Modeling assisted migration to adapt forests to climate change

#RestorationStory by Debojyoti Chakraborty

Did you know that forest trees have evolved at species and population levels to adapt to the local environment in which they grow? Such local adaptations lead to genetically differentiated populations, with traits that enable them to adapt to biotic and abiotic stress factors. Climate change is likely to exert tremendous pressure on forests and their ecosystem services. As the climate changes, forest tree populations are likely to respond in three possible ways: adapt, migrate, or become locally extinct. Natural migration and adaptation are slow processes that cannot keep up with this rapidly changing climate and would result in maladapted tree populations in the future, with reduced capacity to provide multiple ecosystem services. Given the limitations in natural tree migration and rapid adaptation, researchers have realized that we need human-facilitated realignment to match the populations to the environment to which they are adapted. Such facilitated movement is commonly referred to as assisted migration, assisted colonization, assisted relocation, or facilitated migration. On a practical level, such strategies include the choice of adapted species and seed sources. We can use provenance trials where several seed sources of a tree species are planted under a common environment. These offer a unique opportunity to model tree species and their population’s response to climate change. Such models include species distribution models, and response functions.

Our summer school on assisted migration

We, a team of researchers from the Austrian Research Center for Forests (BFW, Vienna) recently hosted a six-day summer school aiming at providing in-depth insight into the concept of assisted migration of forests under climate change, and with a focus on models to guide decision support.

The summer school was organized in collaboration with The EVOLTREE network and the Czech University of Life Sciences (CZU) and took place at the Forestry Training Center at Traunkirchen from July 30 to August 4, 2023. We broadly discussed several topics including climate change and its effects on European forests, options for adaptation and mitigation, and the importance of genetic diversity. We also explored ways of incorporating genetic diversity in decision-making, especially data sources for developing models for assisted migration, provenance trial history and current use, and elaborated the current discourse on assisted migration, challenges, and opportunities.

One of the objectives was to familiarize the 23 participants from across Europe and Australia with different concepts of modeling on assisted migration, issues on genetic diversity, and climate change. Later, the participants analyzed real-time provenance trial data which were systematically provided by BFW and developed their models showcasing seed transfer under climate change.

Outdoor Activities – from seedlings to hiking and homebrewed beer

As part of the summer school we organized an excursion to visit LIECO forest nurseries and provenance trials in St-Martin Austria. LIECO is a forest company producing high-quality containerized forest seedlings in Austria. There, the participants had firsthand experience of planting seedlings and further understanding the process of growing sustainable forest planting materials. This was followed by a hike to a traditional Alpine Hut (Alm-Hochstein) where we exchanged ideas over homebrewed beer and lip-smacking food. Finally, the perfect location of Traunkirchen by the beautiful Traun lake offered many recreational opportunities for both the participants and the organizers.

Ash dieback and its consequences on genetic diversity

Check out the videos of the EUFORGEN Webinar Series

Rising temperatures across Europe, extreme weather events, higher fire risk or increased vulnerability to biotic disturbances such as pests and diseases are some of the consequences of climate change on forests. In the case of biotic outbreaks, scientists have been investigating how to make tree populations more resilient from a genetic perspective and to understand alternatives for tree conservation in case of diseases or pests.

To further explore this issue and understand today’s scientific advances, the EUFORGEN Secretariat organised in February a webinar series entitled “Biotic outbreak management of the Genetic Conservation Units Network: case study on ash dieback”, which consisted of three online sessions open to the public. The virtual sessions featured a panel of researchers and scientific experts to examine the specific problem of ash dieback in Europe from different angles.

You can find more info on the series including the videos here.


Featured image via Pixabay