한국목재공학회

DOI: JANT Vol.49(No.5) 1-1, 2021

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한국목재공학회

DOI: JANT Vol.49(No.5) 2-2, 2021

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Hye-ji Yoo , Jeong-deuk Ju , Jun-hui Park , Chang-seob Shin , Chang-Deuk Eom , Jeong-Wook Seo

DOI:10.5658/WOOD.2021.49.5.399 JANT Vol.49(No.5) 399-415, 2021

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This study was conducted to suggest the optimal periods for planting and felling Larix kaempferi tree by monitoring its cambial activity period. In addition, the heat summation to induce the cambial activity of Larix kaempferi was investigated. The study sites were at Mt. Worak and Mt. Midong. After selecting 5 trees at Mt. Worak and Mt. Midong, the cambium samples were collected using a mini trephor with 2 mm diameter from April 7 to October 6, 2017 at Mt. Worak, and from April 7 to September 29, 2017 at Mt. Midong. After the collected cambium samples were embedded in PEG2000, transverse thin sections with a thickness of 1 0 to 1 5 μm were prepared using a microtome. One Larix kaempferi sample from each site, Mt. Worak and Mt. Midong, in which the accurate monitoring of cambial activity was impossible due to the formation of traumatic resin canal, was excluded from the study. The observation of the initiation date of cambial activity under a light microscopy revealed that 2 specimens from Mt. Worak and 3 from Mt. Midong showed the initiation on April 28. The remaining 2 specimens of Mt. Worak and 1 specimen of Mt. Midong were initiated on May 4, which was a week later than the others. The heat summation that induced the initiation of cambial activity was 196.4－271.8 at Mt. Worak and 204.7－277.3 at Mt. Midong, which was similar. The termination of cambial activity occurred between August 4 and 25 at Mt. Worak, and between August 4 and September 1 at Mt. Midong. Based on the above results, it was found that the optimal planting period for Larix kaempferi in Mt. Worak and Mt. Midong was before April, about a month before the cambium activity, and the felling period was from October when the cambial activity was completely terminated.

Apri Heri Iswanto , Fazilla Oktaviani Tarigan , Arida Susilowati , Atmawi Darwis , Widya Fatriasari

DOI:10.5658/WOOD.2021.49.5.416 JANT Vol.49(No.5) 416-429, 2021

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Raru is a lesser-known plant species originating from North Sumatra, Indonesia. Information on the characteristics is still limited, especially its chemical component. Therefore, this study aims to examine the chemical composition information of Cotylelobium lanceolatum, Cotylelobium melanoxylon, and Vatica pauciflora woods based on their axial log positions (bottom, middle, and top). The wood chemical analysis was performed in terms of the Indonesian National Standard (SNI) method. Furthermore, the analysis measured holocellulose, α-cellulose, hemicellulose, lignin content, alcohol benzene extractive content, the extractive substance in hot and water, and solubility in NaOH 1%. The results indicated that the species and their log axial positions affected different chemical components, which included α-cellulose, hemicellulose, and lignin of C. lanceolatum amounting to 41.88%, 19.39%, and 28.68% respectively. Meanwhile, for C. Melanoxylon, they were 42.01%, 21.11%, and 24.76% respectively; and for V. pauciflora wood, they were 42.95%, 23.24%, and 30.11% respectively. The average values of the extractive contents including the solubility in 1: 2 ethanol benzene, NaOH, and hot water for C. lanceolatum, C. melanoxylon, and V. pauciflora wood were (10.58%, 27.62%, 8.13%), (14.54%, 28.22%, 7.82%), and (10.95%, 28.60%, 7.57%) respectively. The wood species had a significant effect on chemical components including lignin, cellulose and hemicellulose, and extractive solubility in cold water. Furthermore, the axial log position had a significant effect on all the parameters of the chemical composition of the wood being tested.

Yeonjung Han , Sang-min Lee , Jinyoung Choi , Chun-young Park

DOI:10.5658/WOOD.2021.49.5.430 JANT Vol.49(No.5) 430-452, 2021

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The recent social atmosphere has been a preference for wood utilization and woodworks. The general public does not have many opportunities to enjoy wood culture, so there is a lack of awareness and foundation of wood culture. In this study, classification and case analysis of wood culture were conducted as basic research for establishing a promotion strategy for the general public to enjoy wood culture. The specificity of wood culture and cultural resources was analyzed to establish the concept of wood cultural resources. Through the analysis, wood cultural resources were defined as products created as a result of human activities that implied the cultural value of wood and wood use in terms of conservation, discovery, and utilization. The types of wood cultural resources were classified into seven categories using the classification examples performed on cultural resources: cultural heritage, cultural facilities, cultural festival, wood architecture, culture contents, culture education, and wood products. In addition, cases were searched and proposed for each type of wood cultural resources.

Eko Setio Wibowo , Muhammad Adly Rahandi Lubis , Byung-dae Park

DOI:10.5658/WOOD.2021.49.5.453 JANT Vol.49(No.5) 453-461, 2021

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In wood-based composite panels, low-molar ratio (LMR) urea-formaldehyde (UF) resins usually result in reduced formaldehyde emission (FE) at the expense of poor adhesion. However, the FE and adhesion of medium-density fiberboard (MDF) bonded with LMR UF resins were both improved in this study. The modified LMR UF resins with transition metal ion-modified bentonite (TMI-BNT) nanoclay simultaneously improved the FE and adhesion of MDF panels. The modified LMR UF resins with 5% TMI-BNT resulted in a 37.1% FE reduction and 102.6% increase in the internal bonding (IB) strength of MDF panels. Furthermore, thickness swelling and water absorption also significantly decreased to 13.0% and 24.9%, respectively. These results imply that TMI-BNT modification of LMR UF resins could enhance the formation of a three-dimensional network rather than crystalline domains, resulting in improved cohesion.

Hyun Mi Lee , Jae Soo Bae

DOI:10.5658/WOOD.2021.49.5.462 JANT Vol.49(No.5) 462-470, 2021

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To find out the wood species used in national wood structures in the late Joseon Dynasty, 11 volumes of Yeonggeon-Uigwes were reviewed. It was confirmed that the wood was mainly used for the repair and restoration of palaces, shrines, and fortresses. In the 17th to 20th centuries, the wood species specified in Yeonggeon-Uigwes have revealed either hardwood or softwood. As hardwood species, Juglans mandshurica, Zelkova serrata, Fraxinus rhynchophylla, Betula schmidtii, Paulownia coreana, or Quercus spp. (Quercus aliena; Q, variabilis; Q, dentata; Q, acutissima; Q, mongolica; Q, serrata) were used. As softwood species, Pinus densiflora and Pinus koraiensis were used. Investigation of the wood species is important part because the same species is required as a principle when reparing cultural heritage. In this study, the anatomical images of the wood species were investigated for some samples which were taken from the same species that has been stored in the wood specimen room of the National Institute of Forest Science, instead of the actual wood material used. It was possible to find out the wood species of each member in the wooden cultural heritage buildings by reviewing the Yeonggeon-Uigwes in the late Joseon Dynasty, and the anatomical images of the wood species required for determining the wood species in the repair or restoration of the buildings.

Ji-yeol Kim , Byung-ro Kim

DOI:10.5658/WOOD.2021.49.5.471 JANT Vol.49(No.5) 471-481, 2021

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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.

Su-young Jung , Ree-keun Kong , Kwang-soo Lee , Hee-seop Byeon

DOI:10.5658/WOOD.2021.49.5.482 JANT Vol.49(No.5) 482-490, 2021

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This research was conducted to analyze the sound absorption effect of air-dried leaves from two evergreen tree species found in Korea's warm-temperate and subtropical regions. As eco-friendly sound absorption materials, Dendropanax morbiferusa, and Fatsia japonica leaves were prepared in three specimen units sizes 0 .5 × 0 .5㎠, 1 .0 × 1 .0㎠, and 2 .0 × 2 .0 ㎠, and each of them was formed at a thickness of 1.00 cm, 1.75 cm, and 2.50 cm. The measured sound absorption coefficients (SAC) for 18 conditions were comparatively analyzed in this study. The SAC of both tree species was significantly improved by increasing the dried leaf layer thickness. These results showed a more consistent and distinct trend for both tree species under the condition of 0.5 ㎠ in dried leaf size compared to other leaf specimen sizes. However, as the thickness increased, the difference in sound absorption effect according to the leaf size tends to decrease overall. In the case of D. morbiferus, there was no significant difference in SAC based on leaf size under the condition of 2.5 cm thickness (p < 0.05). The highest mean SAC was found in a 2.5 cm thick condition with a leaf size of 0.5 × 0.5㎠, 0.549 for D. morbiferusa, and 0.594 for F. japonica, respectively.

Taufik Fathurahman , P. H. Gunawan , Esa Prakasa , Junji Sugiyama

DOI:10.5658/WOOD.2021.49.5.491 JANT Vol.49(No.5) 491-503, 2021

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Wood identification is regularly performed by observing the wood anatomy, such as colour, texture, fibre direction, and other characteristics. The manual process, however, could be time consuming, especially when identification work is required at high quantity. Considering this condition, a convolutional neural networks (CNN)-based program is applied to improve the image classification results. The research focuses on the algorithm accuracy and efficiency in dealing with the dataset limitations. For this, it is proposed to do the sample selection process or only take a small portion of the existing image. Still, it can be expected to represent the overall picture to maintain and improve the generalisation capabilities of the CNN method in the classification stages. The experiments yielded an incredible F1 score average up to 93.4% for medium sample area sizes (200 × 200 pixels) on each CNN architecture (VGG16, ResNet50, MobileNet, DenseNet121, and Xception based). Whereas DenseNet121-based architecture was found to be the best architecture in maintaining the generalisation of its model for each sample area size (100, 200, and 300 pixels). The experimental results showed that the proposed algorithm can be an accurate and reliable solution.

Do-min Gong , Moon-gi Shin , Soo-hyun Lee , Hee-seop Byeon , Han-min Park

DOI:10.5658/WOOD.2021.49.5.504 JANT Vol.49(No.5) 504-513, 2021

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In this study, cross-laminated wood panels were manufactured with four softwoods and three hardwoods with the goal of efficiently predicting the static strength performance using dynamic modulus of elasticity (MOE) and simultaneously revealing the dynamic performance of cross-laminated wood panels. The effect of the density of the species on the dynamic MOE of the laminated wood panels was investigated. Moreover, the static bending strength performance was predicted nondestructively through the correlation regression between the dynamic MOE and static bending strength performance. For the dynamic MOE, the parallel- and cross-laminated wood panels composed of oriental oak showed the highest value, whereas the laminated wood panels composed of Japanese cedar showed the lowest value. In all types of parallel- and cross-laminated wood panels, the density dependence was confirmed, and the extent of the density dependence was found to be greater in the P⊥ and C⊥ types with perpendicular-direction laminae in the faces than in the P∥ and C∥ types with longitudinal-direction laminae in the faces. Our findings confirmed that a high correlation exists at a significance level of 1% between the dynamic modulus and static bending modulus or bending strength in all types of laminated wood panels, and that the static bending strength performance can be predicted through the dynamic MOE.

Ik-gyun Im , Gyu-seong Han

DOI:10.5658/WOOD.2021.49.5.514 JANT Vol.49(No.5) 514-534, 2021

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To estimate the territorial size of Reticulitermes speratus, a species of subterranean termites that damages wooden structures in Korea, appropriate dye markers were selected and the diffusion tendency was analyzed. According to the results of the sensitivity assessment using sawdust diet, increase in dye concentration reduced the amount of feed consumption but the dyeing becomes more intense. Except for the Neutral Red 0.5% group, all other concentration groups, including the control group, showed a survival rate of > 85% until week 4. For both, Nile Blue A and Neutral Red dye markers, all concentration conditions > 0.2%, except for the 0.1% concentration, were maintained for 11 weeks, and no sign of transfer effect was found except when the termites were fed with the dye markers. Therefore, it appears that 0.2% of Nile Blue A and Neutral Red is the optimal concentration for monitoring the R. speratus colonies. Additionally, we prepared an indoor 40 m long foraging arena consisting of a colony of 25,000 termites and released individuals stained with 0.2% of Nile Blue A and Neutral Red at both ends to assess the diffusion trends over time. The results showed that it took approximately 7 days for each dyed individual to gradually cover the 40 m distance and mix with each other. These findings reveal that when mark-release-recapture monitoring is conducted on the R. speratus colonies damaging wooden structures, the extent of the colony’s activity area could be measured and different colonies could be distinguished from each other.

한국목재공학회

DOI: JANT Vol.49(No.5) 535-539, 2021

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한국목재공학회

DOI: JANT Vol.49(No.5) 540-540, 2021

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한국목재공학회

DOI: JANT Vol.49(No.5) 541-541, 2021

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