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Research article2013Peer reviewedOpen access

Retaining trees for conservation at clearcutting has increased structural diversity in young Swedish production forests

Kruys, N; Fridman, Jonas; Götmark, Frank; Simonsson, Per; Gustafsson, Lena

Abstract

Retaining trees for conservation at final harvest is becoming increasingly common within forestry globally, especially connected to clearcutting. The main action is to leave single living and dead trees, tree patches and buffer strips, to benefit biodiversity and to enhance ecosystem functioning. We present the first national analysis of effects on structural components from applying the retention approach. In Sweden retention forestry has been practiced large-scale for about 25 years, prescribed by the law and a requirement in certification standards. By analyzing data from the Swedish National Forest Inventory we found that the volume of dead trees (>= 100 mm in diameter; single trees and trees in patches <0.02 ha; data for larger retention patches not available) in stands 0-10 years old increased about 70% during the period 1997-2007, with a current average level of 8 m(3) ha(-1), and with a larger increase rate in this age class than in other forest ages. Retained living trees (>= 150 mm in diameter; single trees and trees in patches <0.02 ha; data for larger retention patches not available) decreased in quantity from 1955 until the early 1980s, with lowest levels of about 5 ha(-1) (excluding Pinus sylvestris, commonly used as a seed tree) and then increased, approximately reaching the 1950s level by 2007, with about 15 trees ha(-1) on average. Large-scale application of the clearcutting practice is the probable cause of the decrease, whilst retention actions are the likely explanation for the increase during the last decades. Our study clearly shows that young forests have become structurally richer since the introduction of the retention approach in forestry. However, comparatively low amounts of dead wood in forests 0-10 years old compared to what is available in old forests imply loss at harvest and studies of possible mechanisms to explain this are needed. Our results can indicate possible changes in other parts of the world, where the retention approach has been introduced more recently. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Keywords

Biodiversity; Dead wood; Logging; Monitoring; National Forest Inventory; Variable retention

Published in

Forest Ecology and Management
2013, Volume: 304, pages: 312-321 Publisher: ELSEVIER SCIENCE BV