As the climate continues to warm and pests spread rapidly, "new" tree species may be needed for "new" conditions. Native tree species are reaching their limits especially at lower elevations, yet a direct one-to-one replacement is often not possible. It all comes down to the specific site. The Federal Research Centre for Forests (BFW) has assessed the opportunities and risks of non-native tree species — that is, species not naturally occurring in Austria.

"Caution is warranted when it comes to either enthusiastic approval or blanket rejection of cultivating non-native tree species, as the results of the BFW project 'WaldWandel' show," says Katharina Lapin, head of the BFW's Institute for Forest Biodiversity and Nature Conservation. The impacts of non-native tree species cannot be generalised across the board. The site-specific risk assessments developed by BFW produced different ratings across various pilot regions — for example, the ponderosa pine is classified as "currently safe" in the pilot region of Perg in Upper Austria, whilst further trial areas are recommended in the Klagenfurt Basin and the Southern Burgenland Hill and Terrace Country to better assess the situation. Decisions made jointly in relation to a specific question at a particular location tend to be more readily accepted than those made from a purely theoretical standpoint. This underscores the importance of expertise from biodiversity researchers in the decision-making process.

It's all about the mix

A blanket assessment of "safe" or "unsafe" can only be applied to a non-native tree species to a limited extent. Potential risks and opportunities can be influenced by many regional conditions. In the pilot region of Feldkirch in Vorarlberg, for instance, there are areas where the black locust is considered currently safe, but also areas where its cultivation is strongly advised against. An individual, site-specific assessment is therefore always recommended.

You can find the full press release here!