Hendrik Davi

French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · URFM

The fundamental trade‐off between current and future reproduction has long been considered to result in a tendency for species that can grow large to begin reproduction at a larger size. Due to the prolonged time required to reach maturity, estimates of tree maturation size remain very rare and we lack a global view on the generality and the shape...

Global radiation is a key climate input in forest process-based models (PBM) as it determines photosynthesis, transpiration and the canopy energy balance. While radiation is highly variable at fine spatial resolution in complex terrain due to shadowing effects, data required for PBM currently available over large extents are generally at spatial re...

The recent acceleration of global climate warming has created an urgent need for reliable projections of species distributions, widely used by natural resource managers. Such projections, however, are produced using various modeling approaches with little information on their relative performances under expected novel climatic conditions. Here, we...

In the context of ongoing climate and biodiversity crises, mixed forest stands are increasingly considered as a sustainable management alternative to monocultures. We developed a new individual-based and process-based forest growth model, PDG-Arena, to simulate mixed forest functioning and test ecophysiological interactions among trees in mixed sta...

Key message Phenology is of increasing interest to climate change science and adaptation ecology. Here, we provide bud development, leafing, and leaf senescence data, collected on 772 European beech and silver fir trees between 2006 and 2019 on Mont Ventoux, France. Dataset access is at https://doi.org/10.15454/TRFMZN . Associated metadata are avai...

Severe droughts limit tree growth and forest productivity worldwide, a phenomenon which is expected to aggravate over the next decades. However, how drought intensity and climatic conditions before and after drought events modulate tree growth resilience remains unclear, especially when considering the range-wide phenotypic variability of a tree sp...

Within-population variation in individual tree growth and response to climate has an impact on forest dynamics, resilience and adaptation to environmental change. Combining dendrochronological analyses with a process-based ecophysiological model simulating drought stress at the stand scale, we studied the phenotypic variation of two growth-related...

Aim Our understanding of the mechanisms that maintain forest diversity under changing climate can benefit from knowledge about traits that are closely linked to fitness. We tested whether the link between traits and seed number and seed size is consistent with two hypotheses, termed the leaf economics spectrum and the plant size syndrome, or whethe...

The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundat...

Potential for, and limits to, adaptation to environmental changes are critical for resilience and risk mitigation. The Mediterranean basin is a mosaic of biodiversity-rich ecosystems long affected by human influence, whose resilience is now questioned by climate change. After reviewing the different components of biological adaptation, we present t...

Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250‐fold increase in seed abundance from cold‐dry to warm‐wet climates, driven primarily by...

Since several studies have been reporting an increase in the decline of forests, a major issue in ecology is to better understand and predict tree mortality. The interactions between the different factors and the physiological processes giving rise tree mortality, as well as the inter-individual variability in mortality risk, still need to be bette...

The spatial forest structure that drives the functioning of these ecosystems and their response to global change is closely linked to edaphic conditions. However, the latter properties are particularly difficult to characterize in forest areas developed on karst, where soil is highly rocky and heterogeneous. In this work, we investigated whether ge...

General Context: Climate change can positively or negatively affect abiotic and biotic drivers of tree mortality. Process-based models integrating these climatic effects are only seldom used at species distribution scale. Objective: The main objective of this study was to investigate the multi-causal mortality risk of five major European forest tre...

As part of the 2015 Paris climate agreement and under its Green Deal, the EU proposes to strongly rely on forests for offsetting its carbon footprint. However, planting trees should be avoided in wildfire prone and drought prone habitats, which are expanding significantly as climate warms across Europe. In favorable habitats, tree planting remains...

Mediterranean forests face an intensification of droughts caused by ongoing climate change. To improve our understanding of tree and forest responses to increasing drought, we explored over nine years, the effects of a 30% rainfall exclusion experiment on the water potential, sap velocity and primary and secondary growth of two co-occurring species...

• Key message The increase in climate variability is likely to generate an increased occurrence of both frost-induced and drought-induced damages on perennial plants. We examined how these stress factors can potentially interact and would subsequently affect the vulnerability to each other. Furthermore, we discussed how this vulnerability could be...

Background and Aims Abiotic and biotic stresses related to climate change have been associated with increased crown defoliation, decreased growth and a higher risk of mortality in many forest tree species, but the impact of stresses on tree reproduction and forest regeneration remains understudied. At dry warm margin of species distributions, flowe...

Understanding vegetation response to drought is a major scientific challenge to anticipate and predict changes water dynamics of the zone critique. In this paper, electrical resistivity tomography is used to characterize the spatial variability of soil/subsoil conditions along a forest transect in order to better understand ecophysiological respons...

Climate change (CC) and land use and land cover change (LULCC) threaten Mediterranean forests and the ecosystem services (ES) they provide. In complex socio-ecological systems and under high uncertainties, the resilience of ES has become the target objective for adaptive management strategies driven by decision-makers and local stakeholders. This w...

Aquifer recharge may depend mainly on the difference between precipitation and evapotranspiration. Hydrological models used to estimate groundwater reserves use evapotranspiration models that are mainly determined by climate demand. In particular, mechanisms of plant transpiration are neglected, although transpiration constitutes 70% of evapotransp...

A trade-off between growth and fecundity, reflecting the inability of simultaneously investing in both functions when resources are limited, is a fundamental feature of life history theory. This particular trade-off is the result of evolutionary and environmental constrains shaping reproductive and growth traits, but it remains difficult to pinpoin...

One of the greatest challenges when addressing issues in complex social-ecological systems (SES), is the need for an efficient interdisciplinary framework when large-magnitude social and ecological disturbances occur. Teams comprising of scientists from different backgrounds and disciplines are frequently called upon to propose research methods and...

L’adaptation est un enjeu majeur de la gestion forestière dans le contexte du changement climatique La diversité génétique qui caractérise les arbres forestiers leur confère un potentiel adaptatif très important mais pas illimité Prendre en compte les mécanismes de l’évolution dans les pratiques de gestion forestière adaptative renforcera la capaci...

Three types of process-based models (PBMs) are traditionally used to predict the response of forest tree populations to global change (GC): (i) ecophysiological models, which simulate carbon and water fluxes in forest ecosystems by explicitly integrating the effects of climate and CO2; (ii) forest dynamics models which simulate forest successions b...

Droughts can have strong environmental and socioeconomic impacts in the Mediterranean region, in particular for countries relying on rain-fed agricultural production, but also in areas in which irrigation plays an important role and in which natural vegetation has been modified or is subject to water stress. The purpose of this review is to provide...

One factor that determines a tree’s resilience capacity to drought is its level of interaction with aggravating biotic factors, such as bark beetles, which in turn depends on whether insect populations are at an endemic or epidemic stage. In a Mediterranean natural forest ecosystem, we investigated the ecophysiological characteristics of trees whic...

Plant transpiration is a major component of water fluxes in the critical zone, which needs to be better characterized to improve our ability to understand and model the hydrological cycle. In water-limited ecosystems such as those encountered on karst environments, climate-induced changes in transpiration are expected to be strongly influenced by t...

In species with long‐distance dispersal capacities and inhabiting a large ecological niche, local selection and gene flow are expected to be major evolutionary forces affecting the genetic adaptation of natural populations. Yet, in species such as trees, evidence of microgeographic adaptation and the quantitative assessment of the impact of gene fl...

Many theoretical models predict when genetic evolution and phenotypic plasticity allow adaptation to changing environmental conditions. These models generally assume stabilizing selection around some optimal phenotype. We however often ignore how optimal phenotypes change with the environment, which limit our understanding of the adaptive value of...

Given the multiple abiotic and biotic stressors resulting from global changes, management systems and practices must be adapted in order to maintain and reinforce the resilience of forests. Among others, the transformation of monocultures into uneven-aged and mixed stands is an avenue to improve forest resilience. To explore the forest response to...

Water isotopes from plant xylem and surrounding environment are increasingly used in eco-hydrological studies. Carrière et al. [1] analyzed a dataset of water isotopes in (i) the xylem of three different tree species, (ii) the surrounding soil and drainage water and (iii) the underlying karst groundwater, to understand tree water uptake during drou...

Climate models predict increased drought conditions for the Mediterranean region, putting forests under increasing risk from direct or indirect effects of droughts. On the other hand, increasing CO2 and longer growing seasons could compensate the negative impacts of more intense droughts on forest productivity and carbon sequestration. Furthermore,...

La rapidité du changement climatique (CC) en cours, l’incertitude des modèles climatiques et la diversité des réponses des espèces au CC motivent la communauté scientifique à accroître le volume des observations et à acquérir des données de qualité. Parmi celles-ci, la phénologie du débourrement chez les espèces ligneuses requiert une attention par...

Dans les forêts de montagne, la croissance est limitée à haute altitude par les faibles températures, mais, en région méditerranéenne la sécheresse et les fortes températures constituent aussi un facteur limitant, cette fois-ci à basse altitude. Par ailleurs, peu d'études ont explicitement étudié les effets à court terme (annuel) et à long terme(dé...

The phenology of plants is a major driver of agro-ecosystem processes and biosphere feedbacks to the climate system. Phenology models are classically used in ecology and agronomy to project future phenological changes. With our increasing understanding of the environmental cues affecting bud development, phenology models also increase in complexity...

Inter-individual variability of tree drought responses within a stand has received little attention. Here we explore whether the spatial variations in soil/subsoil properties assessed through electrical resistivity tomography (ERT) could explain variations in drought response traits among trees.  We used ERT to compute the percent variation in res...

Karst environments are unusual because their dry, stony and shallow soils seem to be unfavorable to vegetation, and yet they are often covered with forests. How can trees survive in these environments? Where do they find the water that allows them to survive? This study uses midday and predawn water potentials and xylem water isotopes of branches t...

Drought is a source of stress that affects forest growth, resulting in financial losses for forest owners and amenity losses for society. Due to climate change, such natural events will be more frequent and intense in the future. In this context, the objective of this paper is to compare, from an economic perspective, different forest adaptation st...

Given the multiple abiotic and biotic stressors resulting from global changes, management systems and practices must be adapted in order to maintain and reinforce the resilience of forests. Among others, the transformation of monocultures into uneven-aged and mixed stands is an avenue to improve forest resilience. To explore the forest response to...

Since several studies have been reporting an increase in the decline of forests, a major issue in ecology is to better understand and predict tree mortality. The interactions between the different factors and the physiological processes giving rise tree mortality, as well as the individual variability in mortality risk, still need to be better asse...

Many perennial species, such as trees, show large variations of fruit production between years (the so-called masting) which can have major consequences on forest dynamic and species interactions. Among other drivers of fruit production failure, years of reduced fruit production can be due to the increase of temperature and the resulting advance in...

Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a pr...

L'URFM a participé au colloque BÂTIR DEMAIN AVEC LE PIN D’ALEP: La nouvelle richesse de nos forêts ! qui a eu lieu le vendredi 12 juillet à l'Hotel de Région PACA à Marseille. Cette journée évènement était destiné à l’attention des professionnels et partenaires de la filière forêt-bois, organisée par l’association France Forêt Provence-Alpes-Côte d...

Abiotic and biotic stresses related to climate change have been associated to increased crown defoliation, decreased growth and a higher risk of mortality in many forest tree species, but the impact of stresses on tree reproduction and forest regeneration remains understudied. At dry, warm margin of species distributions, flowering, pollination and...

The adaptation of social-ecological systems such as managed forests depends largely on decisions taken by forest managers who must choose among a wide range of possible futures to spread risks. We used robust decision theory to guide management decisions on the translocation of tree populations to compensate for climate change. We calibrated machin...

Accumulating evidence highlights increased mortality risks for trees during severe drought, particularly under warmer temperatures and increasing vapour pressure deficit (VPD). Resulting forest die-off events have severe consequences for ecosystem services, biophysical and biogeochemical land–atmosphere processes. Despite advances in monitoring, mo...

Modeling studies predict that global warming might severely affect bud dormancy release. However, growing empirical evidences suggest that long photoperiod might compensate for a lack of chilling temperature in photosensitive species. For now, attempts to integrate this effect into models remain limited. Here, we used French budburst phenological r...

Tree ring widths provide very useful information to assess factors controlling tree radial growth and to estimate future growth trajectories under climate change. Radial growth variability has already been lar- gely studied among tree populations that experience different environmental conditions and was most recently analyzed among individuals wit...

A central issue in plant evolutionary ecology is to understand how several coordinated suites of traits (i.e. traits syndrome) may be jointly selected within a single species. This study aims to describe patterns of variation and co‐variation of functional traits in a water‐stressed tree population and test their relationships with performance trai...

(1) This study describes how physiological process-based models can be used to assess the mortality risk of forest trees under global change. (2) Using the CASTANEA model, we simulated the development over time of tree functioning with different ontogenetic and phenotypic characteristics (age, diameter, Leaf Area Index, leaf traits) and growing in...

Assessing underground hydrosystem recharge is crucial to characterizing their hydrogeological functioning. The common questions arising from a poor understanding of hydrogeological mechanism are about parts of the gross rain amount that evapotranspire and get temporarily stored within the soil. Evapotranspiration and soil water storage are largely...

Understanding the determinants of phenotypic variation is critical to evaluate the ability of traits to evolve in a changing environment. In trees, the genetic component of the phenotypic variance is most often estimated based on maternal progeny tests. However, the lack of knowledge about the paternal relatedness hampers the accurate estimation of...

Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2,970 dead and 4,224 living tre...

Assessing underground hydrosystem recharge is crucial to characterizing their hydrogeological functioning. The common questions arising from a poor understanding of hydrogeological mechanism are about parts of the gross rain amount that evapotranspire and get temporarily stored within the soil. Evapotranspiration and soil water storage are largely...

Tree mortality is a key process shaping forest dynamics. Thus, there is a growing need for indicators of the likelihood of tree death. During the last decades, an increasing number of tree-ring based studies have aimed to derive growth–mortality functions, mostly using logistic models. The results of these studies, however, are difficult to compare...

Seed production is a strong indicator of plant fitness and plays a major role in population dynamics. However, the environmental and endogenous factors driving seed production are still poorly described and are often hard to disentangle. Consequently, we combined principal components analysis and mixed-effects linear models that can consider the mu...

Some portions of the porous rock matrix in the karst unsaturated zone (UZ) can contain large volumes of water and play a major role in water flow regulation. The essential results are presented of a local-scale study conducted in 2011 and 2012 above the Low Noise Underground Laboratory (LSBB – Laboratoire Souterrain à Bas Bruit) at Rustrel, southea...