2020 - UMR Silva

[hal-03048264] EUNIS Habitat Classification: Expert system, characteristic species combinations and distribution maps of European habitats

Aim: The EUNIS Habitat Classification is a widely used reference framework for European habitat types (habitats), but it lacks formal definitions of individual habitats that would enable their unequivocal identification. Our goal was to develop a tool for assigning vegetation-plot records to the habitats of the EUNIS system, use it to classify a European vegetation-plot database, and compile statistically-derived characteristic species combinations and distribution maps for these habitats. Location: Europe. Methods: We developed the classification expert system EUNIS-ESy, which contains definitions of individual EUNIS habitats based on their species composition and geographic location. Each habitat was formally defined as a formula in a computer language combining algebraic and set-theoretic concepts with formal logical operators. We applied this expert system to classify 1,261,373 vegetation plots from the European Vegetation Archive (EVA) and other databases. Then we determined diagnostic, constant and dominant species for each habitat by calculating species-to-habitat fidelity and constancy (occurrence frequency) in the classified data set. Finally, we mapped the plot locations for each habitat. Results: Formal definitions were developed for 199 habitats at Level 3 of the EUNIS hierarchy, including 25 coastal, 18 wetland, 55 grassland, 43 shrubland, 46 forest and 12 man-made habitats. The expert system classified 1,125,121 vegetation plots to these habitat groups and 73,188 to other habitats, while 63,064 plots remained unclassified or were classified to more than one habitat. Data on each habitat were summarized in factsheets containing habitat description, distribution map, corresponding syntaxa and characteristic species combination. Conclusions: EUNIS habitats were characterized for the first time in terms of their species composition and distribution, based on a classification of a European database of vegetation plots using the newly developed electronic expert system EUNIS-ESy. The data provided and the expert system have considerable potential for future use in European nature conservation planning, monitoring and assessment.

ano.nymous@ccsd.cnrs.fr.invalid (Milan Chytrý) 09 Dec 2020

https://hal.science/hal-03048264v1

[hal-03048253] Vegetation unit assignments: phytosociology experts and classification programs show similar performance but low convergence

Aims: Assigning vegetation plots to vegetation units is a key step in biodiversity management projects. Nevertheless, the process of plot assignment to types is usually non-standardized, and assignment consistency remains poorly explored. To date, the efficiency of automatic classification programs has been assessed by comparing them with a unique expert judgment. Therefore, we investigated the consistency of five phytosociology expert judgments, and the consistency of these judgements with those of automatic classification programs. Location: Mainland France. Methods: We used 273 vegetation plots distributed across France and covering the diversity of the temperate and mountainous forest ecosystems of Western Europe. We asked a representative panel of five French organizations with recognized expertise in phytosociology to assign each plot to vegetation units. We provided a phytosociological classification including 228 associations, 43 alliances and eight classes. The assignments were compared among experts using an agreement ratio. We then compared the assignments suggested by three automatic classification programs with the expert judgments. Results: We observed small differences among the agreement ratios of the expert organizations; a given expert organization agreed with another one on association assignment one time in four on average, and one time in two on alliance assignment. The agreement ratios of the automatic classification programs were globally lower, but close to expert judgments. Conclusions: The results support the current trend toward unifying the existing classifications and specifying the assignment rules by creating guiding tools, which will decrease inter-observer variation. As compared to a pool of phytosociology experts, programs perform similarly to individual experts in vegetation unit assignment, especially at the alliance level. Although programs still need to be improved, these results pave the way for the creation of habitat time series crucial for the monitoring and conservation of biodiversity.

ano.nymous@ccsd.cnrs.fr.invalid (Lise Maciejewski) 03 May 2022

https://hal.science/hal-03048253v1

[hal-02434220] TRY plant trait database – enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration , biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

ano.nymous@ccsd.cnrs.fr.invalid (Jens Kattge) 09 Nov 2020

https://amu.hal.science/hal-02434220v1

[hal-02650649] Long-term thermal sensitivity of Earth’s tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate.

ano.nymous@ccsd.cnrs.fr.invalid (Martin J P Sullivan) 17 Aug 2024

https://hal.umontpellier.fr/hal-02650649v1

[hal-03778635] The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

The FLUXNET2015 dataset provides ecosystem-scale data on CO 2 , water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.

ano.nymous@ccsd.cnrs.fr.invalid (Gilberto Pastorello) 16 Sep 2022

https://hal.science/hal-03778635v1

[hal-02996232] Unraveling the relative role of light and water competition between lianas and trees in tropical forests

Despite their low contribution to forest carbon stocks, lianas (woody vines) play an important role in the carbon dynamics of tropical forests. As structural parasites, they hinder tree survival, growth and fecundity; hence, they negatively impact net ecosystem productivity and long-term carbon sequestration. Competition (for water and light) drives various forest processes and depends on the local abundance of resources over time. However, evaluating the relative role of resource availability on the interactions between lianas and trees from empirical observations is particularly challenging. Previous approaches have used labour-intensive and ecosystem-scale manipulation experiments, which are infeasible in most situations. We propose to circumvent this challenge by evaluating the uncertainty of water and light capture processes of a process-based vegetation model (ED2) including the liana growth form. We further developed the liana plant functional type in ED2 to mechanistically simulate water uptake and transport from roots to leaves, and start the model from prescribed initial conditions. We then used the PEcAn bioinformatics platform to constrain liana parameters and run uncertainty analyses. Baseline runs successfully reproduced ecosystem gas exchange fluxes (gross primary productivity and latent heat) and forest structural features (leaf area index, aboveground biomass) in two sites (Barro Colorado Island, Panama and Paracou, French Guiana) characterized by different rainfall regimes and levels of liana abundance. Model uncertainty analyses revealed that water limitation was the factor driving the competition between trees and lianas at the drier site (BCI), and during the relatively short dry season of the wetter site (Paracou). In young patches, light competition dominated in Paracou but alternated with water competition between the wet and the dry season on BCI according to the model simulations. The modelling workflow also identified key liana traits (photosynthetic quantum efficiency, stomatal regulation parameters, allometric relationships) and processes (water use, respiration, climbing) driving the model uncertainty. They should be considered as priorities for future data acquisition and model development to improve predictions of the carbon dynamics of liana-infested forests. Synthesis. Competition for water plays a larger role in the interaction between lianas and trees than previously hypothesized, as demonstrated by simulations from a process-based vegetation model.

ano.nymous@ccsd.cnrs.fr.invalid (Félicien Meunier) 09 Nov 2020

https://hal.science/hal-02996232v1

[hal-02948750] Validation of Space-based albedo products from upscaled tower-based measurements over Heterogeneous and Homogeneous landscapes

Surface albedo is a fundamental radiative parameter as it controls the Earth’s energy budget and directly affects the Earth’s climate. Satellite observations have long been used to capture the temporal and spatial variations of surface albedo because of their continuous global coverage. However, space-based albedo products are often affected by errors in the atmospheric correction, multi-angular bi-directional reflectance distribution function (BRDF) modelling, as well as spectral conversions. To validate space-based albedo products, an in situ tower albedometer is often used to provide continuous “ground truth” measurements of surface albedo over an extended area. Since space-based albedo and tower-measured albedo are produced at different spatial scales, they can be directly compared only for specific homogeneous land surfaces. However, most land surfaces are inherently heterogeneous with surface properties that vary over a wide range of spatial scales. In this work, tower-measured albedo products, including both directional hemispherical reflectance (DHR) and bi-hemispherical reflectance (BHR), are upscaled to coarse satellite spatial resolutions using a new method. This strategy uses high-resolution satellite derived surface albedos to fill the gaps between the albedometer’s field-of-view (FoV) and coarse satellite scales. The high-resolution surface albedo is generated from a combination of surface reflectance retrieved from high-resolution Earth Observation (HR-EO) data and moderate resolution imaging spectroradiometer (MODIS) BRDF climatology over a larger area. We implemented a recently developed atmospheric correction method, the Sensor Invariant Atmospheric Correction (SIAC), to retrieve surface reflectance from HR-EO (e.g., Sentinel-2 and Landsat-8) top-of-atmosphere (TOA) reflectance measurements. This SIAC processing provides an estimated uncertainty for the retrieved surface spectral reflectance at the HR-EO pixel level and shows excellent agreement with the standard Landsat 8 Surface Reflectance Code (LaSRC) in retrieving Landsat-8 surface reflectance. Atmospheric correction of Sentinel-2 data is vastly improved by SIAC when compared against the use of in situ AErosol RObotic NETwork (AERONET) data. Based on this, we can trace the uncertainty of tower-measured albedo during its propagation through high-resolution EO measurements up to coarse satellite scales. These upscaled albedo products can then be compared with space-based albedo products over heterogeneous land surfaces. In this study, both tower-measured albedo and upscaled albedo products are examined at Ground Based Observation for Validation (GbOV) stations (https://land.copernicus.eu/global/gbov/), and used to compare with satellite observations, including Copernicus Global Land Service (CGLS) based on ProbaV and VEGETATION 2 data, MODIS and multi-angle imaging spectroradiometer (MISR).

ano.nymous@ccsd.cnrs.fr.invalid (Rui Song) 25 Oct 2023

https://hal.inrae.fr/hal-02948750v1

[hal-03045938] Natura 2000 forest habitats: climatic debt in lowlands and thermophilization in highlands

Natura 2000 is a European network of sites dedicated to the conservation of vulnerable habitats. The definitions of Natura 2000 habitats are mainly based on plant communities. We investigated if the increase of the dominance of warm-adapted species observed in plant communities, described as thermophilization, had already led to measurable changes in Natura 2000 forest habitats. We created 5701 pairs of neighboring forest plots by gathering plots surveyed before 1987 and after 1997 to reflect historical and recent climatic conditions. A Natura 2000 habitat type was assigned to each vegetation plot using an automatic classification program. We calculated a temperature index that synthesized the temperature range of each habitat, and compared the habitat temperature indexes of the recent and historical plots of each pair. We highlighted a significant overall shift of 4.8% ± 1.78 (CI 95%) of the pairs toward warmer habitats over the studied period. While the shift was not significant in lowlands, 11.1% ± 3.0 (CI 95%) of the pairs evolved toward warmer habitats in highlands. The excess of pairs with a warmer habitat in the recent period was interpreted as thermophilization of Natura 2000 forest habitats. Therefore, global warming has been strong enough to induce actual changes at the coarse-grained habitat resolution specifically targeted by public policies. The absence of significant results in lowlands suggests the existence of unrealized potential habitat changes, which can be considered as a climatic debt. These results call for differential prioritization levels and implementations of public policies for nature conservation in lowlands and highlands.

ano.nymous@ccsd.cnrs.fr.invalid (Lise Maciejewski) 21 Apr 2023

https://hal.science/hal-03045938v1

[hal-02948795] A portable, low-cost relaxed eddy accumulation (REA) system for quantifying ecosystem-level fluxes of volatile organics

Quantification of biogenic volatile organic compound (BVOC) fluxes into the atmosphere is crucial to understand their role in atmospheric oxidation and biogeochemical cycles. BVOC flux measurements were carried out in nine forest ecosystems using a relaxed eddy accumulation (REA) based sampling system, which is easily transportable, simple to operate and designed to be low-cost and therefore can easily be deployed at multiple remote locations. The REA measurements were carried out during daytime between 06:00 and 18:30 (Local Time) with a flux averaging period of 30 min. A detailed description of the REA sampling setup, operational procedure and validation by comparison with full eddy covariance (EC) BVOC flux measurements is provided. BVOC flux measurements from established long-term carbon and water flux tower sites in nine forest ecosystems are compared including Manitou Forest Observatory in Colorado, USA (pine woodland forest), Niwot Ridge AmeriFlux site in Colorado, USA (subalpine forest), Deer Canyon Preserve in New Mexico, USA (pinyon-juniper forest), Lei bamboo forest site near Taihuyuan, China, Qianyanzhou ChinaFLUX site in China (pine forest), Baskett Wildfire Refuge MOFlux site in Missouri, USA (deciduous oak forest), University of Michigan Biological Station PROPHET site in Michigan, USA (mixed deciduous forest), Changbai Mountain Forest Research Station in China (mixed deciduous forest) and the Guyaflux site (GF-Guy) in French Guiana (tropical rainforest). BVOC flux measurements using our REA setup confirm dominance of 2,3,2- methylbutenol (2,3,2-MBO) at the Manitou Forest Observatory and Niwot Ridge sites in Colorado. Monoterpene fluxes measured by REA showed good agreement (within ±10%) with monoterpene fluxes measured by PTR-MS at the Manitou Forest Observatory. The MOFlux site in Missouri was dominated by isoprene emissions (average flux of ~ 9.5 mg m−2 h−1) whereas the Deer Canyon site was dominated by α-pinene emissions (average flux ~ 0.73 mg m−2 h−1). Mixed deciduous forest sites at the PROPHET Station in Michigan and Changbai Mountain Forest Research Station in China primarily emitted isoprene along with some α-pinene, β-pinene and d-Limonene. Isoprene and α-pinene were the dominant BVOCs emitted from the subtropical Lei bamboo plantation at the Taihuyuan site in China while the pine forest site at Qianyanzhou in China were dominated by α-pinene emissions along with significant isoprene. BVOC measurements across different seasons (during 2009–2011) at a tropical forest site in French Guiana (Guyaflux site) revealed the dominance of isoprene emissions during all seasons. Irrespective of the type of the forest ecosystem, α-pinene was among the dominant monoterpenes emitted from all nine forests.

ano.nymous@ccsd.cnrs.fr.invalid (Chinmoy Sarkar) 31 Aug 2021

https://hal.inrae.fr/hal-02948795v1

[hal-02948749] The global distribution of leaf chlorophyll content

Leaf chlorophyll is central to the exchange of carbon, water and energy between the biosphere and the atmosphere, and to the functioning of terrestrial ecosystems. This paper presents the first spatially-continuous view of terrestrial leaf chlorophyll content (Chl(Leaf)) at the global scale. Weekly maps of Chl(Leaf) were produced from ENVISAT MERIS full resolution (300 m) satellite data using a two-stage physically-based radiative transfer modelling approach. Firstly, leaf-level reflectance was derived from top-of-canopy satellite reflectance observations using 4-Scale and SAIL canopy radiative transfer models for woody and non-woody vegetation, respectively. Secondly, the modelled leaf-level reflectance was input into the PROSPECT leaf-level radiative transfer model to derive Chl(Leaf). The Chl(Leaf) retrieval algorithm was validated using measured Chi(Leaf) data from 248 sample measurements at 28 field locations, and covering six plant functional types (PFTs). Modelled results show strong relationships with field measurements, particularly for deciduous broadleaf forests (R-2 = 0.67; RMSE = 9.25 mu g cm(-2); p < 0.001), croplands (R-2 = 0.41; RMSE = 13.18 mu g cm(-2); p < 0.001) and evergreen needleleaf forests (R-2 = 0.47; RMSE = 10.63 mu g cm(-2); p < 0.001). When the modelled results from all PFTs were considered together, the overall relationship with measured Chl(Leaf )remained good (R-2 = 0.47, RMSE = 10.79 mu g cm(-2); p < 0.001). This result is an improvement on the relationship between measured Chl(Leaf) and a commonly used chlorophyll-sensitive spectral vegetation index; the MERIS Terrestrial Chlorophyll Index (MTCI; R-2 = 0.27, p < 0.001). The global maps show large temporal and spatial variability in Chl(Leaf), with evergreen broadleaf forests presenting the highest leaf chlorophyll values, with global annual median values of 54.4 mu g cm(-2). Distinct seasonal Chl(Leaf) phenologies are also visible, particularly in deciduous plant forms, associated with budburst and crop growth, and leaf senescence. It is anticipated that this global Chl(Leaf) product will make an important step towards the explicit consideration of leaf-level biochemistry in terrestrial water, energy and carbon cycle modelling.

ano.nymous@ccsd.cnrs.fr.invalid (H. Croft) 25 Oct 2023

https://hal.inrae.fr/hal-02948749v1

[hal-03038558] Dernières innovations sur la plantation forestière. Contribution de la R&D pour accompagner les évolutions attendues dans les pratiques

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ano.nymous@ccsd.cnrs.fr.invalid (Catherine C. Collet) 03 Dec 2020

https://hal.inrae.fr/hal-03038558v1

[hal-02963149] Le profil cultural : une méthode d'observation pour analyser les impacts de la préparation mécanisée du site sur la structure du sol

Face à la problématique du renouvellement forestier en stations contraignantes, la R&amp;D s’attache à concevoir, tester et évaluer des techniques appropriées de préparation mécanisée du sol avant plantation. L’évaluation s’appuie légitimement sur la survie et la croissance des plants. Mais pour interpréter les résultats, il faut aussi pouvoir caractériser et analyser les effets sur le sol et ses propriétés. C’est l’objet d’une méthode développée en agronomie et qu’on peut adapter au milieu forestier : le profil cultural. Voyons de quoi il s’agit.

ano.nymous@ccsd.cnrs.fr.invalid (Florian Vast) 14 Oct 2020

https://hal.science/hal-02963149v1

[hal-03037487] Cultivation profile: a visual evaluation method of soil structure adapted to the analysis of the impacts of mechanical site preparation in forest plantations

Mechanical site preparation (MSP) is widely used in forestry to improve plantation success. Although it is known to alter soil properties, its direct effects on soil structure have rarely been described. The cultivation profile is a visual soil evaluation (VSE) method developed in agricultural research to analyse the impacts of cultivation practices on soil structure. The objective of the study was to adapt the method to forest plantations in order to analyse the effects of MSP on soil quality. Cultivation profiles were performed in six experimental plantation sites located in Northern France. The method made it possible to compare the impacts on soil structure of three MSP methods. It provided a schematic representation of the soil structural quality and a quantitative estimation of the volume of soil favourable to seedling root growth. It also highlighted unexpected negative effects of some MSP methods on soil structure, such as the creation of small cavities, the presence of compacted soil volumes due to wheel tracks or smeared soil volumes due to tool pass, and the pseudogleisation of soil zones due to changes in water circulation in the soil. The relevance and limitations of VSE methods in the context of forest plantation as well as the expected future development of the methods are discussed.

ano.nymous@ccsd.cnrs.fr.invalid (Catherine Collet) 03 Dec 2020

https://hal.inrae.fr/hal-03037487v1

[hal-02544340] Comment l'Office national des forêts anticipe les effets du changement climatique ?

En charge de la gestion de onze millions d'hectares de forêts publiques, dont 4,6 millions d’hectares en métropole, l’Office national des forêts (ONF) est un acteur majeur de la filière forêt-bois en France. Depuis 2005, le changement climatique s’est imposé à l’ONF comme une priorité de recherche et de développement. Pour adapter les forêts au climat de demain et préserver les stocks de carbone, son département « Recherche développement et innovation » s’est rapproché des acteurs de la recherche en France. Dans cet article, les auteurs font le point des travaux et actions menés au cours des quatorze dernières années et de leur appropriation par les services de gestion.

ano.nymous@ccsd.cnrs.fr.invalid (Myriam Legay) 21 Apr 2020

https://hal.science/hal-02544340v1

[hal-03179773] Temporal trends in tree defoliation and response to multiple biotic and abiotic stresses

The vitality of forests depends on multiple biotic and abiotic stresses that can act in an interactive way. Tree defoliation levels are therefore subject to long-term changes and shorter-term hazards that need to be monitored in the context of ongoing climate change. In this study, we analysed the combined effects of drought, insect attack and tree nutritional status on the level of defoliation in three major hardwood species in Europe: European beech (Fagus sylvatica), sessile oak (Quercus petraea) and pedunculate oak (Quercus robur). The forest condition data set was collected in the long-term intensive monitoring network in France (RENECOFOR). The average level of defoliation observed was 20% but varied considerably between plots and trees. From 1997 to 2015, beech defoliation worsened by 10% while oak defoliation stabilized over time. For the three tree species, crown defoliation was generally higher in the event of insect attack (increased by 2.6% to 7.5% depending on the tree species) and under drought (increased by 5.9%), while the effect of the tree nutritional statue was less consistent (from - 5.6% to + 10%) these factors acting synergistically. This study highlights the fact that the different stresses a tree species undergoes act in a complex and interactive way, with species-specific responses. In a context of increasing abiotic and biotic stresses, their combined analysis appears to be a necessity at a time when forest owners need to adapt their management to cope with climate change, particularly through the choice of tree species to be favoured in the future.

ano.nymous@ccsd.cnrs.fr.invalid (Maude Toïgo) 25 Aug 2022

https://hal.inrae.fr/hal-03179773v1

[hal-03051411] Energy, water and carbon exchanges in managed forest ecosystems: description, sensitivity analysis and evaluation of the INRAE GO+ model, version 3.0

The mechanistic model GO+ describes the functioning and growth of managed forests based upon biophysical and biogeochemical processes. The biophysical and biogeochemical processes included are modelled using standard formulations of radiative transfer, convective heat exchange, evapotranspiration, photosynthesis, respiration, plant phenology, growth and mortality, biomass nutrient content, and soil carbon dynamics. The forest ecosystem is modelled as three layers, namely the tree overstorey, understorey and soil. The vegetation layers include stems, branches and foliage and are partitioned dynamically between sunlit and shaded fractions. The soil carbon submodel is an adaption of the Roth-C model to simulate the impact of forest operations. The model runs at an hourly time step. It represents a forest stand covering typically 1 ha and can be straightforwardly upscaled across gridded data at regional, country or continental levels. GO+ accounts for both the immediate and long-term impacts of forest operations on energy, water and carbon exchanges within the soil–vegetation–atmosphere continuum. It includes exhaustive and versatile descriptions of management operations (soil preparation, regeneration, vegetation control, selective thinning, clear-cutting, coppicing, etc.), thus permitting the effects of a wide variety of forest management strategies to be estimated: from close to nature to intensive. This paper examines the sensitivity of the model to its main parameters and estimates how errors in parameter values are propagated into the predicted values of its main output variables.The sensitivity analysis demonstrates an interaction between the sensitivity of variables, with the climate and soil hydraulic properties being dominant under dry conditions but the leaf biochemical properties being most influential with wet soil. The sensitivity profile of the model changes from short to long timescales due to the cumulative effects of the fluxes of carbon, energy and water on the stand growth and canopy structure. Apart from a few specific cases, the model simulations are close to the values of the observations of atmospheric exchanges, tree growth, and soil carbon and water stock changes monitored over Douglas fir, European beech and pine forests of different ages. We also illustrate the capacity of the GO+ model to simulate the provision of key ecosystem services, such as the long-term storage of carbon in biomass and soil under various management and climate scenarios.

ano.nymous@ccsd.cnrs.fr.invalid (Virginie Moreaux) 10 Dec 2020

https://hal.inrae.fr/hal-03051411v1

[hal-02541780] Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling

The impact of atmospheric reactive nitrogen (Nr) deposition on carbon (C) sequestration in soils and biomass of unfertilized, natural, semi-natural and forest ecosystems has been much debated. Many previous results of this dC∕dN response were based on changes in carbon stocks from periodical soil and ecosystem inventories, associated with estimates of Nr deposition obtained from large-scale chemical transport models. This study and a companion paper (Flechard et al., 2020) strive to reduce uncertainties of N effects on C sequestration by linking multi-annual gross and net ecosystem productivity estimates from 40 eddy covariance flux towers across Europe to local measurement-based estimates of dry and wet Nr deposition from a dedicated collocated monitoring network. To identify possible ecological drivers and processes affecting the interplay between C and Nr inputs and losses, these data were also combined with in situ flux measurements of NO, N2O and CH4 fluxes; soil NO−3 leaching sampling; and results of soil incubation experiments for N and greenhouse gas (GHG) emissions, as well as surveys of available data from online databases and from the literature, together with forest ecosystem (BASFOR) modelling.

ano.nymous@ccsd.cnrs.fr.invalid (Chris Flechard) 15 Jul 2020

https://hal.inrae.fr/hal-02541780v1

[hal-03005990] Tree mode of death and mortality risk factors across Amazon forests

The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing &gt; 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality.

ano.nymous@ccsd.cnrs.fr.invalid (Adriane Esquivel-Muelbert) 17 Nov 2020

https://hal.science/hal-03005990v1

[hal-02948828] Microgeographic local adaptation and ecotype distributions: The role of selective processes on early life‐history traits in sympatric, ecologically divergent Symphonia populations

Trees are characterized by the large number of seeds they produce. Although most of those seeds will never germinate, plenty will. Of those which germinate, many die young, and eventually, only a minute fraction will grow to adult stage and reproduce. Is this just a random process? Do variations in germination and survival at very young stages rely on variations in adaptations to microgeographic heterogeneity? and do these processes matter at all in determining tree species distribution and abundance?We have studied these questions with the Neotropical Symphonia tree species. In the Guiana shield, Symphonia are represented by at least two sympatric taxa or ecotypes, Symphonia globulifera found almost exclusively in bottomlands, and a yet undescribed more generalist taxon/ecotype, Symphonia sp1. A reciprocal transplantation experiment (510 seeds, 16 conditions) was set up and followed over the course of 6 years to evaluate the survival and performance of individuals from different ecotypes and provenances.Germination, survival, growth, and herbivory showed signs of local adaptation, with some combinations of ecotypes and provenances growing faster and surviving better in their own habitat or provenance region. S. globulifera was strongly penalized when planted outside its home habitat but showed the fastest growth rates when planted in its home habitat, suggesting it is a specialist of a high‐risk high‐gain strategy. Conversely, S. sp1 behaved as a generalist, performing well in a variety of environments.The differential performance of seeds and seedlings in the different habitats matches the known distribution of both ecotypes, indicating that environmental filtering at the very early stages can be a key determinant of tree species distributions, even at the microgeographic level and among very closely related taxa. Furthermore, such differential performance also contributes to explain, in part, the maintenance of the different Symphonia ecotypes living in intimate sympatry despite occasional gene flow.

ano.nymous@ccsd.cnrs.fr.invalid (Niklas Tysklind) 30 Sep 2020

https://hal.science/hal-02948828v1

[hal-02995533] Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites

We apply and compare three widely applicable methods for estimating ecosystem transpiration (T) from eddy covariance (EC) data across 251 FLUXNET sites globally. All three methods are based on the coupled water and carbon relationship, but they differ in assumptions and parameterizations. Intercomparison of the three daily T estimates shows high correlation among methods (R between .89 and .94), but a spread in magnitudes of T/ET (evapotranspiration) from 45% to 77%. When compared at six sites with concurrent EC and sap flow measurements, all three EC‐based T estimates show higher correlation to sap flow‐based T than EC‐based ET. The partitioning methods show expected tendencies of T/ET increasing with dryness (vapor pressure deficit and days since rain) and with leaf area index (LAI). Analysis of 140 sites with high‐quality estimates for at least two continuous years shows that T/ET variability was 1.6 times higher across sites than across years. Spatial variability of T/ET was primarily driven by vegetation and soil characteristics (e.g., crop or grass designation, minimum annual LAI, soil coarse fragment volume) rather than climatic variables such as mean/standard deviation of temperature or precipitation. Overall, T and T/ET patterns are plausible and qualitatively consistent among the different water flux partitioning methods implying a significant advance made for estimating and understanding T globally, while the magnitudes remain uncertain. Our results represent the first extensive EC data‐based estimates of ecosystem T permitting a data‐driven perspective on the role of plants’ water use for global water and carbon cycling in a changing climate.

ano.nymous@ccsd.cnrs.fr.invalid (Jacob Nelson) 07 Jun 2022

https://hal.univ-lorraine.fr/hal-02995533v1

[hal-02959147] Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads

Studying the response to drought stress of keystone epiphytes such as tank bromeliads is essential to better understand their resistance capacity to future climate change. The objective was to test whether there is any variation in the carbon, water and nutrient status among different leaf ontogenetic stages in a bromeliad rosette subjected to a gradient of drought stress. We used a semi-controlled experiment consisting in a gradient of water shortage in Aechmea aquilega and Lutheria splendens. For each bromeliad and drought treatment, three leaves were collected based on their position in the rosette and several functional traits related to water and nutrient status, and carbon metabolism were measured. We found that water status traits (relative water content, leaf succulence, osmotic and midday water potentials) and carbon metabolism traits (carbon assimilation, maximum quantum yield of photosystem II, chlorophyll and starch contents) decreased with increasing drought stress, while leaf soluble sugars and carbon, nitrogen and phosphorus contents remained unchanged. The different leaf ontogenetic stages showed only marginal variations when subjected to a gradient of drought. Resources were not reallocated between different leaf ontogenetic stages but we found a reallocation of soluble sugars from leaf starch reserves to the root system. Both species were capable of metabolic and physiological adjustments in response to drought. Overall, this study advances our understanding of the resistance of bromeliads faced with increasing drought stress and paves the way for in-depth reflection on their strategies to cope with water shortage.

ano.nymous@ccsd.cnrs.fr.invalid (Mia Svensk) 06 Oct 2020

https://hal.science/hal-02959147v1

[hal-02948755] Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests

Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. However, studies addressing the effects of forest degradation on carbon, water, and energy cycles are scarce. Here, we integrate field observations and high‐resolution remote sensing from airborne lidar to provide realistic initial conditions to the Ecosystem Demography Model (ED‐2.2) and investigate how disturbances from forest degradation affect gross primary production (GPP), evapotranspiration (ET), and sensible heat flux (H). We used forest structural information retrieved from airborne lidar samples (13,500 ha) and calibrated with 817 inventory plots (0.25 ha) across precipitation and degradation gradients in the eastern Amazon as initial conditions to ED‐2.2 model. Our results show that the magnitude and seasonality of fluxes were modulated by changes in forest structure caused by degradation. During the dry season and under typical conditions, severely degraded forests (biomass loss ≥66%) experienced water stress with declines in ET (up to 34%) and GPP (up to 35%) and increases of H (up to 43%) and daily mean ground temperatures (up to 6.5°C) relative to intact forests. In contrast, the relative impact of forest degradation on energy, water, and carbon cycles markedly diminishes under extreme, multiyear droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are driven by not only climate and deforestation but also the past disturbance and changes of forest structure from degradation, suggesting a much broader influence of human land use activities on the tropical ecosystems.

ano.nymous@ccsd.cnrs.fr.invalid (Marcos Longo) 13 Oct 2020

https://hal.inrae.fr/hal-02948755v1

[hal-02948747] Contrasting patterns of tree species mixture effects on wood δ13C along an environmental gradient

Establishing mixed-species stands is frequently proposed as a strategy to adapt forests to the increasing risk of water scarcity, yet contrasted results have been reported regarding mixing effects on tree drought exposure. To investigate the drivers behind the spatial and temporal variation in water-related mixing effects, we analysed the delta C-13 variation in 22-year tree ring chronologies for beech and pine trees sampled from 17 pure and mixed pine-beech stands across a large gradient of environmental conditions throughout Europe. In the pure stands, average delta C-13 values were lower for beech (-27.9 parts per thousand to -22.2 parts per thousand) than for pine (-26.0 parts per thousand to -21.1 parts per thousand), irrespective of site conditions. Decreasing SPEI values (calculated over June to September) were associated with an increase in delta C-13 for both species, but their effect was influenced by stand basal area for pine and site water availability for beech. Mixing did not change the temporal constancy of delta C-13 nor the tree reaction to a drought event, for any of the species. While the mixing effect (Delta delta C-13 = delta C-13 pure stands - delta C-13 mixed stands) was on average positive for beech and non-significant for pine across the whole gradient, this effect strongly differed between sites. For both species, mixing was not significant at extremely dry sites and positive at dry sites; on moderately wet sites, mixing was positive for beech and negative for pine; at sites with permanent water supply, no general patterns emerge for any of the species. The pattern of mixing effect along the gradient of water availability was not linear but showed threshold points, highlighting the need to investigate such relation for other combinations of tree species.

ano.nymous@ccsd.cnrs.fr.invalid (G. de Streel) 25 Oct 2023

https://hal.inrae.fr/hal-02948747v1

[hal-02927318] How does contemporary selection shape oak phenotypes?

Most existing forests are subjected to natural and human-mediated selection pressures, which have increased due to climate change and the increasing needs of human societies for wood, fibre and fuel resources. It remains largely unknown how these pressures trigger evolutionary changes. We address this issue here for temperate European oaks (Quercus petraeaandQ. robur), which grow in mixed stands, under even-aged management regimes. We screened numerous functional traits for univariate selection gradients and for expected and observed genetic changes over two successive generations. In both species, growth, leaf morphology and physiology, and defence-related traits displayed significant selection gradients and predicted shifts, whereas phenology, water metabolism, structure and resilience-related traits did not. However, the direction of the selection response and the potential for adaptive evolution differed between the two species.Quercus petraeahad a much larger phenotypic and genetic variance of fitness thanQ. robur. This difference raises concerns about the adaptive response ofQ. roburto contemporary selection pressures. Our investigations suggest thatQ. roburwill probably decline steadily, particularly in mixed stands withQ. petraea, consistent with the contrasting demographic dynamics of the two species.

ano.nymous@ccsd.cnrs.fr.invalid (Hermine Alexandre) 01 Sep 2020

https://hal.inrae.fr/hal-02927318v1

[hal-02870299] Which oak provenances for the 22nd century in Western Europe? Dendroclimatology in common gardens

The current distribution area of the two sympatric oaks Quercus petraea and Q. robur covers most of temperate Western Europe. Depending on their geographic location, populations of these trees are exposed to different climate constraints, to which they are adapted. Comparing the performances of trees from contrasting populations provides the insight into their expected resilience to future climate change required for forest management. In this study, the descendants of 24 Q. petraea and two Q. robur provenances selected from sites throughout Europe were grown for 20 years in three common gardens with contrasting climates. The 2420 sampled trees allowed the assessments of the relationship between radial growth and climate. An analysis of 15-year chronologies of ring widths, with different combinations of climate variables, revealed different response patterns between provenances and between common gardens. As expected, provenances originating from sites with wet summers displayed the strongest responses to summer drought, particularly in the driest common garden. All provenances displayed positive significant relationships between the temperature of the previous winter and radial growth when grown in the common garden experiencing the mildest winter temperatures. Only eastern provenances from continental cold climates also clearly expressed this limitation of growth by cold winter temperatures in the other two common gardens. However, ecological distance, calculated on the basis of differences in climate between the site of origin and the common garden, was not clearly related to the radial growth responses of the provenances. This suggests that the gradient of genetic variability among the selected provenances was not strictly structured according to climate gradients. Based on these results, we provide guidelines for forest managers for the assisted migration of Quercus petraea and Q. robur provenances.

ano.nymous@ccsd.cnrs.fr.invalid (Didier Bert) 08 Jan 2021

https://hal.science/hal-02870299v1

[hal-03207504] Altered energy partitioning across terrestrial ecosystems in the European drought year 2018

Drought and heat events, such as the 2018 European drought, interact with the exchange of energy between the land surface and the atmosphere, potentially affecting albedo, sensible and latent heat fluxes, as well as CO 2 exchange. Each of these quantities may aggravate or mitigate the drought, heat, their side effects on productivity, water scarcity and global warming. We used measurements of 56 eddy covariance sites across Europe to examine the response of fluxes to extreme drought prevailing most of the year 2018 and how the response differed across various ecosystem types (forests, grasslands, croplands and peatlands). Each component of the surface radiation and energy balance observed in 2018 was compared to available data per site during a reference period 2004–2017. Based on anomalies in precipitation and reference evapotranspiration, we classified 46 sites as drought affected. These received on average 9% more solar radiation and released 32% more sensible heat to the atmosphere compared to the mean of the reference period. In general, drought decreased net CO 2 uptake by 17.8%, but did not significantly change net evapotranspiration. The response of these fluxes differed characteristically between ecosystems; in particular, the general increase in the evaporative index was strongest in peatlands and weakest in croplands. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

ano.nymous@ccsd.cnrs.fr.invalid (Alexander Graf) 25 Apr 2021

https://hal.inrae.fr/hal-03207504v1

[hal-02652095] Decreasing stand density favors resistance, resilience, and recovery of Quercus petraea trees to a severe drought, particularly on dry sites

Key message Decreasing stand density increases resistance, resilience, and recovery ofQuercus petraeatrees to severe drought (2003), particularly on dry sites, and the effect was independent of tree social status. Context Controlling competition is an advocated strategy to modulate the response of trees to predicted changes in climate. Aims We investigated the effects of stand density (low, medium, high; relative density index 0.20, 0.53, 1.04), social status (dominant, codominant, suppressed), and water balance (dry, mesic, wet; summer water balance - 182, - 126, - 96 mm) on the climate-growth relationships (1997-2012) and resistance (Rt), resilience (Rs), and recovery (Rc) following the 2003 drought. Methods Basal area increments were collected by coring (269 trees) in young stands (28 +/- 7.5 years in 2012) of sessile oak (Quercus petraea) in a French permanent network of silvicultural plots. Results We showed that the climate-growth relationships depend on average site-level water balance with trees highly dependent on spring and summer droughts on dry and mesic sites and not at all on wet sites. Neither stand density nor social status modulated mean response to climate. Decreasing stand density increased Rt, Rs, and Rc particularly on dry sites. The effect was independent of tree social position within the stand. Conclusion Reducing stand density mitigates more the effect of extreme drought events on drier sites than on wet sites.

ano.nymous@ccsd.cnrs.fr.invalid (Anna Schmitt) 14 Aug 2020

https://hal.inrae.fr/hal-02652095v1

[hal-03029648] Diversity and potentiality of multi-criteria decision analysis methods for agri-food research

AbstractThere is a growing demand for moving towards sustainable agri-food systems which per nature covers a complex network of activities and domains; such systems will benefit from multi-criteria decision analysis (MCDA) methods. Although some reviews on MCDA in agri-food research have been published, none of them covered the whole value chain. In this article, a corpus of 954 articles published by INRA scientists from 2007 to 2017 was used to study the diversity and potentiality of MCDA techniques. For the first time, experts from more than 10 agri-food domains worked altogether to annotate the articles, carry out a multivariate analysis, and finally interpret the statistical results to identify the specificities of certain domains and the complementarities between domains and to suggest avenues for future agri-food research. One-third of the studies were based only on a list of indicators, even when their purpose was to choose, sort, or rank options. Regardless of the scientific discipline in the agri-food sector, MCDA studies rarely considered temporal dynamics, spatial scale changes, or stakeholder contributions. As the agri-food system becomes increasingly sustainable in the near future, the use of MCDA methods will accelerate. To become more effective, they will have to include ecosystem services, even outside the scope of ecological studies. Similarly, MCDA studies will need to include participatory science to involve stakeholders (i.e., public authorities, governmental agencies) and end-users (i.e., farmers, producers, industrials, consumers) in the construction of the multi-criteria evaluation but also in the resulting decisions.

ano.nymous@ccsd.cnrs.fr.invalid (Geneviève Gésan-Guiziou) 22 Nov 2021

https://hal.inrae.fr/hal-03029648v1

[hal-03040730] In situ estimation of genetic variation of functional and ecological traits in Quercus petraea and Q. robur

Predicting the evolutionary potential of natural tree populations requires the estimation of heritability and genetic correlations among traits on which selection acts, as differences in evolutionary success between species may rely on differences for these genetic parameters. In situ estimates are expected to be more accurate than measures done under controlled conditions which do not reflect the natural environmental variance. The aim of the current study was to estimate three genetic parameters (i.e., heritability, evolvability, and genetic correlations) in a natural mixed oak stand composed of Quercus petraea and Quercus robur about 100 years old, for 58 traits of ecological, and functional relevance (growth, reproduction, phenology, physiology, resilience, structure, morphology, and defense). First, we estimated genetic parameters directly in situ using realized genomic relatedness of adult trees and parentage relationships over two generations to estimate the traits' additive variance. Secondly, we benefited from existing ex situ experiments (progeny tests and conservation collection) installed with the same populations, thus allowing comparisons of in situ heritability estimates with more traditional methods. Heritability and evolvability estimates obtained with different methods varied substantially and showed large confidence intervals; however, we found that in situ were less precise than ex situ estimates, and assessments over two generations (with deeper relatedness) improved estimates of heritability while large sampling sizes are needed for accurate estimations. At the biological level, heritability values varied moderately across different ecological and functional categories of traits, and genetic correlations among traits were conserved over the two species. We identified limits for using realized genomic relatedness in natural stands to estimate the genetic variance, given the overall low variance of genetic relatedness and the rather low sampling sizes of currently used long-term genetic plots in forestry. These limits can be overcome if larger sample sizes are considered, or if the approach is extended over the next generation.

ano.nymous@ccsd.cnrs.fr.invalid (Hermine Alexandre) 16 Sep 2024

https://hal.inrae.fr/hal-03040730v1

[hal-02610246] Species mixing reduces drought susceptibility of Scots pine (Pinus sylvestris L.) and oak (Quercus robur L., Quercus petraea (Matt.) Liebl.) - Site water supply and fertility modify the mixing effect

Tree species mixing has been widely promoted as a promising silvicultural tool for reducing drought stress. However, so far only a limited number of species combinations have been studied in detail, revealing inconsistent results. In this study, we analysed the effect of mixing Scots pine and oak (pedunculate oak and sessile oak) trees on their drought response along a comprehensive ecological gradient across Europe. The objective was to improve our knowledge of general drought response patterns of two fundamental European tree species in mixed versus monospecific stands. We focused on three null hypotheses: (HI) tree drought response does not differ between Scots pine and oak, (HII) tree drought response of Scots pine and oak is not affected by stand composition (mixture versus monoculture) and (HIII) tree drought response of Scots pine and oak in mixtures and monocultures is not modified by tree size or site conditions. To test the hypotheses, we analysed increment cores of Scots pine and oak, sampled in mixed and monospecific stands, covering a wide range of site conditions. We investigated resistance (the ability to maintain growth levels during drought), recovery (the ability to restore a level of growth after drought) and resilience (the capacity to recover to pre-drought growth levels), involving sitespecific drought events that occurred between 1976 and 2015. In monocultures, oak showed a higher resistance and resilience than Scots pine, while recovery was lower. Scots pine in mixed stands exhibited a higher resistance, but also a lower recovery compared with Scots pine in monocultures. Mixing increased the resistance and resilience of oak. Ecological factors such as tree size, site water supply and site fertility were found to have significant effects on the drought response. In the case of Scots pine, resistance was increased by tree size, while recovery was lowered. Resistance of oak increased with site water supply. The observed mixing effect on the tree drought response of Scots pine and oak was in some cases modified by the site conditions studied. Positive mixing effects in terms of resistance and resilience of oak increased with site water supply, while the opposite was found regarding recovery. In contrast, site fertility lessened the positive mixing effect on the resistance of Scots pine. We hypothesise that the observed positive mixing effects under drought mainly result from waterand/or light-related species interactions that improve resource availability and uptake according to temporal and spatial variations in environmental conditions.

ano.nymous@ccsd.cnrs.fr.invalid (M. Steckel) 16 May 2020

https://hal.inrae.fr/hal-02610246v1

[hal-02610238] Stand growth and structure of mixed-species and monospecific stands of Scots pine (Pinus sylvestris L.) and oak (Q. robur L., Quercus petraea (Matt.) Liebl.) analysed along a productivity gradient through Europe

Past failures of monocultures, caused by wind-throw or insect damages, and ongoing climate change currently strongly stimulate research into mixed-species stands. So far, the focus has mainly been on combinations of species with obvious complementary functional traits. However, for any generalization, a broad overview of the mixing reactions of functionally different tree species in different mixing proportions, patterns and under different site conditions is needed, including assemblages of species with rather similar demands on resources such as light. Here, we studied the growth of Scots pine and oak in mixed versus monospecific stands on 36 triplets located along a productivity gradient across Europe, reaching from Sweden to Spain and from France to Georgia. The set-up represents a wide variation in precipitation (456-1250 mm year-1), mean annual temperature (6.7-11.5 °C) and drought index by de Martonne (21-63 mm °C-1). Stand inventories and increment cores of trees stemming from 40- to 132-year-old, fully stocked stands on 0.04-0.94-ha-sized plots provided insight into how species mixing modifies stand growth and structure compared with neighbouring monospecific stands. On average, the standing stem volume was 436 and 360 m3 ha-1 in the monocultures of Scots pine and oak, respectively, and 418 m3 ha-1 in the mixed stands. The corresponding periodical annual volume increment amounted to 10.5 and 9.1 m3 ha-1 year-1 in the monocultures and 10.5 m3 ha-1 year-1 in the mixed stands. Scots pine showed a 10% larger quadratic mean diameter (p is smaller than 0.05), a 7% larger dominant diameter (p is smaller than 0.01) and a 9% higher growth of basal area and volume in mixed stands compared with neighbouring monocultures. For Scots pine, the productivity advantages of growing in mixture increased with site index (p is smaller than 0.01) and water supply (p is smaller than 0.01), while for oak they decreased with site index (p is smaller than 0.01). In total, the superior productivity of mixed stands compared to monocultures increased with water supply (p is smaller than 0.10). Based on 7843 measured crowns, we found that in mixture both species, but especially oak, had significantly wider crowns (p is smaller than 0.001) than in monocultures. On average, we found relatively small effects of species mixing on stand growth and structure. Scots pine benefiting on rich, and oak on poor sites, allows for a mixture that is productive and most likely climate resistant all along a wide ecological gradient. We discuss the potential of this mixture in view of climate change.

ano.nymous@ccsd.cnrs.fr.invalid (Hans Pretzsch) 16 May 2020

https://hal.inrae.fr/hal-02610238v1

[hal-03014264] Snow cover duration trends observed at sites and predicted by multiple models

Abstract. Thirty-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.

ano.nymous@ccsd.cnrs.fr.invalid (Richard Essery) 05 Jan 2021

https://hal.science/hal-03014264v2

[hal-03040751] New developments in understanding plant water transport under drought stress

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ano.nymous@ccsd.cnrs.fr.invalid (Amanda A Cardoso) 04 Dec 2020

https://hal.inrae.fr/hal-03040751v1

[hal-03365826] Assessing the dominant height of oriental beech (Fagus orientalis L.) in relation to edaphic and physiographic variables in the Hyrcanian Forests of Iran

Description of the subject. This study evaluates the application of Boosted Regression Trees (BRT) for predicting beech dominant height in the Hyrcanian forests of Iran, inscribed as a UNESCO’s World Heritage due to its remarkable biodiversity. Objectives. It is widely accepted that tree growth can be influenced by a wide variety of factors such as climate, topography, soil conditions and competition for resources. The early dominant height of trees modelling studies used the multiple linear regression. The development of more advanced non-parametric and machine learning methods provided opportunities to overcome the nonlinear relationships in forest ecosystems. Method. In this study, boosted regression trees was evaluated to model the dominant height of Fagus orientalis as the most important tree species in the Hyrcanian forest, Iran. Dominant height was related to soil and topographical variables, which are available for 190 sample plots covering all importance environmental gradients in the research area. Results. The results indicated BRT were found to outperform for modelling beech dominant height. This technique showed that phosphorus, percentage nitrogen, magnesium and percentage sand were among the most important variables. Conclusions. This study demonstrates the ability of BRT to accurately model the dominant height of oriental beech in relation to environmental predictors, and encourages its use in forest ecology.

ano.nymous@ccsd.cnrs.fr.invalid (Seyed Jalil Alavi) 05 Oct 2021

https://hal.inrae.fr/hal-03365826v1

[hal-02978675] Perspectives d'émergence d'une filière forêt-chimie des extractibles Points de vue des acteurs du Nord-Est de la France et du Sud-Ouest de l'Allemagne

La biomasse forestière peut être une source de molécules d’intérêt dans le but de substituer ou de compléter les molécules pétro-sourcées. Par conséquent, une valorisation innovante des extractibles du bois semble être une opportunité économique, sociale et environnementale. L’objectif de notre étude est de mieux cerner les perspectives d’émergence d’une nouvelle valorisation chimique des connexes bois pour la région Grand Est, à partir des avis et ressentis des acteurs de la filière forêt-bois et de la valorisation chimique de cette région ainsi que de territoires voisins. Nos résultats se portent sur trois axes : les stratégies de valorisation des connexes des entreprises de la filière forêt-bois, les perceptions des acteurs sur l’émergence d’une filière forêt-chimie, et les perspectives de mise en place d’une telle filière à moyen terme. Nous conviendrons tout de même que les résultats doivent être approfondis dans le cadre de perspectives de recherche pour préciser les conditions de la mise en œuvre de cette filière.

ano.nymous@ccsd.cnrs.fr.invalid (Frédéric Bonin) 26 Oct 2020

https://agroparistech.hal.science/hal-02978675v1

[hal-03006193] The pantropical response of soil moisture to El Niño

The 2015-2016 El Nino event ranks as one of the most severe on record in terms of the magnitude and extent of sea surface temperature (SST) anomalies generated in the tropical Pacific Ocean. Corresponding global impacts on the climate were expected to rival, or even surpass, those of the 1997-1998 severe El Nino event, which had SST anomalies that were similar in size. However, the 2015-2016 event failed to meet expectations for hydrologic change in many areas, including those expected to receive well above normal precipitation. To better understand how climate anomalies during an El Nino event impact soil moisture, we investigate changes in soil moisture in the humid tropics (between +/- 25 degrees) during the three most recent super El Nino events of 1982-1983,1997-1998 and 2015-2016, using data from the Global Land Data Assimilation System (GLDAS). First, we use in situ soil moisture observations obtained from 16 sites across five continents to validate and bias-correct estimates from GLDAS (r(2) = 0.54). Next, we apply a k-means cluster analysis to the soil moisture estimates during the El Nino mature phase, resulting in four groups of clustered data. The strongest and most consistent decreases in soil moisture occur in the Amazon basin and maritime southeastern Asia, while the most consistent increases occur over eastern Africa. In addition, we compare changes in soil moisture to both precipitation and evapotranspiration, which showed a lack of agreement in the direction of change between these variables and soil moisture most prominently in the southern Amazon basin, the Sahel and mainland southeastern Asia. Our results can be used to improve estimates of spatiotemporal differences in El Nino impacts on soil moisture in tropical hydrology and ecosystem models at multiple scales.

ano.nymous@ccsd.cnrs.fr.invalid (Kurt C Solander) 15 Nov 2020

https://hal.inrae.fr/hal-03006193v1

[hal-02527995] Distribution of soil properties along forest-grassland interfaces: Influence of permanent environmental factors or land-use after-effects?

Soil properties vary spatially according to land use; both because land users have selected specific soil properties for specific land uses, and land uses modify the soil properties. However, permanent environment factors and land-use effects are unlikely to display the exact same spatial patterns. Study of the spatial and historical patterns of distribution of soil properties could help to separate between these two causes. In this aim, we studied 22 forest-grassland interfaces with controlled historical configurations in northeast France. In each land use (forest and grassland), three distances to the edge (edge, periphery and core) and two land-use histories (ancient and recent) were studied.Along forest-grassland interfaces, forests were usually located slightly upslope of grasslands, and mainly because this non-random topographic position the topsoil texture was significantly more silty in forests, and clayey in grasslands. After statistically controlling for the effects of topography and soil texture, we observed two main gradients of variation in soil properties according to the distance-to-edge (acidity in forest and nutrient content in grassland). In forest, pH and Ca dropped from the edges to the peripheries (15 m distance), while in grassland, C, N, P and Na sharply increased from the edges to the cores (25 m distance). These results demonstrate, through the edge effect, the strong influence of the land use on a part of soil properties. Furthermore, less than two centuries after grassland afforestation or deforestation, we observed that soil properties in recent forests and recent grasslands were respectively closer to their current land use than to their former land use. These results demonstrate a rapid change in soil properties after land-use change. However, recent forests and recent grasslands kept a legacy of soil texture from their former land use, respectively. Recent grasslands also kept a lower soil density, N and Na content compared to ancient grasslands.Hence, this study of forest-grassland interfaces show strong and short-scale relationships between land use and soil properties and suggest that they express both original choices of land users for specific soil properties and land-use after-effects. The non-random topographic position of the forest-grassland interfaces indicates a conscious choice of this positioning by the land users, for agronomic reasons. Beyond that, land use, through vegetation composition and management practices, also has a strong impact on soil properties. The fact that land-use changes affect most soil properties after only a few decades confirms the existence of land-use effects over time.

ano.nymous@ccsd.cnrs.fr.invalid (Maxime Burst) 21 Dec 2021

https://hal.inrae.fr/hal-02527995v1

[hal-02949790] A standard protocol for reporting species distribution models

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ano.nymous@ccsd.cnrs.fr.invalid (Damaris Zurell) 12 Nov 2020

https://hal.inrae.fr/hal-02949790v1

[hal-03206201] Valuation de la ressource territoriale et formes de circularité : la labellisation dans la filière forêt-bois française (Alpes, Jura, Vosges)

La multiplication des labels territoriaux dans le secteur forêt-bois semble s’inscrire en réponse aux pressions croissantes et combinées d’une économie mondialisée et aux exigences sociales et environnementales, conditions d’un développement durable. Partant des développements récents en économie territoriale, nous élargissons la question de la spécification de la ressource bois par l’analyse des modalités de sa valuation. À travers l’étude des démarches de labellisation dans les Alpes, les Vosges et le Jura, nous analysons les portefeuilles de valeur construits et mobilisés par le collectif et nous mettons en évidence les différentes formes de circularité qui y sont liées. Nous montrons que les labels bois se construisent de plus en plus surdes valeurs de territorialité, à travers l’activation de différentes formes de proximité. Encore très récentes, ces démarches s’instiguent en « contre-normes » et remettent en cause le modèle productif dominant sur la base d’alternatives territorialisées.

ano.nymous@ccsd.cnrs.fr.invalid (Jonathan Lenglet) 23 Apr 2021

https://agroparistech.hal.science/hal-03206201v1

[hal-02534416] Selecting for water use efficiency, wood chemical traits and biomass with genomic selection in a Eucalyptus breeding program

The selection of ideotypes combining high biomass production, high water use efficiency (WUE) and adequate wood properties is a major challenge in improving forest trees for industrial plantations. This issue was addressed in a field experiment evaluating 1130 clones of Eucalyptus urophylla * Eucalyptus grandis. Genomic selection using 3303 SNPs and the GBLUP model was carried out at age 55 months to select genitors and clones for stem volume (V55), WUE (using stable carbon isotope composition in stemwood, δ13C as a proxy, transformed into intrinsic WUE, Wi), as well as lignin (KL) and holocellulose (HCEL) contents. The variance components were mainly additive for δ13C(Wi), KL and HCEL, while they were highly non-additive for V55 (the ratio of dominance to additive variance was 130%). The narrow sense heritability was higher for Wi (h2 = 0.704) than for volume and wood traits (<0.5), showing that this trait was under strong genetic control. Additive and total genetic correlations among traits were low (between −0.260 and 0.260) as were the correlations due to environmental effects (between −0.267 and 0.344), which suggests a rather independence among traits. The equal emphasis and the desired gain index selection methods were used to assess economic weights and to estimate the expected additive and total genetic gains. Different breeding objectives were defined with percentages weighting the economic coefficients or the desired gain for the equal emphasis or desired gain method, respectively. When the breeding objective gave emphasis to volume production using the percentages of 70%, 10%, 10%, and 10% for V55, HCEL, KL and Wi, respectively, positive gains were observed in both methods, but the correlation between index rankings were 0.686 and 0.635 for breeding and clonal selection, respectively. With a more balanced breeding objective using percentages such as 25%, 25%, 25%, 25% for V55, HCEL, KL and Wi, respectively, both index methods gave close positive gains and similar rankings, the correlation between index rankings ranging from 0.941 to 0.982 for parent selection and from 0.883 to 0.903 for clone selection. With more contrasted percentages between V55 and Wi, such as (80%, 10%, 10%, 0%) or (90%, 10%, 10%, −10%), the gain increased for V55 and was close to the maximum and decreased markedly for Wi. This study explores the magnitude of economic coefficients for index selection and shows that positive genetic gains can be achieved by associating biomass, a proxy of WUE and wood chemical traits. It provides encouraging results for selecting Eucalyptus varieties adapted to dry zones while maintaining good performances regarding other economic traits.

ano.nymous@ccsd.cnrs.fr.invalid (Jean-Marc Bouvet) 22 Aug 2022

https://hal.inrae.fr/hal-02534416v1

[hal-03317972] Ancient forest statistics provide centennial perspective over the status and dynamics of forest area in France

Context: The history of European forest dynamic remains fragmental. In France, the Daubrée statistics (1908) and agricultural statistics (1892, 1929) formed fundamental material to fill this gap. Aims: Release, test, and summarize the digitalized dataset. Analyze long-term forest changes in forest area, composition, and structure. Methods: Primary data on forest area across NUTS-3 geographic units, split by forest management and ownership categories and dominating tree species (Daubrée), were digitized and cross-compared. Centennial changes in forest attributes were assessed from modern forest inventory data. Results: Cross-comparison revealed: (1) strong temporal consistency in forest changes over time, (2) systematic and interpretable biases in ownership/management categories between Daubrée and agricultural statistics. Strong shift from coppices to high forests, increased prevalence of private ownership, and constant proportion of broadleaf- and conifer-dominated forests were highlighted, with increased tree species diversity at country scale. Conclusion: Ancient statistics are shown to play a major role in retrospective land-use and forest policy analysis.

ano.nymous@ccsd.cnrs.fr.invalid (Timothée Audinot) 09 Aug 2021

https://hal.science/hal-03317972v1

[hal-02544285] La croissance des forêts et les changements environnementaux

Les forêts de l’hémisphère nord sont plus productives qu’il y a plusieurs décennies. Telle est la tendance observée et quantifiée dans différentes études menées depuis les années 1970 et qui mettent en cause plusieurs facteurs : les modifications des régimes pluviothermiques, les dépôts azotés et l’augmentation de la concentration atmosphérique en dioxyde de carbone. À partir de données de l’inventaire forestier national, les auteurs de cet article se sont penchéssur l’évolution des forêts françaises. Leurs résultats à des échelles plus fines mettent en évidence des variations extrêmes (négative et positive) liées aux espèces et au contexte environnemental local qu’il conviendrait de suivre en « temps réel » compte tenu des grandes incertitudes futures liées au climat.

ano.nymous@ccsd.cnrs.fr.invalid (François F. Lebourgeois) 21 Apr 2020

https://hal.science/hal-02544285v1

[hal-02931277] A Machine-Learning Approach for Classifying Defects on Tree Trunks using Terrestrial LiDAR

Three-dimensional data are increasingly prevalent in forestry thanks to terrestrial LiDAR. This work assesses the feasibility for an automated recognition of the type of local defects present on the bark surface. These sin-gularities are frequently external markers of inner defects affecting wood quality, and their type, size, and frequency are major components of grading rules. The proposed approach assigns previously detected abnormalities in the bark roughness to one of the defect types: branches, branch scars, epi-cormic shoots, burls, and smaller defects. Our machine learning approach is based on random forests using potential defects shape descriptors, including Hu invariant moments, dimensions, and species. The results of our experiments involving different French commercial species, oak, beech, fir, and pine showed that most defects were well classified with an average F 1 score of 0.86.

ano.nymous@ccsd.cnrs.fr.invalid (Van-Tho Nguyen) 05 Sep 2020

https://hal.science/hal-02931277v1

[hal-03085655] Unprecedented pluri-decennial increase in the growing stock of French forests is persistent and dominated by private broadleaved forests

& Key message French forests exhibit the fastest relative changes across Europe. Growing stock increases faster than area, and is greatest in low-stocked private broadleaved forests. Past areal increases and current GS levels show positive effects on GS expansion, with GS increases hence expected to persist. & Context Strong increases in growing stocks (GS) of European forests for decades remain poorly understood and of unknown duration. French forests showing the greatest relative changes across Europe form the investigated case study. & Aims The magnitudes of net area, GS, and GS density (GSD) changes were evaluated across forest categories reflecting forest policy and land-use drivers. The roles of forest areal changes, GS and GSD levels on GS changes were investigated. & Methods National Forest Inventory data were used to produce time series of area, GS and GSD across forest categories over 1976–2014, and exploratory causal models of GS changes. & Results GS (+ 57%) increased three times faster than area, highlighting an advanced stage in the forest transition. Low-stocked private forests exhibited strong changes in GS/GSD, greatest in private broadleaved forests, stressing the contribution of returning forests on abandoned lands. Regression models demonstrated positive effects of both past areal increases and current GS, on GS expansion. & Conclusion Aerial C-sink in French forests is expected to persist in future decades.

ano.nymous@ccsd.cnrs.fr.invalid (Jean-Daniel Bontemps) 21 Dec 2020

https://hal.science/hal-03085655v1

[hal-02942642] Sensitivity of gross primary productivity to climatic drivers during the summer drought of 2018 in Europe

In summer 2018, Europe experienced a record drought, but it remains unknown how the drought affected ecosystem carbon dynamics. Using observations from 34 eddy covariance sites in different biomes across Europe, we studied the sensitivity of gross primary productivity (GPP) to environmental drivers during the summer drought of 2018 versus the reference summer of 2016. We found a greater drought-induced decline of summer GPP in grass- lands (−38%) than in forests (−10%), which coincided with reduced evapotranspiration and soil water content (SWC). As com- pared to the ‘normal year’ of 2016, GPP in different ecosystems exhibited more negative sensitivity to summer air temperature (Ta) but stronger positive sensitivity to SWC during summer drought in 2018, that is, a stronger reduction of GPP with soil moisture deficit. We found larger negative effects of Ta and vapour pressure deficit (VPD) but a lower positive effect of photosynthetic photon flux density on GPP in 2018 compared to 2016, which contributed to reduced summer GPP in 2018. Our results demonstrate that high temperature-induced increases in VPD and decreases in SWC aggravated drought impacts on GPP.

ano.nymous@ccsd.cnrs.fr.invalid (Zheng Fu) 18 Sep 2020

https://hal.inrae.fr/hal-02942642v1

[hal-03006008] Soil properties explain tree growth and mortality, but not biomass, across phosphorus-depleted tropical forests

We observed strong positive relationships between soil properties and forest dynamics of growth and mortality across twelve primary lowland tropical forests in a phosphorus-poor region of the Guiana Shield. Average tree growth (diameter at breast height) increased from 0.81 to 2.1 mm yr−1 along a soil texture gradient from 0 to 67% clay, and increasing metal-oxide content. Soil organic carbon stocks in the top 30 cm ranged from 30 to 118 tons C ha−1, phosphorus content ranged from 7 to 600 mg kg−1 soil, and the relative abundance of arbuscular mycorrhizal fungi ranged from 0 to 50%, all positively correlating with soil clay, and iron and aluminum oxide and hydroxide content. In contrast, already low extractable phosphorus (Bray P) content decreased from 4.4 to <0.02 mg kg−1 in soil with increasing clay content. A greater prevalence of arbuscular mycorrhizal fungi in more clayey forests that had higher tree growth and mortality, but not biomass, indicates that despite the greater investment in nutrient uptake required, soils with higher clay content may actually serve to sustain high tree growth in tropical forests by avoiding phosphorus losses from the ecosystem. Our study demonstrates how variation in soil properties that retain carbon and nutrients can help to explain variation in tropical forest growth and mortality, but not biomass, by requiring niche specialization and contributing to biogeochemical diversification across this region.

ano.nymous@ccsd.cnrs.fr.invalid (Jennifer Soong) 24 Jun 2022

https://hal.science/hal-03006008v1

[hal-03040738] Towards a set of national forest inventory indicators to be used for assessing the conservation status of the habitats directive forest habitat types

Since the enactment of the EU Habitats Directive, the conservation status of forest habitat types, habitats of species, and species has become the central concept of the Directive's nature conservation legislation. Despite its role, it has drawn relatively little attention. Within a rather short research period, a few research papers have addressed the existing definitions, indicators for the conservation status assessment, and assessment techniques. This paper attempted to complete the set of measurable indicators available in national forest inventories and connect them with the forest habitat types’ conservation status components (area, function, structure, and prospects). A set of 40 indicators was defined, labelled with one or more of the four conservation status components and assessed with the quality dimensions. The analysis uncovered that five indicators could be used to assess the component of range and area, 20 that of structure, 22 that of function and 27 that of prospects. It also showed that conventional forestry indicators such as tree species, diameter at breast height, and regeneration are less sensitive regarding the data quality. Conversely, some typical biodiversity indicators lacked completeness, timeliness, and precision. In addition to this analysis, the data distributions (data for them were provided by the national forest inventories of Italy, Slovenia, and Spain) of some indicators were analysed. Based on all the results, it was also possible to conclude that there is a shortage of national forest inventory indicators for the assessments of the area and function conservation status components. While the area component should be described with the indicators of forest habitat type fragmentation, mingling and perforation with non-forest and other forest vegetation communities, the functional component is bereft of indicators describing processes such as biomass growth and carbon cycling. Future research should thus search for more indicators to represent all conservation status components in a more balanced way. More efforts should also be expended into the harmonisation of indicators.

ano.nymous@ccsd.cnrs.fr.invalid (Marko Kovac) 04 Dec 2020

https://hal.inrae.fr/hal-03040738v1

[hal-03038406] How does oak mast seeding affect the feeding behavior of sympatric red and roe deer?

Oak reproduction is characterized by mast seeding with high inter-annual fluctuations in fruit production. Such resource pulses can greatly affect ecosystem functioning and may cause seed consumers to alter their mobility, demography, or diet. Consequences of mast seeding for seed consumers remain poorly understood as their long timescale makes them difficult to study. We investigated impacts of oak mast seeding on the feeding behavior of two sympatric European deer species: red deer (Cervus elaphus) and roe deer (Capreolus capreolus). We analyzed their rumen content over a 31-year period in tandem with 10 years of data on oak fructification (i.e. 8 years of field monitoring and two modelled years). Acorn production is strongly correlated with consumption by both deer species. In years of high fructification, acorns represent more than 50% and 35% of red and roe deer diet, respectively, confirming assumptions that deer favor acorns when these are available. Red deer eat more acorns than roe deer both between and within years. High acorn production in mast years appears to saturate the capacity of deer to consume acorns. As the proportion of acorns increase in their diet, red deer eat more grasses and less conifer browse. No dietary shift was found for roe deer. By inducing dietary shifts in consumers, oak mast seeding can have cascading effects on ecosystem processes, notably on the damages on conifers caused by red deer and the consequences for forest dynamics.

ano.nymous@ccsd.cnrs.fr.invalid (Julien Barrere) 22 Aug 2022

https://hal.inrae.fr/hal-03038406v1

[hal-03794287] A la recherche de la structure d'attache entre la truffe d'été et son hôte

[...]

ano.nymous@ccsd.cnrs.fr.invalid (Aurélie Deveau) 03 Oct 2022

https://hal.inrae.fr/hal-03794287v1

[hal-02948753] The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., >= 10 cm diameter at breast height) abundance relative to co-occurring non-palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long-term climate stability. Life-form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non-tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above-ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.

ano.nymous@ccsd.cnrs.fr.invalid (Robert Muscarella) 09 Nov 2020

https://hal.inrae.fr/hal-02948753v1

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Productions 2020

HAL : Dernières publications

[hal-03048264] EUNIS Habitat Classification: Expert system, characteristic species combinations and distribution maps of European habitats

[hal-03048253] Vegetation unit assignments: phytosociology experts and classification programs show similar performance but low convergence

[hal-02434220] TRY plant trait database – enhanced coverage and open access

[hal-02650649] Long-term thermal sensitivity of Earth’s tropical forests

[hal-03778635] The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

[hal-02996232] Unraveling the relative role of light and water competition between lianas and trees in tropical forests

[hal-02948750] Validation of Space-based albedo products from upscaled tower-based measurements over Heterogeneous and Homogeneous landscapes

[hal-03045938] Natura 2000 forest habitats: climatic debt in lowlands and thermophilization in highlands

[hal-02948795] A portable, low-cost relaxed eddy accumulation (REA) system for quantifying ecosystem-level fluxes of volatile organics

[hal-02948749] The global distribution of leaf chlorophyll content

[hal-03038558] Dernières innovations sur la plantation forestière. Contribution de la R&D pour accompagner les évolutions attendues dans les pratiques

[hal-02963149] Le profil cultural : une méthode d'observation pour analyser les impacts de la préparation mécanisée du site sur la structure du sol

[hal-03037487] Cultivation profile: a visual evaluation method of soil structure adapted to the analysis of the impacts of mechanical site preparation in forest plantations

[hal-02544340] Comment l'Office national des forêts anticipe les effets du changement climatique ?

[hal-03179773] Temporal trends in tree defoliation and response to multiple biotic and abiotic stresses

[hal-03051411] Energy, water and carbon exchanges in managed forest ecosystems: description, sensitivity analysis and evaluation of the INRAE GO+ model, version 3.0

[hal-02541780] Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling

[hal-03005990] Tree mode of death and mortality risk factors across Amazon forests

[hal-02948828] Microgeographic local adaptation and ecotype distributions: The role of selective processes on early life‐history traits in sympatric, ecologically divergent Symphonia populations

[hal-02995533] Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites

[hal-02959147] Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads

[hal-02948755] Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests

[hal-02948747] Contrasting patterns of tree species mixture effects on wood δ13C along an environmental gradient

[hal-02927318] How does contemporary selection shape oak phenotypes?

[hal-02870299] Which oak provenances for the 22nd century in Western Europe? Dendroclimatology in common gardens

[hal-03207504] Altered energy partitioning across terrestrial ecosystems in the European drought year 2018

[hal-02652095] Decreasing stand density favors resistance, resilience, and recovery of Quercus petraea trees to a severe drought, particularly on dry sites

[hal-03029648] Diversity and potentiality of multi-criteria decision analysis methods for agri-food research

[hal-03040730] In situ estimation of genetic variation of functional and ecological traits in Quercus petraea and Q. robur

[hal-02610246] Species mixing reduces drought susceptibility of Scots pine (Pinus sylvestris L.) and oak (Quercus robur L., Quercus petraea (Matt.) Liebl.) - Site water supply and fertility modify the mixing effect

[hal-02610238] Stand growth and structure of mixed-species and monospecific stands of Scots pine (Pinus sylvestris L.) and oak (Q. robur L., Quercus petraea (Matt.) Liebl.) analysed along a productivity gradient through Europe

[hal-03014264] Snow cover duration trends observed at sites and predicted by multiple models

[hal-03040751] New developments in understanding plant water transport under drought stress

[hal-03365826] Assessing the dominant height of oriental beech (Fagus orientalis L.) in relation to edaphic and physiographic variables in the Hyrcanian Forests of Iran

[hal-02978675] Perspectives d'émergence d'une filière forêt-chimie des extractibles Points de vue des acteurs du Nord-Est de la France et du Sud-Ouest de l'Allemagne

[hal-03006193] The pantropical response of soil moisture to El Niño

[hal-02527995] Distribution of soil properties along forest-grassland interfaces: Influence of permanent environmental factors or land-use after-effects?

[hal-02949790] A standard protocol for reporting species distribution models

[hal-03206201] Valuation de la ressource territoriale et formes de circularité : la labellisation dans la filière forêt-bois française (Alpes, Jura, Vosges)

[hal-02534416] Selecting for water use efficiency, wood chemical traits and biomass with genomic selection in a Eucalyptus breeding program

[hal-03317972] Ancient forest statistics provide centennial perspective over the status and dynamics of forest area in France

[hal-02544285] La croissance des forêts et les changements environnementaux

[hal-02931277] A Machine-Learning Approach for Classifying Defects on Tree Trunks using Terrestrial LiDAR

[hal-03085655] Unprecedented pluri-decennial increase in the growing stock of French forests is persistent and dominated by private broadleaved forests

[hal-02942642] Sensitivity of gross primary productivity to climatic drivers during the summer drought of 2018 in Europe

[hal-03006008] Soil properties explain tree growth and mortality, but not biomass, across phosphorus-depleted tropical forests

[hal-03040738] Towards a set of national forest inventory indicators to be used for assessing the conservation status of the habitats directive forest habitat types

[hal-03038406] How does oak mast seeding affect the feeding behavior of sympatric red and roe deer?

[hal-03794287] A la recherche de la structure d'attache entre la truffe d'été et son hôte

[hal-02948753] The global abundance of tree palms