Effects of thinning on diameter, heartwood, density and drying defects of Gmelina arborea

Vallejos, Jonathan; Moya, Róger; Serrano, Rafael Espejo

doi:10.4067/s0718-221x2015005000034

Cited by 11 publications

(11 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Some researchers have found that the wood density increase with age or distance from pith (Bonneman 1980, Boyce andKaiser 1961, Farmer andWilcox 1966). This is supported by the fact that the juvenile wood is usually known to be of the lower density than the mature wood (Dadswell 1958, Zobel and Buijtenen 1989, Lachenbruch et al 2011, Vallejos et al 2015. The wood density changes in the present experiment may be due to the trees which have entered the wood maturity phase and thus displayed a corresponding increase in wood density.…”

Section: Resultssupporting

confidence: 60%

“…Also, the higher density species tend to have stronger modulus of elasticity (low stiffness) and bending strength than lower density species (Zobel and Buijtenen 1989). Numerous studies (Johnson 1942, Dadswell 1958, Okkonen et al 1972, Zobel and Buijtenen 1989, Lachenbruch et al 2011, Vallejos et al 2015 have shown that that the shrinkage influences on wood stiffness and dimensional stability. These strong property gradients lead to warping and twisting of timber.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Empirical statistical model for predicting wood properties of Paulownia fortunie: Part 1: Physical and biometrical properties

Hassankhani¹,

Kord²,

Pourpasha³

2015

Maderas, Cienc. tecnol.

View full text Add to dashboard Cite

This paper describes the development of model to predict the within-tree variation of wood density, shrinkage, fiber length, fiber diameter and cell wall thickness from pith-to-bark and bottom-to-top, using data collected from a 13-year-old paulownia (Paulownia fortunie) stand where trees were planted in an experimental plantation in Iran. The sample disks were taken from each tree to examine the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness variation from pith to bark at 5, 25, 50 and 75% of the total tree height. The study was laid out in a randomized complete block design. Linear prediction model were developed using longitudinal direction (bottom-to-top) and radial direction (pith-to-bark) indices as explanatory variables. The results indicated that, the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness, considerably changes from pith to bark and from the base upwards. Based on the final model, it was found that the physical and biometrical properties were significantly influenced by longitudinal and radial directions. The model equation were based on the model used to describe the within-tree variation in the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness of Paulownia, and is functions of radial and longitudinal directions.

show abstract

Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Empirical statistical model for predicting wood properties of Paulownia fortunie: Part 1: Physical and biometrical properties

Hassankhani¹,

Kord²,

Pourpasha³

2015

Maderas, Cienc. tecnol.

View full text Add to dashboard Cite

show abstract

“…The thinning intensity is 70%, which has an effect on wood density and drying defects (Vallejos et al 2015). The average initial MC of the wood was above 60%, as shown in Figure 1.…”

Section: Methodsmentioning

confidence: 90%

Stress characteristics and stress reversal mechanism of white birch (Betula platyphylla) disks under different drying conditions

Zhao

et al. 2016

Maderas, Cienc. tecnol.

View full text Add to dashboard Cite

Drying stress is the main cause for the generation of drying cracks in wood disks during drying, which limits the processing and utilization of this valuable material. For this study, white birch disks with one trunk and a thickness of 30 mm were dried under three different drying conditions: 1) a very slow drying process preventing the generation of a radial moisture content (MC) gradient, 2) a drying process with slowly increasing temperature leading to a radial MC gradient, with a higher MC in the heartwood, and 3) the same heat drying process but the wood disks were partly covered with a thin plastic film prior to the drying process leading to a reversed radial MC gradient, i.e., a higher MC in the sapwood. For each drying condition, the tangential elastic strain in the wood disks was investigated for a mean MC of 26%, 18% and 10%, respectively, as a function of the radial distance from the pith in order to predict the drying stress. Furthermore, the stress characteristics and stress reversal mechanisms in wood disks are discussed in this paper with the help of stress analysis sketches.

show abstract

“…Por otra parte, se observa que las propiedades físicas y energéticas de la biomasa de los clones varían principalmente por la edad, como suele suceder para G. arborea [24], [35]. Por ejemplo, el peso específico básico (Figura 1a), el poder calorífico y contenido de cenizas de fuste y ramas aumenta (Figura 2a-b, Cuadro 3) con la edad, pero en el caso de la densidad en condición verde (Figura 1b), contenido de cenizas (Cuadro 3) y cantidad de carbón (Figura 2c-d) de ramas y fuste, disminuyen con la edad.…”

Section: Discussionunclassified

“…En Centroamérica, G. arborea crece en sitios de diferente nivel de precipitación, temperatura y en suelos con niveles adecuados de calcio [23]. En el caso de Costa Rica, G. arborea es plantada en una alta variedad de sitios y el crecimiento de los árboles en plantaciones permite que en la actualidad su turno de corta sea inferior a 10 años [24]. En la producción de madera, G. arborea tradicionalmente se ha utilizado en densidades que van desde los 600-1200 árboles/hectárea con el objetivo de obtener madera para el mercado de las tarimas [25].…”

Section: Introductionunclassified

Propiedades de la biomasa de plantaciones de corta rotación de dos clones de Gmelina arborea Roxb en tres espaciamientos

Moya

2019

RFMK

Self Cite

View full text Add to dashboard Cite

El conocimiento de las propiedades de la biomasa proveniente de clones de Gmelina arborea Roxb en cultivos energéticos en sistemas de corta rotación (SRC en inglés) en Costa Rica es limitado. Los primeros intentos están basados en el uso de clones para la producción de madera, pero plantados en SRC. Así, el presente estudio tuvo como objetivo evaluar las propiedades físicas (peso específico, densidad y contenido de humedad), energéticas (poder calorífico, contenido de cenizas y materiales volátiles) y contenido de carbón de dos clones de G. arborea utilizados para la producción de madera, pero plantados en SRC bajo tres espaciamientos (1,0x1,0 m, 0,75x0,75 m y 1,0x0,5 m), entre 6 y 24 meses de edad. Los resultados muestran que el peso específico básico fue de entre 0,30 a 0,38, la densidad verde de 0,9 a 1,0 g/cm3, el contenido de humedad entre 40 y 70%, el poder calorífico de 18.000 a 20.000 kJ/kg, la cantidad de cenizas fue menor a 4,8% y el contenido de volátiles de entre un 70 a 86%, mientras que el contenido de carbono disminuyo con la edad. Se observaron diferencias entre los dos clones en edades tempranas, pero estás tienden a desaparecer con el aumento de la edad, en especial a la edad de 24 meses, que es cuando se pretende que la plantación sea cosechada, siendo esto una ventaja ya que se tiene una biomasa uniforme si los dos clones son utilizados.

show abstract

Effects of thinning on diameter, heartwood, density and drying defects of Gmelina arborea

Cited by 11 publications

References 14 publications

Empirical statistical model for predicting wood properties of Paulownia fortunie: Part 1: Physical and biometrical properties

Empirical statistical model for predicting wood properties of Paulownia fortunie: Part 1: Physical and biometrical properties

Stress characteristics and stress reversal mechanism of white birch (Betula platyphylla) disks under different drying conditions

Propiedades de la biomasa de plantaciones de corta rotación de dos clones de Gmelina arborea Roxb en tres espaciamientos

Contact Info

Product

Resources

About