Abstract

To provide a better understanding of natural stand dynamics of Scandinavian broadleaved forests we studied pattern of tree mortality in a semi-natural beech Fagus sylvatica forest at Biskopstorp, SW Sweden. The primary goals were (1) to assess beech mortality rates of different tree condition classes (TCC) and transition probabilities between them, and (2) to suggest likely mortality drivers in the studied beech population. Mortality rates and transition probabilities were calculated between pairs of six TCC (live trees, live high stumps, dead trees, dead high stumps, stumps, and logs) by using data from two complete censuses of a 3.9 ha stand (ntrees = 1189) over a ten year interval (1996-2006). The total annual canopy tree removal rate reached 2.0% following two main pathways: (1) stem breakage leading to instantaneous death (1.1% yr-1), and (2) stem breakage leading to partial crown removal, resulting in formation of a living high stump, HSTL (10.5% yr-1). HSTL was characterized by an increased mortality rate (11.5% yr-1). HSTL made up ca10% of the living trees in both censuses indicating importance of this feature in the dynamics of the beech forest. Only two uproots were recorded (0.04% yr-1), despite of two hurricanes (in 1999 and 2005) that occurred during the study period. Mortality was significantly higher in trees above 60 cm DBH than in smaller trees (4.0% vs 0.7% yr-1, respectively) and no differences were found among smaller DBH classes. Trees with fungal fruit bodies (FFB) had a significantly higher mortality than trees lacking FFB (7.6 vs 1.1% yr-1, respectively). Our results highlight the role of the living high stump stage in the dynamics of the beech forest and suggest that the combination of wind and fungal infection of Fomes fomentarius are the main drivers of mortality in the studied stand

Keywords

hardwoods; forest history; dendrochronology; mortality; regeneration; community dynamics; natural succession

Published in

Ecological Bulletins
2010, volume: 53, number: 53, pages: 117-129
Book title: Broadleaved Forests in Southern Sweden: Management for Multiple Goals
ISBN: 978-1-4051-8886-9
Publisher: The Nordic Society Oikos

Authors' information