Grazing losses in natural forests of Patom section, Kheyroud district and its role on stability of forest ecosystems

Although forests are a renewable resource but increases period to ideal structure disturbance such as grazing, forest land use change, wind and fire change the forest succession. Present study examined the effects of grazing on seedling quality and their health as well as on their appearance form (multi branch and fork form). This study was done in Kheyrud forest (Patom district) with 900 hectare area. To performance this study was used 1.10000 maps for corral identification and theirs custom units after field visit. Then was established four paths from each corral that animals can move as transect to the boundary customary. Then was moved from each transect and was established 86 plots in natural regeneration groups. Dimensions of established plots was 2.5 × 2 (5 m2 ) and was done qualitative measurements in each sample plot. Then was measured species, seedling height, collar diameter of seedlings and seedling health. The results showed that was increased the abundance of seedlings in the custom unit by away from each corral and closing to custom unit boundary (from 10% to 40%). Was increased the frequency of perfectly healthy seedlings (from 9.9% to 46.3%) and semi-health seedlings (from 11.2% to 48.6%) and was decreased the frequency of browsed seedlings (from 42% to 13%) and lack of foliage (from 43.4% to 10.4%) by away from corral. The frequency of healthy seedlings on seedlings fork ratio is 30% to 70% in plots that close to corral. This trend is reversed by away from the center of custom unit and closing to customary boundary that frequency of healthy seedlings, deformed seedlings ratio is (60% to 40%). This study clearly showed that grazing has adverse impact on the quantity and quality of regenerated seedlings. So continued this situation challenges the sustainability of the forest ecosystem and forest management.