• Journal of the Korean Wood Science and Technology
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• 제26권2호
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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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• 제29권2호
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• pp.76-83
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• 2001

춘재부와 추재부로 분리한 일본삼나무재 시험편을 이용하여 목재의 목리방향에 평행하는 압축응력에 대한 목재의 역학적 거동을 관찰하였다. 그 결과, 춘재와 추재간에는 역학적 거동의 차이가 있었는데, 춘재는 하나의 연륜내에서 거의 동일한 세포벽율을 나타내며 응력의 증가에 대하여 변형이 직선적으로 증가하였다. 그러나 한 연륜내에서 수에서 수피방향으로 세포벽율이 점차 증가하는 추재부에서는 응력의 증가에 따라 변형량이 더 커져서 곡선적으로 증가하는 경향을 나타내었다. 또한 하중속도가 변화할 때 종적탄성율의 하중속도 의존성은 춘재부와 추재부에서 비슷하게 나타났다. 추재부의 종압축강도와 종압축탄성율은 춘재부의 약 4백의 수치를 나타내었다.

• 한국가구학회지
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• 제17권4호
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• pp.49-57
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• 2006

Larix kaemferi is now a major economic kind of trees and is produced in large quantity every year. Thus, the study of Larix kaemferiis conducted to acquire the basic date of measures for the reasonable use, clarifying the relation with the compression strength parallel to grain according to anatomical properties by heartwood and sapwood, and earlywood and latewood. As the length of an earlywood tracheid and the radial wall thickness of earlywood and latewood tracheids increased, the compression strength rose, and as the height of uniseriate ray in cell number increased, the compression strength parallel to grain fell. The major anatomical factors effecting on the compression strength parallel to grain of heart wood were the radial wall thickness of a latewood tracheid and the length of a latewood tracheid, while in sapwood, the length of an earlywood tracheid and the radial wall thickness of earlywood and latewood tracheids were the major factor on it.

• 한국가구학회지
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• 제19권2호
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• pp.111-115
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• 2008

An experiment was conducted to know ultra-pure distilled water penetration depth through large vessel, small vessel, latewood fiber and earlywood fiber in longitudinal direction of Castanea crenata. In heartwood, latewood fiber transported water more than large and small vessel. While in sapwood, small vessel conduction depth was found the highest. Penetration depth of water after 15.0 seconds, no significant difference was observed among earlywood fiber, latewood fiber and earlywood vessel. Whilst in heartwood, no statistical difference was observed among earlywood fiber, latewood fiber and earlywood vessel. At the beginning, the speed of water penetration was high and then gradually decreased.

• Journal of the Korean Wood Science and Technology
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• 제20권2호
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• pp.51-60
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• 1992

This study was performed to investigate the effect of green sorting before drying on the high-temperature drying characteristics of southern yellow pine dimension lumber(2"${\times}$6"${\times}$12'). To test the advantages of weight sorting, green lumber was seperated into heavy(above 55 1b), medium(50-55 1b), and light(below 50 1b)weight classes. Pieces in each weight class were subgrouped into high(above 35%) and low(below 30%) latewood groups. Groups were dried and seperated by a standard commercial high-temperature schedule; dry bulb temperature $245^{\circ}$ F, wet bulb temperature $180^{\circ}$ F, and air velocity 1200fpm. The results obtained were as follows; 1. There was a highly significant correlation between annual rings per inch(X) and percent-latewood(Y). The regression equation was Y=24, 5047+1.3272X. 2. There were highly significant correlations between either annual rings per inch($X_1$) or percent-latewood($X_2$) a.d specific gravity in green wood(Y). Their regression equations were Y=0.4260+0.0081$X_1$ and Y=0.3749+0.0029$X_2$, respectively. 3. Heavier weight charges dried more slowly than lighter weight charges. 4. Board-to-board variation in green or dry moisture content was less for all seperate weight classes than for unseperated control charges. 5. Lower latewood pieces had higher initial moisture content than higher latewood pieces, and then drying time for lower late wood pieces was longer than higher latewood pieces.

• Journal of the Korean Wood Science and Technology
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• 제31권1호
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• pp.61-70
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• 2003

원심법을 이용하여 침엽수 생재 심재부의 조재와 만재에 대한 수분이동경로의 크기를 평가하였다. 또한, 원심처리 후의 포수율 분포와 수분포텐셜의 관계로부터 액체투과성을 측정하였다. 삼나무의 경우, 조재는 0.70 ㎛, 만재는 0.50 ㎛의 반경에서 뚜렷한 피크가 관찰되었다. 솔송나무는 조재와 만재 모두 0.50 ㎛의 반경에서 피크를 나타냈다. 일본전나무와 일본잎갈나무는 조재 0.70 ㎛, 만재 0.30 ㎛의 반경범위에서 피크 값이 관찰되었다. 반면에, 미송과 시트카스푸르수는 뚜렷한 피크 값을 보이지 않았다. 액체투과성은 미송을 제외한 모든 수종에서 조재가 만재보다 좋게 평가되었다.

• Journal of the Korean Wood Science and Technology
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• 제33권6호통권134호
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• pp.1-7
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• 2005

춘천지역에서 생장하는 주요 침엽수 2수종(소나무, 잣나무)과 활엽수 2수종(신갈나무, 아까시나무)의 생장특성을 규명하기 위하여 연륜형성 과정에서 수지구, 타일로시스 및 만재부 형성시기를 조사하였다. 소나무와 잣나무의 수직수지구는 각각 7월 초 중순경과 5월 초순경에 형성되어 잣나무 수직수지구의 출현이 소나무보다 상당히 빠른 것을 보여주었다. 신갈나무의 도관내 타일로시스는 5월 중순경에, 아까시나무는 5월 하순경에 형성되는 것으로 관찰되었다. 소나무의 만재부 형성기는 8월 중순경, 잣나무는 9월 하순에서 10월 초순경으로 관찰되었다. 신갈나무는 5월 하순경에, 아까시나무는 6월 초 중순경에 조재부 도관의 형성이 완료됨과 동시에 만재부의 도관과 다른 세포들이 형성되기 시작하였다. 따라서 동일 환경조건에서 생장하였더라도 수종에 따라 수지구, 타일로시스 및 만재부 형성 시기는 다르게 나타나는 것이 확되었다.

• Journal of the Korean Wood Science and Technology
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• 제21권2호
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• pp.73-80
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• 1993

Pinus koraiensis is one of the most important reforestation species which had widely been planted around the country. Therefore, there are great research needs on the fundamental properties of wood to extend the frequency of uses and adequate availabilities. Research results on the characteristics of anatomical wood properties and changes are summarized as follows: 1. At a horizontal direction of tree trunk, the tracheid length at outer wood gradually becomes shorter as it reaches to pith. The tracheid length having between 32 and 42 annual rings showed over 2.5 times longer than that of pith, and also its length increases from the bottom to the top of the stem. 2. The tracheid diameters in latewood showed a little fluctuations, and the shortest near to the pith in earlywood. The tracheid diameters in earlywood are more than 2 times those of latewood, and the differences between the mature and juvenile wood in earlywood are less than 10${\mu}m$. 3. The tracheid wall thickness in early wood showed a little fluctuations. On the contrary, tracheid wall thickness in latewood rapidly increases from the pith to the bark. The tracheid wall of mature wood showed 10 to 20% thicker than that of juvenile wood. 4. The fibril angle at the secondary walls of tracheid within an annual ring showed higher degree in earlywood than that of latewood. The highest tracheid fibril angle was observed at around the pith of both earlywood and latewood. Then, fibril angle slowly decreased toward outer wood, and was stabilized after 15 years. 5. Structural boundaries between mature and juvenile wood from Pinus koraiensis are divided by 13 to 19 annual ring and distance of 5 to 8cm from the pith.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.34-36
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• 2003

In boreal conifers in China's Northeast area, maximum latewood density (MXD) of tree-ring varies in response to growing season temperature. Forest net productivity can be estimated using the Normalized-difference Vegetation Index (NDVI) calculated from satellite sensor data. MXD from the Mohe site in this area was compared with estimates of NPP for 1982-1999 produced by the NDVI model, which was established based on the relationship of leaf area index (LAI) and NDVI. The result shows that the MXD series correlated significantly with the NDVI model estimates series, suggesting that MXD appeared to be an appropriate index for productivity or canopy growth in region where forest productivity is strongly temperature-related.

• 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.