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The influence of cement and calcium compounds on the performance of CCA preservatives
1983 - IRG/WP 3221
The influence of cement and calcium compounds on the durability of untreated and CCA treated wood is considered. Calcium compounds were found to reduce the toxicity of a CCA preservative to a soft rot fungus at copper to calcium ratios of 1:1 and 1:10 using a cellulose filter paper technique. Further studies are outlined and some possible mechanisms by which cement and calcium compounds may affect the performance of CCA preservatives are discussed.
R J Murphy


A comparison of soft rot, white rot and brown rot in CCA, CCP, CCF, CCB, TCMTB and benzalkonium chloride treated Pinus radiata IUFRO stakes, after 9-15 years exposure at five test sites in New Zealand
1991 - IRG/WP 1485
The aim of this study was to determine if decay type varies significantly between five field trial test sites of different soil type, aspect and climate in 9-15 year old, replicate CCA, CCF, CCP. CCB, TCMTB and AAC treated IUFRO stakes. A visual on-site assessment of decay type on every test stake was made and observations confirmed by microscopical examination. Regression analyses were used to determine significant differences of percentage frequency of occurrence of each rot type between sites and preservatives. Large differences in percentage frequency of occurrence of rot type were evident between sites. One site was dominated by brown rot (85%) and two were dominated by soft rot (99 and 91%). The fourth site had intermediate proportions of brown rot (40%) and soft rot (71%) but had the second highest occurrence of white rot (32%) (highest = 37%; lowest = 11%). The fifth site was distinct in that a large proportion of stakes (69%) had both well established brown rot and soft rot. Stakes at the other four sites tended to have only one rot type. Some highly significant preservative effects were also found. Possible causes of these differences are discussed in terms of inter-site soil type, climate and other differences.
R N Wakeling


Cytochemical localization of hydrogen peroxide in brown rot fungus Tyromyces palustris by cerium chloride technique
1999 - IRG/WP 99-10299
Cerium chloride (CeCl3) was used to localize H2O2 cytochemically for studying relationship between ultrastructural and functional characteristics of cellulose degradation by brown rot fungi. This technique proved very useful in localizing discrete electron-densereactionproducts at high resolution with minimal nonspecific deposition. The cytochemical localization of extracellular H2O2 by CeCl3 using TEM demonstrated the presence of H2O2 within the fungal hyphae. Furthermore, our results give an indication of the diffusion of extarcellular H2O2 from brown-rot decay fungi into the intact wood cell walls in the early stages of decay.
Yoon Soo Kim, Seung-Gon Wi


Results of co-operative studies on determining toxic values against wood-destroying Basidiomycetes. Preliminary report to Sub-group members
1986 - IRG/WP 2271
A F Bravery, J K Carey


Patent on the use of tannic acid and ferric chloride against marine borers, etc
1982 - IRG/WP 495
R Mitchell, T D Sleeter


The Role of Coformulants in Preventing Bacterial Biotransformation of IPBC
2002 - IRG/WP 02-10436
The inhibitory effects of disodium tetraborate decahydrate and benzalkonium chloride (BAC), two common coformulants of IPBC in antisapstain treatments, on an IPBC-transforming enterobacterial isolate ‘W1’ were determined by their effect on the specific growth rate constant in vitro. The IC50s of IPBC, BAC and borate were found to be 0.46, 0.026 and 5.7 mM respectively. The IC50 of the Arch antistain product AntibluTM Select was 0.024 mM, based on its BAC content. Although their IC50’s were significantly different, it was clear that the vast majority of the bacterial toxicity of the AntibluTM Select was due to its BAC content. The degradation of 0.4 mM IPBC by the bacterium W1, as measured by the accumulation of its degradation product, iodide, in liquid culture, was completely inhibited by BAC concentrations greater than 18 μM, and the toxicity of the spent culture medium to Aspergillus niger, as measured by an antibiotic assay disc assay, was not ameliorated above this concentration. Below 18 μM, the toxicity of the spent broth was significantly reduced, and the accumulation of iodide occurred rapidly. Demonstrating the toxicity of BAC to bacteria, and its consequent inhibition of IPBC degradation in vitro, are indicative of the importance of coformulation in controlling bacteria that might otherwise cause preservative loss, and of their significance in determining the ultimate environmental fate of cobiocides.
S R Cook, D J Dickinson


Wood in concrete. Summary of discussion at IRG 14, Surfers Paradise, Australia
1984 - IRG/WP 3264
The performance of untreated and preservative treated wood when placed in direct contact with concrete was considered in a discussion session at IRG 14. While published reports in this area are scarce, research is in progress internationally and a variety of practices are currently available to minimize any additional hazard posed by contact with concrete. This report summarizes the points raised at the IRG discussion.
R J Murphy


Laboratory study on the effectiveness on photostable pyrethroids formulated with benzalkonium chloride to be used on furniture
1985 - IRG/WP 3346
The first results are presented of a study on the effectiveness of photostable pyrethroids formulated with banezalkonium chloride. Initially the products were submitted to preliminary tests and then the more efficient formulations were tested with a new essay that tries to simulate a dry-wood termite attack on furniture.
A M F Oliveira, A T De Lelis


Collaborative soft rot tests: Results of analyses of soil samples
1976 - IRG/WP 263
C R Levy


The effect of didecyldimethylammonium chloride on growth of different strains of mould fungus Gliocladium roseum
1995 - IRG/WP 95-10105
The tolerance and degrading ability of different strains of Gliocladium roseum towards didecyldimethylammonium chloride (DDAC) were studied. All four of the strains of Gliocladium roseum were tolerant to DDAC and after their growth on amended malt agar, the retention of DDAC in the medium was reduced.
Yu Zheng, J N R Ruddick


Tests on preservation of wood against marine borers
1976 - IRG/WP 417
The Instituto del Legno has carried out for some years a series of trials about the biodeterioration of wood in the sea. The investigations included the settlement and activity of marine borers, the natural durability of indigenous and tropical woods and the preservation of wood for marine use. This paper reports the trials on the effectiveness of some preservatives in protecting wood against marine borer attack. The trials were carried out at Follonica station, where some investigations had shown that untreated pine samples submerged in the sea were totally destroyed by marine borers within 1 year. Follonica station, latitude 42° 55' North and longitude 10° 45' East, is situated on the Tyrrhenian sea. The recorded temperature varies between 12°C (January to March) to 25°C (July to September), salinity between 37 to 38% and pH about 8. The borers observed in wood were: Nototeredo norvagica Spengler, Bankia carinata Gray, Limnoria tripunctata Menzies and Chelura terebrans Philippi.
A Gambetta, E Orlandi


Variation in Canadian bluestain fungi: Tolerance to DDAC and DOT
1999 - IRG/WP 99-10303
Bluestain in Canadian wood products results in significant and unpredictable losses each year. In order to develop rational methods to eliminate or reduce the sapstain problem, a more complete knowledge of the causal organisms must be gained. This includes a knowledge of the variability in tolerance of different fungal species and strains to commercially used chemicals. In British Columbia, the majority of anti-sapstain chemicals are based upon the quaternary ammonium compound DDAC, either as the sole active ingredient or in formulation with co-biocides such as disodium octaborate tetrahydrate (DOT). Ten strains each of the three most prominent blustain fungi found in Canada (Ophiostoma piceae, Ophiostoma piliferum, and Graphium (species C)) were evaluated for their tolerance to DDAC and DOT. The main findings showed there was little or no variation in the tolerance to the chemicals within the strains of each species tested. In the screening tests it was found that DDAC was less effective in inhibiting fungal growth than DOT. However, further examination revealed that the ineffectiveness of DDAC was due to interactions with the media components - a reminder that care must be taken when evaluating results especially with surfactants such as DDAC. Additional work with other sapstain control chemicals is underway.
J Dubois, A Byrne, J E Clark, A Uzunovic


The preliminary evaluation of selected sulfonium salts for use in wood preservation
1984 - IRG/WP 3278
Five sulfonium compounds, including two sulfonium methosulfates, one sulfonium bromide and two amphoteric sulfonium propanesulfonates, were prepared in crude form and subjected to various biocidal screening tests. A rapid screening test in which treated Pinus radiata pulp pellets were exposed to one of three wood-decaying fungi growing on malt agar revealed that dodecyl dimethyl sulfonium methosulfate had an inhibiting effect comparable to that of lauryl dimethyl benzyl ammonium chloride (benzalkonium chloride). The remaining sulfonium salts gave no fungal inhibition in this test. Both dodecyl- and decyl dimethyl sulfonium methosulfate gave a positive response in a screening test for insecticidal activity. However, rapid insect recovery indicated detoxification or excretion of the test chemicals. Dodecyl dimethyl sulfonium methosulfate was also screened as an anti-sapstain treatment with encouraging results. Further work is now in progress to explore the potential wood preservative capability of certain sulfonium and sulfoxonium salts.
D V Plackett


Effect of borate on uptake and efficacy of an anti-sapstain treatment
2005 - IRG/WP 05-30380
The potential for using borates to enhance uptake and efficacy of propiconazole-based anti-sapstain chemicals was assessed on ponderosa pine sapwood wafers. Borates had no consistent effect on either net solution absorption or propiconazole distribution in the wood. Even small amounts of borate, however, markedly improved the performance of propiconazole against fungal discoloration. These results are consistent with previous tests of borate addition to other fungicides and highlight the potential for using less expensive ingredients to boost the performance of more costly biocides.
Jianju Luo, Hua Chen, J J Morrell


The effect of temperature on the rate of fixation of an alkyl ammonium compound (AAC) wood preservative
1984 - IRG/WP 3293
The rate of fixation of an alkyl ammonium compound wood preservative was measured by soaking samples of wood wool in various preparations of the preservative for arbitrary times followed by immediate leaching in water. The wood wool was then analysed for residual preservative. The results indicated that fixation was very rapid and increased at higher temperatures.
P Vinden


Investigation of the fixation in wood of chromated zinc chloride and copperised chromated zinc chloride preservatives
1976 - IRG/WP 372
A biological method of evaluating the extent to which CZC and CCZC preparations are retained in wood in terms of the potential protection which they afford against destruction by Merulius lacrymans (dry rot) is given. CCZC is recommended for protection of wood under moderate leaching conditions, while the use of CZC under such conditions is not recommended.
V N Sozonova, D A Belenkov


Leachability of borate-modified oriented strandboard: A comparison of zinc and calcium borate
2002 - IRG/WP 02-40232
The leachability of boron in zinc and calcium borate-modified oriented strandboard (OSB) was investigated in this study. The leaching experiments were conducted by exposing edge-sealed OSB samples under running water for 8, 24, 72, and 216 hours. The results were compared with those from the unleached controls. Boron leaching of the modified OSB occurred upon the initial water exposure, and the leaching rate decreased as the leaching time increased. Borate type, initial BAE level, wood species, and sample thickness swelling significantly influenced the leachability. There was no consistent effect of polyethylene glycol (PEG) on zinc borate leaching. Calcium borate with a smaller particle size helped reduce its leachability. The glueline washing due to thickness swelling of the test samples under water and decomposition of the borate to form less water-soluble boric acid are thought to be two possible causes for the observed leaching. The relationship between assayed BAE and leaching time followed a decaying exponential function for zinc borate OSB and a Harris decaying power function for calcium borate OSB. The material constants of the regression models allow comparing leachability of the modified OSB for various wood species. A unified leaching method for treated wood composite materials is needed.
S Lee, Q Wu


Inhibition of wood decay and termite damage by calcium precipitation
1996 - IRG/WP 96-30111
Fungal decay of wood in service, especially brown rot, results in billions of dollars (US) of losses annually. Recent environmental restrictions, both U.S. and international, are limiting or eliminating the use of broad spectrum biocides for wood preservation, primarily due to problems with disposal. In order to design new, environmentally benign methods for control of wood decay fungi, it is essential to understand the precise sequence of biochemical events as wood is colonized. The production of polygalacturonase (PG) and hydrolysis of bordered pit membranes during incipient brown-rot decay has recently been described by our laboratory. One key to pectin hydrolysis by plant pathogens has been shown to be fungal production of oxalic acid which lowers the pH of the substrate and chelates calcium ions. Production of oxalic acid may serve a similar role during incipient wood decay as calcium oxalate has been visualized by scanning electron microscopy during both brown-rot and white-rot decay. Therefore, it was hypothesized that in situ precipitation of existing calcium ions in wood may prevent the cascade of biochemical events involved in colonization of wood by brown-rot fungi, expecially hydrolysis of bordered pit membranes. Preliminary experiments in our laboratory have shown that brown-rot fungi, white-rot fungi, and termites are inhibited from effecting weight loss of wood following pretreatment of wood blocks with the selective water soluble calcium precipitating agent N,N-naphthaloylhydroxylamine (NHA).
F Green III, T A Kuster, L Ferge, T L Highley


Photo-discoloration and Degradation of Wood and its Stabilisation by Modification with Benzoyl Chloride
2004 - IRG/WP 04-40274
Photo degradation of Pinus roxburghii (chir pine) and Hevea brasiliensis (rubber wood) was studied under artificial accelerated weathering conditions in a Xenon test chamber. The irradiated samples were analyzed for color changes and chemical changes. Analysis of colour changes in wood surfaces by UV-Vis. irradiation was carried out using a colour measuring (CIELAB) system and chemical changes were monitored using FTIR and fluorescence spectroscopy. Irradiation modified physical and chemical characteristics of wood surfaces and resulted in rapid colour changes, reduction in lignin content and increased concentration of chromophoric groups on the wood surfaces. Colour changes were correlated with formation of carbonyl groups and lignin decay rate determined by FTIR measurements. Fluorescence emission spectra measured from un-weathered wood shows excitation wavelength dependence. Photo irradiation leads to a rapid reduction in the emission intensity, broadening of spectra and a significant red shift in the emission maximum. Photo stability of wood surfaces esterified with benzoyl chloride was also assessed. The modification was characterized and analyzed by fluorescence and FTIR spectroscopy and photo-stability of modified wood was assessed. Esterification of wood by benzoyl chloride suppressed the colour changes (photo-discoloration) and also reduced the lignin degradation and generation of carbonyl groups on irradiated wood surfaces. Results show esterification of wood with benzoyl chloride was effective at inhibiting photo-degradation of wood polymers.
K K Pandey


Oxalate production and calcium oxalate accumulation by Gloeophyllum trabeum in buffered cultures
1994 - IRG/WP 94-10075
Most basidiomycetous fungi produce oxalic acid as a result of their metabolic activities and nutrient procurement. There is currently a renewed interest in the role that oxalic acid may play in the decomposition of wood by basidiomycete fungi. It has been observed that although most wood degrading fungi have the capacity to produce oxalic acid, not all of these organisms express this capacity equally in the wood environment. In addition, not all of the fungi which produce oxalic acid will accumulate this metabolite. Very often the production of oxalic acid is coincident with the precipitation of oxalate salts such as calcium oxalate. At this time it is unclear as to what controls the differential production and accumulation of oxalate by wood degrading fungi. An investigative series of experiments was established using the brown rot fungus Gloeophyllum trabeum to examine the conditions which favor oxalate production and accumulation as manifested through the production of metastable calcium oxalate dihydrate crystals. Batch cultures which were buffered by base cation exchange sites of mineral amendments stimulated the production of calcium oxalate crystals. The results of these buffering experiments indicate that at pH values below approximately 6.0 there is a diminution of oxalate accumulation, and that a pH environment of approximately 3.0 is consistently attained in weakly buffered cultures inoculated with this fungus. These pH values correspond to the pH optima for oxaloacetase (EC 3.7.1.1) and oxalate decarboxylase (EC 4.1.1.2) respectively, and thereby suggest a mechanism for both pH control and oxalate production and accumulation.
J H Connolly, J Jellison


An investigation of organotin compounds in treated wood using Mössbauer spectroscopy
1983 - IRG/WP 3249
The influence of sample preparation on the 119mSn Mössbauer spectrum of tributyltin chloride in ponderosa pine was investigated. Initial studies with sawdust and compressed discs concluded that the latter were clearly superior. Further studies showed that compressed discs prepared from 0.4 g of treated wood and 0.1 g of cellulose were robust and gave excellent Mössbauer spectra. The possibility of improving the Mössbauer resonance by increasing the solution concentration was evaluated, and found to be beneficial, with no change in the fixation process being evident at least up to 6.9% solution strength. Wooden cores were assessed as alternative test material since they are less prone to disintegration. The Mössbauer spectrum of tributyltin chloride in wood was obtained and analyzed with the aid of point charge calculations. It was concluded that when impregnated into wood, tributyltin chloride either remains polymeric with bridging chlorides or adopts a mer-trigonal bipyramidal geometry with hydroxyl donor bonding from the cellulose. Investigation of tributyltin-, dibutyltin- and monobutyltin-chlorides following impregnation into wood suggested that, while the monobutyltin-derivative may be easily identified when present, it is doubtful whether the tributyltin- and dibutyltin- complexes will be distinguishable using simple Mössbauer spectroscopy. Modifications were therefore proposed for the technique which would allow the triorgano- and diorganotin species to be identified when present as mixtures in wood.
J N R Ruddick, J K Ingram


Inhibition of termite damage by N'N-napthaloylhydroxyamine (NHA): Reticulotermes flavipes (Kollar) vs. Coptotermes formosanus Shiraki
2000 - IRG/WP 00-10354
The calcium precipitating agent NHA has been shown to protect southern yellow pine (SYP) from wood decay and termite damage comparable to CCA in field tests (Gulfport, MS) for two years (Crawford and Green, 1999). In a collaborative study, SYP wood blocks were vacuum treated with three concentrations of aqueous NHA and exposed in a no-choice test to Eastern subterranean termites (FPL, USA) and Formosan subterranean termites (WRI, Japan) to determine protection against termite damage. Individual blocks (leached and unleached) were exposed to R. flavipes (AWPA) or C. formosanus (JWPA) for 3-4 weeks. Mean weight loss of wood blocks after termite exposure ranged from 0.0 to 18.0% for R. flavipes and 6.0 to 20% for C. formosanus. Wood blocks exposed to R. flavipes were completely protected by 0.5 and 1.0% NHA, but weight loss in similar blocks challenged by C. formosanus were 6.0% and 6.2% respectively at the same concentrations. NHA acted as an effective termiticide for R. flavipes with 100% mortality after 3 weeks, but only soldiers were preferentially killed in C. formosanus. Formosan subterranean termite workers showed enhanced resistance to NHA treatment when compared to Eastern subterranean termites.
F Green III, S T Lebow, T Yoshimura


A comparison of inductively coupled plasma spectroscopy and neutron activity analysis for the determination of concentrations in wood
1993 - IRG/WP 93-10048
As wood decays the ionic composition changes, with increases often being seen in the concentrations of Ca, Mg, Fe, Mn and sometimes K. The concentration of eight cations in red spruce sapwood and heartwood samples was determined independently by inductively coupled plasma spectroscopy (ICP) and by neutron activation analysis (NAA) as part of an effort to standardize our analytical procedures and create a uniform wood standard for use by multiple researchers. Preliminary studies indicate a difference in the values of Ca and K as estimated by ICP and NAA, possibly due to a loss of these elements due to volatilization during ashing.
J Jellison, J Connolly, K C Smith, W T Shortle


Decay and mold resistance of borate modified oriented strandboard
2003 - IRG/WP 03-40260
Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwoods and yellow pine was investigated in this study. Tests were done with brown rot, Gloeophyllum trabeum, and white-rot, Trametes versicolar, fungi for 8 and 12 weeks, respectively. Wood species and fungus type had significant influence on the decay resistance. Decay caused by brown rot was evident for all untreated southern pine and mixed hardwood OSB controls. White rot, however, did not cause significant sample weight loss for both species groups. The incorporation of ZB and CB into the OSB provides suitable protection against brown- and white-rot fungi. No significant weight loss was observed from the treated OSB. Microscopic analysis shows that the hyphae were abundant in wood rays and cell walls in the southern pine OSB controls attacked by G. trabeum. Untreated samples from mixed hardwoods and commercial OSB were most susceptible to mold growth. The borate-modified OSB from mixed hardwoods and southern pine effectively prevented the mold growth. Mold resistance was achieved with increase of borate retention level in the samples. Mixed hardwoods OSB showed a higher susceptibility to mold growth than southern pine OSB with or without borate treatment.
Q Wu, S Lee, J P Jones


Field tests of preservative-treated radiata pine in Japan
1995 - IRG/WP 95-30083
Test stakes of radiata pine treated with various alkyl ammonium compound (AAC) formulations and with copper-chrome-arsenate (CCA) as reference preservative were installed in 3 test sites in Japan in 1981-82. When inspected in 1995, CCA-treated stakes showed less decay at all three sites than stakes treated with other formulations. Ammoniacal copper quaternary (ACQ)- treatment was only slightly less effective than CCA at two sites (Tsukuba and Fukiage-Hama), but more markedly less effective at the high decay hazard Uji site. Unamended AAC treatment was least effective, but there was little difference in performance between didecyl dimethyl ammonium chloride (DDAC) and benzalkonium chloride (BAC) formulations.
M E Hedley, K Tsunoda, K Suzuki


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