Effects of Fomitiporia punctata on the growth and wood quality of red oak

Fomitiporia punctata (P. Karst) is generally considered as a saprotrophic fungus; however, it has recently been observed on living trees, exclusively affecting hardwoods, particularly red oak, a species of major importance in North America both economically and ecologically. The fungus causes cankers and internal damage such as decay or coloration, therefore affecting wood quality. This study aimed to understand the variables associated with the occurrence of the fungus and to evaluate the internal spread of the pathogen in relation to external tree characteristics. Forty-five trees were selected in a red oak plantation established in 1993. The sample trees were felled and sawn, the resulting boards photographed, and the images analyzed to delineate the extent of affected wood on each board. In total, nearly 20% of the trees in the plantation were affected by F. punctata. The most significant factors for predicting infection occurrence were the diameter at breast height (DBH) of the tree and whether it had undergone formative pruning. Trees that had been pruned showed a lower probability of infection. Regarding wood quality, decay and discoloration were mainly concentrated in the lower 2.5 meters of the stem. Finally, an increase in the proportion of decayed wood was also observed in relation to the number of entry points and the presence of cankers.