Community structure of wood-decay fungi following wildfire in ponderosa pine forests

Background/Question/Methods The process of post-wildfire wood decomposition is important to forest ecosystem functioning because it influences carbon dynamics, nutrient availability, soil physical properties, and the potential for reburning. Decomposition estimates commonly emphasize abiotic factors, such as temperature and moisture, and analyses of the relevant fungal communities are often superficial because they are limited to aboveground sporocarps. However, recent advances in genetic molecular techniques have made it possible to identify the fungal species responsible for wood decay to a much greater extent. In this study, we sampled wood from logs and snags representing a range of decay classes and time since fire to assess fungal community composition and diversity. We expected to find differences in community structure at different aged sites as a result of succession, as well as effects of decay state, wood size, and type (log or snag). Using terminal restriction fragment length polymorphism (RFLP) techniques on both mycelial isolates and DNA extracted directly from the wood, we determined the presence and relative abundance of fungal taxa and analyzed their community composition. Results/Conclusions The RFLP pattern analysis demonstrated that fungal species richness and community composition changes with time since fire. Fungal community composition was similar for the two more recent fire sites, but differed for the older fire site. Our results suggest that the diversity of wood decay fungi may affect the rate and type of carbon being decomposed, and, therefore, provide an important link to post-wildfire nutrient cycling in ponderosa pine forests.