The Apparent Density of Wood in Non-Swelling Liquids

Christensen, G. N.; Hergt, H. F. A.

doi:10.1515/hfsg.1968.22.6.165

Cited by 12 publications

(5 citation statements)

References 3 publications

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“…The assumed WSD f (1.46 g/cm 3 ) did not differ significantly from the published data (e.g. Christensen and Hergt, 1968;Wilfong, 1966). Nonetheless, it might have been slightly different from the unknown initial WSD of the tested archaeological wood.…”

Section: Resultsmentioning

confidence: 41%

“…Lower wood substance densities determined in helium or a solvent which does not cause wood swelling have been noted and explained many times in the case of research on fresh wood (e.g. Christensen and Hergt, 1968;Kollmann and Cöté, 1968;Wilfong, 1966). However, usually these differences are at least 0.050 g/cm 3 .…”

Section: Resultsmentioning

confidence: 94%

“…For fresh wood the values obtained in water are distinctly higher than the values obtained in helium or organic solvents (e.g. Christensen and Hergt, 1968). In spite of the differences in density of the main chemical components of cell walls (Beall, 1972) and differences in chemical composition of various wood species (Fengel and Grosser, 1975), in handbooks on wood science it is assumed that the density of fresh wood substance changes only within a narrow range and is independent of the type of tested wood.…”

Section: Introductionmentioning

confidence: 97%

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Evaluation of the state of preservation of waterlogged archaeological wood based on its physical properties: basic density vs. wood substance density

Babiński

Izdebska-Mucha

Waliszewska

2014

Journal of Archaeological Science

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The state of preservation of waterlogged archaeological wood was evaluated on the basis of the maximum moisture content (MMC), the basic density (BD) and the wood substance density (WSD) determined in water and helium. The degree of wood degradation was compared under the criteria: the loss of wood substance (LWS) and the loss of wood substance density (LWSD). Studies were conducted on the wood samples differing in species, degree of degradation, age and place of origin. The physical properties of wood were determined for the material containing mineral compounds and the material without minerals. The properties of the latter, in which the minerals are replaced by water, were calculated from the mass and volume of the wood containing minerals as well as the content and density of the ash obtained after burning the sample. The study revealed the effect of minerals on the tested parameters and wood degradation indices. A strong relationship between BD and MMC was confirmed for both the wood containing minerals and without them, by contrast a substantially weaker correlation between BD and WSD was observed. It was found that the assessment of the state of wood preservation conducted on the basis of LWS and LWSD yielded different results. In addition, it was revealed that both indices of wood degradation might be unreliable. The main drawback of the LWS-based assessment is associated with a wide range of basic density of fresh wood. In turn, the LWSD mainly indicates the changing ratio of the carbohydrates/lignin content, but fails to provide information on the loss of wood substance. This may hinder the comparison of the wood sampled from different sites and subjected to different decay mechanisms. Nevertheless, the WSD-based assessment of the state of preservation of waterlogged archaeological wood might be a valuable complementary method to the BD-and/or MMC-based assessment, which is routinely carried out in many conservation centers.

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Section: Resultsmentioning

confidence: 41%

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 97%

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Evaluation of the state of preservation of waterlogged archaeological wood based on its physical properties: basic density vs. wood substance density

Babiński

Izdebska-Mucha

Waliszewska

2014

Journal of Archaeological Science

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“…Non-polar molecules such as benzene, carbon tetrachloride, and heptane are not very soluble in wood cell walls and all swelled dry wood less than 0.01% on the time-scale of an hour [133], but after 8 days benzene swelling of 0.2%-0.3% was observed. Mantanis and coworkers reported dry wood swelling rates of non-polar solvents up to five orders of magnitude slower than water and, therefore, allowed 100 days of soaking before measuring 1.2% swelling in carbon tetrachloride and 0.85% in octane [129].…”

Section: Diffusion In Dry Wood Cell Wallsmentioning

confidence: 99%

Effects of Moisture on Diffusion in Unmodified Wood Cell Walls: A Phenomenological Polymer Science Approach

Jakes

Hunt

Zelinka

et al. 2019

Forests

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Despite the importance of cell wall diffusion to nearly all aspects of wood utilization, diffusion mechanisms and the detailed effects of moisture remain poorly understood. In this perspective, we introduce and employ approaches established in polymer science to develop a phenomenological framework for understanding the effects of moisture on diffusion in unmodified wood cell walls. The premise for applying this polymer-science-based approach to wood is that wood polymers (cellulose, hemicelluloses, and lignin) behave like typical solid polymers. Therefore, the movement of chemicals through wood cell walls is a diffusion process through a solid polymer, which is in contrast to previous assertions that transport of some chemicals occurs via aqueous pathways in the cell wall layers. Diffusion in polymers depends on the interrelations between free volume in the polymer matrix, molecular motions of the polymer, diffusant dimensions, and solubility of the diffusant in the polymer matrix. Because diffusion strongly depends on whether a polymer is in a rigid glassy state or soft rubbery state, it is important to understand glass transitions in the amorphous wood polymers. Through a review and analysis of available literature, we conclude that in wood both lignin and the amorphous polysaccharides very likely have glass transitions. After developing and presenting this polymer-science-based perspective of diffusion through unmodified wood cell walls, suggested directions for future research are discussed. A key consideration is that a large difference between diffusion through wood polymers and typical polymers is the high swelling pressures that can develop in unmodified wood cell walls. This pressure likely arises from the hierarchical structure of wood and should be taken into consideration in the development of predictive models for diffusion in unmodified wood cell walls.

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“…A mean value of 1460 kg/m³ which may be considered as the dry cell wall density value, and also as the density of the dry wood substance (as the dry cell wall would be essentially non porous [34,35,39,40,42,44]) may be brought out for conifers [4,19,38,39,[43][44][45].…”

Section: Apparent Density Of the Cell Wallmentioning

confidence: 99%

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

Decoux

Varcin²,

Leban³

2004

Ann. For. Sci.

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-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/m³ as it is usually admitted in the literature.wood density / wood anatomy / Picea abies / Pinus silvestris / Abies alba Résumé -Variations intra-cerne de densité du bois et mesures optiques des caractéristiques anatomiques de résineux. Conséquences pour la détermination de la densité apparente de paroi. L'objectif de ce travail est comparer des mesures anatomiques à des mesures de variations de densité du bois à l'intérieur de cernes annuels pour trois essences résineuses importantes, l'épicéa commun, le sapin pectiné et le pin sylvestre. Les cernes sélectionnés sont choisis dans un échantillon de plusieurs milliers de cernes prélevés dans des arbres en France et en Finlande. Chaque cerne étudié représente pour une essence le profil moyen de densité d'une classe d'âge compté depuis la moelle et d'une classe de largeur de cerne. Les caractéristiques géométriques des trachéides sont mesurées par deux méthodes planimétriques différentes dans le plan radial-tangentiel. Le profil de densité du bois est calculé simplement à partir des dimensions des trachéides et de la densité de la matière ligneuse. Pour que le profil calculé de densité du bois corresponde au profil obtenu par microdensitométrie nous avons montré qu'il est nécessaire faire varier le facteur de calibration, appelé densité apparente de la paroi cellulaire, à l'intérieur des cernes avec des valeurs bien plus faibles que 1460 kg/m³, la valeur habituellement utilisée dans la littérature. densité du bois / anatomie / Picea abies / Pinus silvestris / Abies alba

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The Apparent Density of Wood in Non-Swelling Liquids

Cited by 12 publications

References 3 publications

Evaluation of the state of preservation of waterlogged archaeological wood based on its physical properties: basic density vs. wood substance density

Evaluation of the state of preservation of waterlogged archaeological wood based on its physical properties: basic density vs. wood substance density

Effects of Moisture on Diffusion in Unmodified Wood Cell Walls: A Phenomenological Polymer Science Approach

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

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