Journal of

Natural regeneration is the most important principle to maintain and sustain of vegetation in each region, therefore, doing the research about the relationship between natural regeneration and environmental factors can be useful for conducting a better management in these regions.Therefore, this study aimed to investigate the effects of physiographic factors and soil parameters on natural regeneration of trees and shrubs species in the forest of Baye Mountain in Eyvan city, Ilam province. Using systematic random sampling, 27 plots were implemented in the area with a total area of 900 square meters. Then environmental factors (physiographic and soil) and the number of natural regeneration were studied and measured. Correlation analysis showed that Cerasus microcarpa regeneration had positive correlation with OM and Ca and negative with EC. Regeneration of Acer monspessulanum L. had negative correlation with clay, and Amygdalus lycioides regeneration had positive correlation with silt, while there was no significant correlation between other species and other soil factors. The results showed that elevation had significant effects on natural regeneration of Cratagus pontica and Amygdalus lycioides, while the slope of gradient hadn't any significant effect on regeneration. Only, aspect had significant effects on Cerasus microcarpa regeneration, and regeneration of this species in the eastern and northwestern direction was more than other aspects.

This study was conducted to investigate the effect of aspect on woody species structure and diversity in the Persian oak (Quercus brantii Lindl.) site, Dashtak area, Kohkiloye and Boyer Ahamd province in western Iran. Measurements were carried out in 3 elevation classes range from 2200 m to 2400 m a.s.l. Then, three sampling plots with area of 2500- m² were selected in each elevation class. In total, five tree species, including Quercus brantii, Crataegusdavisii, Pistacia atlantica. Subsp. mutica, Lonicera nummulariifolia and Amygdalus communisand three shrub species such as Cerasus microcarpa, Amygdalus orientalis and Daphne mucronata were identified in the study area. In regeneration and tree layers the sum of basal area and average of regeneration's density was higher in southwestern aspect and belonged to Quercus brantii. The results of diversity indices in the tree layer indicated that the average of H^’ (Shannon-Wiener index), E_var (Smith-Wilson index) and species richness were higher in southwestern aspect than in the northeastern aspects. In addition, the values of all diversity, evenness and richness indices were significantly higher in southwestern aspect the in shrub and regeneration layers. In general, the results indicated that the diversity indices increased under favorable conditions of ecological, environmental and structural factors. Furthermore, livestock access and exploitation of local people should be restricted off, providing favorable conditions in order to increase the diversity of species.