Snag dynamic in a mixed Beech forest

Dead tree, which consisting of both standing dead tree and material that has fallen to the ground, is a dynamic resource in forest ecosystem. In order to investigate on falling and dynamic model of snags (standing dead trees) in a mixed beech forest, this research was carried out in compartments No. 112 and 214 in Kheyroud forest, north of Iran. 215 dead trees were measured and then 64 dead trees were randomly selected for analyzing. According to the results, hornbeam snags in a natural forest showed higher breaking height in comparison to beech snags. Investigation on snag dynamic showed that snag falling is higher on steep slopes, however, there is no significant difference between slope gradient and snag falling. Increasing in decay class, caused increasing in sang falling. Also effect of dead wood size, decay stage (quality of dead wood), slop and species were analyzed. Results showed that slop and species have no significant effect on the sang falling, while the effect of deadwood size and decay stage on sang falling is significant.