资源环境科技发展态势分析平台

Wood decay fungus Pyrofomes demidoffii is a cosmopolitan spp. and considered as an important source of damage to Tuniperus spp. The aim of the study was to assess the wounding factors of Juniperus procera and their relation to a disease occurrence of P. demidoffii in some afromontane forests of Ethiopia. Disease survey and sample collection was conducted during 2010 in Adaba-Dodola and in Menagesha forests. In Adaba-Dodola forest, sampling was conducted in highly disturbed forest blocks named as non-"WAJIB" and in a relatively undisturbed forest ("WAJIB") named after the local Man Oromic language. WAJIB blocks are constitute of Forest Dwellers Association established to protect forest, whereas a non-WAJIB blocks are people living in villages found adjacent to forests with little role in protection of forest. In both study areas, a study quadrat of 20 x 20 m(2) within the plot was established at 100 m intervals along a regular grid. In each sampling unit, comprehensive survey was conducted to determine the occurrence of infection by P. demidoffii. About 657 trees (310 in Adaba-Dodola forest and 347 in Menagesha forest) were assessed for the typical signs and symptoms of P. demidoffii. Natural and anthropogenic wounding factors were assessed, and their relationships with disease occurrence of P. demidoffli were determined. Pyrofomes demidoffii was noticed as fruiting bodies and/or white rot on the juniper stands. The disease occurrence of P. demidoffii was significantly higher in juniper stands with a mixed wounding factors followed by wounding by bark-peeling (P < .0001). The disease occurrence was significantly associated with crown vitality status (P < .0001) and significantly higher in juniper stands with complete-die back. The disease occurrence in the intact juniper stands was much lower both from fruiting bodies (9.1%) and white rot (3.6%) as compared to other decay stages. Trees with larger diameter at breast height (d.b.h) and larger wound size displayed significantly higher disease occurrence of P. demithiffii (P < .0001). Wounding at any point has resulted in the infection of the tree by fungal inoculum of P. demidoffii. From the current study, it can be concluded that wounding of the juniper tree by mixed wounding factors followed by bark peeling; wounds of larger size; heavily decayed and hollowed trees; completely declined stands, and stands with larger d.b.h. categories enhanced the susceptibility of juniper tree to P. demidoffii to a greater extent.