• Journal of the Korean Wood Science and Technology
• /
• v.16 no.3
• /
• pp.65-71
• /
• 1988

캐나다가 미국산 활엽수재의 가장 큰 수입국이며 수입된 일부 제재목과 수입원목으로 제조된 단판중 일부는 유럽으로 재 수출되고 있다. 수입 물량적인면에서 캐나다는 다른 국가와의 격차는 좁혀지더라도 미국산 활엽수재의 제1위 수입국의 위치를 당분간 유지할 것이다. 유럽에서의 제재목 수요가 1973년부터 1983년간의 10년간에는 급진적으로 증가 되었지만 1984년에 는 갑자기 감소되었다. 이와같은 현상은 과거 유럽 전통가구에 소재(素材)를 많이 사용했지만 현재는 소재(素材)를 적게 사용하고 단판이나 인쇄한 종이를 붙인 파아티클 보오드(PB)를 더욱 많이 사용하고 있기 때문이다. 현재 유럽지역에서는 가구의 크기를 줄이거나 가구에 사용되는 원자재의 비용을 줄임으로 제품의 가격을 싸게하여 소비자에게 보다 경쟁력있는 가격으로 제품을 공급할려고 하고 있으며 활엽수재의 가격이 너무 비싸 가구제조업체들은 소재(素材)를 다른 것으로 대체하고 보다 값싼 수종을 모든 지역에서 찾고 있는 중이다. 태평양 연안국가에서의 미국산 활엽수재의 수입 물량은 계속 증가되어 미국산 활엽수 총 수출 물량의 약 23% 정도 된다. 자유중국과 일본에서 미국산 활엽수재를 가장 많이 수입하고 있다. 자유중국은 주로 수출용 가구부품및 가구에 사용되는 red oak와 white oak 가 주 수종이고 가구는 미국으로 재 수출하고 있다. 일본은 주로 black cherry, yellow poplar와 cotton wood를 수입하는데 수입량의 약 67%는 대패질한 건조 가공품이다. 자유중국에서와는 달리 일본에서의 미국산 활엽수의 용도는 일본산 활엽수의 대체수종으로 허용되고 있다. 앞으로 일본에서의 미국산 활엽수재의 수요는 일본 국내시장의 요인에 의해 좌우될 것인데 한정된 물량의 일본산 활엽수재와 온대 활엽수재의 요구에 영향을 받을 것이다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.45 no.1
• /
• pp.6-12
• /
• 2013

TFormic acid-hydrogen peroxide (or performic acid) pulping process needs milder reaction condition than other chemical pulping process. Two-step formic acid-hydrogen peroxide pulping process can produce the chemical pulp with similar pulp yield and lignin content compared with soda-anthraquinone process. Formic acid-hydrogen peroxide pulp can be produced less xylan content than other alkaline pulps, which favor for dissolving pulp production. Formic acid-hydrogen peroxide pulp showed better response beating than soda-anthraquinone(AQ) pulps with reaching target freeness with less beating. Also, formic acid-hydrogen peroxide pulp had better tensile index at similar freeness level compared with soda-AQ pulps.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.5
• /
• pp.85-90
• /
• 2015

To use the African tulip tree (Spathodea campanulata) as raw material for chemical pulping, soda and soda-AQ pulping was investigated. In chemical compositional analysis, lignin contents of African tulip (33.1%) was higher than other hardwood such as Yellow poplar (17.5%), Acacia (27.1%), or Eucalyptus (24.2%). Soda or soda-AQ pulping with African tulip tree resulted in yield at 43.4-44.8% with 29.5-34.5 Kappa number, pulping condition with 20-22% active alkali. Kappa number of African tulip tree pulp was quite higher than other tropical hardwood (Eucalyptus or Accacia) with less yield due to higher lignin content in wood. Fiber length and width of pulp from African tulip tree was similar to Accacia pulp and shorter than eucalyptus pulp.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.4
• /
• pp.436-442
• /
• 2011

In this study, the Total Volatile Organic Compounds (TVOC) emitted from wood-based panels were compared by two analytical methods using the GC/FID and the GC/MS. Japanese Larch, Yellow Poplar, Particle Board (PB) and Medium Density Fiberboard (MDF) were selected as target materials. Major compounds emitted from the panels were Toluene, ${\alpha}$-pinene, ${\beta}$-pinene and limonene. In case of TVOC using GC/FID method, MDF E2 (1,497 ${\mu}g/m^3$) revealed the highest concentration among all wood-based panels, while Japanese Larch (1,772 ${\mu}g/m^3$) showed the highest value with respect to GC/MS method. Furthermore, it was found that the amount of VOC emitted from panels was different depending upon analytical methods. This significant difference was attributed to analytical sensitivities of GC/FID and GC/MS for various VOC. Besides, it was found that the composition ratios of main VOC compounds were not significantly different.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.5
• /
• pp.456-465
• /
• 2013

Log cross sections of yellow poplar were dried in a radio frequency vacuum (RFV) dryer under alternating vacuum and release (AVR) process. The average moisture content (MC), temperature and vapor pressure at the volumetric center were monitored as functions of time. Three different log thicknesses (33, 60 and 75mm) were tested. The results show that the AVR process caused an increase in the drying rate when the moisture content was above fiber saturation point (FSP, about 30% MC) but that it had an inverse effect on the drying rate when the MC was below FSP. The effect of the AVR process on the drying rate decreased, and the severity of heart checks increased, with the increase in the thickness of the specimens.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.5
• /
• pp.511-526
• /
• 2018

Effects of heat treatment on the characteristics of Royal paulownia (Paulownia tometosa) wood were investigated. The results were compared with those of Suwon silver poplar (Populus tementiglandulosa) and Korean red pine (Pinus densiflora) woods. The wood samples of the three species were treated at $160^{\circ}C$, $180^{\circ}C$, $200^{\circ}C$ and $220^{\circ}C$ in an electric furnace for 2 hours. The changes of color, density, mass loss, and relative crystallinity were investigated before and after heat treatment. The lightness ($L^*$) decreased rapidly from $200^{\circ}C$ in all species. There were no change in red-green chromaticity($a^*$) and yellow-blue chromaticity($b^*$) of Royal paulownia and poplar woods with increasing temperature. Whereas, yellow-blue chromaticity($b^*$) of Korean red pine wood decreased sharply from $200^{\circ}C$. Royal paulownia wood showed appreciable color change(${\Delta}E^*$) after heat treatment above $180^{\circ}C$. Poplar and pine woods, however, presented significant color change from $160^{\circ}C$. Color change of the three wood species increased rapidly with increasing temperature. Mass loss of the three wood species by heat treatment was the highest in the Royal paulownia wood and the lowest in the pine wood. Mass loss and relative crystallinity increased and density decreased slightly with increasing temperature. Consequently, it is revealed that Royal paulownia wood showed considerable differences in the temperature of color change, weight loss and change of relative crystallinity compared to the other wood species.

• Journal of Korean Society of Forest Science
• /
• v.105 no.4
• /
• pp.463-471
• /
• 2016

The purpose of this study was to develop allometric equations for identifying the amount of wood and building biomass statistics of L. tulipifera by density, biomass expansion factors and root ratio. For this purpose, total of 40 trees were sampled, which were used consideration the area and the DBH class. As a results, the wood density was $0.43g{\cdot}cm^{-3}$, biomass expansion factors were 1.2, root ratio was 0.2 and uncertainty were 3.9%, 4.6%, 24.1%, respectively. Allometric equations for above ground of L. tulipifera trees were $W=0.060D^{2.524}$. Total and underground allometric equations were $W=0.063D^{2.578}$, $W=0.010D^{2.591}$, respectively.

• Journal of Plant Biotechnology
• /
• v.43 no.1
• /
• pp.110-118
• /
• 2016

We compared germination efficiency for somatic embryos (SE) of Liriodendron tulipifera using semi-solid (SS), temporary immersion bioreactors (TIB), and continuous immersion bioreactors (CIB) to produce vigorous plants. The bioreactors were designed to be immersed in liquid media with plantlets with an adjustable immersion time. TIB and CIB improved germination rates up to 80.86% and 95.21%, respectively, however, CIB produced more hyperhydric plantlets than TIB. The height of plantlets in TIB was significantly higher than for those in CIB. Fresh weights of plantlets grown in CIB of were significantly lower than for those grown in TIB. The lowest chlorophyll concentration was found in in vitro plantlets from CIB. We examined abnormally developed leaves, stems, and apical zones of in vitro plantlets that were produced in CIB. Among the three types, SS showed the highest stomatal density and the shortest stomatal length in in vitro plantlets. After acclimatization, plants from CIB exhibited the lowest values in biomass, such as height, root collar diameter, leaf fresh weight, leaf length, leaf width, petiole length, petiole diameter, and leaf area. Photosynthesis and transpiration rates of ex vitro plants were not significantly different among the three culture types, but stomatal conductance was higher in TIB than in the SS and CIB. Therefore, the results suggest that TIB is the preferable bioreactor to improve in vitro plantlet regeneration of L. tulipifera. TIB-originated plants showed higher growth rate than SS and CIB after transferring to soil.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.1
• /
• pp.67-72
• /
• 2018

This study was conducted to investigate a potential of Yellow poplar (Liriodendron tulipifera L.) as a raw material for the manufacturing of particleboard (PB) and oriented strandboard (OSB). PB panels were prepared at the parameters of $0.7g/cm^3$ density, 15 mm thickness, three-layer, $E_1$ grade urea-formaldehyde (UF) resin, emulsion wax, and hardener. OSB panels were manufactured with a density of $0.65g/cm^3$, thickness of 10 mm, and $E_1$ grade of UF resin. Particle size of the face layer of PB was 20~80 mesh with 7~9% moisture content (MC), while that of core-layer was 3~20 mesh with 3~5% MC, which was similar to the production condition of commercial PB. As a result, the manufactured PB panels with 15.8 mm thickness, $0.7g/cm^3$ density, and 5.8% MC satisfied the requirement of bending strength of 15 type PB of Korean Industrial Standard (KS F 3104). Both internal bonding (IB) strength and surface screw withdrawal resistance also satisfied the requirement of 18 type PB of the standard. But, the edge screw withdrawal resistance satisfied the requirement of 15 type PB of the standard. These differences in properties could be due to the slenderness ratio of raw particles. In case of OSB panels with 10.7 mm thickness, $0.68g/cm^3$ density, and 5.8% MC satisfied all the requirements of bending strength, screw withdrawal resistance, and IB strength of 18 type PB of the standard. These results suggest that Yellow poplar wood has a good potential as a raw material for the production of PB and OSB.

• Journal of Korean Society of Forest Science
• /
• v.101 no.4
• /
• pp.613-618
• /
• 2012

The 5-year-old seedlings and emblings which regenerated from somatic embryos were compared to the height, DBH, foliar characteristics, content of chlorophyll (chlorophyll a, b and total chlorophyll), carotenoid and leaf microstructure in Liriodendron tulipifera. In comparison of height and DBH (diameter at breast height), no significant differences were found in height (seedling, 3.8 m; embling, 3.87 m) and DBH (seedling, 12.09 cm; embling, 12.53 cm). The emblings and seedlings were similar in values of length (seedling, 108.11 mm, embling, 113.59 mm), width (seedling, 149.1 mm; embling, 167.71 mm), surface area (seedling, $119.92mm^2$; embling, $164.43mm^2$), fresh weight (seedling, 2.1 g; embling, 2.62 g) of leaf, and length (seedling, 81.49 mm; embling, 98.41 mm) and thickness (seedling, 1.66 mm; embling, 1.98 mm) of petiole. In case of chlorophyll content in the leaves, the chlorophyll a (seedlings, $11.2{\mu}g/g$; emblings, $13.2{\mu}g/g$), b (seedlings, $4.8{\mu}g/g$; emblings, $5.4{\mu}g/g$) and total content were higher in emblings ($930.2{\mu}g/g$) than seedlings ($800.1{\mu}g/g$), however, content of carotenoid (seedlings, $260.3{\mu}g/g$; embling, $265.2{\mu}g/g$) showed similar in both plants. Leaves of emblings had a similar pattern of histological structure (palisade or sponge parenchyma) to that of seedlings leaves. Therefore, the results showed that there were no remarkable growth differences when compared with 5-year-emblings and seedlings of yellow poplar.