THE IMPACT OF MOOSE BROWSING ON TREE SPECIES COMPOSITION IN FINLAND

• Main Authors: Heikkilä, Risto, Hokkanen, Pertti, Kooiman, Mira, Ayguney, Nilay, Bassoulet, Cyril
• Format: Article in Journal/Newspaper
• Language: English
• Published: Lakehead University 2003
• Subjects: Alces alces; North Finland
• Online Access: http://alcesjournal.org/index.php/alces/article/view/481

The attitude usually adopted in Finnish forestry regarding the moose (Alces alces) has traditionally been that it influences Scots pine in young mixed stands and therefore intensiv treatments have been recommended to favor monocultures. The need to maintain diversity across the landscape is, however, changing attitudes. We tested the hypothesis that selective browsing can influence the composition of tree species in young stands, both in managed and natural forests. Moose browsing effect on sapling heights was compared in exclosures and adjacent open areas in the south- and mid-boreal forest zones of Central and North Finland at the end of the 1990s. Moose appeared to impact young trees by reducing height growth, thereby reducing the possibility of selected broadleaved species to reach maturity. The number of aspen trees can obviously be expected to greatly decrease as a result of regenerating suckers being browsed by moose. Rowan considerably declined under browsing pressure. On the other hand, the results also suggest that moose browsing may be beneficial by releasing conifers from competition among tree species in managed forests. In this sense, the relationship between browsed birches and the condition of conifers is crucial. Browsing obviously reduces tree species diversity in areas of high moose density. However, some trees sheltered by neighboring ones are not browsed, and more information is needed about optimal treatment of young stands. In Finland’s relatively small nature conservation areas, repeated browsing can quickly retard the height of slowly-regenerating broadleaf species. This browsing impact may lead to ecosystem changes without significantly impacting moose populations, the management of which by hunting is restricted in the set-aside natural forests and conservation areas.