Durability and Fire Performance of Charred Wood Siding (Shou Sugi Ban)

Shou sugi ban, also known as yakisugi, or just sugi ban, is an aesthetic wood surface treatment that involves charring the surface of dimensional lumber, such as exterior cladding. The goal of this research is to examine the effect of shou sugi ban on the flammability and decay resistance of wood. Several species and variants of commercially available sugi ban were tested. The flammability was examined from the heat release rate curves using the oxygen consumption method and cone calorimeter. Durability was examined with a soil block assay for one white-rot fungus and one brown-rot fungus. The testing showed that the shou sugi ban process did not systematically improve the flammability or durability of the siding

Substrate-Specific Differential Gene Expression in the Brown Rot Fungus Fomitopsis pinicola (Retracted and Republished from: “Substrate-Specific Differential Gene Expression and RNA Editing in the Brown Rot Fungus Fomitopsis pinicola ”)

All species of wood-decaying fungi occur on a characteristic range of substrates (host plants), which may be broad or narrow. Understanding the mechanisms that allow fungi to grow on particular substrates is important for both fungal ecology and applied uses of different feedstocks in industrial processes.

Influence of carbon source on wood decay-associated gene expression in sequential hyphal zones of the brown rot fungus Gloeophyllum trabeum

Brown rot fungi show a two-step wood degradation mechanism comprising oxidative radical-based and enzymatic saccharification systems. Recent studies have demonstrated that the brown rot fungus Rhodonia placenta expresses oxidoreductase genes ahead of glycoside hydrolase genes and spatially protects the saccharification enzymes from oxidative damage of the oxidoreductase reactions. This study aimed to assess the generality of the spatial gene regulation of these genes in other brown rot fungi and examine the effects of carbon source on the gene regulation. Gene expression analysis was performed on 14 oxidoreductase and glycoside hydrolase genes in the brown rot fungus Gloeophyllum trabeum, directionally grown on wood, sawdust-agar, and glucose-agar wafers. In G. trabeum, both oxidoreductase and glycoside hydrolase genes were expressed at higher levels in sections behind the wafers. The upregulation of glycoside hydrolase genes was significantly higher in woody substrates than in glucose, whereas the oxidoreductase gene expression was not affected by substrates.

Isolation and identification of the antibacterial compounds in Coptis chinensis for the preservation of wood

Wood is a biomass material that is easily eroded by wood-rotting fungi. Coptis chinensis is a natural green plant, which has an inhibitory effect on most microorganisms. Based on the highly toxic effects of the currently used wood chemical preservatives on humans, animals, and the environment, Coptis chinensis was selected to perform decay resistance experiments of wood in this paper. The active ingredients with bacteriostatic properties in Coptis chinensis were separated and screened via chemical treatment, and their structure was identified via nuclear magnetic resonance spectroscopy. The primary bacteriostatic components in Coptis chinensis were berberine hydrochloride, palmatine, and jatrorrhizine. The bacteriostatic zone experiment with a single component and different compounds for white-rot and brown-rot fungus were tested by the disc agar diffusion method. The bacteriostatic effect of berberine hydrochloride in a single active fraction was better. The three-fraction compound had the best bacteriostatic effect and was equivalent to alkaline copper quaternary. The natural active bacteriostatic fractions in Coptis chinensis had noticeable inhibitory effects on white-rot fungus (Trametes versicolor (L.) Lloyd) and brown-rot fungus (Gloeophyllum trabeum (Pers.) Murrill). The minimum bacteriostatic concentration was 0.01 g/mL. The results showed that Coptis extracts had potential as a wood protectant.

Effects of Decay on the Mechanical Properties of Nailed Joints in Light Wood Frame Structure

For this study, spruce–pine–fir (Picea–Pinus–Abies [SPF]) specification material, oriented strand board (OSB), and domestic twisted nails that were driven vertically and perpendicular-to-grain were selected. Referring to GB/T 13942.1-2009, nailed joints specimens were exposed both to white rot fungus and brown rot fungus for 1 month to 6 months. The monotonous loading test was applied to the specimens based on ASTM D1761-88. The holding power of the nails and weight loss of both OSB and SPF were investigated. Theoretical maximum load of the nailed joints was calculated according to Eurocode5. Results illustrated that the load, stiffness, and energy consumption of the nailed joints showed significant linear decline with the decay time. A linear decline of the ductility coefficient was not obvious, and there was no obvious difference between white rot fungus and brown rot fungus. Effect of decay on the OSB was much greater than the impact on the SPF. The decay grade of the nailed joints was established according to the linear relationship between weight loss and maximum load. Based on Eurocode5, the study calculated the maximum load of the nailed joints and introduced the correction coefficient γ to better predict the maximum load.