The Impact of Polypore Fungi on Growth and Physiology of Yellow Birch and Molecular Detection of Fungal Pathogens in Live Trees

Pathogenic fungi, such as polypore fungi that infect live sapwood, decrease quality and value of wood; however their effects on canopy physiology and growth have been little examined. This study examines how Fomes fomentarius, a species of polypore fungus affects canopy physiology in Betula alleghaniensis. A mobile canopy lift enabled the collection of leaf physiology, morphology and chemistry data from canopies of infected, damaged, and control trees. A molecular protocol developed to detect and identify polypore fungi in live trees confirmed that F. fomentarius was the major species present in infected trees. Infected trees exhibited reductions in physiological performance and growth, along with higher leaf carbon and chlorosis. While some characteristics of fungal infection were consistent with a mechanism involving partial xylem occlusion, patterns did not resemble those of a simple drought response. Likely, other factors such as fungal toxins or host defense mechanisms also contribute to these patterns.MAS