| Summary: | 碩士 === 國立屏東科技大學 === 木材科學與設計系所 === 102 === Increasing the value and efficacy of utilization for the tree species in Taiwan forest is one of the important issues in the development of sustainable forest management. Therefore, the goal of this study was to investigate the potential of wood tars, obtained from Cryptomeria japonica and Acacia confusa, as wood preservatives in order to increase their utilization and value. Pinus radiata and Acer spp. woods treated with four concentrations (1, 2, 4, and 6%) of C. japonica and A. confusa wood tars were evaluated for leachability, fungal decay resistance, termite resistance, and weathering durability. The leaching test results showed that the chemical retention of wood treated with C. japonica and A. confusa wood tars increased as the concentration increased. Moreover, the chemical retention of wood treated with C. japonica wood tar was higher than those treated with A. confusa wood tar. Results of the fungal decay resistance test of wood (Pinus radiata) treated with 2% C. japonica and A. confusa wood tars after leachability test, exhibited higher decay resistance against brown-rot fungi (G. trabeum and L. sulphureus) than the control. Similarly, lower mass loss was observed on wood (Acer spp.) treated with 1% C. japonica and A. confusa wood tars after leachability test and exposure to white-rot fungus (T. versicolor). According to the termite resistance test, the mass loss of wood treated with 1% C. japonica and A. confusa wood tars after leachability test and exposure to C. formosanus Shiraki was lower than that of the control. In addition, wood of Acer spp. revealed better termite resistance than Pinus radiata. The surface color of treated woods was significantly changed as the concentration of wood tar increased. Moreover, the changes in lightness (L*) and contact angle (°) were gradually decreased, and the respective a* and b* values turned green and blue. The weathering durability test demonstrated that the change in ΔE* values of wood (Pinus radiata) treated with A. confusa wood tar was higher than those treated with C. japonica wood tar after exposure to UVA-340 and UVB-313 for 32 days. However, ΔE* values of wood treated with either wood tar was lower than the control. Furthermore, the change in contact angle (°) tended to decrease as exposure time increased, and the wettability of treated wood exposed to UVB-313 was higher than those exposed to UVA-340. Based on the results of this study, wood (Pinus radiata and Acer spp.) treated with C. japonica and A. confusa wood tars showed excellent fungal decay resistance and termite resistance. Results also revealed that exposure to ultra violet light enhanced the wettability and coating efficiency of wood treated with both wood tars. As a result, it could be suggested that both wood tars have great potential to be developed as wood preservatives in the furture.
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