Polypore diversity was studied in woodland key habitats varying 0.05–3.6 ha in size.
Patch size and volume of downed logs were the main factors affecting species richness.
Richness of species, incl. red-listed, increased up to 20–30 m3 ha−1 of downed log volume.
Edge effect affected humidity up to 50 m into forest interior.
Several factors reduce the probability of species surviving on patches <1 ha.