Estimation of Strength Loss and Decay Severity of Juniperus procera by Juniper Pocket Rots Fungus, P. demidoffii in Ethiopian Forests

A juniper pocket rot fungus, Pyrofomes demidoffii is a basidiomycetous fungus responsible for damage of living Juniperus spp. However, its effect on the residual strength and on the extent of decay of juniper’s trunk was not determined in any prior studies. The purpose of this study was to study the features of J. procera infected by P. demdoffii, and to estimate the level of strength loss and decay severity in the trunk at D.B.H height using different five formulas. Infected juniper stands were examined in two Ethiopian forests through Visual Tree Assessment (VTA) followed by a slight destructive drilling of the trunk at D.B.H height. The decayed juniper tree is characterized by partially degraded lignin material at incipient stage of decay to completely degraded lignin material at final stage of decay. In the evaluated formulas, results of ANOVA showed that a significantly higher mean percentage of strength loss and decay severity were recorded in the trees of larger D.B.H categories (p＜0.001). The strength loss formulas produced the same to similar patterns of sum of ranks of strength loss or decay severity in the trunk, but the differences varied significantly among D.B.H categories in Kruskal Wallis-test (p＜0.001). In conclusion, the employed formulas showed similar to different degree of variability in quantification of strength loss or decay severity in the trunk. The findings of our study could be used as the baseline for further study on juniper’s strength loss or decays in the trunk of Juniperus spp. and unequivocally helps to design the corresponding management as result of P. demidoffii.