• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.569-576
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• 2020

This study investigated the characteristics of microfibril angle(MFA) in order to see if there was any difference in pine tree lumber quality among the three mountain areas surrounding the Taebaek Mountains in Korea - Yeongdong (Goseong-gun), Yeongseo (Hongcheon-gun) and Yeongnam (Bonghwa-gun). Pine trees of each mountain area were divided into earlywood and latewood in relation to heartwood part (1959 ~ 1961, 3 annual rings) and sapwood part (2002 ~ 2004, 3annual rings), and measured at tangential section. The microfibril angle showed significant differences between mountain areas. In general, Goseong Mountain was found to have 37.35°, followed by Hongcheon Mountain 32.42° and Bonghwa Mountain 25.75°, in order. The sapwood part had larger angle than heartwood part; and earlywood, than latewood. Variation within a single annual ring tended to be smaller from earlywood toward latewood.

• Journal of Korea Foresty Energy
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• v.18 no.1
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• pp.1-5
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• 1999

Variations in the wood quality were analyzed to utilize Korean pine (Pinus koraiensis S. et Z.) efficiently and to develop suitable use, depending on the stem location. Variations in the tracheid length and width, microfibril angle, compression strength were measured at the heights of 0.3, 1.3, 2.3, and 5.3m in the longitudinal direction of the 20m pine and they were analyzed by Duncan`s multiple range test. Variations in the tracheid length, width and compression strength did not show significant difference, whereas those in the microfibril angle showed significant difference. However, the microfibril angle did not vary with the height of trees, showing inconsistent pattern in change.

• Journal of the Korean Wood Science and Technology
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• v.26 no.2
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• pp.45-50
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• 1998

Tracheid length, microfibril angle, and compression strength were examined in south and north sides of Pinus koraiensis. The sample tree was 57 years old and had been planted in central Korea. Tracheid length on the south side of the tree ranged from 2.87 to 3.40mm and on the north ranged from 3.60 to 3.53mm and mean values were 3.15 mm for the south and 3.26mm for the north. Tracheid length was 0.11 mm longer on the north side than on the south. Microfibril angle on the south side ranged from $12.6^{\circ}$ to $20.3^{\circ}$ and that on the north from $6.8^{\circ}$ to $13.5^{\circ}$; mean values were $16.6^{\circ}$ on the south side and $9.6^{\circ}$ on the north. Microfibril angle was $7.0^{\circ}$ greater on the south side than on the north side. For compression strength on the south and north sides, significant difference at the 95% level was found only at l.3m above the ground level of the sample tree; for compression limit stress, significant difference at this level was found at 1.3 and 5.3m above the ground level. However, compression strength and compression limit stress were greater on the north side than on the south side.

• Journal of the Korean Wood Science and Technology
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• v.33 no.1 s.129
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• pp.21-28
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• 2005

Tracheid length and width, microfibril angle, compressive, bending, and impact strengths between the south and north sides of stem pith in Larix kaemferi were measured. Sample trees were 30 years old which had planted in the central region of Korea. In general, there were no difference in the tracheid length and width, microfibril angle, and strengths between the two sides. And no difference in tangential shrinkage and strengths between the two sides was thought to be due to identical microfibril angle between the two sides.

• 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.36 no.4
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• pp.77-83
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• 2008

Radial and axial variations of microfibril angle (MFA) within stems of three commercial softwoods (Pinus densiflora, Pinus koraiensis and Pinus rigida) grown in Korea were examined by iodine crystal deposition method. The average MFA were $16.4^{\circ}$ in Pinus densiflora, 14.4, in Pinus koraiensis, and $26.2^{\circ}$ in Pinus rigida, respectively. The MFA in earlywood and latewood decreased with age to about 15~20 years, and then remained almost constant. The MFA of latewood was slightly smaller than that of earlywood. The MFA in the three species was a little smaller at the base of stem and decreased slightly with increasing tree height, but no significant difference by height was identified only in earlywood of Pinus rigida. Consequently, it was considered that the MFA could be an useful index for identifying juvenile wood and adult wood of Pinus densiflora, Pinus. koraiensis and Pinus rigida.

• Journal of the Korea Furniture Society
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• v.10 no.2
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• pp.55-61
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• 1999

This research was carried out to investigate the fundamental properties such as the structure of annual ring, density distribution, compressive strength with parallel to grain, relative crystallinity, and microfibril angle of Gumgangsong(Pinus densoflora for. erecta Uyeki). The wood specimens, Gumgangsong and Sonamu(Pinus densiflora S. et Z.), for this experiment were prepared at Ulijingoon Sokwangri and Kyungpook university's forest in Kyungpook province, respectively. Average annual ring width is $2.0mm{\pm}0.3$ in heartwood of Gumgangsong. The respectively of heart wood was over 60 percent in Gumgangsong and 20~50 percent in Sonamu. Heartwood density were ranged from 0.5 to $0.8{\;}g/cm^3$ in Gumgangsong and from 0.4 to $0.5{\;}g/cm^3$ in sonamu. Compressive strength in Gumgangsong and Sonamu was about $30{\pm}5MPa$ and $25{\pm}5MPa$, resepectively. But the relative crystallinity and microfibril angle of two species were not different clearly. From these results of Gumgangsong and Sonamu, therefore, it was considered the main difference factors for both species were annual ring width and heartwood percentage.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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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.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.27-32
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• 1997

This study was carried out to find the relationship between anatomical characters and compression strength parallel to grain of Pinus densiflora S. et. Z., the representative conifer species in Korea. The results were as follows ; 1. The compression strength parallel to grain increased with the increase of tracheid length and wall thickness. The strength, however, decreased with the increase of height of uniseriate ray and microfibril angle. 2. The major factors affecting compression strength parallel to grain in heartwood were radial diameter of latewood tracheid and wall thickness of earlywood tracheid but length and tangential diameter of latewood tracheid were the important factors in sapwood.

• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.323-337
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• 2018

Merkusii pine wood (Pinus merkusii) was extensively planted throughout Indonesia, where it is only indigenous in northern Sumatera, by the Dutch during colonial times. The demand for this wood species, especially in the domestic market, has increased notably, despite its limited durability regarding decay resistance. The purpose of this study was to investigate the occurrence of juvenile and mature wood on merkusii pine and to analyze its radial features from pith to bark based on density, shrinkage, static bending in modulus of rupture and modulus of elasticity, fiber length, microfibril angle, and durability. A segmented modeling approach was used to find the juvenile-mature transition. The graveyard test was performed to characterize the termite resistance from pith to bark of merkusii pine. The maturations were estimated to start at radial increments of 15 cm from the pith by fiber length and of 12 cm from the pith by microfibril angle. The projected figures for the proportion of juvenile wood at breast height were around 65%. The results also indicate that the pine wood was $0.52g/cm^3$ in density, 1.45 in coefficient of anisotropy, which indicates its good stability, 7597 MPa in modulus of elasticity, and 63 MPa in modulus of rupture. Natural durability against subterranean termite of the merkusii pine wood was rated to be grade 4 to 0 from pith to bark. However, after being treated by Entiblu and Enborer preservatives, its rating increased to grade 10 to 9.