• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.1-6
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• 2007

Boiling-in-oil process was performed to investigate the high-temperature drying characteristics of 25, 50, and 70 mm-thick flat-sawn Douglas-fir lumber. Drying rates, moisture profiles and temperature profiles were monitored. Fully refined paraffin wax was used as drying agent and heated to $130^{\circ}C$. Average drying rates of 25, 50, and 70 mm-thick specimen were 11.6, 6.7, 5.0%/h, respectively. The moisture content differences between cores and ends were 1~2% in 25 mm-thick and 200 mm-long sample and over 10% in 50 mm-thick and 600 mm-long sample.

• Journal of Forest and Environmental Science
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• v.7 no.1
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• pp.7-21
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• 1990

Without scientific understanding of the phase change and the rejuvenation in woody perennials, many tree breeders have successfully rejuvenated and multiplied mature trees of some tree species, i.e., Eucalyptus, Pseudotsuga menziesii Sequoia sempervirens, Pinus radiata, Pinus pinaster, Quercus virginiana, Hedera helix, Juglans, apples, grapes, and so on. Practical techniques discussed to rejuvenate the old trees include grafting to younger stock, growth regulator treatment, pruning, repeated cutting, and in vitro culture. However, a combination of skills mentioned is recommended for rejuvenation of the mature propagation material. It is strongly required to develop a morphological and/or biochemical indicator system to judge the juvenility.

• Journal of the Korean Wood Science and Technology
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• v.20 no.4
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• pp.31-42
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• 1992

최근에 서로 다른 생장추세를 나타내고 있는 남(南)애리조나산(産) 침엽수 4수종(樹種)(Pseudotsuga menziesii, Pinus ponderosa, Pinus strobiformis, Abies concolor)의 연륜폭 연대기(年代記)로 부터 반응함수를 구하기 위하여, 표준화 방법을 면밀히 검토하였으며 시계열모델에 의한 사전(事前) 여과화(濾過化)(prewhitening)로 전생장량(前生長量)을 배제하는 것이 효과적인 것인지도 조사하였다. 전통적으로 사용되던 지수(指數) 또는 질선(直線)방정식에 의한 표준화가 대부분 성공적으로 적용되었으나 최근생장이 급격히 감소된 경우는 스플라인함수를 이용하는 것이 효과적이었다. 계절(季節)모델이 적용된 Pinus ponderosa의 경우를 제외하곤 사전여과화 전후(前後)의 반응함수간(間)에 뚜렷한 차이를 발견할 수 없었다.

• Journal of the Korean Wood Science and Technology
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• v.12 no.4
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• pp.3-10
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• 1984

In hot pressed wood of Pseudotsuga menziesii compressed to 0 - 50 percent at temperature 60 - $180^{\circ}C$, relative humidity conditions affecting dynamic Young's modulus of elasticity and internal friction were investigated. The results obtained are summarized as follows: Moisture absorption of the hot pressed wood decreased with increasing press temperature, but there was no effect on the amount of compression. Thickness swelling dereased with increasing press temperature, and increased with increasing amount of compression. In general, dynamic Young's modulus of elasticity showed a straight line with increasing specific gravity of specimens. Dynamic Young's modulus of elasticity decreased with increasing moisture content, but internal friction increased with increasing amount of moisture content. Dynamic Young's modulus of R specimens pressed in the radial direction showed hight values than T specimens pressed in the tangential direction.

• Journal of the Korean Wood Science and Technology
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• v.9 no.3
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• pp.24-30
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• 1981

This experiment was carried out to determine the drying time from green to oven dry and estimate the moisture content of wood, such as red lauan (Shorea Spp.), Douglas fir (Pseudotsuga menziesii), Birch (Betula platyphylla), and oak (Quercus aliena), at various thickness, paralleled to fiber, of specimen for M.C. by oven dry method (100-105$^{\circ}C$). The results obtained are summarized as follows: 1. The drying time from green to oven dry decreases as the thickness of specimen for M.C. becomes to be thined, and that time at 10mm thickness are 14 hrs, for birch wood and 24 hrs, for oak wood. 2. The relative formulae between thickness (X) of specimen for M.C. and drying lime (Y) from 12% to oven dry are showed in Fig. 3. 3. The M.C. based on the weight of specimen for M.C. at t% can be obtained from the formula (2), and the drying time to 1% are shorter than that time to oven dry by approximately three times.

• Journal of the Korean Wood Science and Technology
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• v.49 no.6
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• pp.574-590
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• 2021

International efforts to prevent illegally logged wood are expanding around the world. The "Legal Wood Trade Promotion System" was enacted in Korea in 2019 to strengthen the legal import and distribution of commercial wood in Korea. Since then, this system has promoted and ensured that the imported wood and wood products are legal with respect to the country of origin, wood species, and harvested area. As verification methods, DNA analysis technology and anatomical analysis using a microscope are mainly used in conjunction. Therefore, in this study, wood species of plywood were identified by analyzing the anatomical characteristics of various wood products for the first time. Douglas fir (Pseudotsuga menziesii (Mirb.) Franco.) and larch (Larix kaempferi (Lamb.) Carriere) plywoods (7, 9 ply) were obtained from four companies that supply plywood in Korea. After cutting each company's plywood to a size of about 1 cm³, the layers from top to bottom were separated into single layers, and three sections were observed using an optical microscope. The results revealed that the plywood was composed of a mixture of softwood and hardwood wood species, pine wood species, poplar wood species, or a mixture of larch and pine wood species. Identification of wood species using microscopy is important and can enable the scientific analysis and verification of various wood products, including plywood, imported from countries where the likelihood of indiscriminate distribution of illegal wood and illegal logging is high.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.463-469
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• 2000

Douglas-fir (Pseudotsuga menziesd Mirb. Franco) is highly regarded as a commercial timber species throughout the world in part due to its fast growth relative to many other species. In this study, basal area per hectare equation for Douglas-fir plantations in Southland of New Zealand has been developed based on medium measurement cycles of permanent sample plots data set. The function was developed using the algebraic difference equation method, and various sigmoid-shaped projection equations were used. Parameter estimation was obtained by non-linear routine of the SAS. As a result, of the functions tested a variant of the Schumacher polymorphic function including site index and thinning term as predictor variables showed the higher precision of the fitting. The results indicate that site index is positively correlated with basal area growth. And the thinning term was found to be useful to increase precision of the model.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.100-106
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• 2006

A hypertonic solution of sorbitol was used to precondition Douglas-fir and Western hemlock plug seedlings to improve desiccation resistance. Seedlings were preconditioned by soaking their root balls in water, -0.75 or -1.50 MPa sorbitol solution for 22 hr, and then exposed to desiccation conditions for 8 days. During the desiccation period, a transpirational water loss was significantly reduced by the sorbitol preconditioning, with its effect positively depending on concentration. This preconditioning-induced reduction in water loss was mainly caused by the decline in needle stomatal conductance. Sorbitol-induced stomatal control was more closely associated with reduction in plant water potential, rather than increase in abscisic acid concentrations. After rehydration of stressed-plants, most of the preconditioned seedlings with sorbitol were survived, while only 35% of Douglas-fir and 28% of Western hemlock seedlings treated with water were alive. The post-growth was significantly greater in the preconditioned seedlings than only water-treated seedlings. These results suggested that the earlier stomatal control with sorbitol-facilitated preconditioning could play a role in improving desiccation resistance of evergreen woody plants at transplanting in the field where water supply is limited or dry conditions are prevailing.

• Journal of Mushroom
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• v.4 no.1
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• pp.39-42
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• 2006

Cauliflower mushroom(Sparassis crispa) contains much amount of ${\beta}$-glucan, which make lots of farmer want to cultivate the mushroom. Since a practical cultivation method is not provided yet, the mushroom is considered as a difficult crop to deal with. In this study, we tried to develope a simple method to cultivate the mushroom by use of coniferous sawdust-based medium with wheat flour and molasses. There was no significant differences between the sawdust spawn and the liquid spawn for the mycelial growth of the mushroom. The cold shock in $4^{\circ}C$ for a day was thought to be the best way to seduce primordium formation. The sawdust medium of Pseudotsuga menziesii mixed with wheat flour, corn chip, cottonseed meal and 10% molasses was showed the best yield with 41% followed by that of Larix leptolepis mixed with the same additives with 37% of yield. There was good relations between the fruit-body production and the weight loss of the sawdust substrate.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.61-70
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• 2003

The size distribution of the free water paths between earlywood and latewood for six species in the heartwood of softwoods was estimated from the amount of dehydrated free water under various centrifugal fields, such as 2,200, 3,300, 4,800 and 6,900 rpm. The centrifugal method is based on the concept that water movement occurs by the balance of centrifugal force and water potential by meniscus. Water stops where the pressure differential is zero. In the centrifugal field, only two factors affect water movement in wood, that is, centrifugal force and water potential. Also, the water permeability was evaluated from the relationship between the water saturation ratio after the centrifugal treatment and the measure of water potential in specimen. The results showed that Cryptpmeria japonica had clear peaks at 0.70 ㎛ in earlywood and at 0.50 ㎛ in latewood. Tsuga sieboldii and Larix kaemferi had peaks at 0.50 and 0.30 ㎛ in both earlywood and latewood, respectively. Abies firma showed peaks at 0.70 ㎛ in earlywood and at 0.30 ㎛ in latewood. The water permeability of earlywood was higer than that of latewood for all softwoods except Pseudotsuga menziesii.