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7 Pág., The canker disease caused by Diplodia corticola is one of the most important emerging pathologies of cork oak (Quercus suber) in western Europe. The fungus is dispersed by borer insects, although it is also thought that the spores can be dispersed by wind and rain. The aim of this study was to evaluate the presence of airborne inoculum of D. corticola in managed cork oak stands during cork harvesting season. Semi-passive spore traps were set in eight sampling plots in Catalonia (north-eastern Spain) in summer of 2020. Traps were replaced every week and the number of D. corticolas spores per sampling event was estimated based on a specific nested-qPCR protocol. Spatial-temporal distribution of airborne inoculum accumulation along sampling areas was analyzed using generalized additive models (GAMs). The availability of airborne inoculum resulted rather low with noticeable accumulation peaks in some of the sampled areas. The fitted GAM revealed a positive effect of high air humidity during the sampling period on the availability of spores. This study represents the first attempt to model the spore release of this emerging pathogen, and it provides insights for developing D. corticola canker control strategies based on the precise timing of cork harvesting operations., This work was partially funded by the Generalitat de Catalunya, Departament d'Acció Climàtica, Alimentació i Agenda Rural (Spain). Anand B. Uppara is granted by an Industrial Pre-Doctoral Fellowship at Forest Bioengineering solutions and the Forest Sciences Center of Catalonia (CTFC) (reference: E-25-2020-0115755). Authors thank J. Heras (Generalitat de Catalunya), O. Plana (Diputació de Barcelona), A. Torrell (Forestal Catalana), and J.M. Riba for their helpful advice and support in plot selection and sampling development. Fungal strain CAA007-1 used in molecular procedures was provided by Dr. A. Alves (Universidade de Aveiro, Portugal). Authors especially thank Ajuntament de Tordera, Agents Rurals, the staff of Forestal Catalana, and forest owners for giving support in fieldwork and trap monitoring.

Anyone involved in timber production needs some knowledge of autecology. With the renewed interest in hardwoods in the last 20 years, they are increasingly being introduced by planting or encouraged in natural stands. The results in terms of growth have not always met foresters’ expectations, due to technical problems and especially because the species are not always suited to the different sites. While the principle of establishing hardwoods is not in question, it is important to be aware of the conditions they need for their growth. This is why the first component of the Pirinoble programme is about improving knowledge on the ecology and adaptation of valuable hardwood species. To support this, a wide-ranging bibliographic analysis was made of scientific publications in French, English, Spanish and Italian on the main hardwood species that can be established as plantations: - Wild Cherry (Prunus avium l.), - Common Ash (Fraxinus SSP.), - Wild service tree (Sorbus torminalis l.), service tree (Sorbus domestica L.) and other sorbus species. - Walnut (Juglans SSP.), - Common pear tree (Pyrus pyraster (l.) Du ROI) and the European Wild Apple tree (Malus sylvestris Mill.). - Lime (Tilia ssp.), - Maple (Acer SSP.). Favourable site conditions for hardwood trees are now better understood thanks to numerous observations carried out in stands and a number of scientific studies. Some species have been studied in more depth, including the wild cherry, wild service tree, common ash, maple and walnut. This guide is based on the results of these studies, supplemented by the expertise of the authors. It includes a series of autecology factsheets that describe the site conditions in which hardwoods will thrive and the minimum conditions required for rapid timber production. The factsheets were published on a regular basis in Forêt-entreprise in 2012 and 2013 (see footnote at the end of each of factsheet), and are now published together in this guide along with the bibliographical references consulted.

The agriculture intensification required to provide enough food commodities for humans has negative impacts on the environment. To reduce these drawbacks Agri-Environmental Schemes (AES) have been implemented in Europe since the last decade of the twentieth century. One of the measures included in these schemes was the introduction of alfalfas in crop rotation systems. In order to evaluate their suitability as an AES, we synthesize knowledge on the agronomical benefits of alfalfa cultivations, as well as on the relationships of alfalfa crops with biodiversity at three taxonomic levels: vascular plants, arthropods, and vertebrates. Based on the articles reviewed, alfalfas can help restoring native grassland communities due to the nutrient enrichment they provide. Moreover, this legume crop usually ensures food resources not only for invertebrates, but also for vertebrates. Alfalfas tend to harbour a stable arthropod community that benefits surrounding crops by improving ecological processes (pollination, pest predation) and reducing the need to use agrochemicals. At the same time, arthropod abundance attracts vertebrates, especially birds, which supports the role of alfalfa as a conservation tool to favour endangered farmland birds. Additionally, alfalfa crops may function as a reservoir habitat for voles, which are a preferred food resource for farmland-foraging raptors, many of them endangered. On the other hand, birds nesting in alfalfa crops may suffer higher nest destruction rates due to frequent cuts, and voles using alfalfa crops may also create agricultural damage in surrounding crops in certain cases. The review also highlights that negative ecological relationships of alfalfa crops with biodiversity can be minimized, and positive effects may also be maximized under the appropriate management of this crop. Examples of such management actions include cut delays or higher cuts to avoid nest destruction, the use of grazing cattle to reduce the impacts of rodent pests, reduced frequency of cutting or maintaining unharvested strips in the field to maximize positive effects on predatory arthropods and vole availability to raptors. We conclude that alfalfa crops can be considered globally beneficial for farmland biodiversity and a useful management tool for conservation in agricultural landscapes, for example as an AES, but that management should be adapted to particular taxonomical or functional groups., This paper contributes to project S2018/EMT-4338 REMEDINAL TE-CM from Comunidad de Madrid and Chair UAM-CTFC-TotalEnergies Steppe-Forward.

Farmland ecosystems are seasonally dynamic habitats shaped by meteorological fluctuations and anthropogenic land-use changes. Farmland birds may be seasonally constrained with limited foraging and breeding resources (so-called “resource bottlenecks”), especially when there is a loss of natural and semi-natural habitats. During spring, the growth of cereal crops makes a large proportion of arable land unsuitable for specialist steppe birds with narrow vegetation structure requirements. We investigated the existence of a seasonal bottleneck of suitable habitats for steppe birds using the endangered Pin-tailed sandgrouse (Pterocles alchata) as a model species. We used for first time lightweight GPS tags to study habitat selection and movement patterns throughout the cereal crop cycle during three years in north-eastern Spain. We also evaluated if conservation measures promoting suitable vegetation structures for steppe birds (Targeted Fallow Management, TFM) influenced habitat selection. Sandgrouse avoided cereal crops when cereal vegetation was high, resulting in a 30% reduction of suitable habitat area at the start of the breeding season. This proved the existence of a spring habitat bottleneck when sandgrouse only selected open natural habitats and fallows. Sandgrouse similarly selected TFM and conventionally managed fallows during and after the bottleneck, possibly because of their similar vegetation structure and the scarcity of alternative suitable habitats. Halting the ongoing loss of fallow land is paramount for the conservation of steppe birds like sandgrouse because they constitute a key refuge to buffer the impacts of seasonal habitat bottlenecks., Infrastructures from the Generalitat de Catalunya funded this project. RT was supported by a Juan de la Cierva-Formación [FJCI-2016–28540] and the project "CLU-2019–01 - iuFOR Institute Unit of Excellence" of the University of Valladolid and co-financed by the European Regional Development Fund (ERDF "Europe drives our growth") [CP21/75]. AS-P was partially funded by the Forest Science and Technology Center of Catalonia.

According to climate projections, global warming is associated with increasing temperatures and dry spells in some parts of the world, especially the Mediterranean area. However, it is quite challenging for the scientific community to assess the intensity of these changes, because (i) the trend relies on the greenhouse gases (GHG) emission scenario and (ii) fire occurrence depends on multiple factors (including climate, but not only). A proper assessment of the trend in terms of fire activity still lacks, especially for the French territory. Our study refines traditional approaches of fire risk projection under climate change by translating a danger index into potential fire activity (fire occurrence above 1 ha and burnt area).

In this master s thesis, it is presented the problem of mitigating the damage caused in a landscape by a wildfire. Specifically, in the problem, wildfire managers aim to minimize the impact of a worst-case wildfire on the landscape, by implementing fuel treatment. A min-max interdiction model is formulated. Regarding the solving method, the original problem is reformulated decomposing it into two subproblems which are solved alternatively, one of them exactly and the other one with a heuristic procedure, in an iterative algorithm. The problem, the formulation, and the solving method are described, and the results for a real test case are analysed.

The present document has been performed by the student with the collaboration of CTFC (Forest Technology Center of Catalonia) as the memory of the final degree thesis. The purpose of this thesis is to evaluate the current situation of the legislation and guidelines of the quality of solid biofuels. In order to fulfil this, two main parts are considered: a fieldwork and implementation of improvements. The first part consists of bibliographic research, creation and conduction of surveys to the collectives involved in the supply chain of the energy. The second part consists of the design of controls to implement an audit. Results show the need to create a legislation based on the exisiting guidelines. The current ones only englobes high quality biomass, furthermore addition of new features of classification for lower quality biomass are propose as an improvement. Finally, in order to guarantee the compliance of the legislation a technical audit plan is presented in this thesis. El present document s'ha realitzat per l'alumne amb la col·laboració del CTFC ( centre tecnològic forestal de Catalunya) com a memoràndum del treball final de Grau. El propòsit d'aquest treball és avaluar la situació actual de la legislació i la normativa referent a la qualitat del biocombustible sòlid. A l'hora de realitzar l'objectiu, es consideren dos parts principals: Treball de camp i la implementació de millores. La primera part consisteix en la investigació bibliogràfica, la creació i realització de enquestes als col·lectius involucrats en la cadena de subministrament de l'energia. La segona part consisteix en el disseny de controls per implementar una auditoria. Els resultats mostren la necessitat de crear una legislació basada en les normatives existents, que actualment, només engloben la biomassa de qualitat suprema. Per això, es proposa com a milloria incloure nous paràmetres de classificació per la biomassa de menor qualitat. Finalment, per garantir el compliment de la legislació es presenta un pla d'auditoria tècnic. El presente documento ha sido realizado por parte del estudiante con la colaboración del CTFC (Centro tecnológico forestal de Cataluña) como memoria del Trabajo final de grado. El propósito de este trabajo es evaluar la situación actual de la legislación y la normativa referente a la calidad del biocombustible sólido. Con tal de cumplir este objetivo, se consideran dos partes principales: trabajo de campo y la implementación de mejorías. La primera parte consiste en la investigación bibliográfica, la creación y la realización de encuestas a los colectivos involucrados en la cadena de suministro de la energía. La segunda parte consiste en el diseño de controles para implementar una auditoría. Los resultados reflejan la necesidad de crear una legislación basada en las normativas existentes, que actualmente, sólo engloban la biomasa de alta calidad. Por lo tanto, se propone como mejoría añadir nuevos parámetros de clasificación para la biomasa de menor calidad. Finalmente, para garantizar el cumplimiento de la legislación se presenta un plan de auditoría técnico.

Intraspecific diversity informs the demographic and evolutionary histories of populations, and should be a main conservation target. Although approaches exist for identifying relevant biological conservation units, attempts to identify priority conservation areas for intraspecific diversity are scarce, especially within a multi-specific framework. We used neutral molecular data on six European freshwater fish species (Squalius cephalus, Phoxinus phoxinus, Barbatula barbatula, Gobio occitaniae, Leuciscus burdigalensis and Parachondrostoma toxostoma) sampled at the riverscape scale (i.e. the Garonne-Dordogne River basin, France) to determine hot- and cold-spots of genetic diversity, and to identify priority conservation areas using a systematic conservation planning approach. We demonstrate that systematic conservation planning is efficient for identifying priority areas representing a predefined part of the total genetic diversity of a whole landscape. With the exception of private allelic richness, classical genetic diversity indices (allelic richness, genetic uniqueness) were poor predictors for identifying priority areas. Moreover, we identified weak surrogacies among conservation solutions found for each species, implying that conservation solutions are highly species-specific. Nonetheless, we showed that priority areas identified using intraspecific genetic data from multiple species provide more effective conservation solutions than areas identified for single species or on the basis of traditional taxonomic criteria.

Studying intra-annual growth dynamics through a modelling approach has proved useful for characterizing differences in wood phenology between species and deviations from the expected tree growth due to climate change.The aim of this paper was to determine the climatic factors and the inter-and intra-specific competition traits that drive intra-annual secondary growth dynamics in three Mediterranean tree species that naturally co-exist in the Spanish Northern Plateau (Pinus pinea L., Juniperus thurifera L., and Quercus ilex subsp. ballota (Desf.) Samp.). For this purpose, we obtained girth increment data from band dendrometers installed on 58 trees from May 2012 to April 2015. Half of them were located in a high-density plot and half were in a low-density plot. These data were analysed through a nonlinear multifactorial model considering daily and cumulative climatic effects together with inter-and intra-specific competition indices.Our results provide evidence of a spatiotemporal niche separation between species. Compared with other species, Q. ilex subsp. ballota showed a wider thermal amplitude, a higher mean optimum temperature for growth, and a milder effect of drought on its secondary growth.Under current climate change projections, simulations based on our model predict a secondary growth reduction for P. pinea and a growth enhancement for Q. ilex subsp. ballota in these Mediterranean mixtures.

[EN]: Factors affecting individual diet specialization in generalist populations and the relationship between diet and foraging success remain poorly studied, particularly in terrestrial wide-ranging predators. We studied whether individual variations in diet in Montagu's harrier males (determined through a combination of direct foraging observations and pellet analysis) were associated with patterns of foraging habitat selection and foraging success of 12 radiotracked males during the breeding period. We found important differences in diet composition and breadth between individuals. Diet diversity was negatively related to hunting success: the most efficient individuals in terms of hunting success had the most specialized diet. This study also suggests an important role of individual foraging habitat selection in explaining individual diet, as the proportion of different prey types in the diet was associated with habitat composition within the home range, with higher proportion of those habitats that held higher abundances of their more frequent prey. This study thus provides evidence of individual diet specialization having a knock-on effect on foraging efficiency in a wide-ranging raptor and highlights the role of individual behaviour as a driving force of intra-population niche variation., The authors would like to thank the Centre Tecnològic Forestal de Catalunya for financial and logistic support. BA was supported by a Mobility Grant funded by the Spanish Ministry of Education and Culture (Salvador de Madariaga call, grant number PRX12/00181) while working on this paper in CEBC.

There is increasing evidence that species diversity enhances the temporal stability (TS) of community productivity in different ecosystems, although its effect at the population and tree levels seems to be negative or neutral. Asynchrony in species responses to environmental conditions was found to be one of the main drivers of this stabilizing process. However, the effect of species mixing on the stability of productivity, and the relative importance of the associated mechanisms, remain poorly understood in forest communities. We investigated the way mixing species influenced the TS of productivity in Pinus sylvestris L.;Fagus sylvatica L. forests, and attempted to determine the main drivers among overyielding, asynchrony between species annual growth responses to environmental conditions, and temporal shifts in species interactions. We used a network of 93 experimental plots distributed across Europe to compare the TS of basal area growth over a 15-year period (1999–2013) in mixed and monospecific forest stands at different organizational levels, namely the community, population and individual tree levels. Mixed stands showed a higher TS of basal area growth than monospecific stands at the community level, but not at the population or individual tree levels. The TS at the community level was related to asynchrony between species growth in mixtures, but not to overyielding nor to asynchrony between species growth in monospecific stands. Temporal shifts in species interactions were also related to asynchrony and to the mixing effect on the TS. Synthesis. Our findings confirm that species mixing can stabilize productivity at the community level, whereas there is a neutral or negative effect on stability at the population and individual tree levels. The contrasting findings regarding the relationships between the temporal stability and asynchrony in species growth in mixed and monospecific stands suggest that the main driver in the stabilizing process may be the temporal niche complementarity between species rather than differences in species’ intrinsic responses to environmental conditions. © 2016 The Authors. Journal of Ecology © 2016 British Ecological Society

Scenario-based modelling for management of Mediterranean forests: a review.. International conference on scenarios and models

Aim of study: The program "Typology of truffle stations in the Pyrenean Regions" aimed to define the ecological conditions and culture practices that favor Tuber melanosporum growth and fruiting in this area.Area of study: Navarra, Catalonia, Midi-Pyrénées and Languedoc-Roussillon.Material and methods: The program was based on the survey of 212 wild and cultivated truffle beds of evergreen oaks (Quercus ilex). The data collected in the field consisted of photographs, samples of soil, roots and mycorrhizae, and information on cultural practices followed by truffle growers.Main results: (i) truffle soils are alkaline, from neutral, dolomitic, to moderately or very calcareous soils; (ii) truffle soils are light, well-structured and stable to water immersion; (iii) mycelium that colonizes roots survives in suboptimal conditions, but it does not necessarily bear ascocarps. Finally our results suggest that T. melanosporum is a relatively ubiquitous fungus able to grow, or at least to persist, in a wide range of physical and chemical soil conditions. We propose a probabilistic model of the environment favorable for fruiting, built around a two-dimensional graph with an axis for the chemical conditions, like soil alkalinity, and another axis for the physical conditions, like soil structure. Research highlights: Soil alkalinity and structure allow to built a convenient representation of the ecological capacity of a place to be good T. melanosporum habitat, and thus of the probability for truffle growers to harvest truffles according to the environmental properties of their truffle orchards.Keywords: dolomite; limestone; mycorrhizae; Quercus ilex; field survey; Tuber melanosporum.

Guide réalisé dans le cadre du projet européen interreg 4a « Pirinoble » ; National audience; Dans le cadre du projet européen Pirinoble (www.pirinoble.eu), une synthèse a été réalisée sur l’autécologie des principaux feuillus précieux. Les résultats sont présentés sous forme de fiches par essence qui seront régulièrement publiées dans Forêt-entreprise. Ce « Guide de lecture » précise les définitions et termes utilisés. La première fiche concernant le merisier est publiée en pages suivantes de 9 à 12.

Fiche réalisée dans le cadre du projet européen interreg 4a « Pirinoble » (www.pirinoble.eu) associant quatre partenaires français et espagnols : CNPF - Institut pour le Développement Forestier (IDF), Centre Régional de la Propriété Forestière de Midi-Pyrénées (CRPF), Centre Tecnològic Forestal de Catalunya CTFC), Centre de la Propietat Forestal (CPF).

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Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36-55% of alpine species, 31-51% of subalpine species and 19-46% of montane species lose more than 80% of their suitable habitat by 2070-2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVIN [Coll_IRSTEA]Forest and landscape working papers n° 35; International audience; Light quantity and light quality are two of the main environmental factors controlling the success of seed germination, seedling establishment and growth of trees in the understorey of our temperate forests. Increasing light availability by the practice of thinning also promotes the development of the ground vegetation, graminoids, forbs and shrubs, which may affect tree regeneration. These plants can intercept a significant fraction of the available light in the understorey and thus the resulting amount of light available for tree seedlings can vary greatly depending on species and composition of ground vegetation. Assessing light capture within such complex distribution of vegetation still faces many technical challenges. Measuring light directly in the understorey of forest stands, taking into account the ground vegetation, can be very tedious and expensive. Therefore mathematical methods, dealing with plant architecture, are being developed to resolve light capture by tree seedlings in contrasting understorey situations. Many models have dealt with light transmission through forest overstorey whereas the understorey vegetation is often not taken into consideration. We will synthesize results on light measurement under different understorey species (Rubus fruticosus, Rubus idaeus, Epilobium angustifolium, Cytisus scoparius, Calluna vulgaris, Molinia caerulea, Pteridium aquilinum), provide some modeling options for light capture computations, and discuss potential consequences for tree regeneration.

1. Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2. We review the development of plant facilitation research, focusing on the history of the field, the relationship between plant–plant interactions and environmental severity gradients, and attempts to integrate facilitation into mainstream ecological theory. We then consider future directions for facilitation research. 3. With respect to our fundamental understanding of plant facilitation, clarification of the relationship between interactions and environmental gradients is central for further progress, and necessitates the design and implementation of experiments that move beyond the clear limitations of previous studies. 4. There is substantial scope for exploring indirect facilitative effects in plant communities, including their impacts on diversity and evolution, and future studies should connect the degree of non‐transitivity in plant competitive networks to community diversity and facilitative promotion of species coexistence, and explore how the role of indirect facilitation varies with environmental severity. 5. Certain ecological modelling approaches (e.g. individual‐based modelling), although thus far largely neglected, provide highly useful tools for exploring these fundamental processes. 6. Evolutionary responses might result from facilitative interactions, and consideration of facilitation might lead to re‐assessment of the evolution of plant growth forms. 7. Improved understanding of facilitation processes has direct relevance for the development of tools for ecosystem restoration, and for improving our understanding of the response of plant species and communities to environmental change drivers. 8. Attempts to apply our developing ecological knowledge would benefit from explicit recognition of the potential role of facilitative plant–plant interactions in the design and interpretation of studies from the fields of restoration and global change ecology. 9. Synthesis: Plant facilitation research provides new insights into classic ecological theory and pressing environmental issues. Awareness and understanding of facilitation should be part of the basic ecological knowledge of all plant ecologists. This review was an outcome of the conference ‘Facilitation,Biodiversity, Invasibility in a Changing World’, held from 4 to7 September 2006 at the University of Bordeaux’s Marine Bio-logical Station, Arcachon, France. We gratefully acknowledgethe financial support provided for this meeting by theEuropean Science Foundation, and thank Pierre Chardy andXavier de Montaudouin for hosting the meeting. We thank allconference participants for stimulating discussions. R.W.B.would like to acknowledge support for writing this paperfrom the Scottish Executive Environment and Rural AffairsDepartment, and the use of Ray Callaway’s reference database for production of the supplementary material. F.T.M.acknowledges support from a Ramón y Cajal contract awardedby the Spanish Ministerio de Educación y Ciencia and fromthe British Ecological Society (ECPG 231/607).

[Notes_IRSTEA]attention : en 2012 uniquement en first published online, donc pas encore paginé, probablement parution en 2013 ; pagination attribuée pour 2013 (information en date de janv 2013) [Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVIN; Bramble (Rubus fruticosus L.) is a common weed in temperate forest and also in other world ecosystems where it is recorded as an invasive plant. Although it has been described to efficiently compete for water and nutrients, little is known on its competitive ability for light. We described bramble canopy architecture, cover relative to light availability and light interception ability in 60 areas of bramble thicket at 17 sites in France and 1 in England with contrasting soils and climates. The leaf area and leaf number can be predicted by the cane (shoot) length. The leaf inclination distribution was planophile (i.e. leaf laminas distributed in the horizontal plane). There was a good relationship between light interception and leaf area index (LAI) of the different bramble thickets, with no significant site influence, meaning that a single model can be used to predict light interception by bramble in different conditions. Bramble LAI and cover rapidly increased with light availability in the understorey to reach almost 20% cover at only 5–7% light availability above the thicket. Consequently, bramble is able to tolerate deep shade, which is not in accordance with its reputed moderate to high light requirement reported in the literature and suggests that it is difficult to control this species by manipulating tree canopy. This would have adverse consequences on tree regeneration.

Fire has been a source of global biodiversity for millions of years. However, interactions with anthropogenic drivers such as climate change, land use, and invasive species are changing the nature of fire activity and its impacts. We review how such changes are threatening species with extinction and transforming terrestrial ecosystems. Conservation of Earth’s biological diversity will be achieved only by recognizing and responding to the critical role of fire. In the Anthropocene, this requires that conservation planning explicitly includes the combined effects of human activities and fire regimes. Improved forecasts for biodiversity must also integrate the connections among people, fire, and ecosystems. Such integration provides an opportunity for new actions that could revolutionize how society sustains biodiversity in a time of changing fire activity., The workshop leading to this paper was funded by the Centre Tecnològic Forestal de Catalunya and the ARC Centre of Excellence for Environmental Decisions. LTK was funded by a Victorian Postdoctoral Research Fellowship (Victorian Government), a Centenary Fellowship 15 (University of Melbourne) and an Australian Research Council Linkage Project (LP150100765). AR funded by the Xunta de Galicia (Postdoctoral Fellowship ED481B2016/084-0) and the Foundation for Science and Technology under the FirESmart project (PCIF/MOG/0083/2017). ALS was supported by a Marie Skłodowska-Curie Individual Fellowship (746191) under the European Union Horizon 2020 Programme for Research and Innovation. LB was partially 20 funded by the Spanish Government through the INMODES (CGL2014-59742-C2-2-R) and the ERANET-SUMFORESTS project FutureBioEcon (PCIN-2017-052)

[Departement_IRSTEA]GT [TR1_IRSTEA]SET / BIOFOR; International audience; Two-year-old Fagus sylvatica L. saplings were planted under the cover of a Pinus sylvestris L. stand in the Massif Central (France). The stand was thinned to different degrees to obtain a gradient of transmitted PAR (0-0.35). Eighteen Fagus saplings were sampled in this gradient and their growth (basal stem diameter increment) were recorded during six years. In the same time morphological parameters (leaf area, number and arrangement in space) were monitored using 3D-digitizing. Photosynthesis parameters (leaf nitrogen content, Vcmax, Jmax, Rd) were estimated with a portable gas-exchange analyser. Sapling photosynthesis was mainly linked to light availability while their morphology was more driven by sapling size. Annual sapling stem diameter increment was related to the amount of light-intercepting foliage (silhouette to total leaf area ratio (STAR) * total sapling leaf area (LA)) and light availability above the saplings (PARt). However, the light use efficiency, i.e. the slope of the relationship between STAR * LA * PARt and stem diameter increment, decreased over time. This decrease is due to a size effect, i.e. a relative decrease of the proportion of photosynthetic tissues in comparison with the total biomass of the sapling.

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.