2021 - UMR Silva

[hal-04528777] Improvement of modeling plant responses to low soil moisture in JULESvn4.9 and evaluation against flux tower measurements

Drought is predicted to increase in the future due to climate change, bringing with it myriad impacts on ecosystems. Plants respond to drier soils by reducing stomatal conductance in order to conserve water and avoid hydraulic damage. Despite the importance of plant drought responses for the global carbon cycle and local and regional climate feedbacks, land surface models are unable to capture observed plant responses to soil moisture stress. We assessed the impact of soil moisture stress on simulated gross primary productivity (GPP) and latent energy flux (LE) in the Joint UK Land Environment Simulator (JULES) vn4.9 on seasonal and annual timescales and evaluated 10 different representations of soil moisture stress in the model. For the default configuration, GPP was more realistic in temperate biome sites than in the tropics or high-latitude (cold-region) sites, while LE was best simulated in temperate and high-latitude (cold) sites. Errors that were not due to soil moisture stress, possibly linked to phenology, contributed to model biases for GPP in tropical savanna and deciduous forest sites. We found that three alternative approaches to calculating soil moisture stress produced more realistic results than the default parameterization for most biomes and climates. All of these involved increasing the number of soil layers from 4 to 14 and the soil depth from 3.0 to 10.8 m. In addition, we found improvements when soil matric potential replaced volumetric water content in the stress equation (the "soill4_psi" experiments), when the critical threshold value for inducing soil moisture stress was reduced ("soil14_p0"), and when plants were able to access soil moisture in deeper soil layers ("soil14_dr*2"). For LE, the biases were highest in the default configuration in temperate mixed forests, with overestimation occurring during most of the year. At these sites, reducing soil moisture stress (with the new parameterizations mentioned above) increased LE and increased model biases but improved the simulated seasonal cycle and brought the monthly variance closer to the measured variance of LE. Further evaluation of the reason for the high bias in LE at many of the sites would enable improvements in both carbon and energy fluxes with new parameterizations for soil moisture stress. Increasing the soil depth and plant access to deep soil moisture improved many aspects of the simulations, and we recommend these settings in future work using JULES or as a general way to improve land surface carbon and water fluxes in other models. In addition, using soil matric potential presents the opportunity to include plant functional type-specific parameters to further improve modeled fluxes.

ano.nymous@ccsd.cnrs.fr.invalid (Anna B Harper) 02 Apr 2024

https://hal.inrae.fr/hal-04528777v1

[hal-03483916] Phenotypic and genotypic data of a European beech (Fagus sylvatica L.) progeny trial issued from three plots along an elevation gradient in Mont Ventoux, South-Eastern France

Key Message: We provide phenotypic and genotypic data for a progeny trial of 5813 European beech seedlings, originating from 60 open-pollinated families collected at three altitudes (1020 m; 1140 m, 1340 m) on Mont Ventoux (44° 11′ N; 17° 5′ E). Background: Considering the patterns of adaptive traits’ genetic divergence and local adaptation displayed by many tree species at large spatial scale, forest tree populations are usually assumed to have a high evolutionary potential (Alberto et al. 2013). However, there is still limited evidence of the level of genetic variation available within population at key functional traits involved in response to climate. Moreover, we also need to investigate the abilities of tree populations to adapt to local variation of their environment (i.e., microgeographic adaptation, Richardson et al. 2014). Abstract: This data paper extensively describes a valuable quantitative genetic experiment designed to address these issues in the European beech (Fagus sylvatica L.), a major tree species in Europe. Sixty beech maternal progenies were collected in three plots along an elevation gradient and grown in a common garden under two contrasted experimental conditions (water stress/no water stress), to assess how the variation at twelve adaptive traits partitioned within and among families, plots, and experimental contrasts. Moreover, we genotyped a subset of offspring and all the potentially reproductive adults in the three plots at 13 microsatellite markers to infer paternal relationships and to estimate average relatedness within and between maternal families and genetic divergence among plots.

ano.nymous@ccsd.cnrs.fr.invalid (Sylvie Oddou-Muratorio) 16 Dec 2021

https://hal.inrae.fr/hal-03483916v1

[hal-03123656] OSIP1 is a self‐assembling DUF3129 protein required to protect fungal cells from toxins and stressors

Secreted proteins are key players in fungal physiology and cell protection against external stressing agents and antifungals. Oak stress-induced protein 1 (OSIP1) is a fungal-specific protein with unknown function. By using Podospora anserina and Phanerochaete chrysosporium as models, we combined both in vivo functional approaches and biophysical characterization of OSIP1 recombinant protein. The P. anserina OSIP1(Delta) mutant showed an increased sensitivity to the antifungal caspofungin compared to the wild type. This correlated with the production of a weakened extracellular exopolysaccharide/protein matrix (ECM). Since the recombinant OSIP1 from P. chrysosporium self-assembled as fibers and was capable of gelation, it is likely that OSIP1 is linked to ECM formation that acts as a physical barrier preventing drug toxicity. Moreover, compared to the wild type, the OSIP1(Delta) mutant was more sensitive to oak extractives including chaotropic phenols and benzenes. It exhibited a strongly modified secretome pattern and an increased production of proteins associated to the cell-wall integrity signalling pathway, when grown on oak sawdust. This demonstrates that OSIP1 has also an important role in fungal resistance to extractive-induced stress.

ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Valette) 25 Mar 2021

https://hal.science/hal-03123656v1

[hal-03293479] The climatic debt is growing in the understorey of temperate forests: Stand characteristics matter

Aim. Climate warming reshuffles biological assemblages towards less cold-adapted but more warm-adapted species, a process coined thermophilization. However, the velocity at which this process is happening generally lags behind the velocity of climate change, generating a climatic debt the temporal dynamics of which remain misunderstood. Relying on high-resolution time series of vegetation data from a long-term monitoring network of permanent forest plots, we aim at quantifying the temporal dynamics – up to a yearly resolution – of the climatic debt in the understorey of temperate forests before identifying the key determinants that modulate it. Location. France. Time period. 1995–2017. Taxa studied. Vascular plants. Methods. We used the community temperature index (CTI) to produce a time series of understorey plant community thermophilization, which we subsequently compared to a time series of mean annual temperature changes over the same period and for the same sites. The direction and magnitude of the difference (i.e., the climatic debt) was finally analysed using linear mixed-effect models to assess the relative contributions of abiotic and biotic determinants, including forest stand characteristics. Results. We found a significant increase in CTI values over time (0.08–0.09 °C/decade), whereas the velocity of mean annual temperature changes was three times higher over the same period (0.22–0.28 °C/decade). Hence, the climatic debt increased over time and was greater in forest stands with higher basal area or older trees as well as under warmer macroclimate. By contrast, a greater frequency of anthropogenic disturbances decreased the climatic debt, while natural disturbances and herbivory had no impact. Conclusions. Although often overlooked in understanding the climatic debt of forest biodiversity, changes in forest stand characteristics may modulate the climatic debt by locally modifying microclimatic conditions. Notably, the buffering effect of the upper canopy layer implies microclimate dynamics that may provide more time for understorey plant communities to locally adapt.

ano.nymous@ccsd.cnrs.fr.invalid (Benoit Richard) 21 Jul 2021

https://hal.science/hal-03293479v1

[hal-03282821] The GenTree Platform: growth traits and tree-level environmental data in 12 European forest tree species

Progress in the field of evolutionary forest ecology has been hampered by the huge challenge of phenotyping trees across their ranges in their natural environments, and the limitation in high-resolution environmental information;The GenTree Platform contains phenotypic and environmental data from 4,959 trees from 12 ecologically and economically important European forest tree species: Abies alba Mill. (silver fir), Betula pendula Roth. (silver birch), Fagus sylvatica L. (European beech), Picea abies (L.) H. Karst (Norway spruce), Pinus cembra L. (Swiss stone pine), Pinus halepensis Mill. (Aleppo pine), Pinus nigra Arnold (European black pine), Pinus pinaster Aiton (maritime pine), Pinus sylvestris L. (Scots pine), Populus nigra L. (European black poplar), Taxus baccata L. (English yew), and Quercus petraea (Matt.) Liebl. (sessile oak). Phenotypic (height, diameter at breast height, crown size, bark thickness, biomass, straightness, forking, branch angle, fructification), regeneration, environmental in situ measurements (soil depth, vegetation cover, competition indices), and environmental modeling data extracted by using bilinear interpolation accounting for surrounding conditions of each tree (precipitation, temperature, insolation, drought indices) were obtained from trees in 194 sites covering the species’ geographic ranges and reflecting local environmental gradients. The GenTree Platform is a new resource for investigating ecological and evolutionary processes in forest trees. The coherent phenotyping and environmental characterization across 12 species in their European ranges allow for a wide range of analyses from forest ecologists, conservationists, and macro-ecologists. Also, the data here presented can be linked to the GenTree Dendroecological collection, the GenTree Leaf Trait collection, and the GenTree Genomic collection presented elsewhere, which together build the largest evolutionary forest ecology data collection available.

ano.nymous@ccsd.cnrs.fr.invalid (Lars Opgenoorth) 17 Nov 2021

https://hal.inrae.fr/hal-03282821v1

[hal-03167847] Recent increase in European forest harvests as based on area estimates (Ceccherini et al. 2020a) not confirmed in the French case

A recent paper by Ceccherini et al. (2020a) reported an abrupt increase of 30% in the French harvested forest area in 2016–2018 compared to 2004–2015. A re-analysis of their data rather led us to conclude that, when accounting for the singular effect of storm Klaus, the rate of change in harvested area depended on the change year used to separate the two periods to compare. Moreover, the comparison with data on harvested volumes from different sources brought contrasted results depending on the source. Therefore, it cannot be concluded that wood harvest increased in France in 2016–2018 compared to 2004–2015. The discrepancy between Ceccherini et al.’s data and other data on harvested volumes points out the difficulty of reconciling different approaches to estimate wood harvest at a country level.

ano.nymous@ccsd.cnrs.fr.invalid (Nicolas Picard) 01 Dec 2022

https://hal.inrae.fr/hal-03167847v1

[hal-03423711] Quels besoins de connaissances pour le futur des forêts en France ? Au-delà du plan de relance

Le plan France Relance lancé en septembre 2020 prévoit des mesures forestières sur 2 ans, avec un accent sur la reconstitution des peuplements forestiers sinistrés, affaiblis par les sécheresses ou attaqués par les scolytes. Cependant la crise forestière liée au changement climatique est partie pour durer et les efforts sur les connaissances à acquérir pour aider la forêt à s’adapter au changement climatique devront être poursuivis sur le long terme. Nous identifions quatre enjeux principaux, fortement liés à la préservation de la biodiversité : 1) S’assurer des conditions de succès d’établissement des forêts plantées. 2) Tirer parti des dynamiques naturelles et de la biodiversité pour limiter les risques. 3) Raisonner territorialement, impliquer davantage les acteurs. 4) Connecter les enjeux nationaux aux enjeux économiques mondiaux.

ano.nymous@ccsd.cnrs.fr.invalid (Maya Leroy) 10 Nov 2021

https://hal.inrae.fr/hal-03423711v1

[hal-03363005] Climate and socio-economic factors explain differences between observed and expected naturalization patterns of European plants around the world

Aim The number of naturalized (i.e. established) alien species has increased rapidly over recent centuries. Given the differences in environmental tolerances among species, little is known about what factors determine the extent to which the observed size of the naturalized range of a species and hence the extent to which the observed richness of naturalized species of a region approach their full potential. Here, we asked which region- and species-specific characteristics explain differences between observed and expected naturalizations. Location Global. Time period Present. Major taxa studied Vascular plants. Methods We determined the observed naturalized distribution outside Europe for 1,485 species endemic to Europe using the Global Naturalized Alien Flora (GloNAF) database and their expected distributions outside Europe using species distribution models. First, we investigated which of seven socio-economic factors related to introduction pathways, anthropogenic pressures and inventory effort best explained the differences between observed and expected naturalized European floras. Second, we examined whether distributional features, economic use and functional traits explain the extent to which species have filled their expected ranges outside Europe. Results In terms of suitable area, more than 95% of expected naturalizations of European plants were not yet observed. Species were naturalized in only 4.2% of their suitable regions outside of Europe (range filling) and in 0.4% of their unsuitable regions (range expansion). Anthropogenic habitat disturbance primarily explained the difference between observed and expected naturalized European floras, as did the number of treaties relevant to invasive species. Species of ornamental and economic value and with large specific leaf area performed better at filling and expanding beyond their expected range. Main conclusions The naturalization of alien plant species is explained by climate matching but also by the regional level of human development, the introduction pressure associated with the ornamental and economic values of the species and their adaptation to disturbed environments.

ano.nymous@ccsd.cnrs.fr.invalid (Robin Pouteau) 02 Oct 2021

https://hal.umontpellier.fr/hal-03363005v1

[hal-03466115] A generic information framework for decision-making in a forest-based bio-economy

Key message We present a methodological framework that both scientists and supply chain actors can mobilise to organise information at different scales of observation, and further make informed decisions regarding the supply and extraction of bio-molecules from forest biomass. We demonstrate its usefulness for extracting bio-molecules contained in silver fir growing in France. Context Numerous bio-active molecules can be extracted from trees at an industrial scale. Supply chain actors play a central role in this emerging bio-economy. However, they do not have enough information and tools to make informed decisions with respect to species, growing locations, or identities of potential suppliers of relevant wood biomass. Aims We explore and demonstrate an information chain and methodological framework that can help make three critical decisions regarding the selection of (1) the species containing the desired bio-molecules, (2) the locations where the resource is collected, and (3) the supply chain partners and types of industrial wood by-products necessary to obtain sufficient biomass for industrial extraction. Methods The methodological framework provides detailed guidelines and references to select the right combination of sampling protocol, allometric models, chemical analyses, GIS tools, and forest growth and supply chain models in order to produce information for the three decision steps within various regional contexts. Results We apply the framework within the context of supply chain actors who are interested in estimating the quantity and diversity of bio-molecules contained in silver fir (Abies alba Mill.) growing in the Grand Est region of France. We show how conflicting environmental, legal and economic constraints can affect the results. We discuss future challenges that need to be tackled to improve the methodological framework. Conclusion This study represents a highly detailed overview of the potential bio-molecules contained in a tree species, from its natural habitat or plantation to the end of the regional supply chain. It also represents a step towards the development of a generic knowledge infrastructure and methodology that is necessary to solve various decision-making problems regarding the industrial supply and extraction of high-value bio-molecules.

ano.nymous@ccsd.cnrs.fr.invalid (Jean-Baptiste Pichancourt) 28 Sep 2022

https://hal.inrae.fr/hal-03466115v1

[hal-02930429] Genomic and phenotypic divergence unveil microgeographic adaptation in the Amazonian hyperdominant tree Eperua falcata Aubl. (Fabaceae)

Plant populations can undergo very localized adaptation, allowing widely distributed populations to adapt to divergent habitats in spite of recurrent gene flow. Neotropical trees –whose large and undisturbed populations often span a variety of environmental conditions and local habitats – are particularly good models to study this process. Here, we explore patterns of adaptive divergence from large (i.e. regional) to small (i.e. microgeographic) spatial scales in the hyperdominant Amazonian tree Eperua falcata Aubl. (Fabaceae) under a replicated design involving two microhabitats (~300 m apart) in two study sites (~300 km apart). A three-year reciprocal transplant illustrates that, beyond strong maternal effects and phenotypic plasticity, genetically driven divergence in seedling growth and leaf traits was detected both between seedlings originating from different regions, and between seedlings from different microhabitats. In parallel, a complementary genome scan for selection was carried out through whole-genome sequencing of tree population pools. A set of 290 divergence outlier SNPs was detected at the regional scale (between study sites), while 185 SNPs located in the vicinity of 106 protein-coding genes were detected as replicated outliers between microhabitats within regions. Outlier-surrounding genomic regions are involved in a variety of physiological processes, including plant responses to stress (e.g., oxidative stress, hypoxia and metal toxicity) and biotic interactions. Together with evidence of microgeographic divergence in functional traits, the discovery of genomic candidates for microgeographic adaptive divergence represents a promising advance in our understanding of local adaptation, which likely operates across multiple spatial scales and underpins divergence and diversification in Neotropical trees.

ano.nymous@ccsd.cnrs.fr.invalid (Louise Brousseau) 25 Oct 2023

https://hal.inrae.fr/hal-02930429v1

[hal-03516967] Retrieval and validation of forest background reflectivity from daily Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) data across European forests

Information about forest background reflectance is needed for accurate biophysical parameter retrieval from forest canopies (overstory) with remote sensing. Separating under- and overstory signals would enable more accurate modeling of forest carbon and energy fluxes. We retrieved values of the normalized difference vegetation index (NDVI) of the forest understory with the multi-angular Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo data (gridded 500 m daily Collection 6 product), using a method originally developed for boreal forests. The forest floor background reflectance estimates from the MODIS data were compared with in situ understory reflectance measurements carried out at an extensive set of forest ecosystem experimental sites across Europe. The reflectance estimates from MODIS data were, hence, tested across diverse forest conditions and phenological phases during the growing season to examine their applicability for ecosystems other than boreal forests. Here we report that the method can deliver good retrievals, especially over different forest types with open canopies (low foliage cover). The performance of the method was found to be limited over forests with closed canopies (high foliage cover), where the signal from understory becomes too attenuated. The spatial heterogeneity of individual field sites and the limitations and documented quality of the MODIS BRDF product are shown to be important for the correct assessment and validation of the retrievals obtained with remote sensing.

ano.nymous@ccsd.cnrs.fr.invalid (Jan Pisek) 07 Jan 2022

https://hal.inrae.fr/hal-03516967v1

[hal-03278925] Method comparison of indirect assessments of understory leaf area index (LAIu): A case study across the extended network of ICOS forest ecosystem sites in Europe

Leaf area index (LAI) is a key ecological indicator for describing the structure of canopies and for modelling energy exchange between atmosphere and biosphere. While LAI of the forest overstory can be accurately assessed over large spatial scales via remote sensing, LAI of the forest understory (LAIu) is still largely ignored in ecological studies and ecosystem modelling due to the fact that it is often too complex to be destructively sampled or approximated by other site parameters. Additionally, so far only few attempts have been made to retrieve understory LAI via remote sensing, because dense canopies with high LAI are often hindering retrieval algorithms to produce meaningful estimates for understory LAI. Consequently, the forest understory still constitutes a poorly investigated research realm impeding ecological studies to properly account for its contribution to the energy absorption capacity of forest stands. This study aims to compare three conceptually different indirect retrieval methodologies for LAIu over a diverse panel of forest understory types distributed across Europe. For this we carried out near-to-surface measurements of understory reflectance spectra as well as digital surface photography over the extended network of Integrated Carbon Observation System (ICOS) forest ecosystem sites. LAIu was assessed by exploiting the empirical relationship between vegetation cover and light absorption (Beer-Lambert- Bouguer law) as well as by utilizing proposed relationships with two prominent vegetation indices: normalized difference vegetation index (NDVI) and simple ratio (SR). Retrievals from the three methods were significantly correlated with each other (r = 0.63–0.99, RMSE = 0.53–0.72), but exhibited also significant bias depending on the LAI scale. The NDVI based retrieval approach most likely overestimates LAI at productive sites when LAIu > 2, while the simple ratio algorithm overestimates LAIu at sites with sparse understory vegetation and presence of litter or bare soil. The purely empirical method based on the Beer-Lambert law of light absorption seems to offer a good compromise, since it provides reasonable LAIu values at both low and higher LAI ranges. Surprisingly, LAIu variation among sites seems to be largely decoupled from differences in climate and light permeability of the overstory, but significantly increased with vegetation diversity (expressed as species richness) and hence proposes new applications of LAIu in ecological modelling.

ano.nymous@ccsd.cnrs.fr.invalid (Jan-Peter George) 06 Jul 2021

https://hal.inrae.fr/hal-03278925v1

[hal-03134066] C-STABILITY an innovative modeling framework to leverage the continuous representation of organic matter

The understanding of soil organic matter (SOM) dynamics has considerably advanced in recent years. It was previously assumed that most SOM consisted of recalcitrant compounds, whereas the emerging view considers SOM as a range of polymers continuously processed into smaller molecules by decomposer enzymes. Mainstreaming this new paradigm in current models is challenging because of their ill-adapted framework. We propose the C-STABILITY model to resolve this issue. Its innovative framework combines compartmental and continuous modeling approaches to accurately reproduce SOM cycling processes. C-STABILITY emphasizes the influence of substrate accessibility on SOM turnover and makes enzymatic and microbial biotransformations of substrate explicit. Theoretical simulations provide new insights on how depolymerization and decomposers ecology impact organic matter chemistry and amount during decomposition and at steady state. The flexible mathematical structure of C-STABILITY offers a promising foundation for exploring new mechanistic hypotheses and supporting the design of future experiments.

ano.nymous@ccsd.cnrs.fr.invalid (Julien Sainte-Marie) 08 Feb 2021

https://agroparistech.hal.science/hal-03134066v1

[hal-03037249] Mixing has limited impacts on the foliar nutrition of European beech and Scots pine trees across Europe

Tree species-mixing has been suggested as one option to counteract the adverse effects of global change on tree mineral nutrition, yet the effect of mixing on nutrient availability remains poorly documented.We therefore analyzed the current foliar nutrient (N, P, K, Ca, Mg) quantities and ilr balances (isometric log transformed ratios between elements or groups of elements) for 261 European beech and 248 Scots pine trees from 15 sites, each consisting of one beech-pine mixed stand and the respective monocultures, across a gradient of environmental conditions in Europe. We hypothesized an overall positive effect of mixing on tree foliar nutrient content, and that this mixing effect would be stronger on nutrient-poor sites. Using linear mixed models and multivariate linear regression models, we first tested for the effects of species (beech/pine) and composition (pure/mixed) across all sites; we then investigated whether the species-mixing effect was related to site fertility.The nutrient composition of beech leaves and pine needles differed significantly for all ilr balances. For both species, significant mixing effects were detected for some nutrients and ilr balances; those effects, however, could not be consistently related to contrasted nutrient composition between species. For most nutrients and ilr balances, the mixing effect was influenced by the site nutritional status, but the pattern differed from expectation: absence or minor differences between monocultures and mixtures at the lower end of the chemical fertility gradient, and maximum differences in rich soils.The contrasting foliar nutrient composition of pine and beech trees and the site nutrient status only partly explained the mixing effects on tree mineral nutrition. Our results claim for a better understanding of nutrientrelated mechanisms associated with complementarity and points towards the need to further expand the existing frameworks to account for the multivariate nature of tree nutrition.

ano.nymous@ccsd.cnrs.fr.invalid (Géraud de Streel) 06 Jan 2025

https://hal.inrae.fr/hal-03037249v1

[hal-03334205] Numerical classification of the Carici caryophylleae-Genistetea lobelii in Corsica (France)

The class ‘Carici caryophylleae-Genistetea lobelii Klein 1972’ corresponds to Cyrno-Sardian oromediterranean cushion-scrubs and related grasslands. In France, this class is only present in Corsica and the syntaxonomic scheme is debated among phytosociologists. This paper aims to highlight the main plant associations of the Carici caryophylleae-Genistetea lobelii Klein 1972 and to define the diagnostic species for each phytosociological unit. Diagnostic species are defined as species with a distinct concentration of occurrence or abundance in a particular vegetation unit. We compiled 519 vegetation plots and we applied the EuroVegChecklist expert system for the classes of European vegetation to only retain vegetation plots belonging to the Carici caryophylleae-Genistetea lobelii. We obtained a dataset with 189 vegetation plots, and we classified them using the Modified TWINSPAN classification. Our analyses identified six plant associations and three sub-associations that have already been described in the literature; and we were able to describe a new alliance corresponding to supramediterranean plant communities (Genistion salzmannii). For each of them, we identified diagnostic, constant, and dominant species and produced their distribution map. Formal definitions were then written for each phytosociological unit (from sub-association to class) and grouped in an expert system to classify the plant communities of the Carici caryophylleae-Genistetea lobelii.

ano.nymous@ccsd.cnrs.fr.invalid (P. Delbosc) 27 Jan 2023

https://hal.science/hal-03334205v1

[hal-03889520] Climate change impact on tree mortality differs with tree social status

Changes in temperature and rainfall linked to recent climate change increase the mortality rates of European temperate tree species. The economic importance of trees and the ecosystem services they provide differ according to their social status (dominant or suppressed trees) and their size. The extent to which climate change impacts these different categories in different ways remains little explored. Ecophysiological differences between tree size and status suggest different sensitivities to climate change. Dominant trees are exposed to more evapotranspiration than suppressed trees that benefit from buffered climatic conditions. Large trees are able to develop a network of fine roots that allow deeper water and nutrient uptake during water shortage periods, but that have higher water requirements and more physical constraints than small trees due to the fact that they must lift water to greater heights. We used 207,100 trees from the French forest inventory data (including 3,514 dead trees), representing eight common European tree species. For each species, we separated the tree population into three subsets of suppressed, small dominant and large dominant trees. For each subset, we modelled the mortality observed in a stand in the absence of disturbances (background mortality), with a focus on the differences in sensitivity to recent changes in temperature and rainfall. After having taken the main mortality drivers related to competition into account, as well as stand characteristics including logging intensity effect, we assessed the over-mortality linked to the recent changes in temperature and rainfall for each of the three subsets. When considering both changes in temperature and rainfall, the climate change related to over-mortality was greater for suppressed than for small or large dominant trees, for all the species. Over-mortality of suppressed trees was related to temperature increase, whereas a maximum vulnerability related to rainfall decrease was observed for large dominant trees. Over-mortality driven by climate change not only concerns large and dominant trees, but small and especially suppressed ones as well. These results suggest that in addition to wood production, forest renewal and ecosystem services associated with understorey vegetation are threatened by the recent changes in temperature and rainfall in European temperate forests.

ano.nymous@ccsd.cnrs.fr.invalid (Adrien Taccoen) 24 Jan 2024

https://hal.science/hal-03889520v2

[hal-04226966] Drought elicits contrasting responses on the autumn dynamics of wood formation in late successional deciduous tree species

Abstract Research on wood phenology has mainly focused on reactivation of the cambium in spring. In this study we investigated if summer drought advances cessation of wood formation and if it has any influence on wood structure in late successional forest trees of the temperate zone. The end of xylogenesis was monitored between August and November in stands of European beech and pedunculate oak in Belgium for two consecutive years, 2017 and 2018, with the latter year having experienced an exceptional summer drought. Wood formation in oak was affected by the drought, with oak trees ceasing cambial activity and wood maturation about 3 weeks earlier in 2018 compared with 2017. Beech ceased wood formation before oak, but its wood phenology did not differ between years. Furthermore, between the 2 years, no significant difference was found in ring width, percentage of mature fibers in the late season, vessel size and density. In 2018, beech did show thinner fiber walls, whereas oak showed thicker walls. In this paper, we showed that summer drought can have an important impact on late season wood phenology xylem development. This will help to better understand forest ecosystems and improve forest models.

ano.nymous@ccsd.cnrs.fr.invalid (Inge Dox) 03 Oct 2023

https://hal.inrae.fr/hal-04226966v1

[hal-03265612] Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient

A valid representation of intra-annual wood formation processes in global vegetation models is vital for assessing climate change impacts on the forest carbon stock. Yet, wood formation is generally modelled with photosynthesis, despite mounting evidence that cambial activity is rather directly constrained by limiting environmental factors. Here, we apply a state-of-the-art turgor-driven growth model to simulate 4 yr of hourly stem radial increment fromPicea abies(L.) Karst. andLarix deciduaMill. growing along an elevational gradient. For the first time, wood formation observations were used to validate weekly to annual stem radial increment simulations, while environmental measurements were used to assess the climatic constraints on turgor-driven growth. Model simulations matched the observed timing and dynamics of wood formation. Using the detailed model outputs, we identified a strict environmental regulation on stem growth (air temperature > 2 degrees C and soil water potential > -0.6 MPa). Warmer and drier summers reduced the growth rate as a result of turgor limitation despite warmer temperatures being favourable for cambial activity. These findings suggest that turgor is a central driver of the forest carbon sink and should be considered in next-generation vegetation models, particularly in the context of global warming and increasing frequency of droughts.

ano.nymous@ccsd.cnrs.fr.invalid (Richard L Peters) 17 Jan 2025

https://hal.inrae.fr/hal-03265612v1

[hal-04226953] SabaTracheid 1.0: A Novel Program for Quantitative Analysis of Conifer Wood Anatomy — A Demonstration on African Juniper From the Blue Nile Basin

Knowledge about past climates, especially at a seasonal time scale, is important as it allows informed decisions to be made to mitigate future climate change. However, globally, and especially in semi-arid Tropics, instrumental climatic data are scarce. A dendroclimatic approach may fill this gap, but tropical dendrochronological data are rare and do not yet provide fine resolution intra-annual information about past climates. Unlike in the Tropics, in the Mediterranean, temperate, alpine, and arctic regions, dendroanatomy and quantitative wood anatomy (QWA) are progressing fast attaining an intra-annual resolution, which allows a better understanding of seasonal climate dynamics and climate–growth relationships. The existing dendroanatomical and QWA methods aren’t suitable for tropical trees because they do not consider the high variation in tree ring width and the frequent occurrence of micro-rings containing only a few tracheids per radial file. The available tracheid analysis programs generally fail to provide multiple sectors for micro-rings and they are unable to compute most of the useful dendroanatomical parameters at fine temporal resolutions. Here, we present a program (SabaTracheid) that addresses the three main standard tasks that are necessary for QWA and dendroanatomy before running a climate analysis: (1) tracheidogram standardization, (2) sectoring, and (3) computing QWA and dendroanatomical variables. SabaTracheid is demonstrated on African Juniper ( Juniperus procera Hochst. ex Endl), but it is potentially able to provide fine-resolution QWA and dendroanatomic data that could be used for dendroanatomical studies in all regions of the world. SabaTracheid is a freeware that quickly and accurately standardizes tracheidograms, divides tree rings into multiple regular sectors, computes useful dendroanatomic and QWA variables for the whole tree rings, early- and latewood portions, and each sector separately. This program is particularly adapted to deal with high inter-annual growth variations observed in tropical trees so that it assures the provision of complete sectoral QWA and dendroanatomical data for micro-rings as well. We demonstrate SabaTracheid using a dataset of 30 Juniperus procera tree rings from the Blue Nile basin, in Ethiopia. SabaTracheid ’s ability to provide fine resolution QWA and dendroanatomic data will help the discipline develop in tropical as well as in the Mediterranean and temperate regions.

ano.nymous@ccsd.cnrs.fr.invalid (Eyob Gebrehiwot Gebregeorgis) 03 Oct 2023

https://hal.inrae.fr/hal-04226953v1

[hal-03351338] Improving the Fagacées growth model with an expanded common beech (Fagus sylvatica L.) data series from France and Germany

Key message: The Fagacées growth model was originally designed for application in the Northern half of France. It is a robust model with potential applicability to a larger area, though this potential has not yet been verified. We added new data to the original parameterization data set and our results show that the Fagacées formalism can be generalized. Context :The Fagacées growth and yield model was designed for the management of pure even-aged stands of European beech and served as a prototype to build models for other tree species. Aims: The objective of this study was to improve the growth components of the Fagacées model with additional data from NorthWestern France to SouthWestern Germany. Material and methods: Our model was calibrated on several forest inventory data sets. The first one (F) is the original data set that was used to elaborate the equations in the Fagacées model. The second one (F+) is the original data set extended with additional measurements on the same sites and on new sites in Northern France. The third (G) adds complementary data from a forest network in Southwestern Germany. The last one (A) is the aggregate of all these data sets. Results: Fitting the original model equations on the extended F+ dataset led us to modify the equation for stand basal area increment. This new equation also fit the German dataset well. The other equations could be applied to all datasets, some with the same parameter values and some after recalibrating according to the dataset. Conclusion: We conclude that the general form of the model's equations is appropriate for application to other regions, but that a recalibration of the equations is preferable in order to reflect local conditions. The advantage of our approach is that fewer data are required to recalibrate an existing equation than to establish an entirely new one.

ano.nymous@ccsd.cnrs.fr.invalid (Gilles Le Moguédec) 22 Sep 2021

https://hal.inrae.fr/hal-03351338v1

[hal-03424361] Mixture effect on radial stem and shoot growth differs and varies with temperature

The effect of species diversity on forest productivity and its temporal stability is known to be species-, climateand site-dependent and is mostly apprehended through stem diameter. Therefore, it remains largely unknown whether the mixture effect on the growth of tree crowns is similar to its effect on the growth of tree diameter. However, it is commonly accepted that changes in crown architecture are an important component of tree response to tree species diversity. Moreover, the mixture effect on species is often asymmetric, i.e. the effect of a species A on a species B is not equal to the effect of species B on A. It then appears that considering the effects of both species mixture and climate on shoot growth could contrast the results coming mainly from stem growth. We studied the effects of tree species mixture and temperature on the annual growth of shoots and basal area of stems in Fagus sylvatica-Quercus pubescens and Fagus sylvatica-Abies alba stands along a Mediterranean-Alpine gradient, for four years in five sites. The sample design was organized in 10 triplets: four triplets of mono-and bispecific plots of Quercus pubescens and Fagus sylvatica and six triplets of mono-and bi-specific plots of Abies alba and Fagus sylvatica along an altitudinal gradient ranging from 725 m to 1431 m. We found that the mixture effect on annual shoot volume increment (SVI) and on basal area increment (BAI) was asymmetrical in seven out of 10 cases and not significant in the three remaining cases. Mixture effect on SVI ranked from − 56% to 157% and on BAI it ranked from − 40% to 252%. Eventually we found that mixture effect was dependent on the type of limiting factor for growth, with at the driest sites a predominance of competition effects and at the coldest site a positive mixture effect on the two species studied. Branch growth appears as a variable that can be at least as informative as radial growth regarding the tree response to species interactions. This implies that considering only stem diameter in the diversity-productivity relationship can lead to biased conclusions on the global mixture effect on tree growth, which calls for a comprehensive approach of the tree response to tree species diversity. Our results are discussed in the light of the species stress tolerances and strategies to cope with competition.

ano.nymous@ccsd.cnrs.fr.invalid (Maude Toïgo) 10 Mar 2023

https://hal.inrae.fr/hal-03424361v1

[hal-02976274] Growth dynamics of fast-growing tree species in mixed forestry and agroforestry plantations

In recent years, plantations of fast-growing tree species have emerged as a possible way to meet the increasing demand for biomass for renewable energy in Europe. Agroforestry plantations including fast-growing tree species could be an attractive option because they reduce land competition for biomass and food production while providing forest benefits. Today, the species interactions that determine whether a given mixture will be more productive than the corresponding monocultures are still poorly understood. Our objective was to assess the performance of fast-growing trees, i.e. poplar (Populus nigra × P. deltoides) and alder (Alnus glutinosa), in association with herbaceous species either N 2-fixing species (succession alfalfa (Medicago sativa) and clover (Trifolium pratense)) or graminoids (succession of wheat (Triticum aestivum)-triticale (Triticosecale)-temporary grassland consisting of mixtures of perennial ryegrass (Lolium perenne) and fescue (Festuca ovina)), respectively, and in association together. We compared tree growth in mixed stands to growth in the respective tree monocultures. An experimental plantation composed of three blocks including the different treatments was set up in 2014 in northeastern France. In the forest mixture, poplar and alder were planted in alternating rows, and in the agro-forestry plots, every second line of trees was replaced by the crops. No fertilizers (of any kind) were used during the experiments. During six growing seasons, tree growth (height and diameter at breast height) was monitored monthly in the agroforestry stands, the forest mixture stand and the two tree monocultures. By the end of 2019, poplar stem height in association with N 2-fixing crops (alfalfa, then clover) was higher than in the forest mixture and the monoculture. During the warmest growing season with a marked dry period in June-July (2018), poplar height growth rate in the agroforestry treatment was between three and five times higher than for the poplars in the monoculture and the forest mixture. A facilitation process in the agroforestry plantations could explain this result due to a significant enrichment of the soil in nitrogen by the N 2-fixing crops. This result only appeared several years after tree planting, and management actions were necessary in order to control the strong competition between crops and trees during the early stages. In the forest mixture, poplars associated with alders were smaller than in their monoculture, in spite of a stratification of the canopies of the two species. For alders, tree growth did not appear to be affected by either an association with graminoids or with poplar.

ano.nymous@ccsd.cnrs.fr.invalid (Anaïs Thomas) 24 Oct 2022

https://hal.science/hal-02976274v1

[hal-03326748] Early effects of two planting densities on growth dynamics and water-use efficiency in Robinia pseudoacacia (L.) and Populus deltoides (Bartr. ex Marsh.) × P. nigra (L.) short rotation plantations

Context: Black locust (Robinia pseudoacacia L.) is an interesting tree species for woody biomass production. However, its potential for this purpose has been much less studied and characterized than that for species from the Salicaceae family (i.e., poplar and willow). Aims: The objective of our study was to evaluate the potential of black locust for biomass production as compared to that of poplar. Methods: We estimated biomass production, growth habit, and efficiency of water use of two provenances of black locust (1) compared to those of poplar (Populus deltoides Bartr. ex Marsh. × P. nigra L.), (2) at two planting densities, and (3) 2 and 4 years after planting. Results: Black locust had a very different growth habit, much higher biomass production, and larger water-use efficiency than poplar. These differences were exacerbated during the driest year of the experiment. However, black locust responded very badly to harvesting. Conclusion: Black locust was more productive and more efficient in terms of water use than poplar, especially during the driest year of the experiment.

ano.nymous@ccsd.cnrs.fr.invalid (Julien Toillon) 29 Aug 2022

https://hal.science/hal-03326748v1

[hal-03209549] Leafy season length is reduced by a prolonged soil water deficit but not by repeated defoliation in beech trees (Fagus sylvatica L.): comparison of response among regional populations grown in a common garden

Bud-burst and leaf-senescence determine the length of the growing season for deciduous trees and therefore the duration of potential carbon assimilation with consequences on biomass production. In Fagus sylvatica L., leaf phenology depends on both photoperiod and temperature. The future climate is expected to induce more frequent soil water deficits and biotic attacks (possibly resulting in severe defoliation). The aim of the study is to assess whether these constrains may alter leaf phenology. In a common garden, we sowed seeds collected from six beech forests along a small latitudinal gradient (140 km) in North-Eastern France. In 2014, after seven years growth, a rain exclusion was installed above the trees to test how recurrent soil water deficits impacted bud-burst (BB) and leaf-yellowing (LY) over three years. We also analyzed the response of leaf phenology to annual defoliation, aiming at affecting carbon and nitrogen availability in trees. Delayed BB and early LY were observed, reducing the growing season (GS) until 14 days in response to soil water deficit whereas no influence of defoliation was detected. These time lags were not in relation with leaf nitrogen content. In the control treatment, BB occurred earlier and LY later in the northernmost populations than in the southernmost without clear relationships with local climate. A significant treatment x population interaction was observed revealing a plasticity in the leaf phenology response to soil water deficit among populations. These results suggest that beech trees present a genetic differentiation of leaf phenology even within a small latitudinal gradient but that these differentiations could be disrupted by soil water deficit that is predicted to increase in the future.

ano.nymous@ccsd.cnrs.fr.invalid (Catherine Massonnet) 03 Feb 2023

https://hal.inrae.fr/hal-03209549v1

[hal-03981723] Dynamics of Foliar Responses to O3 Stress as a Function of Phytotoxic O3 Dose in Hybrid Poplar

With background concentrations having reached phytotoxic levels during the last century, tropospheric ozone (O 3) has become a key climate change agent, counteracting carbon sequestration by forest ecosystems. One of the main knowledge gaps for implementing the recent O 3 ux-based critical levels (CLs) concerns the assessment of effective O 3 dose leading to adverse effects in plants. In this study, we investigate the dynamics of physiological, structural, and morphological responses induced by two levels of O 3 exposure (80 and 100 ppb) in the foliage of hybrid poplar, as a function of phytotoxic O 3 dose (POD 0) and foliar developmental stage. After a latency period driven by foliar ontological development, the gas exchanges and chlorophyll content decreased with higher POD 0 monotonically. Hypersensitive response-like lesions appeared early during exposure and showed sigmoidal-like dynamics, varying according to leaf age. At current POD 1_SPEC CL, notwithstanding the aforementioned reactions and initial visible injury to foliage, the treated poplars had still not shown any growth or biomass reduction. Hence, this study demonstrates the development of a complex syndrome of early reactions below the ux-based CL, with response dynamics closely determined by the foliar ontological stage and environmental conditions. General agreement with patterns observed in the eld appears indicative of early O 3 impacts on processes relevant, e.g., biodiversity ecosystem services before those of economic signi cance-i.e., wood production, as targeted by ux-based CL.

ano.nymous@ccsd.cnrs.fr.invalid (Benjamin Turc) 10 Feb 2023

https://hal.univ-lorraine.fr/hal-03981723v1

[hal-03981721] Emerging challenges of ozone impacts on asian plants: actions are needed to protect ecosystem health

Context: Ozone concentrations near the land surface are rising in Asia while they are declining or stagnating in Europe and North America. Ozone is the most widespread air pollutant negatively affecting vegetation, and its increased concentrations pose a major threat to food quality and production and other ecosystem services in Asia. Method: In this review, we provide an overview of scientific challenges in the impacts of ozone pollution on Asian vegetation, and synthesize the challenges toward mitigation of the impacts. Result: We argue that new policy initiatives need to seek both reduction of ozone levels and enhancement of plant tolerance to ozone to maintain food quality and ensure food supplies. Conclusion: The scientific advancements must be transferred to actions by two types of institutions: a) environmental agencies for reducing ozone levels and b) agricultural research institutions for enhancing plant tolerance to ozone. In connecting the scientific advancements with the institutional actions, scientists in Asian countries should play the key role taking advantages of interdisciplinary and international collaborations.

ano.nymous@ccsd.cnrs.fr.invalid (Zhaozhong Feng) 10 Feb 2023

https://hal.univ-lorraine.fr/hal-03981721v1

[hal-03493025] Integrative role of plant mitochondria facing oxidative stress: The case of ozone

Ozone is a secondary air pollutant, which causes oxidative stress in plants by producing reactive oxygen species (ROS) starting by an external attack of leaf apoplast. ROS have a dual role, acting as signaling molecules, regulating different physiological processes and response to stress, but also inducing oxidative damage. The production of ROS in plant cells is compartmented and regulated by scavengers and specific enzyme pathways. Chronic doses of ozone are known to trigger an important increase of the respiratory process while decreasing photosynthesis. Mitochondria, which normally operate with usual levels of intracellular ROS, would have to play a prominent role to cope with an enhanced ozone-derived ROS production. It is thus needed to compile the available literature on the effects of ozone on mitochondria to precise their strategy facing oxidative stress. An overview of the mitochondrial fate in three steps is proposed, i) starting with the initial responses of the mitochondria for alleviating the overproduction of ROS by the enhancement of existing antioxidant metabolism and adjustments of the electron transport chain, ii) followed by the setting up of detoxifying processes through exchanges between mitochondria and the cell, and iii) ending by an accelerated senescence initiated by mitochondrial membrane permeability and leading to programmed cell death.

ano.nymous@ccsd.cnrs.fr.invalid (Anthony Gandin) 02 Jan 2023

https://hal.science/hal-03493025v1

[hal-04155557] Les observatoires des peuplements dévastés et mités après tempête, 1re partie

[...]

ano.nymous@ccsd.cnrs.fr.invalid (Lisa Laurent) 07 Jul 2023

https://hal.science/hal-04155557v1

[hal-04219519] Cutting tree rings into time slices: how intra‐annual dynamics of wood formation help decipher the space‐for‐time conversion

Tree-ring anatomy, microdensity and isotope records provide valuable intra-annual information. However, extracting signals at that scale is challenged by the complexity of xylogenesis, where two major processescell enlargement and wall thickeningoccur at different times and rates. We characterized the space-for-time association in the tree rings of three conifer species by examining the duration, overlapping, inter-tree synchronicity and interannual stability during cell enlargement and wall thickening across regular tree-ring sectors (portions of equal tangential width). The number of cells and cell differentiation rates determined the duration of sector formation, which augmented more rapidly throughout the ring for wall thickening than for enlargement. Increasing the number of sectors above c. 15 had a limited effect on improving time resolution because consecutive sector formation overlapped greatly in time, especially in narrow rings and during wall thickening. Increasing the number of sectors also resulted in lower synchronicity and stability of intermediate-sector enlargement, whereas all sectors showed high synchronicity and stability during wall thickening. Increasing the number of sectors had a stronger effect on enhancing time-series resolution for enlargement-than for wall-thickening-related traits, which would nevertheless produce more reliable intra-annual chronologies as a result of the more similar calendars across trees and years in wall thickening.

ano.nymous@ccsd.cnrs.fr.invalid (Gonzalo Pérez‐de‐lis) 27 Sep 2023

https://hal.inrae.fr/hal-04219519v1

[hal-04214003] Dynamiques forestières à l'ère anthropocène : mise au point sémantique et proposition de définitions écologiques

Dans cette mise au point sémantique, nous proposons de formaliser une série de définitions des termes les plus fréquemment utilisés pour qualifier une forêt selon son degré d’anthropisation. La forêt est appréhendée ici sous sa dimension écosystémique, incluant biotope et biocœnose. Dans un souci de robustesse conceptuelle, nous nous appuyons sur quatre théories scientifiques : la théorie des communautés végétales, la théorie des successions écologiques, la théorie des perturbations et la théorie de la hiérarchie, dont les contributions sont brièvement analysées. Sur cette base, nous reprenons un certain nombre de définitions et en proposons de nouvelles, de manière à qualifier une forêt selon quatre attributs fondamentaux : son origine et sa genèse ; son degré de naturalité ; son historicité et sa morphologie. Chaque définition est explicitée, argumentée et illustrée à l’aide d’exemples concrets. Nous concluons par une réflexion ouverte sur le concept d’état de référence pour une forêt.

ano.nymous@ccsd.cnrs.fr.invalid (Guillaume Decocq) 21 Sep 2023

https://hal.inrae.fr/hal-04214003v1

[hal-04155358] Les observatoires des peuplements dévastés et mités après tempête, 2e partie

[...]

ano.nymous@ccsd.cnrs.fr.invalid (Lisa Laurent) 07 Jul 2023

https://hal.science/hal-04155358v1

[hal-03168867] Historical ecology of Mediterranean forests: Land use legacies on current understorey plants differ with time since abandonment and former agricultural use

Questions: Land use legacies in current forest understorey vegetation, thoroughly studied in temperate regions, were investigated in a Mediterranean context. We tested the effect of three historical variables on current forest plant communities and traits: forest temporal continuity (ancient: forested before 1860, recent: reforested after 1860, and very recent forest: reforested after 1958) and type of land use in 1860 and 1958 (forest, pasture or arable land). Location: The Regional Natural Park of Luberon (southeastern France). Methods: We used a comprehensive vegetation plot database (473 species in 1,429 plots). Species’ response to historical variables was tested with logistic regressions, and the relationship between plant traits and historical variables was analysed with RLQ and fourth‐corner analyses. Results: Among all studied species, 250 responded to forest temporal continuity, 208 to 1860 land use, and 246 to 1958 land use. Species associated with ancient forests were more frequently forest specialists or forest edge species, shade‐tolerant and perennials, while species associated with recent and very recent forests were more frequently annuals, anemochorous and heliophilous species. Species exhibited different traits and ecological preferences according to the type of land use prior to forest: therophytes were more frequent on former arable land while chamaephytes were more frequent on former pasture. Trait responses to 1860 and 1958 land uses were globally consistent. Conclusions: The effect of forest temporal continuity and past land use on forest understorey communities was consistent with other studies in northern Europe or northern America, which suggests that the same ecological processes apply in temperate lowland and Mediterranean regions. This study highlights a succession of plant communities in the long term and different trajectories of succession according to the type of former agricultural use. The long‐term legacies of past land use in current forest plant communities highlight the importance to preserve ancient forests, where typical forest species can be maintained.

ano.nymous@ccsd.cnrs.fr.invalid (Juliet Abadie) 19 Apr 2021

https://hal.science/hal-03168867v1

[hal-03361243] Four-year-performance of oak and pine seedlings following mechanical site preparation with lightweight excavators

Mechanical site preparation methods that used tools mounted on lightweight excavators and that provided localised intensive preparation were tested in eight experimental sites across France where the vegetation was dominated either by (L.) Moench or (L.) Kuhn. Two lightweight tools (Deep Scarifier: DS; Deep Scarifier followed by Multifunction Subsoiler: DS+MS) were tested in pine ( L., var. (Loudon) Hyl. or Aiton) and oak ( (Matt.) Liebl. or L.) plantations. Regional methods commonly used locally (herbicide, disk harrow, mouldboard plow) and experimental methods (repeated herbicide application; untreated control) were used as references in the experiments. Neighbouring vegetation cover, seedling survival, height and basal diameter were assessed over three to five years after plantation. For pines growing in , seedling diameter after four years was 37% and 98% greater in DS and DS+MS, respectively, than in the untreated control. For pines growing in , it was 62% and 107% greater in the same treatments. For oak, diameter was only 4% and 15% greater in , and 13% and 25% greater in , in the same treatments. For pines, the survival rate after four years was 26% and 32% higher in and 64% and 70% higher in , in the same treatments. For oak, it was 3% and 29% higher in and 37% and 31% higher in . Herbicide, when applied for three or four years after planting, provided the best growth performances for pines growing in and and for oaks growing in . For these species and site combinations, DS+MS and DS treatments reduced the neighbouring vegetation cover for one to four years following site preparation. Molinia caerulea Pteridium aquilinum Pinus sylvestris Pinus nigra corsicana Pinus pinaster Quercus petraea Quercus robur M. caerulea P. aquilinum M. caerulea P. aquilinum M. caerulea P. aquilinum M. caerulea P. aquilinum M. caerulea P. aquilinum P. aquilinum.

ano.nymous@ccsd.cnrs.fr.invalid (Noé Dumas) 10 Nov 2021

https://hal.inrae.fr/hal-03361243v1

[hal-03628978] An innovative and automated method for characterizing wood defects on trunk surfaces using high-density 3D terrestrial LiDAR data

Context: Ground-based light detection and ranging (LiDAR) technology describes standing trees with a high level of detail. This provides an opportunity to assess standing tree quality and to use this information in forest inventory. Assuming the availability of a very high level of detail, we could extract information about the surface defects, mainly inherited from past ramification and having a strong impact on wood quality. Aims: Within the general framework of the development of a computing method able to detect, identify, and quantify the defects on the trunk surface described from 3D data produced by a terrestrial LiDAR, this study focuses on the relevance of the whole process for two tree species with contrasted bark roughness (Quercus petraea (Matt.) Liebl. and Fagus sylvatica L.) in terms of detection, identification of the defects, and comparison with measurements performed manually on the bark surface. Methods: First, a segmentation algorithm detected singularities on the trunk surface. Next, a Random Forests machine learning algorithm identified the most probable defect type and allowed the elimination of false detections. Finally, we estimated the position, horizontal, and vertical dimensions of each defect from 3D data, and we compared them to those observed directly on the trunk by an operator. Results: The defects were detected and classified with a high accuracy with an average F1 score (harmonic mean of precision and recall) of 0.74. There were differences in computed and observed defect areas, but a much closer agreement for the number of defects. Conclusion: The information about the defects present on the trunk surface measured from terrestrial LiDAR data can be used in an automated procedure for grading standing trees or roundwoods

ano.nymous@ccsd.cnrs.fr.invalid (Van-Tho Nguyen) 04 Apr 2022

https://hal.science/hal-03628978v1

[hal-03334029] Vertical variations in wood basic density for two softwood species

Studies on wood basic density (BD) vertical variations become essential to predict more accurately the within-stem distributions of biomass and wood quality in the forest resource. The vertical variation of wood BD in the stem has been little studied until now, most BD studies being based on measurements taken at breast height. The main objective of this work was to observe and to understand the patterns of vertical BD variation within stems in relation to classical dendrometric variables and to propose relevant equation forms for future modelling. Two softwood species were studied: Abies alba and Pseudotsuga menziesii. Contrasted thinning intensities were studied including strongly thinned plots versus control plots without thinning. BD was most of the time highest at the base of the tree for both species. Then, after a strong decrease from the base of the tree, an increase in BD was often observed towards the top of the tree especially for A. alba. The variation in BD with height was stronger for the unthinned plots than for the heavily thinned ones of A. alba. The opposite was observed for Ps. menziesii. The modulation of growth rate and tree size through thinning intensities modifies the observed vertical variations in BD. Two types of biexponential models were proposed to describe BD variations. The first model used the height in the stem and classical easily-measurable tree variables as inputs, the other one additionally used BD at breast height (BD130). The relative RMSE of BD for A. alba and Ps. menziesii were 9.9% and 8.1%, respectively, with the model without BD130 and 7.6% and 5.9%, respectively, with the model including BD130.

ano.nymous@ccsd.cnrs.fr.invalid (Antoine Billard) 29 Aug 2024

https://hal.science/hal-03334029v1

[hal-03145053] Intraspecific variability of quantity and chemical composition of ethanolic knotwood extracts along the stems of three industrially important softwood species: Abies alba , Picea abies and Pseudotsuga menziesii

Knotwood of softwood species is rich in secondary metabolites, especially lignans. These metabolites can be extracted with organic solvents, and are known to be valuable sources of natural bioactive molecules. Here, we examine the intraspecific variability of the yield and compositions of ethanol extracts from knotwood along the stems of three economically significant softwoods Abies alba, Picea abies and Pseudotsuga menziesii in view of further valorisation. Extractive yields from all three species were higher from knots at the base of the living crown than at the top. Lignans and terpenes were abundant in A. alba and P. abies extracts, and lignans were present in the highest concentrations at the crown base. Secoisolariciresinol and hydroxymatairesinol were the most abundant lignans in A. alba and P. abies, respectively. P. menziesii extract composition was more diverse than those of the other species, containing taxifolin, small amounts of the lignan nortrachelogenin, and smaller amounts of secoisolariciresinol. A cyclitol, D-pinitol, was found in high concentrations in extracts from knots at the very top of the crown, particularly in A. alba and P. menziesii. Lignans, taxifolin and D-pinitol are reported to have anti-tumour properties, and valuable food-supplement markets exist for these compounds suggesting possibilities of further valorisation.

ano.nymous@ccsd.cnrs.fr.invalid (Maree Brennan) 18 Feb 2021

https://hal.science/hal-03145053v1

[hal-02735790] The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees

Leaf phenology is a major driver of ecosystem functioning in temperate forests and a robust indicator of climate change. Both the interannual and inter-population variability of leaf phenology have received much attention in the literature; in contrast, the withinpopulation variability of leaf phenology has been far less studied. Beyond its impact on individual tree physiological processes, the within-population variability of leaf phenology can affect the estimation of the average budburst or leaf senescence dates at the population scale. Here, we monitored the progress of spring and autumn leaf phenology over 14 tree populations (9 tree species) in six European forests over the period of 2011 to 2018 (yielding 16 site-years of data for spring, 14 for autumn). We monitored 27 to 512 (with a median of 62) individuals per population. We quantified the within-population variability of leaf phenology as the standard deviation of the distribution of individual dates of budburst or leaf senescence (SDBBi and SDLSi, respectively). Given the natural variability of phenological dates occurring in our tree populations, we estimated from the data that a minimum sample size of 28 (resp. 23) individuals, are required to estimate SDBBi (resp. SDLSi) with a precision of 3 (resp. 7) days. The within-population of leaf senescence (average SDLSi = 8.5 days) was on average two times larger than for budburst (average SDBBi = 4.0 days). We evidenced that warmer temperature during the budburst period and a late average budburst date were associated with a lower SDBBi, as a result of a quicker spread of budburst in tree populations, with a strong species effect. Regarding autumn phenology, we observed that later senescence and warm temperatures during the senescence period were linked with a high SDLSi, with a strong species effect. The shares of variance explained by our models were modest suggesting that other factors likely influence the within-population variation in leaf phenology. For instance, a detailed analysis revealed that summer temperatures were negatively correlated with a lower SDLSi.

ano.nymous@ccsd.cnrs.fr.invalid (Rémy Denéchère) 07 Dec 2022

https://hal.inrae.fr/hal-02735790v1

[hal-04229676] A comprehensive framework for seasonal controls of leaf abscission and productivity in evergreen broadleaved tropical and subtropical forests

Three climate-phenology regimes are identified across tropical and subtropical forest biomes-Where light and water limit plant in dry season, litterfall and productivity peak in sunny wet season-Where light or water alternately limits plant, productivity peaks in wet season with low litterfall-Where water does not limit plant, litterfall and productivity peak in sunny dry season ll www.cell.com/the-innovation

ano.nymous@ccsd.cnrs.fr.invalid (Xueqin Yang) 05 Oct 2023

https://hal.science/hal-04229676v1

[hal-04674563] The three major axes of terrestrial ecosystem function

The leaf economics spectrum[1,2] and the global spectrum of plant forms and functions[3] revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species[2]. Ecosystem functions depend on environmental conditions and the traits of species that comprise the ecological communities[4]. However, the axes of variation of ecosystem functions are largely unknown, which limits our understanding of how ecosystems respond as a whole to anthropogenic drivers, climate and environmental variability[4,5]. Here we derive a set of ecosystem functions[6] from a dataset of surface gas exchange measurements across major terrestrial biomes. We find that most of the variability within ecosystem functions (71.8%) is captured by three key axes. The first axis reflects maximum ecosystem productivity and is mostly explained by vegetation structure. The second axis reflects ecosystem water-use strategies and is jointly explained by variation in vegetation height and climate. The third axis, which represents ecosystem carbon-use efficiency, features a gradient related to aridity, and is explained primarily by variation in vegetation structure. We show that two state-of-the-art land surface models reproduce the first and most important axis of ecosystem functions. However, the models tend to simulate more strongly correlated functions than those observed, which limits their ability to accurately predict the full range of responses to environmental changes in carbon, water and energy cycling in terrestrial ecosystems[7,8]. © 2021. The Author(s).

ano.nymous@ccsd.cnrs.fr.invalid (Mirco Migliavacca) 21 Aug 2024

https://hal.science/hal-04674563v1

[hal-03463575] Modelling bark volume for six main tree species in France: Assessment of models and application at regional scale.

Key message A set of models of bark thickness at breast height and bark volume are now available for six species in France. A common model suitable for predicting bark volume was proposed for all species. A small but significant altitude effect on bark thickness at breast height was detected for three species. Context The growing demand for wood energy and bio-molecules requires a thorough evaluation of forest biomass, particularly bark. Aims The objective of this study is to have statistical models of bark volumes for the six main forest species present in North-Eastern France and to be able to estimate regional bark biomasses and quantities of chemical extractives at regional scale. Methods A large databank gathering bark thickness measured at different heights in France was used for selecting literature or new alternative models of tree bark volume. These models were applied to the available forest inventory data from North-Eastern France to estimate the regional bark volume. Secondly, by multiplying these volumes by basic density data and extractive content recently obtained, bark biomasses and extractives quantities were deduced. Results The first results consist in a set of species-specific models of bark thickness at breast height with R-2 around 0.70 and a relative RMSE around 30% which is an improvement of 0.1 for R-2 and of 1-2% for relative RMSE depending on the species compared to the best models from the literature. The second results consist in a set of species-specific models of tree bark volumes with R-2 of 0.90 and a relative RMSE which varies between 22% when bark thickness at breast height is included and 40% when it is predicted. A significant relationship between bark thickness at breast height and altitude was also observed. The bark resources of Grand Est and Bourgogne-Franche-Comte regions were estimated at 558 000 m(3)/year and 611 000 m(3)/year respectively representing between 5.5% and 15% of the stem volume depending on the species. The propagation of the measurement error of bark gauge was estimated at 5% for model of bark thickness at breast height and 24% for bark volume model. Conclusion These results constitute an important contribution for a better knowledge of the bark resource at a regional scale and may help to optimise bark valuation by the forest-wood sector.

ano.nymous@ccsd.cnrs.fr.invalid (Rodolphe Bauer) 02 Dec 2021

https://agroparistech.hal.science/hal-03463575v1

[hal-03880251] Climate sensitivity and drought seasonality determine post-drought growth recovery of Quercus petraea and Quercus robur in Europe

Recent studies have identified strong relationships between delayed recovery of tree growth after drought and tree mortality caused by subsequent droughts. These observations raise concerns about forest ecosystem services and post-drought growth recovery given the projected increase in drought frequency and extremes. For quantifying the impact of extreme droughts on tree radial growth, we used a network of tree-ring width data of 1689 trees from 100 sites representing most of the distribution of two drought tolerant, deciduous oak species (Quercus petraea and Quercus robur). We first examined which climatic factors and seasons control growth of the two species and if there is any latitudinal, longitudinal or elevational trend. We then quantified the relative departure from pre-drought growth during droughts, and how fast trees were able to recover the pre-drought growth level. Our results showed that growth was more related to precipitation and climatic water balance (precipitation minus potential evapotranspiration) than to temperature. However, we did not detect any clear latitudinal, longitudinal or elevational trends except a decreasing influence of summer water balance on growth of Q. petraea with latitude. Neither species was able to maintain the pre-drought growth level during droughts. However, both species showed rapid recovery or even growth compensation after summer droughts but displayed slow recovery in response to spring droughts where none of the two species was able to fully recover the pre-drought growth-level over the three post-drought years. Collectively, our results indicate that oaks which are considered resilient to extreme droughts have also shown vulnerability when droughts occurred in spring especially at sites where long-term growth is not significantly correlated with climatic factors. This improved understanding of the role of drought seasonality and climate sensitivity of sites is key to better predict trajectories of post-drought growth recovery in response to the drier climate projected for Europe.

ano.nymous@ccsd.cnrs.fr.invalid (Arun Bose) 02 Dec 2022

https://agroparistech.hal.science/hal-03880251v1

[hal-03261880] Global transpiration data from sap flow measurements: the SAPFLUXNET database

Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.

ano.nymous@ccsd.cnrs.fr.invalid (Rafael Poyatos) 16 Jun 2021

https://hal.inrae.fr/hal-03261880v1

[hal-02934522] Estimation of dairy goat body composition: A direct calibration and comparison of eight methods

The objective was to compare eight methods for estimation of dairy goat body composition, by calibrating against chemical composition (water, lipid, protein, mineral and energy) measured post-mortem. The methods tested on 20 Alpine goats were body condition score (BCS), 3-dimension imaging (3D) automatic assessment of BCS or whole body scan, ultrasound, computer tomography (CT), adipose cell diameter, deuterium oxide dilution space (D 2 OS) and bioelectrical impedance spectroscopy (BIS). Regressions were tested between predictive variates derived from the methods and empty body (EB) composition. The best equations for estimation of EB lipid mass included BW combined with i) perirenal adipose tissue mass and cell diameter (R 2 = 0.95, residual standard deviation, rSD = 0.57 kg), ii) volume of fatty tissues measured by CT (R 2 = 0.92, rSD = 0.76 kg), iii) D 2 OS (R 2 = 0.91, rSD = 0.85 kg), and iv) resistance at infinite frequency from BIS (R 2 = 0.87, rSD = 1.09 kg). The D 2 OS combined with BW provided the best equation for EB protein mass (R 2 = 0.97, rSD = 0.17 kg), whereas BW alone provided a fair estimate (R 2 = 0.92, rSD = 0.25 kg). Sternal BCS combined with BW provided good estimation of EB lipid and protein mass (R 2 = 0.80 and 0.95, rSD = 1.27 and 0.22 kg, respectively). Compared to manual BCS, BCS by 3D slightly decreased the precision of the predictive equation for EB lipid (R 2 = 0.74, rSD = 1.46 kg), and did not improve the estimation of EB protein compared with BW alone. Ultrasound measurements and whole body 3D imaging methods were not satisfactory estimators of body composition (R 2 ≤ 0.40). Further developments in body composition techniques may contribute for high-throughput phenotyping of robustness.

ano.nymous@ccsd.cnrs.fr.invalid (Sylvain Lerch) 09 Sep 2020

https://hal.inrae.fr/hal-02934522v1

[hal-03299186] Mixing beech with fir or pubescent oak does not help mitigate drought exposure at the limit of its climatic range

In the context of climate change, it remains unclear whether mixed-species forests will help mitigate the impacts of future droughts and, if so, through which processes. As European beech (Fagus sylvatica L.) is one of the major European species, it is crucial to evaluate its response to drought when mixed with species with contrasted functional traits and in contrasted climatic conditions, particularly at the limit of its climatic range. This study aimed to (i) characterize the effects of tree species interactions on the drought exposure of beech in southeastern France, and (ii) determine whether belowground water uptake complementarity underlies these effects. We focused on beech-silver fir (Abies alba Mill.) and beech-pubescent oak (Quercus pubescens Willd.) forests across six sites in the French pre-Alps, a region at the limit of the climatic range for beech. We used a triplet approach to compare the tree-ring carbon isotope composition (δ 13 C) of these species in pure and two-species mixed stands during a period of dry years, and used water hydrogen isotope composition (δ 2 H) in the xylem to identify water uptake sources. Overall, we found no clear mixture effect pattern on beech physiological functioning among sites and triplets. In beech-fir sites, mixing beech with fir had no effect on beech δ 13 C values during dry years. In beech-oak sites, mixture effects on beech were mostly neutral, although sometimes beech suffered from a stronger exposure to drought in mixed stands. Our study emphasizes the impact of the tree sampling design on the outcome of studies on forest biodiversity-ecosystem functioning relationships. Limiting tree sampling to dominant trees when analyzing stand-level relationships may bias these outcomes. We evidenced differences in water uptake sources between beech and fir, but not between beech and oak during a dry summer. However, these patterns did not help explain the lack of species mixture effects, or existence thereof, at the triplet scale. Our study demonstrates that managing beech in mixed stands with silver fir or pubescent oak at the limit of beech climatic range does not buffer drought impacts on beech during dry years. In the long term, with more frequent extreme droughts, promoting beech-fir mixtures will not be detrimental to beech drought response, while beech may suffer in mixtures with pubescent oak.

ano.nymous@ccsd.cnrs.fr.invalid (Soline Martin-Blangy) 09 Aug 2021

https://hal.science/hal-03299186v1

[hal-03048359] Tree species identity drives soil organic carbon storage more than species mixing in major two-species mixtures (pine, oak, beech) in Europe

Mixed forests are usually associated with higher aboveground carbon storage compared to the corresponding monocultures but information on the impact of tree species mixing on soil organic carbon (SOC) is still limited. Yet, maximizing SOC storage is crucial for ecosystem C sequestration and many other ecosystem services. This study used a triplet approach (ie. two-species mixed stand and respective pure stands at the same site) to assess the impact of tree species identity and mixing on SOC storage in eight pine-oak, eight pine-beech and five beech-oak triplets in Europe. We sampled the forest floor (FF) and 0–40 cm in the mineral soil per 10 cm interval. For each triplet type, we fitted basal area (BA) proportion of one component species (for species identity) and a BA-based plot-level True Shannon Diversity index (for species mixing) as explanatory variables for SOC stocks in linear mixed effects models, which included stone content and plot BA as covariates, and site as a random intercept. Considering the total soil depth (FF + 0–40 cm), species identity effect on SOC stocks was only significant for pine-beech and pine-oak triplets but explained more variability in SOC stocks than species mixing across triplet types. Species mixing effect was not significant for any triplet type in the total soil depth. While species identity consistently drove SOC storage in the topsoil layers across triplet types, species mixing explained more variability in SOC stocks in the deeper soil layers except for pine-oak triplets. The results showed that species identity is a stronger driver of SOC storage than species mixing. While tree species identity effect was strongly related to a conifers vs broadleaves signature, the drivers behind mixing effects remained elusive. The results suggest that targeted selection of tree species could better enhance SOC storage in European forests than a mere increase in species richness.

ano.nymous@ccsd.cnrs.fr.invalid (Richard Osei) 28 Jan 2025

https://hal.inrae.fr/hal-03048359v1

[hal-03013971] Scientific and human errors in a snow model intercomparison

Twenty-seven models participated in the Earth System Model - Snow Model Intercomparison Project (ESM-SnowMIP), the most data-rich MIP dedicated to snow modelling. Our findings do not support the hypothesis advanced by previous snow MIPs: evaluating models against more variables, and providing evaluation datasets extended temporally and spatially does not facilitate identification of key new processes requiring improvement to model snow mass and energy budgets, even at point scales. In fact, the same modelling issues identified by previous snow MIPs arose: albedo is a major source of uncertainty, surface exchange parametrizations are problematic and individual model performance is inconsistent. This lack of progress is attributed partly to the large number of human errors that led to anomalous model behaviour and to numerous resubmissions. It is unclear how widespread such errors are in our field and others; dedicated time and resources will be needed to tackle this issue to prevent highly sophisticated models and their research outputs from being vulnerable because of avoidable human mistakes. The design of and the data available to successive snow MIPs were also questioned. Evaluation of models against bulk snow properties was found to be sufficient for 15 some but inappropriate for more complex snow models whose skills at simulating internal snow properties remained untested. Discussions between the authors of this paper on the purpose of MIPs revealed varied, and sometimes contradictory, motivations behind their participation. These findings started a collaborative effort to adapt future snow MIPs to respond to the diverse needs of the community

ano.nymous@ccsd.cnrs.fr.invalid (Cecile Menard) 19 Nov 2020

https://hal.science/hal-03013971v1

[hal-03465112] Nutrient supply modulates species interactions belowground: dynamics and traits of fine roots in mixed plantations of Eucalyptus and Acacia mangium

Aims : Belowground interactions are still poorly understood in mixed-species forests. We investigated the effects of soil fertility on belowground processes in mixed planted forests. Methods : The dynamics and traits of Eucalyptus and Acacia mangium fine roots (diameter < 2 mm) in plantations with 50% of each species were studied in a randomized block design established in a nutrient depleted soil. Stands with NPK fertilization applied at planting (F+) were compared to unfertilized stands (F-). Results : In the 0–15 cm soil layer, Eucalyptus root mass density (RMD) was higher than Acacia RMD by 50% in F+ and 10% in F-, considering both ages. At 34 months of age, Eucalyptus RMD was 94% higher near Acacia trees than near Eucalyptus trees in F-. In this layer, Eucalyptus specific root length (SRL) was 21% higher than Acacia SRL at 16 months of age and was 10% higher in F- than in F+ at 34 months of age. The cumulative Eucalyptus fine root length production between 16 and 34 months was 66% higher in F- than in F+ in the 0–1 m soil layer. Conclusions : Fertilization increased the competition between species and led to a partial exclusion of Acacia fine roots from the nutrient-rich topsoil. Soil exploration by Eucalyptus roots in the vicinity of Acacia trees was higher in F- than in F+, which suggests that unfertilized trees benefited from facilitation through higher soil N availability and direct N transfer from Acacia trees.

ano.nymous@ccsd.cnrs.fr.invalid (Bruno Bordron) 03 Dec 2021

https://hal.inrae.fr/hal-03465112v1

[hal-03702387] Biodiversity Protection in Private Forests: PES Schemes, Institutions and Prosocial Behavior

The overall research question addresses the effectiveness of incentive mechanisms in poli -cies that enhance private forest owners’ biodiversity protection. In particular, the paper focuses on the link between forest owners’ motivations, incentives, and institutions, and questions the incentives of the current biodiversity protection policies. Our hypothesis is that the purely monetary nature of the incentives can cause a “crowding out effect”, i.e., forest owners may reduce their voluntary contribution to biodiversity protection that is driven by prosocial motivations (altruism, self-image, etc.). With this in mind, as well as the knowledge acquired via this project about forest owners’ motivations, we looked for the most effective combinations of “incentive mechanisms” (monetary and non-monetary) and “institutions” (national and local authorities, NGOs, etc.) to encourage forest owners to adopt biodiversity protection measures in their forests.

ano.nymous@ccsd.cnrs.fr.invalid (Jens Abildtrup) 25 Oct 2023

https://hal.science/hal-03702387v1

[hal-03174198] Pulse labelling of deep soil layers in forest with 13 CH 4 : testing a new method for tracing methane in the upper horizons, understorey vegetation and tree stems using laserbased spectrometry

Methane emissions from plants in wetlands are mainly due to internal transport, from the anoxic soil layers where methane is produced, to the atmosphere. This pathway has not yet been clearly demonstrated for upland forest vegetation, where methane can be produced in deep soil layers. We developed a new method to trace methane transfer from the deep soil. We conducted a 13 CH 4 pulse labelling at 40-cm soil depth and then monitored 13 CH 4 in the upper horizons, at the soil surface (with or without understorey vegetation) and emitted by tree stems until the total disappearance of the labelled gas. Most of the injected 13 CH 4 was oxidized in the soil despite high soil water content. The understorey vegetation did not contribute to 13 CH 4 emission by the soil. We prove that tree stems can emit methane produced in an upland forest soil, even when the said soil is a net methane sink. We conclude that pulse labelling with 13 CH 4 and tracing by laser-based spectrometry is a promising tool approach to study the transport of methane from production to emission.

ano.nymous@ccsd.cnrs.fr.invalid (Caroline Plain) 19 Mar 2021

https://hal.univ-lorraine.fr/hal-03174198v1

[hal-03412975] Are differences among forest tree populations in carbon isotope composition an indication for adaptation to drought?

[...]

ano.nymous@ccsd.cnrs.fr.invalid (Oliver Brendel) 23 Nov 2021

https://hal.inrae.fr/hal-03412975v1

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Productions 2021

HAL : Dernières publications

[hal-04528777] Improvement of modeling plant responses to low soil moisture in JULESvn4.9 and evaluation against flux tower measurements

[hal-03483916] Phenotypic and genotypic data of a European beech (Fagus sylvatica L.) progeny trial issued from three plots along an elevation gradient in Mont Ventoux, South-Eastern France

[hal-03123656] OSIP1 is a self‐assembling DUF3129 protein required to protect fungal cells from toxins and stressors

[hal-03293479] The climatic debt is growing in the understorey of temperate forests: Stand characteristics matter

[hal-03282821] The GenTree Platform: growth traits and tree-level environmental data in 12 European forest tree species

[hal-03167847] Recent increase in European forest harvests as based on area estimates (Ceccherini et al. 2020a) not confirmed in the French case

[hal-03423711] Quels besoins de connaissances pour le futur des forêts en France ? Au-delà du plan de relance

[hal-03363005] Climate and socio-economic factors explain differences between observed and expected naturalization patterns of European plants around the world

[hal-03466115] A generic information framework for decision-making in a forest-based bio-economy

[hal-02930429] Genomic and phenotypic divergence unveil microgeographic adaptation in the Amazonian hyperdominant tree Eperua falcata Aubl. (Fabaceae)

[hal-03516967] Retrieval and validation of forest background reflectivity from daily Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) data across European forests

[hal-03278925] Method comparison of indirect assessments of understory leaf area index (LAIu): A case study across the extended network of ICOS forest ecosystem sites in Europe

[hal-03134066] C-STABILITY an innovative modeling framework to leverage the continuous representation of organic matter

[hal-03037249] Mixing has limited impacts on the foliar nutrition of European beech and Scots pine trees across Europe

[hal-03334205] Numerical classification of the Carici caryophylleae-Genistetea lobelii in Corsica (France)

[hal-03889520] Climate change impact on tree mortality differs with tree social status

[hal-04226966] Drought elicits contrasting responses on the autumn dynamics of wood formation in late successional deciduous tree species

[hal-03265612] Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient

[hal-04226953] SabaTracheid 1.0: A Novel Program for Quantitative Analysis of Conifer Wood Anatomy — A Demonstration on African Juniper From the Blue Nile Basin

[hal-03351338] Improving the Fagacées growth model with an expanded common beech (Fagus sylvatica L.) data series from France and Germany

[hal-03424361] Mixture effect on radial stem and shoot growth differs and varies with temperature

[hal-02976274] Growth dynamics of fast-growing tree species in mixed forestry and agroforestry plantations

[hal-03326748] Early effects of two planting densities on growth dynamics and water-use efficiency in Robinia pseudoacacia (L.) and Populus deltoides (Bartr. ex Marsh.) × P. nigra (L.) short rotation plantations

[hal-03209549] Leafy season length is reduced by a prolonged soil water deficit but not by repeated defoliation in beech trees (Fagus sylvatica L.): comparison of response among regional populations grown in a common garden

[hal-03981723] Dynamics of Foliar Responses to O3 Stress as a Function of Phytotoxic O3 Dose in Hybrid Poplar

[hal-03981721] Emerging challenges of ozone impacts on asian plants: actions are needed to protect ecosystem health

[hal-03493025] Integrative role of plant mitochondria facing oxidative stress: The case of ozone

[hal-04155557] Les observatoires des peuplements dévastés et mités après tempête, 1re partie

[hal-04219519] Cutting tree rings into time slices: how intra‐annual dynamics of wood formation help decipher the space‐for‐time conversion

[hal-04214003] Dynamiques forestières à l'ère anthropocène : mise au point sémantique et proposition de définitions écologiques

[hal-04155358] Les observatoires des peuplements dévastés et mités après tempête, 2e partie

[hal-03168867] Historical ecology of Mediterranean forests: Land use legacies on current understorey plants differ with time since abandonment and former agricultural use

[hal-03361243] Four-year-performance of oak and pine seedlings following mechanical site preparation with lightweight excavators

[hal-03628978] An innovative and automated method for characterizing wood defects on trunk surfaces using high-density 3D terrestrial LiDAR data

[hal-03334029] Vertical variations in wood basic density for two softwood species

[hal-03145053] Intraspecific variability of quantity and chemical composition of ethanolic knotwood extracts along the stems of three industrially important softwood species: Abies alba , Picea abies and Pseudotsuga menziesii

[hal-02735790] The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees

[hal-04229676] A comprehensive framework for seasonal controls of leaf abscission and productivity in evergreen broadleaved tropical and subtropical forests

[hal-04674563] The three major axes of terrestrial ecosystem function

[hal-03463575] Modelling bark volume for six main tree species in France: Assessment of models and application at regional scale.

[hal-03880251] Climate sensitivity and drought seasonality determine post-drought growth recovery of Quercus petraea and Quercus robur in Europe

[hal-03261880] Global transpiration data from sap flow measurements: the SAPFLUXNET database

[hal-02934522] Estimation of dairy goat body composition: A direct calibration and comparison of eight methods

[hal-03299186] Mixing beech with fir or pubescent oak does not help mitigate drought exposure at the limit of its climatic range

[hal-03048359] Tree species identity drives soil organic carbon storage more than species mixing in major two-species mixtures (pine, oak, beech) in Europe

[hal-03013971] Scientific and human errors in a snow model intercomparison

[hal-03465112] Nutrient supply modulates species interactions belowground: dynamics and traits of fine roots in mixed plantations of Eucalyptus and Acacia mangium

[hal-03702387] Biodiversity Protection in Private Forests: PES Schemes, Institutions and Prosocial Behavior

[hal-03174198] Pulse labelling of deep soil layers in forest with 13 CH 4 : testing a new method for tracing methane in the upper horizons, understorey vegetation and tree stems using laserbased spectrometry

[hal-03412975] Are differences among forest tree populations in carbon isotope composition an indication for adaptation to drought?