Contribution à l'interprétation anatomique des microvariations de la densité du bois de douglas

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Douglas fir rings anatomy by image analysis: interpretation of intra ring wood density microvariations

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Image analysis of ring anatomy: interpretation of intra-ring microvariations in wood density

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Relationships between the intra-ring wood density assessed by X-ray densitometry and optical anatomical measurements in conifers. Consequences for the cell wall apparent density determination

The objective of this work is to compare anatomical measurements to wood density variations within annual rings of three major softwood species, Norway spruce, Scots Pine and Silver Fir. The six selected annual rings were sampled within a database of thousand microdensitometric profiles measured on wood samples collected in Finland and France. Each of the six studied annual rings represents one average profile of wood density for a given age class and age ring width. The dimensions of the tracheids are performed in the radial-tangential plane by using two different planimetric methods. The wood density profile within each ring is calculated simply by the mean of the tracheid dimensions and by using a constant value for the cell wall density. We have verified that the knowledge of the (i) tracheid geometry and (ii) the usually admitted value of the cell wall density allows us to calculate intra ring wood density profiles which are similar to the X-rays wood density profiles in terms of variations but very different in average. Thus it appears necessary to calibrate by using an apparent cell wall density varying inside the rings and being far weaker than the effective cell wall density of 1460 kg/m 3 as it is usually admitted in the literature.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Linking intra-tree-ring wood density variations and tracheid anatomical characteristics in Douglas fir (Pseudotsuga menziesii (Mirb.) Franco)

In this study, a geometric approach was used in order to model the relationships between intra-tree-ring wood density variations and tracheid anatomical characteristics. One Douglas fir was studied in detail. Anatomical slides of 256 tree-rings were compared with the corresponding density profiles. Radial and tangential tracheid diameters decline from earlywood to latewood by 50% and 15%, respectively. At the same time, radial and tangential cell-wall thicknesses increase by 110% and 132%, respectively. Wood density exhibits an S-shape profile with a slight decrease of 10% at the beginning of a ring and an increase of 212% thereafter. Model simulations showed that wood density increase is mainly due to cell-wall thickening in tangential and radial directions as well as cell size reduction in radial direction. Simulations also showed that the knowledge of tracheid anatomical characteristics is not sufficient to fully explain wood density decrease at the beginning of earlywood. © INRA, EDP Sciences, 2006.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Optical interpretation of intra ring density variations: The packing density question

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Evaluation of the wood quality of the forest resource in Douglas (Pseudotsuga menziesii (Mirb.) Franco). Preliminary study

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Cell wall measurements on thin cross sections by image analysis

Wood Fibre Cell Walls :Methods to study their formation, structure and properties. Schmitt, Grünwald, Ander, Barnett, Emons, Saranpää & Tschegg (eds) - EU/COSTinfo:eu-repo/semantics/publishe