Dear colleagues,

We are pleased to invite you to the FORESTT international conference: FORESTs and global environmental changes: social-ecological systems in Transition. https://forestt-international-conference.colloque.inrae.fr/ which will take place in October 5 to 7, 2027 in Metz (France). The conference is organized by the PEPR FORESTT (French research program on Forest resilience), coordinated by the National Research Institute for Agriculture, Food and Environment (INRAE), under the auspices of Research Groups and Task Forces of the International Union of Forest Research Organizations (IUFRO), with involvement of voluntary regional, national, European or international research initiatives in the field of social-ecological forest system resilience.

Specifically, we would like to bring your attention to the symposium Tree-microbe interactions in forest health and disease. The abstract submission is now open: https://forestt-international-conference.colloque.inrae.fr/scientific-program/symposiums The submission deadline is December 13, 2026.

Symposium abstract:

Global forest ecosystems face dieback and mortality events that compromise biodiversity, productivity, and essential ecosystem services. On the one hand, chronic dieback events with a marked biotic component are increasingly frequent. On the other hand, the emergence of new diseases is also exponentially increasing. Those can be driven by the introduction of exotic pathogens, but also by climate change and evolutionary shifts in pathogen virulence, which can trigger outbreaks of native pathogens. Together, these processes are often the underlying causes of widespread forest decline worldwide.

Tree-associated microbiota play a crucial role in host adaptation to environmental change and biotic stress. By extending the functional phenotype of their host, these microbial communities enhance nutrient and water acquisition, modulate physiological stress responses, and contribute to protection against pathogens. Despite growing recognition of these functions, much of our current understanding of host–microbiome–pathogen interactions derives from studies on model organisms and agricultural systems. In contrast, forest tree species and their complex microbial consortia remain comparatively understudied, even as research at the interface between tree health, disease expression, and the tree microbiome is rapidly expanding.

These advances highlight the need to move beyond traditional single-host-single-pathogen frameworks toward more integrative perspectives on forest disease. Increasing evidence highlights the prevalence of complex forest diseases involving multiple interacting organisms, including intra- and cross-kingdom assemblages (fungi, oomycetes, bacteria and/or viruses). These interactions are often intensified by abiotic stressors such as drought, underscoring the necessity of integration of environmental stress into disease ecology.

This symposium aims to explore mechanisms underlying tree and forest dieback from a multidimensional perspective that integrates tree-microbe and microbe-microbe interactions.

We particularly welcome contributions addressing:

• the role of microbiota in modulating tree disease expression,
• microbiome-mediated susceptibility or resilience to forest dieback,
• tripartite interactions between drought, pathogens, and tree-associated microbiota,
• the ecology of complex forest diseases.

By bringing together expertise across forest pathology, microbial ecology and climate-related stress, this symposium seeks to advance a holistic understanding of forest health.

Symposium organizers:

Mireia Gómez-Gallego (INRAE, France)

Aurélie Deveau (INRAE, France)

Jaime Aguayo (ANSES, France)

Jonàs Oliva (UdL, CTFC, Spain)

Two more symposium will be hold on biotic interactions and forest health:

• Multitrophic interactions in forest soils: How to bridge biodiversity and functions in a global change context?
• Pine wilt disease: A multidisciplinary approach to an ongoing crisis

You can also browse the conference website for the themes:

Theme 1: Forest Ecological & Evolutionary Processes

Theme 2: Biotic Interactions & Forest Health

Theme 3: Monitoring, Modelling & Data Integration

Theme 4: Forest Management, Disturbances & Adaptation

Theme 5: Social-Ecological Forest Systems, Governance & Bioeconomy

Theme 6: Science, Policy & Education

We would be grateful if you could forward this email to any colleagues who might be interested.

We hope you find this proposal appealing, and we look forward to welcoming you all to France.

Best regards,

Mireia on behalf of the symposium organizers.