Relationship of trees decaying whit wood fungi and some of habitat factors in the Shastkolateh forest of Gorgan

Wood fungi are plant pathogens، these fungi are causing decay in forest trees by decomposition of cellulose، hemicellulose and lignin. The aim of this study was to investigate the relationship of trees decay with diversity of wood fungi، type and diameter of host tree and some of physiographic factors as well as estimation of the number of infected trees by wood fungi in district one of the Education and Research Shastkolate forest of Gorgan. Inventory of the trees infected by xylophillous fungi was carried out using two strip transects، and all the infected trees were investigated in transects. To investigate a relationship between tree decay levels (ordinal response variable) and some predicator variables namely physiographic factors، host، hosts diameter and the diversity of xylophillous fungi، ordinal logistic regression was used. In this study، five species of trees namely، Fagus orientalis، Carpinus betulus، Quercus castaneifolia، Acer velutinum and Parrotia persica as the host and 9 species of xylophillous fungi were identified in the study area. Abundance of host species and xylophillous fungi increased at the end of decay classes. In this respect، there is a significant difference between the levels of decay classes. Number of trees with decayed wood in the study area of 1405 was estimated. Fomes fomentarius with 36. 76 percent have the most percentage of infection and Ganoderma austral with 1. 47 percent have the lowest percentage of infection for the trees. Physiographic factors، the type of host tree and diameter of host trees in trees decay by xylophillous fungi were ineffective، and diversity of xylophillous fungi was the most effective factor in trees decay. With increasing of the diversity of xylophillous fungi، tree decay is accelerated.