• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.290-300
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• 2014

In this study, cross-laminated woods were made with spruce wood and the effects of annual ring angles of perpendicular direction laminae on static bending strength performance were investigated. Static bending strength performances of parallel laminated woods with all layers composed of laminae perpendicular to the grain ($P_{\bot}$ type) were in the order of $90^{\circ}$ > $0^{\circ}$ > $45^{\circ}$. The MOE and MOR for the $45^{\circ}$ annual ring angle were 0.0989 GPa and 3.25 MPa, and it showed the lowest values. By placing longitudinal-direction laminae in the core of $P_{\bot}$ type, the strength performances were markedly improved. In the case of cross-laminated woods with perpendicular-direction laminae in the faces ($C_{\bot}$ type), the bending strength performances were in the order of $90^{\circ}$ > $0^{\circ}$ > $45^{\circ}$, but the differences among annual ring angles were less than those of the parallel-laminated woods. In the case of cross-laminated woods with perpendicular-direction laminae in the core ($C_{\parallel}$ type), the bending strength performances were in the order of $45^{\circ}$ > $90^{\circ}$ > $0^{\circ}$ unlike $P_{\bot}$ type and $C_{\bot}$ type. The MOE and MOR for the $45^{\circ}$ annual ring angle were 12.0 GPa and 55.8 MPa, and it showed the highest values.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.3
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• pp.36-45
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• 2010

To analyze the relationship between climatic factors (monthly mean temperature and total precipitation) and tree-ring growths of Quercus mongolica Fischer (Mongolian oak) with different topographic sites in Mt. Worak, more than 10 trees were selected from each of seven stands. Two cores from each tree were measured for ring width. After crossdating, each ring-width series was double standardized by fitting first a negative exponential or straight regression line and secondly a 60-year cubic spline. Seven stands were categorized in two groups using cluster analysis for tree-ring index patterns. Cluster I (four stands) was located in higher elevation (550-812 m) with aspects of east, west and northwest, and cluster II (three stands) was located in rather lower election (330-628 m) with aspects of north and northwest. The aspects of two clusters were not significantly different. Response-function analysis showed a significant positive response to March precipitation for both clusters. It indicates that moisture supply during early spring season is important to radial growth because the cambial growths of ring-porous species, such as Mongolian oak, start before leaf growth. Cluster II showed a positive response to the precipitation of middle and late growing season, too.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.1-8
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• 2005

The initiation and cessation of cambial activities were investigated to find out the growth characteristics of the major species growing in Chuncheon, Korea. The division of cambial zone in Pinus densiflora and Pinus koraiensis began from the middle of March through the end of March. The activity of cambial zone in P. densiflora and P. koraiensis was vigorous from the end of May through the middle of July. During this period the number of cells increased rapidly in radial direction. However, the number of cells in P. densiflora was gradually increased. The division of cambial zone in ring-porous wood, such as Quercus mongolica and Robinia pseudoacacia began in the middle of March, before the formation of vessel. The division of cambial zone in diffuse-porous wood, such as Cornus controversa and Prunus sargentii, began in early April, and then the formation of vessels began after one to three weeks. It was considered that the cambial zone in softwood was ceased from the beginning of November, whereas cambial activities in hardwood ceased in the middle of October. Consequently, the formation of growth ring was different among the species, even though the trees were grown under the same conditions.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.362-366
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• 2010

Carbon isotope ratio ($^{13}C/^{12}C$, expressed as ${\delta}^{13}C$) of tree ring can be proxy of atmospheric $CO_2$ concentration ([$CO_2$]) due to the inter-correlation between atmospheric [$CO_2$], ${\delta}^{13}C$ of atmospheric $CO_2$, and ${\delta}^{13}C$ of plant tissue that assimilates atmospheric $CO_2$. This study was conducted to investigate if ${\delta}^{13}C$ of tree ring of Pinus densiflora in polluted area may show a lower value than that in unpolluted area and to explore the possibility of reconstructing atmospheric [$CO_2$] using its relationship with ${\delta}^{13}C$ of tree ring. During the period between 1999 and 2005, ${\delta}^{13}C$ of tree annual ring tended to decrease over time, and the ${\delta}^{13}C$ in polluted area (-27.2‰ in 2009 to -28.3‰ in 2005) was significantly (P<0.001) lower than that (-26.0‰ in 1999 to -27.1‰ in 2005) in unpolluted area. This reflects a greater emission of $CO_2$ depleted in $^{13}C$ in the polluted area. Atmospheric [$CO_2$] was significantly (P<0.01) correlated with ${\delta}^{13}C$ of tree ring in a linear fashion. Using the linear regression equation, atmospheric [$CO_2$] in the polluted area was estimated to range from 392.3 ppm in 1999 to 410.9 ppm in 2005, and these values were consistently higher than the national atmospheric [$CO_2$] monitored at the Anmyoundo meteorological station (from 370.7 ppm in 1999 to 387.2 ppm in 2005). Our study suggested that it is possible to reconstruct atmospheric [$CO_2$] in a certain area using the relationship between tree ring ${\delta}^{13}C$ and atmospheric [$CO_2$].

• 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 the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.203-213
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• 2011

The age and growth of flathead grey mullet, Mugil cephalus, were studied using samples collected from the coastal water of Yeosu from September 2009 to August 2010. Spawning season estimated from the gonadosometic index (GSI) was from November to January. A method for increasing the readability of the otolith was described and criteria for the interpretation of otolith was provided. The annual ring was formed in September once a year. Annual ring in otolith for flathead grey mullet is validated for fish aged 1-8 using the marginal increment analysis. Using the sectioned otolith, between reader precision was 84%. Also, Within-reader agreement for sectioned otolith age readings was higher (reader 1=84%, reader 2=87%). The relationship between fork length and total weight was TW=$0.022FL^{2.818}$. The estimated von Bertalanffy growth parameters for the flathead grey mullet were $L_{\infty}$=67.97cm K=0.164/year and $t_o$=-0.81year.

• Nuclear Engineering and Technology
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• v.5 no.2
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• pp.150-158
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• 1973

General physical properties and radiation durabilities of some domestic woods and imported lauans were measured and discussed as a preliminary study on the preparation of W. P. C. The data obtained indicate that 1) the hardness of wood is generally proportional to the specific gravity and to the bending strength, 2) the hardness of wood measured in tangential direction to the annual ring increases along with the distance from the center of the annual ring to the peel, 3) the changes of specific gravity under 100 Mrad gamma irradiation are not remarkable, 4) the hardnesses of the soft woods are decreased more -readily than those of the hard woods, but the decreases of hardnesses are not extreme upto 10 Mrad sugges ting that the woods are sufficiently durable to gamma irradiation of below 10 Mard in the preparation of W. P. C.

• Journal of the Korean Wood Science and Technology
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• v.51 no.5
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• pp.345-357
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• 2023

The present study conducted a stem analysis to trace growth information of Japanese larch (Larix kaempferi) and predict the future changes in growth volume. For this purpose, six L. kaempferi trees over 47 years old were cut at 1-2 m intervals from a height of 0.2 m, and circular plates of 5 cm thickness were collected for stem analysis. The analysis indicated that approximately 1-8 years are required to grow up to chest height. The annual height and diameter growth increased rapidly until the trees are 15 years old and gradually decreased after 20 years. The volume of 30-year-old trees in Oegam-ri forests, which were well-managed after artificial reforestation, was 0.4837 m³, whereas that in unmanaged Singi-ri forests was 0.1956 m³. Although the volume of individual trees differed greatly depending on the forest management status, it was found that the volume increased by 1.67-1.76, 2.49, and 3.49 times at 40, 50, and 60 years age, respectively, compared to the legal harvesting age 30. Therefore, factors such as the carbon dioxide reduction effect, forest management benefits, and the condition of trees at the site should be considered before harvesting trees.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.592-599
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• 2015

To investigate the characteristic of age and growth, samples of Megangulus venulosus were collected monthly by dredge in the coastal waters of Gangneung, Korea from January to December 2014. The age of M. venulosus was estimated by measuring the ring radius on the shell. Because the relationship between shell lengths and ring radii in each ring group was regressed well, each ring was considered as an annual growth ring. Based on the monthly variation of the marginal index (MI) of the shell length, it is assumed that the ring of this species was formed once a year during September and November. From the parameters calculated using the average length when the year ring was formed, the estimated von Bertalanffy growth equation were $SL_t=236.3(1-e^{-0.061(t+0.184)})$ in age.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.55-60
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• 2008

This study was carried out to investigate the effect of charcoal meal application on the quality of the wood. As the results, it was observed that annual ring width of seedlings was wider in the plots treated with charcoal meal than the control plots. Depending on the kind of charcoal, annual ring width was widest in the plot treated with Larix kaempferi charcoal, and then was observed in order of Pinus koraiensis > particle board > Quercus acutissima. Latewood percentage and specific gravity were lower in the plots treated with charcoal than the control plots and lowest in Larix kaempferi charcoal plot among the plots treated with charcoal. Tracheid length was longer in the plot treated with powder charcoal than the control plot but tracheid width was not significantly different from the control plot. The cell wall thickness of earlywood was not significantly different between the plot treated with charcoal and the control plot but that of latewood was thicker in the plots treated with charcoal than the control. Microfibril angle was smaller in the plot treated with granulated charcoal than the control plot. However, there was no significant difference between the plot treated with powder charcoal and granulated charcoal.