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A case study of investigating fungi that affect traditional Japanese shake roof with/without copper plates
2013 - IRG/WP 13-10810
A Japanese traditional shake roof is made from split logs. To keep the roof long, copper (Cu) plates are often inserted between the shakes. It has been thought that Cu elements from copper plates would flow out when a shake roof is exposed to rain and inhibit growth of wood rotting fungi. Actually there are some examples where the Cu plates seem to be effective in preventing fungal damage, but on the other hands, there are also cases that significant rot is observed even with insertion of Cu plates. It is important to look at what is going on in such wooden roofs, by describing levels of damage of rot and investigating fungal species, which are involved in the damage. In this study, we investigated a case of shake roof where Cu plate usage seemed to have inhibited wood rot. Wooden parts away from copper plates were decayed with deep cracks, and wooden parts under a copper plate have been preserved well and maintained its original form. Wooden samples, which did not have significant decay visually, were taken from the areas just under copper plates. Also wooden samples, which had severe decay, were taken from areas without copper plates. Filamentous fungi in both types of samples were identified using a cultivation method on malt extract agar (MA) medium and a non-cultural method, the next generation sequencing method. Fungal strains were isolated on MA plates from ethanol-sterilized wooden pieces and non-sterilized pieces respectively, to see fungal species rich on the surface and inside the wooden pieces. Surface sterilization resulted in a big difference from the results obtained with non-sterilized samples. But for now it is unclear whether there are difference in fungal species between the samples taken from the areas adjacent to Cu plates and samples taken from the areas without Cu plates. By using next generation sequencing technology, 12826 (Sample 1, away from copper plates) and 7086 sequences (Sample 2, just under a copper plate) were yielded. ITS DNA sequences from Sample 1 (samples taken from areas without Cu plates) were divided into 3 groups. The main group (11619 sequences) was highly-homologous to species classified as wood rot fungi. The other groups were classified as ascomycetes. On the other hand, ITS DNA sequences from Sample 2 (samples taken from the areas adjacent to Cu plates) were divided into many groups but all the sequences were classified as ascomycetes. Such difference may reflect the states of wood rot, between the Cu plus and Cu minus samples examined in this study.
T Wada, Y Fujiwara, Y Fujii, R Kigawa

Isolation and identification of the fungal flora in treated wood
1976 - IRG/WP 144
J F Levy

Isolation and identification of the fungal flora in treated wood. Revised technique
1977 - IRG/WP 159
At the 8th Annual Meeting in Wildhaus a paper was presented for discussion on the isolation of fungi from treated wood.·Since then work of this nature has been undertaken at Imperial College and as a result a revision of that document has been made and is presented here. The main alterations are: 1) To streamline the isolation procedure 2) Modification of the benomyl agar 3) The inclusion of a standard, low concentration malt medium, for the comparison of all isolates. This was found to be necessary due to the similar appearance of the same organism on different mediar. This isolation procedure thus supersedes the previous one outlined in Document No: IRG/WP/144.
C P Clubbe, J F Levy

The effect of different foundation systems against fungal flora in the crawl space of a new wooden Japanese house
2009 - IRG/WP 09-10700
In order to establish novel preventive measures against damage of wooden houses by decay fungi with less-use or no-use of chemicals, we periodically monitored the fungal flora in the crawl space of a new wooden Japanese house build with recyclable and low-environmental load materials at the Research Institute for Sustainable Humanosphere, Kyoto University. We employed either a layer of concrete or just soil as the foundation system of the crawl space of the model Japanese house. Moisture content of Sugi foundation timbers and temperature & humidity of the crawl space with different foundation systems were measured as well as the sampling of fungi by the following methods: a) from the crawl space atmosphere with a PDA plate, b) from foundation timbers with a soft transparent plastic tape, and c) from small wood blocks laid on a layer of concrete or on soil. Fungi, which were visually estimated to be basidiomycetes, were also identified with DNA-based methods. Then a monoculture decay test was conducted with these fungi. Numbers of fungal colonies grown from the concrete foundation samples were significantly lower than those from the soil foundation samples. Over the year the soil section generally showed higher humidity and moisture content than the concrete section. These findings suggested that the soil strongly influenced the water condition of the crawl space, indicating the higher decay risk in the soil section than in the concrete section. Most of isolated basidiomycetes were white rot fungi with the exception of a brown rot fungus, Fomitopsis pincola. The majority of the white rot fungi were Trametes vesicolor. In order to analyze effect of soil on the fungal flora, all ventilation slits were air-tightly closed with aluminium tape for each crawl space section after all the sampling was completed. This resulted in higher colony forming unites (CFUs), humidity and moisture content of foundation timbers. This study clearly indicated the close relationship between the risk of wood decay and the foundation system in wooden Japanese houses, and the higher decay risk in the soil section than in the concrete section.
A Toyoumi, S Horisawa, T Yoshimura, S Doi,Y Imamura

Effect of Preservative Treatment on Fungal Colonization of Teak, Redwood, and Western Red Cedar
2009 - IRG/WP 09-20404
Fungal flora present in preservative treated samples or non-treated samples from sapwood and heartwood of teak, western red cedar, redwood, and southern yellow pine was assessed after 6 to 18 months of exposure near Hilo, Hawaii. The objectives were to compare fungal composition and diversity between treated and non-treated samples, and to examine the use of molecular techniques for assessing fungal community structure in a ground-proximity-test located in Hilo, Hawaii. Fungi were recovered in culture after 6, 12, or 18 months, yielding 178 unique DNA sequences that represented 85 taxa. Sequence data from the nuclear ribosomal internal transcriber spacer (ITS) region showed the taxa represented 56 ascomycetes, 17 basidiomycetes, 1 zygomycete and 10 unknowns. Basidiomycetes were mainly found in samples treated to the lowest biocide concentrations or non-treated samples, while there were no consistent isolation patterns with ascomycetes. Overall, treatment did not appear to affect community structure. Our results highlight (i) the need for caution in designating taxonomic units (species) based on culture or ITS BLAST matches, (ii) the utility of fungal culturing followed by molecular identification but the limitation of the sampling process, (iii) the remarkably high diversity of fungi colonizing wood in a ground proximity test under these tropical conditions.
Y Cabrera, C Freitag, J J Morrell

A review on prediction methods of wood natural durability
2017 - IRG/WP 17-10892
Natural durability of timber may be defined as “inherent ability of timber to attack by wood destroying organisms (bacteria, fungi, insects, marine borers) without preservative treatment. On the base of biological tests, EN-350-2 standard (Afnor, 1994), describe the classification of wood species according to their natural durability. But these specifications are not adapted in the case of wood species with high variability of natural durability at inter or intra tree level In this case; the variability of natural durability could be detrimental to end-users. Because of standard testing methods are complex and time-consuming, it is important to propose alternative methods to predict natural durability. The focus of this review is to present different methods to predict natural durability based on the presence of chemical extractives, which have long been recognized as key features that impart natural durability of some wood species.
N Amusant, C Flora, J Beauchène, E Houël, C Duplais

Comparison of 1H qNMR and NIR spectroscopic methods to predict heartwood decay resistance in Dicorynia guianensis Amsh
2017 - IRG/WP 17-20601
Dicorynia guianensis is by far the most exploited wood in French Guiana, as it is an abundant tree species associated with good technological properties. However, the decay resistance of D. guianensis wood against lignivorous fungi pathogens is sometimes variable. Therefore, the development of tools to predict the decay resistance of D. guianensis heartwood is relevant in wood science and agroforestry for ensuring a rational use of the resource. Two methods in analytical chemistry are reported herein using near infrared spectroscopy (NIRS) and quantitative nuclear magnetic resonance (qRMN) spectroscopy. Correlations of decay resistance assays with either alkaloid (tryptamine) quantification by qRMN or NIRS data, demonstrate that both predictive methods are prominsing and suitable to predict the decay resistance of D. guianensis heartwood.
C Flora, G Frédéric, M-F Thevenon, Y Estevez, C Duplais, N Amusant