Comparison of effective factors in exploiting the forest damage in forest management plan of Neka Zalem Rud

This study aims at determining the main damage caused by logging in single selection method causing open holes in forests. Little is known about this subject, in spite of extensive studies worldwide. Amount of damages based on the FAO criteria in plots and hectare were assessed according to type, size, intensity and height of damages. Quantitative data of two compartments were compared using t-test. One-way ANOVA and Kruskal-Wallis tests were used to compare multiple groups for quantitative and rating data, respectively. Data were collected by survey of land and one hundred percent measurement in damaged parts. In cutting stage, 79.5% damages were occurred in height >1 m. In skidding stage, 90.4% of damages to wood were observed from a height of 1 meter downward the trunk to the tree root and buttress. The average of the most injuries in the two compartments in cutting and skidding stages were observed in size of 10-50 cm² (44%) and > 200 cm², respectively. The intensity of damage in cutting stage is the same (72 percent), but higher in skidding stage, because the slope of cut area in compartment 51 is higher than compartment 121 (95 percent versus 63 percent). The total intensity of damages in compartment 51 was higher than compartment 121 (33 damages versus 19). The rate of injuries to regeneration in compartment 51 in all three stages of vegetation development was higher than compartment 121. The types of damages to stem in compartment 51 were 2 up to nine times, depending on the development stages. The total damages in steep slope were more than gentle slopes (4 times). Ignoring the prescribed cutting direction has a large effect on damage caused.