• Journal of agriculture & life science
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• v.45 no.1
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• pp.9-14
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• 2011

Larix kaempferi is a tree with a major economic impact and is processed in large quantity every year in Korea. This study was carried out to collect basic data for the reasonable use of Larix kaempferi and to investigate the relation between anatomical properties and modulus of rupture (MOR) for heartwood and sapwood. As the length of earlywood tracheid and the radial wall thickness of earlywood tracheid and latewood tracheid increased, the modulus of rupture (MOR) increased, but decreased with increasing microfibril angle. Statistical analysis by the stepwise regression technique shows that the main factors affecting the modulus of rupture (MOR) of heartwood are the microfibril angle and the radial wall thickness of latewood tracheid, while those affecting MOR of sapwood are the length of earlywood tracheid and the microfibril angle.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.41-50
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• 2002

Small clear specimens of Quercus acutissima Carr. and Larix caempferi Carr. were used to measure shrinkage and thermal conductivity for the reasonable and effective use. All samples were conditioned to 18, 12, 5% moisture contents in a humidity chamber of 86, 66, 20% relative humidity(RH), respectively and room temperature(23℃) All specimens were conducted on the shrinkage and thermal conductivity test at each MCs. These processes(cycle) were repeated three times. The radial and tangential shrinkages of Quercus acutissima Carr. and Larix caempferi Carr. decreased at each level of MCs, with the increasing cycles. The radial and tangential shrinkages increased as the specific gravity(on oven-dry weight and volume basis) increased. Thermal conductivities of the radial and tangential direction of Quercus acutissima Carr. and Larix caempferi Carr. increased at each levels of MCs, with increasing cycles. Good correlations were obtained between shrinkages and thermal conductivities of radial and tangential direction, and specific gravity (on oven-dry weight and oven-dry volume basis) and MC.

• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.24-33
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• 2005

Fallen needles (8.5kg) of Larix kaempferi were separately collected, extracted with 95% EtOH. EtOH extract was evaporated under reduced pressure, concentrated then successively fractionated with a series of hexane, methylene chloride, ethylacetate and water on a separatory funnel. Then, each fraction was freeze dried. A portion of ethylacetate and water soluble powder were packed on a column chromatography (Sephadex LH-20) eluting with aqueous MeOH and EtOH-hexane mixture. Spectrometric analyses such as NMR and FAB-MS including TLC were performed to characterize the structures of isolated compounds. 5 compounds were isolated from the fallen needles of Larix kaempferi. The antioxidative activities of each fraction and isolated compounds were done by DPPH radical scavenging test.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.44-48
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• 2003

Flexural properties were investigated on clear specimens made from small diameter thinned trees of pitch pine (Pinus rigida Mill.), Japanese red pine (Pinus densiflora Sieb. et Zucc), Japanese larch (Larix kaempferi Carr.), and sawtooth oak (Quercus acutissima Carr.). MOR and MOE values of small clear specimen were depended on the species. The highest density of sawtooth oak shows the highest values of MOR and MOE. However, the lowest density of Japanese larch shows the lowest values of MOR. It was also shown that flexural properties could be predicted by stress wave MOE, since the correlations between stress wave MOE and flexural properties were relatively good.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.87-91
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• 2007

The needles of L. kaempferi was extracted with 95% ethanol and successively partitioned with n-hexane, $CH_2Cl_2$ and EtOAc. Repeated column chromatography on the EtOAc and $H_2O$ soluble fractions gave three flavan-3-ols, one flavone glycoside, six flavonol glycosides and one lignan derivative. Their structures were elucidated on the basis of chemical and spectroscopic evidences. The antioxidant activities of the isolated compounds were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. Flavan compounds indicated good antioxidative potentials compared with BHT (butylated hydroxytoluene) and ${\alpha}$-tocopherol as controls. In the anti-inflammatory test on most of the isolated compounds, NO (nitric oxide) assay against the RAW 264.7 (Mouse Macrophage) showed similar inhibitory potentials to NO production of the control. The cytotoxicity was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and most of the isolated compounds indicated no toxicity in various concentration.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.72-80
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• 2006

Fallen needle (8.5 kg) of Larix kaempferi were collected and extracted with 95% EtOH. The EtOH extracts were evaporated under reduced pressure, concentrated, and successively fractionated with a series of hexane, methylene chloride, ethylacetate and water on a separatory funnel to be freeze dried. A portion of ethylacetate and water soluble powder were chromatographed on a Sephadex LH-20 column eluting with aqueous MeOH and EtOH-hexane mixture. Spectrometric analyses such as NMR and FAB-MS, including TLC, were performed on the seven isolated compounds and were elucidated as (+)-catechin, (-)-epicatechin, 2"-O-rhamnosylvitexin, juglanin, afzelin, laricitrin-3-O-${\beta}$-D-glucopyranoside, isoquercitrin and cedrusin.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.60-68
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• 2003

In forest products industry, a variety of nondestructive evaluation techniques are now being used to assess the mechanical properties of structural lumber. Ultrasonic and longitudinal vibration technique are frequently used to assess the modulus of elasticity(MOE) of lumber. The objective of this research was to evaluate the MOE and modulus of rupture(MOR) of small-diameter of Larix log(Larix kaempferi Carr.), using these techniques. In this study, 50 small-diameter logs were nondestructiveively evaluated. The dynamic modulus of elasticity(Eu) of the logs was first evaluated, using an ultrasonic method. After ultrasonic tests, the logs were measured using a longitudinal vibration technique(Ev). Static bending test was then performed on the logs to obtain the static modulus of elasticity(Es) and modulus of rupture of these logs. In general, the dynamic MOE (Ev) of logs was closely co..elated with the stati, MOE for log. Based on the results of these experiments, it can be concluded that small-diameter Larix logs can be successfully evaluated by Ultrasonic and longitudinal vibration technique. The experimental results indicated that the ultrasonic technique is effective to the log, which contains many knots. The longitudinal vibration technique is effective to the log, in which many cracks are included.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.9-16
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• 2008

Ribbed birch (Betula costata Trautv.), Japanese larch (Larix kaempferi (Lamb.) Carr.), and tulip tree (Liriodendron tulipifera L.), were used as experimental specimens to measure the sound absorption coefficient with various resonator types, regular resonator (Type-R), eccentric resonator (Type-E), aligned resonator (Type-A), and screwed resonator (Type-S). Resonators consisted of the simple perforation by hand drilling. Sound absorption performances of the resonators installed perforations were better than those of untreated specimens. They were varied with the resonator's type and wood species. Increased area by a wood screw gave no significant change on the sound absorption.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.298-305
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• 2010

The effects of wood species, chemical components, filler loading level, filler particle size, and coupling agent on the water absorption property of the wood flour filled polypropylene (PP) composites were investigated in this study. After 500, 1,000, 1,500, 2,000, 2,500 and 3,000 hr water immersion, Quercus (Quercus accutisima Carr.) and Maackia (Maackia amuresis Rupr. et Maxim) showed significantly lower water absorption properties compared to Larix (Larix kaempferi Lamb.). As wood flour loading increases from 10 to 50 wt%, most wood species showed increased water absorption after a given immersion period. Particle size of wood flour proved to have very significant effects on water absorption of the composites. The effect of coupling agent was positive in terms of lowering water absorption of the composites. As the treatment level of coupling agent increases, the water absorption of the composites decreases. The lowest water absorption was obtained at the lower wood flour loading (Maackia), smaller particle size and by the addition of coupling agent. Thickness swelling of the composites shows close dependency on water absorption.

• Journal of the Korea Furniture Society
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• v.17 no.3
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• pp.17-21
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• 2006

An investigation was done to know the warty layer structural difference in bordered pit of longitudinal tracheid in Pinus densiflora Sieb. et Zucc., Pinus koraiensis Sieb. et Zucc., Pinus rigida Mill. and Larix kaempferi Carr. grown in Korea. Among the four wood species, warty layer was found in bordered pit of longitudinal tracheid of Pinus densiflora Sieb. et Zucc. and Pinus rigida Mill. The mean height and horizontal diameter of warty layer was found highest in Pinus densiflora Sieb. et Zucc. The height of warty layer was found the highest in juvenile wood of Pinus densiflora Sieb. et Zucc. and it gradually decreased towards the matured wood.