08.09.2026 | Cédric Angehrn | WSL News
Two key objectives of forestry are timber production and biodiversity. How these two can be reconciled is the focus of the Forest Dialogue 2026, taking place on 10 September in Basel. A few questions for Arthur Gessler, head of SwissForestLab.
- The more diverse the forest, the greater the chance that it will be able to cope with changing environmental conditions.
- Diverse forests, for example, are better able to withstand water shortages.
- At the Forest Dialogue 2026, representatives from science, politics and practice will exchange knowledge and learn from one another.
Mr Gessler, what do you mean by sustainable timber production?
Timber production is sustainable if it actively addresses the uncertainties of the future, mitigates potential risks to some extent, and then creates conditions under which timber can still be harvested from forests. In the past, forestry planning was more predictable than it is today. Foresters could consult their growth tables and thus knew how their stands would develop over time. Those days are gone: climate change is making it increasingly difficult to predict how forests will develop. In order to manage stable commercial forests, the forestry sector needs new approaches.
Is biodiversity key to this?
Exactly – promoting biodiversity is one way of dealing with uncertainty. Increased biodiversity acts as a kind of safeguard. If we have different tree species in the forest, the likelihood that some of them will be able to cope with changing environmental conditions is much higher than if we have only a few species or even a monoculture. Forestry operations can promote biodiversity, for example, by taking more active measures at certain sites so that tree species that require light and those that tolerate shade can coexist. They are also increasingly planting tree species that are thought to be well-suited to coping with future conditions at the respective site.
How does greater biodiversity make the forest more resilient?
At present, our forests are increasingly exposed to drought and heat. We know that a species-rich forest is significantly better able to cope with water scarcity. This is because different species develop roots at different depths. In this way, the trees absorb the water present in the soil far more efficiently than if they all had roots in the same soil layer. The deep-rooted oak, for example, transports water upwards from deeper soil layers. It absorbs some of this water itself, whilst releasing some into the dry topsoil. Trees with shallower roots, which would otherwise suffer from drought stress, can then make use of this water.
What are your hopes for the Forest Dialogue in Basel?
Science, practice and policy come together on an equal footing and are given the opportunity to fill each other’s knowledge gaps. The aim is for everyone to learn from one another. Whilst science can formulate general principles for sustainable forest management, it cannot guarantee that these will work equally well in every single location. This is where we researchers can learn from foresters. Conversely, we can support foresters when their practical experience is no longer sufficient because environmental conditions are changing. We have models and methods such as the Tree App (tree-app.ch), which can be used to select sustainable tree species for a wide variety of sites.
Contact ¶
Links ¶
- You can find further information about the event here: Forest Dialogue 2026
- You can find a link to sign up here: Registration Forest Dialogue 2026
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