• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.52-60
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• 2003

The physical properties of small hardwood and softwood specimens treated with liquid ammonia were investigated. The specimens treated for 4 or 18 hours were compared with the controls. The EMCs of the liquid ammonia treated specimens were higher than those of the controls when conditioned at the same humidities. However once oven-dried they didn't show any significant differences in EMCs. With the increase of liquid ammonia treatment time specimens shrank in radial and tangential directions, but not in longitudinal direction. As liquid ammonia treatment time increased the ultrasonic velocities of specimens decreased and their densities increased, thus their dynamic MOEs decreased. For chestnut specimens the presteamed were more plasticized than the liquid ammonia treated. Incising on the surfaces of specimens didn't improve liquid ammonia permeability in both hardwoods and softwoods. Liquid ammonia treatment was very effective for plasticizing 5 mm thick softwoods. Relative dielectric constants and thermal conductivities were measured with both liquid ammonia treated and control specimens.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.33-40
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• 2002

This research was to investigate the adsorption characteristics of charcoals of major Korean wood species (thinned trees) and wood-based materials. As carbonization time and temperature increased, methylene-blue adsorption (MBA) of charcoals of thinned trees and wood-based materials increased. Pinus koraiensis charcoal showed the highest MBA. MBA of softwoods was higher than that of hardwoods. There was a negative correlation between air-dried specific gravity before carbonization and MBA of carbonized thinned trees. The MBA of wood-based materials showed similar value, but wood-based materials in MBA was lower than thinned woods. Surface area and total pore volume of thinned trees and wood-based materials increased as carbonization temperature increased. The species showing highest MBA appeared to have the highest surface area at the carbonization temperature of 600℃ as well. There was a positive correlation between surface area, total pore volume and MBA of charcoals. The charcoal of wood-based materials generally exhibited micro pores.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.281-290
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• 2011

We analyzed the basic characteristics and adsorption property of carbonized materials from thinning byproducts of major Korean wood species for evaluating as charcoal making raw material. Yield of charcoal was decreased with increasing the carbonization temperature for all wood species. Refining degrees was 9.0 at $400^{\circ}C$, 3.3~5.0 at $600^{\circ}C$ and 0 at $800^{\circ}C$, and was no difference among wood species. With increasing the carbonization temperature, the fixed carbon content was also increased, and charcoal from softwoods had more fixed carbon content than that from hardwoods. Specific surface area was increased with increasing the carbonization temperature, softwood charcoal had more specific surface area than that of hardwood. Pinus rigida showed the highest specific surface area. In formaldehyde removal by charcoal, some materials had highest at $600^{\circ}C$ and the others had highest at $800^{\circ}C$. Pinus koraiensis, Qurcus acutissima and MDF showed maximum formaldehyde removal ability at $600^{\circ}C$. Ethylene gas removal ability of charcoal was increased with increasing the carbonization temperature, and the charcoal from Pinus rigida and Robinia pseudoacacia had higher ethylene gas removal ability than the other species.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.57-66
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• 2016

In order to develop materials with a low environmental load for restoring the destroyed forest, seven types of wood-concrete hybrid laminated materials were manufactured with four softwoods, three hardwoods and concrete, and the effect of wood density on bending creep property was investigated. The bending creep curves showed a shape to considerably increase at the upper right side, and the curves were found to show a linear behavior beyond about 30 min - 1 hour, as behaviors of solid woods and wood-based materials. The initial compliances of wood-concrete hybrid-laminated materials decreased with an increase in the wood density, and those values showed 0.9 - 1.2 times of the concrete one. The creep compliances of hybrid laminated materials showed very low values, which were 0.4 - 0.8 times of the concrete ones. The relative creep were very low with a range from 8.2% to 17.0% range, which were 0.3 - 0.7 times of the concrete ones. These results indicate that these materials can be applied for restoring the destroyed forest to reduce creep deformation of the conventional concrete materials by hybrid-laminating concrete and woods.

• Journal of Korean Society of Forest Science
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• v.76 no.2
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• pp.119-126
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• 1987

This study was carried out to elucidate the desirable PEG molecular weight and it's blending methods which can promote the dimensional stabilization of Corpus controversa, Quercus variabilis and Prunus sargentii. The results may be summarized as follows: 1. PEG polymer loading in woods was affected by specific gravity of wood. And the PEG polymer loading was satisfactory except in Quercus variabilis, which shows the blending method of PEG V was proper. 2. Bulking coefficiency of PEG V was high in Corpus controversa and Prunus sargentii, and it is necessary to paint or coat water-proofing wood preservative: for high bulking coefficiency of Quercus variabilis. 3. In the treatment of PEG V, the antishrink efficiency of Prunus sargentii was 82.59% and that of Quercus variabilis 62.79%. 4. Dimensional stabilization of hardwoods did not have apparant relation with PEG blending method. 5. Judging from results, PEG-400 and PEG-1000 would be enough for dimensional stabilization of hardwood having high specific gravity if other factors are considered well.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.42-47
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• 2016

To examine the natural regeneration in the natural mixed-broadleaved forest, flowering, fruiting, seed-fall, and seed viabilities of Acer pseudosieboldianum (Ap) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2015. The flower of Ap consisted many male and bisexual flowers on the corymb. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of Ap might be pollinated by Apis mellifera, Andrenidae spp. and Syrphinae spp. Ap had some mechanism to prevent from self pollination with heterodichogamy. Mean annual seedfall of Ap was 70,780 ea/ha (ranged 310~234,840 ea/ha). Annual seedfall of Ap varied severely, and the maximum was about 760 times the minimum. Annual seed production of Ap might be to a normal distribution. Rates of damaged or decayed seeds are highest 59.3%, and those of sound seeds are 23.9%, Those of undeveloped and empty seeds are 9.2% and 7.6%, respectively. The most important factors influencing sound seed production might be the density and activities of insect pollinators and sucking pest in the flowerwing period, middle-late May. Successful regeneration of Ap might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of deciduous hardwoods, further study on the characteristics of flowering and fruiting, pre- and post-dispersal seed predation, and annual variation on these factor should be needed.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.622-628
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• 2017

In order to develop value-added utilization technology of domestic oaks the processing yield rate from the standing tree to the flooring material for the Quercus variabilis and Quercus mongolica were investigated. Also, to reduce drying time, improved drying schedule was applied and the physical properties were measured. The drying time was 173 hours in total, and the final moisture content was 5.39% (Quercus variabilis) and 4.17% (Quercus mongolica). The color difference of oak lumber before and after drying showed a significant change as ${\Delta}E$ value from 7 to 11. The shrinkage rates of Quercus variabilis and Quercus mongolica during drying were 8.1% and 8.5% in the tangential direction and 5.0% and 6.2% in the radial direction, respectively. The lumber manufacturing yield rate of sawn lumber was 30 to 40% and that of the final product was 8 to 15%. It is expected that the processing characteristics of the Quercus species investigated in this research could contribute to formulate an efficient production plan of domestic hardwoods that are still under utilization.

• Journal of the Korean Wood Science and Technology
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• v.3 no.1
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• pp.3-15
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• 1975

How to stabilize wood against shrinking and swelling in variable atmospheric moisture conditions is important to the wood-using industry and a challenge to research. Polyethylene glycol stabilize wood by bulking the fiber. PEG also serve as a chemical seasoning agent, suppress decay in high concentrations, and have slight effect on physical properties, gluing or finishing. The study designed to determine the effect of PEG-400 on the dimensional stabilization of local hardwoods for wood carvings that could supply a greatly expanding tourist trade and making curved furniture parts, lamp stands and other decorative objects, and possible gunstock. The species examined were 6 species, Seo-Namoo (Carpinus laxiflora), Cheungcheung-Namoo (Cornus controversa), Gorosae-Namoo (Acer mono), Karae-Namoo (Juglans mandshurica), Jolcham-Namoo (Quercusserrata) and Sanbud-Namoo (Prunus sargentii), used as block of 5cm thick radially to the grain, 7cm wide tangentially, and 70cm long parallel to the wood grain. All these test piecies were conditioned above the fiber saturation point before impregnation. The stabilization effects were determined for PEG-400 treated woods in a 50 percent solution for 20 days. The following conclusions were obtained. PEG retentions increased with treating time. It was more effective to treat at 60$^{\circ}C$ than at room temperature. In degree of PEG-400 impregnation on species, Cheungcheung-Namoo havinglow specific gravity had the highest retentions, 68.77% but the lowest, 56.33% was shown in Jolcham-Namoo with high specific gravity. Specific gravity of treated wood increased considerably with effectiveness of polymer loading. The increases in specific gravity were 5.36 to 13.16 percent. The highest was Jolcham-Namoo, the lowest Karae-Namoo. On the dimensional stability, a 40 percent of effectiveness of polymer loading was just as effective as 60 percent in reduction in water absorptivity (RWA), antishrinkage efficiency (ASE) and antiswelling efficiency (AE), and from over 60 percent they increased more rapidly. Also species response varied considerably. ASE was 30.12 to 69.97 percent tangentially and 27.86 to 56.37 percent radially, AE 34.06 to 73.76 percent tangentially and 30.11 to 70.12 percent radially, and RWA 42.31 to 65.32 percent. No differences in volume swelling among the 6 species were observed. Its values were ranged from 14.98 to 19.55 percent and also increased with PEG retentions. On the mechanical properties, the strengths very much decreased with PEG-400 loadings as shown in Figure 12; that were 11.41 to 22.90 percent in compression, 21.61 to 34.35 percent in bending and 22.83 to 36.83 percent in tensile strength. PEG retention in cell wall was less than 1 percent and the most of PEG were immersed in cell lumen. Except for Korae-Namoo, effectivenesses of polymer loading were as much high as 61.58 to 75.02 percent. This is believed to be due to the effect of PEG-400 on excellant dimensional stability of treated woods.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.460-466
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• 2014

To evaluate wood charcoal as raw material for mineral water production, dissolution of inorganic ions from charcoal to water, pH and adsorption ability of chlorine in water were investigated as main variables. More potassium ion was dissolved in water as higher temperature manufactured charcoal but other ions showed no difference with different charcoal making temperatures. Highest dissolved cation was potassium followed by calcium and sodium. Among wood species, charcoal from Quercus variabilis and Platanus occidentalis showed significantly higher potassium content in water than that of larch, red pine and white pine. Other cations had similar pattern to the potassium but their difference was not apparent as much as potassium. pH value of water treated with charcoal was higher for wood charcoals from Platanus occidentalis (pH 8.5) and Quercus variabilis (pH 8.4) which contained higher inorganic cations. In chlorine removal in water by charcoal, all wood charcoals showed greater chlorine removal than that of the control, but softwood charcoals resulted in higher removal than those of hardwoods. There was no significant difference in the dissolution of cations and pHs between particle charcoal and whole charcoal. With easy of control, whole charcoal is better for mineral water making raw material than particle charcoal does.

• Journal of Forest and Environmental Science
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• v.30 no.4
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• pp.383-392
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• 2014

In this study, we investigated the Fukiage sand dunes of southern Kyushu, Japan. We surveyed the status of recovery of coastal Japanese black pine forests damaged by pine wilt disease and their disaster prevention capability. We placed two transects: Transect 1, in an area that was severely damaged (80-90% damage rate) by pine wilt disease, and Transect 2, in an area that was mostly undamaged (<10% damage rate). Then, we installed survey lines, carried out vegetation surveys, and measured the depth and pH of humus soil. The survey lines were placed perpendicular to the coastline from the top of the fore-dune to the inland area, and divided into five 50 m sections. Before the point 100 m inland from the top of the fore-dune, the number of invasive hardwoods and of Japanese black pines were small because of the poor growth environment in both transects. Past the 100 m point, the species and number of Japanese black pines and broad-leaved trees increased further inland because the growth environment improved. In addition, the recovery metrics of tree height, diameter at breast height, age, and number in Transect 1 were much lower than those in Transect 2, and the basal area of broad-leaved trees and the depth of humus soil in Transect 1 were lower than in Transect 2, and the soil pH of humus soil in Transect 1 was higher than that of Transect 2. The shape ratio of the Japanese black pine forests indicated that they were insufficient for disaster prevention. Therefore, in order to fully promote the disaster prevention capability of coastal Japanese black pine forests, we should not only focus on prevention of pine wilt disease but also undertake continuous control efforts taking into consideration the sound growth environment such as appropriate density and soil management and removal of invasive broad-leaved trees.