Few tree species can withstand climate shifts, scientists say

European forests are already feeling the harsh impact of climate change. A joint study by the University of Vienna and the Technical University of Munich evaluated which trees can best withstand current environmental stressors for reforestation. Their investigation revealed that just a handful of species, including the pedunculate oak, are suitable for this purpose.

Published in “Nature Ecology and Evolution” (http://dx.doi.org/10.1038/s41559-024-02406-8), the research team highlighted the critical role of mixed forests in maintaining ecosystem stability. They pointed out that relying on a limited number of species is insufficient for forest survival, as monocultures are especially vulnerable to various threats.

Out of the continent's tree diversity, the study examined 69 species, identifying nine as potential candidates for future continental reforestation and four for Great Britain. This selection must navigate the challenge of surviving the imminent cold spells and the warmer temperatures projected for the century's end. Dr. Wessely notes the complexity of choosing trees that can thrive under both present and future climate conditions.

Yet, the challenge extends beyond selecting climate-resilient trees. Nine species fall short of fostering the biodiversity necessary for stable mixed forests. “Mixed forests, featuring various species, enhance ecosystem resilience against disturbances like bark beetles. However, Europe faces a shortage of suitable species for creating diverse mixed forests,” explained publication co-author Prof. Rupert Seidl.

Trees are instrumental for their carbon storage capability, as habitats for wildlife, and as a source of timber. However, not all species are equally proficient in these roles. Only three of the "trees of the future" identified by the researchers exhibit promising functionalities.