Wood-decomposing fungi and seed-tree cutting: A 40-year perspective

The effects of logging on wood-decomposing Basidiomycetes were studied in the boreal forests in northern Finland. The study area consisted of pine forest sites felled 3, 18 and 42 years before our study. The species composition of fungi in cut plots was compared to that of uncut old-growth forest sites. Altogether, 47 species were recorded on 570 logs. The species compositions reflected the amount and quality of coarse woody debris (CWD) available in the stands. In the old-growth stands, the species diversity was high, but the distribution of fungi was strongly affected by the patchy occurrence of CWD. Pioneer white-rot fungi predominated in the 3-year old logging sites. In the 40-year old logging sites, the number of species on the logging waste was 50-60% lower than in the old-growth forests, but the residual CWD from the pre-logging time still hosted a large portion of the species of the virgin forests. The species regarded as old-growth forest indicators showed different ecological tolerance to the effects of logging: the majority was confined only to naturally produced CWD, while some species were able to invade logging waste. The results showed that some polypores known to prefer old-growth forest habitats can survive for decades in managed forests. However, the species diversity of lignicolous fungi after logging greatly depended on the availability and diversity of decaying wood created before the management.