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CCA modifications and their effect on soft rot in hardwoods
1982 - IRG/WP 3201
Decay tests were carried out on wood samples treated with three waterborne compounds all identical in composition but applied in different forms. There were significant differences in the effectiveness of the treatments particularly as regards the control of soft rot.
S M Gray, D J Dickinson


Decay in external joinery in the United Kingdom
1978 - IRG/WP 3116
no abstract available
J G Savory, J K Carey


The effect of treatment method on CCA efficacy in Corsican pine
1992 - IRG/WP 92-3723
As part of a study into the influence of application method on preservative efficacy Corsican pine (Pinus nigra) samples (50 x 50 x 400 mm³) were treated with a CCA formulation using Bethel, Steam/Bethel or Lowry processes. Full penetration of the preservative at a gross level was confirmed using a copper disclosing reagent. The preservative was allowed to fix and then samples were converted into mini-blocks (30 x 10 x 5 mm³) to produce decay test samples from various locations within the larger samples. After leaching, sets of replicate mini-blocks were exposed to the decay fungi Coniophora puteana FPRL 11E, Coriolus versicolor FPRL 28A, and Chaetomium globosum FPRL S70K. Equivalent sets of leached blocks, were analysed using atomic absorption spectrophotometry to determine preservative concentration and balance. The results of this study have been used to assess the effect of preservative application method on CCA efficacy. They also indicate how treatment method affects the distribution of the active elements of the preservative throughout the treated wood.
P R Newman, R J Murphy


Some wood-destroying Basidiomycetes. Volume 1 of a collection of monographs
1981 - IRG/WP 1121
One of the first tasks of the International Research Group on Wood Preservation, when it began its work in 1969, was to compile a series of reports on the common decay fungi which can attack wood. This volume, which contains the first of these reports, has been compiled with the help of mycologists and wood preservation specialists in France, Ghana, the Federal Republic of Germany, the Netherlands, Poland, Sweden and Switzerland, and the United Kingdom. It gives up-to-date information on fifteen common Basidiomycete fungi and indicates the gaps in the world's present knowledge that exist about these.
R Cockcroft


Some observations on miniaturised soil/block tests
1988 - IRG/WP 2317
Results are presented for miniaturised soil/block tests carried out in 120 ml capacity glass jars. The four test fungi (Coniophora puteana, Coriolus versicolor, Gloeophyllum trabeum and Poria placenta) reacted differently to different moisture regimes established by varying the soil moisture content. Acceptable levels of decay were achieved by the three brown rot fungi with soil at 110% whc; however, soil at 150% whc failed to provide a high enough moisture content in the test blocks for decay by the white rot Coriolus versicolor. Overlaying test blocks exposed to Coriolus versicolor with moist sterile vermiculite increased both moisture contents and decay.
J K Carey


Triazoles: Synergism between propiconazole and tebuconazole
1995 - IRG/WP 95-30092
The synergistic action of the two triazoles propiconazole and tebuconazole against wood rotting fungi can clearly be demonstrated by determination of toxic values according to Standard EN 113. The results show that by combining both triazoles a better balanced spectrum of activity can be achieved. The reduction of the toxic values against the white rot fungus Coriolus versicolor (toxic values of the combination remarkable below the values of the individual active ingredients) proves particularly clear the synergistic behaviour of the combination. Additional trials with such combinations (L-joint-tests, lap-joint-tests, soil block tests) are initiated.
H-U Buschhaus, A R Valcke


Laboratory determination of the natural decay resistance of some lesser-utilized timbers from Tanzania against wood decay fungi
2004 - IRG/WP 04-10517
Four lesser known/utilized timber species (sap and heartwoods) from Tanzania, namely Albizia lebbeck, Zanthoxylum gilletii, Faurea saligna and Parinari curatellifolia were exposed to the brown rot fungi (Gloeophyllum trabeum and Coniophora puteana) and the white rot fungus (Coriolus versicolor) to determine their natural decay resistance according to the EN 113 standard procedure. The timbers were also ranked into natural durability classes according to EN 350-1. Albizia lebbeck, Faurea saligna and Parinari curatellifolia timber species (heartwood) were found to be very resistant while Zanthoxylum gilletii was heavily decayed by all the fungi. The durability ratings of the timbers were; Albizia lebbeck (1), Faurea saligna (1), Parinari curatellifolia (1) and Zanthoxylum gillettii (5). It is suggested that the durable timbers, Albizia lebbeck, Faurea saligna and Parinari curatellifolia should be promoted as alternatives to the well known durable timber species in Tanzania such as Tectona grandis, Afzelia quanzensis, Blachylaena hutchinsii and Pterocarpus angolensis which are currently being over-exploited.
P R Gillah, R C Ishengoma, E Julias, S A Amartey, D H Kitojo


Natural decay resistance of some lesser-used tropical hardwoods from Ghana
2002 - IRG/WP 02-10438
Ghana is a tropical African country that is rich in diverse timber species. In order to reduce over-exploitation of the popular timber species and increase the resource base for the wood industry, lesser-used or lesser-known timber species are being promoted locally and for export. To do this successfully, it is essential to determine the physical, mechanical and biological properties of these timber species in order to determine their commercial potential. Natural decay resistance (natural durability) lesser-used tropical hardwoods from Ghana to the wood decay basidiomycetes (Gloeophyllum trabeum, Coniophora puteana and Coriolus versicolor) were determined according to EN 113 (1980). Fagus sylvatica (beech) was used as a reference timber. Based on mean weight losses (%), the timber species were ranked in order of decay resistance to G. trabeum as: Albizia ferruginea Benth. > Petersianthus macrocarpus Macbride > Amphimas pterocarpoides Harms. > Celtis zenkeri Engl. > Albizia zygia Macbride > Anopyxis klaineana Pierre Eng. > Antrocaryon micraster A. Chev.> Celtis mildbraedii Eng; to C. puteana as: Albizia ferruginea > Amphimas pterocarpoides > Petersianthus macrocarpus > Albizia zygia > Anopyxis klaineana > Antrocaryon micraster > Celtis mildbraedii > Celtis zenkeri and to C. versicolor as: Albizia ferruginea > Anopyxis klaineana > Amphimas pterocarpoides > Albizia zygia > Petersianthus macrocarpus > Antrocaryon micraster > Celtis zenkeri > Celtis mildbraedii. Natural durability ratings for the timbers in accordance with EN 350-1 (1993), were: Albizia ferruginea 1 (very durable), Albizia zygia 3 (moderately durable), Amphimas pterocarpoides 3 (moderately durable), Anopyxis klaineana 3 (moderately durable), Petersianthus macrocarpus 4 (slightly durable), Celtis. mildbraedii 5 (not durable), Celtis zenkeri 5 (not durable), and Antrocaryon micraster 5 (not durable).
S A Amartey, F R Hanson


Investigation on different variation factors in the results of mycological test and means to reduce and avoid them
1986 - IRG/WP 2264
In order to clarify the causes of the dispersion observed in the results obtained with mycological tests made in accordance with standard EN-113, different factors assumed to be sources of the variations were studied. These included the moisture content of the test samples during the test, the influence of certain technological properties of the wood, the virulence of the fungus strains, the method by which the test pieces were treated and the effect of the solvent, and behaviour of the wood fungus in contact with the wood preservative. It turns out that certain factors which were supposed to be important are actually secondary (humidity). On the other hand, the virulence of the strains is a major problem and requires a serious examination. Treatment by dipping with a ready-to-use product might avoid errors due to obligatory dilutions. In the end, wood species other than beech and Scots pine be used. However, one must not lose sight of the fact that there is a risk that the toxic values may not always be identical.
D Dirol


Accelerated decay tests to investigate postulated effects of tannins on CCA efficacy in wood
1988 - IRG/WP 3497
Five groups of blocks (10 x 10 x 5 mm³) viz., Pinus patula, Pinus patula impregnated to 4% (w/w) tannin; Eucalyptus grandis, Eucalyptus grandis with natural tannins extracted; and extracted Eucalyptus grandis with tannins returned as above; were prepared. Blocks from each group were then treated to 0, 5, 10 and 15 kg/m³ CCA and challenged in four 15-week decay tests, viz., soil burial, and exposure to monocultures of Chaetomium globosum, Coriolus versicolor and Coniophora puteana. The effect of tannin on CCA efficacy was evaluated by weight losses produced. The antimicrobial effect of tannin in wood not treated with CCA was demonstrated. However, the presence of tannin did not effect CCA efficacy in wood at the preservative retentions tested, since weight losses in CCA treated Pine and Eucalypt, both with and without tannins, were similar throughout all tests.
U L Scherer, A A W Baecker


Preservation of robinia wood (Robinia pseudoacacia L.) stakes by vintners
1982 - IRG/WP 3194
This work discusses decay resistance of robinia wood to fungi Trametes versicolor (L.ex Fr.) Pil. and Coniophora puteana (Schum. ex Fr.) Karst., and also the possibility of influencing its resistance by means of chemical protection. The results showed that natural resistance of robinia wood to these two different agents of wood decay is not the same. It is much less resistant to the fungus Coniophora puteana (Schum. ex Fr.) Karst. than to the fungus Trametes versicolor (L. ex Fr.) Pil. Under certain conditions resistance and, consequently, durability of robinia wood can be increased, if it is impregnated with a chemical using the basis of copper-napthenate.
R Benko


Evaluation of bacteria for biological control of wood decay
1990 - IRG/WP 1426
Laboratory soil-block and agar-block tests were carried out to evaluate the efficacy of bacteria as biological control agents against 5 brown-rot and 3 white-rot fungi. Pretreatment of Southern pine and sweetgum with a bacterial solution prevented decay in agar-block tests. However, the bacteria were generally ineffective in preventing decay in Southern pine, Douglas-fir, sweetgum and yellow poplar in soil-block tests. Wood blocks treated with an autoclaved bacterial solution were not decay resistant by either test method.
R Benko, T L Highley


Quantification of wood decay effects by HPLC analysis
1992 - IRG/WP 92-1576
The present work quantified the effects of the white rot basidiomycetes Coriolus versicolor and Phanaerochaete chrysosporium, and also those of the brown rot fungi Coniophora puteana and Lentinus lepideus, on Pinus patula and Eucalyptus grandis. Wood colonisation was quantified by Kjeldahl nitrogen determinations converted to biomass assays, and degradation was quantified by weight losses produced in the wood. Degraded wood samples were then analysed using high performance liquid chromatography (HPLC) of hydrolysates and their sugar contents were determined to establish whether the glucose of cellulose and xylose of hemicellulose had been utilised by the respective fungi. The extent and nature of sugar utilisation by each fungus in wood was then compared with the biomass and degradation data. Statistical analyses of these comparisons correlated the extents of colonisation, degradation, and the patterns of wood sugars predominantly utilised by each fungus. It was verified that the extent of wood conversion increased with biomass production. Importantly, the result of corresponding glucose and xylose analyses confirmed the brown rot physiological capacity a cellulolytic and hemicellulolytic, whereas that of the white rotters was primarily non-cellulolytic. In contrast, these analyses also showed that the white rotter Phanaerochaete chrysosporium demonstrated some cellulolytic and hemicellulolytic activity. The significance of these findings becomes apparent when colonised wood of apparent soundness is analysed as described here to determine whether or not decay was associated with such colonisation.
V Singh, M Tarin, G D Shelver, A A W Baecker


Influence of CCA and TnBTO on wood decay, under different oxygen levels and various initial moisture content
2001 - IRG/WP 01-10415
Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) were impregnated by TnBTO (tributyl-tin oxide) and CCA (chromated copper arsenate). In wood blocks two levels of moisture content (50% and 100% of saturation point) were used. Three levels of oxygen concentrations (10, 21, and 50%) were chosen. Treated and untreated wood were exposed to three fungi (C. versicolor a white rot, C. puteana, a brown rot, and C. globosum a soft rot). The results showed when TnBTO was used and wood samples exposed to C. versicolor between treated (TnBTO) and untreated specimens was no a big difference in weight losses. Using high moisture content (100%) in wood blocks caused very low weight losses in all treatments to be appeared. When CCA was applied decay by C. puteana was very decreased in Scots pine, therefore, there was a large difference in weight losses between treated and untreated wood. Low oxygen and high moisture content in treated samples caused wood decay by C. puteana did not occur. In the case of C. globosum effect, increasing the moisture content caused that wood decay in all specimens (treated and untreated) to be increased. However, low oxygen concentration in middle moisture content (50% SP) increased decay in beech.
S M Kazemi, R J Murphy, D J Dickinson


Utilization of coconut timber from north Sulawesi, Indonesia. Part 1: Durability
1994 - IRG/WP 94-30044
Coconut timber from non-productive plantations is a byproduct of an agricultural crop and, by the same token, constitutes a renewable resource which may serve as a complement to or, at least in part, as a substitute for traditional timbers in local markets. Its more extensive utilization is expected to contribute to the conservation of tropical rain forests. Export of coconut timber and/or wood products can open up new possibilities for exporting countries to acquire additional supplies of foreign exchange. Earlier attempts of export to industrialized countries were little successful for a number of reasons, primarily inadequate grading and drying before transport, or the lack of experience in processing and chemically treating this very particular raw material. Comprehensive knowledge about technological (physical, mechanical) properties, the durability as well as a reliable preservative treatment are indispensable in order to process and market coconut wood and wood products economically. The objective of this paper is to contribute to the durability of coconut timber.
R-D Peek


A test method to simulate above-ground exposure
1978 - IRG/WP 2112
The simulated above-ground exposure technique described is worthy of consideration as a simple procedure to determine the relative decay resistance of preservative-treated wood exposed to a moderate decay hazard. The method may readily be modified to allow testing of other materials such as plywood by simply enlarging the slots cut in the modified feeder strips. The method by no means completely simulates the conditions that exist in timbers exposed out of ground contact, nor does it simulate the natural process of infection, but it does provide lower toxic thresholds and allow reassessment of relative performance of preservatives under test conditions less severe than those of soil-contact exposures. A fully acceptable test procedure will be available only when a clear understanding is gained of the decay process in timbers and commodities exposed out of ground contact.
J A Butcher


Investigation of extracellular mucilaginous material in some wood decay fungi
1996 - IRG/WP 96-10188
The external morphology of the extracellular mucilagenous material (ECM) produced by Coriolus versicolor and Coniophora puteana during colonization of Scots pine and beech was studies using SEM. Specimens were examined in the frozen hydrated, freeze-dried and critical point dried state. All technics produced artefacts but the ECM was best preserved when examined the frozen hydated state. Critical point drying damaged the ECM extensively but was useful in partly explaining its nature. ECM was found to line much of the lumen and coated aerial fungal mycelium. Some morphological patterns in which the ECM and fungal hyphae were involved are also descibed.
A R Abu, D J Dickinson, R J Murphy


The effect of of sorbitol on the decay of boric acid treated Scots pine
1991 - IRG/WP 1509
The tetra-hydroxy borate ion is known to undergo complexation with polyols of biological importance and probably protects treated timber by this action. The inhibitory effect of boric acid upon fungal growth and dehydrogenases has been shown to be prevented by the addition of certain polyols. This work was extended, with a study of the effects of a polyol on the performance of boric acid in treated wood. It was found that the addition of sorbitol to boric acid treatments of wood, produced a dramatic reduction in the protection against decay, when compared to treatments containing no sorbitol. The results gained in this investigation were found to substantiate the theory of borate ion/polyol complexation being responsible for the protection of boron treated timber.
J D Lloyd, D J Dickinson, R J Murphy


Effect of crude tall oil, linseed oil and rapeseed oil on the growth of the decay fungi
2002 - IRG/WP 02-30299
The influence of crude tall oil, linseed oil and rapeseed oil on the growth of Coniophora puteana, Poria placenta and Coriolus versicolor was studied. The selected test oils were observed to have different effects on the the fungal growth. Crude tall oil inhibited the radial growth of all fungi. Rapeseed oil either accelerated or inhibited the growth of fungi depending on the type of fungus involved. Crude tall oil applied to veneer samples did not produce inhibition zone on the growth medium. This indicates that the inhibitory effect of oil products is not caused by the broad-spectrum toxic mechanisms. In the ENV 807 soil box assessment soft-rot fungi were able to grow over the crude tall oil treated test specimens, regardless the fact that soft-rot decay was significantly prevented.
L Paajanen, A-C Ritschkoff


A biochemical explanation for the observed patterns of fungal decay in timber
1980 - IRG/WP 1111
Experiments designed to compare the degree of localization of the cellulase enzymes of some white, brown and soft rot organisms are described. The site and nature of binding of the enzymes is discussed. The technique is ellution of mycelium grown in liquid culture with a variety: of agents including acetate buffer, carboxymethyl cellulose solution, borate/glycerol buffer and urea. The mycelium was assayed for cellulase activity before and after washing. Eluted protein was also assayed. The effect on retention of cellulases of treatment with a (1,3) ß glucanase was determined. Brown rot organisms showed a far lower retention of cellulases to the mycelium than the soft and white rot organismns. Carboxymethylcellulose solution was found to be only slightly effective as a protein eluent on the white and soft rot organisms indicating low substrate affinity. 8 M urea was found to be an effective protein eluting agent - possibly implying hydrogen bonding between cellulases and the fungus. Borate/glycerol buffer was also shown to be an effective agent for protein elution - however· less so than urea. This agent probably binds to carbohydrates, either glycoprotein enzymes or binding sites on the organism, thius displacing protein. (1,3) ß glucanase markedly decreased the retention of cellulase activity in soft and white rot organisms indicating binding to a (1,3) ß glucan. It is postulated that cellulase retention mechanisms found in soft and white rot organisms and absent from brown rots have a significant role in the production of the characteristic observed patterns of decay of the three types.
N B Green, D J Dickinson, J F Levy


Co-operative studies on determining toxic values against wood-destroying basidiomycetes: Progress report to April 1990
1990 - IRG/WP 2357
This document reports progress on the co-operative study between nine laboratories, set up following the proposals contained in Document IPG/WP/2316 (1988). Results have been received from eight laboratories. Toxic values data have been established successfully for the test fungus Coniophora puteana with soil, malt agar and vermiculite methods and with the test fungi Gloeophyllum trabeum and Poria placenta in the soil method. With Coniophora puteana, there was less variation between the different methods carried out at the same laboratory than with the same method in different laboratories. Various options for further work are put forward for discussion.
J K Carey, A F Bravery


Method to determine the depth of penetration of the biologically active components of wood preservatives
1978 - IRG/WP 2108
A time-saving method for determining the depth of penetration of the biologically active components of wood preservatives is described. The test specimens were obtained by cutting thin slices from the wood either parallel or perpendicular to the treated surface. The slices were then exposed to fungal attack. A good correlation was found between the test results obtained by the modified German Standard method (plane-off test), published by BECKER and STARFINGER (1971).
H-P Sutter


Evaluation of natural durability of solid wood and mixed heartwood-sapwood Cypress (Cupressus sempervirens L.) plywood against Basidiomycete fungi
2008 - IRG/WP 08-10645
The aim of this research was to study the response of mixed plywoods composed of durable heartwood and non-durable sapwood to fungal attack. For this purpose, the species of Cupressus sempervirens (cypress) was chosen for its well-known durable heartwood. The evaluation of durability of plywood panels against fungi was done according to ENV 12038 and the fungi used were Coriolus versicolor (CV) and Coniophora puteana (CP). In order to have the basic data on the wooden element of plywood, the natural durability of cypress sapwood and heartwood in the state of solid wood was also determined against fungi according tothe guidelines of EN 350-1. Plywoods made of pure sapwood and pure heartwood (as controls) allowed a comparison with the mixed ones. 17 different plywoods were laboratory made. The influence of thickness of plies, number of MUF glue line, percentage of heartwood plies integrated to sapwood plies in the mixed plywood, and finally, the way of integration of durable plies in to non-durable plies has been evaluated. In case of solid wood, the heartwood of cypress was found “very durable” against both CV and CP while the sapwood was found “slightly durable”. In the case of plywoods, the evaluation of fungal resistance of pure plywood showed a slight diminution in comparison with the solid wood state. This decrease can be explained by a loss of some extractives molecules during the stage of steaming and peeling. In the mixed plywoods, some of the integrations were found more resistant to the fungal attack. These panels were composed of heartwood layers on the surfaces. It was also found that the criteria of vulnerable surfaces or durable surfaces in plywood is more related to its resistance than the criteria of volume of non durable plies or durable plies that is generally recognized
F Faraji, M F Thévenon, N Lemenager, B Thibaut


Fungal decay resistance and durability of wood products made from borax-impregnated wood and bonded with corn starch and tannin adhesive
2009 - IRG/WP 09-30494
At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol formaldehyde (PF) resins and urea formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply. This paper concerns the decay resistance of wood products bonded with a new, environment-friendly adhesive derived from abundant and renewable cornstarch and tannin.To improve the total resistance of the composite against both Coriolus versicolor and Coniophora puteana rots fungi, borax (di-sodium tetraborate) was added in proportions of 0.5%, 1% and 2% (w/w) to the cornstarch-tannin adhesives. The results showed that increasing the concentration of borax in the adhesive decreased the mechanical properties of the composite. The best way to avoid this problem was to use wood impregnated with borax. Biodegradation studies were conduced on new composites, first without any treatment, followed by borax at 0.5 % aqueous solution treatment. The results show that wood impregnated with borax, in presence of tannin and sodium hydroxide in the adhesive improves the total resistance of the wood composite against both Coriolus versicolor and Coniophora puteana rot fungi.
A Moubarik, A Pizzi, A Allal, F Charrier, B Charrier


Fungal decay resistance and mechanical properties of plywood panels made from maritime pine (Pinus pinaster) and bonded with cornstarch-quebracho tannin-phenol formaldehyde adhesive
2010 - IRG/WP 10-40490
The aim of this work is to demonstrate the performances of cornstarch-quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol-formaldehyde (PF). In order to evaluate the mechanical performances of optimal cornstarch-quebracho tannin-PF, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The biological performance of plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi were evaluated. The performance of these panels is comparable to those of plywood panels commercial PF made. The results showed that plywood panels bonded with cornstarch-quebracho tannin-PF resins (15:5:80, w:w:w) exhibited better mechanical properties than plywood panels commercial PF made. The formaldehyde emission levels obtained from panels bonded with cornstarch-quebracho tannin-PF were lower to those obtained from panels bonded with control PF. Biodegradation studies show that the presence of quebracho tannin in the adhesive improves the total resistance of the plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi.
F Charrier, A Moubarik, A Allal, A Pizzi, B Charrier


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