Uniformity of wood density assessed from X-rays of increment cores

Echols, R. M.

doi:10.1007/bf00353377

Cited by 20 publications

(19 citation statements)

References 2 publications

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“…Mathematical approaches like the one presented in this paper could consider the ring-to-ring variation in the intra-ring wood density profiles. Despite the differences in the earlywood and latewood features defined by the two methods, the same trends and peaks are observed (figures [4][5][6]. This indicates that each of the two methods has its own merits.…”

Section: Earlywood-latewood Transitionmentioning

confidence: 72%

“…Woods with large differences between earlywood and latewood densities (e.g., larches) are not uniform, whereas woods with small differences between earlywood and latewood densities (e.g., poplars, birches) are uniform. Intra-ring wood density variation also determines the suitability of a wood for specific end-uses [4][5][6]. Uniform woods, for example, are preferred for veneer and panelboard manufacturing, whereas non-uniform woods are preferred for appearance products mainly because of the contrast between earlywood and latewood.…”

Section: Introductionmentioning

confidence: 99%

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Defining the transition from earlywood to latewood in black spruce based on intra-ring wood density profiles from X-ray densitometry

Koubaa

Zhang

Makni³

2002

Ann. For. Sci.

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-Defining the transition from earlywood to latewood in annual rings is an important task since the accuracy of measuring wood density and ring width components depends on the definition. Mork's index has long been used as an anatomical definition of the transition from earlywood to latewood. This definition is arbitrary and extremely difficult to apply to X-ray densitometry. For X-ray densitometry, a threshold density of between 0.40 to 0.55 g cm -3 , depending on species, has been chosen to differentiate between earlywood and latewood density, but this method has shortfall. Therefore, new methods need to be developed and integrated into the computational programs used to generate X-ray densitometry data. In this study, we presented a mathematical method. We modelled the intra-ring wood density profiles in 100 plantation-grown black spruce (Picea mariana (Mill.) B.S.P.) trees using high order polynomials. The correlation between the predicted and the measured densities is very high and highly significant. Based on this model, we define the transition from earlywood to latewood as the inflexion point. Results indicate that wood density at the earlywood-latewood transition point varies from juvenile to mature wood. This method could be easily integrated into any X-ray densitometry program and allows to compare individual rings in a consistent manner.transition / earlywood / latewood / X-ray densitometry / wood density / black spruce / modelling Résumé -Définition de la transition du bois initial au bois final chez l'épinette noire à partir des profiles de densité intra cernes obtenus par densimétrie aux rayons X. La précision de l'estimation des densités et des largeurs du bois initial et du bois final dans un cerne annuel dé-pend de la définition de la transition du bois initial au bois final. L'indice de Mork a longuement servi pour donner une définition anatomique à cette transition. Cette définition est arbitraire et difficile à appliquer en densimétrie aux rayons X. En général, un seuil de densité variant entre 0,40 à 0,55, dépendamment de l'essence, sert à différencier le bois initial du bois final. Cette méthode a certaines limites et d'autres méthodes doivent être développées et intégrées aux programmes de densimétrie aux rayons X. Nous avons utilisé une approche mathématique pour modé-liser les profiles de densité intra cernes dans 100 arbres d'épinette noire (Picea mariana (Mill.) B.S.P.). Le point d'inflexion de polynômes aux degrés élevés a servi pour définir la transition du bois initial au bois final. Les corrélations entre les densités mesurées et prédites sont élevées et significatifs. La transition du bois initial au bois final varie entre le bois juvénile et le bois adulte. Cette méthode est facile à intégrer dans les programmes de densimétrie aux rayons X et permet d'obtenir des comparaisons consistantes entre cernes annuels. transition / bois initial / bois final / densimétrie aux rayons X / densité du bois / épinette noire / modélisation

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Section: Earlywood-latewood Transitionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Defining the transition from earlywood to latewood in black spruce based on intra-ring wood density profiles from X-ray densitometry

Koubaa

Zhang

Makni³

2002

Ann. For. Sci.

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“…Echols (1973) attributed wood density uniformity degree as a limiting factor for the end use of the wood considering the effect in the sawing, drying, machining, gluing, f inishing and other wood quality. According to this, the log of E. cyclocarpum, with low uniformity in SG across transversal sections, may present better performance in sawing, drying, machining, gluing and finishing processes than the S. saman log.…”

Section: Discussionmentioning

confidence: 99%

Silviculture conditions and wood properties of Samanea saman and Enterolobium cyclocarpum in 19-year-old mixed plantations

Obando

Moya

2013

For. syst.

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Aim of study: The objective of this work is to examine wood properties of a mixed plantation of Samanea saman and Enterolobium cyclocarpum, combined with native species of Costa Rica.Area of study: Mixed plantation in dry tropical zone of Costa Rica.Material and Methods: It was measured by total diameter, heartwood, bark thickness, several physical wood properties (green density, specific gravity, volumetric, tangential and radial shrinkage and moisture content) and wood color.Main results: The largest of this diameter are reached when S. saman is planted with E. cyclocarpum, E. cyclocarpum and Swietenia macrophylla and Simarouba glauca. Meanwhile the largest total diameter and heartwood in E. cyclocarpum was found when this species is planted with Dalbergia retusa. Heartwood percentage, bark percentage, and some physical properties are not affected when S. saman or E. cyclocarpum are planted with other species. However, parameters of wood color were affected mixture plantation of S. saman or E. cyclocarpum with other species. The lowest difference between wood from mixed plantations and wood from trees growing in native forests is produced when S. saman is mixed with E. cyclocarpum, but this last species is mixed with Hymenaea courbaril and produced wood with the lowest difference in wood color compared to trees growing in the natural forest.Research highlights: S. saman and E. cyclocarpum tress planted in a mixed plantation produce variation in breast diameter, physical properties, heartwood percentage and wood color.Keywords: silvicultural condition; wood properties; tropical species; plantation species.

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“…No entanto, esses parâmetros ainda não eram satisfatórios (Ferrand, 1982), sendo proposto o Índice de Heterogeneidade (Harris, 1969), que foi amplamente aceito por longo período (Kanowski, 1985) por representar a variabilidade da densidade dentro de um mesmo anel de crescimento, persistindo as restrições iniciais para as espécies que têm tênue demarcação dos anéis de crescimento (Walker & Dobb, 1988 indicados, respectivamente, pela: (i) somatória após a ponderação das classes de densidade de superiores e inferiores à média dos dados totais de densidade (Echols, 1973) e (ii) calculado pelo volume de distribuição da densidade com referência à média ou mediana da densidade (Olson & Arganbrigth, 1977).…”

Section: A Densitometria De Raios X Na Determinação Da Densidade Da Munclassified

“…As variações da densidade da madeira de um anel de crescimento ou de uma seção transversal de amostra de madeira têm forte influência na qualidade de madeira (Echols, 1973) sendo mais importantes quando associadas às características anatômicas (Decoux et al, 2004).…”

Section: Variações No Perfil Da Densidade Da Madeira Por Densitometriunclassified

Variação da anatomia e da densidade básica da madeira de Gmelina arborea (Roxb.), em diferentes condições de clima e de manejo na Costa Rica

Roque¹,

Alonso²

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Uniformity of wood density assessed from X-rays of increment cores

Cited by 20 publications

References 2 publications

Defining the transition from earlywood to latewood in black spruce based on intra-ring wood density profiles from X-ray densitometry

Defining the transition from earlywood to latewood in black spruce based on intra-ring wood density profiles from X-ray densitometry

Silviculture conditions and wood properties of Samanea saman and Enterolobium cyclocarpum in 19-year-old mixed plantations

Variação da anatomia e da densidade básica da madeira de Gmelina arborea (Roxb.), em diferentes condições de clima e de manejo na Costa Rica

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