Commercial clear-felling of trees is more harmful to fungi than forest fires, according to a recent doctoral thesis published at the Natural Resources Institute Finland (Luke).
A senior scientist at Luke, Kauko Salo,has investigated the impact of forest changes — logging, ditching, fertilisation and forest fires — on fungi, based on empirical field data, which included more than 550 species over a monitoring period of up to 12 years.
The study found that forest fires have a mainly positive effect on mushrooms, but the intensity of the fire is of great importance to the composition of fungi communities. The number of species of the mushrooms in mild fire sites is three times higher than in high-severity fire sites, the research found.
"Edible mushrooms including rufous milkcap, velvet bolete, foxy bolete and Russula paludosa [isohapero in Finnish], benefit from mild forest fires," Salo says.
Harmful effects of logging can be mitigated
Mushrooms are an integral part of the forest ecosystem. Some fungi form a symbiosis with the roots of trees, improving their growth. The study stated that the harmful effects of logging can be mitigated if live coniferous and deciduous trees are left as logs for harvesting.
Live retention trees — those left permanently standing after clear-cutting to promote regeneration — help fungi that form a symbiotic relationship with trees.
Some fungal species also decompose and recycle organic matter from dead trees or other plant debris, which is then beneficial to other plants and animals.
A large number of edible and commercial fungi are also economically important, according to Salo.