2019 - UMR Silva

[hal-02352504] The effect of tree diversity on the resistance and recovery of forest stands in the French Alps may depend on species differences in hydraulic features

As climate change should lead to an increase in the vulnerability and the sensitivity of forests to extreme climatic events, quantifying and predicting their response to more severe droughts remains a key task for foresters. Furthermore, recent works have suggested that tree diversity may affect forest ecosystem functioning, including their response to extreme events. In this study we aimed at testing whether the growth response of forest stands to stressful climatic events varied between mixed and monospecific stands, under various environmental conditions. We focused on beech-fir forests (Fagus sylvatica [L.] and Abies albs [L.]) and beech-oak forests (F. sylvatica [L.] and Quercus pubescent [L.]) in the French Alps. We used a dendrochronological dataset sampled in forest plots organized by triplets (one mixture and two monospecific stands) distributed in six sites along a latitudinal gradient. We tested (1) whether stand diversity (two-species stands vs monospecific stands) modulates the stands' response to drought events in terms of productivity, (2) whether species identity may drive the diversity effect on resistance and recovery, and (3) whether this can be explained by interspecific interactions. We found that (1) interspecific differences in response to extreme drought events (possibly due to interspecific differences in hydraulic characteristics) can induce a mixture effect on stand growth, although it appeared (2) to be strongly depending on species identity (positive effect only found for beech-fir mixed stands), while (3) there were no significant non-additive effects of diversity on stand resistance and recovery, except for some specific cases. Overall, our study shows that promoting selected mixed stands management may buffer extreme drought effect on stand productivity.

ano.nymous@ccsd.cnrs.fr.invalid (Marion Jourdan) 20 Jul 2022

https://hal.science/hal-02352504v1

[hal-02501278] Wood formation and tree adaptation to climate

This special issue of Annals of Forest Science compiles ten papers on “Wood formation and tree adaptation to climate”, which were presented at “Le Studium” International Conference in May 2018 in Orléans (France). These papers present observational, experimental and modelling studies investigating the influence of climatic changes on tree growth from the hour to the century, and from the cell to the landscape

ano.nymous@ccsd.cnrs.fr.invalid (Cyrille Rathgeber) 06 Mar 2020

https://hal.science/hal-02501278v1

[hal-02263853] Annotation data about multi criteria assessment methods used in the agri-food research: The French national institute for agricultural research (INRA) experience

This data article contains annotation data characterizing MultiCriteria Assessment (MCA) Methods proposed in the agri-food sector by researchers from INRA, Europe's largest agricultural research institute (INRA, http://institut.inra.fr/en). MCA can be used to assess and compare agricultural and food systems, and support multi-actor decision making and design of innovative systems for crop production, animal production and processing of agricultural products. These data are stored in a public repository managed by INRA (https://data.inra.fr/; https://doi.org/10.15454/WB51LL).

ano.nymous@ccsd.cnrs.fr.invalid (Geneviève Gésan-Guiziou) 05 Aug 2019

https://hal.science/hal-02263853v1

[hal-02921264] Effects of organic inputs derived from pea and wheat root functional traits on soil protease activities

Legume-derived organic inputs such as crop residues or compounds derived from rhizodeposition can influence soil microbial activities implicated in the degradation of organic N. Crops succeeding legumes can also be important drivers of such microbial activities, and trait-based approaches can be employed to better understand the influence of plants on soil microbial activities. The objective of this study was to examine the effects of organic inputs (rhizodeposits and crop residues) of previously planted pea together with wheat root traits on soil protease activities. We measured soil protease activities, soil variables describing C and N availability and microbial biomass N and wheat root functional traits related to resource acquisition and rhizodeposition at 5 wheat developmental stages. Soil protease activities were significantly increased by the addition of pea crop residues, whereas previous pea cropping (i.e., soil containing organic inputs derived from pea rhizodeposition) did not influence these activities. The percentage of fine roots < 0.1 mm in diameter was the only root trait that contributed to variation in soil protease activities. Other belowground traits related to plant nutrient competitive abilities (specific root length, root N uptake, root biomass, and hot water-extractable root N) did not influence soil protease activities. We showed that pea crop residues, acting as substrates, are the main drivers of soil protease activities. However, our results highlight the importance of considering fine roots to understand the effects of plants on soil microbial activities implicated in N mineralization.

ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Romillac) 25 Aug 2020

https://hal.science/hal-02921264v1

[hal-02154447] First evidences that the ectomycorrhizal fungus Paxillus involutus mobilizes nitrogen and carbon from saprotrophic fungus necromass

Fungal succession in rotting wood shows a surprising abundance of ectomycorrhizal (EM) fungi during the late decomposition stages. To better understand the links between EM fungi and saprotrophic fungi, we investigated the potential capacities of the EM fungus Paxillus involutus to mobilize nutrients from necromass of Postia placenta, a wood rot fungus, and to transfer these elements to its host tree. In this aim, we used pure cultures of P. involutus in the presence of labelled Postia necromass (15N/13C) as nutrient source, and a monoxenic mycorrhized pine experiment composed of labelled Postia necromass and P. involutus culture in interaction with pine seedlings. The isotopic labelling was measured in both experiments. In pure culture, P. involutus was able to mobilize N, but C as well, from the Postia necromass. In the symbiotic interaction experiment, we measured high 15N enrichments in all plant and fungal compartments. Interestingly, 13C remains mainly in the mycelium and mycorrhizas, demonstrating that the EM fungus transferred essentially N from the necromass to the tree. These observations reveal that fungal organic matter could represent a significant N source for EM fungi and trees, but also a C source for mycorrhizal fungi, including in symbiotic lifestyle.

ano.nymous@ccsd.cnrs.fr.invalid (Emila Akroume) 12 Jun 2019

https://hal.science/hal-02154447v1

[hal-02165403] Infiltration from the Pedon to Global Grid Scales: An Overview and Outlook for Land Surface Modeling

Infiltration in soils is a key process that partitions precipitation at the land surface into surface runoff and water that enters the soil profile. We reviewed the basic principles of water infiltration in soils and we analyzed approaches commonly used in land surface models (LSMs) to quantify infiltration as well as its numerical implementation and sensitivity to model parameters. We reviewed methods to upscale infiltration from the point to the field, hillslope, and grid cell scales of LSMs. Despite the progress that has been made, upscaling of local-scale infiltration processes to the grid scale used in LSMs is still far from being treated rigorously. We still lack a consistent theoretical framework to predict effective fluxes and parameters that control infiltration in LSMs. Our analysis shows that there is a large variety of approaches used to estimate soil hydraulic properties. Novel, highly resolved soil information at higher resolutions than the grid scale of LSMs may help in better quantifying subgrid variability of key infiltration parameters. Currently, only a few LSMs consider the impact of soil structure on soil hydraulic properties. Finally, we identified several processes not yet considered in LSMs that are known to strongly influence infiltration. Especially, the impact of soil structure on infiltration requires further research. To tackle these challenges and integrate current knowledge on soil processes affecting infiltration processes into LSMs, we advocate a stronger exchange and scientific interaction between the soil and the land surface modeling communities.

ano.nymous@ccsd.cnrs.fr.invalid (Harry Vereecken) 25 Jun 2019

https://hal.sorbonne-universite.fr/hal-02165403v1

[hal-02179547] Introduction to the invited issue on phloem function and dysfunction

Introduction to the invited issue on phloem function and dysfunction

ano.nymous@ccsd.cnrs.fr.invalid (Daniel Epron) 10 Jul 2019

https://hal.science/hal-02179547v1

[hal-02178452] Drought impacts on tree phloem

On-going climate change is increasing the risk of drought stress across large areas worldwide. Such drought events decrease ecosystem productivity and have been increasingly linked to tree mortality. Understanding how trees respond to water shortage is key to predicting the future of ecosystem functions. Phloem is at the core of the tree functions, moving resources such as non-structural carbohydrates, nutrients, and defence and information molecules across the whole plant. Phloem function and ability to transport resources is tightly controlled by the balance of carbon and water fluxes within the tree. As such, drought is expected to impact phloem function by decreasing the amount of available water and new photoassimilates. Yet, the effect of drought on the phloem has received surprisingly little attention in the last decades. Here we review existing knowledge on drought impacts on phloem transport from loading and unloading processes at cellular level to possible effects on long-distance transport and consequences to ecosystems via ecophysiological feedbacks. We also point to new research frontiers that need to be explored to improve our understanding of phloem function under drought. In particular, we show how phloem transport is affected differently by increasing drought intensity, from no response to a slowdown, and explore how severe drought might actually disrupt the phloem transport enough to threaten tree survival. Because transport of resources affects other organisms interacting with the tree, we also review the ecological consequences of phloem response to drought and especially predatory, mutualistic and competitive relations. Finally, as phloem is the main path for carbon from sources to sink, we show how drought can affect biogeochemical cycles through changes in phloem transport. Overall, existing knowledge is consistent with the hypotheses that phloem response to drought matters for understanding tree and ecosystem function. However, future research on a large range of species and ecosystems is urgently needed to gain a comprehensive understanding of the question.

ano.nymous@ccsd.cnrs.fr.invalid (Yann Salmon) 09 Jul 2019

https://hal.science/hal-02178452v1

[hal-02178457] The impact of prolonged drought on phloem anatomy and phloem transport in young beech trees

Phloem failure has recently been recognized as one of the mechanisms causing tree mortality under drought, though direct evidence is still lacking. We combined 13C pulse-labelling of 8-year-old beech trees (Fagus sylvatica L.) growing outdoors in a nursery with an anatomical study of the phloem tissue in their stems to examine how drought alters carbon transport and phloem transport capacity. For the six trees under drought, predawn leaf water potential ranged from -0.7 to -2.4 MPa, compared with an average of -0.2 MPa in five control trees with no water stress. We also observed a longer residence time of excess 13C in the foliage and the phloem sap in trees under drought compared with controls. Compared with controls, excess 13C in trunk respiration peaked later in trees under moderate drought conditions and showed no decline even after 4 days under more severe drought conditions. We estimated higher phloem sap viscosity in trees under drought. We also observed much smaller sieve-tube radii in all drought-stressed trees, which led to lower sieve-tube conductivity and lower phloem conductance in the tree stem. We concluded that prolonged drought affected phloem transport capacity through a change in anatomy and that the slowdown of phloem transport under drought likely resulted from a reduced driving force due to lower hydrostatic pressure between the source and sink organs.

ano.nymous@ccsd.cnrs.fr.invalid (Masako Dannoura) 09 Jul 2019

https://hal.science/hal-02178457v1

[hal-02178455] Estimation of phloem carbon translocation belowground at stand level in a hinoki cypress stand

At stand level, carbon translocation in tree stems has to match canopy photosynthesis and carbohydrate requirements to sustain growth and the physiological activities of belowground sinks. This study applied the Hagen-Poiseuille equation to the pressure-flow hypothesis to estimate phloem carbon translocation and evaluate what percentage of canopy photosynthate can be transported belowground in a hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.) stand. An anatomical study revealed that, in contrast to sieve cell density, conductive phloem thickness and sieve cell hydraulic diameter at 1.3 m in height increased with increasing tree diameter, as did the concentration of soluble sugars in the phloem sap. At tree level, hydraulic conductivity increased by two orders of magnitude from the smallest to the largest trees in the stand, resulting in a stand-level hydraulic conductance of 1.7 × 10-15 m Pa-1 s-1. The osmotic potential of the sap extracted from the inner bark was -0.75 MPa. Assuming that phloem water potential equalled foliage water potential at predawn, the turgor pressure in the phloem at 1.3 m in height was estimated at 0.22 MPa, 0.59 MPa lower than values estimated in the foliage. With this maximal turgor pressure gradient, which would be lower during day-time when foliage water potential drops, the estimated stand-level rate of carbon translocation was 2.0 gC m-2 day-1 (30% of daily gross canopy photosynthesis), at a time of the year when aboveground growth and related respiration is thought to consume a large fraction of photosynthate, at the expense of belowground activity. Despite relying on some assumptions and approximations, this approach, when coupled with measurements of canopy photosynthesis, may further be used to provide qualitative insight into the seasonal dynamics of belowground carbon allocation.

ano.nymous@ccsd.cnrs.fr.invalid (Daniel Epron) 09 Jul 2019

https://hal.science/hal-02178455v1

[hal-02628125] Are mixed-tree plantations including a nitrogen-fixing species more productive than monocultures?

The inclusion of N2-fixing tree species in tree plantations has the potential to increase biomass production compared to monocultures. Both successes and failures have been described in the literature; however, it is still difficult to distinguish a general pattern and to disentangle the factors influencing the mixture effect. The first objective of this study was to provide an overview of the published data on the effect of the introduction of N2-fixing trees in tree plantations through a meta-analysis approach and to calculate a mean effect of mixed-tree plantations on biomass production compared to monocultures of the non N2-fixing species in stands 2–20 years of age. The second objective was to evaluate the effects of (1) climate zone (temperate vs. tropical), (2) the species used (eucalypts vs. other non N2-fixing species, and leguminous tree species vs. other N2-fixing species), (3) the proportion of N2-fixing species compared to the non-fixing species, and (4) plant developmental stage. A total of 148 case studies from 34 experimental plantations under tropical (68 case studies) and temperate (80 case studies) conditions were identified from the literature. The global mixture effect was significantly positive, mixed-tree plantations being 18% more productive than the non N2-fixing monocultures, and this effect was significantly different from zero under temperate conditions (24% more productive) but not under tropical conditions (12% more productive). Indeed, the sites where the positive mixture effect was significantly different from zero were mostly located in a temperate climate, where soil nitrogen is generally considered less available than in tropical latitudes. Intermediate and high proportions of N2-fixing species gave similar positive results (27% more productive), while low proportions had no significant impact. Neither plantation age nor type of N2-fixing species (legume trees vs. other N2-fixing species) had any significant effect. In conclusion, it appears that climate is the main factor influencing the success of the mixture; however, it also seems that the degree of mixture success is more marked on sites with low biomass production where the monoculture is the least productive.

ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Marron) 22 Oct 2021

https://hal.inrae.fr/hal-02628125v1

[hal-02629130] Identifying the tree species compositions that maximize ecosystem functioning in European forests

1. Forest ecosystem functioning generally benefits from higher tree species richness, but variation within richness levels is typically large. This is mostly due to the contrasting performances of communities with different compositions. Evidencebased understanding of composition effects on forest productivity, as well as on multiple other functions will enable forest managers to focus on the selection of species that maximize functioning, rather than on diversity per se. 2. We used a dataset of 30 ecosystem functions measured in stands with different species richness and composition in six European forest types. First, we quantified whether the compositions that maximize annual above-ground wood production (productivity) generally also fulfil the multiple other ecosystem functions (multifunctionality). Then, we quantified the species identity effects and strength of interspecific interactions to identify the “best” and “worst” species composition for multifunctionality. Finally, we evaluated the real-world frequency of occurrence of best and worst mixtures, using harmonized data from multiple national forest inventories. 3. The most productive tree species combinations also tended to express relatively high multifunctionality, although we found a relatively wide range of compositions with high- or low-average multifunctionality for the same level of productivity. Monocultures were distributed among the highest as well as the lowest performing compositions. The variation in functioning between compositions was generally driven by differences in the performance of the component species and, to a lesser extent, by particular interspecific interactions. Finally, we found that the most frequent species compositions in inventory data were monospecific stands and that the most common compositions showed below-average multifunctionality and productivity. 4. Synthesis and applications. Species identity and composition effects are essential to the development of high-performing production systems, for instance in forestry and agriculture. They therefore deserve great attention in the analysis and design of functional biodiversity studies if the aim is to inform ecosystem management. A management focus on tree productivity does not necessarily trade-off against other ecosystem functions; high productivity and multifunctionality can be combined with an informed selection of tree species and species combinations.

ano.nymous@ccsd.cnrs.fr.invalid (Lander Baeten) 29 Dec 2024

https://hal.inrae.fr/hal-02629130v1

[hal-02184243] Geographical adaptation prevails over species-specific determinism in trees' vulnerability to climate change at Mediterranean rear-edge forests

Climate change may reduce forest growth and increase forest mortality, which is connected to high carbon costs through reductions in gross primary production and net ecosystem exchange. Yet, the spatiotemporal patterns of vulnerability to both short-term extreme events and gradual environmental changes are quite uncertain across the species' limits of tolerance to dryness. Such information is fundamental for defining ecologically relevant upper limits of species tolerance to drought and, hence, to predict the risk of increased forest mortality and shifts in species composition. We investigate here to what extent the impact of short- and long-term environmental changes determines vulnerability to climate change of three evergreen conifers (Scots pine, silver fir, Norway spruce) and two deciduous hardwoods (European beech, sessile oak) tree species at their southernmost limits of distribution in the Mediterranean Basin. Finally, we simulated future forest growth under RCP 2.6 and 8.5 emission scenarios using a multispecies generalized linear mixed model. Our analysis provides four key insights into the patterns of species' vulnerability to climate change. First, site climatic marginality was significantly linked to the growth trends: increasing growth was related to less climatically limited sites. Second, estimated species-specific vulnerability did not match their a priori rank in drought tolerance: Scots pine and beech seem to be the most vulnerable species among those studied despite their contrasting physiologies. Third, adaptation to site conditions prevails over species-specific determinism in forest response to climate change. And fourth, regional differences in forests vulnerability to climate change across the Mediterranean Basin are linked to the influence of summer atmospheric circulation patterns, which are not correctly represented in global climate models. Thus, projections of forest performance should reconsider the traditional classification of tree species in functional types and critically evaluate the fine-scale limitations of the climate data generated by global climate models.

ano.nymous@ccsd.cnrs.fr.invalid (Isabel Dorado-Liñán) 15 Jul 2019

https://hal.science/hal-02184243v1

[hal-02625305] Chilling and forcing temperatures interact to predict the onset of wood formation in Northern Hemisphere conifers

The phenology of wood formation is a critical process to consider for predicting how trees from the temperate and boreal zones may react to climate change. Compared to leaf phenology, however, the determinism of wood phenology is still poorly known. Here, we compared for the first time three alternative ecophysiological model classes (threshold models, heat-sum models and chilling-influenced heat-sum models) and an empirical model in their ability to predict the starting date of xylem cell enlargement in spring, for four major Northern Hemisphere conifers (Larix decidua, Pinus sylvestris, Picea abies and Picea mariana). We fitted models with Bayesian inference to wood phenological data collected for 220 site-years over Europe and Canada. The chilling-influenced heat-sum model received most support for all the four studied species, predicting validation data with a 7.7-day error, which is within one day of the observed data resolution. We conclude that both chilling and forcing temperatures determine the onset of wood formation in Northern Hemisphere conifers. Importantly, the chilling-influenced heat-sum model showed virtually no spatial bias whichever the species, despite the large environmental gradients considered. This suggests that the spring onset of wood formation is far less affected by local adaptation than by environmentally driven plasticity. In a context of climate change, we therefore expect rising winter-spring temperature to exert ambivalent effects on the spring onset of wood formation, tending to hasten it through the accumulation of forcing temperature, but imposing a higher forcing temperature requirement through the lower accumulation of chilling.

ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Delpierre) 04 Apr 2024

https://hal.inrae.fr/hal-02625305v1

[hal-02168619] Nondestructive and Fast Vibration Phenotyping of Plants

The frequencies of free oscillations of plants, or plant parts, depend on their geometries, stiffnesses, and masses. Besides direct biomechanical interest, free frequencies also provide insights into plant properties that can usually only be measured destructively or with low-throughput techniques (e.g., change in mass, tissue density, or stiffness over development or with stresses). We propose here a new high-throughput method based on the noncontact measurements of the free frequencies of the standing plant. The plant is excited by short air pulses (typically 100 ms). The resulting motion is recorded by a high speed video camera (100 fps) and processed using fast space and time correlation algorithms. In less than a minute the mechanical behavior of the plant is tested over several directions. The performance and versatility of this method has been tested in three contrasted species: tobacco (Nicotiana benthamian), wheat (Triticum aestivum L.), and poplar (Populus sp.), for a total of more than 4000 data points. In tobacco we show that water stress decreased the free frequency by 15%. In wheat we could detect variations of less than 1 g in the mass of spikes. In poplar we could measure frequencies of both the whole stem and leaves. The work provides insight into new potential directions for development of phenotyping.

ano.nymous@ccsd.cnrs.fr.invalid (Emmanuel de Langre) 28 Jun 2019

https://hal.science/hal-02168619v1

[hal-02622295] Massive postglacial gene flow between European white oaks uncovered genes underlying species barriers

Oaks are dominant forest tree species widely distributed across the Northern Hemisphere, where they constitute natural resources of economic, ecological, social and historical value. Hybridisation and adaptive introgression have long been thought to be major drivers of their ecological success. Therefore, the maintenance of species barriers remains a key question, given the extent of interspecific gene flow. In this study, we made use of the tremendous genetic variation among four European white oak species (31 million single nucleotide polymorphisms (SNPs)) to infer the evolutionary history of these species, study patterns of genetic differentiation and identify reproductive barriers. We first analysed the ecological and historical relationships among these species and inferred a long-term strict isolation followed by a recent and extensive postglacial contact using approximate Bayesian computation. Assuming this demographic scenario, we then performed backward simulations to generate the expected distributions of differentiation under neutrality to scan their genomes for reproductive barriers. We finally identified important intrinsic and ecological functions driving the reproductive isolation. We discussed the importance of identifying the genetic basis for the ecological preferences between these oak species and its implications for the renewal of European forests under global warming.

ano.nymous@ccsd.cnrs.fr.invalid (Thibault Leroy) 07 Dec 2023

https://hal.inrae.fr/hal-02622295v1

[hal-02384139] Fructification du Hêtre et des Chênes en France : rôle des températures, du pollen et du bilan de carbone et relation avec la croissance des peuplements

Dans cette étude, nous avons analysé les déterminants environnementaux de la variabilité spatiale et temporelle de la fructification des trois espèces feuillues européennes majeures : Quercus robur, Quercus petraea et Fagus sylvatica. Nous avons étudié les relations entre la production de fruits, l’émission de pollen, les ressources carbonées et hydriques et les conditions climatiques sur la période 1994-2007 (14 ans) à partir de 48 peuplements du réseau RENECOFOR. La production moyenne des fruits est de 251 kg/ha/an pour les Chênes et de 174 kg/ha/an pour le Hêtre. Pour le Hêtre, la production suit un rythme bisannuel très net et est synchrone entre les sites. Elle apparaît beaucoup plus variable pour les Chênes sans synchronisme net. Pour les Chênes, la fructification dépend très fortement des conditions thermiques durant la période d’émission du pollen (début avril) confirmant l’hypothèse du synchronisme pollinique pour ces espèces. Pour le Hêtre, la production dépend très fortement des écarts de température estivale entre les années. Pour les deux espèces, les relations entre la production de fruits et les différents déterminants suivent des lois non linéaires avec des forts effets seuil et des interactions complexes. Enfin, pour le Hêtre, la croissance radiale est réduite en cas de forte fructification alors que les années de bonne glandée sont aussi des années de forte croissance pour les Chênes. Les deux espèces présentent donc deux comportements opposés concernant les stratégies d’allocation entre la croissance radiale et la production de fruits.

ano.nymous@ccsd.cnrs.fr.invalid (François F. Lebourgeois) 28 Nov 2019

https://agroparistech.hal.science/hal-02384139v1

[hal-02181076] Air temperature optima of vegetation productivity across global biomes.

The global distribution of the optimum air temperature for ecosystem-level gross primary productivity ([Formula: see text]) is poorly understood, despite its importance for ecosystem carbon uptake under future warming. We provide empirical evidence for the existence of such an optimum, using measurements of in situ eddy covariance and satellite-derived proxies, and report its global distribution. [Formula: see text] is consistently lower than the physiological optimum temperature of leaf-level photosynthetic capacity, which typically exceeds 30 °C. The global average [Formula: see text] is estimated to be 23 ± 6 °C, with warmer regions having higher [Formula: see text] values than colder regions. In tropical forests in particular, [Formula: see text] is close to growing-season air temperature and is projected to fall below it under all scenarios of future climate, suggesting a limited safe operating space for these ecosystems under future warming.

ano.nymous@ccsd.cnrs.fr.invalid (Mengtian Huang) 11 Jul 2019

https://hal.science/hal-02181076v1

[hal-02373054] Biomasse microbienne carbonée et activités enzymatiques : gammes de valeurs obtenues pour différents sols agricoles français et belges

Depuis plusieurs décennies, les micro-organismes du sol ont été identifiés comme des acteurs majeurs du fonctionnement des sols et certaines variables microbiennes (abondance, diversité et activités) sont utilisées pour évaluer la qualité biologique des sols. Plus particulièrement, les activités enzymatiques d’origine microbienne impliquées dans la minéralisation des matières organiques des sols suscitent un fort intérêt ; néanmoins, aucun référentiel n’existe actuellement afin de les utiliser comme des indicateurs prédictifs des fonctions inhérentes à la fertilité des sols agricoles. Dans ce contexte, nous avons mesuré six activités enzymatiques (protéases, arginine- et leucine- aminopeptidases, β-glucosidases, phosphatases acides, arylsulfatases) impliquées dans la décomposition / minéralisation des matières organiques du sol, ainsi que la biomasse microbienne, sur six dispositifs expérimentaux situés dans différents contextes pédoclimatiques français et belges. Les résultats obtenus confirment que la gamme de valeurs d’activités enzymatiques et de biomasse microbienne mesurées pour différents types de sols est très large. Ainsi, les moyennes par dispositif des activités enzymatiques (exprimées par gramme de sol) varient d’un facteur compris entre 2,7 (pour les protéases) et 9,7 (pour les arylsulfatases). Concernant le carbone de la biomasse microbienne, les moyennes par dispositif varient de 159 à 488 µg C g-1 sol. Nos résultats montrent que cette biomasse microbienne, exprimée comme une fraction du carbone organique du sol, varie de 1,5 à 3,1 %. Cette variabilité des activités enzymatiques et de la biomasse microbienne en fonction des sites apparaît fortement liée aux différences de caractéristiques physico-chimiques des sols, et certainement au mode d’occupation des sols. Notamment, les variables microbiennes mesurées sont toutes significativement corrélées, certaines positivement (protéases, arginine- et leucine- aminopeptidases, β-glucosidases, biomasse microbienne), d’autres négativement (phosphatases acides, arylsulfatases) à la teneur en argile du sol. Nos résultats confirment ainsi la nécessité de disposer, pour chaque type de sol, d’un référentiel de valeurs d’activités enzymatiques et de biomasse microbienne avant d’envisager le développement d’indicateurs de fertilité des sols basés sur ces métriques.

ano.nymous@ccsd.cnrs.fr.invalid (Caroline Petitjean) 25 Apr 2022

https://hal.science/hal-02373054v1

[hal-02384184] Les réponses observées des arbres aux variations du climat (croissance, phénologie foliaire et fructification)

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ano.nymous@ccsd.cnrs.fr.invalid (François Lebourgeois) 16 Jul 2024

https://agroparistech.hal.science/hal-02384184v1

[hal-02411666] The commonness of rarity: Global and future distribution of rarity across land plants

A key feature of life’s diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant diversity to quantify the fraction of Earth’s plant biodiversity that are rare. A large fraction, ~36.5% of Earth’s ~435,000 plant species, are exceedingly rare. Sampling biases and prominent models, such as neutral theory and the k-niche model, cannot account for the observed prevalence of rarity. Our results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth’s plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species. Estimates of global species abundance distributions have important implications for risk assessments and conservation planning in this era of rapid global change.

ano.nymous@ccsd.cnrs.fr.invalid (Brian Enquist) 31 May 2021

https://hal.science/hal-02411666v1

[hal-02399726] The cost of deer to trees: changes in resource allocation from growth-related traits and phenolic content to structural defence

Background and aims-Plants may use various defence mechanisms to protect their tissues against deer browsing and the allocation of resources to defence may trade-off with plants' growth. In a context of increasing deer populations in European forests, understanding the resource allocation strategies of trees is critical to better assess their ability to face an increasing browsing pressure. The aim of this study was to determine how deer removal affects the resource allocation to both defensive and growth-related traits in field conditions for three tree species (Abies alba, Picea abies and Fagus sylvatica). Methods-We compared eight pairs of fenced-unfenced plots to contrast plots with and without browsing pressure. The pairs were set up in 2005 and 2014 to compare different fencing duration. We measured leaf and shoot traits related to the defence against herbivores (phenolic content, structural resistance, C:N ratio) and to the investment in plants' growth and productivity (specific leaf area and nutrient content). Key results-For the three species, the structural resistance of leaves and shoots was negatively correlated with SLA, nutrient content and phenolic content. For Abies alba, exclusion of deer decreased shoot structural resistance in favour of higher nutrient content, SLA and phenolic content. The fencing duration had no effect on the different measured traits. Conclusions-Our results support the assumption of a trade-off between structural defence and growth-related traits at the intraspecific scale for the three studied species. We also confirmed the hypothesis that exposure to deer browsing is involved in the resource allocation of woody species. For Abies alba, fencing led to a change in resource allocation from structural defence to growth-related traits and chemical defence.

ano.nymous@ccsd.cnrs.fr.invalid (Julien Barrere) 09 Dec 2019

https://hal.science/hal-02399726v1

[hal-02320571] Quelle pertinence du modèle diversité-productivité-perturbations pour analyser l’influence des pratiques agricoles sur la diversité des prairies permanentes du Massif central ?

Un modèle a été réalisé pour évaluer l’impact des pratiques agricoles sur la diversité des prairies. Pour tester les prédictions d’un modèle théorique d’écologie, le modèle d’équilibre dynamique, nous avons suivi 18 prairies permanentes du Massif central aux pédoclimats et modes de gestion variés. Nous avons mis en évidence une diminution de la richesse spécifique liée à l’augmentation de la quantité de biomasse exportée (pâturée ou fauchée) et une diminution de la richesse fonctionnelle liée à l’augmentation de la productivité. Ces effets n’expliquent toutefois qu’une faible part de la variabilité observée entre sites. La quantité de biomasse exportée dépend du nombre de fauches et du chargement animal annuel ; la productivité était avant tout dépendante des précipitations durant la période d’étude, et non de la fertilisation. Nous discutons de l’intérêt et des limites de l’utilisation du modèle pour la gestion de la diversité des prairies.

ano.nymous@ccsd.cnrs.fr.invalid (Rémi Perronne) 18 Oct 2019

https://hal.science/hal-02320571v1

[hal-02432407] Large hydraulic safety margins protect Neotropical canopy rainforest tree species against hydraulic failure during drought

Abundant Neotropical canopy-tree species are more resistant to drought-induced branch embolism than what is currently admitted. Large hydraulic safety margins protect them from hydraulic failure under actual drought conditions.ContextXylem vulnerability to embolism, which is associated to survival under extreme drought conditions, is being increasingly studied in the tropics, but data on the risk of hydraulic failure for lowland Neotropical rainforest canopy-tree species, thought to be highly vulnerable, are lacking.AimsThe purpose of this study was to gain more knowledge on species drought-resistance characteristics in branches and leaves and the risk of hydraulic failure of abundant rainforest canopy-tree species during the dry season.MethodsWe first assessed the range of branch xylem vulnerability to embolism using the flow-centrifuge technique on 1-m-long sun-exposed branches and evaluated hydraulic safety margins with leaf turgor loss point and midday water potential during normal- and severe-intensity dry seasons for a large set of Amazonian rainforest canopy-tree species.ResultsTree species exhibited a broad range of embolism resistance, with the pressure threshold inducing 50% loss of branch hydraulic conductivity varying from − 1.86 to − 7.63 MPa. Conversely, we found low variability in leaf turgor loss point and dry season midday leaf water potential, and mostly large, positive hydraulic safety margins.ConclusionsRainforest canopy-tree species growing under elevated mean annual precipitation can have high resistance to embolism and are more resistant than what was previously thought. Thanks to early leaf turgor loss and high embolism resistance, most species have a low risk of hydraulic failure and are well able to withstand normal and even severe dry seasons.

ano.nymous@ccsd.cnrs.fr.invalid (Camille Ziegler) 14 Dec 2020

https://hal.umontpellier.fr/hal-02432407v1

[hal-02011754] Explaining the larger seed bank of an invasive shrub in non-native versus native environments by differences in seed predation and plant size

•Background and aims - Large, persistent seed banks contribute to the invasiveness of non-native plants, and maternal plant size is an important contributory factor. We explored the relationships between plant vegetative size (V) and soil seed bank size (S) for the invasive shrub (Ulex europaeus) in its native range and in non-native populations, and identified which other factors may contribute to seed bank variation between native and invaded regions. •Methods - We compared the native region (France) with two regions where Ulex is invasive, one with seed predators introduced for biological control (New Zealand) and another where seed predators are absent (La Réunion). We quantified seed bank size, plant dimensions, seed predation, and soil fertility for six stands in each of the three regions.•Key results - Seed banks were 9 to 14 times larger in the two invaded regions compared to native France. We found a positive relationship between current seed bank size and actual plant size, and that any deviation from this relationship was probably due to large differences in seed predation and/or soil fertility. We further identified three possible factors explaining larger seed banks in non-native environments: larger maternal plant size, lower activity of seed predators and higher soil fertility. •Conclusions - In highlighting a positive relationship between maternal plant size and seed bank size, and identifying additional factors that regulate soil seed bank dynamics in non-native ranges, our data offer a number of opportunities for invasive weed control. For non-native Ulex populations specifically, management focusing on 'S' (i.e. the reduction of the seed bank by stimulating germination, or the introduction of seed predators as biological control agents), and/or 'V' (i.e. by cutting mature stands to reduce maternal plant biomass) offers the most probable combination of effective control options.

ano.nymous@ccsd.cnrs.fr.invalid (Mark Bakker) 13 Feb 2019

https://hal.science/hal-02011754v1

[hal-02111822] Soils Drowned in Water Impoundments: A New Frontier

Water impoundments have major impacts on biogeochemical cycles at the local and global scales. However, although reservoirs flood soils, their biogeochemical evolution below water and its ecological consequences are very poorly documented. We took advantage of the complete emptying of the Guerlédan Reservoir (Brittany, France) to compare the composition of soils flooded for 84 years with that of adjacent non-flooded soils used as reference, in 3 situations contrasted by their soil type (Cambisol and Podzol) and initial land-use (forest or grassland). In the annual drawdown zone, upper horizons of submerged soils are eroded, especially near the upper shore and on slopes. In the permanently drowned area, silty sediments cover drowned soils. Compared to reference soils, forest soils drowned for 84 years maintain their original morphological differentiation, but colors are dull, and the humus (O horizons) have virtually disappeared. Spodic horizons are depleted in poorly crystallized iron minerals while the accumulation of amorphous aluminum compounds remains unchanged. Soil bulk density increases as well as pH while total phosphorus content is almost unchanged. On the other hand, the pH of drowned grassland soils is lower by almost one unit, and the total phosphorus content was halved compared to reference soils. In this context, in addition to the effects of flooding, differences are attributed to post-1950 changes in agricultural practices i.e., liming and fertilization. Organic matter stocks decrease by almost 40%. This rate is similar in Cambisols and Podzols. Assuming that carbon was lost as CO2 and CH4, the corresponding flux averaged over the reservoir’s life is close to global areal estimates of CO2 emissions in temperate reservoirs and offsets a significant proportion of the carbon burial in reservoir sediments. Hence, flooded soils contribute significantly to the GHG budget of reservoirs, provide original long-term experimental sites to measure the effects of anoxia on soils and contain archives of past soil properties.

ano.nymous@ccsd.cnrs.fr.invalid (Jim Félix-Faure) 26 Apr 2019

https://hal.science/hal-02111822v1

[hal-02118719] The influence of veneer thickness and knot proportion on the mechanical properties of laminated veneer lumber (LVL) made from secondary quality hardwood

The first objective of this work was to study the influence of veneer quality on the mechanical properties of laminated veneer lumber (LVL) made of secondary quality hardwood. The second objective was to propose an adapted veneer thickness that provides the optimum mechanical properties of LVL, taking the veneer properties into account. Forty-eight LVL panels glued together using polyvinyl acetate (PVAc) were prepared. The quality of fresh veneers was assessed by measuring veneer knot proportion, lathe check depth and lathe check interval. The static modulus of elasticity (MOE), dynamic MOE, modulus of rupture (MOR) and shear modulus were measured using destructive and non-destructive methods. The 3 mm thick veneer provided the optimum mechanical properties for LVL for both species. The test direction did not have any significant influence on the mechanical properties. In the flatwise direction, the average MOE values obtained were 13.2 GPa for beech LVL and 13.3 GPa for oak LVL, whereas the MOR was 72.0 MPa and 63.4 MPa, respectively. Increasing knot proportion in veneers results in a decrease in LVL MOE and MOR. Moreover, deeper lathe checks and higher lathe check intervals on veneer surfaces provide lower LVL shear modulus in the edgewise direction for both species. Internal veneer provides LVL with a higher density but weaker mechanical properties due to a higher knot proportion in the internal veneer.

ano.nymous@ccsd.cnrs.fr.invalid (Citra Yanto Ciki Purba) 03 May 2019

https://hal.science/hal-02118719v1

[hal-02943204] Importance of Detoxification Processes in Ozone Risk Assessment: Need to Integrate the Cellular Compartmentation of Antioxidants?

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ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Dusart) 22 Jul 2024

https://hal.science/hal-02943204v1

[hal-02623508] Impact of bias correction and downscaling through quantile mapping on simulated climate change signal: a case study over Central Italy

Quantile mapping (QM) represents a common post-processing technique used to connect climate simulations to impact studies at different spatial scales. Depending on the simulation-observation spatial scale mismatch, QM can be used for two different applications. The first application uses only the bias correction component, establishing transfer functions between observations and simulations at similar spatial scales. The second application includes a statistical downscaling component when point-scale observations are considered. However, knowledge of alterations to climate change signal (CCS) resulting from these two applications is limited. This study investigates QM impacts on the original temperature and precipitation CCSs when applied according to a bias correction only (BC-only) and a bias correction plus downscaling (BC + DS) application over reference stations in Central Italy. BC-only application is used to adjust regional climate model (RCM) simulations having the same resolution as the observation grid. QM BC + DS application adjusts the same simulations to point-wise observations. QM applications alter CCS mainly for temperature. BC-only application produces a CCS of the median ~ 1 °C lower than the original (~ 4.5 °C). BC + DS application produces CCS closer to the original, except over the summer 95th percentile, where substantial amplification of the original CCS resulted. The impacts of the two applications are connected to the ratio between the observed and the simulated standard deviation (STD) of the calibration period. For the precipitation, original CCS is essentially preserved in both applications. Yet, calibration period STD ratio cannot predict QM impact on the precipitation CCS when simulated STD and mean are similarly misrepresented.

ano.nymous@ccsd.cnrs.fr.invalid (Lorenzo Sangelantoni) 26 May 2020

https://hal.inrae.fr/hal-02623508v1

[hal-02624939] Using stable isotope approach to quantify pond dam impacts on isotopic niches and assimilation of resources by invertebrates in temporary streams: a case study

Fishponds built across streams can greatly affect their functioning, especially through loss of ecological continuity but also changes in water availability and trophic resources. Yet, their consequences on communities and stream functioning remain largely understudied. We investigated effects of fishpond dams on the trophic ecology of macroinvertebrate communities in temporary low-order streams using C and N stable isotopes. Food resources and macroinvertebrates were sampled in one upstream and one downstream site of two temporary streams, one stream without (reference stream) versus one with a fishpond (impacted stream) and used for isotopic analyses. Results suggested moderate effects of fishponds on the upstream tributaries. In contrast, at the downstream impacted site, ten times higher macroinvertebrate biomass and modifications in the trophic niches were recorded, likely due to changes in resource availability/quality and dam-related hydrology. By modifying the food sources as well as water fluxes, fishpond dams tend to alter macroinvertebrate communities but also shift the trophic dynamics downstream. This assessment stresses the need for exploring their impacts on food webs and nutrient fluxes at larger downstream distances to better understand their effects before drawing conclusions in regard to their management.

ano.nymous@ccsd.cnrs.fr.invalid (Brian Four) 16 Jun 2022

https://hal.inrae.fr/hal-02624939v1

[hal-02628795] Acclimation and adaptation components of the temperature dependence of plant photosynthesis at the global scale.

The temperature response of photosynthesis is one of the key factors determining predicted responses to warming in global vegetation models (GVMs). The response may vary geographically, owing to genetic adaptation to climate, and temporally, as a result of acclimation to changes in ambient temperature. Our goal was to develop a robust quantitative global model representing acclimation and adaptation of photosynthetic temperature responses. We quantified and modelled key mechanisms responsible for photosynthetic temperature acclimation and adaptation using a global dataset of photosynthetic CO2 response curves, including data from 141 C3 species from tropical rainforest to Arctic tundra. We separated temperature acclimation and adaptation processes by considering seasonal and common‐garden datasets, respectively. The observed global variation in the temperature optimum of photosynthesis was primarily explained by biochemical limitations to photosynthesis, rather than stomatal conductance or respiration. We found acclimation to growth temperature to be a stronger driver of this variation than adaptation to temperature at climate of origin. We developed a summary model to represent photosynthetic temperature responses and showed that it predicted the observed global variation in optimal temperatures with high accuracy. This novel algorithm should enable improved prediction of the function of global ecosystems in a warming climate.

ano.nymous@ccsd.cnrs.fr.invalid (Dushan P Kumarathunge) 27 May 2020

https://hal.inrae.fr/hal-02628795v1

[hal-02942682] Robust Response of Terrestrial Plants to Rising CO2

Human-caused CO 2 emissions over the past century have caused the climate of the Earth to warm and have directly impacted on the functioning of terrestrial plants. We examine the global response of terrestrial gross primary production (GPP) to the historic change in atmospheric CO 2. The GPP of the terrestrial biosphere has increased steadily, keeping pace remarkably in proportion to the rise in atmospheric CO 2. Water-use efficiency, namely the ratio of CO 2 uptake by photosynthesis to water loss by transpiration, has increased as a direct leaf-level effect of rising CO 2. This has allowed an increase in global leaf area, which has conspired with stimulation of photosynthesis per unit leaf area to produce a maximal response of the terrestrial biosphere to rising atmospheric CO 2 and contemporary climate change. Rising Atmospheric CO 2 and Global Climate Change Emissions of CO 2 associated with human industrial activity and land-use change over the past century have significantly impacted on global climate, causing global warming of about 1.0°C [1]. The anthropogenic CO 2 emission rate is continuing to increase, and the future rise in atmospheric CO 2 will undoubtedly lead to more climate change, including increases in the frequency of extreme climate events such as heatwaves, droughts, and storms [2]. Global climate change has the potential to significantly stress terrestrial vegetation [3], for example with hot, dry air, soil moisture deficits, or flooding. This could lead to a carbon-climate feedback in which widespread tree mortality and forest decline contribute to accelerating accumulation of CO 2 in the atmosphere [4-6]. On the other hand, plants interact directly with atmospheric CO 2 , and they can potentially respond to rising atmospheric CO 2 concentrations by increasing photosynthetic rates and water-use efficiency (see Glossary) [7-10]. Water-use efficiency in this context is defined as the amount of CO 2 taken up by photosynthesis for a given amount of water lost to the atmosphere by transpiration (Box 1). Understanding emergent responses of the production of terrestrial vegetation to the potentially opposing impacts of global climate change and CO 2 fertilization is crucial for formulating effective mitigation and adaptation strategies [11]. At a global scale, there is currently an imbalance between the amount of CO 2 absorbed by the terrestrial biosphere through photosynthesis and the amount released back to the atmosphere through plant respiration, decomposition, fire, and emissions from land-use change [12]. This is commonly referred to as the land carbon sink. It is slowing the rate of increase in atmospheric CO 2 that would otherwise result from anthropogenic CO 2 emissions. Predicting the future behaviour of the land carbon sink is one of the most important challenges in carbon cycle science, given the potential that feedbacks could accelerate the rate of future climate change [13]. This requires a thorough understanding of the process through which the terrestrial biosphere captures CO 2-photosynthesis. Highlights Global climate change caused by CO 2 emissions can stress terrestrial vegetation , potentially decreasing production. On the other hand, CO 2 interacts directly with plants, stimulating leaf-level photo-synthesis and water-use efficiency. The rise in atmospheric CO 2 concentration over the past century presents an opportunity for gauging the strength of the terrestrial biosphere response to these potential impacts. Atmospheric proxy and model analysis both suggest that global terrestrial photosynthesis has increased in nearly constant proportion to the rise in atmospheric CO 2 concentration, a maximal response by the terrestrial biosphere. An accurate understanding of the impacts of climate change on terrestrial vegetation is essential for managing risks associated with human-caused climate change: gauging the historic response of terrestrial photosynthesis is an important step in this direction.

ano.nymous@ccsd.cnrs.fr.invalid (Lucas A Cernusak) 18 Sep 2020

https://hal.inrae.fr/hal-02942682v1

[hal-02627690] From xylogenesis to tree rings: wood traits to investigate tree response to environmental changes

It is noteworthy that the largest part of global vegetation biomass depends on a thin layer of cells: the vascular cambium. Understanding the wood formation processes and relationships with environmental factors is a crucial and timely research question requiring interdisciplinary efforts, also to upscale the information gained and to evaluate implications for tree growth and forest productivity. We provide an overview of wood formation processes up to tree-ring development, bearing in mind that the combined action of intrinsic factors and environmental drivers determines the anatomical traits of a tree ring formed at a specific time and position within the tree’s architecture. After briefly reviewing intrinsic factors, we focus attention on environmental drivers highlighting how a correct interpretation of environmental signals in tree rings must be grounded in a deep knowledge of xylogenesis and consequent wood anatomical traits. We provide guidelines on novel methods and approaches recently developed to study xylem formation. We refer to existing literature on established techniques for retrospective analyses in tree-ring series of anatomical and isotopic traits, to assess long-term ecophysiological responses to environmental variations, also giving advice on possible bias because of interand within-tree variability. Finally, we highlight that, once the temporal axis of intra-annual tree-ring variability of xylem traits is established by xylogenesis analysis, a multidisciplinary approach linking classical dendro-ecology, wood functional traits (dendro-anatomy) and eco-physiology (here focusing on dendro-isotopes) allows a better interpretation of past environmental events hidden in tree rings, and more reliable forecasts of wood growth in response to climate change.

ano.nymous@ccsd.cnrs.fr.invalid (Veronica de Micco) 26 May 2020

https://hal.inrae.fr/hal-02627690v1

[hal-02903210] Habitats forestiers et forêts habitées

Les 26 et 27 mars 2019 se tenait, au sein du Domaine national de Chambord, un colloque international regroupant une centaine de participants originaires d’une dizaine de pays. Cet évènement scientifique venait conclure le projet de recherche interdisciplinaire COSTAUD « Contribution des ongulés sauvages au fonctionnement de l’écosystème et aux services rendus à Chambord », financé par la Région Centre-Val de Loire au titre de son Appel à Projets de Recherche d’Intérêt Régional (édition 2015). Intitulé Habitats forestiers et forêts habitées, il visait à questionner les interactions existant en forêt et ses habitats associés entre la faune et les usages, modes de gestion et pratiques sociales, en se structurant autour de quatre thèmes. Le thème 1 du colloque s’est intéressé aux facteurs environnementaux et humains à l’origine des populations animales actuelles Dans le thème 2, il s’agissait d’interroger l’influence de la faune, en l’occurrence des grands herbivores, sur le fonctionnement des écosystèmes. Le thème 3 a abordé les conséquences des modes de gestion des habitats forestiers, afin d’en identifier les impacts sur la faune, notamment sur sa distribution spatiale. Enfin le thème 4 s’est intéressé à la manière dont la faune pouvait être valorisée par la société, c’est-à-dire aux usages et pratiques sociales associés à la faune sauvage et aux milieux forestiers.

ano.nymous@ccsd.cnrs.fr.invalid (Christophe Baltzinger) 24 Nov 2021

https://hal.inrae.fr/hal-02903210v1

[hal-02964786] Le processus d'innovation technologique en sylviculture - Exemple des outils mécaniques de préparation du sol avant plantation

Un changement de pratiques sylvicoles s’impose pour assurer le renouvellement des forêts face aux changements globaux présents et à venir. C’est d’autant plus vrai avec la plantation qui doit subir des printemps au climat très contrasté. Assurer le transfert aux praticiens et propriétaires est essentiel pour garantir leur réussite.

ano.nymous@ccsd.cnrs.fr.invalid (Catherine Collet) 14 Oct 2020

https://hal.science/hal-02964786v1

[hal-02629182] Phenology of wood formation in larch (Larix decidua Mill.) trees growing along a 1000-m elevation gradient in the French Southern Alps

center dot Key message Spring temperature increase is the main driver of larch tree wood formation onset along a 1000-m elevation gradient in the Southern Alps, while its cessation is more probably controlled by water stress at the lowest elevation and photoperiod at higher ones. center dot Context The survival of perennial plants depends on their adaptation to changing environment and specially temperature, which in trees is notably implemented through wood formation process. center dot Aims Our main objective is to understand how the phenology of wood formation is related to environmental factors and to temperature in particular. center dot Methods We monitored the xylogenesis of 60 larch trees, distributed in four stands along an elevation gradient of 1000 m in the French Southern Alps. center dot Results Cambial activity started around mid-May at the lowest site (1350 m) and around mid-June at the highest one (2300 m), showing a delay of 5.4 days per degrees C. The onset of wall-thickening and mature phenophases followed the same linear trend with a delay of 5.2 and 3 days per degrees C, respectively. Phenophase cessations followed a parabolic trend with trees from the lowest site finishing their growth the first, while those from 1700 m finished the last. Our results show that the onset of xylem formation is mainly driven by spring temperature increase, while its cessation is more related to photoperiod, with water shortage being able to hasten it. center dot Conclusion Future climatic changes will most probably increase growing season length (but not necessarily wood production) and shift upwards the optimal elevation for larch growth in the Southern Alps.

ano.nymous@ccsd.cnrs.fr.invalid (Seyedeh Masoumeh Saderi) 27 May 2020

https://hal.inrae.fr/hal-02629182v1

[hal-02384205] Améliorer la capacité du chêne sessile à répondre à des sécheresses extrêmes : Réduction de la densité des peuplements. Étude dendro-écologique de réseaux d’expérimentations sylvicoles à long terme

Dans un contexte de changement climatique, les gestionnaires ont besoin de bases scientiﬁques pour adapter leurs itinéraires sylvicoles. Cela passe notamment par l’étude de l’inﬂuence de la compétition sur la réponse au climat et à ses variations.

ano.nymous@ccsd.cnrs.fr.invalid (Anna Schmitt) 28 Nov 2019

https://agroparistech.hal.science/hal-02384205v1

[hal-02624166] Assessing the scaling of the tree branch diameters frequency distribution with terrestrial laser scanning: methodological framework and issues

Key message This article presents a specific methodology for assessing the scaling of the frequency distribution of the branch diameters within a tree from terrestrial laser scanning (TLS), using large oak trees ( Quercus petraea (Matt.) Liebl.) as the case study. It emphasizes the potential of TLS in assessing branch scaling exponents and provides new insights in forest ecology and biomass allometric modelling. Context Many theoretical works invoke the scaling allometry of the frequency distribution of the branch diameters in tree form analyses, but testing such an allometry requires a huge amount of data that is particularly difficult to obtain from traditional measurements. Aims The aims of this study were (i) to clarify the theoretical and methodological basics of this allometry, (ii) to explore the possibility of establishing this allometry from terrestrial laser scanning (TLS) and geometric modelling for the solid wood structure (i.e. diameters > 7 cm) of large trees, and (iii) to highlight the major methodological issues. Methods Three large oak trees (Quercus petraea (Matt.) Liebl.) were digitized in leaf-off conditions from multiple points of view in order to produce accurate three-dimensional point clouds. Their woody structure was modelled using geometric procedures based on polyline and cylinder fitting. The allometry was established using basics found in literature: regular sampling of branch diameters and consideration of the living branches only. The impact of including the unpruned dead branches in the allometry was assessed, as well as the impact of modelling errors for the largest branch diameter classes. Results TLS and geometric modelling revealed a scaling exponent of − 2.4 for the frequency distribution of the branch diameters for the solid wood structure of the trees. The dead branches could highly influence the slope of the allometry, making essential their detection in TLS data. The accuracy of diameter measurement for the highest diameter classes required particular attention, slight errors in these classes having a high influence on the slope of the allometry. Conclusion These results could make it possible automated programs to process large numbers of trees and, therefore, to provide new insights in assessing forest structure, scaling, and dynamics for various environments in the context of climate change.

ano.nymous@ccsd.cnrs.fr.invalid (Mathieu Dassot) 26 May 2020

https://hal.inrae.fr/hal-02624166v1

[hal-03328388] Un outil en ligne pour accompagner le choix des essences forestières dans un contexte de changement climatique.

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ano.nymous@ccsd.cnrs.fr.invalid (Sophie Bertin) 30 Aug 2021

https://hal.science/hal-03328388v1

[hal-02622305] Diagnosis of forest soil sensitivity to harvesting residues removal – A transfer study of soil science knowledge to forestry practitioners

Forest biomass is a source of renewable energy that can contribute to meeting international targets for reducing greenhouse gas emissions. However, removing forest harvesting residues may cause important nutrient losses. Because negative effects of increased nutrient removal are not systematic, forest managers need tools for soil sensitivity assessment, to decide whether they can or not increase biomass harvesting without impairing long term forest productivity and health. This study follows two goals: (i) define forest ecosystem sensitivity indicators derived from soil physico-chemical analyses and (ii) build and test a simplified tool that predicts such soil sensitivity. After screening international literature, nutrient concentration in the topsoil was chosen as the simplest and currently most accurate indicator of soil sensitivity. With a consolidated database on French forest soils, we built diagnostic keys that predict soil sensitivity using only five parameters: humus form, topsoil texture, depth of CaCO3 apparition, ecological region, and rooting depth. We performed a statistical evaluation of the simplified tool on independent data sets and evaluated it in the field with potential users. As compared with the existing French forest soils sensitivity indicator, our diagnosis tool displayed lower high and low sensitivities classification errors and allowed to differentiate sensitivity into five elemental ones (Ca, Mg, K, P and N). All participating end users agreed with the necessity of such indicator and appreciated the simplicity of diagnosis with our tool. This study shows a complete research and development process, from the translation of scientific knowledge into an indicator of sustainable forest management to the simplification for assimilation.

ano.nymous@ccsd.cnrs.fr.invalid (Samuel Durante) 26 May 2020

https://hal.inrae.fr/hal-02622305v1

[hal-02311392] The functional trait spectrum of European temperate grasslands

Questions What is the functional trait variation of European temperate grasslands and how does this reflect global patterns of plant form and function? Do habitat specialists show trait differentiation across habitat types? Location Europe. Methods We compiled 18 regeneration and non-regeneration traits for a continental species pool consisting of 645 species frequent in five grassland types. These grassland types are widely distributed in Europe but differentiated by altitude, soil bedrock and traditional long-term management and disturbance regimes. We evaluated the multivariate trait space of this entire species pool and compared multi-trait variation and mean trait values of habitat specialists grouped by grassland type. Results The first dimension of the trait space accounted for 23% of variation and reflected a gradient between fast-growing and slow-growing plants. Plant height and SLA contributed to both the first and second ordination axes. Regeneration traits mainly contributed to the second and following dimensions to explain 56% of variation across the first five axes. Habitat specialists showed functional differences between grassland types mainly through non-regeneration traits. Conclusions The trait spectrum of plants dominating European temperate grasslands is primarily explained by growth strategies which are analogous to the trait variation observed at the global scale, and secondly by regeneration strategies. Functional differentiation of habitat specialists across grassland types is mainly related to environmental filtering linked with altitude and disturbance. This filtering pattern is mainly observed in non-regeneration traits, while most regeneration traits demonstrate multiple strategies within the same habitat type.

ano.nymous@ccsd.cnrs.fr.invalid (Emma Ladouceur) 26 May 2020

https://hal.science/hal-02311392v1

[hal-02346487] Precipitation mediates sap flux sensitivity to evaporative demand in the neotropics

Transpiration in humid tropical forests modulates the global water cycle and is a key driver of climate regulation. Yet, our understanding of how tropical trees regulate sap flux in response to climate variability remains elusive. With a progressively warming climate, atmospheric evaporative demand [i.e., vapor pressure deficit (VPD)] will be increasingly important for plant functioning, becoming the major control of plant water use in the twenty-first century. Using measurements in 34 tree species at seven sites across a precipitation gradient in the neotropics, we determined how the maximum sap flux velocity (vmax) and the VPD threshold at which vmax is reached (VPDmax) vary with precipitation regime [mean annual precipitation (MAP); seasonal drought intensity (PDRY)] and two functional traits related to foliar and wood economics spectra [leaf mass per area (LMA); wood specific gravity (WSG)]. We show that, even though vmax is highly variable within sites, it follows a negative trend in response to increasing MAP and PDRY across sites. LMA and WSG exerted little effect on vmax and VPDmax, suggesting that these widely used functional traits provide limited explanatory power of dynamic plant responses to environmental variation within hyper-diverse forests. This study demonstrates that long-term precipitation plays an important role in the sap flux response of humid tropical forests to VPD. Our findings suggest that under higher evaporative demand, trees growing in wetter environments in humid tropical regions may be subjected to reduced water exchange with the atmosphere relative to trees growing in drier climates.

ano.nymous@ccsd.cnrs.fr.invalid (Charlotte Grossiord) 17 Aug 2024

https://hal.umontpellier.fr/hal-02346487v1

[hal-03889618] Soil and climate differently impact NDVI patterns according to the season and the stand type

Several studies use satellite-based normalized difference vegetation index (NDVI) to monitor the impact of climate change on vegetation covers. Good understanding of the drivers of NDVI patterns is hindered by the difficulties in disentangling the effects of environmental factors from anthropogenic changes, by the limited number of environmental predictors studied, and by the diversity of responses according to periods and land covers. This study aims to improve our understanding of the different environmental drivers of NDVI spatial variations for different stand type characteristics of mountain and Mediterranean biomes. Using NDVI values extracted from MODIS Terra time series, we calculated Spring Greenness (SG) and annual Relative Greenness (RGRE) to depict spring and summer vegetation activity, respectively, in a contrasted area of 10,255 km2 located in the south of France. We modeled SG and RGRE at different scales, using 20 environmental predictors characterizing available energy, water supply, and nutrient supply calculated for different periods of the year. In spring, high minimum temperatures, good nitrogen availability, and acidic or neutral pH turned out to be determining for greenness, particularly for stand types located in altitude. In summer, an important soil water reserve and low temperatures promoted vegetation dynamics, particularly for stands located in areas with a Mediterranean climate. Our results show that NDVI dynamics was not only driven by climatic variability, and should not be studied using only mean temperature and rainfall. They highlight that different environmental factors act complementarily, and that soil parameters characterizing water stress and soil nutrition should be taken into account. While the factors limiting NDVI values varied according to the season and the position of the stands along the ecological gradients, we identified a global temperature and water-stress threshold when considering the whole vegetation.

ano.nymous@ccsd.cnrs.fr.invalid (Christian Piedallu) 08 Dec 2022

https://hal.science/hal-03889618v1

[hal-02147493] Climatic controls of decomposition drive the global biogeography of forest-tree symbioses

The identity of the dominant root-associated microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools sequester carbon and withstand the effects of climate change. Characterizing the global distribution of these symbioses and identifying the factors that control this distribution are thus integral to understanding the present and future functioning of forest ecosystems. Here we generate a spatially explicit global map of the symbiotic status of forests, using a database of over 1.1 million forest inventory plots that collectively contain over 28,000 tree species. Our analyses indicate that climate variables—in particular, climatically controlled variation in the rate of decomposition—are the primary drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal trees, which represent only 2% of all plant species7, constitute approximately 60% of tree stems on Earth. Ectomycorrhizal symbiosis dominates forests in which seasonally cold and dry climates inhibit decomposition, and is the predominant form of symbiosis at high latitudes and elevation. By contrast, arbuscular mycorrhizal trees dominate in aseasonal, warm tropical forests, and occur with ectomycorrhizal trees in temperate biomes in which seasonally warm-and-wet climates enhance decomposition. Continental transitions between forests dominated by ectomycorrhizal or arbuscular mycorrhizal trees occur relatively abruptly along climate-driven decomposition gradients; these transitions are probably caused by positive feedback effects between plants and microorganisms. Symbiotic nitrogen fixers—which are insensitive to climatic controls on decomposition (compared with mycorrhizal fungi)—are most abundant in arid biomes with alkaline soils and high maximum temperatures. The climatically driven global symbiosis gradient that we document provides a spatially explicit quantitative understanding of microbial symbioses at the global scale, and demonstrates the critical role of microbial mutualisms in shaping the distribution of plant species.

ano.nymous@ccsd.cnrs.fr.invalid (B. Steidinger) 04 Dec 2024

https://hal.science/hal-02147493v1

[hal-02264373] Additive effects of high growth rate and low transpiration rate drive differences in whole plant transpiration efficiency among black poplar genotypes

Poplar plantations, widely used for the production of woody biomass, might be at high risk from the climate change-induced increase in the frequency of drought periods. Therefore, selecting improved genotypes, which are highly productive but with a high water use efficiency (WUE), is becoming a major target. The use of automated weighing systems in controlled environments facilitates the estimation of cumulated water loss and whole plant transpiration efficiency (TE). Differences in TE and leaf level intrinsic WUE as well as the contribution of underlying ecophysiological traits were determined in three contrasting P. nigra genotypes. Strong differences in TE among the selected genotypes were congruent with differences in leaf level intrinsic WUE. Our data show that a high total leaf area was overcompensated by a low per leaf area transpiration rate, leading to higher TE in highly productive genotypes originating from cool locations. Nocturnal water loss was relatively low but contributed to variations in TE among genotypes. In response to drought, leaf level WUE increased but not TE, suggesting that carbon losses due to whole plant respiration could offset the drought-induced increase in intrinsic WUE.

ano.nymous@ccsd.cnrs.fr.invalid (Marie-Béatrice Bogeat-Triboulot) 06 Aug 2019

https://hal.science/hal-02264373v1

[hal-02052715] Compositional response of Amazon forests to climate change

Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate-induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long-term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water-deficit affiliation and wood density. Tree communities have become increasingly dominated by large-statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry-affiliated genera have become more abundant, while the mortality of wet-affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry-affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate-change drivers, but yet to significantly impact whole-community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large-statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.

ano.nymous@ccsd.cnrs.fr.invalid (Adriane Esquivel-Muelbert) 28 Feb 2019

https://hal.umontpellier.fr/hal-02052715v1

[hal-02149053] Water and nutrient uptake capacity of leaf-absorbing trichomes vs. roots in epiphytic tank bromeliads

The water and nutrient uptake mechanisms used by vascular epiphytes have been the subject of a few studies. While leaf absorbing trichomes (LATs) are the main organ involved in resource uptake by bromeliads, little attention has been paid to the absorbing role of epiphytic bromeliad roots. This study investigates the water and nutrient uptake capacity of LATs vs. roots in two epiphytic tank bromeliads Aechmea aquilega and Lutheria splendens. The tank and/or the roots of bromeliads were watered, or not watered at all, in different treatments. We show that LATs and roots have different functions in resource uptake in the two species, which we mainly attributed to dissimilarities in carbon acquisition and growth traits (e.g., photosynthesis, relative growth rate, non-structural carbohydrates, malate), to water relation traits (e.g., water and osmotic potential, relative water content, hydrenchyma thickness) and nutrient uptake (e.g., 15N-labelling). While the roots of A. aquilega did contribute to water and nutrient uptake, the roots of L. splendens were less important than the role played by the LATs in resource uptake. We also provide evidence for a synergistic effect of combined watering of tank and root in the Bromelioideae species. These results call for a more complex interpretation of LATs vs. roots in resource uptake in bromeliads.

ano.nymous@ccsd.cnrs.fr.invalid (Céline Leroy) 22 Oct 2021

https://hal.umontpellier.fr/hal-02149053v1

[hal-02628121] The multiscale routing model mRM v1.0: simple river routing at resolutions from 1 to 50 km

Routing streamflow through a river network is a fundamental requirement to verify lateral water fluxes simulated by hydrologic and land surface models. River routing is performed at diverse resolutions ranging from few kilometres to 1∘. The presented multiscale routing model mRM calculates streamflow at diverse spatial and temporal resolutions. mRM solves the kinematic wave equation using a finite difference scheme. An adaptive time stepping scheme fulfilling a numerical stability criterion is introduced in this study and compared against the original parameterisation of mRM that has been developed within the mesoscale hydrologic model (mHM). mRM requires a high-resolution river network, which is upscaled internally to the desired spatial resolution. The user can change the spatial resolution by simply changing a single number in the configuration file without any further adjustments of the input data. The performance of mRM is investigated on two datasets: a high-resolution German dataset and a slightly lower resolved European dataset. The adaptive time stepping scheme within mRM shows a remarkable scalability compared to its predecessor. Median Kling–Gupta efficiencies change less than 3 % when the model parameterisation is transferred from 3 to 48 km resolution. mRM also exhibits seamless scalability in time, providing similar results when forced with hourly and daily runoff. The streamflow calculated over the Danube catchment by the regional climate model REMO coupled to mRM reveals that the 50 km simulation shows a smaller bias with respect to observations than the simulation at 12 km resolution. The mRM source code is freely available and highly modular, facilitating easy internal coupling in existing Earth system models.

ano.nymous@ccsd.cnrs.fr.invalid (Stephan Thober) 27 May 2020

https://hal.inrae.fr/hal-02628121v1

[hal-02948737] Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests

There is mounting empirical evidence that lianas affect the carbon cycle of tropical forests. However, no single vegetation model takes into account this growth form, although such efforts could greatly improve the predictions of carbon dynamics in tropical forests. In this study, we incorporated a novel mechanistic representation of lianas in a dynamic global vegetation model (the Ecosystem Demography Model). We developed a liana-specific plant functional type and mechanisms representing liana-tree interactions (such as light competition, liana-specific allometries, and attachment to host trees) and parameterized them according to a comprehensive literature meta-analysis. We tested the model for an old-growth forest (Paracou, French Guiana) and a secondary forest (Gigante Peninsula, Panama). The resulting model simulations captured many features of the two forests characterized by different levels of liana infestation as revealed by a systematic comparison of the model outputs with empirical data, including local census data from forest inventories, eddy flux tower data, and terrestrial laser scanner-derived forest vertical structure. The inclusion of lianas in the simulations reduced the secondary forest net productivity by up to 0.46 t(C) ha(-1) year(-1), which corresponds to a limited relative reduction of 2.6% in comparison with a reference simulation without lianas. However, this resulted in significantly reduced accumulated above-ground biomass after 70 years of regrowth by up to 20 t(C)/ha (19% of the reference simulation). Ultimately, the simulated negative impact of lianas on the total biomass was almost completely cancelled out when the forest reached an old-growth successional stage. Our findings suggest that lianas negatively influence the forest potential carbon sink strength, especially for young, disturbed, liana-rich sites. In light of the critical role that lianas play in the profound changes currently experienced by tropical forests, this new model provides a robust numerical tool to forecast the impact of lianas on tropical forest carbon sinks.

ano.nymous@ccsd.cnrs.fr.invalid (Manfredo Porcia E Brugnera) 25 Sep 2020

https://hal.inrae.fr/hal-02948737v1

[hal-02624918] LiDAR-derived topography and forest structure predict fine-scale variation in daily surface temperatures in oak savanna and conifer forest landscapes

In mountain landscapes, surface temperatures vary over short distances due to interacting influences of topography and overstory vegetation on local energy and water balances. At two study landscapes in the Sierra Nevada of California, characterized by foothill oak savanna at 276–481 m elevation and montane conifer forest at 1977–2135 m, we deployed 288 near-surface (5 cm above the surface) temperature sensors to sample site-scale (30 m) temperature variation related to hillslope orientation and vegetation structure and microsite-scale (2–10 m) variation related to microtopography and tree overstory. Daily near-surface maximum and minimum temperatures for the 2013 calendar year were related to topographic factors and vegetation overstory characterized using small footprint LiDAR imagery acquired by the National Ecological Observatory Network (NEON) Airborne Observation Platform (AOP). At both landscapes we recorded large site and microsite spatial variation in daily maximum temperatures, and less absolute variation in daily minimum temperatures. Generalized boosted regression trees were estimated to measure the influence of tree canopy density, understory solar radiation, cold-air drainage and pooling, ground cover and microtopography on daily maximum and minimum temperatures at site and microsite scales. Site-scale models based on indices of understory solar radiation and landscape position explained an average of 61–65% of daily variation in maximum temperature; site-scale models based on tree canopy density and landscape position explained 65–83% of variation in minimum temperatures. Models explained <15% of variation in microsite-scale maximum temperatures but within-site heterogeneity was significantly correlated with within-site heterogeneity in modeled understory radiation at both landscapes. Tree canopy density and slope explained 33% of microsite-scale variation in minimum temperatures at savanna sites. Our results demonstrate that it is feasible to model site-scale variation in daily surface temperature extremes and within-site heterogeneity in surface temperatures using LiDAR-derived variables, supporting efforts to understand cross-scale relationships between surface microclimates and regional climate change. Improved understanding of topographic and vegetative buffering of thermal microclimates across mountain landscapes is key to projecting microclimate heterogeneity and potential species’ range dynamics under future climate change.

ano.nymous@ccsd.cnrs.fr.invalid (Frank W. Davis) 26 May 2020

https://hal.inrae.fr/hal-02624918v1

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Productions 2019

HAL : Dernières publications

[hal-02352504] The effect of tree diversity on the resistance and recovery of forest stands in the French Alps may depend on species differences in hydraulic features

[hal-02501278] Wood formation and tree adaptation to climate

[hal-02263853] Annotation data about multi criteria assessment methods used in the agri-food research: The French national institute for agricultural research (INRA) experience

[hal-02921264] Effects of organic inputs derived from pea and wheat root functional traits on soil protease activities

[hal-02154447] First evidences that the ectomycorrhizal fungus Paxillus involutus mobilizes nitrogen and carbon from saprotrophic fungus necromass

[hal-02165403] Infiltration from the Pedon to Global Grid Scales: An Overview and Outlook for Land Surface Modeling

[hal-02179547] Introduction to the invited issue on phloem function and dysfunction

[hal-02178452] Drought impacts on tree phloem

[hal-02178457] The impact of prolonged drought on phloem anatomy and phloem transport in young beech trees

[hal-02178455] Estimation of phloem carbon translocation belowground at stand level in a hinoki cypress stand

[hal-02628125] Are mixed-tree plantations including a nitrogen-fixing species more productive than monocultures?

[hal-02629130] Identifying the tree species compositions that maximize ecosystem functioning in European forests

[hal-02184243] Geographical adaptation prevails over species-specific determinism in trees' vulnerability to climate change at Mediterranean rear-edge forests

[hal-02625305] Chilling and forcing temperatures interact to predict the onset of wood formation in Northern Hemisphere conifers

[hal-02168619] Nondestructive and Fast Vibration Phenotyping of Plants

[hal-02622295] Massive postglacial gene flow between European white oaks uncovered genes underlying species barriers

[hal-02384139] Fructification du Hêtre et des Chênes en France : rôle des températures, du pollen et du bilan de carbone et relation avec la croissance des peuplements

[hal-02181076] Air temperature optima of vegetation productivity across global biomes.

[hal-02373054] Biomasse microbienne carbonée et activités enzymatiques : gammes de valeurs obtenues pour différents sols agricoles français et belges

[hal-02384184] Les réponses observées des arbres aux variations du climat (croissance, phénologie foliaire et fructification)

[hal-02411666] The commonness of rarity: Global and future distribution of rarity across land plants

[hal-02399726] The cost of deer to trees: changes in resource allocation from growth-related traits and phenolic content to structural defence

[hal-02320571] Quelle pertinence du modèle diversité-productivité-perturbations pour analyser l’influence des pratiques agricoles sur la diversité des prairies permanentes du Massif central ?

[hal-02432407] Large hydraulic safety margins protect Neotropical canopy rainforest tree species against hydraulic failure during drought

[hal-02011754] Explaining the larger seed bank of an invasive shrub in non-native versus native environments by differences in seed predation and plant size

[hal-02111822] Soils Drowned in Water Impoundments: A New Frontier

[hal-02118719] The influence of veneer thickness and knot proportion on the mechanical properties of laminated veneer lumber (LVL) made from secondary quality hardwood

[hal-02943204] Importance of Detoxification Processes in Ozone Risk Assessment: Need to Integrate the Cellular Compartmentation of Antioxidants?

[hal-02623508] Impact of bias correction and downscaling through quantile mapping on simulated climate change signal: a case study over Central Italy

[hal-02624939] Using stable isotope approach to quantify pond dam impacts on isotopic niches and assimilation of resources by invertebrates in temporary streams: a case study

[hal-02628795] Acclimation and adaptation components of the temperature dependence of plant photosynthesis at the global scale.

[hal-02942682] Robust Response of Terrestrial Plants to Rising CO2

[hal-02627690] From xylogenesis to tree rings: wood traits to investigate tree response to environmental changes

[hal-02903210] Habitats forestiers et forêts habitées

[hal-02964786] Le processus d'innovation technologique en sylviculture - Exemple des outils mécaniques de préparation du sol avant plantation

[hal-02629182] Phenology of wood formation in larch (Larix decidua Mill.) trees growing along a 1000-m elevation gradient in the French Southern Alps

[hal-02384205] Améliorer la capacité du chêne sessile à répondre à des sécheresses extrêmes : Réduction de la densité des peuplements. Étude dendro-écologique de réseaux d’expérimentations sylvicoles à long terme

[hal-02624166] Assessing the scaling of the tree branch diameters frequency distribution with terrestrial laser scanning: methodological framework and issues

[hal-03328388] Un outil en ligne pour accompagner le choix des essences forestières dans un contexte de changement climatique.

[hal-02622305] Diagnosis of forest soil sensitivity to harvesting residues removal – A transfer study of soil science knowledge to forestry practitioners

[hal-02311392] The functional trait spectrum of European temperate grasslands

[hal-02346487] Precipitation mediates sap flux sensitivity to evaporative demand in the neotropics

[hal-03889618] Soil and climate differently impact NDVI patterns according to the season and the stand type

[hal-02147493] Climatic controls of decomposition drive the global biogeography of forest-tree symbioses

[hal-02264373] Additive effects of high growth rate and low transpiration rate drive differences in whole plant transpiration efficiency among black poplar genotypes

[hal-02052715] Compositional response of Amazon forests to climate change

[hal-02149053] Water and nutrient uptake capacity of leaf-absorbing trichomes vs. roots in epiphytic tank bromeliads

[hal-02628121] The multiscale routing model mRM v1.0: simple river routing at resolutions from 1 to 50 km

[hal-02948737] Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests

[hal-02624918] LiDAR-derived topography and forest structure predict fine-scale variation in daily surface temperatures in oak savanna and conifer forest landscapes