TOOLS-FOR-ADAP

Coordinating institution: CNRS
Partner institutions: INRAE | Office National de Forêts | Sorbonne Université | Université Claude Bernard Lyon 1
Project leaders: Isabelle Chuine (CNRS)
Project duration:48 mois | 1 octobre 2025 → 30 septembre 2029

The recent massive dieback of forests in many European regions underlines the urgent need for strategic guidance on forest management practices. Beech and oak forests represent one third of the surface area of the French metropolitan forest. Beech forests show general decline and regeneration problems throughout France. Sessile oak forests, although considered more resilient to climate change, are also experiencing worrying health and regeneration problems. Effective strategic management guidance in such a dramatic context is hampered by significant gaps in our in-depth understanding of key ecological and evolutionary questions: What drives tree reproductive patterns and inter-individual susceptibility to drought? Is the currently available phenotypic and genetic variance across the species range sufficient to drive natural selection or assisted genetic enrichment?

Tree fitness determines forest regeneration capacity, resilience and adaptation to global warming, and depends on key traits related to drought resistance and phenology (the timing of bud burst, flowering, fruit ripening and leaf senescence). Drought strongly influences tree and seedling survival, while phenology influences resource acquisition and allocation to fruit production and growth.

Beech and sessile oak are particularly interesting to compare from a scientific point of view, not only because they face important dieback and regeneration problems, but also because they have very different ecological strategies. Their comparison offers a promising way to elucidate the environmental and genetic components of fruiting dynamics, phenological traits and drought resistance traits. Beech and oak have different fruiting patterns: beech has cyclic, synchronised fruiting every two years, whereas oak patterns are unpredictable with limited synchrony. Beech phenology is regulated by both temperature and photoperiod, unlike oak, which relies solely on temperature. Beech is also more susceptible to drought, although the reasons for this susceptibility remain unclear despite recent research advances.

In order to provide forest managers with operational guidelines for improved regeneration practices and genetic enrichment plans for beech and sessile oak forests in the next decade, TOOLS-FOR-ADAP proposes to

1. Quantify and characterize the standing diversity of traits related to phenology, interannual flowering and fruiting dynamics and drought resistance,
2. Acquire essential knowledge on the environmental and genetic determinants of these traits,
3. Quantify and characterize the genetic diversity of these traits to establish gene pools that could be used for future forest enrichment programs.

To achieve these objectives, TOOLS-FOR-ADAP brings together teams with expertise in forest monitoring using imaging technology, machine learning, genomics, ecophysiology and ecological modelling, and proposes to:

1. Develop a method to rapidly and reliably monitor the phenology, water status and fecundity of individual trees in natural forests based on UAV image acquisition and artificial intelligence;
2. Screen several forests for diversity in phenology, fecundity and water stress,
3. Identify the genetic factors involved in phenology, drought stress and fruiting patterns by conducting a population genomics survey using new two-dimensional GWAS-Genome Wide Association Studies- extending genotyping to structural variants,
4. Transfer to forest managers newly developed methods of forest monitoring using UAVs and a tool for predicting fruit load in beech and oak forests.

The results will also strengthen the calibration and validation of models developed in two other starting projects. These models will explore whether phenotypic and genetic variations in beech and oak forests will be sufficient for their adaptation to future climatic conditions and potentially be used to produce guidelines for genetic enrichment programs to accelerate natural selection and adaptation.