The effect of altitude on quantitative and qualitative characteristics and estimation of Pistacia ‎atlantica fruits in the forest stands in Sardasht, West Azerbaijan province

Pistachia atlantica has inimitable stability and tolerance to unsuitable natural conditions. The study ‎aimed to investigate the quantitative and qualitative characteristics of P.atlantica stands in ‎altitude classes and to estimate the amount of fruit production in the studied stands. In this study, in ‎three altitude classes of Sardasht forests (less than 1400 m, 1000 -1400 m, and more than 1400 m), the ‎traditional utilization area of six villages was selected and in the forest stands of the mentioned villages, ‎‎27 transects of unequal length were randomly established. In the transects, characteristics such as ‎species type, tree height, d.b.h, small and large crown diameter, origin, health status, and distance ‎between trees were measured. Also, the amount of fruit of 89 individuals in different diameter classes ‎was measured. The results showed that in the studied stands, Pistachia atlantica accounted for 11.1% of ‎the mixture, and the average d.b.h and the height of trees were the highest in the elevation class less ‎than 1000 m and 1400-1000 m, respectively. The highest seed-originated tress percentage of Pistachia ‎atlantica individuals was observed in the altitude class of 1400-1000 m and the highest percentage of ‎healthy trees was observed in the altitude class of more than 1400 m. The two characteristics of height ‎and average diameter of the crown show a positive correlation with the amount of fruit produced in ‎each individual. This study showed that with increasing altitude, the abundance of Pistachia ‎atlantica reduced and the quantitative and qualitative characteristics of trees show significant changes.‎