• Journal of the Korean Wood Science and Technology
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• 제50권2호
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• pp.113-125
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• 2022

This study aimed to explore the biodiversity of chemical compounds found in the bark of Guibourtia tessmannii from Gabon, commonly called Kévazingo, and evaluate their anti-termite activity to determine their potential values as a source of development of anti-termite products that can be valued in the fields of fine chemicals and wood preservation. Extraction of G. tessmannii bark powders was carried out using the cold maceration method with trichloroethylene, acetone, ethanol, and water. Phytochemical screening made it possible to highlight groups of chemical families present in the extracts. Anti-termite activity was tested on the wild termites "Cubitermes sp" of the genus Isoptera. The yield of the extracts were 17.11% for the buttress and 13.42% for the height at 6 m. Phytochemical tests revealed that alkaloids, polyphenols, sterols, tannins, reducing compounds, flavonoids, saponins, and anthraquinones were present in the extracts. Results of anti-termite activity indicated that anti-termite activity varied with the different parts of the bark studied, extraction solvent, and concentration (50/50) and (25/75) of the extracts used. The extracts at 50/50 concentration showed a slightly better anti-termite activity compared to the 25/75 concentration. In addition, the buttress Kévazingo or buttress showed the strongest anti-termite activity for the aqueous extract with a survival rate of 0% after 2 days.

• 한국가구학회지
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• 제12권1호
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• pp.11-20
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• 2001

To investigate weathering and surface characteristics of coating film on lumbers coated with Hwangchil(varnish of Dendropanax morbifera), we carried out to investigate the resistance against discoloration, value of crack and surface characteristics of coating films on seven domestic lumbers and those of four introduced tropical lumbers. There was investigated to evaluate the properties of coating films by the varnish of Dendropanax morbifera. There was insignificant correlations between the hardness and moisture contents of each lumber treated by the varnish. There was no significant correlations between the thickness of coating film and the hardness, either. Although we investigated 11 wood species, we found only three species as resistance wood species against discoloration; Diospysos spp., Abies holophylla and Ulmus davidiana. The crack of coaing films was the largest on Zelkova serrata followed by Juglans sinensis, Cercidiphum japonicum, Tectona grands, Ulmus davidiana, Guibourtia tessmannii, Diospysos spp. and Dalbergia latifolia. However, there was no crack of coating films on the lumbers of Juniperus rigida, Prunus serrulata var. spontanea and Abies holophylla. The crack of coating film showed positive correlations with the thickness of coating film and hardness. The surface characteristics of the coating films evaluated on the basis of $R_{a}$ values indicated the lumbers of Ulmus davidiana($0.14{\;}{\mu}m$), Juniperus rigida($0.1 5{\;}{\mu}m$), Guibourtia tessmannii($0.19{\;}{\mu}m$), Dalvergia latifolia($0.20{\;}{\mu}m$) and Diospysos spp.($0.20{\;}{\mu}m$), Cercidiphum japonicum($0.24{\;}{\mu}m$) as good species while there was insignificant differences between softwoods and hardwoods. Tectona grands, Prunus serrulata var. spontanea and Abies holophylla showed rough surface with $1.53~2.63{\;}{\mu}m$ of $R_a$ values. The four kinds of rough indices($R_a,{\;}R_z,{\;}R_{max}{\;}and{\;}R_q$) showed very low correlations with moisture contents with the correlation coefficients. The $R_a{\;}and{\;}R_{max}$ also showed slight relationship with hardness.

• 한국가구학회지
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• 제28권3호
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• pp.233-247
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• 2017

Woodcraft activities have an inseparable relationship with our daily life, and it is a field that needs to be continued because of the value of education for the growing students. The interest in woodworking from childhood to old age is rapidly expanding nowadays, therefore this study has been done to provide images to those who are engaged in woodcraft business and also those who are interested in this field. If we look at the use of wood in our daily life, We can classify it into Architecture, Civil engineering, Furniture, Musical Instrument, Packaging, Recreational instrument, Exercise instrument, Stationery, Daily commodity, and Industrial use. Among them, We examined kinds of stationery and which type of woods were used. As a result of classifying 101 stationery products in 22 countries, stationery materials using wood can be used for Business cards, Envelope houses, Box houses, Pen holders, Locker plates, Stationery baskets, Book holders, Stamps, Paper knives, Bookmarks, and Photo frames. It was found various wooden stationery are made in USA, Japan, UK, Canada etc. And the most frequently used species are hardwoods such as Walnut (Juglans regia), Maple (Acer spp.), Cherry (Prunus serotina), Birch (Betula spp.), Mahogany (Swietenia macrophylla), Tulip (Liriodendron tulipifera Linnaeus), Bubinga (Guibourtia tessmannii J. Leonard), Wenge (Milletia laurentii De. wild), Cocobolo (Dallbergia cultrata Grah), Zebrawood (Microberlinia brazzavillensis A. Chev.) and Ebony (Diospyros spp.).