Microfungi from Bark of Healthy and Damaged American Beech, Fraser Fir, and Eastern Hemlock Trees During an All Taxa Biodiversity Inventory in Forests of the Great Smoky Mountains National Park

Abstract

The assemblage of microfungi associated with bark samples of healthy and damaged Fagus grandifolia (American beech), Abies fraseri (Fraser fir), and Tsuga canadensis (eastern hemlock) trees was evaluated during an All Taxa Biodiversity Inventory of the Great Smoky Mountains National Park in 2003 and 2004. Bark samples were collected from sampling points 0.3, 0.6, 0.9, and 1.2 m above the ground surface on the bole of each replicate tree. Patterns of species composition and diversity (species richness) were evaluated from bark samples over three sampling dates (May, July, and September) each year. A total of 4814 isolates were obtained, with greater than 95% belonging to the Deuteromycota. Over 94 species of fungi were identified from bark of the three tree species, which were either healthy or were damaged or under pressure from exotic pests. The most common genus was Trichoderma, for which a total of 13 species were identified during the two-year study. Frequencies of microfungi between healthy and damaged trees were similar across years, but when data was compared by year, frequencies were significantly greater in 2004 than 2003. Species richness was almost always significantly greater in September than in May and July. Frequencies of microfungi isolated from bark samples collected 1.2 m above the ground were significantly greater than in samples collected at 0.9, 0.6 and 0.3 m. Increased species richness at the higher bole positions was likely related to changes in microenvironment, as proposed by previous researchers. All other comparisons of species richness were similar.