Effects of dead trees on natural regeneration of beech trees in different physiographic ‎conditions (case study: Siahroud forests, Langaroud)‎

The aim of this study was to study the effects of altitude and slope factors on beech natural regeneration around dead trees in Siahroud forests of Guilan province. In order to conduct this research, 45 dead trees were selected using selective sampling method. Then, around the standing dead trees, a circular plot with a radius of 5meters and around the fallen dead trees, a rectangular plot with 4meters width (2meters from two sides of each log) were measured. Inside each plot, regeneration frequency, slope (in three classes of <30, 30-30 and > 50%) and altitude (in three classes of <700, 700-1500 and >1500 m) were measured. In order to compare regeneration in 50m distance from dead tree, the measured variables were collected in samples with the center of healthy trees with the same DBH. The results showed that the regeneration frequency of all tree species around dead trees was higher than around of healthy trees. The ANOVA test showed that there is a significant difference between the regeneration frequency in different classes of altitude and slope. Also, with increasing altitude and slope, the regeneration frequency of around healthy and dead trees was decreased. The results showed that physiographic factors have an important effect on the tree regeneration around of dead trees.