Clearcutting has a profound impact on forest biodiversity and forest species. Some species never return to repeatedly clearcut areas, and boreal forest species are particularly slow to recover after clearcutting.
The new findings are based on two extensive studies and more than 300 scientific datasets examining the effects of clearcutting on forest species.
“Recovery of trees after clearcutting has been regarded as an indication of sustainable forest management. However, these new findings show that even though trees start to grow on clearcuts, forest biodiversity suffers – sometimes even permanently,” says Professor of Forest Ecology Jari Kouki of the University of Eastern Finland, who is an author on both studies.
“While some species came back within 30 years – soon enough to fall within typical 60- to 80-year logging cycles – others won’t fit into that timeline,” warns biologist Dr Ellen Macdonald, a professor emerita at the University of Alberta in Canada, and lead author on the most recent study.
“If forestry operations continue on in the future with repeated cycles of the clearcutting practices they use now, some of these species are essentially never going to recover; they will start to disappear from the landscape,” Dr Macdonald continues.
“The findings are particularly compelling because we were now able to examine post-clearcutting effects across several different species groups and over the course of decades,” Kouki says.
Many earlier studies have focused on single ecological groups in specific regions, and they’ve covered relatively short time spans.
“Clearcutting not only harms endangered species, but logging may also cause permanent changes across the entire biological community, which is a concern for forest ecosystem functioning,” Kouki notes.
Some species, however, survive logging or they return to clearcut areas within the first few years or decades.
Species that thrive in clearcut forests are usually not endangered, because there is no shortage of clearcut areas or because they can also find suitable habitats outside forests.
“In Finland, more than 100,000 hectares of forest are clearcut every year. In terms of scale, that pretty much corresponds to the combined land area of all national parks in southern Finland. Species that thrive in clearcut areas therefore have no cause for concern,” Kouki says.
The new findings highlight the fact that a very large proportion of forest species, even common ones, cannot thrive in forests that are repeatedly clearcut.
“Certain forest characteristics emerge only over a long period of time. Diverse old forests will not emerge in areas that are intensively and repeatedly clearcut. Safeguarding species that are dependent on the characteristics of old natural forests requires protected areas and mitigation of the impacts of clearcutting,” Kouki points out.
At present, the most valuable forests for safeguarding forest biodiversity are natural-like old forests that have never been clearcut or that have otherwise avoided intensive forest management. Many of Finland’s remaining natural-like old forests also fall into this category. On the basis of the new findings, their protection is of paramount importance.
“It is also necessary to improve clearcutting practices. Clearcutting inevitably has a major impact on forest biodiversity because forests are logged extensively and because the effects of logging are severe,” Kouki notes.
"Forests should be allowed to grow for longer between successive clearcuts so that species have time to recover. Some trees should also be left permanently in clearcut areas as retention trees, and their number should be greater than under current practices, so that they can safeguard species also in the long term,” Kouki concludes.
For further information, please contact:
Professor of Forest Ecology Jari Kouki, University of Eastern Finland, School of Forest Sciences, tel. +358 50 538 5373, [email protected]
Research articles:
Macdonald, S.E. ym. 2026: Biodiversity recovery is slow following clearcut harvest of boreal forests. Nature Sustainability. https://www.nature.com/articles/s41893-026-01868-x
Nirhamo, A., Aakala, T., Kouki, J., 2025. Forest biodiversity in boreal Europe: Species richness and turnover among old-growth forests, managed forests and clearcut sites. Biological Conservation 306, 111147. https://doi.org/10.1016/j.biocon.2025.111147
