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An Historical Roof Timber System in the Old Town of Berlin-Spandau
2019 - IRG/WP 19-10949
In Europe the “Charter of Venice” was enacted on the 31st of May 1964. It is the international directive for the preservation of historic buildings and monuments. All countries in Europe now involve professional wood scientists and engineers in maintaining and preserving historical buildings. Here we discuss a restoration project involving 17th century roof timbering. This project may be used as a model for the restoration of other wooden historical monuments.
M Luke, W Unger, D Nellessen

International Directory of Members and Sponsors 2018
2019 - IRG/WP 19-60451
IRG Secretariat

Annual Report 2018
2019 - IRG/WP 19-60452
IRG Secretariat

Agenda 2019 Plenary meeting
2019 - IRG/WP 19-60453
IRG Secretariat

The IRG50 Scientific Conference on Wood Protection. Poster abstracts
2019 - IRG/WP 19-60454
IRG Secretariat

Programme. The IRG50 Scientific Conference on Wood Protection
2019 - IRG/WP 19-60455
IRG Secretariat

Budget for 2019 (forecast May 2019)
2019 - IRG/WP 19-60456
IRG Secretariat

Budget for 2020
2019 - IRG/WP 19-60457
IRG Secretariat

IRG Documents 2019
2019 - IRG/WP 19-60467
IRG Secretariat

Biodiversity of wood-decaying fungi in French Guiana sequences of the small subunit (SSU) of ribosomal (r) DNA and the two primer pairs SR6/SR10R and SR7/SR1R
2019 - IRG/WP 19-10936
Fungi from tropical regions are currently under-represented in the classification system. Indeed, difficult access to tropical forests makes it complicated to study fungus species in such environments, unlike in European zones where fungal diversity and taxonomy are much better known. The purposes of this work were: a) to enhance classification by integrating new data that would bring out the importance of certain traits of these fungi, and provide a clearer understanding of how the biodiversity of fungi from the forest ecosystems of French Guiana is organized, particularly those causing wood decay through white rot, brown rot or soft rot; b) to establish a collection of fungal isolates from fruiting bodies collected in French Guiana. This taxonomic study based on sequences of the small subunit (SSU) of ribosomal (r) DNA using the two primer pairs, SR6/SR10R and SR7/SR1R, was carried out on 39 fungus fruiting bodies from Cacao and Régina, in French Guiana. Our protocol enabled extraction, with good repeatability, of fungal DNA from a few mg of pure mycelium. With most of the strains studied we were able to obtain PCR products ranging in size from 376 to 625 base pairs. This study enabled to specify the taxa involved wood decay: 39 species were identified by BlastN. Most of them, in the class of the Basidiomycetes, were the main genera were found, such as Antrodia, Coriolopsis, Fomitopsis, Ganoderma, Poria, Lentinus, Pycnoporus, Auricularia, Gloeophyllum, Trametes, Fomitopsis, Rigidoporus. In addition to the above objectives, the production of pure mycelium from fruiting bodies identified in this study will be used to produce inoculum to test the ability of these fungal species in stimulating oleoresin production in Aquilaria trees from plantation established in French Guyana.
C Zaremski, A Ducousso-Detrez, N Amusant, A Zaremski

Non-stochiometric oxidation and ROS generation promoted by guaiacol lignin structures and lignocelluose surfaces may be a component of brown rot fungal degradation mechanisms
2019 - IRG/WP 19-10937
Model guaiacol compounds representing lignin monomers, as well as DHP-lignin and wood flour of controlled particle size were used to assess iron reduction at the pH of the natural wood cell wall. All compounds functioned as electron donors for ferric iron, with the lignin monomers demonstrating capacity for non-stochiometric reduction of iron with multiple moles of ferric ion reduced per mole of lignin monomer. Iron reduction was enhanced as pH decreased. The results provide a mechanism to explain how lignin may participate as part of a “moving radical front” after initial fragmentation of the lignocellulose cell wall by brown rot fungi. Further, relative to enzymatic action on wood, the data suggest a mechanism to generate electrons that would promote action by fungal enzymes that require an electron donor. The data also demonstrate how hydroxyl radicals would be generated to promote the generation of low levels of formaldehyde from lignin under conditions when lignin surfaces were exposed.
Y Tamarua, M Yoshidaa, L D Eltisb, B Goodell

Difference of wood decay manner between brown-rot species
2019 - IRG/WP 19-10938
Wood blocks (Cryptomeria japonica) which were decayed by a Polyporales white-rot fungus (Trametes versicolor) and brown-rot fungi (Fomitopsis palustris, F. pinicola, and Wolfiporia cocos), respectively, were analyzed by X-ray diffraction and infrared spectroscopic methods followed by multivariate analysis. In the analyses, the differences in the cellulose crystallinities and infrared spectral patterns were observed between Polyporales white-rot and brown-rot fungi. Multivariate analysis of the infrared spectroscopy data also suggested the difference of chemical component between wood blocks decayed by Polyporales white-rot and brown-rot fungi. In addition, when wood blocks decayed by brown-rot fungi belonging to Polyporales (F. palustris), Gloeophyllales (Gloeophyllum trabeum, and Neolentinus, suffrutescens), and Boletales (Coniophora puteana) were analyzed by FT-IR followed by multivariate analysis, the plot pattern of initial decay stage of C. puteana was significantly distinct from those of other brown rot fungi.
R Kondo, Yo Horikawa, S Nakaba, K Ando, M Yoshida

Identifying the fungal community on western redcedar (Thuja plicata) wood in field tests above and in ground contact exposure: preliminary results
2019 - IRG/WP 19-10939
Western redcedar (Thuja plicata) is a high value species in the Canadian forest industry due in large part to the natural durability of its heartwood. Western redcedar heartwood contains extractives that are inhibitory to the growth of many fungi responsible for decay. In order to gain insights into which extractives are important in long term durability, and which fungi are important to decay of western redcedar in service, we conducted a study looking at the fungal community on wood that has been in field tests and monitored for decay for many years. We sampled old growth and second growth western redcedar fence posts that have been in ground contact for 17 years, and deck boards that have been in an above ground test for 14 years. We performed DNA metabarcoding using Illumina sequencing and traditional culturing techniques to characterize the fungal community from samples. Preliminary results from both culture studies and DNA metabarcoding show a predominance of ascomycetes on decks. Basidiomycetes were more frequent on fence posts in the DNA metabarcoding data. The most widespread species detected from decks using DNA metabarcoding was a Hyaloscypha species and from the fence posts was the brown rot species Gloeophyllum sepiarium. The most common species isolated into culture and identified by DNA from the deck samples was the basidiomycete Pachnocybe ferruginea and from the post samples was the zygomycete Mortierella parvispora. Improving our understanding of fungal communities and the role they play in western redcedar decay as well as how they are affected by inhibitory extractives can help in the improvement or development of new wood protection systems, as well as to inform breeding programs aiming to develop seedling stock with enhanced natural durability
A Dale, S Kus, R Stirling

Performance of untreated timbers in above ground decking tests: Preliminary results from an international collaborative trial
2019 - IRG/WP 19-10940
The ability to accurately predict wood decay risks under varying environmental conditions has long been of interest to timber users. Accurate predictions are difficult owing to the myriad of variables associated with the decay process including wood species, wood inhabiting organisms, timber building element design and environmental conditions. Despite these difficulties, decay predictions have been extensively studied, especially in Europe. Predicting decay in non-soil contact exposures represents a less complex process and reasonable predictors of decay risk have been developed using number of days with measurable rainfall and temperature. One drawback of many decay trials is the limited number of environmental conditions examined. The international decking test discussed in this paper was established to create data under a wider range of environmental conditions. Spotted gum along with slash pine heartwood and sapwood were exposed at seven sites in Europe, South-east Asia, Australia and North America. Participants also exposed local species at their test site as well as at the main Australian site. Preliminary results are discussed in relation to site severity as well as the known durability of the various species. The trial is continuing.
L P Francis, J Norton, E Melcher, A H H Wong, J Kok Lai, M Klamer, M J Konkler, J J. Morrell

Decay and water resistance of Siberian and European larch wood
2019 - IRG/WP 19-10941
The occurrence of larch wood is rather frequent in civil engineering. Namely, in building façades, terraces and balcony fences. In Slovenia and other central European countries, the use of the Siberian larch is especially popular. In this research, the durability against decay fungi in laboratory conditions and water exclusion ability of plantation-grown and naturally grown Siberian larch (Larix sibirica) and the European larch (Larix decidua) was investigated. Various tests related to moisture absorption were performed (contact angle, short- and long-term water uptake and water vapour uptake). In addition, the resistance dose DRd, as the product of the critical dose Dcrit and two factors taking into account the wetting ability of wood (kwa) and its inherent durability (kinh) was determined in the laboratory. Results show no significant difference of the wood durability to decay fungi between larch species from a different origin. The higher difference was shown in water performance tests, especially, long-term exposure to the water resulted in a significant difference, which is clearly correlated to the wood density. Combinate effect of wetting ability and inherent durability of tested materials exhibited in resistance dose, where European larch show the highest resistance dose.
B Lesar, D Krzisnik, M Humar

Natural durability of four Tunisian Eucalyptus wood species and their respective compositions in extractives
2019 - IRG/WP 19-10942
In the 50’s, Tunisia government introduced more than 11 Eucalyptus wood species. Eucalyptus species were planted in Tunisia in different arboreta throughout the country for close observation and adaptation to climate and soil. These fast-growing wood species were mainly used as fire wood, for the production of mine wood and to fight against the erosion. These tree species were adapted themselves very well to the Tunisian climate. Now, they tend to become invasive wood species which need to be economically valued. Past study showed that these Tunisian Eucalyptus have great technological properties allowing us to be used as wooden material. However, there is wide variation in heartwood natural durability between eucalypt species. The evaluation of wood durability enables the definition of reliable parameters to predict the service life of wood-based products.This study aimed to evaluate the wood deterioration of four North Tunisian fast-growing eucalypts species (Eucalyptus maidenii, Eucalyptus saligna, Eucalyptus camaldulensis and Eucalyptus gomphocephala) exposed to basidiomycetes (Coniophora puteana and Trametes versicolor) and termites (Reticulitermes flavipes) attacks. Among the four Eucalyptus woods, Eucalyptus gomphocephala presents the highest decay and termite resistance. In addition, it results that the four Eucalyptus wood species are classified as very durable against fungi degradation (Durability class 1) and durable against termite attacks (Visual rating 1), expect for the Eucalyptus saligna which is classified as sensible against termites (Visual rating 3). These natural durability variations according to the wood species have been explained by extractives GC-MS analyses. The natural durability of Eucalyptus seems to be mainly caused by extractives, and a wide range of compounds are involved. But, it appears that it is mostly governed by gallic acid, fatty acid glycerides, fatty acid esters, phenolic compounds, sitosterol, catechin and quercetin.To conclude, Eucalyptus maidenii, Eucalyptus saligna, Eucalyptus camaldulensis and Eucalyptus gomphocephala woods could be used as material sources to improve the economy of the wood sector in Tunisia
S Ben Ayed, M T Elaieb, S Dumarçay, B De Freitas Homen De Faria, M-F Thévenon, P Gerardin, K Candelier

Chemical defense of trees and wood natural durability: from protection to valorization
2019 - IRG/WP 19-10943
Natural durability of wood is defined as “the inherent resistance of wood against various wood-destroying organisms” (European standard EN 350-1). This property is due in particular to heartwood extractives. However, the wood natural durability is included in a wider defense system, and other organs such as bark and roots also host protective compounds. Studying the mechanisms on which global chemical defense relies can give insights into the tree functioning, but also inspire new solutions for scientific and technical innovation. Firstly, we will highlight the link between the role of volatile organic compounds (VOCs) in tree chemical defense and the optimized production of economically valuable products such as essential oils. We will then present previous works performed by our team aiming at understanding the chemical resistance mechanisms of durable woods against fungi, to eventually isolate and identify antifungal compounds that could be used for the treatment of human fungal diseases, in the context of a bio-inspired approach. Lastly, we will show that the use of wood residues obtained from naturally durable trees transformed by the timber industry can be a sustainable strategy to develop innovative products for human well-being or health.
E Houel, D Stien, N Amusant

Determining the natural durability on xylarium samples: mini-block test, wood powder and chemical profiling
2019 - IRG/WP 19-10944
Xylaria, or wood collections, can be considered sleeping beauties in terms of wood technological and biological output. In this study we focus on determining the natural durability of xylarium specimens from the Federal Xylarium in the Royal Museum for Central Africa. The Federal Xylarium contains over 80,000 specimens, covering more than 13,000 species, mainly from Central Africa. These specimens have a random format (disks, book-shapes…) and should be treated with care when sampling for testing, as these specimens are not only limited in size, but also have a significant historical and cultural value. This makes it impossible in most cases to retrieve standard specimen dimensions as required according to CEN/TS 15083-1 (2005). To gain information on the natural durability of these xylarium specimens, two tests were performed: a mini-block test similar to the test described by Bravery (1978) and an indirect assessment using chemical fingerprints. In total 1112 mini-block samples were prepared from 577 xylarium specimens, covering 33 tropical species and complemented with 545 reference specimen, covering 11 species for benchmarking. The natural durability of the wood samples was assessed using the white-rot fungus Trametes versicolor. Beech wood was included as a reference to check whether the fungus was sufficiently virulent. The resulting natural durability classes per species of the mini-block test are similar to those found in common literature. Erythropheum suaveolens and Millettia laurentii appear highly durable, while Pycnanthus angolensis and Terminalia superba performed worst. Chemical fingerprints for the xylarium test specimen were obtained using Direct Analysis in Real Time – Time of Flight Mass Spectrometry (DART TOFMS). Several ions/molecules appear to be correlated with natural durability, showing the potential towards quick screening of the natural durability potential of a certain specimen/species
V Deklerck, L De Ligne, J Van den Bulcke, E Espinoza, H Beeckman, J Van Acker

Coula edulis baill an unknown wood species as an alternative to the main durable wood species used in Gabon
2019 - IRG/WP 19-10945
The Congo Basin hosts an exceptional biodiversity of trees, flora and fauna. However, the immense natural heritage of the forests in this area is increasingly threatened by many anthropogenic factors, due to selective exploitation of certain wood species. In Gabon, whose ecosystem is representative of this area, the forest represents nearly 80% of the national territory. Only a minority of wood species is exploited because of their high market value (Ageos, 2015). The direct consequences of this selective exploitation are the decrease of the disponibility and even the eventual disappearance of certain wood species associated to the fast-growing international tropical timber markets. This is the case for kevazingo, which is classified as an endangered species and therefore prohibited from exploitation. In addition to these main exploited species, several less known species are available in Gabon. This is the case of the Gabonese hazelnut tree (Coula edulis baill), whose wood is used by local populations for its longevity because of its resistance to fungi, insects and more particularly termites. It is used to make forge coal and is used in the construction of huts such as posts and lintels (Moupela C et al, 2010-2013). In this context, it seemed interesting to study more in detail this species, having for the moment been the subject of little scientific investigations. The aim of this study was to investigate the natural durability of Coula edulis and the reasons of this latter one based on wood chemical composition. For this purpose, durability tests were carried out in Petri dishes on native and extracted samples of heartwood towards brown rot (Poria placenta and Coniophora puteana) and white rot (Coriolus versicolor and Pycnoporus sanguineus) fungi showing that unextracted samples presented higher durability to fungi. Fungal growth inhibition tests carried out with different concentrations of extractives confirmed their important fungicidal effects. Percentage of the different wood polymers and chemical composition of wood extractives were evaluated to find correlation between durability and wood chemistry. Results indicated that natural durability of Coula edulis could be explained by several reasons like the high density and hydrophobicity of its wood as well as its high lignin and extractives contents. Chemical analysis performed on extractives by GC-MS indicated the presence of gallic acid, quercetin and tannins.
C S A Bopenga Bopenga, S Dumarçay, P Edou Engonga, P Gerardin

From fungal detoxification systems to wood durability in neotropical forests
2019 - IRG/WP 19-10946
White-rot fungi are able to mineralize all the wood components due in particular to an efficient detoxification system. We hypothesised that components of this detoxification systems, glutathione transferases, could be used as tools to explore the natural durability of neotropical wood species. Analysis of the interactions between six glutathione transferases of Trametes versicolor and extracts of 21 wood species from French Guiana revealed a positive correlation between natural durability of the tested wood species (soil tests) and these interactions (Glutathione Transferase Assay). The obtained data suggest that the developed biochemical test could be used to estimate wood natural durability
T Perrot, G Salzet, N Amusant, J Duchene, E Gelhaye

Green Coloration of Wood in the Forest and Laboratory by Chlorociboria spp. – Applications for Furniture
2019 - IRG/WP 19-10947
Discoloration of wood caused by living saprophytic fungi is commonly found on lumber. These fungi do not destroy the integrity of wood, but the discolorations they cause are often considered undesirable. In Tunbrigde Wells (Great Britain), seldomly found green colored wood, usually considered commercially irrelevant, was valued for use in restoration of wood inlay artwork. The aim of this research was to investigate the distribution of green colored wood in the Biosphere Schorfheide-Chorin, north of Eberswalde, Germany. 15 occurrences were found. The fungus was identified as Chlorociboria aeruginascens. While inoculation of wood with mycelium of the fungus grown on malt agar dishes was not possible, we were successful in transferring the fungus from infested wood to new Alnus glutinosa wood in a field trial. Trials with a pure culture of Chlorociboria aeruginosa completed the research.
S Krause, W Unger, P Heydeck

Study on “Washing” used in Traditional Wooden Building in Japan -Survey in KawaraMachi Area, Gifu Prefecture
2019 - IRG/WP 19-10948
This study is about the actual method of Japanese lattice washing on the traditional buildings of KawaraMachi area, based on interview survey. KawaraMachi area is located on the river side of the Nagaragawa River, so since long years ago it flourished as a center of economic activities, by river transportation. Many wooden buildings influenced by these backgrounds exist in the city. These streets are designated as "Important Cultural Landscapes (Japan)". People in this area wash the Japanese lattice and timber parts of the house facing street with water. This custom keeps a distinctive townscape with yellow-brown wood surface that have dropped old colors. It is highly valued as a valuable historical cultural asset. Therefore, the actual method of “Japanese lattice washing” was investigated. As a result, follows were confirmed. 1. Japanese lattice washing is a custom since at least two or three generations ago from now. 2. Each house hold has handed down the each method of Japanese lattice washing custom.
K Tanaka, H Ishiyama

Effectiveness of Gleditsia triacanthos heartwood extractives as wood protector
2019 - IRG/WP 19-10950
In Uruguay, Gleditsia triacanthos (known as honey locust) is an exotic tree species categorized as invasive; it produces severe ecological impact as it displaces native species, causing changes in the structure of the native forest community. Being extremely difficult to control, it is widely distributed through Uruguay and neighbouring countries. However, one way to mitigate its negative impact is to identify opportunities to use it by revaluating its biological products. This work aims to study the applicability of this species as a source of both wood and non-wood products, transforming it from a problem to a resource. In order to do this, its natural durability was determined, and the extractives of the heartwood (particularly the tannin) were studied. Tannins have a great structural diversity and biochemical characteristics, such as their biocidal activity, making them suitable for wood protection. The extraction of the wood was done by ethanol infusion for 24 hours; once the yield of the extraction was determined, the tannins were quantified and analysed by FTIR. The obtained extract was then taken to a concentration of 5% (w/w), and combined with boric acid (2%) and hexamine (1%). Sapwood samples of Pinus taeda and Eucalyptus grandis were impregnated by vacuum – vacuum with the resulting mixture. The resistance of the treated wood was tested against two decay fungi, Coriolus versicolor and Gloeophyllum trabeum. The results show that Gleditsia triacanthos wood is moderately durable, allowing its use with the appropriate treatment in situations of greater risk of deterioration. The FTIR analysis verified the presence of polyphenols in the heartwood extract, and testing the treated samples proved the effectiveness of the mixture as a wood protector.
C M Ibanez, C Mantero, P Raimonda, X Pintos, E Pereira

Characterization of Pectinases from Brown-rot Fungus Fomitopsis palustris
2019 - IRG/WP 19-10951
Brown-rot fungi occur on softwood used as building materials and cause destructive breakdown of wood structure. Therefore, a more accurate understanding is important from the perspective of wood protection. Previous studies have reported that hyphae of brown-rot fungi go through bordered pits on tracheids when the fungi grow into softwood [Francis W.M.R.Schwarze (2007)], and torus existing in the middle of the bordered pits contains pectin abundantly [D. Maschek et al. (2013)]. However, there is a little information on pectin degrading enzymes from brown-rot fungi. In this study, pectinases from brown-rot fungus Fomitopsis palustris were purified and characterized. Fomitopsis palustris was cultivated on the liquid medium containing 2% pectin, and the culture supernatant after the cultivation was recovered by filtration. Proteins in the supernatant were concentrated with 70% saturated (NH4)2SO4, and a polygalacturonase was purified as one of the pectinases by applying to 4 steps of column chromatography. Enzymatic activity was assayed by using sodium polygalacturonate, the main chain of pectin. Purified polygalacturonase was designated as PG-A, and its properties were analysed. Purified PG-A degraded sodium polygalacturonate acting in an endo-like manner. PG-A was not able to degrade calcium polygalacturonate gel that was prepared by mixing sodium polygalacturonate with calcium chloride in distilled water. Pectin in wood is known to be gelling with calcium ions, therefore, PG-A was suggested to degrade pectin in wood in cooperation with other molecules. We presumed that oxalic acid plays an additional role when PG-A degrades pectin in wood. PG-A was found to be able to degrade calcium polygalacturonate gel in the presence of oxalic acid. Moreover, the thermal stability of PG-A was increased in oxalate buffer at pH 3.0 compared to that in phosphate buffer at pH 7.0, which also indicates the importance of oxalate in pectin degradation by PG-A. In addition to calcium polygalacturonate gel, PG-A was unable to degrade methylesterified pectin, which has a similar structure to pectin in wood. We have partially purified pectinmethylesterase from Fomitopsis palustris, and the investigation of the relationship between PG-A and pectinmethylesterase is now under way.
Y Tanaka, N Konno, T Suzuki, N Habu

Diversity of wood decay fungi isolated from ground-contact wood stakes in Korea
2019 - IRG/WP 19-10952
This study was conducted to investigate wood decay fungi from 5 different ground-contact wood stakes in Korea. A total of 73 basidiomycetes were isolated and identified into 20 genera and 22 species by using molecular method. Among all fungi, only 6 species were brown-rot fungi and the others were white-rot fungi. Pinus densiflora and Quercus variabilis showed high fungal diversity and isolation frequency, but there was a significant difference in diversity between both of them. In addition, dominant species was also different depending on wood species. Wood species was the major source of difference in community of wood decay fungi. Therefore, this information will be useful for wood protection of outdoor facility made by wood.
S-M Yoon, M-J Kim, W-J Hwang, Y-S Choi, D-W Son

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