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Year-to-year crown condition poorly contributes to ring width variations of beech trees in French ICP level I network / Clara Tallieu in Forest ecology and management, Vol 465 (1st June 2020)  

Public [article]  inForest ecology and management > Vol 465 (1st June 2020) . - 15 p. Titre : Year-to-year crown condition poorly contributes to ring width variations of beech trees in French ICP level I network Type de document : Article/Communication Auteurs : Clara Tallieu, Auteur ; Vincent Badeau, Auteur ; Denis Allard, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 15 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] apprentissage automatique [Termes IGN] classification par forêts d'arbres décisionnels [Termes IGN] dendrochronologie [Termes IGN] Fagus (genre) [Termes IGN] Fagus sylvatica [Termes IGN] feuille (végétation) [Termes IGN] houppier [Termes IGN] indice foliaire [Termes IGN] pollution atmosphérique [Termes IGN] sécheresse [Termes IGN] stress hydrique [Termes IGN] surveillance forestière [Termes IGN] variation saisonnière [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Since the 1980-90′s episodes of decline in Central European Forests, forest condition has been surveyed thanks to the trans-national network the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). It has been traditionally accepted that leaf loss is directly related to impairment of physiological condition of the tree. A few studies tried to correlate crown condition and growth trends while others concentrated on linking annual growth with crown observation at one date clustered into fertility classes. However, none focussed on the high frequency synchronism between leaf loss from annual network observations and annual radial growth issued from dendrochronology. Therefore, we jointly studied annual leaf loss observations and tree-ring width measurements on 715 common beech (Fagus sylvatica L.) trees distributed in the French part of the ICP monitoring network. Detrended inter-annual variations of leaf loss and tree-ring width index were used as response variables in the machine-learning algorithm Random Forest to investigate a common response to abiotic (current and lagged) and biotic hazards, to test the extent to which leaf loss helped to predict inter-annual variations in radial growth. Using Random Forest was effective to identify a common sensitivity to soil water deficit at different time lags. Previous-year climatic variables tended to control leaf loss while radial growth was more sensitive to current-year soil water deficit. Late frost damages were observed on crown condition in mountainous regions but no impact was detected on radial growth. Few significant biotic damages were observed on growth or leaf loss. Leaf loss series did not show a clear common signal among trees from a plot as did radial growth and captured fewer pointer years. Radial growth index did not fall below normal until a 20% leaf loss was reached. However, this threshold is driven by a few extreme leaf loss events. As shown by our joint analysis of leaf loss and radial growth pointer years, no relationship occurred in cases of slight or moderate defoliation. Crown condition is a poorer descriptor of tree vitality than radial growth. Numéro de notice : A2020-287 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.foreco.2020.118071 Date de publication en ligne : 01/04/2020 En ligne : https://doi.org/10.1016/j.foreco.2020.118071 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95111 [article]

Quantifying spatial heterogeneity at the landscape scale using variogram models / S. Garrigues in Remote sensing of environment, vol 103 n° 1 (15 July 2006)  

Public [article]  inRemote sensing of environment > vol 103 n° 1 (15 July 2006) . - pp 81 - 96 Titre : Quantifying spatial heterogeneity at the landscape scale using variogram models Type de document : Article/Communication Auteurs : S. Garrigues, Auteur ; Denis Allard, Auteur ; F. Baret, Auteur ; M. Weiss, Auteur Année de publication : 2006 Article en page(s) : pp 81 - 96 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] couvert végétal [Termes IGN] erreur systématique [Termes IGN] hétérogénéité spatiale [Termes IGN] image à basse résolution [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] pixel [Termes IGN] utilisation du sol [Termes IGN] variogramme Résumé : (Auteur) The monitoring of earth surface dynamic processes at a global scale requires high temporal frequency remote sensing observations which are provided up to now by moderate spatial resolution sensors. However, the spatial heterogeneity within the moderate spatial resolution pixel biases non-linear estimation processes of land surface variables from remote sensing data. To limit its influence on the description of land surface processes, corrections based on the quantification of the intra-pixel heterogeneity may be applied to non-linear estimation processes. A complementary strategy is to define the proper pixel size to capture the spatial variability of the data and minimize the intra-pixel variability. This work provides a methodology to characterize and quantify the spatial heterogeneity of landscape vegetation cover from the modeling of the variogram of high spatial resolution NDVI data. NDVI variograms for 18 landscapes extracted from the VALERI database show that the land use is the main factor of spatial variability as quantified by the variogram sill. Crop sites are more heterogeneous than natural vegetation and forest sites at the landscape level. The integral range summarizes all structural parameters of the variogram into a single characteristic area. Its square root quantifies the mean length scale (i.e. spatial scale) of the data, which varies between 216 and 1060 m over the 18 landscapes considered. The integral range is also used as a yardstick to judge if the size of an image is large enough to measure properly the length scales of the data with the variogram. We propose that it must be smaller than 5% of the image surface. The theoretical dispersion variance, computed from the variogram model, quantifies the spatial heterogeneity within a moderate resolution pixel. It increases rapidly with pixel size until this size is larger than the mean length scale of the data. Finally based on the analysis of 18 landscapes, the sufficient pixel size to capture the major part of the spatial variability of the vegetation cover at the landscape scale is estimated to be less than 100 m. Since for all the heterogeneous landscapes the loss of NDVI spatial variability was small at this spatial resolution, the bias generated by the intra-pixel spatial heterogeneity on non-linear estimation processes will be reduced. Copyright Elsevier Numéro de notice : A2006-283 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.03.013 En ligne : https://doi.org/10.1016/j.rse.2006.03.013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28010 [article]

Detecting regions of abrupt change : Wombling procedure and statistical significance / Jean-François Gleyze (2001)

Public contenu dans Geomatics for environmental applications, geoENV III, Avignon, France, November 22-24 2000 / Pascal Monestiez (2001) Titre : Detecting regions of abrupt change : Wombling procedure and statistical significance Type de document : Article/Communication Auteurs : Jean-François Gleyze , Auteur ; J.N. Bacro, Auteur ; Denis Allard, Auteur Editeur : Dordrecht : Kluwer Academic Publishers Année de publication : 2001 Conférence : GeoEnv 2000, 3rd European conference on geostatistics for environmental Applications, GeoEnv 3 22/11/2000 24/11/2000 Avignon France Importance : pp 311 - 322 Langues : Anglais (eng) Numéro de notice : C2000-035 Affiliation des auteurs : COGIT+Ext (1988-2011) Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103357

Geomatics for environmental applications, geoENV III, Avignon, France, November 22-24 2000 / Pascal Monestiez (2001)

Public Titre : Geomatics for environmental applications, geoENV III, Avignon, France, November 22-24 2000 : Proceedings of the third European conference on geostatistics for environmental applications Type de document : Actes de congrès Auteurs : Pascal Monestiez, Éditeur scientifique ; Denis Allard, Éditeur scientifique ; Roland Froidevaux, Éditeur scientifique Editeur : Dordrecht : Kluwer Academic Publishers Année de publication : 2001 Conférence : GeoEnv 2000, 3rd European conference on geostatistics for environmental Applications, GeoEnv 3 22/11/2000 24/11/2000 Avignon France Importance : 540 p Format : 16 x 24 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatiale [Termes IGN] géostatistique [Termes IGN] krigeage [Termes IGN] pédologie [Termes IGN] pollution atmosphérique [Termes IGN] précipitation [Termes IGN] régression [Termes IGN] simulation Index. décimale : CG2000 Actes de congrès en 2000 Résumé : (Editeur) This volume contains selected contributions from geoENV III - the Third European Conference on Geostatistics for Environmental Sciences, held in Avignon, France in November 2000. This third book of the geoENV series illustrates the new methodological developments in geostatistics, as applied to environmental sciences, which have occurred during the last two years. It also presents a wide variety of practical environmental applications which will be of interest to both researchers and practitioners. The book starts with two keynote papers on hydrogeology and on climatology and atmospheric pollution, followed by forty contributions. The content of this book is foremost practical. The editors have endeavored to compile a set of papers in which the readers could perceive how geostatistics is applied within environmental sciences. A few selected methodological and theoretical contributions are also included. The papers are organised in the following sections: + Air Pollution / Climate; + Environment; + Health / Ecology; + Hydrology; + Methods; + Soil Science / Site Remediation. Presenting applications varying from delineation of hazardous areas, monitoring water quality, space-time modeling of sand beaches, areal rainfall estimation, air pollution monitoring, multivariate conditional simulation, soil texture analysis, fish abundance analysis, tree productivity index estimation, radionuclide migration analysis, wombling procedure, tracer tests modeling, direct sequential co-simulation to stochastic modeling of flow and transport. Audience: This publication will be of great interest and practical value to geostatisticians working both in academia and in industry. Note de contenu : 1 - Keynote papers 2 - Air pollution / Climate 3 - Environment 4 - Health / Ecology 5 - Hydrology 6 - Methods 7 - Soil science / Site remediation 8 - Poster presentation Numéro de notice : 21513 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Actes nature-HAL : DirectOuvrColl/Actes Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90359

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• Detecting regions of abrupt change : Wombling procedure and statistical significance / Jean-François Gleyze (2001)

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
21513-01	CG2000	Livre	Centre de documentation	Congrès	Disponible