The extent to which beech will be affected by the end of the century, and in which locations, will depend on the course of climate change © Ulrich Wasem WSL
The future of the beech in Europe does not look rosy. Climate change will have a massive impact on this species, too. This is the conclusion researchers at the WSL came to. “Beech trees will not only lose dominance and area in marginal locations where it already does not find optimal conditions, but also in large parts of its Central European growing area,” lead author of the study and WSL researcher Prof. Dr. Arthur Gessler from the Department of Environmental Systems Science at the ETH Zurich says. The tree species will suffer especially from the increasingly extreme dry years. “Drought can cause the crown to partially die, which often results in the death of the tree as a whole the following year,” Gessler explains.
The new study, “Back to the future – A new look at the prospects for beech after 20 years of research and advancing climate change”, is based on two publications from 2004 and 2005, which came to divergent conclusions. One team of researchers predicted a severe threat to beech by the end of the 21st century, even in the core of its current growing area. The other team did not see this danger – or only in areas already at risk of drought today – and warned against causing uncertainty among public and private forest owners.
Better data
The 2018 drought hit beech trees hard. Not all trees recovered from it. Very often, leaves are already changing color in June © Ulrich Wasem
“Today, we now know a lot more about the effects of climate change on the vitality, growth, stress resistance and competitiveness of beech trees than we did then, and we can therefore make more accurate predictions about their future potential,” Arthur Gessler comments. “Using this new knowledge, we were able to thoroughly re-examine those previous studies.”
Over the years, the data situation has improved considerably. In addition, the effects of climate change on beech forests (and forests in general) are much more tangible today than they were twenty years ago and are no longer just the subject of scientific controversy. “The extreme years of 2018, 2019, 2020, 2022 and, partially, 2023 have caused visible and massive damage to the trees, which gives a good idea of future developments,” Gessler analyzes. Specifically, this means that the trees will no longer be able to regenerate well and will be very vulnerable to extreme events as a result. This could lead to large-scale dieback and a subsequent local extinction of the species.
High diversity helps
The extent of the impact on beech trees and the locations affected by the end of the century will depend on the course of climate change and, ultimately, on the success of measures implemented to reduce global carbon emissions. “From today’s perspective, it is clear that beech will suffer even if CO2 emissions are significantly reduced, i.e. assuming a rather optimistic climate change scenario,” Gessler says.
For this reason, Gessler believes that the forestry industry must prepare itself for fundamental changes. “To prepare forests for the future, drought- and heat-tolerant tree species such as oak should be introduced into stands as well”, Gessler says. High diversity in terms of structures and tree species, but also genetic diversity in beech, could help achieve that. In the worst case – even if the beech were to suffer massive damage due to drought – drought-resistant tree species would survive and thus at least prevent a total loss.
