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X-ray microdensitometry of wood: A review of existing principles and devices / Philippe Jacquin in Dendrochronologia, vol 42 (March 2017)
[article]
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 Projets : ARBRE / AgroParisTech (2007 -) Article en page(s) : pp 42 - 50 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] dendrochronologie
[Termes IGN] densité du bois
[Termes IGN] rayon X
[Termes IGN] tomographieRésumé : (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
in Dendrochronologia > vol 42 (March 2017) . - pp 42 - 50[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, vol 73 n° 3 (September 2016)
[article]
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 IGN] Abies alba
[Termes IGN] Acer pseudoplatanus
[Termes IGN] analyse discriminante
[Termes IGN] caractérisation
[Termes IGN] densité du bois
[Termes IGN] espèce végétale
[Termes IGN] Fagus sylvatica
[Termes IGN] Pseudotsuga menziesii
[Termes IGN] Quercus (genre)
[Termes IGN] teneur en eau de la végétation
[Termes IGN] tomographie
[Termes IGN] troncRésumé : (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 DOI : 10.1007/s13595-016-0555-4 Date de publication en ligne : 20/05/2016 En ligne : https://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
in Annals of Forest Science > vol 73 n° 3 (September 2016) . - pp 601 - 614[article]Allometric models for estimating tree volume and aboveground biomass in lowland forests of Tanzania / Wilson Ancelm Mugasha in International journal of forestry research, vol 2016 ([01/08/2016])
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Titre : Allometric models for estimating tree volume and aboveground biomass in lowland forests of Tanzania Type de document : Article/Communication Auteurs : Wilson Ancelm Mugasha, Auteur ; Ezekiel Edward Mwakalukwa, Auteur ; Emannuel Luoga, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : 13 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] allométrie
[Termes IGN] biomasse aérienne
[Termes IGN] densité du bois
[Termes IGN] modèle numérique
[Termes IGN] Tanzanie
[Termes IGN] volume en boisRésumé : (auteur) Models to assist management of lowland forests in Tanzania are in most cases lacking. Using a sample of 60 trees which were destructively harvested from both dry and wet lowland forests of Dindili in Morogoro Region (30 trees) and Rondo in Lindi Region (30 trees), respectively, this study developed site specific and general models for estimating total tree volume and aboveground biomass. Specifically the study developed (i) height-diameter (ht-dbh) models for trees found in the two sites, (ii) total, merchantable, and branches volume models, and (iii) total and sectional aboveground biomass models of trees found in the two study sites. The findings show that site specific ht-dbh model appears to be suitable in estimating tree height since the tree allometry was found to differ significantly between studied forests. The developed general volume models yielded unbiased mean prediction error and hence can adequately be applied to estimate tree volume in dry and wet lowland forests in Tanzania. General aboveground biomass model appears to yield biased estimates; hence, it is not suitable when accurate results are required. In this case, site specific biomass allometric models are recommended. Biomass allometric models which include basic wood density are highly recommended for improved estimates accuracy when such information is available. Numéro de notice : A2016--110 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1155/2016/8076271 En ligne : http://dx.doi.org/10.1155/2016/8076271 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84741
in International journal of forestry research > vol 2016 [01/08/2016] . - 13 p.[article]Variations in the natural density of European oak wood affect thermal degradation during thermal modification / Joël Hamada in Annals of Forest Science, vol 73 n° 2 (June 2016)
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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 : [Termes IGN] bois
[Termes IGN] densité du bois
[Termes IGN] effet thermique
[Termes IGN] industrie forestière
[Termes IGN] Quercus (genre)
[Termes IGN] sylviculture
[Termes IGN] tomographie
[Vedettes matières IGN] ForesterieRésumé : (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 DOI : 10.1007/s13595-015-0499-0 Date de publication en ligne : 16/07/2015 En ligne : https://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
in Annals of Forest Science > vol 73 n° 2 (June 2016) . - pp 277 - 286[article]Investigating the possible impact of atmospheric CO2 increase on Araucaria araucana wood density / Paulina E. Pinto in European Journal of Forest Research, vol 135 n° 2 (April 2016)
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Titre : Investigating the possible impact of atmospheric CO2 increase on Araucaria araucana wood density Type de document : Article/Communication Auteurs : Paulina E. Pinto, Auteur ; Jean-Daniel Bontemps , Auteur ; Jean-Claude Pierrat, Auteur ; Tony Franceschini, Auteur ; Pierre Gelhaye, Auteur ; Jean-Claude Gégout, Auteur ; Jean-Michel Leban , Auteur Année de publication : 2016 Article en page(s) : pp 389 - 401 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Environnement
[Termes IGN] Araucaria araucana
[Termes IGN] Chili
[Termes IGN] Cordillère des Andes
[Termes IGN] dendrométrie
[Termes IGN] densité du bois
[Termes IGN] forêt tempérée
[Termes IGN] puits de carboneRésumé : (auteur) Our aim was to investigate the possible enhancing role of long-term atmospheric CO2 increase on wood density as an essential component of biomass sequestration. We therefore assessed the long-term evolution of wood density over pre-industrial and contemporary periods, in a regional context free of management practices, atmospheric deposition and with restricted climatic change. Dominant trees of Araucaria araucana were sampled in 37 stands distributed throughout its natural distribution over temperate forests of the Chilean Andes Cordillera. Mean ring density (MRD) at 1.30 m was measured by X-ray micro-densitometry. A third-century MRD chronology was built after MRD standardisation by the effects of cambial age and radial growth, simultaneously estimated from a statistical model from rings of the pre-industrial period (1700–1850) to avoid any temporal bias. The age-alone standardised MRD chronology showed restricted fluctuations ranging between 2.0 and 3.2 % over the last three centuries. Multi-decennial fluctuations between ring width and MRD were found qualitatively synchronous and opposed. Accordingly, MRD fluctuations were removed with the age and growth standardisation, highlighting the absence of a historical wood density trend at constant ring size over the whole period. Over the most recent decades however, a slight increase in density was identified, with loss of synchronisation to radial growth. The absence of a long-term signal in wood density of A. araucana, in a context of restricted anthropogenic influence, differs markedly from reports of significant decreases in the Northern Hemisphere. We conclude as part of the analysis done that until now, increasing atmospheric CO2 unlikely would have an impact in wood density. Numéro de notice : A2016--085 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10342-016-0942-2 Date de publication en ligne : 03/03/2016 En ligne : http://doi.org/10.1007/s10342-016-0942-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84570
in European Journal of Forest Research > vol 135 n° 2 (April 2016) . - pp 389 - 401[article]Measurement of the annual biomass increment of the French forests, XYLODENSMAP project [diaporama] / Jean-Michel Leban (2016)PermalinkStand density, tree social status and water stress influence allocation in height and diameter growth of Quercus petraea (Liebl.) / Raphaël Trouvé in Tree Physiology, vol 35 n° 10 (October 2015)PermalinkWhen tree rings behave like foam : moderate historical decrease in the mean ring density of common beech paralleling a strong historical growth increase / Jean-Daniel Bontemps in Annals of Forest Science, Vol 70 n° 4 (June 2013)PermalinkMeasuring wood density by means of X-ray computer tomography / Charline Freyburger in Annals of Forest Science, Vol 66 n° 8 (December 2009)PermalinkComparing volume growth in pure and mixed stands of Pinus sylvestris and Quercus pyrenaica / Miren del Río in Annals of Forest Science, Vol 66 n° 5 (July - August 2009)PermalinkHigh resolution temporal variation in wood properties in irrigated and non-irrigated Eucalyptus globulus / David M. Drew in Annals of Forest Science, Vol 66 n° 4 (June 2009)Permalink