Abstract
Using the HadCM3 climate scenario, recent projections of the future distribution of European tree species and vegetation zones suggest that the northern boundaries of temperate forests and hemiboreal forests in southern Scandinavia would move northwards b y about 300-500 km to achieve equilibrium with the new climate. In a South-East Norwegian perspective, such a future change of vegetation and forest types imply that huge areas and their ecosystems will go through fundamental transformations. For example, today's ecosystems that are dominated by Norway spruce are projected to be transformed to beech and mixed beech forest ecosystems, which will be a truly fundamental transformation as key-stone species composition, biodiversity, ecosystem function and ser vices are to be altered. These expected major ecosystem transformations call for knowledge about their rates, drivers and societal consequences. Regarding this, the importance of Norway spruce in the Norwegian forestry sector deserves to be mentioned - th e species is actually the economically most important tree in Norway. In this project we will combine retrospective, descriptive and experimental approaches to explore the relationships between climate change, land-use stress, and the occurrence and ecolo gically functioning of spruce- and beech forests in South-East Norway. Our reason for focusing on this part of Norway is that it provides a "natural laboratory" with landscapes in which spruce- and beech forests meet as beech reaches its north-western dis tribution limit here. In particular we will target how stress induced by land-use interacts with climate change to alter robustness and tipping-points in spruce forest ecosystems, and thereby speeding up their potential transformation into beech forests. Here, the impact of the land-use stress will have a temporal perspective as both historical stress mainly caused by anthropogenic use of fire and recent stress induced by forestry operations will be examined.
Norway