Burning harvested sites enhances polypore diversity on stumps and slash

Abstract

Abstract Prescribed burning after clear-cut is a traditional silvicultural method used for promoting regeneration of new tree cohort, but it also affects biodiversity of the harvested sites. We studied, on sites dominated by Pinus sylvestris with Picea abies admixture, how burning of clear-cuts affects wood-decaying fungi on stumps and slash left on sites. In total, 18 sites, nine of which were burned, were studied in a large-scale field experiment in eastern Finland. Polypore fungi were surveyed 10 years after the burnings. In total, we sampled 13,083 stumps and 12,023 pieces of slash and counted 6,598 polypore records of 54 species. Burned stumps hosted more polypores than unburned stumps, but burning had no effect on polypores on slash. Both stumps and slash hosted also some red-listed polypore species – more so, if the resource was burned. The results show that stumps and slash can be valuable substrates for wood-decaying fungi, including rare and red-listed species. We recommend avoiding full-scale, intensive stump and slash harvest e.g. for bioenergy, and to apply prescribed burnings on harvested sites, to enhance polypore diversity in managed forests.