Evaluating Plant diversity and some features of Oriental beech in different tree-layers (Case study: Beech forests, Asalem, Guilan)

The present study aimed to examine the effects of stratification on tree layers diversity and some features of beech trees in Hyrcanican forest, Guilan, Asalem. Also, interactions between tree diversity and some characteristics of beech leaves was investigated. The Nine research plots are sampled as a gradient from pure beech stands to mixed stands with up to 9 deciduous tree species with three replications for each. Each research site had a size of 2500 m2 (50 m × 50 m). In each tree layers, diversity indices, crown diameter, DBH and frequency of beech tree were measured within plots. The results showed that the highest value of richness and diversity indices belonged to the second tree layer. The highest amount of basal area and crown diameter were observed in the first tree layer (overstorey). Regression analysis showed that tree layer diversity and richness measures were significantly positively correlated with fresh and dry weight of beech leaves. Correlation coefficients indicated that beech frequency was significantly positively correlated with weight of fresh leaves and negatively with dry weight of leaves. There was significantly negatively correlation between basal area of beech trees with fresh and dry weight of leaves within stands. In general, it can be stated that diversity-functioning relationships might occur in the tree-layer of the deciduous beech forest under investigation.