• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.26-33
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• 1990

To study the wood quality factors of Populus nigra $\times$ maxmowiczii known a rapidly growing species, the variations of green moisture contents, bulk density, wood fibre dimensions, microfibril angles, and number of leaf knot in stem wood were investigated. The heartwood contained a higher moisture content than the corresponding sapwood. Bulk density in radial patterns variations decrease outward from the pith, then increase toward the bark. The wood-fiber length and diameters had somewhat smaller values than on Populus alba $\times$ glandulosa or Populus euramericana. The microfibril angles decreased rapidly toward the outside, and their mean values were about 16 degree. The grain angles run nearly parallel to the cell axies. Number of leaf knot showed a fluctural change above ground level to a point near the base of the crown and then increased rapidly to the top of tree and average number of leaf knot varied exclusively from tree to tree.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.42-49
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• 1988

Anatomical characteristics on abnormal type of bisected compression woods and light colored wood intervened between these dark colored compression woods on under part and their respective opposite woods on upper parts of cross section in Pinus densiflora S. et Z. stem were compared through optical microscopic investigation. and the obtained results were summarized as follows: 1. Tracheid length increased linearly as the number of rings from the pith increases in all investigated parts, but increasing tendency in tracheid length was similar within bisected two compression woods and their opposite woods. 2. Tracheids were the shortest in bisected two compression woods and tracheid length in intervened wood between these two compression woods was longer than in compression woods but shorter than in the opposite woods. 3. Bisected two compression woods and intervened wood between these two compression woods revealed similar features in tracheid transition from springwood to summerwood, intercellular space, tracheid entanglement, and cross sectional view of tracheid. but spiral check was observed only in these two compression woods, therefore the intervened wood between these two compression woods disclosed anatomical characteristics similar to, not typical of, compression woods.

• 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 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.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.252.2-252.2
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• 2010

Biomass is considered to be a major potential fuel and renewable resource for the future. In fact, there is high potential to produce the large amount of energy from biomass around the world. In this study, to obtain basic data for practical application of wood pellet and wood pellet boiler system as heating system in agriculture, agricultural biomass resources were surveyed, pellet was made of agricultural by-product such as stem of rape, oat and rice, ricehusk and sawdust and wood pellet boiler system with capacity of 116 kW was manufactured and installed in greenhouse of $38.5m{\times}32m$. High heating value, bulk density and ash content of pellet made of agricultural by-product and efficiency and heating performance of this system was estimated. Rice straw was the largest agricultural biomass in 2005 and the total amount of rice straw converted into energy of $131.71{\times}10^{11}$ kJ. And in 2005, total amount of forest' by-product converted into energy of $29,277.05{\times}10^{11}$ kJ. High heating values of pellets made of agricultural by-products of stem and seed of rape, stem of oat, rice straw and rice husk were 16,034, 16,026, 16,089, 15,650, 15,044 kJ/kg respectively. High heating values of pellets made of agricultural by-products were 83.6% compared to that of wood pellet. Average bulk density of pellets made of agricultural by-products of stem and seed of rape, stem of oat, rice straw and rice husk was 1,400 $kg/m^3$. Ash contents of the pellets were 6.6, 7.0, 6.2, 5.5, 33% respectively. Ash content of rice husk pellet was the largest compared to other kind of pellets. To increase efficiency of agricultural pellet boiler, the boiler adopted secondary heat exchanger. The agricultural pellet boiler designed and manufactured in this study had high efficiency of 84.2% compared to the conventional agricultural pellet boiler, when water flow rate, exhaust gas temperature and average combustion furnace temperature were 39L/min, $180^{\circ}C$, $680^{\circ}C$ respectively. And pellet supplying and pausing time were 13, 43 seconds respectively. In March of 2010, prices of wood pellet, agricultural tax free diesel, diesel, kerosene were 350 won/kg, 811 won/L, 1,422 won/L, 976 Won/L respectively. Also in terms of energy, prices per same heating value were 77.8, 90.1, 158, 108.4 Won/Mcal. Energy saving rate of wood pellet was 16, 50, 39% compared to agricultural tax free diesel, diesel and kerosene respectively.

• Journal of the Korean Wood Science and Technology
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• v.46 no.2
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• pp.125-131
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• 2018

This study was conducted to understand and to compare the qualitative aspects of anatomical characteristics in compression wood (CW), lateral wood (LW), and opposite wood (OW) in a stem of Ginkgo biloba. The qualitative analysis was examined by optical microscopy and scanning electron microscopy. CW in Ginkgo biloba disks were dark brown in color, and the OW and LW were light brown in color. CW and OW showed abrupt transitions from earlywood to latewood, while LW showed a gradual transition. Cross sections of CW presented circular tracheids with angular outlines, many intercellular spaces, and varying sizes of lumens. Cross sections of LW and OW showed rectangular tracheids, fewer intercellular spaces, and varying sizes of lumens. In radial sections, CW showed an irregular arrangement of tracheids in earlywood, while LW and OW showed comparatively regular arrangements. Slit-like bordered pits on the tracheid cell wall, piceoid pits in the crossfield, and a few spiral checks were present in CW. LW and OW showed bordered pits with slightly oval-shaped apertures, as well as cuppresoid pits in the crossfields. Rays were primarily uniseriate, with few biseriate rays in the tangential sections of CW, LW, and OW. The tips of the tracheids were branched in CW but had a normal appearance in LW and OW.

• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.317-329
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• 1987

A comparative anatomy between the secondary xylem in the root and the stem of some Korean Lauraceae, including 6 genera and 7 species, was carried out in this study. The results are as follows; diameter and length of vessel element and fiber are wider and longer in the root than the stem. The angle of end wall of vessel element is more inclined in the root than the stem. Also more number of bar on the perforation plate of vessel element in root wood is found. From the anatomical characters of root and stem wood in some Lauraceous species, it is suggested that the wood of the root is phylogenetically mote primitive than that of the stem, except the diameter of vessel element.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.1-12
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• 1989

To study the structure of opposite wood in the angiosperms. samples were cut from stems and branchs of 10 spcies growing in Korea. The opposite side was defined as being along a line passing from the most wide annual ring of the tension wood on the upper side to the pith and extrapolated through the opposite side. lateral sides being on the right and left of this line. The stem woods growing almost horizontally were surveyed the structural features of the well-developed opposite wood for the tension wood. In the annual-ring of the well-developed opposite woods. an investigation was made on how the dimension of elements, microfibril angles. and cell wall layers change from tension side to opposite side. The structural characteristics of opposite wood in hardwoods realized in this study are as follows: 1. The vessel diameters increased continuously to ward the opposite side in which the values were maximum. The vessel length also increased toward opposite side. but the rates of increase were smaller than those in the vessel diameters. 2. The wood fiber length were decreased from tension toward opposite side. but the rates of decrement were f1actuated within the sampled species. 3. The microfibril angles had the minimum values on the tension side. then increased steeply toward the opposite side in which the values maximum. 4. In the percentage of elements the vessel elements increased continously at a relative rate from the tension to opposite side, whereas the values of the wood fibers were lower in the opposite than the tension side, but the' variation patterns of rays were not seem distinctly. 5. The component layers of the wood fiber in the opposite woods were very similar to the lateral woods.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.45-52
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• 1993

Surveyed results on the slope of grain and the twist of sawn lumber of Pinus koraiensis, Larix leptolepis, and Pinus densiflora were summarized as follows: 1. The slope of grain of Pinus koraiensis has a Z-grain in the stem axis. The slope of grain was found to be the lowest at near to the pith and then constantly increased. At the height of 0.2m from the base of stem. a cross section of 35 annual rings was found to have a repeatedly increasing and decreasing slope of grain and then constantly decreased. At the height of 1.2m to 7.2m from the base of stem, the slope of grain increased conspicuously until the 10th annual ring, after which it increased near to the bark with repeatedly increasing and decreasing trends. 2. Pinus densiflora has a S-grain in the stem axis. The lowest slope of grain was found at near to the pith, and the highest in the 10 to 35 annual rings from the pith. 3. Larix leptolepis has a S-grain. At the height of 3.2m from the base of stem, the big fluctuation of the slope of grain was found without any particular trend. 4. The slope of grain and the twist between natural and reforested timber of Pinus koraiensis were found to be almost the same trend in viewpoint of the annual ring. The maximum slope of grain of imported Siberian timber of Pinus koraiensis was found at the 10 annual rings, which was quite similar to that of native species in Korea, but the big difference of the twist was found at 140 annual rings. 5. The twist was little at the mature wood of reforested Pinus koraiensis and Siberians and the duplicated part of mature and juvenile woods of those. On the contrary, the twist was great at the duplicated part of mature and juvenile woods of Pinus koraiensis. 6. The twist of Larix leptolepis showed the S-direction which coincided with that of slope of grain. The twist was greatest at the part of juvenile wood and little at the duplicated part of mature and juvenile woods, and little difference of twist was found between mature and juvenile woods. 7. Siberian larix having a minimum slope of grain showed the lowest twist, and the twist at the duplicated part of mature and juvenile woods showed a middle level of both mature and juvenile woods' portions.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.408-415
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• 1991

A tumorous wood formed in a stem of Robinia pseudoacacia L. by steel wire fastening was investigated and compared with normal wood in the anatomy of histological aspect. The tumorous wood appeared to differ from normal wood in irregular orientations of some pores, most wood fibers, and rays deviated from normal direction, somewhat radially elongated pores on cross surface, occasionally distorted wood fiber tips between rays on radial surface, large ray width and height, commonly entangled arrangement of wood fibers on radial surface, frequent occurrence of pore multiples in the latewood, frequent occurrence of gelatinous fibers, and dark gummy substances partially enclosed in the lumina of wood fibers, rays, and axial strand parenchymas.