The effect of environmental factors on distribution of three oak species (Q. brantii Lindl., Q. libani Oliv. and Q. infectoria Oliv.) in northern Zagros forests

This study was carried out to explore the relationship between environmental factors and presence of three important oak species (Q. brantii, Q. libani, Q. infectoria) in northern Zagros forests.Following the site selection, vertical distributions were determined based on the minimum and maximum ranges species presence. A number of 54 circular sample plots, each 500 m2 were established based on various landforms and aspect. Following this, habitat characteristics including altitude, land form, slop direction, slope% and forest type were recorded. Finally a soil profile was prepared for routine physio-chemical soil analysis. The data was analyzed by means of exploratory method, analysis of variance, canonical correspondence analysis and descriptive statistics. Results revealed limitations of Q. libani concerning altitude range and aspect. The species occurs on acidic soils with low level of EC and CaCo3 and favors from heavy and semi-heavy soils. Furthermore, Q. brantii occurs on heavy halomorphic to alkaline soils with high level of CaCo3 and covers the maximum range of altitude in all aspects. It seems that soil acidity is not a limitation factor for Q. infectoria which favors from light soils and steeper northern slops.