Moose browsing on Scots pine in relation to stand size and distance to forest edge.
Abstract
Moose (Alces alces) browsing on Scots pine (Pinus sylvestris) was studied in young stands of different sizes (1, 10 and >100 ha) and at different distances from old forest edges (5, 20, 100 and 400 m) in single areas in both northern and southern Sweden. In both study areas, damage was neither significantly related to stand size nor to distance to edge. In the southern area damage was significantly higher in glades within (<0.1 ha) mature forest than in the young forest stands. However, most of the variation in browsing intensity on pine was due to differences between stands, irrespective of size and distance to forest edge. Using stepwise multiple regressions 30-40% of the variation in damage could be explained. The most important variable was density of young Scots pine in the stands, damage decreasing with increasing density. A second significant variable was density of moose, measured as the density of faecal pellet groups. Browsing was also observed on the deciduous trees birch (Betula pendula and B. pubescens), aspen (Populus tremula) and rowan (Sorbus aucuparia), which moose prefer over pine. These species were mostly heavily browsed, and will probably not develop a natural tree shape. The study suggests that stand size will be of little importance as a management tool for reducing browsing pressure on pine by moose. However, management can influence the densities of young Scots pine. Browsing was reduced when the density of young trees exceeded about 1500 and 2500 ha-1 in the north and south, respectively.