Éditeur(s) : London : H. Colburn and R. Bentley
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Collectivité territoriale de Martinique. Bibliothèque Schoelcher
Permalien : http://www.manioc.org/patrimon/SCH13082
SCH13082

Éditeur(s) : Québec : Comité permanent de la survivance française
Extrait de : Pour survivre vol. V, n°5
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : Communauté d'agglomération de La Rochelle. Médiathèque Michel-Crépeau
Permalien : http://www.manioc.org/patrimon/MMC16054-2
MMC16054-2

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of logging on taxonomic and functional diversity and composition in a tropical forest. 2. Twenty years after selective logging, we inventoried 4140 stems regenerating in logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3. We found no differences in taxonomic and functional richness among habitats, but logging gaps had significantly higher taxonomic and functional evenness. 4. Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in logging gaps was 6% less than in unlogged forests, leaves were 11% less tough and had 613% greater mineral nutrient concentrations. 5. Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand.
ISSN: 0021-8901

hal-01032420
https://hal.archives-ouvertes.fr/hal-01032420
DOI : 10.1111/j.1365-2664.2012.02164.x

Éditeur(s) : London : the bookfellers
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG17058
ADG17058

Éditeur(s) : New York : Francis P. Harper London : Gibbings
Siècle(s) traité(s) : 17
Droits : Domaine public
Provenance : Communauté d'agglomération de La Rochelle. Médiathèque Michel-Crépeau
Permalien : http://www.manioc.org/patrimon/MMC16037
MMC16037

Éditeur(s) : HAL CCSD Springer Verlag (Germany)
Résumé : International audience
*Context Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. *Aims The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties, by testing lesser-known species and categorizing sources of variability. *Methods Air-dry axial specific dynamic modulus of elasticity (E'/γ) and damping coefficient (tanδ) were measured on a wide sampling (1792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterizations. *Results Diversity at the specimens' level corroborates the "standard" relationship between tanδ and E'/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E'/γ ranges from 9 to 32 GPa and tanδ from 4×10-3 to 19×10-3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making.
Annals of Forest Science

hal-00808242
https://hal.archives-ouvertes.fr/hal-00808242
https://hal.archives-ouvertes.fr/hal-00808242/document
DOI : 10.1007/s13595-011-0166-z

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is < 2000 mm yr(-1) (water-limited forests) and to radiation otherwise (light-limited forests). On the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest productivity in a drier climate in water-limited forest, and in current light-limited forest with future rainfall < 2000 mm yr(-1).
ISSN: 1726-4170

hal-01557759
https://hal.univ-lorraine.fr/hal-01557759
https://hal.univ-lorraine.fr/hal-01557759/document
https://hal.univ-lorraine.fr/hal-01557759/file/bg-13-2537-2016.pdf
DOI : 10.5194/bg-13-2537-2016

Éditeur(s) : New-York : American anti-slavery society
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Collectivité territoriale de Martinique. Bibliothèque Schoelcher
Permalien : http://www.manioc.org/patrimon/SCH13214
SCH13214

Éditeur(s) : Londres : John Stockolale
Siècle(s) traité(s) : 18
Droits : Domaine public
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG17064
ADG17064

Résumé : Une étude de faisabilité de poutres en bois lamellé-collé a été menée en Guyane Française en utilisant les essences locales. Le but est de déterminer les paramètres de collage assurant la bonne résistance mécanique des assemblages par lamellation et par aboutage, nécessaires à la fabrication de poutres en bois lamellé-collé en climat tropical. Trois essences de bois abondantes de différentes densités ont été sélectionnées. Les adhésifs de types Mélamine-Urée-Formol et Résorcinol-Phénol-Formol ont été utilisées. Les paramètres de collage considérés sont : le grammage, le temps d’assemblage fermé et la pression.En utilisant les normes Européennes, plusieurs campagnes de tests ont été conduites sur des échantillons normalisés. Concernant le collage par lamellation, des tests élémentaires de délamination et de cisaillement des joints de colle ont été réalisés. Le test de délamination consiste en deux cycles d’immersion dans l’eau sous pression et de séchage, il induit de sévères variations d’humidité du bois susceptibles de créer des ouvertures des joints de colles. Le collage par aboutage est réalisé sur des poutres normalisées aboutées. Les entures sont obtenues grâce à un outillage standard communément utilisé pour les résineux. Les résultats ont mis en évidence l’influence des propriétés du bois et des paramètres de collage sur la résistance du joint et la résistance mécanique du produit. En effet, les paramètres du bois, tels que la densité, la rétractibilité et l’imprégnation, ont une forte influence sur le collage, en particulier sur la pression et le grammage nécessaires à la production d’un produit commercialisable. Il apparait qu’un bois de densité moyenne et poreux nécessite un grammage et une pression élevés comparé à un bois de densité élevée qui nécessite des valeurs moindres. Aussi, l’influence d’autres paramètres de fabrication, tels que le rabotage, l’encollage double face et simple face ainsi que l’épaisseur des lamelles, a été établie. Par contre il semblerait que le matériel communément utilisé pour l’aboutage des résineux n’est pas adapté aux feuillus tropicaux. En final, des paramètres de collage ont été validés pour la fabrication de lamellé-collé endémique en Guyane Française et une étude du coût de production d’une poutre lamellé-collé standard a identifié les conditions économiques d’une fabrication en Guyane Française.
A feasibility study of glued-laminated timber beams was carried out in French Guiana using local wood species. The aim of the study was to evaluate the gluing parameters that could ensure good mechanical properties for the manufactured glued-laminated beams in tropical climates. Three abundant wood species with different specific gravity were selected for the study. Melamine-Urea-Formaldehyde and Resorcinol-Phenol-Formaldehyde resins were used for gluing. The three gluing parameters considered are: adhesive spread rate, closing assembly time and gluing pressure.Using European standards, several laboratory tests were performed on normalized samples. The evaluation of a successful lamella’s gluing was done by using elementary tests of delamination and shearing. A delamination test consists of two cycles of water immersion at high pressure and drying which induces severe hygroscopic variation in wood thus causing joints opening. The finger-joints are made using a standard tool usually used for cutting softwoods. The performed tests revealed the influence of wood properties and the gluing parameters on the joint resistance and the mechanical properties of the product. Results show that wood properties such as specific gravity, shrinkage coefficient, and permeation, have a high degree of influence on the gluing step especially on the gluing pressure and on the adhesive spread rate needed to produce a commercial product. Furthermore, wood with medium specific gravity needs more adhesive and more pressure than the one with high specific gravity. Additionally, the effects of other manufacturing parameters, such as planning, double or simple side glue spreading and lamellae thicknesses, on the glue joint resistance were demonstrated. Finally, the common tools used for softwoods are not adapted to making the finger joints with tropical hardwoods.In conclusion, optimal gluing parameters for manufacturing glued-laminated timber beams in French Guiana were established and an economical study using standard glued-laminated timber beams revealed the economic conditions under which a successful manufacturing of these local beams can be implemented in French Guiana.

http://www.theses.fr/2011AGUY0484/document

Éditeur(s) : HAL CCSD Springer Verlag/EDP Sciences
Résumé : International audience
The vibration damping coefficient (tanδ) of wood is an important property for acoustical uses, including musical instruments. Current difficulties in the availability of some of the preferred species call for diversification, but this comes up against the lack of systematic damping coefficient data. * Keeping in mind the possible factors affecting tanδ, could we predict its variations between species, by using indicators that are either easily measured and/or readily available for many species? * Vibrational properties, equilibrium moisture content and colorimetric parameters were assessed on 94 wood types belonging to 76 species. Experimental results were then related to data on chemical contents and physical properties from the CIRAD database. The "standard" relationship between tanδ and specific modulus of elasticity (E'/ρ) explained only half of the variations. Deviations from this trend were correlated to extractives content, yet effects were not directly quantitative. Damping deviations were also correlated to colour and moisture-related properties, especially so with fibre saturation point. * By taking into account a combination of moisture-related properties, colour - or extractives content, and the "standard" relationship between tanδ and E'/ρ, we could propose simple predictive models which explain up to 89% of observed variations in tanδ between 48 species.
ISSN: 1286-4560

hal-00808338
https://hal.archives-ouvertes.fr/hal-00808338
https://hal.archives-ouvertes.fr/hal-00808338/document
https://hal.archives-ouvertes.fr/hal-00808338/file/Physico-chemical_indicators_Bremaud_al.pdf
DOI : 10.1051/forest/2010032

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Heartwood/sapwood profile and the tradeoff between trunk and crown increment in a natural forest: the case study of a tropical tree (Dicorynia guianensis Amsh., Fabaceae) Key message Sapwood area and the radial growth rate of the trunk follow the same pattern at breast height, with an initial increase and subsequent constant value, resulting from the increasing growth allocation toward the crown rather than tree decline. Heartwood area and heartwood volume in the trunk increase more rapidly after this shift occurs. Abstract Sapwood (SW) and heartwood (HW) are two functionally distinct classifications of wood in perennial stems for which quantities can vary greatly in tropical trees. Numerous positive correlations have been found between the radial growth rate (RGR) and SW quantity; however, variations in the SW/HW quantities have not been studied in light of the ontogenetic variation of RGR. Wood core sampling, intensive measurements of tree structure (number of branches, stem volumes), and radial growth monitoring were performed on an abundant and highly exploited tree species in French Guiana (Dicorynia guianensis) to investigate the relationship between RGR, SW/HW quantity, tree structure, and their variations on the course of a tree's ontogeny. SW area and RGR followed the same pattern of variation throughout tree development, both increasing first and reaching a steady state after 50 cm DBH (diameter at breast height). After this value, we observed a strong increase in both the HW area and HW volume increment, concomitant with a more rapid increase in crown volume. The stabilization of RGR for trees with DBH >50 cm was related not to a tree's decline but rather to an increasing wood allocation to the crown, confirming that RGR at breast height is a poor indicator of whole-tree growth for bigger individuals. We also confirmed that HW formation is an ontogenetic process managing SW quantity that is continuously and increasingly produced within the crown as the tree grows. This study highlights the effect of growth-mediated ontogenetic changes on the localization of water and carbohydrate storage within a tree, resulting from SW and HW dynamics throughout tree ontogeny.
ISSN: 0931-1890

hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003
https://hal.archives-ouvertes.fr/hal-01654003/document
https://hal.archives-ouvertes.fr/hal-01654003/file/Lehnebach%20et%20al.%E2%80%94Trees%202016-%20Own%20version.pdf
DOI : 10.1007/s00468-016-1473-7

Éditeur(s) : [S.l.] : Longmans
Résumé : Les Anglais dans les Indes occidentales. Gravures
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Université des Antilles. Service commun de la documentation
Permalien : http://www.manioc.org/patrimon/HASH1f8a614646a92da7410ddd
HASH1f8a614646a92da7410ddd

Éditeur(s) : HAL CCSD Elsevier
Résumé : Une approche par datations multiples a été menée sur les dépôts de sédiments de crue retrouvés dans les gorges du Gardon (Languedoc). Le plomb-210, le césium-137 et l’analyse géochimique des sédiments contaminés par les mines ont été utilisés pour reconstruire l’histoire des dépôts de crue. Cette approche a été combinée avec l’historique des crues du Gardon depuis 1890 pour affiner l’approche géochronologique. Au niveau de la cavité GG et de la terrasse GE les analyses ont permis d’illustrer les mécanismes d’érosion-redéposition pouvant perturber les séquences de sédiments. Les enregistrements des dépôts de sédiments de crue sont complets sur la terrasse GE située à 10 m au-dessus du lit mineur à partir de 1958, et incomplets auparavant. Sur la période 1880-1958, 25 crues ont eu un débit suffisant (>1450 m3/s) pour recouvrir la terrasse, alors que l’on recense seulement 5 à 6 crues depuis 1958 (pour un débit de submersion supérieur à 1700 m3/s). L’augmentation progressive du débit de submersion et la fréquence moindre d’inondation de la terrasse ont pu permettre sur la période récente la stabilisation de la couche de surface par la végétation et limiter l’érosion lors de crues importantes. Les enregistrements semblent complets dans la cavité GG située à 15 m au-dessus du lit mineur. La fréquence moindre de submersion à ce niveau plus élevé peut expliquer une meilleure stabilisation des dépôts de crue, rendus moins vulnérables à l’érosion. La datation au radiocarbone a été testée même si elle ne permet pas de dater avec précision les dépôts de crue des derniers siècles. Sur la terrasse GE, 80% des dates au carbone 14 sur charbon de bois sont beaucoup trop vieilles par rapport aux autres techniques de datation, ce qui peut s’expliquer par une remobilisation/déstockage de charbons de bois anciens. Les datations radiocarbone sur graines donnent de meilleurs résultats, car issues d’une production annuelle, plus facilement décomposable et moins sujette à des dépôts intermédiaires. Au final, il apparaît que la technique de datation par radiocarbone sur des charbons de bois retrouvés dans les séquences sédimentaires n’est pas fiable, alors qu’elle est la plus pratiquée en paléo-hydrologie. L’utilisation combinée du plomb-210, du césium-137, de l’analyse géochimique des sédiments et des informations sur les crues historiques a permis de discriminer et de dater les différents dépôts de crue de ce dernier siècle dans la cavité GG et la terrasse GE. / A multidating approach was carried out on slackwater flood deposits, preserved in valley side rock cave and terrace, of the Gardon River in Languedoc, southeast France. Lead-210, caesium-137, and geochemical analysis of mining-contaminated slackwater flood sediments have been used to reconstruct the history of these flood deposits. These age controls were combined with the continuous record of Gardon flow since 1890, and the combined records were then used to assign ages to slackwater deposits. The stratigraphic records of terrace GE and cave GG were excellent examples to illustrate the effects of erosion/preservation in a context of a progressively self-censoring, vertically accreting sequence. The sedimentary flood record of the terrace GE located at 10 m above the channel bed is complete for years post-1958 but incomplete before. During the 78-year period 1880-1958, 25 floods of a sufficient magnitude (> 1450 m3/s) have covered the terrace. Since 1958, however, the frequency of inundation of the deposits has been lower:only 5 or 6 floods in 52 years have been large enough to exceed the necessary threshold discharge (> 1700 m3/s). The progressive increase of threshold discharge and the reduced frequency of inundation at the terrace could allow stabilisation of the vegetation cover and improved protection against erosion from subsequent large magnitude flood events. The sedimentary flood record seems complete for cave GG located at 15 m above the channel bed. Here, the low frequency of events would have enabled a high degree of stabilisation of the sedimentary flood record, rendering the deposits less susceptible to erosion. Radiocarbon dating are used in this study and compared to the other dating techniques.Eighty percent of radiocarbon dates on charcoals were considerably older than those obtained by the other techniques in the terrace. On the other hand, radiocarbon dating on seeds provided better results. This discrepancy between radiocarbon dates on charcoal and seeds is explained by the nature of the dated material (permanent wood vs. annual production and resistance to degradation process). Finally, we showed in this study that although the most common dating technique used in paleoflood hydrology is radiocarbon dating, usually on charcoal preserved within slackwater flood sediments, this method did not permitus to define a coherent age model. Only the combined use of lead-210, caesium-137, and geochemical analysis of mining-contaminated sediments with the instrumental flood record can be applied to discriminate and date the recent slackwater deposits of the terrace GE and cave GG.
ISSN: 0169-555X

hal-01059669
https://hal.archives-ouvertes.fr/hal-01059669
https://hal.archives-ouvertes.fr/hal-01059669/document
https://hal.archives-ouvertes.fr/hal-01059669/file/ly2014-pub00040953.pdf
IRSTEA : PUB00040953

Éditeur(s) : London : printed by Richard Taylor
Résumé : 1823
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Ville de Pointe-à-Pitre. Réseau des bibliothèques
Permalien : http://www.manioc.org/patrimon/PAP11212
PAP11212

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé :  
Cross-species analyses of plant functional traits have shed light on factors contributing to differences in performance and distribution, but to date most studies have focused on either leaves or stems. We extend these tissue-specific analyses of functional strategy towards a whole-plant approach by integrating data on functional traits for 13 448 leaves and wood tissues from 4672 trees representing 668 species of Neotropical trees. Strong correlations amongst traits previously defined as the leaf economics spectrum reflect a tradeoff between investments in productive leaves with rapid turnover vs. costly physical leaf structure with a long revenue stream. A second axis of variation, the 'stem economics spectrum', defines a similar tradeoff at the stem level: dense wood vs. high wood water content and thick bark. Most importantly, these two axes are orthogonal, suggesting that tradeoffs operate independently at the leaf and at the stem levels. By simplifying the multivariate ecological strategies of tropical trees into positions along these two spectra, our results provide a basis to improve global vegetation models predicting responses of tropical forests to global change.
Ecology Letters

hal-01032142
https://hal.archives-ouvertes.fr/hal-01032142
DOI : 10.1111/j.1461-0248.2010.01517.x

Éditeur(s) : HAL CCSD Wiley
Résumé : Tropical forests contain an important proportion of the carbon stored in terrestrial vegetation, but estimated aboveground biomass (AGB) in tropical forests varies two-fold, with little consensus on the relative importance of climate, soil and forest structure in explaining spatial patterns. Here, we present analyses from a plot network designed to examine differences among contrasting forest habitats (terra firme, seasonally flooded, and white-sand forests) that span the gradient of climate and soil conditions of the Amazon basin. We installed 0.5-ha plots in 74 sites representing the three lowland forest habitats in both Loreto, Peru and French Guiana, and we integrated data describing climate, soil physical and chemical characteristics and stand variables, including local measures of wood specific gravity (WSG). We use a hierarchical model to separate the contributions of stand variables from climate and soil variables in explaining spatial variation in AGB. AGB differed among both habitats and regions, varying from 78 Mg ha−1 in white-sand forest in Peru to 605 Mg ha−1 in terra firme clay forest of French Guiana. Stand variables including tree size and basal area, and to a lesser extent WSG, were strong predictors of spatial variation in AGB. In contrast, soil and climate variables explained little overall variation in AGB, though they did co-vary to a limited extent with stand parameters that explained AGB. Our results suggest that positive feedbacks in forest structure and turnover control AGB in Amazonian forests, with richer soils (Peruvian terra firme and all seasonally flooded habitats) supporting smaller trees with lower wood density and moderate soils (French Guianan terra firme) supporting many larger trees with high wood density. The weak direct relationships we observed between soil and climate variables and AGB suggest that the most appropriate approaches to landscape scale modeling of AGB in the Amazon would be based on remote sensing methods to map stand structure.
ISSN: 1354-1013

hal-01374829
https://hal.archives-ouvertes.fr/hal-01374829
DOI : 10.1111/j.1365-2486.2011.02432.x
PRODINRA : 183370

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Grain deviations and high extractives content are common features of many tropical woods. We aimed at clarifying their respective impact on vibrational properties, referring to African Padauk (Pterocarpus soyauxii Taub.), a species selected for its interlocked grain, high extractives content, and uses in xylophones. Specimens were cut parallel to the trunk axis (L), and local variations in grain angle (GA), microfibril angle (MFA), specific Young's modulus (E'L/ρ, where r stands for specific gravity) and damping coefficient (tanδL), were measured. GA dependence was analyzed by a mechanical model which allowed to identify the specific Young's modulus (E'3/ρ) and shear modulus (G'/ρ) along the grain (3), as well as their corresponding damping coefficients (tanδ3, tanδG). This analysis was done for native and then for extracted wood. Interlocked grain resulted in 0-25° GA and in variations of a factor 2 in E'L/ρ and tanδL. Along the grain, Padauk wood was characterized, as compared to typical hardwoods, by a somewhat lower E'3/ρ and elastic anisotropy (E'/G'), due to a wide microfibril angle plus a small weight effect of extracts; and a very low tanδ3 and moderate damping anisotropy (tanδG/tanδ3). Extraction affected mechanical parameters in the order: tanδ3 ≈ tanδG > G'/ρ >> E'3/ρ. That is, extractives' effects were nearly isotropic on damping but clearly anisotropic on storage moduli.
ISSN: 0043-7719

hal-00544382
https://hal.archives-ouvertes.fr/hal-00544382
https://hal.archives-ouvertes.fr/hal-00544382/document
https://hal.archives-ouvertes.fr/hal-00544382/file/Identification_anisotropic_vibrational_properties_Bremaud_al.pdf
DOI : 10.1007/s00226-010-0348-0

Éditeur(s) : HAL CCSD
Résumé : Diffusion du document : INRA Antilles-Guyane, UMR ECOFOG, 97387 Kourou, Guyane (France) Diplôme : Master Recherche
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
La forêt tropicale guyanaise comporte entre 200 et 300 espèces d'arbres par hectare, alors qu'une forêt tempérée en compte environ une quinzaine. Les forêts tropicales humides sont des écosystèmes qui recèlent une des plus grandes biodiversités de la planète où les interactions entre les espèces et le milieu environnant atteignent des degrés de complexité élevés. Les arbres développent ainsi des stratégies souvent différentes, notamment celle du contrefil que nous avons cherché à décrire et à caractériser, lors de ce stage de Master 2ème année. Cette structure particulière du bois se retrouve dans une proportion importante dans les forêts tropicales. Elle consiste en une alternance d'hélices en S puis en Z de l'orientation longitudinale des fibres. Le stage s'est déroulé en grande partie en Guyane française, au sein de l'UMR « Ecologie des Forêts de Guyane » sur le site de Paracaïbo (Kourou). La première phase a été la prospection et la description du contrefil sur différentes espèces. Nous nous sommes ensuite intéressés au comportement mécanique en flexion statique et dynamique à différentes échelles. Enfin, au Laboratoire de Mécanique et Génie Civil de Montpellier, nous avons réalisé des mesures de l'angle des micros fibrilles afin de déterminer son évolution en fonction de l'angle du fil. Ainsi, prenant en compte les différentes échelles de description, nous avons mis au point un modèle permettant de prédire le comportement d'une poutre contre filée en flexion, connaissant la répartition du contrefil dans la section, la densité, et le module d'élasticité longitudinal orienté selon le fil du bois.
https://hal.archives-ouvertes.fr/hal-01189254

hal-01189254
https://hal.archives-ouvertes.fr/hal-01189254
PRODINRA : 19939

Éditeur(s) : HAL CCSD
Résumé :  
Improvement of wood quality related traits is currently hampered by costly chemical and technological assays and the necessity to wait until the trees are nearly mature to evaluate wood properties. The availability of a vast quantity of genomic data opens now a new avenue to identify early selection criteria based on molecular information and therefore increase selection efficiency. Association mapping is becoming a method of choice to identify QTN (quantitative trait nucleotide) that contribute to complex trait variation. The implementation of this approach requires on the one hand knowledge of the molecular mechanisms underlying trait variation and polymorphism within candidate genes, and on the other hand the availability of phenotypically well characterized genetic material. We are developing this strategy in the frame of the French maritime pine breeding program, an economically important forest tree species in the South Western Europe. About 500 trees from the breeding population were evaluated for wood physical and chemical properties through the analysis of 2,800 half-sib progenies and 1,500 clones in 8 field tests. These same trees are being genotyped at 185 SNPs obtained from the sequencing of 41 candidate genes, and an additional set of 200 eSNPs detected in 147 EST-contigs (to be used as control). Statistical association between the breeding values of the 500 trees and their respective genotypes will be tested using mixed models accounting for relatedness among individuals of the breeding population.
IUFRO-CTIA joint conference, "Adaptation, Breeding and Conservation in the Era of Forest Tree Genomics and Environmental Change"
Québec City, Canada

hal-01032075
https://hal.archives-ouvertes.fr/hal-01032075