An Investigation on Effects of some Ecological Factors on Distribution of Different species of Amygdalus In Ilam province

In this research , areas that covered with Amygdalus spp. Were distinguished and marked on map with 1:50000 scale. Based on three ecological factors such as: elevation, geographical aspects and geological formation. These areas were divided to 126 ecological units. Overall, after deleting the similar units, 57 units were identified and used for tree and site sampling. The stratification sampling method was used. Finally 126 original plots and 252 sub plots (200*200m) were randomly allocated to each ecological unit. The following site and tree parameters and characteristics were studied and measured: site altitude, aspect, gradient, geology, soil type and depth, climate and tree height, canopy diameter. Height and area percentage, collar diameter of the tallest stem, density and regeneration. Results show that there are four species and two subspecies of Amygdalus in Ilam province, with total area of 118802 hectars. The species A. lycioides and A. scoparia are growing in four climates : moderate dry, moderate semi- dry, cold semi- dry and cold semi humid.A. orientalis is growing in two climates : cold semi humid. and upper elevations. The range of elevation for the species A. scpoparia, A. lycioides and A. orientalis is 400, 1700 , 600, 1900 and 1300-2500 m. above sea level respectively.