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Survie des semis de ligneux pionniers dans les lits fluviaux : approche in et ex situ des facteurs de contrôle abiotiques et biologiques des espèces Populus nigra et Salix alba / Coraline Lise Wintenberger in Géomorphologie, vol 23 ([01/10/2017])
[article]
Titre : Survie des semis de ligneux pionniers dans les lits fluviaux : approche in et ex situ des facteurs de contrôle abiotiques et biologiques des espèces Populus nigra et Salix alba Type de document : Article/Communication Auteurs : Coraline Lise Wintenberger, Auteur ; Stéphane Rodrigues, Auteur ; Philippe Jugé, Auteur ; Marc Villar, Auteur Année de publication : 2017 Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] crue
[Termes IGN] érosion hydrique
[Termes IGN] Loire (bassin)
[Termes IGN] Populus nigra
[Termes IGN] Salix albaRésumé : (auteur) La survie des semis de ligneux pionniers aux contraintes exercées lors des épisodes de crue subséquents à leur recrutement dépend des contraintes hydro-sédimentaires exercées mais également de leur capacité à résister à ces contraintes. L’objectif de cette étude est de comprendre à fine résolution spatio-temporelle les conditions de survie des semis des espèces Populus nigra et Salix alba aux crues survenant après leur recrutement. Une double approche in et ex situ a été conduite permettant (i) de caractériser les contraintes exercées sur les semis au cours des épisodes de crue et (ii) d’analyser leur capacité de résistance aux contraintes. L’approche in situ s’est focalisée sur une barre sédimentaire de centre de chenal localisée en Loire moyenne. Des mesures de topographie, bathymétrie, courantométrie et granulométrie ont permis de caractériser l’intensité, l’évolution temporelle et la répartition spatiale des forces de traînée impliquées dans l’arrachage des semis, des processus d’érosion-dépôt respectivement responsables de l’excavation et de l’enfouissement des semis. Les résultats montrent que la dynamique hydro-sédimentaire spécifique de la barre sédimentaire colonisée a une influence sur la répartition de la survie des semis. L’approche ex situ a permis de caractériser la diversité de croissance du système racinaire et de la partie aérienne des semis en fonction du substrat ainsi que les forces nécessaires à l’arrachage des semis et leur résistance à l’enfouissement. La confrontation des mesures réalisées ex situ avec les contraintes exercées in situ permettent d’affiner la compréhension de la répartition de la survie des semis sur la barre forcée. Numéro de notice : A2017-523 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.4000/geomorphologie.11789 En ligne : http://geomorphologie.revues.org/11789 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86541
in Géomorphologie > vol 23 [01/10/2017][article]The potential of multifrequency SAR images for estimating forest biomass in Mediterranean areas / Emanuele Santi in Remote sensing of environment, vol 200 (October 2017)
[article]
Titre : The potential of multifrequency SAR images for estimating forest biomass in Mediterranean areas Type de document : Article/Communication Auteurs : Emanuele Santi, Auteur ; Simonetta Paloscia, Auteur ; Simone Pettinato, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 63 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] bande C
[Termes IGN] bande L
[Termes IGN] biomasse forestière
[Termes IGN] capacité de stockage
[Termes IGN] classification par réseau neuronal
[Termes IGN] forêt méditerranéenne
[Termes IGN] image ALOS-PALSAR
[Termes IGN] image Envisat-ASAR
[Termes IGN] image radar moirée
[Termes IGN] modèle de transfert radiatif
[Termes IGN] production primaire brute
[Termes IGN] Toscane (Italie)Résumé : (auteur) The extraction of forest information from SAR images is particularly complex in Mediterranean areas, since they are characterized by high spatial fragmentation and heterogeneity. We have investigated the use of multi-frequency SAR data from different sensors (ALOS/PALSAR and ENVISAT/ASAR) for estimating forest biomass in two test areas in Central Italy (San Rossore and Molise), where detailed in-situ measurements and Airborne Laser Scanning (ALS) data were available. The study focused on the estimation of growing stock volume (GS, in m3/ha) by using an inversion algorithm based on artificial neural networks (ANN). The ANN algorithm was first appropriately trained using the available GS estimates obtained from ALS data. The potential of this algorithm was then improved through the innovative use of a simulated dataset, generated by a forward electromagnetic model based on the Radiative Transfer Theory (RTT). The algorithm is able to merge SAR data at L and C bands for predicting GS in diversified Mediterranean environments. The performed analyses indicated that GS was correctly estimated by integrating information from L and C bands on both test areas, with the following statistics: R > 0.97 and RMSE = 28.5 m3/ha for the independent test, and R = 0.86 and RMSE ≈ 77 m3/ha for the final independent validation, the latter performed on the forest stands of both areas not included in the ALS acquisitions and where conventional measurements were available. The research then illustrates the potential of using the obtained GS estimates from SAR data to drive the simulations of forest net primary production (NPP). This experiment produced spatially explicit estimates of GS current annual increments that are slightly less accurate than those obtained from ground observations (R = 0.75 and RMSE ≈ 1.5 m3/ha/year). Numéro de notice : A2017-415 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2017.07.038 En ligne : https://doi.org/10.1016/j.rse.2017.07.038 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86307
in Remote sensing of environment > vol 200 (October 2017) . - pp 63 - 73[article]Variance of light-related foliar traits across spatial and temporal scales in the Mediterranean evergreen Olea europaea L. / Adrián G. Escribano-Rocafort in Perspectives in Plant Ecology, Evolution and Systematics, vol 28 (October 2017)
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Titre : Variance of light-related foliar traits across spatial and temporal scales in the Mediterranean evergreen Olea europaea L. Type de document : Article/Communication Auteurs : Adrián G. Escribano-Rocafort, Auteur ; Agustina B. Ventre-Lespiaucq, Auteur ; Carlos Granado-Yela, Auteur ; et al., Auteur Année de publication : 2017 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes IGN] climat méditerranéen
[Termes IGN] distribution spatiale
[Termes IGN] feuille (végétation)
[Termes IGN] houppier
[Termes IGN] Olea europaea
[Termes IGN] variance
[Termes IGN] variation saisonnièreRésumé : (auteur) The variability in space and time of a given set of traits can describe the biological activity of plants and influence species interactions and the properties of communities and ecosystems. However, seasonal variance in foliar traits of tree species has been poorly addressed in the Mediterranean climate despite its potential implications in fundamental processes such as light interception strategies.
Due to seasonal variation in the apparent sun path’s trajectory, predictable radiation patterns across crown positions may determine the variance partitioning for light-related leaf traits in evergreens. We hypothesize that in the most exposed part of the crown i.e. south, trait variance should be constrain due to abiotic stress compared to less exposed crown positions.
We partitioned the variance across five nested scales for a set of traits that capture leaf form, structure, position relative to the sun and the potential area exposed in a given time in Olea europaea L. trees. The scales included temporal variation due to sampling in two different seasons and twelve spatially structured crown positions within trees. We conducted multivariate analyses to assess the variability among traits, within trees and among trees
The variance partitioning at the season scale was low and the structure conserved between seasons for most traits. Intraindividual variance was conspicuous for all traits evidencing a spatial gradient of trait distribution within trees from outer to inner layers and among paired crown sectors (North-East, South-West). Leaf angles and potential exposure to direct light had an absence of variance at scales above crown positions.
The spatial distribution of crown sectors and layers had a distinct influence on the expression of leaf attributes among traits. Environmental filters may constrain variability on the outermost layer of the crown and on all crown positions during summer and winter, due to combination of the high irradiance and water stress in Mediterranean climates.Numéro de notice : A2017-390 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE Nature : Article DOI : 10.1016/j.ppees.2017.07.003 En ligne : https://doi.org/10.1016/j.ppees.2017.07.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85889
in Perspectives in Plant Ecology, Evolution and Systematics > vol 28 (October 2017)[article]Wind loads and competition for light sculpt trees into self-similar structures / Christophe Eloy in Nature communications, vol 8 (2017)
[article]
Titre : Wind loads and competition for light sculpt trees into self-similar structures Type de document : Article/Communication Auteurs : Christophe Eloy, Auteur ; Meriem Fournier, Auteur ; André Lacointe, Auteur ; Bruno Moulia, Auteur Année de publication : 2017 Langues : Anglais (eng) Descripteur : [Termes IGN] arbre (flore)
[Termes IGN] croissance des arbres
[Termes IGN] données allométriques
[Termes IGN] modèle numérique
[Termes IGN] rayonnement lumineux
[Termes IGN] structure de la végétation
[Termes IGN] vent
[Vedettes matières IGN] BotaniqueRésumé : (auteur) Trees are self-similar structures: their branch lengths and diameters vary allometrically within the tree architecture, with longer and thicker branches near the ground. These tree allometries are often attributed to optimisation of hydraulic sap transport and safety against elastic buckling. Here, we show that these allometries also emerge from a model that includes competition for light, wind biomechanics and no hydraulics. We have developed MECHATREE, a numerical model of trees growing and evolving on a virtual island. With this model, we identify the fittest growth strategy when trees compete for light and allocate their photosynthates to grow seeds, create new branches or reinforce existing ones in response to wind-induced loads. Strikingly, we find that selected trees species are self-similar and follow allometric scalings similar to those observed on dicots and conifers. This result suggests that resistance to wind and competition for light play an essential role in determining tree allometries. Numéro de notice : A2017-780 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1038/s41467-017-00995-6 En ligne : https://doi.org/10.1038/s41467-017-00995-6 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88980
in Nature communications > vol 8 (2017)[article]Tree size thresholds produce biased estimates of forest biomass dynamics / Eric B. Searle in Forest ecology and management, vol 400 (15 September 2017)
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Titre : Tree size thresholds produce biased estimates of forest biomass dynamics Type de document : Article/Communication Auteurs : Eric B. Searle, Auteur ; Han Y.H. Chen, Auteur Année de publication : 2017 Article en page(s) : pp 468 - 474 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse aérienne
[Termes IGN] changement climatique
[Termes IGN] diamètre des arbres
[Termes IGN] échantillonnage
[Termes IGN] erreur systématique
[Termes IGN] estimation statistique
[Termes IGN] forêt boréale
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Manitoba (Canada)
[Termes IGN] placette d'échantillonnage
[Termes IGN] seuillage
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Studies that examine forest biomass dynamics often rely on long-term, spatially extensive, repeatedly measured permanent sample plots. Due to the intensive cost of sampling all trees within these plots, an arbitrary size threshold is typically imposed, which leads to only larger trees being sampled. However, it remains unclear whether the sampling of only large trees is representative of the entirety of stands of diverse sizes; the sampling of only large trees may produce biased estimates of biomass dynamics (growth, ingrowth, and mortality). Using a network of 141 permanent sample plots from Manitoba, Canada, with all trees of >1.3 m in height repeatedly measured, we constructed three distinct data sets, with 10 cm, 5 cm, and no diameter at breast height threshold, to illustrate that total productivity and mortality are increasingly underestimated with increasingly larger diameter at breast height thresholds. This effect is particularly significant in young stands, where productivity estimates peak at least 20 years earlier than the determined estimates under large thresholds. We highlight the need to account for smaller trees in long-term observational studies to ensure unbiased estimates of stand level aboveground biomass productivity and loss. Numéro de notice : A2017-807 Affiliation des auteurs : non IGN Thématique : FORET/MATHEMATIQUE Nature : Article DOI : 10.1016/j.foreco.2017.06.042 En ligne : https://doi.org/10.1016/j.foreco.2017.06.042 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89245
in Forest ecology and management > vol 400 (15 September 2017) . - pp 468 - 474[article]Understanding the temporal behavior of crops using Sentinel-1 and Sentinel-2-like data for agricultural applications / Amanda Veloso in Remote sensing of environment, vol 199 (15 September 2017)PermalinkBiodiversity effects on ecosystem functioning in a 15-year grassland experiment: patterns, mechanisms, and open questions / Wolfgang W. Weisser in Basic and Applied Ecology, vol 23 (September 2017)PermalinkCrown bulk density and fuel moisture dynamics in Pinus pinaster stands are neither modified by thinning nor captured by the Forest Fire Weather Index / Marc Soler Martin in Annals of Forest Science, vol 74 n° 3 (September 2017)PermalinkEvaluation de variables limnologiques grâce à des images Landsat / Danielle Teixeira Alves Da Silva in Géomatique expert, n° 118 (septembre - octobre 2017)PermalinkForest canopy height estimation using satellite laser altimetry : a case study in the Western Ghats, India / S.M. Ghosh in Applied geomatics, vol 9 n° 3 (September 2017)PermalinkForest change detection in incomplete satellite images with deep neural networks / Salman H. Khan in IEEE Transactions on geoscience and remote sensing, vol 55 n° 9 (September 2017)PermalinkFunctional response trait analysis improves climate sensitivity estimation in beech forests at a trailing edge / Éva Salamon-Albert in Forests, vol 8 n° 9 (September 2017)PermalinkImproving the prediction of African savanna vegetation variables using time series of MODIS products / Miriam Tsalyuk in ISPRS Journal of photogrammetry and remote sensing, vol 131 (September 2017)PermalinkInventaire faune, flore et habitats sur la zone humide de Petelin (Corbelin et Veyrins-Thuellin, Nord-Isère) / Alexandre Gauthier in Lo Parvi, n° 25 (2017)PermalinkA mangrove forest map of China in 2015: Analysis of time series Landsat 7/8 and Sentinel-1A imagery in Google Earth Engine cloud computing platform / Bangqian Chen in ISPRS Journal of photogrammetry and remote sensing, vol 131 (September 2017)Permalink