The Most Important Factors Affecting Persian Oak (Quercus brantii) Decline in Ilam Province

The decline of forest trees has always been one of the main problems of various ecosystems. Today’s, this phenomenon is occurring in the natural resources and forests of Zagros, and has a wider dimension every day. Various biotic and abiotic factors have been identified and introduced in different countries as the main factor or factors affecting the weakness, dryness and death of oak trees. But in Iran, the factor or main factors of the trees decline in the Zagros forest have not yet been determined accurately. The incidence and severity of this phenomenon in recent years due to the importance of forests in the province of Ilam from the viewpoint of in environmental issues and their becoming generous to oak decline, have been investigated. For this purpose, in the present study, in the multi-criteria decision-making space and the use of the AHP hierarchical process, six main criteria and a total of 28 sub-criteria were evaluated. The weight of each criteria and sub-criteria was computed by distributing 30 special questionnaires of forest specialist and obtaining opinions from experts group and using Expert Choice software version 11. The results showed that the highest weight was for drought and climate change (0.289), and the lowest weight for the quantitative and qualitative criteria of the tree and its forestry characteristics (0.097). Other criteria In order of importance were; pests and diseases (0.194), human and animal factors (0.192), air pollution (0.123) and site quality of habitat (0.105).