• 한국가구학회지
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• 제21권1호
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• pp.72-82
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• 2010

The objective of this study is to identify the species of 17 wooden Buddhist statues of the late Joseon Dynasty (the 17th and 18th century) in Jeollado, southwestern region of Korea. The bodies of statues were made of Ginkgo (Gingko biloba L.: 88%) and alder (Alnus spp.: 12%). The hands of statues were alder(64%), willow (Salix spp.: 27%) and Ginkgo(9%). The bottoms of hollow bodies were covered all with Japanese red-pine (Pinus densiflora S. et Z., 'sonamu') panels. The main species of statue body, Ginkgo tree was known to be introduced to Korea from China with Buddhism. The results indicated that Ginkgo trees of Korea in the 17th century had already become large and rich enough to be used for most of statues. Ginkgo wood has low shrinkage and even texture, which are crucial for carving sculptures. Alder and willow woods used for statue hands have fine and firm textures. The pedestals for these statues were also made of red pine wood. Red pine woods have rather high shrinkage and low hardness, but it is versatile woods strong enough to support heavy statues.

• Journal of the Korean Wood Science and Technology
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• 제37권6호
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• pp.497-504
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• 2009

본 연구에서는 국산 잣나무, 일본잎갈나무, 신갈나무 및 산벚나무 Polyethylene glycol (PEG) 처리재의 초기 흡, 탈착과정에서 중량, 함수율 및 치수변화의 특성을 검토하였다. 각 수종의 무처리재와 PEG 1000, 2000, 4000 처리재는 상대습도 20%, 65% 및 98% 조건에서 1주일 동안 조습시켰다. 그 결과, 초기 흡, 탈착과정에서 PEG 1000과 2000으로 처리한 잣나무, 일본잎갈나무 및 산벚나무재의 중량은 크게 증감하였지만, 신갈나무재는 거의 변화가 없었다. PEG처리에 의한 함수율은 신갈나무재를 제외한 3 수종에서 상대습도의 변화에 의해 다소 높게 나타났으나, 모든 수종에서 PEG처리에 의해 치수변화를 예방할 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.591-607
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• 2020

This study was aimed to investigate the changes of chemical composition of the volatile organic compounds (VOCs) emitted from red pine needles in the process of needle abscission or senescence. The VOCs in intact, senescent, and litter red pine needle samples were analyzed by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS). And then, multivariate statistical interpretation of the processed data sets was conducted to investigate similarities and dissimilarities of the needle samples. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to investigate the dataset structure and discrimination between samples, respectively. From the data preview, the levels of major components of VOCs from needles were not significantly different between needle samples. By PCA investigation, the data reduction according to classification based on the chlorophyll a / chlorophyll b (Ca/Cb) ratio were found to be ideal for differentiating intact, senescent, and litter needles. The following OPLS-DA taking Ca/Cb ratio as y-variables showed that needle samples were well grouped on score plot and had the significant discriminant compounds, respectively. Several compounds had significantly correlated with Ca/Cb ratio in a bivariate correlation analysis. Notably, the litter needles had a higher content of oxidized compounds than the intact needles. In summary, we found that chemical compositions of VOCs between intact, senescent, and litter needles are different each other and several compounds reflect characteristic of needle.

• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.493-508
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• 2023

Round timber materials of 600 mm length, cut from large-cross-section round timber of red pine (Pinus densiflora S. et Z.) of 450 mm width and 4.2 m length, were prepared as the target of kiln drying in this study. After treating the target materials through end sealing (ES), end sealing - kerfing (ES-K), lateral sealing - end sealing - boring (LS-ES-B), or lateral sealing - partial end sealing (LS-PES), the effects of the treatment on the incidence of drying defects were determined. The target materials with exposed lateral surface and sealed cross surface were steamed at the initial temperature of 65℃ above the official pest control temperature of 56℃, followed by kiln drying toward the final temperature of 75℃. The target materials with sealed lateral surfaces, on the other hand, were dried at the initial temperature of 90℃ at almost the maximum temperature of conventional kiln drying, as there is no risk of early check formation caused by surface moisture evaporation. The final temperature was set at approximately 100℃. The drying time, taken for the target materials with initial moisture content of 70%-80% to reach the target moisture content of 19%, varied across treatment conditions. The measured drying time was 1,146 hours (approximately 48 days) for the timber with sealed cross surface and 745 hours (approximately 31 days) for the timber with sealed lateral surface, until the moisture content reached the target level. The formation of surface checks could not be prevented in the control and ES groups, but a definite preventive effect was obtained for the LS-ES-B and LS-PES groups.

• 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.

• 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.

• Journal of the Korean Wood Science and Technology
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• 제24권2호
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• pp.42-45
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• 1996

A residue from the newsprint waste was investigated as a filler in adhesive for bonding southern pine plywood. The residue was prepared by drying the wet residue to 8% moisture content and grinding the dry material using a laboratory Wiley mitt with a 75-${\mu}m$(200-mesh) screen. The residue was compared to a commercial filler commonly used in structural plywood adhesives. A total of 48 three-ply panels. 12.7mm nominal thickness and 0.3 by 0.3 m in size, were fabricated at two press times(4 and 5 min) and three assembly times(20, 40 and 60 min). Evaluations of the residue were carried out by performance tension shear tests after two 4-hour boil accelerated aging tests on plywood. The test results included tension shear strength and estimated wood failure values. All plywood made with the residue filler were comparable to the control-bonded plywood. These results indicate that residue from the newsprint waste streams would be suitable as filler for plywood adhesives.

• Journal of the Korean Wood Science and Technology
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• 제36권5호
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• pp.1-10
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• 2008

Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwood and southern yellow pine was investigated in this study. Brown rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolar were used to examine the decay resistance of the OSB. The OSB test specimens were colonized by brown and white rot fungal mycelium in both the brown and white-rot culture bottles after 8 and 12 weeks, respectively. The wood species and fungus type had the significant effects on the decay resistance. Brown rot decay was evident for all untreated southern pine and mixed hardwood controls. The white-rot decay, however, did not show significant weight loss at both species control samples. The incorporation of ZB and CB composites provides suitable protection against brown-and white-rot fungi. No significant weight loss was observed from the borate treated OSB.

• Journal of the Korean Wood Science and Technology
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• 제25권3호
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• pp.66-74
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• 1997

Liquid permeabilities of red oak and several softwoods were measured by the pressure bomb method and a modified liquid permeability method in order to investigate their efficacy. The effect of preboiling and prefreezing on wood permeability were also examined for both green and resaturated specimens. Regardless of some disadvantages these two methods were revealed as a handy tool for quick evaluation of the permeability of an unknown species. The permeabilities of the resaturated specimens increased when preboiled. but decreased when prefrozen. For green specimens, however, pre freezing increased permeability. The discrepancy of the pre freezing effect on two specimens partially attributes to their difference of initial permeabilities. For all species except radiata pine heartwood, the radii of the effective capillary pores, derived from the water potential equation, distribute from $0.42{\mu}m$ to $7.2{\mu}m$. Those of radiata pine heartwood are below $0.46{\mu}m$.

• Journal of the Korean Wood Science and Technology
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• 제41권5호
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• pp.399-405
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• 2013

This study demonstrates the utilization of light microscopy and Fast Fourier Transform-Peak Finding (FPF) method for microfibril angle (MFA) measurement from unstained sections of red pine (Pinus densiflora). To obtain an image with optimal contrast and resolution for MFA measurement, effects of numerical aperture (NA) of condenser lens and color filters were investigated. About 60% of NA of the maximum condenser NA produced an image with optimal contrast, but a color filter with short wavelength range (DAPI) created images with improved resolution. Manual angle measurement and the FPF method were applied to the image with optimal contrast for MFA measurement. The experimental results from the FPF method were considered to be more repeatable and less subjective than those from the manual angle measurement.