Investigation of the relationship between drought of Iranian oak trees with stand structure, physiographic factors and soil (Case study: Mian Tang forests of Ilam)

Subject Areas :

Mehdi Ahmadi ¹ , Ali Rostami ²

1 - M.Sc. Student of Silviculture and Forest Ecology, Department of Natural Resources, Ilam Branch, Islamic Azad University, Ilam, Iran.
2 - Assistant Professor, Department of Natural Resources, Ilam Branch, Islamic Azad University, Ilam, Iran.

Received: 2021-12-12 Accepted : 2022-01-19 Published : 2021-02-19

Keywords: Physiographic Factors, Persian Oak, Oak decay, Edaphic factors, Mian Tang area,

Abstract :

 The phenomenon of vegetation drought, especially in arid and semi-arid regions, has always been one of the main problems of various ecosystems. Numerous factors cause this phenomenon in plants, the most important of which are climatic factors (decrease in rainfall and increase in temperature) and the presence of pests and semi-parasitic plants such as loranthus. The aim of this study was to investigate the relationship between forest tree droughts and stand structure, physiographic factors and soil in the Mian Tang forests of Ilam province. For this purpose, after combining slope, direction and altitude maps, a sample plot was randomly implemented in each of the homogeneous units, and the quantitative and qualitative characteristics of the trees were measured in a circular sample plot with an area of 12 r. and recorded in census forms. According to the results, it was found that the decline of oak trees in the study area is affected by a combination of trees, stands and habitat. The results showed that 37.5% of the oak trees in the region were damaged by drought, of which 54% had a vegetative form and 58% of the damage was observed at the branches. The trees in the floors of 65, 60 and 50 cm in diameter and 8, 6 and 10 meters in height, as well as with canopy diameters of 8, 9 and 7 meters were more damaged by the oak decay phenomenon. The results also showed significant differences in some soil properties such as bulk density, electrical conductivity, organic matter, nitrogen, phosphorus and potassium in dry and healthy trees.