• Journal of Forest and Environmental Science
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• 제28권4호
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• pp.263-267
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• 2012

Characteristics of charcoals manufactured in each temperature as 400, 600 800, 1,000 and $1,200^{\circ}C$ were examined. Sapwood and heartwood of Quercus variabilis that one of major species in charcoal materials were used for this experiment. Charcoal density was decreased highly 38-60% compared with wood density and density of sapwood was slightly decreased but heartwood was not changed with increasing carbonization temperature increase. Weight loss of sapwood and heartwood charcoal increased as carbonization temperature increases, and there is no difference between sapwood and heartwood charcoal. Refining degree of sapwood and heartwood charcoal was zero in charring over $800^{\circ}C$. Moisture and ash of sapwood and heartwood charcoal in each carbonization temperature were not differed between sapwood and heartwood. Volatile of sapwood charcoal was slightly higher than that of heartwood, and decreased as carbonization temperature increases. As the carbonization temperature increased, fixed carbon of sapwood and heartwood charcoal increased. Calorific values of charcoal prepared at $600^{\circ}C$ were 7,200-7,300 cal/g and then decreased slightly as carbonization temperature increased.

• Journal of the Korean Wood Science and Technology
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• 제23권1호
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• pp.28-34
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• 1995

Korean pine(Pinus koraiensis S. et Z.) is an economically important species in Korea because it will be harvested largely within next 20~30 years. The purpose of this study was to investigate changes in green moisture content, specific gravity and shrinkage in the stems of a Korean pine trees to provide fundamental information for technical processes. The followings are the results of this study. 1. There were about 110% differences in the heartwood and sapwood' green moisture contents (heartwood=59.5%; sapwood=170.6%). 2. There were no significant differences in average volumetric shrinkage between heratwood and sapwood, even though there were significant differences in moisture contents between them. Therefore, moisture content did not significantly influence on the shrinkage. 3. There was no significant relationship between height and shrinkage in heartwood. However, in the sapwood, shrinkage was highly correlated with the height. 4. Shrinkage levels were the most significant in south-bound direction and least significant in north-bound direction in both heartwood and sapwood. 5. There was a positive correlation between specific gravity and shrinkage in the sapwood. However, no such a relationship was found in the heartwood.

• Journal of the Korean Wood Science and Technology
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• 제15권2호
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• pp.67-78
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• 1987

This study was designed to investigate the effect of board thickness and ring angle on the characteristics including internal check. ring failure, surface check, end check, collapse, thickness shrinkage and width shrinkage of press-drying. The exprimental materials of 6mm-. 9mm- and 12mm-thick board were taken from heartwood and sapwood of oak (Quercus acutissima Carr.) respectively. And boards were numbered according to position in the log(No. 1 to No. 4 for heartwood :md No. 9 for sapwood). Press-drying was at $145^{\circ}C$ platen temperature and 3.5kg/$Cm^2$ platen pressure. The results of this study were summarized as follows. 1. Drying rates for sapwood materials were greater than those for heartwood materials. And drying rates for thinner materials were greater than those for thicker materials. 2. The thinner boards were. the severer surface checking developed in the heartwood materials, and surface checking for heartwood materials had no tendency in board position for the same thickness. Sapwood materials were completely free from surface checking. 3. End checking for heartwood materials had no tendency in board position. The greater deviation of ring angle from perfectly edge-grained was, the severer and checking developed in the sapwood materials. But end checking did not occur in 6mm-thick sapwood materials. 4. The greater deviation of ring angle from perfectly edge-grained was, the severer end checking developed for heartwood and sapwood materials. As board thickness increased, maternal checking developed more severely for heartwood and sapweed materials. 5. For heartwood materials, ring failure, reduced with increasing deviation of ring angle from perfectly edge-grained except 12mm-thick material and showed no significant difference attributable to board thickness. Sapwood materials were completely free from ring failure. 6. For heartwood and sapwood materials, collapse was slight and showed no significant differences attributable to both board thickness and board position. 7. As deviation of ring angle from perfectly edge-grained increased, shrinkage of board thickness decreased for heartwood and sapwood materials. 8. Shrinkage of board width showed no significant differences attributable to both board thickness and board position for heartwood and sapweed materials.

• 한국가구학회지
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• 제22권3호
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• pp.199-207
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• 2011

Examined the color of ten species of Korean broadleaf trees were experimented based on $L^*a^*b^*$ values and color difference (${\Delta}E^*ab$) between sapwood and heartwood, in order to analyze and determine the color, a critical visual and decorative factor of the broadleaf trees that can be used for making woodcraft and furniture. According to the result, the entire sapwood and heartwood, except the heartwood of Populus tomentiglandulosa, showed positive value in whiteness, redness, and yellowness and therefore contained yellow and red. None of the species showed color difference between sapwood and heartwood that was trace (0~0.5), slight (0.6~1.5), or very much; whereas Populus maximowiczii showed noticeable color difference (1.5~3.0); Salix koreensis, Betula platyphylla var japonica, Carpinus laxiflora, and Castanea crenata, appreciable and Populus tomentiglandulosa, Juglans mandshurica, Betula schmidtii, Alnus japonica, and Quercus variabilis, much. The color characteristics of heartwood and sapwood of the ten Korean broadleaf tree species studied in this research can be used as basic data for woodcraft or furniture production, especially when replacing foreign woods with Korean ones, and also contribute to convergence researches for science, engineering, and design fields.

• Journal of the Korean Wood Science and Technology
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• 제24권3호
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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.

• 임산에너지
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• 제22권1호
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• pp.1-7
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• 2003

우리나라의 주요 조림수종으로 앞으로 대경재로 대량벌목 이용될 낙엽송의 가공와 이용을 위한 기초적 자료인 생재함수율, 비중 및 수축율의 수간내의 변동을 심ㆍ변재로 나누어 조사, 검토하였다. 심ㆍ변재간 생재함수율, 비중 및 수축율은 유의차를 보였다. 생재함수율의 방사방향 분포는 심재에서는 거의 일정한 함수율을 보이다가 변재에서 높아지는 현상을 보였고, 지상고 분포는 심재에서는 높아짐에 따라 함수율이 작아지고, 변재에서는 커지는 것으로 나타났다. 방향에 따른 비중의 차는 심ㆍ변재 모두 없었으며, 지상고에 따라서는 변재는 없었으나 심재에서는 차이를 나타냈다. 방향 및 지상고에 따른 수축율의 차는 대부분 심ㆍ변재에서 별다른 유의차가 관찰되지 않았으나, 변재 일부방향에서 북쪽방향의 수축율이 남쪽방향의 수축율보다 높은 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제44권6호
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• pp.880-889
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• 2016

To evaluate the resistance of wood to decay caused by fungi, sapwood and heartwood of red pine (Pinus densiflora) and sapwood and heartwood of larch (Larix kaempferi) were conducted. Wood samples were immersed for 96 h in pyroligneous liquor. Then, the brown-rot fungus, Fomitopsis palustris, was used to examine the decay resistance of red pine and larch. Weight and density of wood from the all conditions increased after immersion treatment. Weight loss after decay resistance test was also dropped with a immersion treatment. The lowest weight loss indicated at immersion-treated heartwood of larch. Immersion treatment using pyroligneous liquor effectively increased the resistance of wood to decay caused by fungi.

• Journal of the Korean Wood Science and Technology
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• 제52권1호
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• pp.13-30
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• 2024

Swietenia mahagoni is one of the commercial timbers in Indonesia. Mahogany heartwood is an important characteristic as it relates to the natural durability and aesthetics of the wood. Lipophilic extractives are known to be involved in the heartwood formation process. Therefore, this study aims to determine the lipophilic compounds associated with heartwood formation. The n-hexane extract from sapwood and heartwood samples (1 to 5 years) was analyzed by gas chromatography-mass spectrometry. The results showed that the content of n-hexane extract ranged from 0.76% to 2.45% based on dry wood. The main group of compounds identified in the lipophilic fraction consisted of sterols (β-sitosterol, stigmasterol, campasterol, and cyclolaudenol), fatty acids (palmitic, oleic, linoleic, and stearic acid), and hydrocarbons (pentadecane, 1-octadecane, hexadecane, cyclotetracosane, cycloeicosane, and cyclooctacosane) after heartwood formation. In addition, the hydrocarbon fraction was the largest, followed by sterols, fatty acids, and 1-heneicosanol. In the radial variation, the distribution of fatty acids was greater in the sapwood than in the heartwood (4-year-old). However, the reverse pattern was found at the age of 5 years. The lipophilic fraction was generally more abundant in the heartwood compared to the sapwood, especially at 5 years of age, with much higher levels than when the heartwood was forming (4 years). These findings show that when the heartwood formation begins, the lipid composition was not fully metabolized at the beginning of heartwood formation compared to 5-year-old trees.

• Journal of the Korean Wood Science and Technology
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• 제47권1호
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• pp.8-20
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• 2019

This study was conducted to analyze the pore structure of Yellow poplar. Cross-sectional surfaces of heartwood and sapwood of Yellow poplar (Liriodendron tulipifera) were observed by SEM, and the true density of the heartwood, intermediate wood and sapwood were measured by gas pycnometery, while gas permeability and pore size of heartwood, intermediate wood and sapwood were measured by capillary flow porometery. The pores were classified as through pore, blind pore and closed pore. It was determined that the permeability was increased due to the content and size of through pore being increased although the total porosity of specimen showed slight difference from pith to bark. The content of through pore porosity was 33.754 % of heartwood and 47.810 % of sapwood, showed an increasing trend from pith to bark, however, those for the blind pore porosity and closed pore porosity were 27.890 % and 19.492 % for heartwood and 19.447 % and 4.660 % for sapwood, showed a decreasing trend from pith to bark. The max pore size of specimens was increased by about 5 times from $5.927{\mu}m$ to $31.334{\mu}m$, and mean flow pore size was increased by about 315 times from $0.397{\mu}m$ to $12.437{\mu}m$ from pith to bark.

• Journal of the Korean Wood Science and Technology
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• 제19권4호
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• pp.27-33
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• 1991

Three kinds of specimens(radiata pine sapwood, radiata pine heartwood and whemlock heartwood) were dried at four temperature levels (30, 40, 50 and $60^{\circ}C$) in an emvironmental chamber. Unsteady-state diffusion coefficients were calculated from obtained drying fates by using infinite slab equation for first half of sorption and interval diffusion equation for second half of sorption. Activation energies for moisture diffusion in wood were calculated from the diffusion coefficients obtained at four temperatures. In most cases diffusion coefficients for radial movement were higher than those for tangential movement. Activation energy differences between sapwood and heartwood weren't significant for radial movement, but were significant for tangential movement. Most activation energies calculated from drying rates were lower than heat of water condensation(about 11,000cal/mole). Specially the avenge activation energy for sapwood tangential movement was only 5,000cal/mole.