한국목재공학회

DOI: JANT Vol.49(No.6) 1-1, 2021

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한국목재공학회

DOI: JANT Vol.49(No.6) 1-1, 2021

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Sei Chang Oh

DOI:10.5658/WOOD.2021.49.6.541 JANT Vol.49(No.6) 541-549, 2021

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This paper reports a method to evaluate the residual strength of insect-damaged radiata pine lumber, such as the screw withdrawal strength as a semi-destructive method and a compression parallel to the grain test to assess the density changes after exposure to outdoor conditions. The screw withdrawal strength test was used as a semi-destructive method to estimate the residual density of decayed lumber. A compression parallel to the grain test was applied to evaluate the residual density. Three variables, such as the screw withdrawal strength, compression parallel to the grain, and residual density, were analyzed statistically to evaluate their relationships. The relationship between the residual density and screw withdrawal strength showed a good correlation, in which the screw withdrawal strength decreased with decreasing density. The other relationship between the residual density and compression parallel to the grain was also positively correlated; the compression parallel to the grain strength decreased with decreasing density. Finally, the correlation between the three variables was statistically significant, and the mutual correlation coefficients showed a strong correlation between the three variables. Hence, these variables are closely correlated. The test results showed that the screw withdrawal strength could be used as a semi-destructive method for an in situ estimation of an existing wood structure. Moreover, the method might approximate the residual density and compression parallel to the grain if supplemented with additional data.

Kwang Hee Lee , Chang Hyun Park , Soo Chul Kim

DOI:10.5658/WOOD.2021.49.6.550 JANT Vol.49(No.6) 550-565, 2021

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This study’s objective was to conduct species identification and tree-ring dating of wooden elements used in Mungyeong Juheulgwan of Joryeong (Gate No. 1). Of the 84 wooden elements evaluated, 76 were confirmed to be hard pines, 5 were soft pines, and 3 belonged to Abies spp. For tree-ring dating, cores of the wooden elements were collected using a drill, and ring-width plots of individual samples were constructed using the TSAP software. The results of performing tree-ring dating for the outermost ring of 59 hard pine wooden elements revealed the following 4 felling dates: summer of 1708-late fall of 1709, summer of 1792-early spring of 1794, late fall of 1838-early spring of 1840 and 1867, and early spring-fall of 1872. These felling dates were found to be consistent with those in the construction and repair records of the Annals of Joseon Dynasty, Juhulgwan Jungsugi, and those engraved on Juhulgwan Walls. It is believed that some of the wooden materials harvested at that time were stored and used since there was a difference of approximately10 years between the repair records and felling dates.

Hyoung-woo Lee , Eun-ju Lee

DOI:10.5658/WOOD.2021.49.6.566 JANT Vol.49(No.6) 566-573, 2021

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We investigated color changes on the outer surfaces of Phyllostachys bambusoides bam-boo by heat treatment under three different temperatures (180℃, 200℃, and 220℃) for three different durations (60 min, 90 min, and 120 min). A method of predicting the bam-boo surface color change after heat treatment was developed to provide valuable information and increase the added value of domestic bamboo products. The three average color parameters L*, a*, and b* decreased, and the overall color changes increased as the severity factor increased. The values of L* × a* × b* were highly related to the severity factor, and the optimal duration time for the desired bamboo surface color with a certain heat-treatment temperature could be estimated.

Hyun Mi Lee , Woo Seok Jeon , Jei Wan Lee

DOI:10.5658/WOOD.2021.49.6.574 JANT Vol.49(No.6) 574-590, 2021

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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 a bout 1 ㎤, 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.

Jeonghee Yun , Hee Chang Shin , Won Joung Hwang , Sae-min Yoon , Yeong-suk Kim

DOI:10.5658/WOOD.2021.49.6.591 JANT Vol.49(No.6) 591-601, 2021

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Recently it is trend to increase wood use as carbon neutral materials, there is recognized to need necessarily durability improvement of wooden building. It is very rare to report existing on the identification of isolates causing discoloration in domestic weathered wooden building used for long period. The objective of this study was identification of fungi that cause discoloration on the exteriors of weathered domestic wooden buildings in the southern part of South Korea. Our findings can be helpful to establish protection technology for weather deterioration of domestic wooden buildings. Wood chip samples presumed to be contaminated with sapstain fungi were collected from the surface of wooden members used in wooden buildings at Jangheung, Jeollanam-do (two locations, #13 and #14), and Jeju Island (two locations, #31 and #33). The growth of microorganisms was confirmed by performing culture tests for the collected samples, and fungi were isolated, purified, and identified. The results indicated that the fungal strains isolated from wooden buildings #13 and #14 at Jangheung, Jeollanam-do, were 99.83% and 100% homologous to Aureobasidium melanogenum, respectively. For wooden building #31 at Jeju Island (two locations), the fungal strain isolated was 100% homologous to A. melanogenum, which is the same species isolated from the wooden buildings at Jangheung. The fungal strain isolated from wooden building #33 (Jeju Island) had 99.83% homology with A. pullulans, which is commonly found in wood degraded by weather or ultraviolet rays. Our findings can be utilized as a basis for establishing protection technology in domestic wooden buildings.

Trisna Priadi , Marini Dwi Lestari , Tekat Dwi Cahyono

DOI:10.5658/WOOD.2021.49.6.602 JANT Vol.49(No.6) 602-615, 2021

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Red jabon wood is a potential fast-growing species for veneer, furniture, and many other wood products, but its durability is very low. The purpose of this study was to investigate the effects of castor bean oil and heating on boron leaching, dimensional stability, and resistance to decay fungi in treated jabon wood. Red jabon wood was preserved with boron solutions containing 5% boron (boric acid, borax, or borax-boric acid). Following that, castor bean oil impregnation and heating were used as posttreatments. Furthermore, all the wood samples were tested in terms of leaching, dimensional stability, and resistance against Schizophyllum commune and Fomitopsis palustris fungi. This study discovered that boron compounds, castor bean oil, and heating treatments influenced the leaching, dimensional stability, and resistance of red jabon wood to decay fungi. The double impregnation of boric acid or borax and castor bean oil, followed by heating at 160℃, significantly reduced water absorption and leaching while increasing the dimensional stability and resistance of red jabon wood against the two tested decay fungi.

Yeonjung Han , Sang-min Lee

DOI:10.5658/WOOD.2021.49.6.616 JANT Vol.49(No.6) 616-642, 2021

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Improving public awareness of wood is essential for achieving the goal of establishing wood culture by expanding the use of wood. This study presents a basic examination of the strategy of revitalizing wood culture and a survey of its current status and requirements. The survey was divided into seven categories: awareness of wood culture; use characteristics of wood culture; preference and demand for wood culture; awareness of sub-fields of wood culture; awareness of the cultural resources of wood; trends of wood utilization; and wood-related living environment. Based on the survey results, the study analyzed four items: awareness of wood and cultural experience; awareness of the cultural resources of wood; wood-related living environment and trends of wood utilization; and preference and demand for wood culture. In this study, the public awareness of wood and cultural experiences, the first of four items, was analyzed using the survey results. Generally, wood and wood culture are viewed as materials and a cultural heritage, respectively. Moreover, wood is ecofriendly. However, no substantial difference was observed between the two perceptions. Forty-five percent of the respondents reported that using wood exerts a positive effect on the body and mind. However, such use also destroys forests. Additionally, the recognition of wood-related workers, such as engineers or skilled workers, was relatively low compared with educators, such as wood education experts. Moreover, less than 50% of the respondents answered that major projects related to wood culture are well-known, whereas 30% participated in wood education, such as woodworking experience, where the majority required hand tools. Furniture, wooden accessories, and wooden buildings were among the objects that individuals intended to make through the wood culture program. Approximately 23% of the respondents were aware about the wood culture experience center, while approximately 50% had visited it. The response rate to woodworking technology was 73%, where the highest response was found for wood education experts. To improve public awareness about wood, the importance of entertainment factors over educational factors should be considered in the experience of individuals. To provide opportunities to experience wood culture for more individuals, developing and actively promoting various contents, including entertainment elements, are necessary.

Yeonjung Han , Sang-min Lee

DOI:10.5658/WOOD.2021.49.6.643 JANT Vol.49(No.6) 643-657, 2021

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In order to establish a strategy for revitalizing wood culture, a survey was conducted on the level of public awareness of wood culture and the experience of wood cultural resources by type. According to the survey, 31.4% of respondents had the images of cultural heritage such as palaces, temples, Hanoks, and cultural assets for wood cultural resources. The main reasons for having no image of wood cultural resources were the ambiguous concept and lack of interest in wood cultural resources. The importance of wood cultural resources classified into seven categories was in the order of cultural heritage, architecture of wood, cultural facilities, cultural festivals, wood products, cultural education, cultural contents. In the survey on the necessity and sufficiency of information on wood cultural resources, 46.7% of respondents needed more information to experience of wood cultural resources, while 64.8% of them had lacked information about wood cultural resources. More than half of the respondents wanted to experience of wood culture within next year, but about 20% of respondents participated in seven kinds of wood cultural resources, except wood products used in daily life. Based on these results, a systematic strategy should be developed to expand the opportunity for the public to experience of wood cultural resources and to promote them to public.

Jun-xian Xu , Yang Liu , Ming-yu Wen , Hee-jun Park , Jia-zhi Zhu , Yu-nan Liu

DOI:10.5658/WOOD.2021.49.6.658 JANT Vol.49(No.6) 658-666, 2021

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A novel flame retardant and antibacterial composite membrane coating for wood surfaces was prepared by adding POSS-based phosphorous nitrogen flame retardant (later referred to as NH₂-POSS) and silver nanoparticles (Ag NPs) to chitosan (CS). The effects of NH₂-POSS content (mass fractions of CS 0%, 0.5%, 1%, 3%, 5%, and 7%) on the structure and properties of the composite membrane coating on wood were investigated. The composite film was prepared by the method of blending and ducting. Contact angle, tensile property and antibacterial effects of the composite film were measured, and infrared spectroscopy was used. The results show that the addition of NH₂-POSS can not only improve the toughness of the membrane, but also the flame retardancy of the membrane, which improves the application of the membrane in wood products. However, with the addition of NH₂-POSS, the transparency of the composite membrane was weakened. The inhibitory effect of the composite membrane on the growth of Escherichia coli was enhanced with the increase in Ag NPs. This research provides a foundation for the application of functional wood.

Yang Liu , Jun-xian Xu , Ming-yu Wen , Hee-jun Park , Jia-zhi Zhu , Yu-nan Liu

DOI:10.5658/WOOD.2021.49.6.667 JANT Vol.49(No.6) 667-678, 2021

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The flame retardancy of plywood should be improved as much as possible while minimizing the impact on the bonding strength of plywood. Six commercial flame retardants and three laboratory synthesized phosphorous nitrogen flame retardants were selected. E₀, E₁ and E₂ grade commercial formaldehyde resins (UF) were applied in this study to evaluate the effect of different flame retardants on the curing time of resin, bonding strength, flame retardant performance, and formaldehyde emission of plywood. The results show that the effect of the addition of different flame retardants on the bonding strength of plywood gradually decreased with the increase of the formaldehyde molar ratio of the resin. The effect of flame retardants on the curing time of UF gradually decreased as the mole ratio of formaldehyde increasing, while the amount of formaldehyde emission varied according to the content of formaldehyde in the flame retardant. Compared with plywood without flame retardant, flame retardant of plywood added with phosphorous nitrogen flame retardant was improved.

한국목재공학회

DOI: JANT Vol.49(No.6) 679-681, 2021

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한국목재공학회

DOI: JANT Vol.49(No.6) 682-682, 2021

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한국목재공학회

DOI: JANT Vol.49(No.6) 683-683, 2021

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