Effect of management activities and aspect on tree, soil and biodiversity variables of tree species in Dinarkuh forests of Ilam

Due to the weakness of the ecosystem in the Zagros forests, which is due to human and livestock pressure over the past decades and the occurrence of recent droughts, most of the forest areas have declined. In this situation, it is necessary to study the effects of various management activities in order to design strategic plans. To do this, the current study was conducted in Dinarkuh forest area of Ilam province to investigate the impact of different management activities on tree, soil and biodiversity variables of tree species, taken during the last decade. Experimental treatments included exclosure, exclosure + pruning, exclosure + pruning + afforestation, exclosure + pruning + afforestation + catchment system and control which considering aspect in the form of factorial statistical plan, 19 treatments with four replications were considered for each treatment. In total, 76 sample plots with area of 1500m2 were established in the field. The interested variables were measured and calculated in each sample plot and then compared between different treatments using two- way ANOVA with two factors: management activities and aspect. The results showed that among the biometric variables of trees; DBH, height, crown diameter, sprout diameter and tree density, among physical and chemical properties of soil; percentage of organic matter, silt, sand, bulk density, lime, carbon, phosphorus, potassium, soil depth, erosion and among biodiversity indices; Shannon-Wiener, Pielou and Heip indices were significantly different under management activities' areas compared to the control area. Even though, all management treatments had effective and positive effects on tree biometric variables and soil physico-chemical characteristics, as well as on biodiversity indices and in most cases made improved the current situation, considering the required costs for management treatments and their destruction in the field, exclosure can be introduced as the best management treatment in the region.