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Improving aboveground biomass estimates by taking into account density variations between tree components / Antoine Billard in Annals of Forest Science [en ligne], vol 77 n° 4 (December 2020)  

Public [article]  inAnnals of Forest Science [en ligne] > vol 77 n° 4 (December 2020) . - n° 103 Titre : Improving aboveground biomass estimates by taking into account density variations between tree components Type de document : Article/Communication Auteurs : Antoine Billard, Auteur ; Rodolphe Bauer, Auteur ; Frédéric Mothe, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 103 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] allométrie [Termes descripteurs IGN] base de données forestières [Termes descripteurs IGN] biomasse aérienne [Termes descripteurs IGN] bois de chauffage [Termes descripteurs IGN] branche (arbre) [Termes descripteurs IGN] diamètre à hauteur de poitrine [Termes descripteurs IGN] écorce [Termes descripteurs IGN] hauteur des arbres [Termes descripteurs IGN] résineux [Termes descripteurs IGN] tomographie radar [Termes descripteurs IGN] volume en bois [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Key message: Strong density differences were observed between stem wood at 1.30 m and other tree components (stem wood, stem bark, knots, branch stumps and branches). The difference, up to 40% depending on the component, should be taken into account when estimating the biomass available for industrial uses, mainly fuelwood and wood for chemistry. Context: Basic density is a major variable in the calculation of tree biomass. However, it is usually measured on stem wood only and at breast height. Aims: The objectives of this study were to compare basic density of stem wood at 1.30 m with other tree components and assess the impact of differences on biomass. Methods: Three softwood species were studied: Abies alba Mill., Picea abies (L.) H. Karst., Pseudotsuga menziesii (Mirb.) Franco. X-Ray computed tomography was used to measure density. Results: Large differences were observed between components. Basic density of components was little influenced by tree size and stand density. Overall, bark, knot and branch biomasses were highly underestimated by using basic density measured at 1.30 m. Conclusion: Using available wood density databases mainly based on breast height measurements would lead to important biases (up to more than 40%) on biomass estimates for some tree components. Further work is necessary to complete available databases. Numéro de notice : A2020-714 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-020-00999-1 date de publication en ligne : 26/10/2020 En ligne : https://doi.org/10.1007/s13595-020-00999-1 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96282 [article]

X-ray microdensitometry of wood: A review of existing principles and devices / Philippe Jacquin in Dendrochronologia, vol 42 (March 2017)  

Public [article]  inDendrochronologia > vol 42 (March 2017) . - pp 42 - 50 Titre : X-ray microdensitometry of wood: A review of existing principles and devices Type de document : Article/Communication Auteurs : Philippe Jacquin, Auteur ; Fleur Longuetaud, Auteur ; Jean-Michel Leban , Auteur ; Frédéric Mothe, Auteur Année de publication : 2017 Article en page(s) : pp 42 - 50 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes descripteurs IGN] dendrochronologie [Termes descripteurs IGN] densité du bois [Termes descripteurs IGN] rayon X [Termes descripteurs IGN] tomographie Résumé : (auteur) Wood microdensitometry is the analysis of radial variations of density at the annual or intra-annual growth ring level. Density is related to wood quality, biomass, carbon content, tree growth and climate. Wood microdensitometry is particularly used in dendrochronology and climatology studies. The present study focuses on X-ray based methods used in wood microdensitometry analyses and provides a review of the main available devices. An exhaustive review of 75 works published on this topic in 2014 and 2015 showed that film-based equipment is still commonly used. The three other most popular devices, SilviScan, Itrax and QTRS, are also based on X-ray radiography and deliver results with comparable accuracy, below 50 μm per pixel. X-ray tomography (CT) is still rarely used in wood densitometry. Medical CT scanners currently offer a lower accuracy (above 100 μm per pixel) that is insufficient in most cases for ring or intra-ring scales. Micro-CT scanners offer good performance at the cost of much longer acquisition and reconstruction times. Numéro de notice : A2017-893 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.dendro.2017.01.004 date de publication en ligne : 27/01/2017 En ligne : https://doi.org/10.1016/j.dendro.2017.01.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91887 [article]

Within-stem maps of wood density and water content for characterization of species: a case study on three hardwood and two softwood species / Fleur Longuetaud in Annals of Forest Science [en ligne], vol 73 n° 3 (September 2016)  

Public [article]  inAnnals of Forest Science [en ligne] > vol 73 n° 3 (September 2016) . - pp 601 - 614 Titre : Within-stem maps of wood density and water content for characterization of species: a case study on three hardwood and two softwood species Type de document : Article/Communication Auteurs : Fleur Longuetaud, Auteur ; Frédéric Mothe, Auteur ; Meriem Fournier, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 601 - 614 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes descripteurs IGN] Abies alba [Termes descripteurs IGN] acer pseudoplatanus [Termes descripteurs IGN] analyse discriminante [Termes descripteurs IGN] caractérisation [Termes descripteurs IGN] espèce végétale [Termes descripteurs IGN] Fagus sylvatica [Termes descripteurs IGN] pseudotsuga menziesii [Termes descripteurs IGN] quercus (genre) [Termes descripteurs IGN] teneur en eau de la végétation [Termes descripteurs IGN] tomographie [Termes descripteurs IGN] tronc [Termes IFN] densité du bois Résumé : (auteur) Key message : Variability and interrelations between wood density, water content, and related properties were analyzed by CT scanning of five species. Relative water content of lumens is proposed as the best complement to basic specific gravity for discrimination of species with respect to their functioning. Context : X-ray computed tomography (CT) is an efficient tool for analysis of wood properties related to density and water content all along a tree stem. Basic specific gravity, an inherent property of the wood material, is well known and widely used in wood sciences. Aims : The first aim of this study was to describe a method for mapping a set of wood properties within a tree stem. The second objective was to analyze the relations among these properties and to identify the one that offers the best information in addition to basic specific gravity for discrimination of species. Methods : Wood discs were collected at various heights along a tree stem. We used a method consisting of comparing the CT images of the discs in the green state and after oven drying. Finally, 10 variables were computed for 115 trees of five temperate species: green, oven-dry, and basic specific gravities; moisture content; relative water content; relative water content of lumens; and fractions of air, water, free water, and cell walls. Results : Maps of wood properties summarizing the radial and vertical variations were obtained, allowing us to highlight species-specific patterns. The five species were discriminated best when plotted in the plane defined by basic specific gravity and relative water content of lumens. Conclusion : The proposed method is original and simple enough to process large samples. Because it correlated less with basic specific gravity than with moisture content, relative water content of lumens was selected for species characterization. This is the first study of such wood properties at this fine scale within a tree stem, simultaneously and for a substantial number of trees of five species including both hardwoods and softwoods. Numéro de notice : A2016-710 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article En ligne : http://dx.doi.org/10.1007/s13595-016-0555-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82088 [article]

Variations in the natural density of European oak wood affect thermal degradation during thermal modification / Joël Hamada in Annals of Forest Science [en ligne], vol 73 n° 2 (June 2016)  

Public [article]  inAnnals of Forest Science [en ligne] > vol 73 n° 2 (June 2016) . - pp 277 - 286 Titre : Variations in the natural density of European oak wood affect thermal degradation during thermal modification Type de document : Article/Communication Auteurs : Joël Hamada, Auteur ; Anélie Pétrissans, Auteur ; Frédéric Mothe, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 277 - 286 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes descripteurs IGN] bois [Termes descripteurs IGN] économie industrielle [Termes descripteurs IGN] effet thermique [Termes descripteurs IGN] industrie forestière [Termes descripteurs IGN] quercus (genre) [Termes descripteurs IGN] sylviculture [Termes descripteurs IGN] tomographie Résumé : (auteur) Key message : Thermogravimetric analysis, performed on small samples of earlywood (EW) or latewood (LW), indicated that earlywood is more susceptible to thermal degradation than latewood. These results suggest a direct relationship between wood density (which depends on the EW/LW ratio and indirectly on silviculture) and the response of wood during thermo-modification processes. Context: One of the main difficulties in developing thermo-modified wood products at an industrial scale lies in the difficulty of obtaining consistent products with a stable quality (durability, dimensional stability, color). This may be due either to the thermal treatment process itself or to inter- or intra-specific heterogeneity of wood properties. Aims: We investigated the effect of the natural variability of oak wood, particularly in density, on the degree of thermo-degradation during thermal treatments. Methods: X-ray computed tomography was used to assess the effect of initial wood density of oak boards on their thermo-degradation. Intra-ring wood density was estimated using thermogravimetric analysis and micro-densitometry. Results: X-ray CT did not allow establishment of a clear correlation between initial wood density and mass loss due to thermo-degradation, while thermogravimetric analysis, performed separately on earlywood and latewood samples, revealed a larger susceptibility to thermal degradation of the less dense earlywood samples compared to more dense latewood samples Conclusion: Initial wood density, which is directly controlled by the earlywood/latewood ratio modulated by silvicultural practices, directly influences thermo-degradation during thermal treatment. Initial wood density therefore appears to be a potential parameter influencing industrial thermal treatment processes. Numéro de notice : A2016-349 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article En ligne : http://dx.doi.org/10.1007/s13595-015-0499-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81060 [article]

Measurement of the annual biomass increment of the French forests, XYLODENSMAP project [diaporama] / Jean-Michel Leban (2016)    

Public Titre : Measurement of the annual biomass increment of the French forests, XYLODENSMAP project [diaporama] Type de document : Article/Communication Auteurs : Jean-Michel Leban , Auteur ; Jean-Christophe Hervé , Auteur ; Jean-Daniel Bontemps , Auteur ; Fleur Longuetaud, Auteur ; Frédéric Mothe, Auteur ; Philippe Jacquin, Auteur Congrès : Modelling Wood Quality, Supply and Value Chain Networks-Wood QC (12 - 18 juin 2016), Commanditaire Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN Année de publication : 2016 Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] arbre (flore) [Termes descripteurs IGN] base de données localisées [Termes descripteurs IGN] biomasse forestière [Termes descripteurs IGN] densité du bois [Termes descripteurs IGN] inventaire forestier national (données France) [Termes descripteurs IGN] puits de carbone [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) In the context of climatic change an increasing attention is paid to the ability of forests to store more carbon as increasing carbon sequestration by forests is equivalent to reducing emissions the release of carbon to the atmosphere. Estimating the quantity of carbon sequestered in the forests is usually based upon the National Forest Inventory statistical measurements. These measurements are converted in estimates of the annual forest increments that in turn are converted in annual biomass increments by the means of models and of average basic density values depending of the availability of wood density data bases. The wood density is very variable among species and is dependant of the annual rings anatomical structure (ring porous, semi-ring porous, diffuse porous, non-porous) and of the growth conditions of the trees (genetic origin, stand age and structure, management, and climate). These different sources of variability of the wood density are not yet taken into account for forests carbon accounting. The objective of this project is to measure the wood density variations on all the thirty thousand trees measured during one year by the technicians of the French National Forest Inventory. A new low cost method was developed for the processing of all the collected increment cores. The increments cores are stored in alveolar polycarbonate plates, dried and scanned with one medical Xray scanner. For each increment core the width of the last five rings was measured on the field and the corresponding wood density obtained by the scanner and a new informatics program. This method is tested for the first time in France and it will provide a new xylotheque and an original wood density data set for all the French tree species measured by the National Forest Inventory. We will present preliminary results for the new measurement proxy of the annual forest biomass increments, illustrate the perspective to analyze the biomass increments in relation with the forests stand structure and with the geographical climatic conditions and discuss the interest to measure on the same samples other wood properties than wood density. Numéro de notice : C2016-016 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : FORET Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans date de publication en ligne : 17/06/2017 En ligne : https://www.researchgate.net/publication/304037000_Measurement_of_the_annual_bio [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84600

Documents numériques

en open access Measurement of the annual biomass increment of the French forests Adobe Acrobat PDF

Estimation harmonisée du volume de tige à différentes découpes / Christine Deleuze in Rendez-vous techniques, n° 44 (printemps 2014) 

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Estimer le volume total d’un arbre, quelles que soient l’essence, la taille, la sylviculture, la station / Christine Deleuze in Rendez-vous techniques, n° 44 (printemps 2014) 

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Les coefficients d’expansion pour déduire différents volumes de branches à partir de volumes de tige / Fleur Longuetaud in Rendez-vous techniques, n° 39-40 (Hiver-printemps 2013) 

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Measuring wood density by means of X-ray computer tomography / Charline Freyburger ; Fleur Longuetaud ; Frédéric Mothe ; Thiéry Constant ; Jean-Michel Leban in Annals of Forest Science, Vol 66 n° 8 (December 2009)  

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