عنوان مقاله [English]
Background and objectives: In the Zagros forests, borer beetles will outbreaks after recent year's drought stress and physiological weakness in host tress and they causes accelerate mortality trend. In other hands charcoal disease outbreaks and then continue on oak decline has become one of the main problems of Iran oak forests. The aims of this research is studying the relationship between borer beetle damage and charcoal oak disease in the Kakasharaf forests of Khorram Aabad.
Materials and methods: The study area is the Kakasharaf forest of Khoram Abad is located on the Zogros forests in the west of Iran. This forest region is one of the infection focuses of charcoal disease. Inventory grid with dimensions 200 m × 150 m in the GIS software was drawn and placed randomly on the study area. To study the infected trees in the intersection grid sides, circular plots being 15-are (1500 sq m) in area were used. All the trees that were the hosts to Biscogniauxia mediterranea and borer beetles were considered. Used the linear regression for study of the relationship between charcoal disease and borer beetles damage and anowa test was used to investigate extent and damage intensity of charcoal disease and borer beetles in the sprouts of infected trees.
Results: The results showed that trees in the study area with the severity of 92.96 % and 47.04 % respectively to charcoal disease and borer beetles had been infected. Linear regression showed a strong relationship between the borer beetles damage with percentage of dieback (R2= 94.5), and the borer beetles damage with charcoal disease percent (R2= 85.9). The number of sprout showed significant differences at a confidence level of 99% for infected trees to charcoal disease and borer beetles. Cutting and pruning branches and twigs showed a significant impact on infected trees to borer beetles and charcoal disease, cuted trees more by borer beetles (41.43 %) and pruned trees more by charcoal disease were infected.
Conclusion: In the study area human interferences such understory planting, fire, overgrazing livestocks, deforestation by man, cutting and pruning branches to make fuel and livestock feed and as well as ocurence environmental stresses are causses trees weakness and infected to pests and diseases. According to the results about two-thirds of trees to had cut and prune branches were infected to borer beetles and charcoal disease. Borer beetles can be important factor to charcoal disease transport between trees. So that this research showed there is strong relationship between damage borer beetles and charcoal disease.