• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.311-319
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• 2015

Near infrared (NIR) reflectance spectroscopy was employed to develop moisture content prediction model of pitch pine (Pinus rigida), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), yellow poplar (Liriodendron tulipifera) wood below fiber saturation point. NIR reflectance spectra of specimens ranging from 1000 nm to 2400 nm were acquired after humidifying specimens to reach several equilibrium moisture contents. To determine the optimal moisture contents prediction model, 5 mathematical preprocessing methods (moving average (smoothing point: 3), baseline, standard normal variate (SNV), mean normalization, Savitzky-Golay $2^{nd}$ derivatives (polynomial order: 3, smoothing point: 11)) were applied to reflectance spectra of each specimen as 8 combinations. After finishing mathematical preprocessings, partial least squares (PLS) regression analysis was performed to each modified spectra. Consequently, the mathematical preprocessing methods deriving optimal moisture content prediction were 1) moving average/SNV for pitch pine and red pine, 2) moving average/SNV/Savitzky-golay $2^{nd}$ derivatives for Korean pine and yellow poplar. Every model contained three principal components.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.359-374
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• 2010

This study was carried out to investigate the chemotaxonomical correlation and chemical constituents of domestic Quercus spp. barks. The barks of Q. mongolica, Q. aliena, Q. serrata, Q. acutissima, Q. dentata, and Q. variabilis were collected in the experimental forest of Kangwon National University. The combined extracts were successively fractionated with n-hexane, methylene chloride and ethyl acetate using a separation funnel. A portion of the ethyl acetate and H2O soluble materials of each species were chromatographed on a Sephadex LH-20 column using various aqueous MeOH and EtOH-hexane as washing solvents. Spectrometric analysis such as NMR and MS, including TLC, were performed to characterize the structures of the isolated compounds. Ellagic acid (0.03 g), (+)-catechin (4.59 g), taxifolin (3.35 g), and glucodistylin (20.52 g) were isolated from Q. mongolica bark. Gallic acid (0.18 g), (+)-catechin (8.52 g), (+)-gallocatechin (0.09 g), taxifolin (0.54 g), and glucodistylin (3.28 g) were characterized from Q. acutissima bark. Gallic acid (0.38 g), ellagic acid (0.11 g), (+)-catechin (2.01 g), (+)-gallocatechin (0.12 g), and glucodistylin (0.39 g) were identified from Q. dentata bark. Ellagic acid (1.51 g), (+)-catechin (21.91 g), and glucodistylin (3.91 g) were purified from Q. aliena bark. Ellagic acid (0.84 g), (+)-catechin (0.82 g), taxifolin (4.02 g), and glucodistylin (21.50) were isolated from Q. serrata bark. Gallic acid (0.24 g), caffeic acid (0.05 g), (+)-catechin (0.32 g), and glucodistylin (0.65 g) were purified from Q. variabilis bark. (+)-Catechin and glucodistylin were isolated from all the barks. Glucodistylin can be a taxonomic index on Quercus spp.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.26-37
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• 2012

Recently, the demand and supply on the Hanok have been increased. However, Hanok should be requested larger section of structural members because of excessive roof weight. So, structural skin-timber was manufactured to get a lightweight structural member. The structural skin-timber has exterior shape with larger section but a great volume of wood be removed. The reduced strength of structural skin-timber can be supplemented by hybridizaion of structural member. Japanese larch and Domestic pine were used to manufacture the structural skin-timber. Structural skin-timbers of rectangular shape and cylinder shape were manufactured and tested to evaluate the bending properties. The intended strength property could not be obtained because member had been suffered severe damage by precision deficiency of manufacturing machine. However, if precision of manufacturing machine would be improved and additional hybridizaion of structural skin-timber would be done, lightweight structural member will be able to be manufactured. Structural skin-timber did not showed statistical significancy between two species, so it is possible to use pine mixed with larch. Only MOR of larch showed statistical significancy between rectangular shape and cylinder shape, so it is necessary to use of those as separate things. However, the rest of skin-timber can be judged mixed using because of non statistical significancy. The objective of this study was the development of lightweight larger structural member with relatively strength. If hybrid member of skin-timber could be developed with wood-ceramics, lightweight steel and more, it can be possible to be used as a building material of Hanok, interior material, post & beam construction material and more.

• Journal of the Korean Wood Science and Technology
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• v.29 no.2
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• pp.140-145
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• 2001

Antimicrobial and antioxidative activities on heartwood extractives of domestic species were investigated to develop a natural fungicide or preservative. Six flavanones including pinostrobin, eriodictyol, naringenin, pinocembrin, taxifolin and verecundin were isolated from Prunus sargentii which has been selected due to its high antimicrobial and antioxidative activities among the tested species. According to the results of antifungal test, pinocembrin was evaluated as the highest antifungal compound among the test compounds, which showed 80% of hyphal growth inhibition rate. Antifungal activity of pinocembrin was similar to hinokitiol(${\beta}$-thujaplicin), strong antimicrobial compound isolated from Thujopsis dolabrata. Naringenin followed pinocembrin in its antifungal activity. However, verecundin did not show any antifungal activity. No compound was effective in antibacterial activities. As a result of the measurement of free radical scavenging activity, antioxidative activities of taxifolin and eriodictyol were 2 times that of ${\alpha}$-tocopherol, and antioxidative index of these compounds were even superior to that of ${\alpha}$-tocopherol. In this regard, it could inferred that high antifungal and antioxidative activities of extractives of P. sargentii were derived from pinocembrin, taxifolin and eriodictyol, respectively.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.51-57
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• 2002

Antimicrobial and antioxidative activites on heartwood extractives of domestic species were investigated to develop a natural fungicide or preservative. One steroid, stilbene derivatives and two flavonoids were isolated from heartwood of Robinia pseudo-acacia which has been selected due to its high antioxidative activity among the tested species. The structures were determinded as: 3-𝛽-stigmast-5-en-3-ol(daucosterol), 3,3'4,5-tetrahydroxystilbene, 3,3'4'5,7-pentahydroxyflavone(robinetin) and 3,3'4'7-tetrahydroxyflavanone(fustin) respectively on the basis of spectroscopic data and chemical correlations. According to the results of free radical scavenging activity, 3,3'4'5,7-pentahydroxyflavone was evaluated as the highest antioxidative compound among the four compounds and showed higher radical scavenging activity than those of 𝛼-tocopherol and butylated hydroxytoluene(BHT), one of the strongest synthetic antioxidants. 3,3'4'5-Tetrahydroxystilbene and 3,3'4'7-tetrahydroxyflavanone showed higher antioxidative activities than that of 𝛼-tocopherol. However, 3-𝛽-stigmast-5-en-3-ol did not show free radical scavenging activity. In this regard, it could inferred that high antioxidative activity of extractives of R. pseudo-acacia was derived from 3,3'4'5'7-pentahydroxyflavone, 3,3'4'5-tetrahydroxystilbene and 3,3'4'7-tetrahydroxyflavanone.

• Journal of the Korea Furniture Society
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• v.16 no.2 s.30
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• pp.59-65
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• 2005

As physical condition of students improves, there is a need to develop human body-friendly desk and chair for students. In this study, desks and chairs were manufactured with curved veneer lamination under high frequency heating and pressing, using ten wood species such as Japanese red pine, Korean pine, pitch pine, Japanese larch, yellow poplar, black locust, oak, radiata pine, beech, and birch. The performance of these products were evaluated. The results obtained were summarized as follows; With high frequency heating, the turned lamination of veneers with full size sheet ($3{\times}6\;feet$) prepared by rotary lathe peeling was successfully applied for making the members of desk top, leg frames of desk and chair. Bending strengths of desk tops were relatively greater for yellow poplar, black locust and red pine, which were similar to those of beech and birch. Bending strengths of desk legs were classified into greater species group (red pine, yellow poplar, larch) and lower species group (radiata pine, Korean pine, pitch pine). Compressive strengths of chair legs in parallel direction to the lamination were greater in black locust and larch. On the other hand, differences between outer and inner gap at the top and drawer bottom of desk top were rather larger for the laminations of birch and beech, and less for those of yellow poplar and pitch pine, showing greater stability of open drawer space. In results, yellow poplar, larch, pitch pine and red pine showed good appearance and strength properties at the curved veneer lamination. Accordingly, it was believed that these domestic woods were able to substitute for birch which was being imported for the use of veneer-laminates type furniture.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.203-210
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• 2001

In order to environmentally use wood chips manufactured from low valued forest resources by forest tendering, wood chips were used for the evaluation on chips characteristics, decomposition capability of organic wastes, and field experiment and determination of conditions for decomposer. Bioclusters manufactured by Cryptomeria japonica, commercially available wood chips in Japan, showed higher pore ratio, water reservation and water resistance, and higher cellulose content with lower hot water solubles than domestic wood chips. The useful size of wood chips for swine manure decomposition was 10 (length) ${\times}$ 5 (width) ${\times}$ 2 (thickness) mm, and cellulose contents and alkali solubles of Pinus densiflora and Populus tomentiglandulosa were similar to those of bioclusters. According to the decomposition ratio depending on wood species, it was ordered as Pinus densiflora > Pinus koraiensis > Cryptomeria japonica. The swine manure decomposition ratio depending on treatment hours by Pinus koraiensis was constant with the ratio of 15 to 16 g per hour by 1 kg of chip, indicating of daily swine decomposition amount of 390 kg by 1 ton of chips which was equal to the amount of daily swine manure production by 70 swines. Analyzing by long term used wood chips during 40 days treatment, the treated wood chips characteristically showed stable total nitrogen content, suitable pH, high accumulation of inorganic contents such as calcium, phosphorus, potassium and sodium, and no odor. During winter, the inner temperature of decomposer was kept at $43^{\circ}C$, but air bubble was occurred due to high pH and viscosity of swine manure. The most appropriate mixing ratio between wood chips and swine manure was 1 versus 2 or 3, and at more than ratio 1 versus 3, ammonia gas was caused because of anaerobic fermentation status by high moisture content of wood chips. The mixing interval of decomposer was 3 mins. per hour for the best swine decomposition.

• Journal of the Korean Wood Science and Technology
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• v.18 no.1
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• pp.39-51
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• 1990

This research was carried out to offer the basis data for development of optimum drying schedule for a domestic oak species (Quercus grosseserrata B1.) by investigating drying rate. stress, defect, and moisuture gradient with board thicknesses and drying schedules (code number T4-C2 and T3-B1). The results were obtained as follows: 1. Average drying rate and total drying time from 52.2% to 5.8% were 0.105%/hr and 486 hours for drying schedule T4-C2 and those from 62.1% to 8.3% were 0.070%/hr. and 811 hours for drying schedule T3-B1. 2. Drying rates for 28mm- and 31mm-thick boards showed similar tendency, but were significantly different from 25mm- thick board in drying schedule T4-C2 and those for 22mm-, 25mm- 28mm- and 31mm-thick boards showed similar tendency but were significantly different from 19mm- thick boards in drying schedule T3-B1. 3. The moisture gradients for drying schedule T4-C2 were steeper than those for drying schedule T3-B1 during drying period. and especially in early drying stage slow slope of moisture gradients of drying schedule T3-B1 was effective in preventing serious problem of surface checks. 4. Drying stresses were lower in drying schedule T3-B1 than in drying schedule T4-C2 during drying period. 5. Drying schedule T4-C2 was appropriate for 25mm-thick board but not for 28mm- and 31mm-thick board because of strong drying condition. Drying schedule T3-B1 was appropriate for 28mm- and 31 mm-thick board but not for 19mm-, 22mm-, and 25mm-thick board because of weak drying condition.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.271-278
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• 2002

Methanol extracts from 420 samples of 173 plant species in 58 families were tested at 5000 ppm for their insecticidal and acaricidal activities against five economically important arthropod pests by spray method. The responses varied with arthropod pest species, plant species and plant tissue sampled. In a test with Nilaparvata lugens Stal, extracts from Zanthoxylum piperitum barks, Chamaecyparis obtusa leaf and Quercus salicina leaf showed potent insecticidal activity. With Plutella xylostella L., potent larvicidal activity was observed from extracts of Platycarya strobilacea wood, Meliosma myriantha barks, Sophora japonica leaf, Zanthoxylum piperitum barks, and Pinus thunbergii wood. Methanol extracts of Sophora japonica leaf and Zanthoxylum piperitum barks showed high insecticidal activity against Spodoptera litura. In a test with Tetranychus urticae Koch, extract from Carpinus coreana leaf, Firmiana simplex barks, Elaeagnus macrophylla leaf, Aralia elata leaf, Comus controversa barks and Chamaecyparis obtusa leaf exhibited strong acaricidal activity. As a naturally occurring pest control agent, Zanthoxylum piperitum barks could be useful as new insecticidal and acaricidal products against various arthropod pests.

• Journal of the Korean Wood Science and Technology
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• v.13 no.3
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• pp.41-48
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• 1985

In near future about 500,000 hectares of Japanese larch and pitch pine need thinning to improve crop-tree spacing and reasonable species composition in Korea. Although thinned trees show very little high quality wood, in fact, all the sawed products are suitable for construction and farming materials. Studies on the utilization of thinned small-diameter trees have been implemented in order to increase lumber yield and display the skeleton of farm buildings. The results obtained in this study were summarized as follows: 1. According to Korean Conifers Log Grading System, log grade 3 was 87.4 percent in Japanese larch bolts and 95.8 percent in pitch pine bolts from thinned trees. The ability to identify defects was essential for grading logs. 2. Cutting diagrams of sawing were developed for 1-sided sawing, 2-sided sawing and 3-sided sawing by small end diameter class of bolt and cutting sizes also were found to use effectively lumber with wane. 3. Lumber recovery of Pitch pine was a little higher than that of Japanese larch. The maximum lumber yields of pitch pine by sawing patterns were 87.2 percent for 1-sided sawing, 80.8 percent for 2-sided sawing an 64.1 percent for 3-sided sawing, up yield compared with 58.1 percent for 4-sided sawing. The lumber yield of 1, 2 and 3-sided sawing significantly was higher value than that of 4-sided sawing. 4. Lumber was inspected and graded. Lumber quality of diameter class 12cm was a little better than that of diameter class 8cm, but 90 percent of lumber in diameter c1ass 16cm fell into grade 3. The lumber grade was classified by Korean standard grades of confiers lumber. 5. Lumber from 1, 2 and 3-sided sawing was used to build the skeleton of a farm house ($53m^2$) and greenhouse ($60m^2$) in order to display more efficient use of small diameter trees from thinning 6. Total volume of timber for building a farm house was $8.1m^3$ of imported timber. Timber of $7m^3$, 70 percent of total volume would be substituted imported timber for domestic timber.