Autecology and phenology of Pistacia atlantica in relation to edaphic and physiographic factors in Kabirkoh forests of Darreh Shahr county, Ilam province

This study conducted with aims to investigate autecology and phenology of Pistacia atlantica in relation to site conditions in Kabirkoh forests of Ilam province. Based on the land forms area, 8 clusters and 40 sample plots were taken in each landform unit. In each sample plot, three soil samples were taken from 20 cm depth and one mixed sample soil created from them and transferred to Lab. For phonological study, randomly two sample 1 ha plots were selected in each landform unit and phonological stages of pistachio trees were investigated every week. The results showed that the establishment, quantity characteristics and phonological stages are influenced by topographic condition, especially aspect and soil characteristics. According to RDA analysis, two distinct groups in the study area were identified. Quercus brantii and Pistacia atlantica have gathered together as a group on south facing slope and represented higher values of OC, P, K and N. In contrast to the first group, Acer monspessulanum and Amygdalus scoparia were indicator species in the second group. This group had high correlation with elevation and has been located on north facing slope. The starting and ending dates of phenological events also were different between these two groups.