• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.17-26
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• 2003

Nalita wood(Trema orientalis) is one of the fastest growing woods in the world. It may be a viable species for pulpwood. The physical, chemical and morphological properties of Nalita were studied. The total lignin, pentosan and holocellulose content in Nalita wood were 24.7%, 22% and 81.2%, respectively. Its fiber length was about 0.92 mm, which are comparable to Acacia mangium. Nitrobenzene oxidation of Nalita wood meal indicated that the guaciayl and syringyl unit were the major constituent of Nalita lignin. Nalita produced 50% pulp yield at Kappa number 21 in soda-anthraquinone process. The strength properties of Nalita pulp were comparable to other tropical hardwood pulp. At $40_{\circ}$ SR, the breaking length, burst index, tear index and total energy absorption were 6000 m, $3.5kPa{\cdot}m^2/g\;and\;7.0mN{\cdot}m^2/g\;and\;75J/m^2$, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.164-169
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• 2000

The reconstituted tobacco leaves(RTL) playa major part in the control of the low density and tar cigarette. Reconstituted tobacco manufactured by the papermaking process has much higher filling power than homogenized tobacco manufactured by slurry and rolling process. Fragile reconstituted tobaccos are liable to lead to small particles detrimental for filling power so they must be properly flexible. This work was conducted to determine the effect of CaCO$_3$ addition in paper-making process on the filling power and the flexibility of the reconstituted tobacco and to obtain the fundamental informations for improving the quality of domestic reconstituted tobacco. We analyzed the wood fiber species, the filler level, the fiber length, the fineness level and observed the surface of the RTL. From the obtained results, we could determine that foreign reconstituted tobacco was manufactured by blending softwood with hardwood and over 8% of calcium carbonate at the addition level. The domestic RTL has much higher fine fiber level by 23.2 % than that of foreign, so the refining treatment process and the condition must be reoptimized for the improvement of RTL quality.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.189-196
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• 2007

Allometry, basal area equations, and volume equations were developed with various tree measurement variables for the major species, Quercus mongolica and Quercus variabilis, in Korean natural hardwood forests. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, crown width) and relative size (relative diameter, relative height) as well as competition measures (competition index, crown class, exposed crown area, percent exposed crown area, live crown ratio). For tree volume equations, the combined-variable and Schumacher models were fitted with DBH, total height and crown width for both species.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.197-202
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• 2007

This study is conducted to investigate the factors affecting lumber conversion rate of sawmill industry in South Korea. Data were obtained from the survey of 38 sawmills in all geographic regions of South Korea. The variables examined in this study were region, softwood/hardwood log, domestic/imported/both log, the number of power-driven carriages (PDC) installed, the year when and country where PDCs was manufactured, the horse power of PDC, the number of labors required to operate each PDC, the sawing capacity of mill (mill size), and the types of major product and by-products. The lumber recovery factor (LRF) of sawmills were significantly influenced by the origin of logs, level of PDC automation, sawmill size, and size of logs (measured in diameter and length) while not by the location of the mill, types of major product and by-product, log species, and characteristics of PDC. Although these results provide useful information for understanding the technological characteristics of the Korean sawmill industry, further investigation with larger sample is necessary to reveal the more reliable characteristics of sawmill industry in South Korea.

• Journal of architectural history
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• v.16 no.1
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• pp.9-28
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• 2007

We investigated the changes in the species of the woods used for Korean ancient and historic architectures, which include prehistoric excavated relics and existing wooden buildings in South Korea. The species data were collected from various sources such as excavation and repair reports, journal papers, and a few unpublished documents. We divided the building Periods as Paleolithic, Neolitic, Bronze Ages, Iron Age/Three Kingdoms, Koryo, Joseon (early, middle, late) and modem periods. In prehistoric periods, hardwoods were major species. Oak (Quercus spp.) woods dominated (94 percent in average); the others (5%) were Juglans mandshurica, Platycarya strobilacea, Castanea crenata, and few softwoods(1%). During Iron Age and Three Kingdom periods, oaks remained as a major species (57%) and others Platycarya strobilacea(21%), Castanea crenata(13%), and Pinus spp. (6%). The oak woods decreased in Koryo period and they occupied only 1.1%. Instead of oaks, pine (Pinus spp., 71%) and Zelkova serrata (22%) dominated in Koryo. In early and middle Joseon periods, pine woods (73%) remain as a major species and the others were oaks (14%) and Zelkova serrata (9%). As late Joseon came, the pine woods occupied more than 88%. In the late 19th and early 20th centuries, a few boreal species such as larch (Larix spp.) and spruce (Picea spp.), which grow in cold area, were found. We believe they were transported from northern Korea. The existing buildings in Korea are mainly from Joseon period and a few from late Koryo periods. During these periods, pine woods were used for most buildings. For such reason, pine woods were known as 'representative materials for historic buildings'. but earlier times, broad-leaved trees, i.e., oak and Zelkova woods were major materials. The changes in building materials resulted from both climate and human impacts. The dry climate and disturbed forests induce more pines in the mountains. We also compared the wood qualities of the species and found that Zelkova woods were superior ones and deserved more planting for future demands in the repair for historic buildings.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.635-645
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• 2014

The anatomical characteristics of eight major wood species planted in Indonesia were investigated to provide valuable information for their effective utilization. The growth-ring boundaries of Damar and Sumatran pine were indistinct. Resin canal was found in Sumatran pine but it was not observed in Damar. Cupressoid pit and taxodioid pit were found in Damar and window-like pit and pinoid pit were observed in Sumatran pine. Tracheid length of Damar and Sumatran pine was shorter than $3,000{\mu}m$. There were uniseriate rays in Damar and Sumatran pine and fusiform ray in Sumatran pine. All the hardwood species observed in this study were diffuse-porous. They had different vessel groups, i.e., solitary pore in Afrika and Simpur Batu, pore cluster in Angsana and mostly 2-4 rows of radial pore multiple in Mahoni. Mindi and Trembesi had mostly 2-3 rows of radial pore multiple with paratracheal parenchyma as aliform and confluent types. Afrika, Mahoni and Simpur Batu showed heterocellular rays which composed of procumbent cells in the body and mostly 1-2 rows of upright and/or square cells in the margin. All ray cells procumbent was observed in Angsana, Mindi and Trembesi. The large rays commonly exceeding 1 mm in height and ray width of 3~6 cells were observed in Simpur Batu. The other five hardwood species showed ray width of 1~3 cells. Vessel number per $mm^2$ of Angsana and Simpur Batu was higher than those of the other hardwood species. The length of wood fiber and tracheid showed a tendency to increase from pith to bark. By IAWA list, fiber length of hardwoods was classified into long in Simpur Batu and short in Angsana and Trembesi.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.4
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• pp.43-50
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• 2008

Adsorption of xylans extracted from birchwood and oat spelt on Hw-BKP were analyzed using HPLC. The effect of xylan adsorption on paper properties such as tensile, tear index and brightness was also investigated. The constituents of xylan was analyzed with HPLC after hydrolysis with dilute sulfuric acid. It was shown that xylose was the major constituent and small amounts of glucose and galactose were contained in the xylan samples. Adsorption of xylan on hardwood fibers was evaluated using acid hydrolysis and HPLC techniques. Results showed that the adsorption of negatively charged xylan on the fiber surface was negligible probably because electrostatic repulsion between these two materials. Pretreatment of the fiber with alum increased xylan adsorption. The amount of adsorption increased up to 30 mg/g. With the increase of xylan adsorption both tensile and tear strength of the handsheet increased suggesting xylan can be a very effective strength agents for papermaking. Brightness of the handsheets decreased, however, with the use of xylan.

• Animal cells and systems
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• v.12 no.2
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• pp.101-108
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• 2008

Recently, Platypus koryoensis has been reported as a major pest of oak trees in Korea which can introduce the pathogenic fungus(Raffaelea sp.) by making galleries into the heartwood of the tree. As the beetle has developed its effective drilling mouthpart enough to make tunnels, we have analyzed the fine structural aspects of the mouthpart using the field emission scanning electron microscopy(FESEM) to reveal its mechano-dynamic characteristics. The mouthparts of this ambrosia beetle which consist of a labrum, a pair of mandibles, a pair of maxillae and the labium exhibit typical morphology of mycophagous coleopteran beetles and have those characteristics of chewing mouthparts that can excavate galleries in the hardwood. Both of maxillary and labial palpi have the functions of direct the food to the mouth and hold it while the mandibles chew the food. The distal ends of these palpi are flattened and have shovel-like setae. Females have larger maxillary palpi and a larger gular region than males in general.

• 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.

• Journal of the Korean Wood Science and Technology
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• v.19 no.4
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• pp.34-42
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• 1991

Protection of tropical forest affects on significant reduce of tropical hardwood supply, and softwood resources will be increasingly important for the timber security in Korea. U.S. softwood log was most favorite species for Korean softwood log importers in overall import conditions except price stablization and consistency of export policy. Reduced export volume from Pacific Northwest to Korean market has been immediately replenished by rediata pine from New Zealand and Chilean plantation. Siberian timber will hardly play major roles in Korean timber market unless budding structure. softwood plywood and softwood furniture uses are enhanced. Recent rapid rise of labor cost and reducing tariff rrate in Korea provided better opportunities for import lumber in building materials market. Dry dimension lumber was relatively profitable when processed from import U.S. soft-wood log while green lumber was favorable products processed from radiata pine log in Korean lumber market. This means U.S. softwood lumber would have better opportunity to market for '2${\times}$'4 studs when wood frame housing is introduced. On the other hand while radiata pine is competitive on temporary construction lumber such as supporter and concrete forming frame in Korea. Shortage of raw material for the new capacity of board plants in Korea will be it bottle neck. Major log export countries to Korea as U.S. New Zealand and Chile showed high trade intensity indices of composite hoard produces for Korean market. As Korea efforts to diversify import sources, and tariffs are reduced to 8% as scheduled by 1994. countries of scoring higher comparative advantages as Portugal. Brazil, Austria as well as New Zealand will have better opportunity to penetrate into promised Korean composites hoard market.