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Copper binding capacity of modified wood flour
1992 - IRG/WP 92-3709
Wood flour was modified by reaction with oxidising agents and CCA preservative. The copper chromium and arsenic were removed from the CCA treated wood flour by an acid leaching procedure. The modified wood flours were allowed to react with copper acetate solution and the level of copper fixation achieved was determined. The modified wood flours had greater affinity for copper ions present in solution than unmodified wood flour.
N C Milowych, W B Banks, J A Cornfield


Collaborative soft rot tests: Programme and test method
1973 - IRG/WP 229
J G Savory, J K Carey


Iron promotes decay capacity of Serpula lacrymans
1993 - IRG/WP 93-10008
The influence of iron and iron compounds on the decay capacity of Serpula lacrymans was studied. Mass losses of pine wood caused by dry rot fungus were increased when FeSO4 was added into the culture medium or when there were iron nails or stone wool on the culture medium. This supports the hypothesis that iron in stone-based building materials is one reason for the increased decay capacity of Serpula lacrymans.
L Paajanen


Non-enzymatic Gloeophyllum trabeum decay mechanisms: Further study
2001 - IRG/WP 01-10395
Information will be presented on the mechanisms involved in, and potential application of, non-enzymatic wood decay by brown rot decay fungi. Specifically, the hypothesized role of low molecular weight phenolate derivatives will be discussed in relation to non-enzymatic degradation of wood. The mechanism of binding of iron by cellulose, and binding and reduction of iron by fungal derivatives and model compounds is examined. Positive and negative aspects of potential application of these compounds in the generation of free radicals will be discussed.
B Goodell, J Jellison


Production of treated wood in Brazil in 1982 and 1983
1985 - IRG/WP 3327
The data of Brazilian production of treated sleepers, poles, crossarms, fence posts and other commodities are given for the years of 1982 and 1983. This report updates information given to the Group in Document No: IRG/WP/3321 Wood Preservation in Brazil, STU information no 445
M S Cavalcante


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


A new laboratory technique devised with the intention of determining whether, related to practical conditions, there should be a relationship between growth rate and decay capacity (of different strains) of Serpula lacrymans
1989 - IRG/WP 1384
Most laboratory techniques for the determination of growth rate not only use a medium (agar) unrelated to practice, but also yield values that are often far less than those found in practice. Also, most laboratory techniques for the determination of decay capacity ensure that the whole of a small test block becomes fully surface-colonised within the first few days; whereas in Australian practice Serpula lacrymans most often grows in one direction, from the walls across floorboards, with resulting collapse first evident near the ends of boards adjacent to that wall. This paper reports on a new, medium-scale, laboratory technique enabling growth rate measurements and (subsequently) a decay capacity measurement, all using the same piece of timber. Eight strains of Serpula lacrymans have been used in the three evaluation experiments carried out to date. Mean values for growth rate on wood have been suitably high, probably as high as for the most favourable practical situations. Resulting mass losses have, as was intended, been reduced in comparison with values previously obtained in small-scale techniques. This direct technique has confirmed the conclusions that others have made based on their comparisons; that it seems unlikely that the pattern of differences between growth rates of different strains has any consistent similarity with their corresponding decay capacities.
J D Thornton


Report on the status of collaborative experiments within the Sub-group on Basidiomycete tests
1983 - IRG/WP 2194
This report summarises the results of co-operative work carried out within the Sub-Group on Basidiomycete tests up to December 1982. The principle findings are recorded in the Conclusions Section. Work intended between IRG-13 in Turkey and IRG-14 in Australia is cited under Future Programme. An Annex provides a response sheet for existing and new participants to notify their contributions.
A F Bravery


Testing wood in ground contact: An artificial soil
1977 - IRG/WP 280
This document is an interim report on the development of the artificial soil medium. It includes some information on the relationship between soil, wood and water which is of relevance in testing.
E F Baines, D J Dickinson, J F Levy


Iron in stone wool - one reason for the increased growth and decay capacity of Serpula lacrymans
1992 - IRG/WP 92-1537
The chemical compositions of stone wool and glass wool were analysed. There was more iron in the stone wool than in the glass wool. It was found that iron present in stone wool was easily dissolved by oxalic acid that Serpula lacrymans is able to produce. The stone wool promoted the decay of pine wood by Serpula lacrymans. The glass wool had no effect on the decay capacity of Serpula Iacrymans. The iron derived from the stone wool may be one reason for the increased growth and decay capacity of Serpula lacrymans. Transition metals (Fe2+, Mn2+, etc.) combined with hydrogen peroxide (H2O2) are believed to be necessary for the oxidative breakdown of polysaccharides.
L Paajanen, A-C Ritschkoff


An investigation into the influence of soil cation exchange capacity on preservative component depletion
1994 - IRG/WP 94-20050
The mobility of preservative components from treated wood into the soil environment is regarded as an important determinant of preservative performance. Standard procedures for the investigation of this phenomenon have not been developed to any great extent. Soil bed studies conducted in this laboratory using natural soil and modified soil media have provided interesting comparative data on the influence of cation exchange capacity on preservative depletion. Some of these data are discussed with reference to the development of a standard soil contact depletion procedure.
K J Archer, L Jin


Soil-bed studies. Part 2: The efficacy of wood preservative
1983 - IRG/WP 2205
Various methods of decay assessment were investigated. Three stages or phases of decay were identified which could be used to describe the efficacy of a preservative system or virulence of a soil-bed testing medium. These included the lag, decay, and senescent phase. Premature senescence could arise if wood samples became waterlogged. It was concluded that time to failure was unsuitable as a method of decay assessment. Decay assessment by deflection testing was therefore limited to assessing linear losses in elasticity against time.
P Vinden, J F Levy, D J Dickinson


Preliminary studies to assess the effects of aeration and lowered humidity on the decay capacity, growth and survival of the dry rot fungus Serpula lacrymans (Wulf ex. Fr.)
1997 - IRG/WP 97-10208
Novel microcosms were used to test separately the effects of aeration and humidity on the decay capacity, linear spread and survival of Serpula lacrymans. The application of a pumped air supply resulted in an effective cessation of fungal activity when all but the lowest of the air flow rates was used. Furthermore, the lowest air flow rate caused marked growth tropisms away from the stress. In separate chambers used to create a range of relative humidities, growth and decay were permitted only in the higher humidity regimes. In both the air flow and the humidity experiments, the loss of growth and decay abilities was not always accompanied by a loss of fungal survival. A test to compare the decay capacities of domestic building isolates and "wild" Himalayan isolates of S. lacrymans was also performed, as were comparisons of radial growth rates on malt agar. Significant differences between the two groups occurred in both tests.
G A Low, J W Palfreyman, N A White, H J Staines, A Bruce


A study of the colonization of wood blocks in a laboratory unsterile soil test
1988 - IRG/WP 2318
CCA treated and untreated beech blocks were exposed to a defined horticultural loam using the method proposed for the collaborative soft rot test in the soft rot sub-group of Working Group Two. At intervals during the incubation wood samples were removed and fungal isolations were made using selective media. Fungi were identified and tested for their cellulolytic ability and their decay capacity in beech in pure culture. Replicate wood samples were examined by microscopy for colonisation and decay.
M T De Troya, S M Gray, D J Dickinson


Intraspecific variability in feeding capacity of Coptotermes acinaciformis (Froggatt) (Isoptera: Rhinotermitidae)
1983 - IRG/WP 1175
This paper describes laboratory studies to evaluate the comparative feeding capacity within and between five mound colonies of Coptotermes acinaciformis (Froggatt). Matched specimens of mountain ash, pine and coachwood were exposed to five replicate 10 g groups of termites from each colony source. After an initial 8-week exposure period, all groups were assessed for vitality and continued feeding capacity on pine specimens for a further eight weeks. The investigation showed within-colony variations to be small, but wide variations between colonies were revealed.
C D Howick, J W Creffield


Effect of soil type and moisture content on soft rot testin
1986 - IRG/WP 2270
Several soils of different types were tested at a range of moisture contents for their suitability for use in a soil burial soft rot test. Their effectiveness was assessed by weight loss in CCA treated and untreated beech and birch outerwood. A horticultural loam (John Innes No. 2) was the most appropriare soil in terms of amount of weight loss caused, tolerance to changes in soil moisture content and the coincidence of the optimum moisture content for decay in all of the types of woodblock tested.
S M Gray


Status of wood preservation industry in India
2005 - IRG/WP 05-30388
The paper traces the history of wood preservation industry in India, listing various mile stones for creation of treating capacity. The preservation industry developed with the development of rail road system on the line of most other developed countries. The most popular wood preservatives are CCA, CCB, ACC, Creosote and recently LOSP have also appeared in the market. The major users of CCA is the Cooling tower industry, which use more than 50% of the current CCA produced in the country. CCB and Boric acid :Borax rule the furniture industry. The use of LOSP is picking up as brush on applications and in the remedial treatments. The overall picture of preservative used (around 1350 tons CCA equivalent) is quite disappointing considering the volumes of non-durable woods used annually 22.5 million m3.
S Kumar


Soft-rot in Tabebuia sp. wood used in water cooling tower: identification and degradation capacity of the fungi
1998 - IRG/WP 98-10253
Tabebuia sp. (ipe), a native Brazilian wood, is considered of high natural resistance to decaying fungi, and has been used in harsh environments, as cooling towers. Fifty-one fungi, belonging to mitosporic fungi group (Fungi Imperfecti), were isolated from deteriorated Tabebuia sp. wood samples, collected from the mist eliminator and packing of a cooling tower in operation for about 23 years. The degradation capacity of these fungi was evaluated by soft-rot tests using Eucalyptus grandis and Pinus elliottii wood. The microscopic examination of wood sections showed that Acremonium sp., A. kiliense, Phialophora sp. and Phialophora butyrii caused type 1 soft-rot attack in both mod species, while Fusarium oxysporum, Gliocladium spp., Moniliella-like, Penicillium sp., Pullularia pullulans, Trichoderma spp. and Verticillium sp. were not able to produce the same attack. These results and the analyses of weight loss suggested that Acremonium spp. and Phialophora spp. more important decaying organisms of Tabebuia sp. in the cooling tower.
S Brazolin, M Tomazello, I H Schoenlein-Crusius


The effect of added nutrients on growth rate and decay capacity of Serpula lacrymans
1990 - IRG/WP 1427
At the previous meeting a new technique was presented that enables both fungal growth rate and wood decay rate to be measured using the same timber specimen. The technique (IRG/WP/1384) has previously been carried out with 1% malt as the sole nutrient within the small jar that provides the inoculum for this method. Results presented here relate to an additional level of 5% malt, with or without a nitrogen source in the form of ammonium sulphate at either 0.01 g or 1.0 g per litre. Two isolates of Serpula lacrymans (one of European and one of Australian origin) were used at a temperature setting of 20°C. The linear growth front was measured, on the 200 mm long specimens of Pinus radiata sapwood, between 10 and 21 days after the specimens were introduced to the inoculum. Mass loss values of these same specimens were determined after 12 weeks' exposure. Replication comprised three specimens, within each of three large jars, of each treatment. For both strains, increasing the malt level caused some reduction in growth rate, with the addition of nitrogen resulting in no further growth rate changes. In contrast, mass loss of timber was increased for both strains at the higher malt level. Furthermore, for each of the two malt levels tested, the mass loss due to both strains was further increased at the high nitrogen level.
J D Thornton, A McConalogue


A comparative analysis of Coniophora olivacea (Fr. ex Pers.) Karst. and Coniophora puteana (Schum. ex Fr.) Karst. test strains
1993 - IRG/WP 93-20004
Investigations were carried out to compare pure cultures of Coniophora olivacea (Fr. ex Pers.) Karst. used as a test fungus in Australia and other Pacific countries, and Coniophora puteana (Shum. ex Fr.) Karst. which is used in Europe. Comparisons included morphology, growth rate and dry mass of mycelium, decay capacity, influence of temperature, toxic value of CCA and quaternary ammonium compound (QAC) in both an agar-plate method (ED50, ED100, LD100), and a modified agar-block method. The fungi were found to be similar in many respects.
J Wazny, L J Cookson


A comparison of fungal strains used in the bioassay of wood preservatives
1984 - IRG/WP 2220
Previously published data are presented relating to a number of strains of wood-destroying basidiomycetes (Coniophora puteana, Coriolus versicolor, Gloeophyllum abietinum, Gloeophyllum sepiarium, Gloeophyllum trabeum, Lentinus lepideus, Poria placenta, Fibroporia vaillantii and Serpula lacrymans) commonly used as test fungi in the bioassay of wood preservatives. The data, which has not been statistically compared, consists of mycelial growth rates, decay capacities, and toxic values using agar, agar-block and soilblock methods based on data published over a period of almost 50-years. In many cases a large variation can be observed between strains originating from the same geographical region and between strains from different climatic-geographical zones. The differences between individual sub-cultures of the same strain, as used in various laboratories - or even in the same laboratories - are noted. Many of the published bioassay methods contain insufficient detail to make statistical assessments. Therefore, the authors have not attempted a definitive comparison of the numerous data. A proposal is presented to organize an international resource of pure cultural strains used as test organisms in bioassays of wood fungus may be dictated by local requirements.
J Wazny, H Greaves


A comparison analysis of eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray
1991 - IRG/WP 2362
Investigations were previously carried out to compare eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray (some used in various countries as standard test strains): FPRL 12C (England), FPRL 12E (Germany), Warsaw III (Poland), HFP 7802 (Japan), DFP 16508, 16509, 16521 and 16522 (Australia). Studies included growth rate and dry mass of mycelium, decay capacity, reduction of compression strength, toxic values of CCA and NaPCP tested with agar-plate method (ED50, ED100, LD100) and a modified agar-block method using mass-loss and reduction of compression strength criteria. All of the data obtained are presented here together for the first time, in both table and graphic formats. Further comparison between these results will be presented later (in the final part of the series in 'Holzforschung').
J Wazny, J D Thornton


Effect of fungal attack on maximum load capacity of simulated wall assemblies
2007 - IRG/WP 07-20363
The effects of moisture intrusion and fungal attack on the maximum load capacity of nailed assemblies was investigated using one white and one brown rot fungus against 4 material combinations over a 20 week period. Wetting significantly reduced the maximum load capacity of all four material combinations, while wetting and autoclaving only affected the OSB sheathing/spruce stud. The white rot fungus (Trametes versicolor) had no significant effect on the maximum load, while the brown rot fungus (Gloeophyllum trabeum) produced significant load reductions on shear connector assemblies with OSB sheathing. Results indicate that moisture remains the dominant factor in the performance when water intrudes into wall assemblies.
N Melencion, J J Morrell


Thermal treatment of Nigerian-grown Albizzia zygia and Funtumia elastica wood in soy oil medium.
2008 - IRG/WP 08-40413
Thermal treatment in soy oil medium is one of the techniques used as a substitute to the chemical treatment in wood preservation. However, the effects of this technique vary from one species to another and hence the need to investigate the response of individual species to it. Thermal treatment of air-dried Nigerian-grown Albizzia zygia and Funtumia elastica wood was carried out in a vessel containing soy oil at a temperature of 220°C for 2hours. This was followed by the determination of hygroscopy and swelling by water soaking method; surface energy by the sessile drop contact angle method; pH and buffer capacity by the cold extraction method. The process of soy-oil thermal treatment resulted in significant reductions in hygroscopy, swelling properties and pH in both species with accompanying increase in buffer acid and alkaline buffer capacity. The surface energy which is an indication of wettability was reduced in Albizzia zygia but increased in Funtumia elastica. The reductions in hygroscopy and pH are indications of cellulose degradation during the heat treatment process leading to build up of acid formation. The reduction in hygroscopic behaviour indicates potential for stability in wood-water relationship especially when the material will be used in a continuously-changing ambient environment. The reduction in surface energy in Albizzia zygia implies that soy-oil-thermally modified wood from this species will have reduced interfacial attractions with most chemical adhesives. On the other hand, the increase in surface energy in Funtumia elastica shows possibility of improvement in the level of interfacial attractions between wood (substrates) and adhesives. The reduction in pH in both species is expected to have a two-way effect; a benefit through reduction in adhesive curing time and an adverse effect through expected reduction in strength properties.
L Awoyemi


Vacuum drying of European oakwood: Color, chemistry and anti-oxidant potency of wood. Improving appearance in forest value added products
2008 - IRG/WP 08-40432
In hardwoods used for decorative and appearance purposes, wood colour is one of the most important factors of wood quality; in addition colour is related with durability and biological decay of wood. Wood discolouration during drying is mainly affected by heat, light, physiological reactions, combinations of reactions, biochemical and chemical reactions, and micro-organisms attack. In freshly felled and stored round wood discolorations are initiated predominantly through physiological reactions of living parenchyma cells. Discolouration during kiln-drying decreases the commercial value of hardwoods, since hardwoods are used in the manufacture of furniture and cabinets. On one hand, heat modifies the cell wall components and induces chemical reactions of nutrients and extractives, by other hand the role of oxygen in kiln dryers is very important due to oxidation reaction of phenolic compounds. The formation of coloured substances from a phenolic compound oxidized with air and the formation of dark materials from hydrolysable extractives are considered causes of discolouration. In order to reduce oxidation reaction, vacuum drying process can be used. In addition, it offers reduced drying times and higher end-product quality in comparison with conventional drying operations. Operating at low pressures reduces the boiling temperature point of water and enables an important overpressure inside the material which is advantageous for drying and especially for species that do not support a high temperature level. In this work, experimental results for the vacuum drying of oakwood with conductive heating are presented for different drying conditions. In particular, surface-wood scans, antioxidant capacity of wood, Fourier Transform Infrared Spectra of dust-wood for different vacuum and convective drying conditions. Sample temperatures and pressure in the dryer are logged during drying. The experimental setup (Figure 1) is a vacuum chamber where pressure is regulated between two values (Pmin, Pmax). The chamber is built in glass; one balance is kept inside the chamber in order to log the mass variation of the sample. A thermometer gives the dryer temperature. The heating source is an electrical resistance which temperature is controlled with the help of a PID controller. Experiments are performed on Oakwood disks (7 cm diameter and 2.5 cm height). The conductive heat source is maintained at different temperatures (46°, 61° and 70°C) and pressure in the chamber is controlled at different intervals (60-100, 150-200, and 250-300 mbar). Temperature inside the wood sample is obtained at two different positions. Conventional drying is carried out for comparison in a tunnel dryer. Antioxidant potential in fresh and dry wood samples is determined by using ABTS+• radical cation method. The top surface of vacuum-dried specimens is imaged with an HP scan. Finally it is shown that oak wood which is prone to discolour is degraded by different mechanisms depending on drying method. Our results suggest that oxidation of extractives and thermal degradation of hemicelluloses are the principal mechanisms of degradation, but its importance depends on drying method. Oakwood can be dried under vacuum conditions with an acceptable diminution of discolorations due to low temperature and reduction of oxygen amount with acceptable drying rates.
S Sandoval, W Jomaa, F Marc, J-R Puiggali


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