• Journal of Ecology and Environment
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• v.29 no.1
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• pp.17-22
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• 2006

Since the demands not only for value-added timber but the environmental functions of forests had been increased, native tree species has been, and is rapidly being replaced by foreign tree species in many parts of the world. However, the studies on population structure and regeneration characteristics of native tree species were not conducted enough. Regeneration of Kalopanax septemlobus growing among other hardwoods in natural forests is very difficult because of its low seed viability and germination rate. The study examined the distribution of mature trees of K. septemlobus and their regeneration pattern at the 1.12 ha study plot in natural deciduous broad-leaved forest of Mt. Jeombong. The density and mean DBH of K. septemlobus was 97 trees per ha and 32 cm, respectively. The spatial distribution of K. septemlobus showed a random pattern (aggregation index is 0.935) in the 1.12 ha study plot. The age of 90 trees among 99 sample trees of K. septemlobus ranged from 90 to 110 years and represented a single cohort, thus suggesting that K. septemlobus in advance regeneration has regenerated as a result of disturbances such as canopy opening.

• Journal of the Korea Furniture Society
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• v.23 no.4
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• pp.460-466
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• 2012

This study was conducted to investigate the surface hardness of thermally-compressed larch wood by compression set and temperature. The surface hardness of thermally-compressed larch wood increased with increasing compression set and temperature. For compression set 60%, the specific gravity was increased as 0.93. However, the surface hardness was lower value as 31.1 N/$mm^2$ compared with a similar specific gravity of the tropical timber. For density profile, less than compression set 40%, compression was observed mainly surface area. On the other hand, more than 50%, density profile variation was reduced by compression of central part. Results of this study indicate that thermally-compressed larch wood can be replace some imported hardwoods such as oak or cherry. However, thermally-compressed larch wood was difficult to replace the tropical timber being imported in terms of surface hardness.

• Journal of the Korea Furniture Society
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• v.20 no.5
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• pp.457-466
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• 2009

This study was carried out to investigate the physical and mechanical properties of 6 hardwoods before and after heat treatment in an effort to produce the high quality industrial lumber product. The results were as follows. Specific gravities of green woods were in range from 0.90 to 1.10. The specific gravities of never treated woods showed higher than those of the heat treated woods. The shrinkage of heat treated woods when green to air & oven dry was significantly low, compared to never treated woods. The compression strengths parallel to grain of heat treated woods showed higher than those of never treated woods. The moduli of rupture (MOR) of never treated and heat treated woods were $176.4N/mm^2{\sim}102.8N/mm^2$ and $100.1N/mm^2{\sim}61.2N/mm^2$ respectively. MORs of heat treated woods showed lower than those of never treated woods. There was no significant change in the modulus of elasticity (MOE) before and after heat treatment.

• Journal of the Korea Furniture Society
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• v.28 no.3
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• pp.233-247
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• 2017

Woodcraft activities have an inseparable relationship with our daily life, and it is a field that needs to be continued because of the value of education for the growing students. The interest in woodworking from childhood to old age is rapidly expanding nowadays, therefore this study has been done to provide images to those who are engaged in woodcraft business and also those who are interested in this field. If we look at the use of wood in our daily life, We can classify it into Architecture, Civil engineering, Furniture, Musical Instrument, Packaging, Recreational instrument, Exercise instrument, Stationery, Daily commodity, and Industrial use. Among them, We examined kinds of stationery and which type of woods were used. As a result of classifying 101 stationery products in 22 countries, stationery materials using wood can be used for Business cards, Envelope houses, Box houses, Pen holders, Locker plates, Stationery baskets, Book holders, Stamps, Paper knives, Bookmarks, and Photo frames. It was found various wooden stationery are made in USA, Japan, UK, Canada etc. And the most frequently used species are hardwoods such as Walnut (Juglans regia), Maple (Acer spp.), Cherry (Prunus serotina), Birch (Betula spp.), Mahogany (Swietenia macrophylla), Tulip (Liriodendron tulipifera Linnaeus), Bubinga (Guibourtia tessmannii J. Leonard), Wenge (Milletia laurentii De. wild), Cocobolo (Dallbergia cultrata Grah), Zebrawood (Microberlinia brazzavillensis A. Chev.) and Ebony (Diospyros spp.).

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.46-54
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• 2007

The purpose of this study was to examines the burning rate of fire retardant treated wood in the cone heater with a one-dimensional integral model. The wood samples used in this study were four species. The species of woods are Redwood, White oak, Douglas fir and Maple. Each sample was nominally 50mm thick and 100mm square. Samples were exposed to a range of incident heat fluxes 10 to $35kW/m^2$ using the cone heater. A one-dimension integral model has been used to predict burning rate, heat of gasification, flame heat fluxes, charring rate and char depth of samples. As a result measurement of mass loss rate, softwoods(Redwood and Douglas fir) has relatively low value than those for hardwoods(White oak and Maple). Average charring rate of woods in case of fire retardant treatment showed reduction effect of 41.29%, 50.00%, 48.18% and 60.82% for Redwood, Douglas fir, White fir and Maple, respectively. Almost all the predictions from integral model showed faster charring than those measured. Average difference between predictions and experimental data was 16%, 9.5% and 11.8% for N, F1 and F2 respectively. Water-soluble fire retardant used in this study find out more effect in hardwood than softwood from the result of measurement of mass loss rate and average charring rate.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.24-28
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• 1997

As a way to revive the traditional technology of Korean golden varnish(Hwangchill), the exudates of D. morbifera, this study was carried out at first to investigate the anatomical characteristics and the chemical composition of D. morbifera stems and their exudates. Trees of more than 20 years old were harvested at Wando and Jejudo islands in the southwestern part of Korean peninsula during different physiological seasons of winter, spring, and summer, The results obtained are as follows: 1. In the anatomical aspect of wood, Hwangchil woods is ring-porous wood, has alternate inter-vessel pittings and horizontal intercellular canal in xylem. 2. In the chemical aspect of wood and bark, the general compositions appeared hot to differ from those of other hardwoods, and ash and alcohol-benzene extractives showed little increase with the increase of atmospheric temperature of harvesting season. 3. In the solvent-sequential extraction of bark, wood and exudate, the exudates was extracted up to 80% by ether, but the bark and wood contained a very small amount of ether extractives, about 2% in the bark and 0.5% in the xylem.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.83-91
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• 2011

Hemicelluloses are useful materials for papermaking and other biotechnological applications. To recover and further utilize the hemicelluloses, this study carried out the pre-extraction of the hemicelluloses from Korean mixed hardwoods chips using hot water and sodium hydroxide solution at various temperature and time conditions. Through the hot water pre-extraction, the wood components of 22% was extracted and the 35% of the hemicelluloses which were contained in the original wood chips were dissolved into the pre-extractives. The yield of the pre-extractives was more significantly influenced by the pre-extraction temperature than the time. The pre-extractives with the yield of 30% could be obtained by alkali pre-extraction and alkali concentration was the most important factor. It had lower hemicellulose content but high molecular weight, compared with the hot water pre-extractives.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.317-321
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• 2006

The investigation of the formation of organic sulfur compounds (i.e., odor species), mainly methyl mercaptan and demethyl suifide, during kraft pulping has been conducted, in which both hardwood and softwood species were used. It was discovered that there is an organic sulfur compounds formation phase transition point with respect to delignification extent. The transition point occurs at a kappa number of approximately 35 and 20 for softwoods and hardwoods, respectively. The results also showed that both low sulfidity and anthraquinone (AQ) addition are helpful to control the formation of theses organic sulfur compounds during kraft pulping. Whereas Hexenuronic acid (HexA) has contribution to Kappa number, the extended delignification not only lead to low pulp yield, but also be adverse to odor control. A significant in-digester odor reduction can be achieved if the pulping is to be terminated before phase transition point and combined with AQ addition.

• Journal of the Korean Wood Science and Technology
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• v.49 no.5
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• pp.471-481
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• 2021

This study investigated the hygroscopicity and UV deterioration characteristics of 3 domestic and 4 imported woods using natural oil, stain, and varnish paints. In terms of hygroscopicity, it was found that the hygroscopicity of the painted wood was lower than that of the unpainted wood, and that as the number of coatings increased, the hygroscopicity decreased. In terms of anti-absorption, oil-based chemical paints showed higher resistance than water-based paints, and natural oils showed results comparable to oil-based paints. As for the UV deterioration, the amount of color change of the painted wood was lower than that of the unpainted wood, and there was no significant difference according to the number of times of painting. The amount of color change was found to be low in oil-based paints and hardwoods. Through this study, we confirmed effective moisture blocking and small color changes during painting using paints, and it is believed that wood can be protected from internal and external defects through selective and efficient painting based on data for excellent painting performance.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.1-11
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• 2008

The purpose of this study is to examine the species of wooden members used in the Youngsanjeon Hall of the Sucknamsa temple in Anseong, Korea. Ninety-five wood samples from pillars, head-penetrating ties, beams, corner rafter, rafter, floor board and other wood members were identified. Seven species identified were hard pine, exotic pine, Zelkova serrata, Ginkgo biloba, Diospyros, Quercus(Cerrus) and Pyrus spp. In the case of pillars, eight were hard pines and the others Zelkova and Pyrus. Species of angle rafter were Ginkgo biloba and Zelkova. and those of beams were one hard pine and one Zelkova. Two purlin samples were Quercus(Cerrus) and rafters were hard pines except one Ginkgo and one exotic pine. Roof-filling timbers were identified as Zelkova and Diospyros spp. The other samples of roof-filling timbers were all identified as hard pines. The use of Ginkgo and several hardwoods in addition to hard pines may indicate supply of local logs near the Sucknamsa temple.