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Durability of surface preserved wood particle boards submitted to atmospherical influence
1995 - IRG/WP 95-40039
The worldwide problem of the continuously growing deficit of high quality natural wood material has caused the attempts of many research workers to find effective composites such as wood particle boards (WPBs) for replacing the massive wood for constructive purposes, depending on where the boards are exploited - in the open or under a shed, they are submitted to various climatic factors such as heating, drying, moistening, frosting, irradiation, that's why for reaching high atmospheric resistance, it is very important, a durable protection of the WPBs with suitable coatings against the atmospheric influence to be ensured.
L Valcheva


Specific gravity and moisture content of particleboards treated with various chemicals
2005 - IRG/WP 05-40310
The aim of the study was to investigated the effects of particleboard treated with various chemical substances on specific gravity and moisture content The wood raw material used in the experiments were the mixture of coniferous wood [70%, Pinus brutia Ten., Pinus nigra Arn (Lamb.), Cedrus libani Ait.] and black poplar (30%, Populus nigra L.). In this mixture, barks have been accepted up to 5 percent. The used chemicals were in the concentrations of 10-8 % urea-formaldehyde, 10 % ammonium clorure, 10 % rosin, 20 % alkyd resin, 5 % boric acid, 7 % ammonium sulfate, 10 % tanalith-CBC, 5 % borax, 1.76 % immersol-WR 2000, 2.5 / 2.5 % boric acid/borax, 5 / 2.5 / 2.5 % tanalith-CBC/boric acid/borax. According to the result of this study; for all of the particleboards, the density and the moisture content increased with increasing the chemical agents ratio used.
Ü C Yildiz, A A Var, H Kalaycioglu, S Yildiz


Copper-resistant fungi on pressure impregnated wood in Denmark
1994 - IRG/WP 94-10078
The occurence of Amorphotheca resinae Parbery and its asexual stage Cladosporium resinae (Lindau) de Vries on CCA and CCB treated wood has previously been shown. In the autumn 1993 some other blue stain fungi were found on CCP and CCB treated pine timber, such as Ophiostoma minus (Hedgc.) H. and P. Sydow, Ophiostoma pilifera (Fr.) H. and P. Sydow and Ophiostona piceae (Munch) H. and P. Sydow. The absense of arsenic from newly impregnated wood may create improved growth potential for species not previously found on pressure impregnated timber, such as the above-mentioned.
J Bech-Andersen, S A Elborne


Wooden windows, avoidance of damage via constructional measures
1990 - IRG/WP 3591
Increasing awareness of the environment reinforces the trend to use wood as a building material for windows in modern building constructions. Wood is a natural building and construction material. Under certain circumstances such as persistent humidity exceeding 30%, wood is rapidly degraded by decay fungi into CO2 and inorganic salts. The cost caused by damage (e.g. replacement of windows) represents a considerable burden on the economy. Damages on wooden windows can not only be reduced to wood decay fungi acting destructive. Conventional brush- and diptreatment provide only superficial marginal protection. Constructive wood protection (integral solution) taking into account the static and physical properties of the building material wood is of central importance. The film demonstrates the most important reasons for damage and their consequences occuring during planing, constructing and during incorporation of windows into the building. Directions and suggestions for a solution of the problems are given. Suitable isothermic incorporation of the window into the building has significant importance. Formation of condensate, also due to lapse in housekeeping (e.g. lack of ventilation) may be avoided to a far extent. Also damage and reasons for damage, resulting from misconstruction in the area of the glass seam (e.g. sealents that harden) and transom and casement frame areas (e.g. lacking of end caps on the anti-rain strips) are demonstrated in the present film.
R Gründlinger, K Messner


Termite-tunnels formation on the surface of termite-resistant wood species in field sites
2001 - IRG/WP 01-10400
In this report, termite-tunnels formation by the subterranean termite, Coptotermes formosanus Shiraki on the surface of termite-resistant wood species, namely, Hinoki (Chamaecyparis abtsu), Yoshino Hinoki (Chamaecyparis abtsu), Miyazaki Hinoki (Chamaecyparis abtsu), Hiba (Chamaecyparis abtsu) and Japanese cedar (Cryptomeria japonica) was conducted in field sites. Westernhemlock (Tsuga heterophylla), Douglas- fir (Pseudotsuga taxifolia) and Ryukyu pine (Pinus luchuensis) were used as the control. 62 The termite-resistant woods species were classified either as heartwood timber (H) or sapwood timber with a heartwood center (S) and also classified based on their prefecture of origin. Otherwise, the termite- resistant wood species for the termite test were examined in using the forms on the surface of all the termite-resistant wood species by the subterranean termite, Coptotermes formosanus Shiraki. It was found that even for termite-resistant wood species treatment with preservative chemicals is required.
Y Kadekaru, K Kinjo, S Yaga


Preservation of wood-based panels against fungi and insects and and testing its efficiency
1976 - IRG/WP 270
Wood-based panel products which are made of susceptible wood species may be destroyed by fungi under wet conditions and by termites. The glues do not provide sufficient protection unless very high concentrations are applied. Particle boards and fibre boards are not susceptible to beetle infestation, although some species may attack plywood. Various types of preservatives provide sufficient protection of panel products. These are boron, fluoride, copper, and chromium compounds in the category of water-soluble salts and various organic compounds, including contact insecticides, in the category of nonwater-soluble substances. Their application is influenced by their compatibility with the glue and by the different methods of treatment. For the production of fibreboards oil-borne preservatives are preferred. With regard to particle boards and plywood it is recommended to apply the required preservative loadings prior to the pressing operation, to mix them with the glue or to impregnate the particles or plies and with regard to fibreboards to spray the pressed and cooled down panels with the preservative. The fungus cellar test is the most suitable method for testing the efficiency of a chemical treatment of panel products against fungal attack. With regard to beetle species European standard methods of test are available. There are also laboratory and field methods for evaluating the resistance against termites. Treatment standards are controlled by chemical methods of analysis.
G Becker, M Gersonde


Evaluation of the biocide diffusion from treated wood in indoor air. Bibliographic study
1990 - IRG/WP 3584
Within the frame of the risk assessment of the wood preservation products for the Health, the treated wood risk particularly when it is installed in dwellings becomes most important. The European directive "Building materials" (89/106/CEE) mentions the basic requirements with the buildings must comply. Annexe l states in particular that "the building must be conceived and built in order not to become a threat to the Hygiene or the health of the inhabitants. Thus, the treated wood installed in dwellings is concerned. Due to the lack of the official standardized methods, it has appeared interesting to study through literature: -- the well-known methods concerning Formaldehyde diffusion from glue of particle boards, -- the existing works on biocides diffusion from treated wood, -- the parameter entering in the evaluation of quantities diffused in the air, -- the assessment of actual results. This study concludes that the evaluation of biocides diffusion in the indoor air is made by the following process: -- a definition of the experimental protocols adapted for the claims, -- an estimation of the concentrations in the indoor air, from the experimental results, -- an assessment of the human health risk. Some of the existing works already give a better understanding of the factors and parameters which must be taken account. They will make easier the approach of the various experts who will have to cooperate to set up the standard.
A Pichard


The suitability of isothiazolone microemulsions as long term wood preservatives
1997 - IRG/WP 97-30150
Microemulsion formulations of 4,5 dichloro-2-n-octyl-4-isothiazolin-3-one were investigated to determine the leaching potential of these formulation types as well as their efficacy against decay fungi. These patented low leaching formulations exhibited good anti fungal efficacy in standard tests combined with minimal leaching of the active ingredient from the wood. The data suggests that the excellent long term efficacy ( > 10 yrs) recorded in field tests on solvent borne formulations can be repeated with these emulsion formulations. Active ingredient analysis show an excellent penetration and macrodistribution throughout the samples. Preliminary studies using various instrumental analytical techniques on active ingredient microdistribution at the cellular level show an even distribution throughout the cell wall layers. The data indicates that these microemulsion formulations are an excellent vehicle / carrier for solubilization of a water insoluble biocide, its transport and homogenous distribution into the wood without adversely effecting its permanence or efficacy in the wood during long term service.
B M Hegarty, Bing Yu, L E Leightley


Gaseous boron treatments of wood and wood products
1992 - IRG/WP 92-3691
Treatment of wood and wood products by gaseous organoborates has now been under study for about 5 years. This technique has potential for boron treatment of a wide range of substrates from solid wood through to wood composite materials such as particleboard or wet and dry formed fibreboards. The vapour treatment technique is proving to be very flexible in that it can be adapted to integrate into a wide range of process operations and can accommodate special loading requirements. This paper updates the present research in this area and describes treatment of different wood species and wood composite products. We will also anticipate where some of these developments may lead.
A J Bergervoet, R Burton, K Nasheri, D R Page, P Vinden


A field test on susceptibility of wood-based board materials to moulds
1989 - IRG/WP 3545
A field test on susceptibility of wood-based board materials to mould growth was carried out under practical, but severe, service-conditions. A total of 19 commercially available composite boards were investigated. It was found that all board materials tested were not completely immune to mould attack. Test results revealed that among the three main categories of wood-based boards involved, particleboards were the most susceptible, followed by fiberboards. Plywoods were less susceptible to mould growth. The test also showed that among various types of board materials, the asphalted fiberboard, the particleboards made from birch wood shavings, and wood-industry residues were the most vulnerable to mould growth.
Qiao Wang, B Henningsson


Bi-oleothermal treatment of wood at atmospheric pressure: resistance to fungi and insects, resistance to weathering and reaction to fire results
2008 - IRG/WP 08-40418
Bi-oleothermal process is a simple treatment which has been developped by CIRAD in cooperation with FCBA. It allows a deep impregnation of wood with hydrophobic products using cheap facilities. The process includes two steps at atmospheric pressure. The first one is a dipping of wood samples in a hot oil bath (between 110 °C and 200°C) which creates an overpressure inside the wood. The second one is also a dipping in a oil bath but at a lower temperature (20°C to 80°C). In this second bath samples cooling leads to water condensation. A vacuum is created inside the samples and makes the oil to impregnate the wood. In this study, this process has been used to impregnate several wood species with several linseed oils with and without biocides. The resistance to wood destroying fungi has been assessed using a method adapted from EN 113. Results show that the linseed oils lead to an increase in the natural durability. The resistance to termites and to house longhorn beetles has been assessed using EN 117 and EN 47 respectively. Wood treated with biocide-free oil is attacked by termites but afterwards the oil induces the death of the insects. The addition of biocide makes the wood completely protected from termites attacks. EN 47 results show that 93% of mortality amongst the beetles is obtained with the biocide-free oil and 100% with the oil including biocide. The resistance of the treatment to weather has been studied using artificial weathering test according to EN 927-6. Results show that the coating provided by this process constitutes a low performing product compared to conventional stains. However the coatability with a solventborne or a waterborne stain is ensured and leads to good performance after artificial weathering. The influence of the oil treatment on wood exposed to fire was studied on oil treated samples and on samples which were fireproofed and then oil treated. EN ISO 11925-2 tests show the oil treated samples do not pass the test and have a fire classification of F. However samples that have been fireproofed and then impregnated with the linseed oil pass the test and a fire classification of E is obtained. These results were completed with EN 13823 tests. Samples that were fireproofed then oil treated fulfill the C fire classificiation requirements.
L Podgorski, I Le Bayon, I Paulmier, J-D Lanvin, V Georges, D Grenier, H Baillères, J-M Méot


Prevelence of termite infestation and wood preferences in Pakistan
2009 - IRG/WP 09-10695
In order to know about prevalence of termite infestation in Pakistan, A study was carried out to know the intensity of infestation of different species of termites to different types of woods used in buildings as well as in the forests. Heterotermes indicola was the most notorious species of termite present in buildings, grounds throughout the year while Odontotermes obesus was most common in forests. Of the different kinds of woods used in buildings, Sagwan was reported to be highly resistant in buildings. As far as public perception of termites is concerned, only 2% of the people have the knowledge about termite and its proper treatment. In the second part of study, 10 heartwoods of local timbers used in Pakistan were evaluated for their ability to resist termite damage by Heterotermes indicola. Woods were evaluated for forced feeding and not forced feeding bioassays in the laboratory as well in the field for 4- weeks. Tested woods were evaluated for Mean visual ratings, Mean wood mass loss and Mean % mass loss. At the end of experiment, in the field for H. indicola, the wood specimens were arranged in the following descending order of preference Ficus religiosa(FR)< Albizzia lebbeck (AL) < Eucalyptus citriodora(EC) < Heterophragma adenophyllum (HA) < Terminalia arjuna (TA) < Melia azedarach ( MA) < Alstonia scholaris (AS) < Abies pindrow (AP) < Pinus wallichiana (PW) < Erythrina suberosa (ES). In laboratory experiments, both by choice and No choice feeding, the woods were arranged the following order of preference Heterophragma adenophyllum (HA)< Ficus religiosa(FR)< Terminalia arjuna (TA)< Albizzia lebbeck(AL) < Pinus wallichiana (PW) < Alstonia scholaris (AS)< Erythrina suberosa (ES)< Eucalyptus citriodora (EC) < Abies pindrow (AP) < Melia azedarach ( MA).
F Manzoor, S Asma Malik


Wood characterization of Tetraclinas articulata and evaluation of its resistance against lignilolytic fungi
2009 - IRG/WP 09-10697
Coniferous trees of the Tetraclinis articulata known under the Common name thuja from Berberie, is an endemic species from North Africa. The solid wood is much appreciated for its natural beauty and homogeneity and its quality for marquetry and furniture. The aim is to improve Tetraclinis articulate uses. At present, its wood is widely underestimated and sub-used compared to its announced qualities. Previous studies have shown that the Cupressaceous, to which the thuja belongs, possesses extractable compounds called tropolones considered as being responsible for their natural durability. A first objective is to analyse the inherent characteristics of Tetraclinis articulatasolid, a solid wood originated from Morocco, based on its physical and mechanical properties because there is little scientific data in the literature related to the quality of this species of wood. A second one is to assess the anti fungus potentials of thuja sawdust or woodchip recovered at the end of processing the timber. Indeed, the extraction of tropolones can be expensive and unprofitable, it seems therefore interesting to test the anti fungal activities and consider the possibility of incorporating them into particle board and test their durability. We have performed physical and mechanical tests and conducted biological degradation tests. Microbial resistance properties have been investigated to show any possible decay zones in the samples. Preliminary results of the biocides activities in sawdust show that rates from 1 to 2 % of sawdust, incorporated in the culture medium, limit the development of degradation agents as Coriolus Versicolor. In this context, the use of sawdust in an industrial scale in Morocco would be an environmental challenge and an answer to the challenges required, among others, by evaluation of local biomass and the reduction of the use of organic and mineral biocides.
F El Bouhtoury-Charrier, A Hakam, A Famiri, M Ziani, B Charrier


Gene expression of selected decay enzymes produced during biodeterioration of three wood types
2009 - IRG/WP 09-10702
Comparative studies were conducted on the expression of several decay enzyme genes during the decay of pine, cedar, and ACQ treated pine over 10 months. Measurements of MOE, decay rating, and moisture control were monitored for physical properties. Identification of decay fungi and the detection of decay enzymes were carried out before gene expression levels were measured. The MOE of wood stakes decreased more in pine than in cedar and ACQ treated pine, indicating a greater loss of strength. Visual decay rating data paralleled MOE data at each sampling time. Moisture contents of all three wood types in each container varied between 40% and 100% over the 10 months. Basidiomycetes were found on all samples as determined by PCR amplification of the basidiomycete 18s rRNA gene after 4 months. For identification of decay fungi at 4 months, PCR products of basidiomycete 18s rRNA gene were cloned and sequenced. Four species of basidiomycetes on cedar, six on ACQ treated pine, and twelve on pine were identified. The white rot fungus, Phlebia radiata was identified on all wood stakes. P. radiata species specific primers were then designed to track the expression of three decay enzyme genes: lignin peroxidase (Lip), manganese peroxidase (Mnp), and laccase (Lcc) on wood samples. Gene expression data as measured by Real-time PCR indicated that the Mnp expression level on pine at 4 months was very similar to the expression level on ACQ-pine but was not detected on cedar. The Lcc expression level on pine samples at 6 months was 30% less than the expression level on ACQ-treated pine while no Lcc was detected on cedar. The results clearly show that the naturally durable properties of cedar reduce the wood decay community and its activities in comparison to untreated pine and ACQ-treated pine. P.radiata attempted to decay the ACQ-treated wood by producing a large amount of Lcc than was produced on pine but the MOE data showed this attack was not successful. Thus, it appears ACQ-treated wood does not stop the production of the decay enzymes but does inhibit the effectiveness of the enzymes. Results from the study indicate that different resistant woods have different effects on the microbial communities and its enzymatic activities during decay.
Young-Min Kang, L Prewitt, S Diehl


Mold-resistance Effect of Bamboo Wood Treated with CCC-organic Complexes
2009 - IRG/WP 09-30514
Mold resistant effect of CCA, ACQ, CuAz, CCC and the compound of CCC and propiconazole were researched on bamboo wood of Phyllostachys pubescens were reported in this paper. Results showed that all of the test fungicides could protect bamboo wood better from Penicillam citrinum than from Trichoderma viride and Aspergillus niger. The complex of CCC and propiconazole had the best resisting effect on all of the test mold fungi. ACQ had better resisting effect on Penicillam citrinum, but not so effective on Trichoderma viride and Aspergillus niger, especially on Aspergillus niger. CuAz had better effect only on Penicillam citrinum. CCA and CCC had better resisting effect on Penicillam citrinum only at higher retentions, but had poor effect on the other two test fungi.
Sun Fangli, Yang Le, Chen Anliang, Bao Binfu, Li Qiao


Termite Resistant Properties of Wood and Natural Fiber Plastic Composites - AWPA E1 Test Data
2009 - IRG/WP 09-40466
This paper deals with resistance properties of wood plastic composites against Formosan Subterranean Termites (FSTs) based on the AWPA E1 test standard. Sixteen laboratory WPC formulations, four WPC commercial materials, and southern pine (Pinus sp.) wood control were tested for termite mortality, sample weight loss, and sample damage rating. The results show that FSTs did attack WPC products in the laboratory setting. The test was sensitive enough to demonstrate the effect of chemical treatment and type of surface (as-extruded exterior surface versus machined interior surface) on termite resistance. The type of plastics (e.g., HDPE vs PVC, and virgin vs recycled) and fibers (wood, bamboo, and bagasse) was less important, compared to wood fiber loading level and particle size. There was a large difference in damage mode and degree of damage from as-extruded exterior surface and machined interior surface of WPC. Commercial WPC was subjected to more termite attack from the exposed interior surfaces. An effective chemical treatment should prevent termite attack on both types of surfaces for WPC.
Q Wu, T Shupe, J Curole, K Ragon, M Voitier, M Freeman, D Ring


Natural durability of Chilean commercial wood exposed to the action of marine borers
2015 - IRG/WP 15-10849
Results of field experiences of natural durability of ten commercial wood, exposed to the action of Bankia martensi (Stempell) in the South coast of Chile are presented. Tested species were seven types of native wood and three types of exotic ones. Test specimens of standard dimension of 0.02 x 0.045 x 0.23 m with three replications by species were used. The degree of attack was determined according to British norm BS IN 275:1992. Differences in the degree of attack between the wood species and basic properties such as the anatomy, density, hardness and percent extractives were analyzed. After six months of exposure, test specimens were inspected. The response of wood species without protective treatment was in general poor considering the brief lapse of exposition, since all of them were damage, except Quillaja saponaria Mol. Externally, the attack did turn out to be only superficial with orifices of 0.002 to 0.003 m and also abundant organisms were adhered to the surface. The presence of numerous galleries and individuals of mollusc bivalve Bankia martensi (Stempell, 1899), belonging to Teredinidae family, was verified inside the wood specimens.The species that shows minimum indications of attack is Drimis winterii J.R. et G. Forster, with galleries covering in average 0.44% of the surface of the test specimens; Prosopis tamarugo Phil. follows with moderate attack (16.06% of the affected surface); attack severe appeared in: Laurelia philipiana Looser and Pinus radiata D.Don with galleries occupying 29.40 and 32.90% of the area respectively. Failed, with more of a 50% of the surface covered with galleries were: Eucalyptus globulus Labill (52.53%); Pseudotsuga menziesii (52.02%), Nothofagus dombeyi (Mirb.) Blume. (52.58%), Saxegotea conspicua Lindl. (53.82%) and Nothofagus alpina (Poepp. et Endl.) Krasser, the last one reaching 90.95% of its surface covered with galleries
R Carmona C, C Osorio, A Almuna


Termiticidal Effect of Bitumen and Creosote oil Treatments on Selected Nigerian Wood Species
2016 - IRG/WP 16-30689
Termites attack has been a major threat to wood materials in construction. The study investigated the termiticidal effect of bitumen and creosote oil mixture on the resistance of some commonly used indigenous wood species namely: Celtis zenkeri, Terminalia ivorensis, Albizia lebbeck, Cola gigantea and Terminalia superba to termites in Akure, Ondo State, Nigeria. The wood species were obtained from a sawmill in Akure South Local Government Area of Ondo State, Nigeria. The wood samples were separated into five samples each for sap and heartwood using 35 × 35 × 450 mm dimension. Thereafter, they were treated with mixture of bitumen and creosote using hot treatment method. The preservative absorption by the wood samples was determined, coupled with the weight loss of the wood after exposure to termites’ attack in the graveyard for 12 months. Macrotermes sybhylinus was identified as dominating termite species in Akure environ. Weekly visual observations of the stakes were carried out as specified in ASTM D3345-80 Standards for 12 months. The wood samples were withdrawn after 12 months of exposure to termites and weight loss due to attack was estimated. The field test results showed that treatment with bitumen and creosote oil mixture greatly increased the resistance of the five wood species to termites attack. It was also observed that heartwood portion of wood species were resistant to termites attack. The Analysis of variance indicated that there was significant difference between the resistance of treated and untreated samples at 5 % level of significance. From the results obtained, it was evident that bitumen and creosote oil mixture in 70:30 proportions proved very effective as a preservative for protecting wood against termites attack.
Termiticidal Effect of Bitumen and Creosote oil Treatments on Selected Nigerian Wood Species


Black-stain Resistant Acrylic Latexes for Wood Coatings Applications
2017 - IRG/WP 17-40786
Translucent coatings on wood in exterior applications often fail due to photodegradation and colonization by black-stain fungi and require frequent refinishing. This limits competitiveness with alternative materials. In this project, it was hypothesized that an effective dispersion of inorganic nanoparticles will provide a translucent coating with long-term resistance to black-stain fungi. Functionalized silver nanoparticles with a mean particle size of 12 nm were incorporated in acrylic polymer particles by miniemulsion polymerization. This polymerization technique has been selected over the traditional emulsion polymerization to encapsulate inorganic particles into polymer particles and prevent the agglomeration of inorganic nanoparticles. In previous work, it was found that latexes containing silver nanoparticles showed antifungal activity against Epicoccum nigrum, and a mix of Penicillium funiculosum and Aspergillis niger at low silver concentration (0.1% m/m) (Boivin, Ritcey and Landry, 2015). Based on these results, acrylic latexes containing different concentrations of silver nanoparticles were mixed with a commercial acrylic resin. The formulations were applied on ponderosa pine (Pinus ponderosa) sapwood and fungal resistance was evaluated against three species Aureobasidium pullulans, Sclerophoma pityophila and E. nigrum. Latexes with concentrations of silver nanoparticles as low as 0.03% were able to control S. pityophila and E. nigrum, while higher concentrations were needed to control A. pullulans.
G Boivin, A M Ritcey, P I Morris, V Landry


Danish wood preservatives approval system with special focus on assessment of the environmental risks associated with industrial wood preservatives
2001 - IRG/WP 01-50166-01
The following is a description of the procedure used by the Danish Environmental Protection Agency to assess the environmental risks associated with preservatives used in the pressure impregnation of wood. The risk assessment covers issues considered to be of significance for the environment and which are adequately documented so as to allow an assessment. Such issues are persistence and mobility in soils, bioaccumulation and the impact on aquatic and terrestrial organisms. Unless required in special circumstances, the assessment does not apply to birds and mammals as the normal use of preservative treated wood is not expected to involve any noteworthy exposure of these groups. Approval of wood preservatives will be based on a general assessment of the environmental risk associated with the normal use of wood treated with the preservative in a realistic worst case situation. The assessment may address other aspects such as disposal and total life cycle.
J Larsen


Data sheet on wood-boring insects. Apate monachus Fabricius. 2. Position systématique, nomenclature, identification et distribution - Espèces végétales attaquée
1981 - IRG/WP 1105
R L A Damoiseau


Confocal laser scanning microscopy of a novel decay in preservative treated radiata pine in wet acidic soils
1997 - IRG/WP 97-10215
Light microscopy of radiata pine (Pinus radiata D. Don) field test stakes (20x20x500mm3) exposed in wet acidic (pH 3-4) soil for 12 - 24 months showed predominance of an unusual type of decay characte-rised by tunnelling attack of wood cell walls. After two years decay was moderate to severe in wood treated to ground contact CCA specifications and also equivalent retentions of creosote, and a number of new generation preservatives. Relative to other New Zealand temperate test sites and also an Australian tropical site, the New Zealand acidic soil test site was very aggressive. Correlative scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to elucidate the micromorphology of this attack. Tunnels of diameter 0.2-5 µm were present throughout all layers of the cell wall, and their orientation was not related to cellulose microfibril orientation. They also showed no preference for particular cell wall layers, indicating a lignin degrading capability. CLSM images showed that living, connecting fungal hyphae were present in the cell lumina and tunnels. This type of attack was predominant in wood that was highly saturated with water whereas wood that was less moist was predominantly attacked by classical white rot. Ongoing isolation and incubation studies in conjunction with further microscopy should enable identification of the fungal species involved.
R N Wakeling, Ying Xiao, A P Singh


Effect of acetylation on decay resistance of wood against brown-rot, white-rot and soft-rot fungi
1989 - IRG/WP 3540
Effect of acetylation on decay resistance of wood was investigated using wood blocks of Cryptomeria japonica, Pinus densiflora, Albizia falcata and Fagus crenata. Blocks were treated with uncatalyzed acetic anhydride for different lengths of time and exposed to Tyromyces palustris, Serpula lacrymans, Coriolus versicolor and unsterilized soil. The action of OH-radical on acetylated wood was also examined using Fenton&apos;s reagent. The enhancement of decay resistance by acetylation was revealed clearly for all cases of exposures but varying with fungal and wood species used. For a brown-rot fungus Tyromyces palustris, the weight loss reached almost nil in all woods at 20 WPG (weight percent gain) of acetylation, after the striking decrease from 10 to 15 WPG. For a white-rot fungus Coriolus versicolor, it was counted until 12-15 WPG in the perishable hardwoods used, but not in a softwood Cryptomeria japonica, even at 6 WPG. In cases of another brown-rotter Serpula lacrymans and soil burial, effect of acetylation was intermediate between Tyromyces palustris and Coriolus versicolor. Anti-degradation mechanism by acetylation was discussed, from these weight loss - weight gain relationships, and the IR-and 13C-NMR spectral analyses of fungus-exposed wood.
M Takahashi, Y Imamura, M Tanahashi


The IRG..Chanelling information and ideas into the mainstream of wood preservation technology
1985 - IRG/WP 5241
IRG Secretariat


Wood preservation in Poland
2004 - IRG/WP 04-30362
Dynamic growth of market demand for wooden elements and articles, generated in Poland increase of interest in industrial preservation. Today, Poland is a substantial producer and exporter of wood made products. Majority of exported wood - approximately 70% - is scotch pine (Pinus silvestris L.), which, due to its natural durability, requires preservation.
A Kundzewicz


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