From spruce to beech forests - fundamental ecosystem transformation driven by climate change
Projections of the future distribution of European tree species suggest that the northern boundaries of temperate and hemiboreal forests in Scandinavia will move northwards to achieve equilibrium with the new climate. We ask: how will climate change and other stress factors interact to transform spruce ecosystems to beech ecosystems in the future?
Recent projections of the future distribution of European tree species and vegetation zones suggest that the northern boundaries of temperate and hemiboreal forestss in southern Scandinavia would move nortwards by 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, todays’s ecosystems that are dominated by Norway spruce are projected to be transformed to beech and mixed beech forest ecosystems, imlpying that key-stone species composition, biodiversity, ecosystem function and services are to be altered. These expected major ecosystem transformations call for knowledge about their rates, drivers and societal consequences. Regarding this, it is worth to metion that the Norway spruce is the economically most important in Norway. In this project we combine retrospective, descriptive and experimental approaches to explore the relationships between climate change, land-use stress, and the occurrence and ecological 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 nort-western distribution limit here. In particular we will target stress induced by land-use that 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 temporal perspective as both historical stress mainly caused by anthropogenic use of fire and recent stress induced by forestry is examined.
The overarching question in our project is: how will climate change and other stress factors interact to transform Norway spruce forest ecosystems to beech forest ecosystems in the future? To address this question, we combine retrospective, descriptive and experimental methods in four approaches to: I) Explore the relationship between past land-use stress, climate change and the occurrence of Norway spruce and beech forests in SE Norway; II) characterize microbial diversity in soil and plants (e.g. mycorrhiza- and endophytic fungi) in spruce, beech and mixed forests; III) determine rate of ecosystem transformation and spruce forest tipping point when beech invades; and IV) assess if and how climate change and land-use stress by forestry (logging activities) interact to transfer spruce forests to beech forests. These four approaches tie together well because they integrate climate change, biodiversity, ecosystem function, and past and present stress by land-use.
Through southeast Norway runs a boundary between northerly coniferous spruce forests and southerly deciduous beech forests. Projections on future climate change based on the HadCM3 climate model predict that this boundary will move north over the coming years, with beech trees replacing spruce as conditions change favourably for them.
The spruce today represents an economically important tree species to Norwegian forestry, with beech wood regarded as less versatile and useful, so advancing beech forests could have a negative impact on this industry in the future. A change in the dominant species of tree will also likely lead to further transformation of the ecosystem, with profound changes occurring at all levels down to the microscopic decomposers in the soil.
Marie-Charlotte Nilsson, Swedish Agricultural University
Richard Bradshaw, University of Liverpool
Håvard Kauserud, Uinversity of Oslo
Anne Bjune, UNIResearch Bergen
27/02/2017 - 13:24