Long-term monitoring of forests reveals a progressive decrease in tree health worlwide, mostly due to climate change, which ultimately leads to forest loss. European forests are no exception and there is a growing concern about the ability of major ecosystems such as oak and pine forests, to withstand more frequent and intense droughts, heat waves and fires. Declining trees become more vulnerable to pests (such as pine wood nematode), diseases (such as acute oak disease or red band needle blight on pines) and  forest fires. As tree dieback, many valuable services are gradually lost: for instance, oak wood – prized for its hardness and durability - has been used for centuries in construction and for making wine and spirit barrels. Oak trees also hold cultural significance across Europe and provide habitats for a large portion of forest biodiversity. Forest as a whole act as carbon sinks. Foresters urgently need real-time tools to monitor the health of their forests. Satellites and drones combined with new image analysis algorithms such as AI offer new opportunities in complementary ways to achieve this goal. However, significant challenges remain, including the complexities of mixed, multi-layered forest with varying degree of foliage porosity, and forest practices such as cutting.

Beyond the early detection of dieback areas, identifying the factors underlying this phenomenon is crucial to prevent, or at least delay as much as possible, tree dieback. Factors such as tree species/genetics, density, age, mixture, soil type, temperatures, precipitations, have been identified, but their respective importance in a given place is still unclear, particularly for factors that foresters can influence. Improving our understanding on the trajectories leading to forest dieback is essential for developing  forest management practices that enhance forest resistance to climate change.

Forest regenerate either naturally from mature seeding trees within the stands or through plantations. Harsher climatic conditions, especially during summer, can cause high mortality rate among seedlings and young plants. New approaches aimed at preserving more buffered climatic conditions, e.g. regenerating or planting in small gaps, seem promising but needs to prove their efficiency from an ecological, practical and economical perspective. Additionally, large ungulates may jeopardize forest regenerations.

Current field observations align with modelling studies, suggesting that future climatic conditions may exceed the phenotypic plasticity and evolutionary responses of most trees within part of their current ranges. As a result, the distribution of most European trees is likely to be dramatically affected over the next decades. There is an ongoing intense scientific debate regarding whether tree populations will be able to adapt to future climatic conditions or not. Consequently,  foresters are considering planting new forest genetic resources, such as provenances or species growing in conditions similar to those predicted for the next century. Auto-ecological studies, common gardens and participatory approaches - among others - help assessing the potential of various genetics to cope with climate change.

Climate change is already strongly impacting European oak and pine forests, necessitating the exploration and adoption of new practices that show promising results. Meanwhile, forest stakeholders and the general public (who are increasingly opposed to forest cuttings) must  adapt and accept the inevitable changes in managed forests. New approaches of deliberating are needed to facilitate exchanges and find compromises.

The objectives of this symposium, funded by the Sycomore ARD CVL Programme cover the following topics:

• Monitoring forest health from ground to space
• Identifying factors contributing to forest dieback
• Assessing the consequences of forest dieback on tree growth, forest functioning, biodiversity and forest hazards
• Managing forest affected by tree dieback
• Identifying new genetics varieties better suited for future climatic conditions
• Adapting regeneration and planting practices to increases their success
• Exploring professional and citizen’s perspectives on the impact of climate change on forest and their own adaptation strategies for future challenges

While this symposium will mostly consider oaks and pines, contributions about other species are also welcome.