IRG Documents Database and Compendium


Search and Download IRG Documents:



Between and , sort by


Displaying your search results

Your search resulted in 193 documents. Displaying 25 entries per page.


Effect of fatty acid removal on treatability of Douglas-fir
1993 - IRG/WP 93-40008
Treatment of Douglas-fir with chromated-copper-arsenate (CCA) poses a major challenge. Several hypotheses based on the anatomical aspects as well as chemical reactivity of the preservative formulations with cell wall constituents and deposits have been proposed. Techniques to prevent pit aspiration or slow fixation reactions have, however, not significantly improved treatment. The presence of high molecular weight fatty acids have been reported to be responsible for higher hydrophobicity in some wood species. These acids can react with Cu+2/Cr+3 ions to form insoluble metallic soaps, thereby immobilizing Cu/Cr and increasing wood hydrophobicity by a mechanism similar to that employed in paper sizing. The effect of fatty acids on treatability was explored by removing these components via several extraction methods. In general, extracted wood had higher gross solution absorptions and chemical retentions, but preservative penetration was largely unaffected. The results suggest that removal or disruption of fatty acids can improve treatability of Douglas-fir heartwood.
S Kumar, J J Morrell


Leachabilty and efficacy of fatty acid derived boron esters as wood preservatives - leachability and efficacy of fatty acid derived boron esters as wood preservatives
2004 - IRG/WP 04-30351
Borates have many advantages as wood preservatives. However, boron is susceptible to depletion under humid conditions and this restricts its outdoor use. In order to reduce boron leachability in treated wood, one of the anticipative approaches is to use organic fixed boron-based preservatives. This study investigated the leachability of six boron ester compounds as potential preservatives. Scots pine sapwood (Pinus sylvestris L.) test specimens were vacuum treated at different concentrations of BAE (Boric Acid Equivalent) of each boron ester active ingredient with and without 10% addition of commercial resin product. Stand-alone boron treatment using 1% BAE disodium octaborate tetrahydrate (DOT) is conducted as a reference. The results of chemical analysis of leachates taken at different periods showed significant differences in boron leachability between the DOT treated samples and specimens treated with both boron esters. Although there are significant differences between the pure boron treatment and the resin protective addition treatment, minor differences were found between boron ester treatments irrespective of resin addition. However, these data allowed the selection of one boron ester compound for further biotesting based on its leaching performance. Results of the biological assays with both Scots pine sapwood and poplar (Populus trichocarpa x deltoides) samples using the European standard EN 113 confirmed the efficacy of the selected boron ester compound against Coriolus versicolor, Coniophora puteana, Gloeophyllum trabeum and Poria placenta. After sixteen weeks of exposure to fungal attack all specimens treated with the new organic boron compound at 0.66 % BAE, irrespective of resin addition, exhibited insignificant mass loss for all four fungi and both wood species tested, which proved the decay resistance of the treated wood.
A Mohareb, J Van Acker, M Stevens


A comparison of fatty acid and molecular profiles for identification of wood colonizing basidiomycota
2003 - IRG/WP 03-20278
Two methods that are currently being employed to detect and identify wood decay fungi are Fatty Acid Methyl Ester (FAME) analysis and Restriction Fragment Length Polymorphism (RFLP) analysis. A FAME library and RFLP library for 9 species and up to 10 strains within each species have been developed. The profiles generated by these methods have been compared for each species and strain to test for accurate species identification and consistency within species strains. Single FAME libraries were created for Trametes versicolor and T. pubescens, indicating that all isolates of these species clustered as a single species. More than one FAME library was created for P. chrysosporium, P. sordida, Gloeophyllum trabeum, G. sepiarium, G. striatum and T. hirsuta, indicating that not all isolates of these species clustered as a single species. Blind samples could not distinguish between isolates of T. pubescens and T. hirsuta nor G. sepiarium and G. striatum. Restriction enzyme digestion with AluI, TaqI, RsaI, HaeIII, DraI, and Hinf reliably resolved species; however, no single restriction enzyme profile was sufficient to resolve all of the species groups. The species groups could be resolved with the combined information from Alu I and Taq I restriction profiles, while the addition of Hinf and /or Hae III restriction profiles improved resolution within species and between species. The addition of all other restriction profiles added more but not significantly more resolution within and between species. The ultimate goal of this work is to develop a sensitive and reliable assay to survey the wood decay community and accurately detect important wood decay fungal species.
T C McElroy, L Prewitt, S V Diehl


Protection of wood for above ground application through modification with a fatty acid modified N-methylol/paraffin formulation
2007 - IRG/WP 07-40378
Hydrophobic chemical modification can be regarded as an alternative approach to conventional wood preservation using biocides in order to protect wood in hazard class 3 according the European Standard EN 335-1. A formulation containing fatty acid modified N-methylol/paraffin and an aluminium salt catalyst was used to change the material properties of wood in order to protect wood from fungal decay and deterioration through weathering. Beech wood (Fagus sylvatica) treated to weight percent gains (WPG) of 10-14% resulted in significant decrease in water uptake in a submersion test of 40-50% when compared to that of untreated wood. The treatment slightly reduced the equilibrium moisture content at 60% and 90% relative humidity by 2% compared to untreated wood. An anti-swell efficient (ASE) of 26.6% was achieved at a WPG of 15.7% and indicated a moderate dimensional stabilisation. Strength properties of treated wood were not reduced by the treatment. In addition to the improvement of water related properties, the durability towards basidiomycetes was highly increased (tested according to EN113); the weight loss at 15% WPG was lower than 3%. Infection by the blue stain fungus Aureobasidium pullulans was significantly reduced in a laboratory test due to the treatment. Outside exposure over 1 year revealed less cracking and blue stain compared to untreated wood. The results of this study show that wood modified with a formulation of fatty acid modified N methylol/ paraffin was able to protect wood applied in hazard class 3 according to the European standard EN 335-1 over a long time period without the application of conventional biocidal products.
Nguyen Hong Minh, H Militz, C Mai


Multifactorial Antimicrobial Wood Protectants
2008 - IRG/WP 08-30484
It is unlikely that a single antimicrobial compound, whether synthetic or natural, will provide the ‘magic bullet’ for eliminating multiple biological agents affecting wood products. Development of synergistic combinations of selected compounds, especially those derived from natural sources, is recognized as a promising approach to improved wood protection. Recent adoption of effective fungicide technology in food sanitation and agriculture to applications in wood protection has led to the development of novel wood protectants. Specifically, formulations that incorporate low molecular weight monocarboxylic acids with selected adjuvants as potential synergists suggest use as fungal inhibitors and possible termiticides.
R D Coleman, C A Clausen


Synergistic effect of boron on Streptomyces rimosus metabolites in preventing conidial germination of sapstain and mold fungi
1992 - IRG/WP 92-1565
We evaluated the synergistic effect of boron (4% BAE solution of Tim-Bor or 4% boric acid) on Streptomyces rimosus metabolites in preventing spore germination of sapstain and mold fungi using plate bioassay, Southern yellow pine and sweetgum block tests, and green pine log sections: sapstain -- Ceratocystis coerulescens, Ceratocystis minor, and Aureobasidum pullulans; mold fungi -- Aspergillus niger, Penicillium spp, and Trichoderma spp. Inhibition of spore germination in plate bioassay by metabolites with boron was more effective than without added boron. Treatment of wood samples with the mixture of boron and unconcentrated metabolites also resulted in the synergistic effect and completely inhibited spore germination of sapstain and mold fungi.
S C Croan, T L Highley


A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been elucidated although two oxalate-forming enzymes, oxaloacetase and glyoxylate dehydrogenase, have been studied in our laboratory. Recently, a new role of glyoxylate cycle in oxalate biosynthesis in wood- rotting fungi has been presented, and the cycle commonly occurred to varying extents among the fungi although they were grown on glucose. Enzymatic analyses showed that isocitrate was cleaved by isocitrate lyase in the glyoxylate cycle rather than oxidized by isocitrate dehydrogenase in tricarboxylic acid (TCA) cycle, and the fungi were found to lack a normal TCA cycle due to the absence of - ketoglutarate dehydrogenase. It is noteworthy that glucose was efficiently converted to oxalate in a theoretical yield of about 80%, accumulating in the culture media of F. palustris. The results further indicate that acetyl-CoA derived from glucose was not completely oxidized to CO2 in TCA cycle but was mainly converted to oxalate with help of the other coupling metabolic cycles, including glyoxylate cycle. Formation of oxalate from several intermediary metabolites using cell-free extracts of F. palustris confirmed that oxalate is also the final product of the metabolic pathway in the in vitro system. Thus, it is proposed as a new concept that most of copper-tolerant brown-rot fungi may acquire the energy by oxidizing glucose to oxalate, i.e. oxalate fermentation expressed in the following equation; Glucose + 5O2 --> 2 Oxalate + 2CO2 + 4H2O.
E Munir, T Hattori, M Shimada


Influence of aliphatic acids on spore germination of wood decay fungi
1984 - IRG/WP 2224
Influences of eight saturated fatty acids (C5-C10, C12 and C16) on spores of four isolates of wood decaying basidiomycetes (white rot fungi: Poria tenuis and Trametes hispida; brown rot fungus: Gloeophyllum trabeum [two isolates]) were observed in-vitro. Spore response after 24 hr on malt extract agar containing 10, 10² , or 10³ ppm of each fatty acid included: no effect on normal germination, delayed germination or restricted mycelial growth, vacuolation and degeneration of spore cytoplasm, or germination inhibition without loss of spore integrity. C7-C10 acids destroyed spores of all fungi at 10² ppm whereas spores remained 'intact' at 10³ ppm of the same acids. C12 destroyed spores of the brown rot isolates but not the white rot fungi, and C16 lacked effect on all fungi at all concentrations. C5 and C6 destroyed spores only at 10³ ppm.
E L Schmidt


Response of the Formosan Subterranean Termite (Coptotermes formosanus) to Cellulose Insulation Treated with Boric Acid in Choice and No-Choice Tests.
2004 - IRG/WP 04-10532
The tunneling ability of the Formosan subterranean termite Coptotermes formosanus Shiraki through a cellulose insulation material containing11.1% boric acid was tested in choice and no-choice bioassays. We examined tunneling behavior and mortality of termites exposed to treated and untreated insulation material in miniature simulated wall voids. In a choice test termites tunneled through untreated insulation in all but one of the replicates used. Termites were unable to fully penetrate any of the replicates containing treated insulation and experienced a significantly higher mortality (78.4 ± 18.4%) than termites exposed to untreated insulation (11.6 ± 5.6%, F = 60.4, df = 1, P < 0.0001). In a no- choice test termites fully penetrated all replicates containing untreated insulation and experienced 37.1 ± 37.2% mortality. Termites exposed to treated insulation in this test experienced a significantly higher mortality of 100.0% (F = 14.3, df = 1, P < 0.005), and did not fully penetrate the treated insulation.
M E Mankowski, J K Grace


Boron treatments for the preservation of wood - A review of efficacy data for fungi and termites
1994 - IRG/WP 94-30037
Boron treatments have been used for many decades for protection of timber from biological attack and also as a fire retardant treatment. In recent years there has been an increased interest in boron treatments as an option for protection of structural timbers&apos; e.g. timber framing used in termite risk areas. This paper reviews efficacy data for both fungi and termites relevant to this end-use.
J A Drysdale


Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration
1976 - IRG/WP 262
This paper investigates the possibilities of reducing the time needed for the determination of the effectiveness of chemical compounds from the point of view of their eventual application to lignocellulosic materials for preservation against decay and soft-rot.
K Lutomski, S S Neyman


Comparative investigations on the influence of wood seasoning, wood properties and temperature on the toxic values of wood preservatives against Hylotrupes egg larvae
1970 - IRG/WP 28
Comparative tests carried out at three institutes indicated the influence of kiln temperature, position of wood specimens in the cross sectional area and test temperature on the toxic values determined in accordance with DIN 52165 with egg larvae of the house longhorn beetle (Hylotrupes bajulus L.). The preservatives applied were boric acid in distilled water and g-benzene-hexachloride dissolved in chloroform; the timber species used was pine sapwood, (Pinus sylvestris L.). The method of seasoning had no influence on the toxic values of boric acid. With the g-BHC, however, the toxic values gradually increased with rising kiln temperatures (20°C, 70°C, 105°C). With boric acid the position of the sapwood samples in the log had no influence on the toxic efficacy; with g-BHC the efficacy was slightly greater in the outer sapwood, compared with the inner sapwood. The test temperatures (20°C, 24°C, 28°C) yielded different toxicity results for boric acid. At 24°C and 28°C the threshold values were somewhat below those of 20°C; they agreed with the values obtained at 20°C after a longer test period. With g-BHC different temperatures did not affect the results. An explanation is suggested for the causes of the influence exerted by the kiln temperature and wood properties on the toxic values of g-BHC. There was good agreement between the toxic values obtained in the different institutes.
G Becker, T Hof, O Wälchli


Options for accelerated boron treatment: A practical review of alternatives
1985 - IRG/WP 3329
Boron wood preservatives are almost exclusively applied by momentary immersion and block diffusion storage. Alternative techniques are described which can be used to accelerate boron treatment. Diffusion coefficients have been derived to define the acceleration of diffusion with increasing temperature. Schedules are described for pressure impregnation of green timber, involving steam conditioning, evacuation and alternating pressure method treatment. Timber Preservation Authority penetration and retention requirements can be met in approximately 4-5 h. The optimum schedule, however, included a 12 hour holding period between steaming and preservative treatment. A method of applying boron preservatives as a vapour is described, Trimethyl borate vapour reacts with wood moisture to form boric acid. The kinetics of this reaction, however, are very fast. This limits treatment to timber dried to very low wood moisture contents.
P Vinden, T Fenton, K Nasheri


Movement of boron from fused boron rods implanted in Southern pine, Douglas fir, red oak, and white oak timbers
1995 - IRG/WP 95-30061
This paper reports the distribution of boron from fused boron rods installed into six-inch (15.2 cm) square timbers of Douglas-fir, Southern Pine, red oak and white oak exposed aboveground. The composition and size of rods was: sodium borate and sodium borate-copper oxide (8.5 x 100 mm²); sodium borate-copper, sodium borate and boric oxide-copper oxide (12 x 76 mm²). The boric acid equivalent was roughly monitored by the curcumin/salicylic acid color test and the presence of copper was detected by the chrome azurol-S reagent. One year after installation of rods, movement of boron was determined by application of curcumin dye to increment cores removed at various distances from the site of boron rod installation. A portion of a sodium borate treated Southern Pine timber was also analyzed by spraying curcumin dye on sawed longitudinal and transverse sections. At 2 years, one foot sections were removed from all timber species, sawed as above, and boron and copper detection reagent sprayed on the sawed surfaces. Movement of copper from rods in all timbers was virtually nil. Both transverse and longitudinal movement of boron from rods was greatest in Southern pine which also had the highest moisture content. Movement of boron was next best in red oak. There was little movement of boron away from the rods in white oak and Douglas-fir.
T L Highley, L Ferge


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


The influence of boric acid on respiratory quotients and methane production of subterranean termites
1995 - IRG/WP 95-10136
The toxicity of boron compounds to subterranean termites (Reticulitermes lucifugus) was studied by analysing changes in the levels of oxygen uptake respiratory quotients and methane production. Termites were fed with filter paper treated at different levels of boric acid, the RQ was evaluated by constant volume manometry and the methane production by gas chromatography. Results are discussed in relation to termite gut symbiontes.
L Nunes, D J Dickinson


A new approach to the maintenance problems of wooden railway sleepers
1986 - IRG/WP 3392
The microenvironment of wooden railway sleepers is being investigated to assess their condition to determine the necessary treatment, repair and replacement criteria. The research work involves the development of an integrity tester to determine the condition of sleepers, a remedial treatment of sleepers by selective application of boric acid and a synthetic repair system.
W Beauford, P I Morris.


Diffusion treatment plants (Latin America - Africa)
1974 - IRG/WP 333
B N Prasad


A field test with Benzotar, an industrial residue, as a wood preservative
1985 - IRG/WP 3349
Benzotar, a residue of production of benzoic acid, was tested in field as a wood preservative. Results, after 6.5 years of exposure, showed that this product presents properties that improve the performance of wood in ground contact. This paper describes these results and presents a discussion an some aspects of its potential utilization in Brazil.
S Milano, L R Silva


Testing of alkylammonium compounds
1981 - IRG/WP 2152
Following laboratory soil block tests which showed that Bardac 20 possessed a fungicidal threshold similar to that of chromated copper arsenate, treated ponderosa pine sapwood stakes were installed in a field test site near Vancouver, Canada. Two years after installation all the stakes show signs of fungal degradation. Seven stakes have been removed from the test due to total loss of strength after only two years, and many others are near failure due to extensive decay. It may be concluded from this study, that under the conditions of the test, Bardac 20 has failed to prevent wood-destroying fungi from decaying the stakes. Further investigation of treated "check" stakes and failed field tested stakes has revealed an uneven distribution of the chemical in some stakes treated to low retentions.
J N R Ruddick


In-situ pressure injection for preservation of rubber wood (Hevea brasiliensis Muel Arg.)
1992 - IRG/WP 92-3688
Rubber wood is widely used for the manufacture of furniture, doors for housing and packing cases. However in an untreated condition it is highley susceptible to sapstain and decay fungi and borers. Its utility gets considerably reduced if the wood is not treated well in time. Preservative treatment has to be given within the period of felling and transport to prevent not only loss of structural properties and wood material. Although Boucherie, hot-cold bath diffusion, pressure impregnation, vacuum-pressure impregnation processes for treating timbers have been successfully employed for protection, but the process in cumbersome and difficult to adopt at the site of extraction. Hence, it was found necessary to evolve a simple and convenient method to treat trees in-Situ. A simple pressure injection technique was adopted to treat the standing tree using an instrument designed at the Institute (IWST). This instrument is easy to operate and inexpensive. It was observed that the movement of preservatives was satisfactory and effective. Samples of wood taken from treated stem of such trees were subjected to attack by brown and white rot fungi in the laboratory. It was observed that wood samples treated with Borax, boric acid and Bavistin (1:1:0.2); Borax, boric acid and Sodium pentachlorophenoxide (1:1.5:1) and Bavistin and Ekalux (0.5:0.5) showed higher resistance to fungi and insect attack compared to boric acid and Borax (1:1) in both laboratory and field conditions. Treated wood also retained natural colour and was free from fungal and insect attack for over 24 months in storage. Studies in this method of treatment of plantations species are in progress.
H S Ananthapadmanabha, V R Sivaramakrishnan


Localization of oxalate decarboxylase in the brown-rot fungus Postia placenta
1996 - IRG/WP 96-10161
Oxalate decarboxylase, the enzyme that breaks oxalic acid down into formic acid and carbon dioxide, was recently detected in mycelial extracts of the brown-rot fungus Postia placenta. Differential centrifugation was used to demonstrate that the enzyme is loosely associated with the hyphal surface. Enzyme activity can be removed by washing the hyphae with a low pH buffer. Only low levels of activity were detected in soluble and membrane-bound intracellular fractions. The presence of the enzyme on the hyphal surface and possibly in the hyphal sheath supports the hypothesis that this brown-rot fungus actively regulates the pH and oxalic acid concentration of its environment.
J A Micales


CCA fixation experiments. Part 2
1989 - IRG/WP 3505
CCA fixation in wood was measured by both squeezing solution from treated wood that had not been dried and analyzing the solution for copper, chromium and arsenic, as well as using a chromotropic acid test to detect the presence of chromium VI. Both methods provide useful information on the CCA fixation process and illustrate that chromium VI disappears as CCA becomes fixed within wood.
W S McNamara


First draft of a monographic card for Fomitopsis pinicola (Fr.) Karst
1980 - IRG/WP 196
P W Perrin


Ground contact performance of wood treated by the MSU process
1990 - IRG/WP 3609
Environmental concerns have prompted a renewed interest in accelerated fixation schemes for CCA-treated wood. Results from stake tests of southern pine (Pinus sp.) treated using a conventional Bethell cycle are compared with matched stakes treated using the MSU Process. The effects of adding boric acid to the preservative formulation are also discussed. Differences among test plots are discussed.
H M Barnes, T L Amburgey, R W Landers


Next Page