Adapting forests to climate change: Evaluating opportunities and risks of non-native tree species on ecosysem services

Stockholm

2024

2467

Bandaufführung

40005064

Forestry is facing unprecedented challenges due to increasing climate change threats and disturbances. Particularly, economically important tree species are being lost and it is often unclear if native or non-native tree species (NNT) can be used as alternatives. The choice of tree species for climate-smart forests should not only take productivity, carbon sequestration and economic efficiency of forests into account, but also forest biodiversity and the provision of other ecosystem services. Using species distribution models of native and NNT as well as data from the Austrian forest inventory, we modelled the provision of various ecosystems services of Austrian forests under current and future climate conditions and by applying various species selection scenarios. The ecosystem services encompass the productivity of forests, their protective function against avalanche and rockfall events, as well as their resistance to wildfire. Five different species change scenarios were evaluated: (1) no tree species change, (2a) replacement of lost species with native tree species which are climatically most suitable, (2b) replacement of coniferous with native coniferous trees and deciduous with native deciduous trees, if appropriate; (3a) replacement of lost species with nonnative trees if they show a higher suitability to future climate; (3b) replacement of coniferous with non-native coniferous trees and deciduous with non-native deciduous trees, if appropriate. The results indicate that relying solely on native species would result in a decline in both productivity and biodiversity in terms of tree species composition. This negative impact can be mitigated by increasing the proportion of NNT. However, it is important to note that the selection of native or NNT has a lesser effect on the protective function of forests. Depending on whether productivity, the protective function (ecosystem service) or tree species diversity (biodiversity) are considered, different species selection scenarios can be recommended. Accordingly, a good balance of tree
species is of particular importance in order to be able to meet the different requirements of climatesmart forests. Especially in the protection forest, different aspects are important than in production forest. Our results provide a knowledge basis for Austrian forest owners/managers to make decisions on a sustainable choice of tree species.