Effect of Exclosure on Density and Diversity of Natural Regeneration in Mixed Stands of Arasbaran Habitat

Natural regeneration is responsible for the conservation of species and the protection of biodiversity in forest stands and an important step in forest dynamics towards sustainable management. In order to evaluate the effect of long-term exclosure on the density and diversity of natural regeneration, two forest habitats were selected including excluding stand and control stand, regenerations were measured and counted in six sample plots with an area of one hectare. Regenerations were divided based on height into four categories: seedlings, coppice large saplings, standard large saplings, and small saplings. the indices of richness, diversity, and evenness were calculated and statistical analysis was performed for each habitat. The results of the density showed that the exclosure area had a higher number of regeneration densities per hectare. The types of regeneration classes were more frequent in the exclosure area, except for coppice large seedlings, which were more abundant in the control area. Diversity and evenness indices were less in the control area than the exclosure habitat with a significant difference, but the richness index was not significantly different (p≤0.05). A successful stand recovery process is necessary to enhance regeneration and community sustainability in the future. Enhancing natural regeneration is a cost-effective way to improve the quality of forest stands. Based on the results, it is proposed to determine the optimal duration of exclosure in order to prevent the reduction of biodiversity and also to investigate the effect of exclosure on soil seed banks in the studied area.