Effect of Some Environmental Factors on Diversity of Woody Plants in Juniperus excelsa Habitat of Hezarmasjed Mountains

Diversity variations of woody plant species related to environmental factors (altitude,aspect and gradient) were determined in a 3000-ha Juniperus excelsa habitat located at Hezarmasjed mountains in Khorasan Razawi province. In 130 sample plots of 1000 m 2, 16 woody species belonged to 9 families. Gradient had no significant effect on Menhinick richness (P=0.442) and Pielo evenness (P=0.220) but it affected on Simpson diversity (P= 0.001) whereas with increased gradient Simpson diversity decreased.Altitude had no significant effect on Menhinick richness (P=0.055) but with increased altitude Simpson diversity decreased (P=0.001) and evenness Pielo increased (P=0.020). Different aspects did not affect diversity indices. The current investigation revealed that advance in vegetation cover of this habitat is dependent to better management;otherwise, the increase of degradation together with elimination of the valuable plants of this ecosystem is expectable.