Effect of soil physical and chemical properties on tree cover diversity and structure in Marivan Qamyshlh forests

This study was conducted to assess the effect of soil physical and chemical properties on diversity and structure of tree cover in oak forests with an area of 275 hectares in Qamyshlh city of Marivan Kordestan, Iran. For this purpose, a total of 90 samples, each 10 yards, randomly laid out on a regular gird network were selected and in the center of each plot, soil samples were taken at the depth of 0 - 30 cm. Results revealed that the average diameter of trees had a significant positive correlation with phosphorus, potassium, organic matter and carbon to nitrogen ratio in the soil. The results also showed that there is no significant relationship between the most measured soil characteristics and richness, evenness and diversity indicators. However, soil pH with Pirlo and Simpson indexes and phosphorus with Margalef index had a significant negative relationship. Correlation between the percentage of tree species and soil characteristics showed that among the studied species, Q. branti were more sensitive to changes in soil properties compared with other species. However, the analyses of ordination methods showed that there is no direct relationship between species distribution and soil properties. In addition to the soil effects, due to the proximity of the forest land to rural residential areas, it can be said that the most influential factor in shaping the composition, diversity, and structure of Qamyshlh tree species are human factors.