Investigation and recognition of ecological characteristics of sites of Persian Oak and Pistachio old trees in forests of Ilam province

Old Oak trees and Baneh have a special importance in Zagros forests. Recognizing ecological characteristics in relation to the position of old trees can provide good information for providing management solutions for preserving or extending the trees of the elderly. The present study was carried out with the aim of investigating and recognizing the ecological characteristics of the sites of oak and pistachio old trees in oak forests of Ilam province.

By forest survey , old trees was selected according to the DBH criterion and their site conditions including slope, aspect, altitude, soil depth, climate, site bed status, proximity to the river or source water were measured or recorded.

The results showed that the Oak old trees were generally were on a gentle slope and the Pistachio old trees were more on the relatively gentle slope. Most of the identified Oak and Pistachio old trees were located in the southern aspect. The oak old trees were distributed in 1300-1700 m from sea level, but the Pistachio old trees were in 1300-1700 and 1700-2000 m altitude classes. In terms of access to running water, none of the old oak and Pistachio trees have access to water resources and all feed on atmospheric precipitation. Crown area of oak and pistachio trees had better response to site conditions changes than their DBH and its variability depending on species kind was different. Most of the identified old trees due to locating on gentle slopes have relatively suitable soil depth than their surroundings.

Considering the optimal ecological characteristics of site situation of the identified old trees, it can be considered as the reasons for the sustainability of old trees along with their long life.