The comparison of forest structure in Oak stands with different density and mixture (Case study: Noyjian forests of Khorramabad)

This study was carried out in Noyjian forests of Khorramabad, the destructed and less destructed stands were investigated in terms of three structural aspects: species diversity, spatial pattern and dimension variation have been compared. For this purpose, at first based on the available information and see the forest closely, two classes of crown dense 35% and more than 35% were bounded. Then in each of this part, 10 (one-acre) sample plots were taken with the similar physiographic conditions. According to the results, the diversity in these stands is low, but in general, the diversity in the less destructed stands is more than the sparse stands. Among the species diversity indices, the Margalef index shows the most difference. In relation to the pattern of distribution, the mean aspect and uniform angle indices show similar results based on random distribution of most species in both stands. According to the dominant index these species (Quercus brantii, Acer monspessulanum and pears) are dominant and other species are defeated. In general, the mean of the differentiation index shows a large difference between canopy coverings in different stands, which is more than that in sparse stands. According to the result, in general, the structure of less- destructed stands is in a more favorable position in different aspects. Since the physiographic conditions of these stands are similar, human factors can be considered as the main cause of the apparent difference between these stands. Therefore, it can be concluded that in the reduction of these factors, protection and support of destructed stands, the condition of this destructed stands will be more desirable.