Stem traits, compartments and tree species affect fungal communities on decaying wood

Dead wood quantity and quality is important for forest biodiversity, by determining wood-inhabiting fungal assemblages. We therefore evaluated how fungal communities were regulated by stem traits and compartments (i.e. bark, outer- and inner wood) of 14 common temperate tree species. Fresh logs were incubated in a common garden experiment in a forest site in the Netherlands. After 1 and 4 years of decay, the fungal composition of different compartments was assessed using Internal Transcribed Spacer amplicon sequencing. We found that fungal alpha diversity differed significantly across tree species and stem compartments, with bark showing significantly higher fungal diversity than wood. Gymnosperms and Angiosperms hold different fungal communities, and distinct fungi were found between inner wood and other compartments. Stem traits showed significant afterlife effects on fungal communities; traits associated with accessibility (e.g. conduit diameter), stem chemistry (e.g. C, N, lignin) and physical defence (e.g. density) were important factors shaping fungal community structure in decaying stems. Overall, stem traits vary substantially across stem compartments and tree species, thus regulating fungal communities and the long-term carbon dynamics of dead trees.

Automated summary

Dead wood quantity and quality play a crucial role in forest biodiversity by influencing wood-inhabiting fungal communities. The diversity of fungal communities varies across tree species and stem compartments, with bark exhibiting higher fungal diversity than wood. Different fungal communities are associated with gymnosperms and angiosperms, and distinctive fungi are found in the inner wood compared to other compartments. Stem traits, including accessibility, stem chemistry, and physical defense, have significant effects on fungal community structure in decaying stems.