Effects of management on coarse woody debris volume and composition in boreal forests in northern Sweden

Abstract

Forest management practices have led to a reduction in the volume and a change in the composition of coarse woody debris (CWD) in many forest types. This study compared CWD volume and composition in reserves and two types of managed forest in the central boreal zone of Sweden. Ten areas were surveyed, each containing clear-cut, mature managed and old-growth stands, to determine the volume of standing and lying CWD in terms of species composition, decay class and size class. Volumes of CWD on clear-cuts and in mature managed forests were high compared with previous studies. Old-growth forests (72.6 m³ ha⁻¹) contained a greater volume of CWD than mature managed forests (23.3 m³ ha⁻¹) and clear-cuts (13.6 m³ ha⁻¹). Differences were greatest for the larger size classes and intermediate decay stages. Despite stand ages being up to 144 years, CWD volume and composition in managed forests was more similar to clear-cuts than to old-growth forests.

Keywords:

• Boreal forests
• clear-cuts
• coarse woody debris
• decay state
• forest management
• logs
• Norway spruce
• old-growth forests
• size class
• snags

Acknowledgments

Support for this project came from the project “Conservation of Biodiversity in Managed Forests”, financed by the Faculty of Forestry at the Swedish University of Agricultural Sciences. We are grateful to the Kempe foundation for funding, and the forestry companies Holmen Skog AB, Sveaskog AB, Scaninge for stand information and use of sites within their forestry areas, to Fredrik Stenbacka for assistance with the fieldwork, and to our colleagues Barbara Ekbom and Thomas Ranius and two anonymous reviewers for comments on a draft of this manuscript.