• Journal of the Korean Wood Science and Technology
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• v.26 no.2
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• pp.1-5
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• 1998

Nail withdrawal tests were conducted on clear wood of radiata pine. Nails were driven into the earlywood and latewood zones of each specimen, and nail withdrawal tests were then performed. Nail withdrawal loads were strongly dependent on earlywood and latewood and on nail position. The average load values for nail withdrawal in both the tangential and longitudinal directions were higher for latewood than for earlywood. Linear and nonlinear regression analyses of nail withdrawal load with specific gravity showed no discernible differences. Good correlations were obtained between nail withdrawal load and specific gravity.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.57-66
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• 2004

To study the efficient usage of small diameter logs and woods containing defects such as knots, slope of the grain and decay, six types of finger-jointed woods with various finger profiles were made of poplar, pine and oak with different density. We investigated the effect of finger profile on static bending strength performances of finger-jointed woods. The efficiency of bending MOE, MOR and deflection showed the highest value in poplar finger-jointed wood with the lowest density of three species, and the lowest value in oak finger-jointed wood with the highest density of three species. The values markedly decreased with increasing finger pitch for finger-jointed wood glued with polyvinyl acetate (PVAc) resin for all tested species, whereas for the finger-jointed wood glued with resorcinol-phenol formaldehyde (RPF) resin, the influence of finger pitch on the efficiency of MOE was not found in all tested species, and those on the efficiency of MOR and deflection indicated the same trend as finger-jointed wood glued with PVAc resin in the case of pine and oak finger-jointed wood with higher densities. It was found that the values tended to decrease with increasing density of species on the whole and the desirable finger pitches were L (6.8 mm) for poplar, M (4.4 mm) for pine and S (3.5 mm) for oak in a view of economy. For finger-jointed wood glued with PVAc resin, the fitness between a tip and a root width of a pair of fingers δ of 0.5 mm indicated the highest efficiency of MOE for all species. And, the influence of δ on MOR was only found in oak finger-jointed wood glued with RPF resin and the desirable δ value for oak was 0.1 mm. However, it was found that the influence of δ on the strength performance was very small.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.335-342
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• 2016

In previous study, volatile organic compounds (VOCs) emission characteristics were highly affected by coating materials for wood finishing. Natural based coating materials showed that about 15~46% lower TVOC emission than typical products. In this study, long-term changes of VOCs emission characteristics from pine panel with three types of coating treatments were determined. Non-treated pine panel emitted $604.7{\mu}g/m^2{\cdot}h$ of TVOC that contained 66% of NVOC ($399.7{\mu}g/m^2{\cdot}h$) at 0 month. After 10 month, TVOC reduced 88% and 93% reduction on NVOC was observed. Natural oil and waterborne stain treated pine panel showed 61% and 77% lower TVOC, respectively, than non-treated pine panel. However, TVOC from finished pine panels showed higher TVOC emission than non-treated pine panel. All samples satisfied the VOC emission regulation (below $4,000{\mu}g/m^2{\cdot}h$) by Korean Ministry of Environment. Toluene emission regulation (below $80{\mu}g/m^2{\cdot}h$) was passed on all sample without varnish treated pine panel at 0 month. According to HB qualification standard for construction materials by Korea Air Cleaning Association (KACA), wood is not qualified to get the best tag due to high TVOC emission. At the 10 months, only non-treated pine panel could get the best tag of HB from KACA.

• Journal of the Korean Wood Science and Technology
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• v.44 no.4
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• pp.515-525
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• 2016

The Palsangjeon Pagoda is a five-story wooden building in the Beopjusa Temple area in the Songnisan national park in Chungcheongbuk-do, Korea. According to historical records, it was constructed in either AD 1605 or AD 1626. To specify the construction year more precisely, we took 41 wood samples for tree-ring analysis during repair actions in 2013; 28 from red pine (Pinus densiflora S. et Z.), 12 from oak (Quercus spp.), and 1 from fir (Abies spp.). The tree-ring boundaries became clearly visible by smoothing their cross-sectional surface and the tree-ring widths were measured under a stereo microscope. All tree-ring series were compared with each other to establish mean chronologies, which we then compared with local master chronologies established using tree rings collected from wooden elements of the Daeungjeon Hall which is the main building in the Beopjusa Temple area. As a result, it was verified that the red pines were felled in AD 1624 and in AD 1851. Moreover, it was verified that the oaks were also felled in AD 1624 based on cross-dating with the red pine chronology. We concluded that the Palsangjeon Wooden Pagoda was constructed in AD 1626, as mentioned in the historical record (Daeungdaekwangmyeongjeonbulsangki, 1630) and the letters on a purlin on the $4^{th}$ story, using oak and red pine felled in AD 1624 and repaired later on using red pine felled in AD 1851.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.666-675
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• 2020

This study investigated mechanical characteristics of pine trees in Yeongdong (Goseong-gun), Yeongseo (Hongcheon-gun), and Yeongnam (Bonghwa-gun) to define differences in the material quality among pine trees of the three regions. The compressive strength, hardness and shear strength of pine trees of each region were measured. There were no differences in the compressive strength of the juvenile woods among the regions, while the heartwood and sapwood in Bongwha generally showed the highest compressive strength followed by those in Hongcheon and in Goseong. The hardness of the cross-section of pines in Bonghwa was the highest, and in terms of the hardness of the radial and tangential sections, pines in Goseong topped the list.. There were no difference among heartwoods of each region in terms of the shear strength, but, but sapwood from Bonghwa had higher shear strength than those of the other two regions, which may be attributed to differences in tracheid length and microfibril angle among pines in each region. This study identifies the quality differences among pines of different region, and therefore, is expected to add value by helping choose the domestic pine tree material effectively and selectively, and also select a plus tree.

• Journal of the Korean Wood Science and Technology
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• v.40 no.5
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• pp.335-342
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• 2012

To prepare the eco-friendly fire retardant wood, Japanese red pine (Pinus densiflora), Hemlock (Tsuga heterophylla), and Radiata pine (Pinus radiata) were treated with inorganic chemicals, such as sodium silicate, boric acid, ammonium phosphate, and ammonium borate. Different combination and concentration of those chemicals were impregnated by vacuum/pressure treatment methods. The electron-beam treatment was used to increase the chemical penetration into the wood. The fire performance of the fire retardant treated wood was investigated. The penetration of chemicals into the wood was enhanced after electron beam treatment. Ignition time of the treated wood was the most effectively retarded by sodium silicate, ammonium phosphate, and ammonium borate. The most effective chemical combination was found at 50% sodium silicate and 3% ammonium borate, which satisfied flammability criteria for a fire retardant material in the KS F ISO 5660-1 standards.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.195-202
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• 2007

Milled Korean pine (Pinus densiflora) wood was used to evaluate its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled woods were pretreated with 1N NaOH, 1N $HNO_3$, and distilled water, respectively, to examine the effect of pretreatment. Within the tested pH range between 3 and 6, copper adsorption efficiency of NaOH-treated wood(96~99%) was superior to the $HNO_3$-treated wood(19~31%) and distilled water-treated wood(18~35%). The efficiency of copper removal by wood enhanced with increasing solution pH and reached a maximum copper ion uptake at pH 5~6. Adsorption behavior of copper onto both raw and $HNO_3$-treated woods was mainly attributed to interaction with carboxylic acid group. For NaOH-treated wood, carboxylate ion produced by hydrolysis or saponification was a major functional group responsible for Cu sorption. NaOH treatment of wood changed the ester and carboxylic acid groups into carboxylate group, whereas $HNO_3$ treatment did not affect the production of functional groups which could bind copper. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto NaOH-treated wood. A batch isotherm test using NaOH-treated wood showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model.

• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.732-750
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• 2019

Air drying was carried out on 15 Korean red pine logs to provide a prediction model of the moisture content (MC) change in the wood during drying. The final MC was 17.4% after 880 days since the beginning of air drying in the summer for 6 Korean red pine logs with 68.7% initial MC. The final MC was 16.0% after 760 days since the beginning of air drying in the winter for 9 Korean red pine logs with 35.8% initial MC. A regression model with R-squared of 0.925 was obtained as a result of multiple regression analyses with initial MC, top diameter, temperature, relative humidity, and wind speed as independent variable and and MC change during air drying as dependent variable. The initial MC and top diameter, which is the characteristic of Korean red pine, have greater effect on the MC decrease during air drying compared to meteorological factors such as the temperature, relative humidity, and wind speed. Two-dimensional mass transfer analysis was performed to predict the MC distribution of Korean red pine logs during air drying. Two prediction models with different air drying days and different meteorological factors for the determination of the diffusion coefficient and surface emission coefficient were presented. The error between the different two methods ranged from 0.1 to 0.8% and the difference from the measured value ranged from 2.2 to 3.6%. By measuring the internal MC during air drying of Korean pine logs with various initial MC and diameter, and calculating the moisture transfer coefficient in wood for each meteorological condition, the error of the prediction model can be reduced.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.128-133
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• 2002

This study was conducted to investigate the influence of storage time on the sapstain development of Japanese red pine and Korean pine logs during storage in log yard, and their stain characteristics. Japanese red pine and Korean pine trees were harvested and cut into logs in mid January of 2001. These logs were transported to the two local sawmills where they were closely stacked in remote parts of log yard. The logs were then sampled destructively by cutting seven to nine 3-cm long discs along the length of each log at intervals of 3, 4, 5, 6, and 8 month after felling. The stain coverage and maximal radial penetration of stain were measured from the discs of the sampled logs after the isolation of causal staining fungi. The sapstain was primarily infested by the attack of bark beetles and the species of bark beetle was identified as Tomicus piniperda. The main fungal species isolated from stained wood was Ophiostoma species. Based on the present study, the logs could be stored in log yard until May without stain; but stain development was rapid after May and the severity of stain increased proportionally with storage time. Korean pine was more susceptible to fungal stain than Japanese red pine. During summer storage, decay started to develop in logs and the main species were identified as Tyromyces sp. and Schizophyllum commune. Information provided in this paper would be very useful to develop more effective control strategies for sapstain prevention in Japanese red pine and Korean pine logs.

• Journal of the Korea Furniture Society
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• v.20 no.1
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• pp.95-104
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• 2009

The study was carried out to analyze wood quality of coffin board, the wood species of coffin excavated in Youngdong, Korea. All coffin woods were identified as hard pines, Korean red pine(Pinus densiflora S. & Z.). According to wood quality of coffins, inner coffins of Bae Cheon-Jo and his wife showed similarity and dissimilarity comparing with several literatures. The similarity was in the structure of panels, bottom lining board and charcoal layer, and the dissimilarity was in jointing. From the analysis of fibrous materials attached to coffin woods, the paper mulberry and cotton fibers were identified. In the inner coffin of Bae Cheon-Jo, tool traces by handle planer were observed.