Characterization of strength properties of branchwood and stemwood of some tropical hardwood species

Okai, Reynolds; Frimpong-Mensah, Kwasi; Yeboah, Dominic

doi:10.1007/s00226-004-0232-x

Cited by 27 publications

(22 citation statements)

References 2 publications

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“…Berat jenis merupakan parameter terbaik dalam memprediksi sifat kekuatan kayu (Panshin dan de Zeeuw, 1980). Beberapa penelitian yang menghubungkan berat jenis dan sifat mekanika kayu di spesies lainnya memperoleh hasil yang bervariasi (Stalnaker dan Harris, 1989;Okai et al, 2004;Koch, 1964). Beberapa faktor yang menyebabkan lemahnya korelasi antara berat jenis dan kekuatan kayu antara lain keberadaan silika atau endapan mineral lainnya dalam sel, kadar resin, struktur jari-jari atau panjang serat (Okai et al, 2004), kadar lignin atau sudut mikrofibril dalam dinding sel (Koch et al, 2000;Bhat et al, 2001 …”

Section: Penyiapan Sampelunclassified

Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul IV. Sifat Mekanika Kayu

Marsoem¹,

Prasetyo²,

Sulistyo³

et al. 2015

Jurnal Ilmu Kehutanan

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Section: Penyiapan Sampelunclassified

Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul IV. Sifat Mekanika Kayu

Marsoem¹,

Prasetyo²,

Sulistyo³

et al. 2015

Jurnal Ilmu Kehutanan

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show abstract

“…Branch wood has also been used to estimate SG W (Swenson and Enquist 2008), but even if branch wood approximates trunk sapwood SG, it may not be representative of trunk heartwood (Okai et al 2004). In addition, for species with radial increases in SG, initial branch wood SG may be similar to that of the outer or the inner trunk wood xylem, depending on the age and height at which the branch is initiated (Rueda and Williamson 1992).…”

Section: Other Estimators Of Sg Wmentioning

confidence: 99%

Testing a Novel Method to Approximate Wood Specific Gravity of Trees

Wiemann¹,

Williamson²

2012

Forest Science

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Wood specific gravity (SG) has long been used by foresters as an index for wood properties. More recently, SG has been widely used by ecologists as a plant functional trait and as a key variable in estimates of biomass. However, sampling wood to determine SG can be problematic; at present, the most common method is sampling with an increment borer to extract a bark-to-pith core-a difficult task requiring considerable physical effort and sometimes repeated borings to hit the pith, with potential to damage the trunk of small trees. Here, we test a novel sampling method that reduces the effort to obtain an adequate increment core and results in less wood extracted from the tree. The Wiemann approximation predicts the point along a radius at which the wood SG equals the disk cross-sectional SG. When SG changes linearly across the radius, the point of approximation is at two-thirds of the radial distance. As a test, we compare SG at various points along the radius with the true SG of the disk. At all points except the point of approximation (i.e., at two-thirds of the radial distance), wood SG differed significantly from the true cross-sectional mean SG, whereas at two-thirds of the radial distance, the wood SG did not differ significantly from the tree mean SG for a group of 128 tropical trees and 25 temperate trees that had been sampled bark to pith. Overall, the method shows promise in that wood SG of a tree may be estimated accurately and without bias by boring the tree only to the point of approximation, that is, one-sixth of the trunk diameter. However, boring to one-sixth of the diameter provides an unbiased estimate of SG only if radial variation in SG is a linear function of radial distance. A limitation of the method is that an initial subsample of trees must be bored to determine the pattern of radial variation in a species before the approximation can be applied to other individuals. FOR. SCI. 58(6):577-591.

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“…Moisture content distributions in branchwood and stemwood of Aningeria robusta and Terminalia ivorensis were investigated by Okai, R. et al [1,2] in order to determine the suitability of branchwood as raw material for the downstream processing sector. The effects of moisture content on the strength properties of branchwood have also been reported by Okai, R. et al [3]. Moisture content distributions and their effects on strength properties of branchwood, stemwood and rootwood of iroko and emire trees have been reported by Amoah, M. et al [4].…”

mentioning

confidence: 68%

Effects of Grain Angle on Reproducibility and Accurate Measurement of Moisture Content of Wood Samples Using a Pin-Style Moisture Meter

Okai¹

2016

JESE-B

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Studies were conducted on the effects of grain angle on reproducibility and accurate measurement of moisture content of four wood samples using a pin-style moisture meter. The wood samples were partitioned into four quadrants and moisture contents were measured along the grain direction in the first and second quadrants from 0 degree to 150 degrees insteps of 30 degrees. Experimental results indicated that the average moisture content remained constant as the grain angle increased. Repeated measurements of moisture content at different grain angles or points on the wood surface showed similar patterns of variation. Within-point standard deviations of the moisture contents were greater than between-point standard deviations. A non-destructive method of measuring moisture content at the same location or point on the wood surfaces could not be proposed because of the high variation of moisture content when repeated measurements were taken at the same point. Instead, accurate measurements of moisture content could be obtained at random positions within a radius of 30 mm from the point of intersection of the moisture content axis and the grain angle.

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Characterization of strength properties of branchwood and stemwood of some tropical hardwood species

Cited by 27 publications

References 2 publications

Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul IV. Sifat Mekanika Kayu

Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul IV. Sifat Mekanika Kayu

Testing a Novel Method to Approximate Wood Specific Gravity of Trees

Effects of Grain Angle on Reproducibility and Accurate Measurement of Moisture Content of Wood Samples Using a Pin-Style Moisture Meter

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