As climate change accelerates, Europe’s forests are under increasing stress. European beech (Fagus sylvatica), a dominant and ecologically important tree species, has been especially harmed by recent droughts, including the severe event of 2018 that caused widespread dieback across Switzerland but also in other parts of Europe. While some individuals or populations appear more resilient, we still do not know why this variability exists.

In the first week of April, more than 20 researchers and practitioners from Switzerland and Europe met at the University of Zurich’s Department of Geography for a one-day workshop on the future of beech forests. We discussed the current state of research on the spatial distribution of genomic variation in beech and how this diversity might shape the species’ resilience to drier and hotter climates. 

Sharing knowledge from genomics, ecology, and forest science

Discussions ranged from studies of genetic diversity in natural and experimental forests, to technical challenges in sequencing, to the practical needs of forest managers. A central theme was the importance of intraspecific genetic variation—the diversity found within a species—which appears a key factor in climate adaptation.

^{In the lunch break we introduced all workshop participants to our two common garden experiments
at Irchel Campus. (Image: Ting Tang)}

Genetic patterns and practical implications

Several speakers presented ongoing work and recent findings. For example, the new finding that some tree seed families perform better in diverse forests, while others thrive in monocultures, could guide reforestation strategies. Furthermore, genetic variation in beech may be more individual-based than population-based, raising questions about how we manage seed sourcing and assisted gene flow. Although field and lab studies have identified regions of the genome that may contribute to drought tolerance, linking these regions to long-term tree performance remains challenging. Compared to oak, beech appears to rely more on phenotypic plasticity—a tree’s ability to adjust to conditions without genetic change.

In the afternoon, we discussed broader themes in three breakout groups:

• Forestry perspectives: While beech is widespread, its economic value is modest, and there are concerns about the long-term survival of seedlings under changing conditions. Still, foresters see potential, especially with tools for quickly assessing tree quality and promoting diverse, resilient forests.
• Genomic tools and data gaps: We discussed the need for better genomic resources and sequencing methods tailored to plants. The emerging pangenome and more affordable sequencing approaches may soon help bridge key data gaps.
• How to make forests more resilient: A consensus emerged that assessing beech resilience requires coordinated, long-term studies across ecological gradients, better trait and fitness data, and experimental trials to link genotypes to real-world outcomes.

The future of beech forests depends on integrating genomic insights with ecological data and management practices. To enable forests to persist and thrive under climate change, we need more collaboration, better tools, and a focus on the traits and processes.

Sofia van Moorsel, Spatial Genetics