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Some studies on fungal deterioration of rubber wood (Hevea brasiliensis)
1980 - IRG/WP 2140
For the sreening of anti-stain chemicals trials with selected agricultural fungicides and new chemicals were carried out. Botryodiplodia theobromae, Aspergillus sp. and Penicillium sp. were used at test organisms. For testing the durability of rubber wood (Hevea brasiliensis) suitable local rotting fungi (Basidiomycetes), based on high degrading power, which may later be employed in standard tests, were isolated: Trametes corrugata, Schizophyllum commune, Lentinus blepharodes, Lenzites palisotii, Ganoderma applanatum, Fomes senex and Polyporus zonalis. Several of the fungicides screened, such as benomyl, thiram, quintozene and captafol, are effective against the blue stain fungus Botryodiplodia theobromae, at fairly low concentrations. However at the levels required, none of them is cost-effective compared sodium pentachlorophenoxide, the preservative currently used for blue stain control in rubber wood. Of the seven Basidiomycetes tested, two of them - Lenzites palisotii and Ganoderma applanatum - were shown to give a high degree of degradation in rubber wood. These species could perhaps be used as test organisms for evaluating wood preservatives in Malaysia.
A Sujan, A G Tan, M Stevens


Effects of air-seasoning on fungal colonization and wood strength of Douglas fir poles
1987 - IRG/WP 1315
Air seasoning economically reduces the moisture content of Douglas fir poles before pressure treatment with preservatives. Advanced decay in poles in service has resulted when decay fungi (Basidiomycetes) colonized poles during air-seasoning and survived the treatment process. These problems have led to recommendations to severely limit this practice. To determine the role of these fungi in peeled and unpeeled Douglas fir poles during air-seasoning in the Pacific Northwest, we identified many of the fungi involved, measured their effect on wood strength, and studied methods for limiting fungal colonization. Over 90 percent of peeled poles air-dried for more than 1 year contained decay fungi, suggesting that air-seasoning in the Pacific Northwest might pose some hazard; however, no significant strength losses were noted in poles dried 1 to 2 years. Poles seasoned for 3 years began to show significant strength losses, but these strength values fell within suggested design parameters for Douglas fir poles. Although Douglas fir poles are colonized by decay fungi as they dry, our results indicate that these fungi do not cause serious damage for at least 2 years. On the basic of these results, we recommend that poles be air dried no longer than 3 years in the Pacific Northwest. We also emphasize the importance of heating air-seasoned wood adequately during the treatment process to kill any fungi present.
J J Morrell, M E Corden, R D Graham, B L Kropp, P Przybylowicz, S M Smith, C A Sexton


Imaging fungal deterioration of wood using x-ray microtomography
1997 - IRG/WP 97-10240
Nondestructive tomographic images of solid Southern yellow pine (SYP) wood and SYP during deterioration by wood decay fungi were obtained by using a new class of synchrotron X-ray computed microtomography (CMT). The CMT images will provide information about spatial relationship between degrading fungi and wood structures. Wood samples were scanned with synchrotron-generated X-rays at high resolution (3 microns) using Charge Coupled Device (CCD) area detectors. The CCD detector array optimizes reconstruction algorithms with 329 x 259 small pixels where 1 row of pixels constitutes a single 2-dimensional slice of a specimen. A total of 500 horizontal slices comprising each data set were stacked to reconstruct a 3-dimensional volume of the specimen. Color images were computer-generated in 2-dimension to portray single slices of select cross or tangential sections and 3-dimensional volumes of the wood. Reconstructed volumes can be viewed on 3-dimensional video by fiber optic link to a 3-dimensional stereo viewing theater. The CMT model developed in this work will provide needed information about the chronology and location of structural damage to wood and aid in determining the chemical mechanisms of lignocellulose degradation.
B Illman, B A Dowd


Bio-deterioration of Southern Pine Stakes at Geographically Different Testing Sites
2017 - IRG/WP 17-20609
Southern pine (SP) sapwood is commonly used in preparing the standardized stakes for performance testing as referenced in the American Wood Protection Association (AWPA) Book of Standards. For example, the standardized above ground test methods E16/E18 and the standardized ground contact test method E7 all use sapwood of SP as the preferred wood species for preservative performance test. In this paper, the decay performance of untreated SP in the above ground and ground contact conditions were examined when the stakes were exposed at geographically different testing sites across the United States, and their decay trend over time at different sites were compared and reported. The results from the E16 test in Hilo, HI demonstrated that untreated SP stakes had a relatively slower deterioration initially, however, the stakes started to have a steep decline after 2 or 3-years exposure in the field. All the stakes had complete failure after approximately 5 – 6 years. The results from the E18 test in Hilo, HI test site showed that decay attack was observed after one-year exposure, and then the average decay rating started to drop markedly with a zero rating after about 5 years. For the Saucier, MS test site, the E18 stake showed minimal decay attack following the first year exposure, and then decay started to take off over the next few years. The stakes failed completely after 5-years exposure. For the Gainesville, FL test site, E18 test stakes appeared to have very slight fungal attack for the first 2 years, then started to show steady decline over the next 5-6 years, and the stakes failed completely after approximately 8-years exposure. The Dorman Lake, MS test site demonstrated similar decay trend as Gainesville site. The results from the E7 stakes installed in Gainesville, FL site started to show quick deterioration after installation, and had a steep decay curve over the 2-years period. Most of the stakes had complete failure after approximately 2-years exposure. In comparison, the E7 stakes installed in the two HI sites and Saucier, MS testing sites appeared to have a less steep decay curve with a complete failure after approximately 3-years exposure. The E7 stakes installed in Dorman, MS had complete bio-deterioration after 4-years in ground exposure.
Jun Zhang, J Horton


Assessing the risk of marine borer attack of the timber trestles and decay of timber above the intertidal zone of the Barmouth Viaduct
2021 - IRG/WP 21-10974
The Barmouth Viaduct is a Grade II* listed structure which carries the single track of the Dovey Junction to Pwllheli line and footway over the Mawddach estuary. It is in a marine environment where timber below the high tide mark is at most risk in Use Class 5 and all timber above in Use Class 3.2, permanently exposed to the risk of wetting. The structure consists of a timber trestle viaduct of 113 timber spans with 5 steel spans over the deep-water channel. It is of historic importance and is the longest functioning timber viaduct in the UK and is a vital link on the Cambrian line. However, the structure is ageing and under attack from a number of biological agents. Within the intertidal zone, the structure is at risk of attack by shipworm. Above the intertidal zone, the structure is permanently at risk of attack by wood decaying fungi. The structure is undergoing a £20 million refit with much of the work focussing on the renewal of timber that has been attacked by biological agents. The combination of an ageing infrastructure and stressed maintenance budgets provides the impetus to develop innovative methods to support the asset management plan of the structure. Understanding the performance of materials and their rates of deterioration may inform design choices. Moreover, understanding the impact of climate change and local environmental factors and how this can change the distribution of marine borers and affect the risk of decay can also support the long-term asset management of the viaduct.
J R Williams


Evaluation of decay and energy properties from thermally modified biomasses during fungal deterioration by NIR-spectrometry
2021 - IRG/WP 21-40922
This study is focused on the prediction of fungal weight loss (WL) and high heating value (HHV) from raw and torrefied waste lignocellulosic feedstocks, according to their exposure duration to wood-destroying fungi, using near infrared spectroscopy (NIR) and chemometrics models. Sugarcane bagasse, coffee husk, eucalyptus and pine shavings were torrefied at 290 °C in a screw reactor, during 5, 7.5, 10, 15 or 20 min. Raw and torrefied biomasses were submitted to a water leaching step and then exposed to white and brown-rot fungi, simulating various storage conditions. WL and HHV were determined and NIR spectra were obtained from each sample modality (including raw and torrefied), after 2, 4, 8 and 12 weeks of fungal degradation. The NIR spectra were used to (i) classify the four different residual biomasses in raw and torrefied forms according to fungal degradation by white-rot and brown-rot fungus; (ii) to predict the WL during fungal exposure and to (iii) predict the HHV of the samples according to their decay exposure types and duration. Partial least squares regression (PLSR) or discrimination analysis (PLS-DA) models were built to perform these predictions from NIR spectra. PLS-DA models classify successfully the four different residual biomasses in raw and torrefied forms according to fungal decomposition. PLSR models to predict the HHV during their decay deterioration showed potential utility in an industrial context as a standardized continuous method. Otherwise, PLSR models to estimate the WL due to fungal degradation did not present good accuracy but can be useful for screening in decision making. Further studies are required to improve and develop more efficient models to predict the fungal degradation level of stored raw and torrefied biomasses. These results highlight the potential of NIR spectroscopy as a simple, fast, and efficient tool to analyse the fungal decomposition process over the time.
B de Freitas Homem de Faria, P Santana Barbosa, J Valente Roque, A de Cassia Oliveira Carneiro, P Rousset, K Candelier, R F Teofilo


Introduction to the project ‘Deterioration and decay of wooden cultural heritage in Arctic and Alpine environments’ (ArcticAlpineDecay)
2022 - IRG/WP 22-10997
The Arctic is already affected by climate change, and this is expected to accelerate over the coming decades. Alpine regions in Norway are projected to face similar challenges. Current knowledge on Norwegian wooden cultural heritage in Arctic and Alpine regions is scattered and contains significant knowledge gaps. Historically, - scientists, sectorial governance, tourist trade and commerce have mainly worked from their own expertise and experience regarding wooden cultural heritage in Arctic-Alpine regions. Hence, the challenges wooden cultural heritage in Arctic-Alpine regions are facing urgently need an integrated cross-disciplinary approach. This communication paper gives a short background and an introduction to the project ArcticAlpineDecay. The project ArcticAlpineDecay will use state-of-the-art methods within different areas of expertise, and the novelty of the newly started project is the expected synergy of combining information from different methodologies. We also expect synergy with two ongoing Norwegian projects, CULTCOAST and PCCH-Arctic, and these projects are therefore also briefly described.
G Alfredsen, L Ross, A W Hegnes, M S Austigard, J Mattsson, N B Pedersen, A Sinitsyn, V V Martens, A-C Flyen


Questionnaire - Fungal decay types
1985 - IRG/WP 1265
T Nilsson


Improvements of monitoring the effects of soil organisms on wood in fungal cellar tests
1996 - IRG/WP 96-20093
Accelerated testing the durability of preservative treated timber in a so called "fungal cellar" or "soil-bed" to evaluate its performance in ground contact is widespread practice. In order to obtain a more accurate and reproducible estimate of preservative performance, several institutes, among them the BAM in Berlin, have routinely carried out static bending tests in addition to visual examination. These tests were usually performed with a defined maximum load or deflection path regardless of the remaining degree of elasticity of the test specimens. Recent studies at the BAM revealed that by modifying the method, i.e. by restricting the applied load to the non-destructive interval for each individual test specimen, the calculated modulus of elasticity (MOE) reflect the changing strength properties caused by biological deterioration and allow within a relatively short time valuable predictions on the service life of the treated timber in soil contact.
I Stephan, S Göller, D Rudolph


The restricted distribution of Serpula lacrymans in Australian buildings
1989 - IRG/WP 1382
Temperature data has been gathered over a number of years, not only for flooring regions of various buildings in Melbourne, but also within roof spaces and external to the buildings. Findings are discussed in relation to the distribution of Serpula lacrymans within Australia, its restriction to certain types of building construction and its restriction to flooring regions. The subfloor spaces of badly-ventilated, masonry buildings are highlighted as being better suited than are the subfloor spaces of, for example, Japanese buildings for the activity of this fungus. Hence Serpula lacrymans is very restricted in its distribution in Australia, yet where it is active it does grow rapidly and causes rapid flooring failures.
J D Thornton


Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh


The accelerated field simulator (= fungal cellar)
1982 - IRG/WP 2170
G C Johnson, J D Thornton, H Greaves


An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong


The effect of sapwood on the rate of deterioration of fence posts
1986 - IRG/WP 1277
In order to evaluate the effect of the presence of sapwood on the rate of deterioration of fence posts, 30 specimens with and without sapwood of Eucalyptus citriodora, Eucalyptus paniculata, Eucalyptus saligna and Eucalyptus tereticornis were exposed in three test sites in the State of São Paulo, Brazil. The results of the inspection carried out in 1985, after 5 years of exposure, are reported in the present paper.
M S Cavalcante, G A C Lopez, E S F Mucci, R G Montagna


Preventive action against fungal decay: A comparative experiment on the effects of natural and artificial infection of wood by Basidiomycetes
1981 - IRG/WP 2160
M Fougerousse


A short note on fungal decay in K33-treated poles
1982 - IRG/WP 1169
Soft rot cavities and erosion of the lumen have been found in K33-treated Pinus sylvestris poles from the years 1956-66 by microscopic studies. Poor treatment quality has been proved for some of these poles. The microscopy showed an unusual pattern of attack, and pre-treatment decay is suspected but not yet proved. Sounding the poles and using the Pilodyn indicated decay, but poking did not. Quantification of the attacks was possible only by microscopic studies.
H Friis-Hansen


Evaluation of new creosote formulations after extended exposures in fungal cellar tests and field plot tests
2000 - IRG/WP 00-30228
Although creosote, or coal tar creosote, has been the choice of preservative treatment for the railroad industry since the 1920s, exuding or "bleeding" on the surface of creosote-treated products has been one incentive for further enhancements in creosote production and utility (Crawford et al., 2000). To minimize this exuding problem, laboratories such as Koppers Industries Inc., USA, and Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Chemical and Wood Technology, Melbourne, Australia, have developed changes in processing of coal tar that produce distillates with fewer contaminants. This "clean distillate" is then used to formulate "clean creosote" as a preservative. These new, unique creosote formulations are being investigated as part of a program to enhance the use of regionally important wood species in the United States. Four retention levels of each of two new creosote formulations creosote, one pigment-emulsified creosote (PEC) and one creosote formulation that meets the AWPA Standard C2-95 for P1/P13 creosote (AWPA, 1995a), were applied to two softwood species and two hardwood species. Two laboratory procedures, the soil-block and fungal cellar tests (accelerated field simulator), were used to evaluate the four creosote formulations. These procedures characterized the effectiveness of the wood preservatives. The soil-block tests were used to determine the minimum threshold level of the preservative necessary to inhibit decay by pure cultures of decay fungi. In general, the soil block tests showed there was little difference in the ability of the four creosote formulations to prevent decay at the three highest retention levels as summarized in a previous report by Crawford and DeGroot (1996). The soil-block tests will not be discussed in this report. Fungal cellar tests expose treated wood to mixtures of soil-borne fungi that promote accelerated attack. Crawford and DeGroot (1996) discussed the evaluation of the creosote formulations after 17 months of exposure in the USDA Forest Service, Forest Products Laboratory (FPL), fungal cellar. At that point in time data from the fungal cellar tests showed that softwoods are protected better than hardwoods for all four formulations of creosote tested. This report will discuss exposure of the fungal cellar stakes upto 36 months. In addition, field stake tests are being used to verify service life of the new creosote formulations in vivo. Results from accelerated tests are indicative of field performance, but the correlation between laboratory and field results is still being investigated. Field stake tests are regarded as critical, long-term evaluations that provide results most directly related to the performance of treated products in service. In this study, we report on the performance of the creosote formulations after five years of exposure in field tests.
D M Crawford, P K Lebow, R C De Groot


A direct method for testing plywood and particle boards against fungal decay
1984 - IRG/WP 2214
A method directly inspired from the French standard testing method of the resistance of particle boards against fungal decay (AFNOR N° 51.295 May 1980) is described. But in that experimentation, the infestation is localized and realized in non sterile conditions. Small blocks of Fagus sylvatica (60 x 20 x 10 mm³) used as " inoculates " are infested with basidiomycetes, in Kolle flask for 4 to 6 weeks, then tightly pressed against the middle part of the test specimens (190 x 15 x 15 mm³). The lower part of the inoculates is plunged in vermiculite kept constantly humid by water containing a selective fungicide. After twelve weeks of exposure in non sterile conditions, in a green house with constant temperature around 20°C, the test specimens are then submitted to a static bending test until fracture. The comparison of the fracture-stress between control test specimens and the specimens exposed to wood rotting basidiomycetes permits to evaluate the resistance of the studied materials against fungal decay.
L N Trong


Wood preservation in the USA
1982 - IRG/WP 3215
This report is a comprehensive survey of the status of the wood preservation field in the U.S.A. at the start of the 1980s. The importance of wood preservation is discussed and its industry described. Various statistics and analyses regarding the use of treated wood have been compiled. Both pressure and non-pressure applications have been covered, as well as remedial treatments and pest control operations. A list of American organizations concerned with wood preservation have been included, together with the various research laboratories which are studying the biodeterioration of wood and its protection. Information is given on the standards and specifications which are in current use. The report, which is fully referenced, ends by suggesting possible future trends for wood preservation in the U.S.A.
D D Nicholas, R Cockcroft


Biological and chemical observation on the early fungal colonization of TBTO treated Swedish redwood stakes
1984 - IRG/WP 3311
Data on the early fungal colonization of Swedish redwood stakes, impregnated with 1% TBT0 / 0.5% dieldrin solution, both by double vacuum impregnation and immersion processes are presented. Results of chemical analyses of wood samples from the outer 1 mm of separate painted and unpainted stakes, exposed over the same twelve month period, are also discussed.
R Hill, A H Chapman, A Samuel, K Manners, G Morton


Isolation and identification of the fungal flora in treated wood
1976 - IRG/WP 144
J F Levy


Use of the Pilodyn to assess deterioration of treated aspen waferboard after 30 months of outdoor exposure
1986 - IRG/WP 2254
Samples of preservative treated aspen waferboard exposed outdoors for 30 mo. were compared using pin penetrations of the 6 Joule Pilodyn. These results correlated well with rankings of treatment performance based on more laborious standard mechanical tests, and demonstrate the potential for use of the Pilodyn as a tool to evaluate wood composites in test exposures with minimal destruction.
E L Schmidt, M G Dietz


Laboratory culturing and decay testing with Physisporinus vitreus and Donkioporia expansa orginating from identical cooling tower environments show major differences
1996 - IRG/WP 96-10184
Both Basidiomycete fungi Physisporinus vitreus (Pers.:Fr.) P. Karst. and Donkioporia expansa (Desm.) Kotl. & Pouz. were isolated from identical cooling tower environments. Azobé heartwood (Lophira alata), a very durable tropical wood species was totally deteriorated in cooling towers in a similar way by both fungi. First attempts to culture Physisporinus vitreus in laboratory circumstances showed a need for climatic conditions with higher temperatures and higher relative humidity compared to standard conditions known for most Basidiomycete fungi. Moreover there is a supplementary need to alter the acidity of the malt-agar medium and to add a protein nitrogen source like pepton. Identical culturing conditions were supposed for the Donkioporia expansa isolate. However the alteration in acidity is not beneficial for the growth of this cooling tower fungus. High mass loss figures up to 50% were recorded for non-durable wood species inducing wood moisture contents of over 150%, but only a slight growth stimulation on azobé could be observed under laboratory conditions.
J Van Acker, M Stevens


Are fungal cellar tests really necessary?
1989 - IRG/WP 2333
During the past decade the range of methodology used to evaluate wood preservative potential has significantly expanded. At the forefront of these new tools available to the scientist·is the fungal cellar. This technique, as currently applied, involves the exposure of treated and untreated samples to conditions of moisture and temperature which ensure optimum fungal attack. By comparison data with that obtained on similar preservative systems in conventional stake tests, acceleration factors for predicting performance have been developed. This discussion paper examines the philosophy influencing the development of fungal cellar testing, and provides an alternative viewpoint.
J N R Ruddick


Targeting fungal proteinases to prevent sapstain on wood
1995 - IRG/WP 95-10097
Discoloration of wood, caused by a variety of sapstaining fungi, leads to periodic losses in the Canadian lumber export industry. Proteolytic enzymes are thought to be necessary for retrieval of nitrogen during fungal growth on wood. The major extracellular proteinase of Ophiostoma piceae, a representative sapstaining fungus, was purified to homogeneity and its inhibition pattern characterised. Classic serine proteinase inhibitors inhibited the activity of the purified proteinase in a dose-dependent manner. Several chelating agents, detergents, heavy metals and PQ-8, a currently used commercial antisapstain formulation, also caused a reduction in proteolytic activity in vitro. Selected inhibitory compounds were then tested for their effect on growth of Ophiostoma piceae in artificial media and on wood. Heavy metals and several chelators inhibited growth on media containing protein or inorganic nitrogen, suggesting that they were toxic to the fungus rather than specific to the proteinase. However, chymostatin and PQ-8 did appear to be specific proteinase inhibitors. These products caused a decrease in growth on a protein-supplemented medium which induces proteinase production, but had little effect on growth on medium containing inorganic nitrogen. Visual assessment of lodgepole pine sapwood samples inoculated with Ophiostoma piceae also identified PQ-8 as an effective inhibitor of fungal growth. Other pure chelators and serine proteinase inhibitors did not perform well on wood. While some compounds showed promise in these tests, definitive testing and commercial application are constrained by the current lack of stable, cheap, non-toxic, specific serine proteinase inhibitors.
L D Abraham, D E Bradshaw, A Byrne, P I Morris, C Breuil


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