Snow damages in related to physiographic factors in Asalem-Nav forests, Guilan province

Snow damage is a significant and serious problem in management of mountain forests. In this research snow damage on trees in related to physiographic factors were studied in Asalem-Nav mountain forests in the Guilan province. The ground slope of study area was divided in tow slope classes: lower and upper than 50 percent. The frequency of damaged trees in lower and upper than 50 percent of ground slopes was 10. 5 and 18. 2 percent. The results showed that the frequencies of damaged trees have significantly differences in two ground slope classes (P < 0. 001). The frequencies of tree damage types of crown damage، stem breakage and uprooting in the slopes of upper than 50 percent was higher than slopes of lower than 50 percent. The trees on the northern aspect slopes were more damaged than southern aspect slopes، so frequency of damaged trees on northern aspect slopes was 17. 6 percent but on the southern aspect slopes was 10. 3 percent. The trees of Beach، Hornbeam، Great maple and Cappadocian maple in northern aspect slopes، while the trees of Alder and Oak in the southern aspect slopes have more susceptible to snow damage. In order to strengthening of trees against to the snow damage needs to adequate silvicultural operation in mountain forests.