio, but in coniferous species the H: D ratio had more effects on bending of trees. We found significant linear relationship with equation of Y=1.827x^0.66 among CPA and the rate of trees bending (R² = 0.6). Also, there was significant difference between trees bending in different classes of H: D ratio (P > 0.05, for broadleaved species), and we found significant linear relationship with equation of Y = 191.4x² – 122.9x + 30.44 among H: D ratio and the rate oftrees bending (R² = 0.7). There was significant difference between trees bending in different classes of CPA (P>0.05, coniferous species). The branches angle in most of the broadleaved species is irregular, so this status causes collection of uneven snow on crown of trees. It is most important especially at the edge of forest roads, because the trees bending and breaking is dangerous financially and health-wise. So, a deciduous species with deep root system must be selected for planting at the edge of forest roads.

Key words: Bending of trunks, broadleaved species, CPA, coniferous species, H: D ratio, snow.