Effect of altitude and edaphically factors on competition between Amygdalus orientalis species: (Case Study: Tang Khoshk forest reserve in Semirom)

Forest reserves are protected areas and the analysis of relationships between vegetation and environmental factors in these areas is ecologically considered as an important issue. To investigate the role of altitude and edaphically characteristics in Tang Khoshk forest reserve in Semirom Esfahan، thirty 0. 2 ha circular plots were randomly established. Four circular subplots were also laid out within each main plot and the competition between shrubs was measured by Schütz competition index. Slope، aspect and elevation were recorded within each plot. For each subplot، soil samples from two depths (0-30 and 30-80 cm) were taken. Soil properties including total nitrogen، organic carbon، organic matter، available potassium and phosphorus، pH and electrical conductivity were measured. Factor Analysis (FA) was used to analyze the data. The results indicated that، nitrogen، carbon and organic matter of both depths are the most important factors affecting the competition followed by slope، elevation and potassium content of the first depth. Generally، it could be concluded that soil factors are of higher importance among all physiographical and edaphically characteristics influencing competition between Amygdalus orientalis species in Tang Khoshk forest reserve.