Soil-wood interactions: influence of decaying logs on composition of soil fungal communities

Fungal communities inhabiting dead wood may affect soil fungal communities directly underneath the wood by the presence of their exploratory hyphae. Wood leachates from decaying wood may also influence soil microbial communities. We studied fungal community composition in four-year old decaying logs of Larix kaempferi and Quercus rubra, in soil directly underneath and next to the logs. Fungal community composition differed clearly between wood and soil samples, between soil taken underneath and next to logs, and also differed per tree species. Soil fungal diversity decreased over time under logs of both species, reflecting the low diversity found in decaying wood. The amount of exploratory hyphae of log-inhabiting fungi was only high close to decaying logs. We conclude that there is a small but significant effect of decaying logs and tree species on soil fungal communities directly underneath logs due to the presence of exploratory hyphae and differences in wood leachates between different dead tree species.