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Antagonistic effect of Trichoderma spp. against Serpula lacrymans in the soil treatment test
1991 - IRG/WP 1473
Soil treatment tests for preventing growth of Serpula lacrymans were conducted using Trichoderma spp. as antagonists. Soil specimens tested were Kanuma-soil without organic matter and the horticultural soil which was collected from the test site of the stake test. Perfect efficacy of treatment with Trichoderma spp. was shown when the horticultural soil without sterilization was used as a soil specimen.
S Doi, A Yamada


The effect of treatment temperature on the biological performance of CCA treated wood
1990 - IRG/WP 3624
Birch and Scots pine sapwood blocks were treated with several concentrations of CCA at three different temperatures: 5, 20 and 35°C. The treated wood was maintained at the appropriate temperature for the fixation period. Leached and unleached samples were then exposed in a soft rot monoculture test using Chaetomium globosum and a brown rot monoculture test using Coniophora puteana. The treatment temperature had little effect on the performance against brown rot but the performance of birch against the soft rot improved as the treatment temperature increased particularly after leaching.
S M Gray


Remedial treatment of wood attacked by insects
1981 - IRG/WP 3175
A review is presented of remedial treatments against wood-boring insects in wood in service. Preconditions and fundamental principles of insect control are compared with the control of fungal attack and reasons are given for the fact that remedial treatments against insects are more commonly applied than against fungi. With regard to insect control measures with a simultaneous preventive effectiveness, information is given on preservatives, control measures as well as on testing the effectiveness of preservatives with eradicant action. An evaluation of 40 tests according to EN 22 or DIN 52164 revealed that a mean depth of effectiveness of 15 mm is obtained at mortality rates of 80-84% of Hylotrupes larvae. At a mortality rate of below 75% the mean depth of effectiveness was about 10 mm and above 90% it was about 27 mm. Among the control measures without any preventive effectiveness fumigation and hot-air treatments are referred to. With regard to biological control measures, practical results are not yet available.
H Kühne


Improved preservative penetration of spruce after pre-treatment with selected fungi. II. Creosote treatment, analysis and strength testing
1998 - IRG/WP 98-40106
This paper describes the creosote treatment and analysis of logs pre-treated with selected fungal agents as a method of increasing the porosity of the wood prior to preservative treatment. The paper also reports the subsequent strength testing of the timber to evaluate the effects of the fungal pre-treatment on the structural integrity of the wood. European spruce logs were pre-treated with either Phanaerochete chrysosporium, Dichomitus squalens, Trichoderma viride and Trichoderma aureoviride for incubation periods of between 1-4 weeks (see Rosner et al. part I) prior to pressure treatment with creosote in a commercial treatment plant. Results indicated that penetration of preservative was increased from between 4-10 mm in controls to 17-32 mm in biologically pre-treated material. Mean creosote loadings in the bio-treated logs were all greater than 125 kg/m3 . These improvements in preservative treatment were achieved with no measurable loss of strength by the two Trichoderma strains while each of the basidiomycetes caused only a 10% decrease in strength. The implications of the work for the improved preservation of Spruce is discussed.
E J Tucker, A Bruce, H J Staines, B Rosner, K Messner


Improved preservative penetration of spruce after pre-treatment with selected fungi. I. Fungal pre-treatment of pole sections
1998 - IRG/WP 98-40117
European spruce logs were pre-treated with either Phanaerochete chrysosporium, Dichomitus squalens, Trichoderma viride and Trichoderma aureoviride for incubation periods of between 1-4 weeks prior to pressure treatment with creosote in a commercial treatment plant and analysed for strength and creosote uptake (see part II Tucker et al.). A method to pre-treat logs was optimised. The pole sections were surface sterilised, inoculated with a spore suspension or blended fungal mycelium and supplemented with a nutrient solution. The colonisation of the logs was investigated by light microscopy, SEM and by an ergosterol method, quantifying the fungal biomass in the wood. The assays indicated a rapid and even colonisation of the wood down to the heartwood within a period of approximately 1 week. Dichomilus squalens was also seen to colonise the heartwood. The microscopic and quantitative assays correlated well and reflected the depth of penetration of creosote on subsequent treatment. SEM observations showed that the increased permeability is due to an enzymatic opening of the pit membranes rather than physical penetration of the pits by fungal hyphae.
B Rosner, K Messner, E J B Tucker, A Bruce


Biological resistance of steam-compressed wood pretreated with boric compounds
1999 - IRG/WP 99-30190
Wood compression under heating is aimed to enhance dimensional stability and surface hardness. Preservative treatment with an appropriate chemical is additionally required for the protection of wood against biological agents under hazardous service conditions. Boron pretreatment of compressed wood was targeted to a mutual benefit of increasing biological resistance of compressed wood as boron was converted to a more stable form through hydration and dehydration reactions under steaming at elevated temperatures in a closed system. Accordingly, boric acid (BA) (at 0.25, 1.00 and 4.70% aqueous concentration)- or phenylboronic acid (PBA) (at 0.34, 0.50, 1.00 and 2.00% aqueous concentration)-impregnated Japanese cedar (Cryptomeria japonica D. Don) specimens were compressed at their radial direction to 50% dry set at 171, 180 and 200°C. The compressed specimens were subjected to decay and termite tests following exposure to a severe ten-cycle wet/dry processes according to Japanese Industrial Standard JIS K 1571 (1998). BA pretreated-compressed wood exhibited remarkable resistance against a white-rot fungus, Trametes versicolor, but not so effective against a brown-rot test fungus, Fomitopsis palustris even at high boron loads which resulted in a high termite resistance. PBA pretreatment appeared to be very effective against both decay fungi and Formosan subterranean termite when wood specimens were compressed at high temperatures and steam pressure.
M K Yalinkilic, W Dwianto, Y Imamura, K Tsunoda, M Takahashi


Shorter-term biological control of wood decay in pre-seasoning pine roundwood as an alternative to chemical methods
1992 - IRG/WP 92-1555
Previous studies on the long-term control of decay in creosoted transmission poles, using Trichoderma and other antagonistic moulds, have met with limited success. However, it is possible biological control is more suited to control of decay on shorter time scales. An earlier study, focusing on pre-seasoning treatment of transmission poles showed that favourable porosity increases could be brought about by an isolate of Trichoderma. Furthermore, it was evident that considerable improvement could be made in developing antagonistic strains of Trichoderma. A study further investigating the use of antagonistic primary mould fungi as biological control agents is outlined.
M W Schoeman, D J Dickinson


Biological Protection of Composite Panel from Moulds and Decay
2007 - IRG/WP 07-10612
Composite panels, such as oriented strand board (OSB), are widely used in house construction in North America. These structural panels are normally made of non-durable wood species and are susceptible to moulds and decay when exposed to wet conditions. Building envelope failures due to moulds, decay or poor construction practices can negatively impact the image of wood. To ensure durability of composite panels, the most important consideration is the use of mould- and decay-resistant wood species to prevent fungal attack. Using low environmental impact technology to improve the durability of composite products could have market-related advantages over using chemical protection products. This research aimed to explore various potential biological treatments to protect composite panels from biodegradation, and to increase durability of panels for better resistance to mould and decay infection in service.
Dian-Qing Yang, Xiang-Ming Wang, Hui Wan


Effect of a biological treatment on below ground decay of Douglas-fir pole sections
2008 - IRG/WP 08-40433
The use of exogenous sugars to accelerate microbial growth and eventually limit available oxygen in soil surrounding wood in soil contact was investigated on untreated Douglas-fir poles exposed over a 3 year period in Western Oregon. Isolation frequencies differed markedly between treated and untreated poles and the treatment did appear to shift the frequency of some basidiomycetes. The treatment was also associated with slight, but not significant delays in loss of surface integrity for the first 2 years of the test. These differences, however, disappeared after 3 years. The results suggest that exogenous sugars can alter the composition of the fungal flora in the soil surrounding untreated wood in soil contact, but the decay capabilities of that modified flora do not differ markedly from that present in the unaltered soil.
C Freitag and J J Morrell


Effect of different ASAs (alkenyl succinic anhydrides) on the treatment of biological protection of wood in use class 4
2008 - IRG/WP 08-40440
The alkenyl suscinic anhydrides (ASAs) used in this work are adducts resulting from the maleinization reaction of fatty acid alkyl esters. Various products with different alkyl groups were synthesized from rapeseed (Brassica napus) oil esters, rich in oleic acid. The liquids obtained showed a viscosity similar to that of vegetable oils and a brown color. When applied into wood, a thermal treatment allows them to react with cellulose and lignin creating covalent bonding. It is supposed that the enzymes produced by fungi or the stomach of termites are not able to degrade the esters in treated wood. In this work, the biological resistance was assessed for each kind of ASA.
C Vaca-Garcia, O Pignolet


Biological Treatment to Improve Wood Product Quality and Durability - Fifteen Years of Effort and Experience at FPInnovations-Forintek Division
2009 - IRG/WP 09-40444
Wood plays an important role in the world economy. However, wood is subject to attack from wood-degrading fungi and insects and durability and quality of wood products are becoming increasing concerns for consumers. Development of effective and low environmental impact technologies to improve wood product quality and durability will be required to address these concerns. The application of a biological treatment to wood products is an example of one such technology. During the past fifteen years, a series of research projects were conducted at FPInnovations–Forintek Division to explore and develop various biological technologies and treatments to improve wood quality and durability against mold, stain and decay. These projects included 1) biological protection of logs and green lumber from mold, stain and decay; 2) biological pre-drying of wetwood lumber; 3) biological treatment to improve wood panel durability; 4) biological modification of wood to reduce resin use in panel manufacturing; and 5) biological incising to harden wood. This article summarizes the significant technical breakthroughs and findings made in these studies.
Dian-Qing Yang


A comparative study and evaluation of methodologies used for determining wood preservative penetration
2011 - IRG/WP 11-20475
A series of methods for determining penetration of wood preservatives into the wood structure have been developed for either quality control (QC) or research and development purposes. QC methods range from monitoring the solution uptake, applying colour indicators or sampling specific wood samples followed by wood acid digestion/atomic absorption spectroscopy (AAS) or solvent extraction/chromatography analysis. Several standard methods for penetration analysis were developed by various standardization groups (e.g. AWPA, CEN). They are mostly used in correlation with a specific wood preservative system. Additional analytical tools are necessary for detailed penetration studies, especially during product development of a new wood preservative. Sufficient penetration of the active components into the wood structure plays an essential role in determining the service life of treated wood. Depending on the desired end use (use class) of the treated wood component, different penetration requirements apply. Therefore studying and optimizing the penetration characteristics of new wood preservatives must be an integral part during their development. Furthermore monitoring that the penetration requirements are fulfilled in the wood treatment process is an important aspect to ensure the quality of treated wood products. The aim of this study was to review several methods currently employed to determine the penetration of the wood preservative actives e.g. colour indicators, solution uptake of treated wood, direct gradient studies by wood acid digestion/atomic absorption spectroscopy or solvent extraction/chromatography analysis, and microbiological studies using different types of fungi. Factors which can impact on the outcome from these methods are being discussed based on some “model” wood preservative systems.
R Craciun, R Moeller, J Wittenzellner, T Jakob, J Habicht


The potential of propolis and other naturally occurring products for preventing biological decay
2011 - IRG/WP 11-30575
The potential of using a range of naturally occurring plant extracts and propolis from bee hives for enhancing the durability of timber in service as well as helping with the conservation of archaeological timbers is considered in this paper. Results reported demonstrate that there is some degree of protective effect noted, suggesting a viable treatment option might be developed based on a deeper understanding of some of the actives and their suitability for use. The challenges faced in developing a product specifically for wood protection are significant and may be too costly for the returns. To achieve commercial reality would be more likely if the active ingredient could find a role in agriculture e.g. fruit protection, crop protection and other larger scale markets.
D Jones, N Howard, E Suttie


Limited variability in biological durability of thermally modified timber using vacuum based technology
2011 - IRG/WP 11-40567
The SmartHeat® thermal timber treatment is a new technology based on the process parameters being steered very precisely mainly due to the vacuum applied and heating system involved. Timber treated with this technology shows a potential for less variability of biological durability in one batch. Several batch treatments were sampled and assessed on statistical variability of decay resistance against Basidiomycetes and soft rotting micro-fungi according to lab testing as described in the standards CEN/TS 15083 part 1 and 2 respectively (only Basidiomycetes test results are reported in this paper). By means of Weibull distribution assessment it was possible to show that variability in biological durability of each treated beam is well controlled and that this variability is limited compared to natural durability of wood species. Lower treatment variability due to precise parameter control for each beam and limited deviations of process parameters within the treating vessel are considered the main contributing factors. The paper also states that lower control of process parameters of some heat treatment processes might induce higher variability of the obtained biological durability than a customer might expect.
J Van Acker, S Michon, J Van den Bulcke, I De Windt, B Van Swaay, M Stevens


Development of a new method for wood hydrophobizing and fixation of copper compounds by chemical hardening of vegetable based modified oils
2016 - IRG/WP 16-40754
Wood products with ground and direct water contact, but without sufficient biological durability, have to be protected against biological degradation by fungi and other microorganisms. Due to European legislation (Biocidal Products Regulation 528/2012), the selection of possible chemical agents, which are still allowed to be used, is diminishing rapidly. The use of previously widely applied, very effective substances, as creosote, organic chlorine or hexavalent chromium fixed water soluble cuprous salts e.g., is no longer allowed or strongly limited. Hence, it makes sense to develop new approaches for hydrophobizing wood, which solve the problem of agents leaching in the meantime. The paper presents a method to improve the natural durability of beech wood by means of a vacuum/pressure procedure using on a modified vegetable oil. The oil can be hardened directly in the inner wood zone by means of microwaves and oxygen treatment. This shall prevent the commonly occurring disadvantages of oil treatments which frequently cause bleeding by time, affection with microorganisms as bacteria and algae or staining and simultaneously reduce the leaching of cuprous salts. Firstly, as biocide component an aqueous cuprous salt (Cu acetate) solution was embedded before the oil treatment. Secondly, an organic oil soluble copper soap (Cu octanoate) was incorporated directly into the oil component. It could be verified, that the oil can be hardened completely in 1cm depth of beech wood specimens after a 24-hours lasting treatment in an laboratory autoclave with oxygen at 70°C. Thus, the biological durability of beech wood could be enhanced from durability class 5 to class 1-3 (depending on the treatment and tested microorganisms according to CEN/TS 15083-1 and 2). The oil impregnation causes a significant decrease of copper leachability and enhancement of the biological resistance against the basidiomycetes Coniophora puteana and Trametes versicolor after accelerated ageing according to EN 113. Maximal mass loss varies from 1 % to 10 % and allows the utilisation of the treated wood up to use classes 2 and 3 according to EN 335. Tests with soft rot fungi show that the mass loss, which normally varies from 21 % to 36°% for natural beech, could be decreased down to 6 % for treated beech. The resulting x-values (acc.to CEN/TS 15083-2) allow a categorisation into durability class 2 for copper containing variants and 3 for pure oil treatments. The addition of siccatives like cobaltous or manganous salts causes an enforced polymerizing process with higher resistance against water and biological affection. However, in some combinations the copper compounds cause liquefaction of the oils, as there act also as siccatives. In order to find highly efficient receipts, detailed formulation work is necessary according to the choice of the oil, the siccatives and their combinations as well as the hardening parameters.
C Swaboda, M Fischer, K Jacobs


Mechanical and biological durability properties against soft-rot and subterranean termite in the field (grave-yard test) of beech wood impregnated with different derivatives of glycerol or polyglycerol and maleic anhydride followed by thermal modification in an opened or in a closed system
2021 - IRG/WP 21-40917
This paper presents mechanical and biological durability properties in soil beg test (soft-rot test) and field test (grave-yard test) against subterranean termite of the wood modified with an aqueous vinylic derivative of glycerol/polyglycerol or maleic anhydride cured in an opened or in a closed system. Wood modification was performed through impregnation of European beech (Fagus sylvatica) with aqueous solution of polyglycerol maleate, glycerol maleate, or maleic anhydride at 10 or 20% w/w concentration, followed with curing under oven heating (OHT) at 120°C, 150°C, or 220°C in opened system or under heat pressurised steam (HPS) at 150°C in closed system. The modified woods were then characterized for their weight percent gain and mass losses after curing process, mechanical properties [modulus of elasticity (MOE), modulus of rupture (MOR), work to maximum load in bending (WMLB)], and biological durability properties against soft-rotting micro fungi in soil beg test and against subterranean termite (grave-yard test) in a tropical country. Results have revealed that almost all modified wood presented higher MOE values than untreated wood, however, MOR and WMLB decreased up to 27% and 87%, respectively. Biological durability in the soil beg test against soft-rot indicated that almost all modified wood were specified as durable to very durable wood. However, among the treatments, the wood modified with polyglycerol maleate/glycerol maleate/maleic anhydride at 20% under OHT 150°C or the wood modified at lower additive concentration (10%) under OHT 220°C presented significantly better durability against subterranean termite within a period of 328 days in the field.
M Mubarok, H Militz, S Dumarcay, I W Darmawan, Y S Hadi, P Gerardin


Proposal for further work on accelerated ageing
1988 - IRG/WP 2314
M-L Edlund


Biological screening assays of wood samples treated with creosote plus chemical additives exposed to Limnoria tripunctata
1980 - IRG/WP 408
Laboratory methods for exposure of treated wood coupons to Limnoria tripunctata are described. Chemical additions to creosote were screened using this method. Three pesticides, Endrin, Kepone, and Malathion proved particularly effective. The addition of varying percentages of naphthalene to creosote using several treatment methods are currently being assayed. Results to date show that the coupons treated by the empty cell method have better performance than those prepared by the toluene dilution method. The naphthalene coupons treated by the full cell method show no attack after six months' exposure.
B R Richards, D A Webb


Status of the research and development of a new preservative system (EFPL) for pressure treatment of spruce in Canada
1975 - IRG/WP 348
Our work has been to develop a system which would have the stability of the ACA system and the formulation flexibility of the CCA system enabling properties such as fixation of arsenic, water repellency, appearance and cost to be controlled. Our permeability studies of spruce using a method previously developed indicated that an ammoniacal solution of copper arsenate is an excellent candidate for the treatment of spruce. Studies of the permeability of spruce sapwood microsections to CCA preservative and to an ammoniacal solution of copper arsenate proved that the ammoniacal system penetrates 1.7 to 1.8 times faster than the CCA system, in the radial direction. The permeability in the tangential direction was on the average 3.8 times better. These results were confirmed by pressure treatments of spruce lumber and spruce roundwood with both preservatives.
J Rak, M R Clarke


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 2: Report of treatment and installation in Australia
1978 - IRG/WP 440
The purpose of this test and the procedures to be followed have been fully set out in documents distributed by the International Research Group on Wood Preservation and numbered IRG/WP/414 and IRG/WP/420. The prescriptions set out in these two documents have been closely followed.
J Beesley


Field test evaluation of preservatives and treatment methods for fence posts
1985 - IRG/WP 3347
This work presents the field test results after fifteen years exposure of Eucalyptus saligna fence posts treated with six different preservatives and five treatment methods. All the combinations with oil-borne preservatives presented the best results and among the waterborne preservatives, the fence posts treated by immersion method were with the lowest performance in the field test.
G A C Lopez, E S Lepage


Manual of a mini treating plant for waterborne preservative treatment of timber and bamboo
1999 - IRG/WP 99-40130
This contributional article includes machinaries and equipments necessary for a small wood treating plant for the pressure treatment of tim bers with waterborne preservatives along with the cost and design. The preservative treatment limitations, treatment schedules and specifications for different products have been described. The cost of a mini treating plant will be 6,00,000 Tk. (13,000 US$), suitable for preserving timber and bamboo products for indoor and outdoor uses and will out last teak wood. The additional durability of timber and bamboo will create economically and environmentally safe conditions.
A K Lahiry


Penichroa fasciata (Stephens) (Col. Cerambycidae) a pest in wood materials
1988 - IRG/WP 1365
Penichroa fasciata (Stephens) (Col. Cerambycidae) is found to be a frequent pest occurring in hardwood in storage in Italy. This paper reports the characteristic for identification, biological features, distribution and timber liable to attack.
A Gambetta, E Orlandi.


Strength loss associated with steam conditioning and boron treatment of radiata pine framing
1987 - IRG/WP 3438
The combined effect of included defects and wood moisture content on the strength loss of second rotation radiata pine framing following conventional steam conditioning is investigated. The green Modulus of Elasticity (MOE) is reduced by approximately 13% after steaming. When dried after steaming, however, neither the MOE nor MOR is significantly different from unsteamed dried controls.
M J Collins, P Vinden


Soft rot penetration - Effect of groundline maintenance treatment on poles in sevice
1983 - IRG/WP 3263
R S Johnstone


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