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[hal-05775477] Discrepancies between Sentinel-2 and LiDAR-derived LAI in temperate deciduous forests: Influence of apparent optical depth, radiative transfer priors, and horizontal heterogeneity
Accurate estimation of forest leaf area index (LAI) from satellite images remains challenging due to limited sunlight penetration and intricate scattering through structurally complex canopies. We compared LAI estimated from radiative transfer model PROSAIL hybrid inversion applied to Sentinel-2 (S2) images with LAI derived from airborne LiDAR across three temperate deciduous forests in France. We assessed three factors driving discrepancies between the two estimates: (1) the attenuation of the optical signal reducing the apparent canopy depth contributing to S2 reflectance, (2) the parametrisation of the PROSAIL inversion, and (3) the local horizontal heterogeneity in canopy height. Sentinel-2 LAI estimates most closely matched LiDAR-derived LAI when the latter was restricted to the upper 6–10 m of canopy thickness. Optimising the range of PROSAIL parameters through a multi-criteria Pareto framework reduced the reported inter-sensor RMSE values in LAI by 1.2 m2/m2 and the Bias by 1.54m2/m2, on average, across sites and relative to the algorithm theoretical basis document (ATBD) baseline. Yet, residual discrepancies remained largest in stands with strong horizontal heterogeneity within S2 pixels at Aigoual and Mormal. Leaf mass per area could be retained at default values, while average leaf angle, leaf brown pigment content and the LAI distribution all required forest-adapted priors. Most of that improvement transferred between forested areas. A configuration based on two sites, with no LiDAR-derived prior, achieved 62% of the maximum attainable RMSE reduction and 57% of the Bias reduction when transferred to the third site. The LiDAR-derived LAI prior contributed to a maximum of 17% of the overall RMSE reduction across the three study sites. Our findings highlight the importance of jointly accounting for canopy thickness and horizontal heterogeneity when retrieving LAI from passive optical sensors, and suggest that future forest monitoring efforts may benefit from LiDAR-informed calibration of hybrid radiative transfer model inversion.
ano.nymous@ccsd.cnrs.fr.invalid (Nathan Corroyez) 02 Oct 2026
https://hal.science/hal-05775477v1
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[hal-05731617] FORMSpoT: Revealing fine-scale forest disturbances from nation-wide 1.5 m forest canopy height time series
Current large-scale satellite-based forest disturbance monitoring systems operate at 10-30 m resolution, which is too coarse to detect changes at the scale of individual trees resulting in a systematic underestimation of forest dis turbances. Here, we introduce FORMSpoT (Forest Mapping with SPOT Time series), a decade-long (2014-2024), country-scale mapping of forest canopy height at 1.5 m resolution over France, together with FORMSpoT-Delta, annual disturbance polygons derived from height differences in the FORMSpoT time series. Canopy heights were derived from annual SPOT-6/7 composites using a hierarchical transformer model (PVTv2) trained on high-resolution airborne laser scanning (ALS) data. To enable robust change detection, we developed a post-processing pipeline combining co-registration and spatio-temporal total variation denoising. We find that (1) the French disturbance regime is dominated by small events. Sub-100 m2 disturbances alone represent 72% of all events, and disturbances below 0.1 ha account for 97% of events and 39% of the disturbed area. These events are largely missed by Sentinel-1/2 and Landsat-based products. (2) Validated against succes sive ALS revisits across 19 sites and 5087 NFI plot revisits, FORMSpoT-Delta provides reliable detection (F1 > 0.8) above 100 m2 while retaining sensitivity to finer events that coarser products do not capture. (3) At the national scale, FORMSpoT-Delta resolves contrasted disturbance regimes, from clear-cut-dominated dynamics in maritime pine plantations to diffuse, smaller disturbance events in mountain forests, and captures their temporal dynamics, including the salvage-logging signature of the 2017-2022 bark beetle crisis in northeastern France.
ano.nymous@ccsd.cnrs.fr.invalid (Martin Schwartz) 30 Aug 2026
https://hal.science/hal-05731617v1
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[hal-05711066] Do intra-forest meadows influence browsing pressure on tree seedlings? A case study on silver fir, spruce and beech
Expanding populations of large herbivores compromise tree regeneration in many Northern Hemisphere forests. Browsing pressure vary spatially as large herbivores forage through the landscape, according to food availability. Intra-forest meadows attract red deer (Cervus elaphus L.) as they offer substantial food resources. However, the effect of intra-forest meadows on seedling browsing remains unexplored. Using a dataset of seedlings abundance and browsing observation from 2006 to 2024 in a study area of North-Eastern France, we modelled the browsing probability of silver fir (Abies alba Mill.), Norway spruce (Picea abies (L.) H. Karst), and beech (Fagus sylvatica L.) seedlings according to the distance to intra-forest meadows. We compared the current browsing level to simulated levels where seedlings would be distant from intra-forest meadows. We considered whether species availability, bramble availability, red deer abundance index, and forest fruits abundance index could influence the browsing of seedlings. We did not identify an effect of intra-forest meadows on the browsing probability of Norway spruce and beech. The proximity to intra-forest meadows reduced silver fir browsing probability when silver fir cover on the plot did not exceed 12.5% and when forest fruits were abundant on the study site. The browsing probability of silver fir was minimal at a distance of about 366 m (CI95% = 249 - 434 m) from intraforest meadows. The results of this case study indicate that proximity to intra-forest meadows could influence some tree species browsing intensity and spatial distribution but it does not consistently lower browsing pressure on forest regeneration.
ano.nymous@ccsd.cnrs.fr.invalid (Anthony Bled) 04 Aug 2026
https://ofb.hal.science/hal-05711066v1
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[hal-05774549] La demande d'assurance contre les aléas naturels des propriétaires forestiers français
Dans un contexte où les forêts françaises sont de plus en plus menacées par les aléas naturels, l’assurance forestière constitue un outil d’adaptation pertinent. Le taux d'adoption d'assurance est très faible en France. La compréhension de ces différences est une condition préalable à l’efficacité de l’assurance sur le marché privé. Nous identifions les déterminants de la demande d’assurance des propriétaires forestiers privés en faisant varier les caractéristiques des contrats d’assurance. À cette fin, nous mettons en œuvre une expérience de choix discret (Discrete Choice Experiment) avec, comme attributs, les aléas couverts, la durée du contrat, le niveau de franchise et le coût. Notre échantillon est composé de plus de 350 réponses fournies par des propriétaires forestiers privés en France métropolitaine. Au niveau global, tous les attributs des contrats influencent de manière significative les préférences en matière d’assurance. Les personnes interrogées privilégient généralement une couverture multirisque plus large, bien que leurs préférences dépendent de la combinaison spécifique des risques couverts ; par ailleurs, des franchises et des primes plus élevées réduisent la demande. Ces recherches permettent d'ouvrir à des pistes d'innovation pour le secteur assurantiel, notamment via l’assurance multirisque ou paramétrique.
ano.nymous@ccsd.cnrs.fr.invalid (Fanny Claise) 01 Oct 2026
https://hal.science/hal-05774549v1
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[hal-05849318] Promote the sharing, accessibility and digital use of temperate and tropical forests socio-ecosystems data
The PEPR-FORESTT (Priority Research Programme and Equipment) is a French interdisciplinary research programme focusing on the socio-ecological transition of forest systems in temperate and tropical regions. This programme forms part of the 'France 2030' national investment plan (40 M€ - 2024/2030), brings together the entire French scientific community to address four key challenges: (1) the societal challenges associated with the socio-ecological transition of forests, (2) the development of an agile bioeconomy based on wood, (3) the adaptation and resilience of forest ecosystems in the face of the effects of global change, and (4) the use of monitoring systems to foster scientific discoveries and guide forest management and policy decisions. https://www.pepr-forestt.org/eng FORESTT has taken an innovative approach by launching the NUM-DATA project. NUM-DATA addresses a cross-cutting need in the field of data and digital services by providing support to the programme's 15 scientific projects. NUM-DATA aims to bring together communities of practice in the fields of environmental sciences, social sciences and technology in order to tackle challenges associated with digital approaches and open science, thereby maximising their impact on forest resilience. NUM-DATA is structured around five areas: governance, FAIR practices, interoperability and data sharing, data science and digital commons. Expected outcomes include capacity building (use cases, reference frameworks, FAIR guidelines, etc.) in partnership with French national research organisations. (https://www.pepr-forestt.org/eng/projects/num-data).
ano.nymous@ccsd.cnrs.fr.invalid (Sophie Fortuno) 03 Nov 2026
https://hal.science/hal-05849318v1
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[hal-05849316] Building cooperation on FAIR data and digital services to strengthen research on temperate and tropical forests resilience
PEPR-FORESTT is a priority French interdisciplinary research programme, part of the 'France 2030' national investment plan (€40 million, 2024-2030), focusing on the transition of forest socio-ecosystems in temperate and tropical regions. Aimed at supporting research, the NUM-DATA project addresses a cross-cutting need in the field of data and digital services, providing support for the programme's 15 scientific projects. The NUM-DATA project team consists of IT engineers and research engineers from the research units of FORESTT's partner research performing organizations. The team favours a bottom-up approach and is working specifically on four targeted scientific projects within the framework of the programme: REGE-ADAPT: Forest regeneration and the adaptation and resilience of forest socio-ecosystems to climate change X-RISKS: Analysis and management of multiple risks in forest socio-ecological systems MONITOR: Intelligent ecological monitoring systems for forests FORESTT-HUB: Integration and training hub. This poster presents the ongoing deliverables of WP2: Support for project activities: FAIR data and services: (1) Scientific fields and overview of digital and data communities of practice in forest socio-ecosystems (environment, biodiversity, social sciences, forestry living labs, remote sensing, modelling, AI, etc.) (2) Capacity building: portfolio of digital services, adoption of (inter)national digital and thematic research infrastructures, vocabulary repositories, interoperability. (3) FAIR guidelines for FORESTT research, based on the Research Data Policy Framework of the RDA's 'Data Policy' Interest Group.
ano.nymous@ccsd.cnrs.fr.invalid (Chloe Barthalon) 03 Nov 2026
https://hal.science/hal-05849316v1
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[hal-05820956] ORCHIDEE X-RISKS (Work package 3, Task 3.3, PEPR FORESTT)
Climate change is already increasing the frequency and intensity of wildfires, windstorms, and bark beetle outbreaks, which have become major drivers of forest mortality. However, the future trajectories of these disturbances remain uncertain, particularly due to their potential interactions. Recent developments aim to incorporate mechanistic representations of natural disturbances into Land Surface Models (LSMs), the terrestrial components of Earth System Models (ESMs) used to project future climate trajectories. These models can represent both the effects of climate on ecosystems and disturbances, as well as feedbacks from the terrestrial biosphere to the atmosphere. The ORCHIDEE X-RISKS model now incorporates several forest mortality processes associated with wildfires, windstorms, and bark beetle outbreaks, with the aim of replacing empirical approaches with mechanistic representations of mortality processes. Disturbance interactions are accounted for through an emerging approach: rather than explicitly prescribing disturbance cascades, the model represents shared state variables and fluxes based on ecological processes. This poster presents the different disturbance modules developed in ORCHIDEE X-RISKS and evaluates their performance over the historical period through comparisons with observational data.
ano.nymous@ccsd.cnrs.fr.invalid (Émeline Chaste) 20 Oct 2026
https://hal.science/hal-05820956v1
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[hal-05780323] Climate and ungulate interactions in forest regeneration risk: a Bayesian network approach
Forest regeneration is a key process underlying forest resilience and future ecosystem functioning. However, regeneration patterns result from the interplay between multiple environmental pressures, including climate variability and ungulate disturbance. Using National Forest Inventory (NFI) data collected in 2023-2024 on forest regeneration and ungulate browsing pressure, we used Bayesian networks to investigate conditional associations between spring climate, regeneration, and ungulate-related disturbances across 10,123 forest sampling plots in France. Climate influences water availability and growing conditions, while browsing, rubbing, and rooting may affect regeneration. This approach provides an integrated framework for characterising complex interactions and identifying combinations of conditions associated with regeneration patterns.
ano.nymous@ccsd.cnrs.fr.invalid (Edwige Bellier) 06 Oct 2026
https://hal.science/hal-05780323v1
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[hal-05774615] La Réunion: 30 ans de suivi de la dynamique de la forêt tropicale humide
Un programme de suivi écologique à long terme a été lancé en 1990 dans la forêt de Mare-Longue, au sud-est de La Réunion (Océan Indien). Cette forêt est un vestige de la forêt tropicale humide de basse altitude de l'île. Elle s'est installée sur une coulée basaltique vieille d'environ 500 ans, où les sols sont très contraignants, et sa flore est d'une richesse exceptionnelle. Le dispositif compte trois parcelles permanentes d'un hectare (MALO 1, 2 et 3), installées entre 1990 et 2003 selon les protocoles standardisés d'inventaire forestier tropical. Tous les arbres de plus de 8 cm de DHP (1 cm depuis 2005) y ont été marqués, cartographiés et identifiés. Leur croissance, leur mortalité et leur recrutement sont suivis depuis plus de 30 ans, au cours de 17 campagnes d'inventaire dont la dernière date de 2026. C'est l'un des plus longs suivis forestiers continus du sud-ouest de l'océan Indien. La base de données porte sur plus de 17 000 arbres, soit 73 espèces ligneuses réparties en 36 familles. Les espèces endémiques dominent : 49 % des individus sont endémiques de La Réunion, 30 % des Mascareignes et 17 % sont indigènes. Les espèces exotiques ne représentent que 4 % des individus. Les diamètres vont de 0,36 à 156 cm, mais 74 % des tiges mesurent moins de 10 cm, ce qui reflète une forêt de petits arbres sur sols superficiels. Le jeu de donnée offre une base solide pour étudier la dynamique forestière via la composition, la croissance et la démographie.
ano.nymous@ccsd.cnrs.fr.invalid (Antoine, Becker-Scarpitta) 01 Oct 2026
https://hal.science/hal-05774615v1
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[hal-05770327] Les forêts et les incendies dans les Landes de Gascogne : Cahier scientifique et technique à destination des décideurs, gestionnaires et citoyens
Les forêts et les incendies dans les Landes de Gascogne : Cahier scientifique et technique à destination des décideurs, gestionnaires et citoyens.
ano.nymous@ccsd.cnrs.fr.invalid (Céline Meredieu) 30 Sep 2026
https://hal.inrae.fr/hal-05770327v1
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[hal-05774023] Modèle de la crise scolyte, arbre par arbre, sous changement climatique
Entre 2018 et 2021, une crise sans précédent a entraîné la destruction de 360 millions de mètres cubes d'épicéas par le scolyte typographe en Europe centrale, touchant également fortement la France (Grand Est, Bourgogne-Franche-Comté, Auvergne-Rhône-Alpes, Normandie). Le changement climatique, par la multiplication des sécheresses et des épisodes de chaleur, agit comme un double facteur en affaiblissant les capacités de défense des arbres et en accélérant le cycle de développement des scolytes. Ce travail présente un modèle à base d'agents développé sous NetLogo qui simule cette dynamique à l'échelle de l'individu (chaque arbre et chaque scolyte), sur une grille spatiale. Le modèle intègre des projections climatiques locales de 1850 à 2100, et met en relation la croissance et la vigueur des arbres avec la phénologie et la dynamique d'attaque coopérative des insectes. Les résultats montrent que les règles individuelles permettent l'émergence de dynamiques complexes à grande échelle, le modèle reproduit la propagation spatiale des foyers de scolytes d'arbre en arbre. De plus, de manière non calibrée, le modèle parvient à simuler un pic de population qui coïncide temporellement avec la crise réelle observée en Europe. Pensé comme un pont interdisciplinaire entre l'écologie, l'économie et l'aide à la décision (dans le cadre du projet X-RISKS), ce modèle est en cours d'enrichissement pour intégrer un agent "gestionnaire" simulant la décision humaine et un bilan hydrique fin.
ano.nymous@ccsd.cnrs.fr.invalid (Feras Kaokash) 01 Oct 2026
https://hal.science/hal-05774023v1
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[hal-05774021] Coping with extreme weather events across space and time: a case study from the French forest sector under windstorm
Extreme weather events increasingly challenge forest ecosystems, requiring effective post-crisis interventions. Coping strategies for supply shocks in the forest sector typically rely either on temporal adjustments, such as storage to smooth supply disruptions, or on spatial reallocations, such as transport subsidies to redistribute supply. This study compares these two approaches by simulating crisis wood storage and transport subsidies following a large-scale windstorm affecting French forests. Using the French Forest Sector Model (FFSM), a bioeconomic partial equilibrium framework, we simulate sectoral and carbon sink responses across spatial and temporal scales, and develop a social welfare indicator integrating producer and consumer surplus, policy costs, and carbon externalities. Results reveal trade-offs. Storage stabilizes prices and keeps them higher, at the expense of producer and consumer surplus, but increases overall social welfare through better preservation of the forest carbon sink and greater spatial equity: it reduces transfers toward less affected regions and benefits more severely windstorm-impacted regions. Transport subsidies increase wood mobilization as well as producer and consumer surplus, but perform worse in terms of social welfare gains, and tend to favor regions spared by the windstorm at the expense of those that would need support the most. These contrasting regional patterns highlight how each policy redistributes the burden of the shock across territories, with storage promoting convergence and transport subsidies reinforcing pre-existing disparities. Trade-offs thus arise between market performance and carbon sink preservation, between spatial scales of intervention, and between short- and long-term temporal considerations, offering policy-relevant insights for future forest crisis management.
ano.nymous@ccsd.cnrs.fr.invalid (Killian Baué) 01 Oct 2026
https://hal.science/hal-05774021v1
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[hal-05782818] Éclaircir pour maintenir la fonction de protection ?
En montagne, certaines forêts peuvent protéger les infrastructures contre les chutes de blocs, une capacité qui dépend de la structure des peuplements. L'opportunité d'intervenir dans ces forêts de protection fait débat. Ce travail cherche à identifier des sylvicultures offrant un compromis durable entre protection et régénération. Pour cela, nous adoptons une approche couplant simulation de la dynamique forestière et simulation de la propagation de blocs, appliquée à des peuplements virtuels construits sur les données de l'Inventaire Forestier National.
ano.nymous@ccsd.cnrs.fr.invalid (Eliot Perrin) 07 Oct 2026
https://hal.science/hal-05782818v1
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[hal-05762273] Altered fire regimes and biodiversity in New Caledonia
<div><p>Remote tropical Pacific Islands evolved in long isolation, giving rise to exceptionally unique biodiversity. Beginning with Austronesian settlement in recent millennia and followed by European colonisation in recent centuries, human arrival has profoundly affected these systems, including altered fire regimes. Among these islands, New Caledonia stands out as one of the few tropical archipelagos recognised as a biodiversity hotspot in its own right, harbouring the world's highest density of endemic species, including more than 2600 vascular plant species and over 135 lizard species. Wildfires have long been identified as a major threat to this biodiversity, yet fire regimes, their drivers, and their impacts on species remain poorly understood. Here, we synthesise current knowledge on fire regimes in New Caledonia, their impacts on biodiversity, and existing fire management policies. Increases in wildfire frequency and extent since human arrival have contributed to widespread degradation of native ecosystems, favouring more pyrophytic vegetation and threatening hundreds of species with extinction. Current management strategies, largely focused on fire bans and emergency response, have proven insufficient to safeguard biodiversity. While strengthening firefighting capacity remains necessary, there is an urgent need to transition toward a more integrated and strategic approach to fire management. Such an approach should be tailored to New Caledonia's diverse socioecological contexts, incorporating traditional fire practices where appropriate and accounting for variability across ecosystems and land-tenure systems. Improved fire monitoring, a better understanding of species-specific vulnerabilities, and inclusive stakeholder engagement are essential to mitigate biodiversity loss and enhance ecosystem resilience under ongoing global change.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Thomas Ibanez) 24 Sep 2026
https://hal.inrae.fr/hal-05762273v1
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[hal-05742838] Developping ecoacoustic tools to detect, identify and monitor soil biodiversity
<div><p>Background sound is well distinguished from earthwormsRBackground sound is well distinguished from earthworms</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Nathanaël Almeida-Streveler) 08 Sep 2026
https://hal.science/hal-05742838v1
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[hal-05727590] Holocene vegetation change and fire–plant diversity shifts in Mediterranean France
Changes in fire activity are recognized as a major threat to biodiversity and vegetation communities across the Mediterranean Basin. However, long‐term fire–vegetation interactions remain poorly investigated. Here, we combine a high‐resolution charcoal record with pollen data from the “ Étang des Aulnes ” lake (southern France) to reconstruct the last ~8000 years of fire dynamics and assess its influence on vegetation communities and diversity. A significant result is that the highest level of fire frequency and burned biomass occurred around 4200 cal a BP , coinciding with the decline of deciduous oak forests and their replacement by evergreen oak forests/scrublands. Moreover, the relationship between taxonomic richness and burned biomass is assessed and shows that taxonomic richness reaches its maximum at intermediate burned biomass levels. We discuss here how fire may explain this relationship, as well as its limitations, which are influenced by variations in environmental and land‐use conditions. Together, these findings illustrate how long‐term fire dynamics influence vegetation diversity and community trajectories and highlight the structuring role of interacting drivers, such as fire, herbivory, and anthropogenic activities, in Mediterranean ecosystems.
ano.nymous@ccsd.cnrs.fr.invalid (Cécile Latapy) 28 Aug 2026
https://hal.science/hal-05727590v1
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[hal-05718677] In Situ GWAS in Two Range‐Edge Populations of European Beech ( Fagus sylvatica L.) Identify Genetic Factors of Adaptation to Climate Change
In forest tree populations, the timing of budbreak (TBB) depends on several factors, both environmental and genetic. The genomic architecture underlying this trait is still not fully characterized. So far, common garden experiments have highlighted a few genomic regions with little heritability, while the whole spectrum of TBB variation observed in the wild still remains unexplored. We performed an in situ genome‐wide association study (GWAS) to investigate the genetic and environmental bases of phenotypic variation in budbreak in two wild range‐edge populations of the temperate continental tree, European beech ( Fagus sylvatica L.) surveyed in two consecutive years. We found distinct significant loci between populations and among years, suggesting that local adaptation has occurred and that genotype‐by‐environment interactions contribute to the observed variation. The phenotypic variance explained by the significant loci is between 0.2% and 54% for field data and 0% to 59% for modelled data, which suggests that while some traits are polygenic, some others are influenced by a few loci with large effects in the population, which demonstrates the relevance of conducting in situ GWAS in multiple populations. Our findings provide novel insights into the complex genetic architecture of TBB in forest trees. The genetic diversity of budbreak control provides opportunities for selection that could be used through assisted migration to help prepare beech forests to face climate change.
ano.nymous@ccsd.cnrs.fr.invalid (Lauren Clément) 17 Aug 2026
https://hal.inrae.fr/hal-05718677v1
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[hal-05713108] Public DNA archives reveal pervasive cryptic structure and taxonomic confusion in bark and ambrosia beetles (Curculionidae: Platypodinae and Scolytinae)
Public DNA archives support large-scale biodiversity assessment, yet are constrained by taxonomic misidentifications and unrecognized cryptic structure. The challenge is especially acute in hyperdiverse, economically important groups like bark and ambrosia beetles, where morphological conservatism can conceal deep genetic divergence. We applied an investigative data-mining framework to full publicly available GenBank COI sequences for this clade at the time of download, initially retrieving 8,899 sequences from more than 1,000 species. After quality filtering and replication criteria, 3,650 sequences representing 75 species were retained for analysis. Under assemble species by automatic partitioning (ASAP), all 75 species − 100% - contained multiple barcode partitions. However, divergence depth and pattern varied widely. Under a conservative criterion of p-distance, 26 species were flagged as candidate species complexes, and all the remaining ones exhibited continuous structure or fine-scale partitioning of shallow divergences between populations. Concordance delimitation indicated that these patterns are not method artefacts. While cryptic divergence is ubiquitous among scolytines, it has arisen via at least four evolutionary mechanisms, which we demonstrate using case studies. Deeply divergent geographical COI lineages suggesting cryptic complexes are demonstrated with Xyleborus ferrugineus (Fabricius). By contrast, shallow population structure rather than distinct lineages is shown with Tomicus piniperda (Linnaeus) which exhibited high haplotype diversity but minimal inter- MOTU divergence. A taxonomic name–sequence mismatch is exemplified with Ambrosiodmus rubricollis (Eichhoff) which comprised several deeply divergent Asian COI lineages, one of which has spread across Europe and North America. Lastly, a sharp split between European and North American lineages whose taxonomy remains unresolved is shown with Dryocoetes autographus (Ratzeburg). Our findings show that critically analyzed public barcodes can flag cryptic complexes (not formal species delimitation) from shallow structure and clarify the identities of globally significant invasive species. This approach – starting with all available sequences rather than hand-picked groups – provides a scalable framework to use large, uncurated genetic repositories and highlights the need for integrative taxonomy.
ano.nymous@ccsd.cnrs.fr.invalid (Yiyi Dong) 07 Aug 2026
https://hal.inrae.fr/hal-05713108v1
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[hal-05749890] European beech reproduction is not reduced by drought, including the 2003, 2018, and 2022 extremes
Climate change is intensifying drought stress in temperate forests, but its effects on tree reproduction, central to forest regeneration and migration capability, remain poorly understood. Here, we analyze 221 time series of beech ( Fagus sylvatica ) seed production across Europe to test whether drought reduces seed output. We isolate drought exposure during the flowering, pollination, and seed maturation phases of reproduction, and test for legacy effects on future reproduction. Seed production was not impaired by summer drought, and dry spring conditions were associated with increased output, likely via enhanced pollen dispersal. Thus, once initiated, beech reproduction is not reduced by drought, with no suppression of reproduction the following year. Reproduction was not reduced at the driest sites during exceptional European summer droughts in 2003, 2018, and 2022. Considered alongside prior evidence that drought suppresses forest growth and elevates mortality, these findings indicate that vital rates can respond in opposite directions to the same stressor. Such contrasts may sustain forest reproduction during heat–drought events yet shift demographic balance toward higher mortality and turnover as climatic extremes intensify.
ano.nymous@ccsd.cnrs.fr.invalid (Jakub Szymkowiak) 21 Oct 2026
https://hal.science/hal-05749890v1
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[hal-05838431] Predicting spatio-temporal wildfire propagation with dynamic firebreaks
<div><p>Wildfire management strategies increasingly demand accurate predictive models that integrate real-time intervention measures. Despite advances in machine learning (ML) for wildfire modelling, existing approaches largely overlook the role of firebreak placement. In this work, we present the first deep learning-based predictive model for simulating spatio-temporal wildfire propagation with dynamic firebreaks. Utilizing a Convolutional Long Short-Term Memory (ConvLSTM) architecture, the model captures both the spatial and temporal complexities of wildfire spread while incorporating data on firebreak positioning and effectiveness. Our training dataset, derived from Cellular Automata (CA) simulations, integrates key geophysical parameters and human intervention strategies, including temporary and permanent firebreaks. Model validation across three major wildfire events in California demonstrates robust performance, with significant accuracy gains in scenarios involving strategic firebreak placement. This integration of movable firebreak placement into a wildfire spread model provides a tool for improving real-time wildfire management efforts.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Jiahe Zheng) 25 Oct 2026
https://hal.science/hal-05838431v1
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[hal-05662107] Sylv’Agora, un jeu de négociation pour apprendre les enjeux de gestion forestière
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ano.nymous@ccsd.cnrs.fr.invalid (Charlotte Michel) 18 Jun 2026
https://hal.science/hal-05662107v1
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[hal-05666076] Ressources forestières, projets bioéconomiques et éthique environnementale : aux sources des représentations de la forêt
L'objectif de la communication est de donner un aperçu des contributions méthodologiques et des résultats d'une recherche doctorale en cours. Elle interroge les enjeux de représentations autour des peuplements forestiers dans le département des Pyrénées-Atlantiques (P-A), dans un contexte de changements globaux, de transitions (environnementale et énergétique) et de déploiement de projets bioéconomiques (Pahun et al., 2018). Du fait de la complexité des relations entre les acteurs et la forêt, du caractère équivoque de la transition, de la pluralité, diversité et de l'hétérogénéité des profils et de la question du multi-usages, c’est par le prisme notionnel de l’ « éthique environnementale » (ÉE) (Baard et Ahteensuu, 2019) que sont abordés les enjeux de la recherche. En effet, il s’agit de questionner les différents modes d’interventions que privilégient les acteurs dans les peuplements, les valeurs associées à la forêt et sous-tendant leurs actions, et les arguments qu’ils mobilisent pour justifier le bien-fondé de leurs pratiques (Cf. Illustration ci-contre). Le développement d'initiatives en faveur de la bioéconomie forestière – fondées sur des bioressources forestières, biomasse, bioénergies, biotechnologies, (co)produits sylvicoles et forestiers -, avec deux potentielles implantations de projets à l’échelle des P-A, fait entrer en collision différents référentiels d’ÉE, comme l'illustrent les récits alternatifs, voire contre-récits de la lecture bioéconomique des rapports entre la société et le vivant (Petit et al., 2025). À rebours d’une focalisation sur la question de la ressource, nous cherchons à remonter aux sources mentales et matérielles qui expliquent le(s) regard(s) que portent les protagonistes des P-A sur la forêt et les logiques opérationnelles sous-jacentes. Dans une lecture renouvelée et symbolique, nous nous demandons schématiquement qui incarnent, sur le terrain des P-A, nos John Muir et nos Gifford Pinchot, qui ont animé les débats de la gestion forestière et le rôle de ces espaces dans la société (Clayton, 2020)
ano.nymous@ccsd.cnrs.fr.invalid (Magali Iriart) 23 Jun 2026
https://hal.science/hal-05666076v1
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[hal-05643880] Perception of (multi)risk in forest: Bibliometric analysis of the literature
Climate change is increasing the frequency and interactions of natural disturbances affecting forests, leading to complex multirisk situations. Understanding how these risks are perceived by stakeholders is becoming increasingly important for sustainable forest management and adaptation strategies. In this context, this bibliometric analysis complements a systematic literature review on forest risk perception by providing an overview of the structure and evolution of the scientific literature, including publication trends, influential authors, countries, and thematic research clusters.
ano.nymous@ccsd.cnrs.fr.invalid (Clémence Barrey) 04 Jun 2026
https://hal.science/hal-05643880v1
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[hal-05688700] Sylv’Agora : Version simplifiée à jouer avec des professionnels
Sylv’Agora est un jeu de rôle qui vise à simuler des négociations d’acteurs sociaux à propos de décisions à prendre sur la gestion d’une forêt fictive. Cette version du jeu permet de jouer rapidement (3h) entre professionnels de la gestion forestière ou avec des élus. Le jeu comprend 9 acteurs représentatifs de la gestion forestière, des usages de la forêt et du territoire. Il est contextualisé à une forêt de type pyrénéen. Chaque personnage a des objectifs à atteindre : achat de bois, mise en conservation écologique de parcelles, droits de pêche et de chasse, maintien des emplois locaux, accès aux espaces, etc. La prise de décision collective porte sur des orientations de gestion d'un socio-écosystème forestier : extension de la réserve actuelle, planification forestière sous la forme de choix sylvicoles, aménagement touristique (parkings, routes). A la fin des négociations, les arbitres veulent s’assurer d’avoir une majorité de « oui » pour le projet retenu de réserve pour éviter les conflits entre acteurs.
ano.nymous@ccsd.cnrs.fr.invalid (Charlotte Michel) 10 Jul 2026
https://hal.science/hal-05688700v1
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[hal-05666131] Forêt, changement climatique : quelle gestion des forêts dans les Pyrénées-Atlantiques ?
Le changement climatique et les objectifs de transition environnementale, placent la forêt au centre de multiples enjeux : les besoins en bois pour la construction, la préservation de la biodiversité forestière et des services rendus à la société, le développement d’emplois locaux, etc. Cependant, différentes visions apparaissent, concernant la façon de se représenter les peuplements et les modes d’intervention à privilégier. Comment les acteurs impliqués dans le domaine, à l’échelle du département des Pyrénées-Atlantiques, incarnent-ils ces aspects ? Les chemins qu’empruntent les acteurs sont pluriels et les incertitudes les poussent à sortir des sentiers battus.
ano.nymous@ccsd.cnrs.fr.invalid (Magali Iriart) 23 Jun 2026
https://hal.science/hal-05666131v1
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[hal-05624856] From Traps to Taxa: Building a Robust DNA Barcode Reference Library for the Early Detection of Invasive Cerambycidae
Accurate and rapid identification of insect species is essential for effective biosurveillance, especially with increasing global trade and the spread of invasive pests. DNA barcoding has become a powerful tool for specimen identification, but its reliability depends heavily on the completeness and accuracy of reference databases. Many existing databases remain fragmentary and contain poorly annotated or misidentified records. Here, we present a curated DNA barcode reference library of 4097 DNA barcodes representing 169 species of longhorned beetles (Coleoptera: Cerambycidae), a group frequently intercepted in European biosurveillance programmes using multi‐pheromone traps. By prioritizing taxonomic validation and data quality, this library provides a robust resource for accurate specimen identification. Beyond biosurveillance, it also supports ecological research, as cerambycids are valuable bioindicators of forest health. Our results highlight the critical role of expert curation in ensuring the accuracy of barcode libraries used for both pest monitoring and biodiversity assessment.
ano.nymous@ccsd.cnrs.fr.invalid (Loïs Veillat) 18 May 2026
https://hal.science/hal-05624856v1
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[hal-05550608] No seed size–number trade-off in European beech: climate governs investment per seed
Mast-seeding trees can vary seed output by orders of magnitude among years, but it remains unclear whether high seed production comes at the cost of reduced per-seed investment, as predicted by fixed-budget allocation models. We quantified individual seed production with seed mass in European beech across 2,792 trees and 123 populations spanning the species’ European range and quantified seed protein and lipid content in a subset of 35 populations. Seed mass showed a positive association with seed production, with seeds from high-seeding years being 14% heavier than those from low-seeding years, providing no evidence for a seed size–number trade-off and instead supporting variable reproductive allocation. In contrast, seed protein content decreased by 31% with increasing seed production, whereas lipid content increased (by 14%), indicating that nitrogen becomes constraining at high reproductive output while carbon-based provisioning is maintained. Climate further structured provisioning: seed mass and protein content were the lowest at climatic range margins, being 28% and 32% lower, respectively, than at the center of the climatic range. Together, these results show that European beech can increase seed output without reducing per-seed biomass, but that nitrogen limitation emerges under high seed production and that climatic constraints reduce both seed size and protein content toward range edges. This identifies a pathway that may strengthen regeneration bottlenecks at both trailing and leading margins, especially as climate warming intensifies.
ano.nymous@ccsd.cnrs.fr.invalid (Katarzyna Kondrat) 13 Mar 2026
https://hal.science/hal-05550608v1
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[hal-05550623] Forest fecundity declines as climate shifts
Tree fecundity underpins regeneration, range tracking, and seed supply for assisted migration, yet may decline as climates move beyond reproductive niches. Using 34 years of nationwide harvest records from Poland (40,530 observations across 438 forest districts) for five dominant taxa — oaks (Quercus robur, Q. petraea), European beech (Fagus sylvatica), Scots pine (Pinus sylvestris), and silver fir (Abies alba) — we tested whether sustained climate change has reduced fecundity after accounting for seed demand. Mean viable seed production declined by 32–65% across species (oaks ~65%, pine ~64%, fir ~44%, beech ~32%). Summer warming was the dominant driver, with hotter summers reducing seed output across all species. Growing-season moisture and spring temperature contributed little to long-term trends, although they shaped local responses. Weather effects varied with background climate, indicating divergence between short-term (within-site, transient) and long-term (across-site, equilibrium) sensitivities. This modulation by local climate indicates substantial capacity for local adaptation or acclimation, offering actionable leverage for management. Together, our results show fecundity declines consistent with warming, pushing populations beyond reproductive climatic niches, but also identify potential to mitigate risk by aligning provenance choice and assisted migration with projected site climates.
ano.nymous@ccsd.cnrs.fr.invalid (Jessie Foest) 13 Mar 2026
https://hal.science/hal-05550623v1
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[hal-05550617] European beech reproduction is resilient to drought, including the 2003, 2018, and 2022 extremes
Climate change is intensifying drought stress in temperate forests, but its effects on tree reproduction, central to forest regeneration and migration capability, remain poorly understood. In mast-seeding species such as European beech (\textit{Fagus sylvatica}), reproduction is regulated by temperature cues rather than current-year resource availability, raising questions about drought sensitivity once reproduction is triggered. Here, we analyse 221 time series of beech seed production across Europe to test whether drought, after reproduction has been initiated, reduces seed output. We isolate drought exposure during pollination and seed maturation phases, including severe events in 2003, 2018, and 2022. Seed production was not impaired by summer drought, and dry spring conditions were associated with increased output, likely via enhanced pollen dispersal. Thus, once triggered, beech reproduction is not reduced by drought. Considered alongside prior evidence that drought suppresses growth and elevates mortality, these findings indicate that vital rates can respond in opposite directions to the same stressor—reproduction is buffered while growth and survival decline. Such contrasts may sustain short-term regeneration during heat–drought events yet shift demographic balance toward higher mortality and turnover as climatic extremes intensify.
ano.nymous@ccsd.cnrs.fr.invalid (Jakub Szymkowiak) 13 Mar 2026
https://hal.science/hal-05550617v1
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[hal-05492693] Promoting oak (Quercus pubescens Willd.) seedling development: finding the balance between canopy opening and grass competition under water stress
To adapt Mediterranean forests to increasingly harsh climatic conditions by promoting genetic diversity, thinning is often considered an effective strategy to enhance sexual regeneration. However, determining an optimal thinning level that both increases light availability and maintains favorable microclimatic conditions for germination, without excessively promoting herbaceous competition, remains challenging. To better understand how abiotic and biotic factors influence oak seedling development and to help identify a balanced thinning level under climate change, we conducted a semi-controlled experiment testing the combined effects of competition with a grass species (Poaceae), two canopy opening levels, and water stress. Our results highlight the crucial role of competition with Poaceae species - in our case Festuca ovina - in oak regeneration. Their presence not only intensifies competition for essential resources, but also modifies soil properties and alters belowground interactions, overall creating conditions less favorable for oak seedling establishment. In addition, our results highlight the significant impact of key abiotic factors that are canopy opening (which influences light availability) and hydric conditions, as well as their interactions with the effects of competition. We observed a consistent need for adequate light to ensure optimal seedling performance, suggesting that successful regeneration depends on balancing sufficient canopy opening to improve light availability with maintaining sufficient cover to mitigate water stress and limit grass competition. Overall, our study contributes to the broader debate on sustainable forest management strategies under changing climatic conditions.
ano.nymous@ccsd.cnrs.fr.invalid (Solène Brasseur) 04 Feb 2026
https://hal.science/hal-05492693v1
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[hal-05688844] Sylv'Agora : Version landaise
Sylv’Agora est un jeu de rôle qui vise à simuler des négociations d’acteurs sociaux à propos de décisions à prendre sur la gestion d’une forêt fictive. Cette version est une déclinaison du jeu adaptée au contexte forestier landais. Le jeu comprend 14 acteurs représentatifs de la gestion forestière, des usages de la forêt et du territoire. Chaque personnage a des objectifs à atteindre : mise en place d'une charte forestière, gestion forestière et production de bois, aménagements DFCI, restauration d'une lagune, etc. La prise de décision collective porte sur mise en place de la charte forestière. A la fin des négociations, les arbitres veulent s’assurer d’avoir une majorité de « oui » pour le projet retenu pour éviter les conflits entre acteurs.
ano.nymous@ccsd.cnrs.fr.invalid (Maxence Chanal) 10 Jul 2026
https://hal.science/hal-05688844v1
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[hal-05551787] Understanding the Heterogeneity of Forest Insurance Adoption: A Comparative Study of Insurance Mechanisms Between France and China
In a context of increasing natural hazards due to climate change, forest insurance is a relevant tool to consider. However, the development of forest insurance schemes varies widely across countries, reflecting differences in forest characteristics, institutional frameworks, and public risk management policies. In this article, we investigate the drivers of this heterogeneity by comparing forest insurance schemes in two contrasting national contexts: France and China. While forest insurance coverage remains relatively limited in France, China has implemented large-scale insurance programs. By examining the design, governance, and role of government intervention in both schemes, we identify the key factors that help explain the differences in insurance uptake across countries. Finally, we discuss innovative insurance products and policy mechanisms that could encourage the adoption of forest insurance.
ano.nymous@ccsd.cnrs.fr.invalid (Yafei Wang) 13 Mar 2026
https://agroparistech.hal.science/hal-05551787v1
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[hal-05467262] FORMSpoT: A Decade of Tree-Level, Country-Scale Forest Monitoring
The recent decline of the European forest carbon sink highlights the need for spatially explicit and frequently updated forest monitoring tools. Yet, existing satellite-based disturbance products remain too coarse to detect changes at the scale of individual trees, typically below 100 m². Here, we introduce FORMSpoT (Forest Mapping with SPOT Time series), a decade-long (2014-2024) nationwide mapping of forest canopy height at 1.5 m resolution, together with annual disturbance polygons (FORMSpoT-Δ) covering mainland France. Canopy heights were derived from annual SPOT-6/7 composites using a hierarchical transformer model (PVTv2) trained on high-resolution airborne laser scanning (ALS) data. To enable robust change detection across heterogeneous acquisitions, we developed a dedicated post-processing pipeline combining co-registration and spatio-temporal total variation denoising. Validation against ALS revisits across 19 sites and 5,087 National Forest Inventory plots shows that FORMSpoT-Δ substantially outperforms existing disturbance products. In mountainous forests, where disturbances are small and spatially fragmented, FORMSpoT-Δ achieves an F1-score of 0.44, representing an order of magnitude higher than existing benchmarks. By enabling tree-level monitoring of forest dynamics at national scale, FORMSpoT-Δ provides a unique tool to analyze management practices, detect early signals of forest decline, and better quantify carbon losses from subtle disturbances such as thinning or selective logging. These results underscore the critical importance of sustaining very high-resolution satellite missions like SPOT and open-data initiatives such as DINAMIS for monitoring forests under climate change.
ano.nymous@ccsd.cnrs.fr.invalid (Martin Schwartz) 20 Jan 2026
https://hal.science/hal-05467262v1
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[hal-05781608] Cartographier les multi-risques forestiers : quand perception, observation et prospective s'allient pour soutenir la gouvernance adaptative
Dans le cadre du projet Perforssa (PSGAR GRIFON &amp; PEPR FORESTT - X-RISKS), la méthode du Zonage À Dire d’Acteurs a été mise en œuvre dans les Landes de Gascogne afin d’identifier les perceptions spatialisées des risques multiples dans ce socio-écosystème forestier soumis à de nombreux aléas climatiques et enjeux socio-économiques. L’analyse des ~80 cartes produites a permis d’identifier les risques les plus fréquemment perçus, notamment les incendies, les tempêtes, les sécheresses, les inondations et l'érosion côtière. La comparaison des cartes de perception avec les données bioclimatiques associées permet d'identifier des zones d'action prioritaires. La prise en compte de ces résultats contribue à l’élaboration d’une gestion intégrée des risques.
ano.nymous@ccsd.cnrs.fr.invalid (Titouan Dubo-Degeilh) 13 Oct 2026
https://hal.science/hal-05781608v1
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[hal-05706552] Combining paleoecology and modeling to explore cascading disturbances in forest ecosystems
Climate-induced cascading disturbance interactions pose a major challenge to the sustainable provision of forest ecosystem services to society. Developing a deeper understanding and enhanced capacity to simulate these interactions is essential for identifying disturbance-induced tipping points in forest ecosystems, and for improving management in response to such changes. This forum paper highlights opportunities to anticipate future forest disturbance trajectories by integrating paleoecology and modeling. Recent advances in forest landscape models (FLMs) and in the paleoecology of disturbances provide novel opportunities for hindcast simulations that account for multiple interacting disturbances. FLM simulations informed by paleoecological reconstructions could be mutually beneficial for both the modeling and paleoecological research communities. This integrative approach would enable the testing of previously unexplored causal hypotheses to explain discrepancies between reconstructed and simulated vegetation trajectories, while also evaluating model performance across long temporal scales and under changing climatic conditions. To integrate paleoecological data into FLMs, priority should be given to multi-proxy paleoecological reconstructions across multiple forest ecosystems to generate the data needed to inform and refine models. These new research avenues may advance projections of ecosystem change, thereby strengthening the scientific basis for guiding adaptive forest policy and management.
ano.nymous@ccsd.cnrs.fr.invalid (Cécile C Remy) 29 Jul 2026
https://hal.science/hal-05706552v1
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[hal-05619369] Complementary Evidence From Historical and Contemporary Gene Dispersal Reveals Contrasting Population Dynamics in a Tropical Tree Species
Gene flow shapes the demographic stability and evolutionary potential of tropical forest trees, yet its dynamics may differ depending on the temporal scale at which it is assessed. We combined spatial genetic structure (SGS), parentage analyses, and reproductive success metrics to investigate historical and contemporary gene dispersal in four populations of Dicorynia guianensis across French Guiana, encompassing sites differing in environment and management history. A total of 1528 individuals were genotyped using 66 nuclear and 23 plastid microsatellite markers, enabling high-resolution inference of biparental and maternal gene dispersal. Historical mating and dispersal parameters inferred from SGS revealed marked contrasts among populations. Some populations exhibited high historical gene dispersal distances and weak spatial genetic structure, whereas others showed stronger SGS and long-term aggregative dispersal patterns. Contemporary parentage analyses further highlighted differences in seed and pollen dispersal distances, parent assignment rates, and reproductive skew. In certain populations, pronounced reproductive inequality and reduced effective connectivity were observed, while others displayed more balanced reproductive contributions. By jointly evaluating long-term dispersal legacies and present-day reproductive patterns, our study demonstrates the value of combining indirect and direct genetic approaches to assess population dynamics and conservation status in tropical forest trees. This multi-temporal perspective provides a comprehensive basis for long-term monitoring and sustainable management in heterogeneous tropical landscapes
ano.nymous@ccsd.cnrs.fr.invalid (Julien Bonnier) 11 May 2026
https://hal.science/hal-05619369v1
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[hal-05777905] Poster PEPR FORESTT - XRISKS : A dataset of mechanical traits of standing trees in Alpine protective forests
<div><p>A key element in quantifying the protective effect of forests against gravitational hazard is a thorough understanding of the mechanical properties of a standing tree. However, these data remain highly incomplete for mountain tree species, both for healthy trees and for trees affected by natural disturbances such as fire or pest attacks. To address this knowledge gap, we are developing an in-situ measurement dataset covering multiple mountain tree species and health conditions. This dataset aims to improve the characterization of tree mechanical properties and provide a robust basis for assessing the protective role of forests against gravitational hazards.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Sylvain Dupire) 05 Oct 2026
https://hal.science/hal-05777905v1
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[hal-05761921] Context-aware quantile baselines for disturbance detection in non-stationary short-rotation forest plantations
<div><p>Disturbances such as pests, diseases, fire, windthrow, and drought are increasingly affecting forests and require near-real-time monitoring from satellite observations. Existing near-real-time methods often detect anomalies relative to historical vegetation index (VI) baselines based on periodic, parametric, or autoregressive models, which can be difficult to apply in short-rotation plantations with strongly non-stationary canopy dynamics. We introduce the FOrest plantation Canopy ALert system (FOCAL), a monitoring framework designed for relatively homogeneous, intensively managed short-rotation plantations that combines pixel-level Quantile Regression Forest baseline prediction with rule-based detection of persistent negative anomalies. For each new Sentinel-2 acquisition, FOCAL first predicts the range of VI values expected under undisturbed conditions from stand age, management variables, environmental conditions, acquisition geometry, and recent VI observations. A disturbance alert is then issued when observed VI values fall below the lower bound of this predicted contextual range for consecutive acquisitions. FOCAL was evaluated using 118 Eucalyptus plantation stands in Brazil affected by confirmed disturbance events, 141 undisturbed reference stands, and a controlled mortality-patch experiment. Using NDVI, FOCAL achieved a mean class accuracy of 0.78 and a binary F1-score of 0.76, outperforming benchmark time-series methods. Detection was particularly strong for fire (100%) and severe water stress (84%), and mortality patches as small as 12 × 12 m were identified. These results demonstrate FOCAL's potential for disturbance detection in intensively managed Eucalyptus plantations.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Guerric Le Maire) 24 Sep 2026
https://hal.science/hal-05761921v1
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[hal-05471774] Feller Property and Absorption of Diffusions for Multi-Species Metacommunities
<div><p>We consider individuals of two species distributed over m patches, each with a hosting capacity \(d_i N\) , where \(d_i \in (0, 1]\). We assume that all the patches are linked by the dispersal of individuals. This work examines how the metacommunity evolves in these patches. The model incorporates Wright-Fisher intra-patch reproduction and a general exchange function representing dispersal. Under minimal assumptions, we demonstrate that as \(N\) approaches infinity, the processes converge to a diffusion process for which we establish the Feller property. We prove that the limiting process almost surely reaches the absorbing states in finite time.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Benoît Henry) 22 Jan 2026
https://hal.science/hal-05471774v1
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[hal-05732463] Paleo- and historical ecology contributions to baselines for restoration and reintroductions in central Chile
Central Chile, despite being a zone of conservation prioritization and threat, only benefits from limited ecological restoration and species reintroductions. We suggest that this is due to a lack of integration between ecology and historical ecology and paleo-ecology, and a consequent lack of baseline scenarios for public consideration. Here, we review the knowledge and knowledge gaps around the distributions, habitats, and ecological roles and interactions of a set of extant and extinct plant and animal species of conservation interest. We synthesize the current ecological understanding, which describes an accepted pre-Columbian ecological scenario, and we construct an alternative scenario based on the review and integration of paleo-ecological and historical sources. Both scenarios agree there has been significant land-cover change over the past 500 years, but disagree on pre-Columbian baselines. The accepted scenario proposes a species-poor primordial high forest without disturbance, evolving in isolation with static species distributions and realized niches, and recently threatened by invasive species. The alternative paleo-ecology-informed scenario proposes a frequently disturbed habitat mosaic whose community composition across time is dominated by long-distance dispersal, the Pleistocene-Holocene megafaunal extinctions, and changing species distributions and realized niches. We propose specific potential restoration baselines for the alternative scenario. Both scenarios can be the basis for hypotheses, restoration baselines, and novel environmental narratives.
ano.nymous@ccsd.cnrs.fr.invalid (Meredith Root-Bernstein) 31 Aug 2026
https://hal.science/hal-05732463v1
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[hal-05504167] Enhancing PROSAIL Inversion: Key Considerations and Practical Insights
Accurate estimation of plant biophysical properties is essential for understanding ecosystem functioning, monitoring forest health, productivity, and assessing the risk of disturbances. However, retrieval accuracy is often constrained by uncertainties in model parameterization, soil background effects, and spectral redundancy. This study systematically evaluates the influence of parameter range, band selection, and soil background on the inversion of leaf area index, chlorophyll content, leaf mass per area, and equivalent water thickness in Eucalyptus plantations throughout an entire growing season. Retrievals were conducted by inverting the PROSAIL model. Our approach led to three innovative findings: 1) the integration of trait-informed parameter ranges, tailored to Eucalyptus plantations, which substantially improves retrieval accuracy, especially for leaf mass per area; 2) the demonstration that band selection can reduce root mean square error by up 58% for Chlorophyll content, 52% leaf mass per area and 69% for equivalent water thickness; and 3) the performance of soil background datasets strongly depends on the sampling strategy used and whether band selection was applied. These findings highlight that combining spectral optimization with contextual prior knowledge provides a robust framework for improving PROSAIL inversion in forest ecosystems, advancing remote sensing applications for plantation monitoring and sustainable management of natural resources. Moreover, this work presents a rarely explored application of PROSAIL inversion to forest plantations, extending its use beyond crop studies.
ano.nymous@ccsd.cnrs.fr.invalid (Vitória Barbosa Ferreira) 10 Feb 2026
https://hal.inrae.fr/hal-05504167v1
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[hal-05403814] Long-term forest-line dynamics in the French Pyrenees: an accelerating upward shift related to forest context, global warming and pastoral abandonment
Worldwide, the upper forest line has climbed over the past decades, shaping mountain landscapes in response to global changes. In European mountains, this recent trend is a continuation of the forest transition initiated in the mid-19th century, when forest extent was minimal. This study aimed to (1) reconstruct the forest-line dynamics for the entire French Pyrenees from the mid-19th century until today and (2) investigate the influence of human and environmental drivers on the spatio-temporal variations in forest-line shift. To ascertain the forest-line elevational shift for the 114 municipalities studied, three digital land-use maps (dated 1851, 1993 and 2010) were employed. The forest-line shift velocity was calculated for the two periods delineated by these maps. We applied linear mixed-effect models to analyse the role of human and environmental drivers on the forest-line shift. The mean upward shift was 0.9 m yr−1 during the 1851–1993 period but was four-fold higher during the 1993–2010 period (3.5 m yr−1). During the first period, the forest line shifted upward seven times faster in the eastern Pyrenees, where the mountain pine, a pioneer species, formed the ecotone and pastoral abandonment occurred earlier, than in the western Pyrenees (1.3 vs. 0.2 m yr−1). Conversely, in the following period, the shift occurred three times as fast in the western Pyrenees, where abandonment became widespread, as in the eastern Pyrenees (5.6 vs. 2.1 m yr−1). In addition, during the second period, the closed forest line climbed twice as fast as the forest line (5.6 m yr−1), indicating a pronounced densification of the subalpine forest. Our original approach integrates a large spatial scale and temporal depth and sheds new light on the interrelationships between global warming, pastoral abandonment and the forest-line upward shift.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Delpouve) 13 Mar 2026
https://hal.science/hal-05403814v1
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[hal-05346694] Sylv'Agora, un jeu de négociation sur les enjeux de transition des socio-écosystèmes forestiers
Sylv’Agora est un jeu de rôle qui vise à simuler des négociations d’acteurs sociaux à propos de décisions à prendre sur la gestion d’une forêt fictive. Le jeu comprend 12 acteurs représentatifs de la gestion forestière, des usages de la forêt et du territoire. Chaque personnage a des objectifs à atteindre : achat de bois, mise en conservation écologique de parcelles, droits de pêche et de chasse, maintien des emplois locaux, accès aux espaces, etc. La prise de décision collective porte sur des orientations de gestion d'un socio-écosystème forestier : extension de la réserve actuelle, planification forestière sous la forme de choix sylvicoles, aménagement touristique (parkings, routes). A la fin des négociations, les arbitres veulent s’assurer d’avoir une majorité de « oui » pour le projet retenu de réserve pour éviter les conflits entre acteurs.
ano.nymous@ccsd.cnrs.fr.invalid (Charlotte Michel) 04 Nov 2025
https://hal.science/hal-05346694v1
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[hal-05853585] Rapid assessment of forest area and volume impacted by the 2025 fires in Aude, France
Although forest disturbances occur unpredictably, existing monitoring infrastructures can enable rapid, low-cost assessments. By combining national forest inventory data, canopy height models, and freely available satellite imagery, disturbance extent and forest attributes can be estimated without costly ad-hoc campaigns. Applied to the 2025 wildfires in Southwestern France (June-August), this approach estimated 14,000 ha burned, affecting 143,000 m 3 (±48,000 m 3 ) of productive timber. This report demonstrated the ability to deliver results within three weeks of the last fire, with even faster reporting possible for future events.
ano.nymous@ccsd.cnrs.fr.invalid (Alexander Massey) 05 Nov 2026
https://hal.science/hal-05853585v1
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[hal-05386617] Fire and Herbivory as Architects of Mediterranean Biodiversity
Reconstructing the long‐term interactions between fire and herbivory is essential to understand how Mediterranean vegetation has historically responded to disturbance regimes which is a critical step for informing current biodiversity and fire management strategies. We reconstructed 8000 years of vegetation composition, habitat combustibility, and herbivore density in southern France using pollen data and coprophilous fungal spores. We show that periods of high‐herbivore density systematically co‐occur with open, highly flammable habitats, and significantly correlate with elevated palynological richness. Conversely, cooler and wetter climatic phases promoted the development of closed‐canopy, low‐combustibility forests, which consistently exhibited lower biodiversity levels. In recent centuries, a documented decline in mammal herbivory pressure has coincided with the expansion of fire‐prone vegetation types such as garrigue and green oak coppice, exacerbating landscape combustibility under climate change. Our 8000‐years reconstruction highlights herbivory as a persistent and quantifiable driver of habitat openness, heterogeneity, and fire regime modulation. Synthesis : Our study demonstrates that herbivores and fire have jointly shaped Mediterranean biodiversity over millennia. These findings highlight the need to reintroduce or maintain herbivory as a management tool in fire‐prone Mediterranean ecosystems.
ano.nymous@ccsd.cnrs.fr.invalid (Marion Lestienne) 01 Dec 2025
https://amu.hal.science/hal-05386617v1
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[hal-05620280] Controverse sur l’approvisionnement d’une centrale énergétique de biomasse forestière comme révélateur de la diversité des tensions sur l’usage de la forêt
L’utilisation des forêts dans les politiques de transition énergétique et de décarbonation de l’industrie suscite de nombreuses controverses, impliquant conflits, débats et désaccords dans différents contextes scientifiques, techniques, sociaux et politiques. Nous nous intéressons ici aux controverses publiques, et à leurs dynamiques argumentatives (Chateauraynaud, 2010) dans le cas de la centrale de Provence, cas emblématique, sujet récent d’un complément d’enquête publique. Depuis 2015, la centrale thermique de Gardanne fait l’objet de controverses liées à sa conversion de centrale à charbon à centrale à biomasse, brulant du bois pour produire de l’électricité. Lauréate de l’appel à projets CRE4 (Appels d’offres nationaux d’énergies renouvelables) en 2012, la centrale n’a jamais pu fonctionner de manière continue en raison de contentieux juridiques. Un complément d'étude d’impact a été soumis à enquête publique de mai à juin 2025 concernant les effets indirects de l’approvisionnement en bois de la centrale de Provence, son bilan carbone, et l’évaluation d’incidence Natura 2000. Ce débat public rejoint ainsi un ensemble large de controverses liés à l’usage industriel du bois, touchant une vingtaine de projets en France. Située sur les communes de Gardanne et Meyrargues, la centrale repose par ailleurs dans un territoire marqué par des fronts de tensions entre développement de l’industrie et protection de l’environnement. L’enquête publique, étudiée ici, du fait du périmètre d’approvisionnement, concerne dix-sept départements sur trois régions. Les 1646 contributions de l’enquête publique permettent de cartographier les arguments en croisant les différents avis, les types d’arguments déployés, et les lieux d’expression. L’analyse temporelle permet également de suivre la mobilisation de réseaux d’acteurs. De ces analyses, notre travail dégage, par des méthodes statistiques, une typologie des représentations des usages de la forêt, révélant les lignes de fracture sociales et territoriales autour de la gestion forestière, entre transition énergétique, maintien de l’industrie et conservation écologique.
ano.nymous@ccsd.cnrs.fr.invalid (Charlotte Michel) 12 May 2026
https://hal.science/hal-05620280v1
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[hal-02152674] « De la mise en défens des taillis à la futaie irrégulière à couvert continu : 7 siècles d’évolution de l’aménagement forestier français »
Dès le haut moyen âge, les rois de France, inquiets quant à l’avenir des ressources forestières du royaume, tentèrent de mettre un peu d’ordre dans leur usage. Selon les historiens s’intéressant au domaine forestier , la passion des rois de France pour la chasse serait à l’origine des premiers aménagements forestiers visant à convertir de grands massifs forestiers en futaie , soit un type de peuplement composé d’arbres de taille élevée, plus adapté aux chasses à coure que les ensembles buissonnants et touffus, appelés couramment taillis. Notre communication se propose de réaliser un rapide « balayage » de près de 8 siècles d’évolution de la science forestière française, des toutes premières ordonnances royales du XIIIe siècle jusqu’à la loi forestière dite « Pisani » (1963) qui a remis le domaine forestier privé, en très part négligé par l’État français depuis alors près d’un siècle et demi, sur le devant de l’intervention publique. Avec ce texte, le propriétaire forestier privé se voyait désormais allouer des droits mais aussi des devoirs, ne pouvant plus « user et abuser » de son bien forestier comme bon lui semblait.
ano.nymous@ccsd.cnrs.fr.invalid (Jean-Yves Puyo) 11 Jun 2019
https://univ-pau.hal.science/hal-02152674v1
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[hal-05392448] Projet ciblé NUM-DATA - Développer le partage, l’accessibilité et les «services » d’exploitation des données et des codes
Avec l'ambition d'appuyer la recherche du Programme FORESTT sur la résilience des forêts tempérées et tropicales, le projet NUM-DATA répond à un besoin transverse dans le domaine des données et du numérique, en soutien aux dix projets lauréats de l'appel à projets FORESTT 2025.
ano.nymous@ccsd.cnrs.fr.invalid (Sophie Fortuno) 02 Dec 2025
https://hal.science/hal-05392448v1
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[hal-05310696] Vocabulaires thématiques dans le PEPR FORESTT. Cas d’étude du multirisque
CONTEXTE<p>Les projets du PEPR FORESTT rassemblent des communautés traitant de la résilience des forêts et pour lesquelles la pleine maîtrise du vocabulaire est un enjeu majeur.</p><p>La mobilisation et la consolidation de référentiels thématiques constituent une des actions structurantes de FORESTT.
ano.nymous@ccsd.cnrs.fr.invalid (Nolwenn Peyratout) 13 Oct 2025
https://hal.science/hal-05310696v1
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[hal-05269703] Long-term forest-line dynamics in the French Pyrenees: an accelerating upward shift related to forest context, global warming and pastoral abandonment
<div><p>Worldwide, the upper forest line has climbed over the past decades, shaping mountain landscapes in response to global changes. In European mountains, this recent trend is a continuation of the forest transition initiated in the mid-19 th century, when forest extent was minimal. This study aimed to (1) reconstruct the forest-line dynamics for the entire French Pyrenees from the mid-19 th century until today and (2) investigate the influence of human and environmental drivers on the spatio-temporal variations in forest-line shift. To ascertain the forest-line elevational shift for the 114 municipalities studied, three digital land-use maps (dated 1851, 1993 and 2010) were employed. The forest-line shift velocity was calculated for the two periods delineated by these maps. We applied linear mixed-effect models to analyse the role of human and environmental drivers on the forest-line shift. The mean upward shift was 0.9 m.yr -1 during the 1851-1993 period but was four-fold higher during the 1993-2010 period (3.5 m.yr -1 ). During the first period, the forest line shifted upward seven times faster in the eastern Pyrenees, where the mountain pine, a pioneer species, formed the ecotone and pastoral abandonment occurred earlier, than in the western Pyrenees (1.3 vs. 0.2 m.yr -1 ). Conversely, in the following period, the shift occurred three times as fast in the western Pyrenees, where abandonment became widespread, as in the eastern Pyrenees (5.6 vs. 2.1 m.yr -1 ). In addition, during the second period, the closed forest line climbed twice as fast as the forest line (5.6 m.yr -1 ), indicating a pronounced densification of the subalpine forest. Our original approach integrates a large spatial scale and temporal depth and sheds new light on the interrelationships between global warming, pastoral abandonment and the forest-line upward shift.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Delpouve) 19 Sep 2025
https://hal.science/hal-05269703v1
