• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.12-17
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• 1996

This study was carried out to investigate some mechanical properties for wood rational utilization of heartwood and sapwood in radiata pine according to basic density, ring width and proportion of latewood which were grown in New Zealand. This result were summarized as follow: Heartwood showed 35.78(MPa) of the compression strength parallel to the grain while sapwood showed 42.08(MPa). The modulus of rupture in static bending was higher in sapwood showing 86.12(MPa) than in heartwood 72.99(MPa) Heartwood had 7.38(GPa) for the modulus of elasticity in static bending and sapwood 8.17(GPa). As the basic density and proportion of latewood increased: compression strength parallel to the grain, MOR and MOE in static bending had a tendency to increase. As ring width increased, the mechanical properties decreased.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.695-704
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• 2016

Physical and mechanical properties of Korean red pine wood grown in Anmyeon-do, Taean-gun, Chungcheongnam-do and Sogwang-ri, Uljin-gun, Gyeongsangbuk-do, Korea were measured and each relationships between them were analyzed. The ring width and latewood proportion along radial axis in Korean red pine at two-regions were measured by collecting the growth core of stands with age class V and IX. The ring width in Korean red pine at two-regions decreased with increasing cambium age. The average ring widths in age class V and IX in Anmyeon-do and Sogwang-ri were 2.865 mm, 1.705 mm, 4.764 mm, and 2.228 mm, respectively. The ring widths in Anmyeon-do were measured from 23% to 40% smaller than Sogwang-ri. The latewood proportion was negatively related with the ring width of Korean red pine at two-regions. The relationship between physical and mechanical properties of specimens for compressive and bending strength tests were analyzed with simple regression analysis. The relationship between latewood proportion and oven-dry density were positive and statistically significant. The relationship between latewood proportion and mechanical properties was slightly positive and not statistically significant, except the specimens for bending strength test of Anmyeon-do. The relationship between oven-dry density and mechanical properties was positive. It was just statistically significant in the specimens of Sogwang-ri. The compressive and bending strengths of Anmyeon-do and Sogwang-ri were 51.3 MPa, 80.5 MPa, 37.7 MPa, and 63.7 MPa, respectively. The strength difference between two-regions was determined to due to difference of ring width and latewood proportion by age class.

• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.9-17
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• 1999

This study was carried out to get some basic information on mechanical properties of Korean Lepidobalanus for the rational utilization of their woods, Five species of Quercus variabilis, Q. aliena, Q. serrata, Q. mongolica, Q. acutissima belonging to Lepidobalanus were investigated in this research. Relationship of anatomical characteristics with bending strength was analyzed using stepwise regression technique. All possible combination of 21 independent variables were regressed on bending strength. The summarized results in this study were as follows: 1) In the proportion of wood structural elements, the most important factors on bending strength appeared to be proportion of wood fiber in earlywood in Q. variabilis and Q. serrate, proportion of ray in earlywood in Q. aliena, proportion of vessel in earlywood in Q. mongolica and proportion of wood fiber in latewood in Q. acutissima, respectively. 2) In the other quantitative anatomical characteristics, the most important factors on bending strength appeared to be number of pore per $1mm^2$ in latewood in Q. variabilis, microfibril angle in Q. aliena and Q. mongolica, length of wood fiber in Q. serrata and height of uniseriate ray in Q. acutissima, respectively.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.63-69
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• 1998

This study was carried out to get some basic information on mechanical properties of Korea Lepidobalanus for rational utilization of wood. Five species of Quercus variabilis, Q. aliena, Q. serrata, Q. mongolica, Q. acutissima belong to Lepidobalanus were investigated in this research. Relationship of anatomical characteristics to compression strength parallel to grain was analyzed using stepwise regression technique. All possible combination of 21 independent variables were regressed on compression strength parallel to grain. The summarized results in this study were as follows: I. In the proportion of wood structural elements, the factors that had the greatest influence on compression strength parallel to grain appeared to be proportion of ray in earlywood in Q. variabilis and Q. acutissima, proportion of wood fiber in latewood in Q. aliena and Q. serrata and proportion of vessel in earlywood in Q. mongolica respectively. 2. In the size of wood element and its structure, the factors that had the greatest influence on compression strength parallel to grain were microfibril angle in Q. variabilis, Q. serrata and Q. mongolica and length of wood fiber in Q. aliena and Q. acutissima.

• Journal of Forest and Environmental Science
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• v.8 no.1
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• pp.21-33
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• 1992

This study was performed to investigate the hardness of wood related to the wood surface, sap and heartwood, early and latewood, specific gravity, annual ring width and moisture content on major Korean tree species such as Pinus koraiensis, Abies holophylla, Larix leptolepis and Quercus valiabilis. The results were summarized as follows: 1. The arithmetic mean values of wood hardness on cross section were respectively $8.0kg/mm^2$ on Quercus valiabilis, $7.4kg/mm^2$ on Larix leptolepis, $5.1kg/mm^2$ on Pinus koraiensis and $4.7kg/mm^2$ on Abies hollophylla. 2. Generally hardness of wood on cross section was greater than the others and the proportion of cross section hardness to radial was respectively 2.8 on Quercus valiabilis, 2.6 on Larix leptolepis, 3.8 on Pinus koraiensis, and 4.1 on Abies holophylla and that proportion was tend to be decrease as specific gravity increased. 3. It was recognized that the hardness of sap and heartwood was different from each of the tree species and generally heartwood hardness was somewhat greater than sapwood. 4. Generally latewood hardness with in a ring was greater than earlywood and the proportion of earlywood hardness to latewood decreased as specific gravity increased. 5. The relations between hardness of wood and specific gravity show a high positive correlation on all sample tree species. 6. The values of hardness decreased with increasing annual ring width. 7. Hardness of wood on Abies holophylla was greatest in oven dried wood and it was decreased as moisture content increased, but not changed with moisture content abve F.S.P.. The proportion of oven dried wood hardness to green are respectively 3.0 on cross, 2.4 on radial and 1.9 on tangential section.

• Journal of the Korean Wood Science and Technology
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• v.33 no.1 s.129
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• pp.38-47
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• 2005

Compression, lateral, and opposite woods in a branch of Pinus parviflora S. et Z. were described and compared in the qualitative anatomical aspects through light and scanning electron microscopy. Tracheid transition from earlywood to latewood in the compression wood appeared to be relatively more gradual than in the opposite or lateral wood. Growth ring width and proportion of latewood were thought to be greater in the compression wood than in the lateral or opposite wood. The latewood tracheids of compression wood in transverse surface were mostly round, differently from those of lateral and opposite woods with square to angular shapes. Also, intercellular spaces, helical cavities and checks, and slit-like pit apertures were observed only in the compression wood tracheids. Cross-field pitting in the compression wood appeared not to be used as diagnostic guide because of their severe alteration from normal fenestriform or window-like type to cupressoid to taxodioid types. In tangential surface, fusiform rays in the compression wood were wider but lower than those in the lateral wood or opposite wood. In conclusion, compression wood was different from lateral and opposite woods but lateral and opposite woods were almost identical in qualitative anatomical features.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.525-534
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• 2017

The study aims to observe the cellular anatomical properties of Dahurian larch and Japanese larch for the species identification. In addition, other factors - the ring width, tracheid length, density, and strength - were compared and analyzed to clarify their physical and mechanical properties. To the end, three Dahurian larch trees and three Japanese larch trees by each diameter class were collected as specimens from Jeongseon-eup, Jeongseon-gun, Gangwon-do, to conduct a stem analysis. It was found that the average stand age, average diameter at breast height, and average tree height of three Dahurian larch trees and Japanese larch trees were 74 years and 51 years, 442 mm and 352 mm, and 26.1 m and 20.8 m, respectively. The cellular anatomical difference between Dahurian larch and Japanese larch can be usually found by spiral thickening, considering that it doesn't occur in Dahurian larch at all, while rarely does in the ray tracheids of Japanese larch. However, in this study, spiral thickening was not observed in the radial section of Japanese larch. The average annual growth diameters measured at 1.2 m-height of Dahurian larch and Japanese larch were 5.167 mm and 5.954 mm, respectively. Meanwhile, arboreal growth of Japanese larch was observed to be higher than that of Dahurian larch. In the physical properties test, it was measured that the latewood proportion and oven-dry density of Dahurian larch with low annual diameter growth were higher than those of Japanese larch, while the mechanical properties of Dahurian larch wood were measured 2-7% higher than those of Japanese larch wood. The data obtained from this study are expected to be used as the basic reference for species identification between Dahurian larch and Japanese larch by DNA analysis.