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Research article - Peer-reviewed, 2022

Increase in dead wood, large living trees and tree diversity, yet decrease in understory vegetation cover: The effect of three decades of biodiversity-oriented forest policy in Swedish forests

Kyaschenko, Julia; Strengbom, Joachim; Felton, Adam; Aakala, Tuomas; Staland, Hanna; Ranius, Thomas


In Sweden, the majority of forest area has been altered by industrial forestry over the decades. Almost 30 years ago, a shift towards biodiversity-oriented forest management practices occurred. Here we took advantage of long-term data collected by the Swedish National Forest Inventory to track developmental changes in forest structural components over this time. We assessed changes in structural components that play an important role in biodiversity (dead wood, large living trees, tree species composition, and understory vegetation) in four forest types with descending tiers of biodiversity protection: protected areas, woodland key habitats, low-productivity forests and production forests. Overall, we found a positive trend in the volumes of dead wood and large living trees, as well as in tree species diversity, while there was a general decline in understory vegetation coverage. Most observed changes were consistent with the intended outcomes of the current forest policy, adapted in the early 1990s. The implementation of retention forestry is likely driving some of the observed changes in forest structural components in the south. In contrast, we observed no changes in any of the focal structural components in the north, which could be attributed to the ongoing clear-cutting of forests previously managed less intensively. Dead wood and large living trees increased not only in managed, but also in unmanaged forests, likely reflecting historical management. The increased tree species diversity can be explained through current forest management practices that encourages maintenance of additional tree species. Decreasing understory vegetation coverage in both dense managed and unmanaged forests suggests that factors other than forestry contribute to the ongoing changes in understory vegetation in Swedish forests. Overall, the observed increase in structural components has not yet been reflected in documented improvements for red-listed forest species, which may be due to delays in species responses to small improvements, as well as a lack of detailed monitoring. Similarly, the increased availability of forest structural components might still be insufficient to meet the specific habitat requirements of red-listed species.


Biodiversity; Swedish NFI; Production forests; Low-productivity forests; Woodland key habitats; Protected areas; Forest structural components; Forest management

Published in

Journal of Environmental Management
2022, volume: 313, article number: 114993

Authors' information

Swedish University of Agricultural Sciences, Department of Ecology
Swedish University of Agricultural Sciences, Department of Ecology
Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre
Aakala, Tuomas
University of Eastern Finland
Staland, Hanna
StoraEnso Skog AB
Swedish University of Agricultural Sciences, Department of Ecology

Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification

Environmental Management
Forest Science

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