Investigation on the properties and control of blue-stained commercial woods

• Main Authors: Chiao-Yu Kuo, 郭巧瑜
• Other Authors: Tsang-Chyi Shiah
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30533640077065430972

碩士 === 國立嘉義大學 === 林產科學暨家具工程學系研究所 === 99 === Wood is a biological material degraded by a variety of organisms. Blue-stain wood shows different discoloration as black, brown and blue colors, this blue stain from fungi. They all reduce the commercial value of the wood. The main objective of this research is to investigation and control of blue-stained commercial woods. Blue-stain is caused by fungi that colonize wood and produce highly colored structures. Ophiostoma quercus with widespread, and numerous reports is the most important staining fungi on conifers and hardwoods. This study is to investigate the decolorization of blue stain by SEM and LM. Hyphae of blue-stain fungi were observed on the discoloration area. The fungi spread radially via the parenchyma cells of the wood rays. Fungal hyphae attack and destroy ray parenchyma cells. FTIR, pH value, 1% NaOH solubility and C/N ratio were performed blue-stained wood and normal wood. Decreases in both the pH value and 1% NaOH solubility were found in wood that has been colonized with O. quercus for 8 weeks. The pH value and 1% NaOH solubility of natural blue-stained wood of Pinus elliottii had the same result with Cunninghamia lanceolata and Liquidambar formosana. In this paper, detailed FT-IR spectroscopic analysis of the chemical changes occurring in blue-stained wood was presented. A comparison has been drawn based on the change of intensity in the specified spectrum of lignin/carbohydrate between inoculated Cunninghamia lanceolata and Liquidambar formosana for an 8-week and a 32-week period, and naturally blue stained Cunninghamia lanceolata, Liquidambar formosana, Pinus elliottii, Picea glauca, Chamaecyparis formosensis and Pinus sp. (Southern Yellow Pine). FTIR spectra show no difference between unstained and blue stained wood. Wood decay will often lead to changes in the proportions of the main components in the remaining wood material, but blue-stain fungi do not alter the structural integrity of the wood. The results showed that blue stain fungi, cause considerable discoloration, but do not cause any significant damage to wood. Cinnamomum osmophloeum leaf oil had great inhibitory effect on the growth of O. quercus (OP20) and Ophiostoma sp. (CK10). MIC (Minimum Inhibition Concentration) of C. osmophloeum against two blue-stain fungi were 500 ppm. The application of 60Co γ-irradiation treatment for the prevention of blue-stain wood. This research carry out the disinfection of C. lanceolata and L. formosana inoculated O. quercus (OP20). We hope to overcome the biological degradation on wood, and then extend its life time. The experiment results are shown, the lowest effective irradiation dosage is 5-10 kGy. Blue stain penetrates into the wood and cannot be removed by surfacing. The bleaching effect of hydrogen peroxide on blue-stained wood are useful. Bleaching alone increased (L*) slightly in the blue-stained samples. The change of wood physical and chemical properties after hydrogen peroxide bleaching treatment need further investigation.