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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


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


Estimation of service life of durable timber species by accelerated decay test and fungal cellar test
2002 - IRG/WP 02-20249
Many kinds of durable wood species for outdoor uses has been imported from all over the world to Japan. However information on the natural durability of these species is not sufficient to estimate the service life of them in the climate of Japan. Highly durable species such as Jarrh, Teak, Ipe, Ekki, Selangan batu, Red wood, Western red cedar showed no significant percent mass losses by accelerated decay test according to the JIS Z2101, but some of them are degraded during fungal cellar test for 4 years . The decay rating (0:sound to 5:totally decayed) of them after 4 years exposure was 1.0, 2.0, 0.0, 1.0, 0.0, 2.3, 5.0 respectively. This results indicated that the conventional accelerated decay test could not evaluate the natural durability of these highly durable species at all. Solid wood specimens treated with boiling water at 120? for one hour are subjected to the same JIS test, and the obtained percent mass losses of these species are 1.2, 2.9, 1.9, 3.8, 4.7, 17.5, 0.0 % by a brown rot fungus, Fomitopsis palustris, and 17.5, 14.3, 3.3, 8.2, 4.2, 0.0, 18.3 % by a white rot fungus, Trametes versicolor respectively. Pre-treatment of solid wood specimens for removal of heartwood extractives before a accelerated decay test would be an effective way to evaluate the natural durability of highly durable species in a laboratory.
K Yamamoto, I Momohara


Use of fluorescent-coupled lectins as probes for studying fungal degradation of wood
1986 - IRG/WP 1288
The ability of the fluorescent-coupled lectins wheat germ agglutin (WGA) and Concanavalin A (Con A) to react with selected Basidiomycetes, Ascomycetes, and Fungi Imperfecti was evaluated using pure cultures of 35 fungi grown on malt extract agar. WGA, which binds specifically to the n-acetylglucosamine residues found in fungal chitin, reacted with nearly all hyaline fungal structures but did not react with dematiaceous (dark) structures. Several reasons are suggested for this variation. Con A, which is specific for a-D-mannosyl and a-D-glucosyl residues, reacted with about one half of the fungi that reacted with WGA. This variation in reactivity may be useful for studying simultaneous degradation by morphologically similar fungi having different lectin specificities. The results indicate that WGA is a useful probe for studying fungal degradation by non-dematiaceous fungi particularly at the early stages of decay.
J J Morrell, R L Krahmer, L C Lin


Effect of felling time related to lunar calendar on the durability of wood and bamboo -Fungal degradation during above ground exposure test for 2 years- (Preliminary report)
2005 - IRG/WP 05-20311
Current study was carried out to know whether the felling time of trees and bamboos based on lunar calendar affects natural durability of felled wood-bamboo or not. Each of one sugi (Cryptomeria japonica) tree of 28 years old and one Moso bamboo (Phyllostachys heterocycla) of around 3 years old was cut 12 times between February and December in 2003. Six sets of sugi tree and bamboo were felled in a day during “Hassen” period and the other 6 sets of them were also felled in a nearby non-“Hassen” day. There is a belief that “Hassen” should be avoided to perform destructive works such as cutting trees. “Hassen” lasting 12 days based on lunar calendar appears 6 times every year. After felling sample trees and bamboos, these specimens were subject to outdoor exposure at above ground level for 2 years. Properties of specimens such as moisture contents, mould and fungal resistance were examined periodically for 2 years. There was no clear difference in the degree of mould growth on the surface between specimens felled in a “Hassen” day and those felled in a non-“Hassen” day in the same month. The felling seasons, however, influenced the growth of mould on the surface of wood and bamboo clearly, which has been traditionally known in many cases. Fungal degradation evaluated by visual observation and the depth of pin penetration using Pilodyn during 2 years exposure was not affected by not only “Hassen” or non-“Hassen” also seasons when tree and bamboo felled.
K Yamamoto, S Uesugi, K Kawakami


The resistance of wood coated with different solvent-borne paints against colonisation by decay fungi
2009 - IRG/WP 09-40468
This paper examines different solvent-borne paints characteristics and their decay resistance when applied on pine wood surface. It was determined by the standard ENV 839 procedure. The part of samples were subjected to accelerated ageing according to the EN 84 standard. The discussed commercial paint systems were typical stains or penetrating oil-based products, with or without biocides.
B Mazela, P Hochmańska


Development on Damage Functions of Wood Decay for Building Envelope Design
2005 - IRG/WP 05-10556
For the hygrothermal analyses of building envelope systems for insulation design, we tried a natural decay test of wetted wood specimens without any inoculation of fungi. Three principal experimental types: under steady-state conditions (Experiment A), at a cyclic water dripping under Non-steady conditions (Experiment B) and at a cyclic water dipping under-steady conditions (Experiment C), were carried out for this purpose. After these tests, each specimen was determined its longitudinal compression strength. The detection of decay was checked this standard strength value by species according to Japanese building code and its corrected value by these moisture contents. As the results of the Experiment A, some fungal growth was observed within 10 weeks at the moisture contents of levels between 30wt% and 70wt%. As the results of the Experiment B, the simulated condition of short time condensation in summer was observed fungal growth but not affected decay problems within 124 weeks. As the results of the Experiment C, the simulated condition of periodical wetting as under floor or bottom of cladding was not observed any decay.
H Suzuki, Y Kitadani, K Suzuki, A Iwamae, H Nagai


The influence of gaseous oxygen concentration on fungal growth rates, biomass production and wood decay
1998 - IRG/WP 98-10283
The effects of air and several levels of oxygen balanced with nitrogen (% oxygen (v/v) nitrogen to 100%) on growth rates, biomass production and wood decay were investigated. The best technique for measuring daily growth rates in anaerobic jars was found to be by using 40 mm petri dishes which were attached to the walls of the jars. At the end of the test period the same petri dishes were also used for determining the dry weight of the fungal mycelia. The results showed that 5% oxygen concentration was very favourable for white rot and brown rot fungi (Basidiomycetes). When oxygen levels were reduced from 1% to 0.01%, the growth rates and dry weight of these fungi were steadily decreased. On the other hand, there was a large difference between very low oxygen levels (0.01 to 1%) and other levels (5 to 21% 02). In the case of other fungi there was not a big difference on their growth rates and biomass. Observational and numerical results on Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) degradation by Coriolus versicolor, Coniophora puteana and Chaetomium globosum showed that there was a large difference in the degradation of the wood samples caused by C. puteana and C. versicolor when exposed to air and other levels of oxygen (0.25,1, 5 and 10% 02). Weight losses obtained by C. globosum as a soft rot on timber specimens in air and other oxygen levels were all in same range and below 5%. On the other hand there was a safety point at 5% 02 below which the fungus was unable to degrade beech. This point was 10% 02 for scots pine. At these points, weight losses were under 5%.
S M Kazemi, D J Dickinson, R J Murphy


Natural durability of Iranian saxual wood (Haloxylon persicum) against the fungal decay
1991 - IRG/WP 1515
Haloxylon persicum is vidly planted in the deserfic region of Iran. At the present time, in the age of 30, these small trees are ready for cutting for the different uses, specially for rural buildings. But there's any knowledge about its durability. In this study the laboratory tests were carried out in accordance to European Standard. 5 fungi were used as: Trametes versicolor, Coniophora puteana, Poria placenta, Gloeophyllum trabeum and Stereum hirsutum. The result show that the saxual wood can be classified as resistent. It has a service life of more than ten years exposed in a mediterranean climate. Therefore the use of round wood of converted wood for out side constructions such as f.ex. rural building can be recommended.
D Parsapajouh, F H Schweingruber, K Richter


Susceptibility of CCB treated wood to fungal colonization
2003 - IRG/WP 03-10492
CCB treated wood is generally resistant to all wood decay fungi. However, like CCA impregnated wood, susceptibility of CCB treated wood to copper tolerant fungi have been observed. The ability of various brown rot fungal hyphae to penetrate and overgrow the wood samples was investigated. Samples made of Norway spruce (Picea abies) were impregnated with 5 % CCB solution according to the EN 113 procedure. After conditioning, part of the samples was leached according to the EN 84 method. Small stick of unimpregnated wood (r = 1.5 mm, l = 25 mm) was inserted into a hole, bored in the center of the samples, and after that sealed with epoxy coating. Sterilized, leached and non-leached impregnated and unimpregnated specimens were exposed to two copper-tolerant (Antrodia vaillantii, Leucogyrophana pinastri) and two copper sensitive (Poria monticola, Gloeophyllum trabeum) brown rot fungi for one, two or four weeks. After exposure, the inserted wood pieces were removed from the specimens and put onto nutrient medium in petri dishes. Growth of the hyphae from those wood pieces was then visually determined. Rate of colonization by the fungi were determined by measurement of CO2 production. After that, mass losses of parallel specimens were also determined. The fastest colonization of the unimpregnated specimens was by G. trabeum (one week). On the other hand, no fungal growth could be detected on non-leached CCB impregnated specimens even after four weeks of exposure. However, significantly more intense colonization by the copper tolerant fungi were detected on the leached CCB treated samples.
F Pohleven, U Andoljsek, P Karabegovic, C Tavzes, S A Amartey, M Humar


Accelerated decay tests to investigate postulated effects of tannins on CCA efficacy in wood
1988 - IRG/WP 3497
Five groups of blocks (10 x 10 x 5 mm³) viz., Pinus patula, Pinus patula impregnated to 4% (w/w) tannin; Eucalyptus grandis, Eucalyptus grandis with natural tannins extracted; and extracted Eucalyptus grandis with tannins returned as above; were prepared. Blocks from each group were then treated to 0, 5, 10 and 15 kg/m³ CCA and challenged in four 15-week decay tests, viz., soil burial, and exposure to monocultures of Chaetomium globosum, Coriolus versicolor and Coniophora puteana. The effect of tannin on CCA efficacy was evaluated by weight losses produced. The antimicrobial effect of tannin in wood not treated with CCA was demonstrated. However, the presence of tannin did not effect CCA efficacy in wood at the preservative retentions tested, since weight losses in CCA treated Pine and Eucalypt, both with and without tannins, were similar throughout all tests.
U L Scherer, A A W Baecker


An attempt to develop a direct and reliable method for testing the preventive action of preservation treatments of wood against fungal decay
1980 - IRG/WP 2139
In wood preservation there are two classical ways for assessing the reliability of preventive treatments against wood decay: the laboratory tests in which the various parameters are evaluated independently and the field tests or service tests in which those parameters are acting together in the natural environment. One has always tried to build bridges between the two types of experiments and to establish correlations between their results, but a rather large gap is still persisting. The aim of the research which is reported was to develop a method for testing directly the preventive action against basidiomycetes decay when the treatments do not lead to a full impregnation of the wood, but only raise a barrier of limited depth. A method has been developed, testing the wood specimens (of various sizes and shapes for representing various types of end-uses) out of test vessels, i.e. in non sterile conditions, but with well checked pure cultures. The various steps of the research are exposed and the results so far obtained allow to expect some interesting possibilities of testing directly, rapidly and accurately the resistance of any wood product, in its ready to use form, to decay by basidiomycetes.
M Fougerousse


Comparison of the effects of borate, germanate and tellurate on fungal growth and wood decay
1992 - IRG/WP 92-1533
The tetra-hydroxy borate ion is known to undergo complexation with polyols and has been shown to inhibit dehydrogenase enzymes in this way. It has been previously suggested that this complexation is responsible for the inhibition of fungal growth and the protection of boron treated timber. Other ions that have the ability to complex with polyols have also been shown to inhibit dehydrogenase activity. The effect of two of these ions on fungal growth and wood decay was compared to that of borate. It was found that both germanate and tellurate could reduce fungal growth and provide protection of wood against decay at similar molar concentrations as borate. The results have been used to further develop our understanding of the mechanisms of action of borate wood preservatives and substantiate the theory that borate ion/polyol complexation is responsible for the protection of boron treated timber.
J D Lloyd, D J Dickinson


Soluble nutrient content in wood and its susceptibility to fungal discoloration and decay in above ground and ground tests
2000 - IRG/WP 00-10336
The objective of this comprehensive study was to reveal the impact of soluble nutrients in wood on its susceptibility to fungal discoloration and decay in various tests, which is important for the test methodology and standardisation. Seven tests were carried out including pure culture above and ground contact tests, above ground field test and laboratory ground contact tests. The samples containing soluble sugars and nitrogen were more susceptible to mould discoloration than those poor in nutrients. A laboratory test with the fungus Penicillium brevicompactum predicted well the moulding tendency of the samples in the consequent field test. The samples rich in nutrients showed an average of 16% of mass loss whereas samples poorer in nutrients were significantly less affected (8-9%) after 120 days of exposure in a soil rich in soft rot fungi. A pure culture test with the soft rot fungus Phialophora mutabilis confirmed the above -mentioned observation. Garden compost, rich in both soft rot fungi and bacteria, caused severe mass loss (40-48%) of the samples after 120 days of exposure, but no difference in the mass losses between the samples rich and those poor in nutrients was measured. The content of nutrients was neither related to the mass loss of samples in a soil rich in brown rot fungi, nor in a pure culture test with the brown rot fungus Postia placenta. The nutrient status of samples as well as the choice of test soil can lead to completely different results and, consequently, conclusions. The results are in favour of taking samples with approximately equal content of soluble nutrients to decrease the variability of test results, e.g., mass losses.
O M Caballero, N Terziev


Assessment of wood decay in small-scale unsterile soil-bed tests
1997 - IRG/WP 97-20111
This study is concerned with the investigation of wood decay in small-scale unsterile soil-bed tests. Tests were performed with untreated heartwood samples from five hardwood species of different natural durability classes ranging from highly perishable to very resistant. Our results confirmed the critical role of soil moisture content on wood decay. The highest decay rates were observed at moisture levels close to the soil water holding capacity (WHC). With all the wood species tested, decay was retarded in soils with lower or higher moisture contents. Modification of the soil properties by addition of different amounts of an inert porous material did not affect the extent of wood decay provided that the moisture content of the modified soils was maintained, in each case, at their respective WHC. Test performed with mini-stakes (5 x 10 x 100 mm3) and smaller mini-blocks (5 x 10 x 20 mm3) showed similar levels of decay, irregardless of the test specimen size. In both cases, high mass and modulus of elasticity losses were observed in the highly perishable to moderately durable wood species after only 12-18 weeks of exposure. Based on the extent of wood decay, the small-scale soil-bed test was found to successfully discriminate between wood species in different natural durability classes.
L Machek, A M Derksen, R Sierra-Alvarez


Statistical evaluation of 'micro-bending' samples for classification of wood attacking fungi
1992 - IRG/WP 92-1544
Micro-specimens from both hardwood and softwood were exposed to selected species of field isolated fungi. The strength reduction and weight loss caused by these fungi were determined. A statistical procedure was then developed to classify the fungi into brown-, white-rot, or non-decay fungal categories based on these data. The procedure reveals the extent of hazard a fungus poses to wood members. Using established base criteria as described herein, the procedure can be used to classify unknown field-isolated fungi to a pre-specified degree of certainty. Although this approach to fungal classification is not novel, it has not been used previously for decay classification. Implementation of similar classification procedures employing additional parameters would help to refine the approach allowing laboratories other than those specializing in fungal taxonomy to conduct accurate decay analyses on field samples.
B Goodell, Jing Liu, A Homola, J Jellison, J Shottafer


Laboratory testing of wood natural durability - In soil-bed assays
1998 - IRG/WP 98-20141
Laboratory methods for assessing wood decay resistance are being investigated in the framework of an ongoing European research project. This paper summarizes the main results obtained for soil-bed tests based on the European prestandard ENV 807-Test 2. The data suggest that this testing methodology is suitable for evaluating the natural durability of timber species in soil-contact under conditions which promote soft rot. Results after 16 weeks of exposure were found to enable the assessment of wood durability. Both, mass and strength (MOE) loss determination proved suitable for hardwood testing. In contrast, only the MOE losses recorded for softwood species were correlated with their expected decay resistance. The lack of correlation between mass loss and durability data is likely related to the very slow decay rates found for softwood timbers in the soil bed. Furthermore, artificial weathering prior to testing was shown to affect the susceptibility of some timber species to soft rot decay. This suggests that a weathering step may be required prior to biological testing. Wood leaching by the protocol described in EN 84 deserves attention as a possible alternative to the very expensive and time consuming artificial weathering pretreatment. In conclusion, laboratory soil testing using a modified ENV 807-Test 2 methodology can be recommended for assessing the durability of timbers to be used in ground contact. Such tests can provide useful information to complement the results from basidiomycete tests. The potentials of basidiomycete tests based on EN 113 to assess the natural durability of timbers were also investigated. The main findings will be presented at this conference by van Acker et al. (1998).
R Sierra-Alvarez, I Le Bayon, J K Carey, I Stephan, J Van Acker, M Grinda, G Kleist, H Militz, R-D Peek


Evaluating the resistance of wood-based panel products to fungal attack
1995 - IRG/WP 95-20071
At present there is considerable disagreement among national research institutes within Europe and panel product manufacturers on the most appropriate method of testing and indeed the need for specific biological durability testing. This paper seeks to place before a broader international audience, the issues related to development of a European standard for evaluating the resistance to fungal decay of wood-based panel products. It rehearses the particular issues which need to be addressed. In particular it identifies as problems to be resolved, pre-conditioning of test samples to remove transient leachable/volatile preservative components, choice of weight loss or strength loss as efficacy criteria, and appropriate sampling levels.
R G Lea, R W Berry


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


Fungal siderophores and their rôle in wood biodegradation
1990 - IRG/WP 1442
Iron and other metals such as manganese, play an important role in the metabolic functions of fungi that cause wood deterioration. These transition metals are also found in, or associated with, the extracellular fungal enzymes shown to be directly involved in the decay process. Recently our research group was able to show that siderophores (low molecular weight biological chelators) are produced by both brown and white rot fungi. These siderophores may function to scavenge transition metals for fungal metabolism and extracellular enzyme production. In addition, our preliminary work with the purified siderophores suggests that these compounds may play a more direct role in lignin modification, similar to that reported by other researchers investigating the properties of 'biomimetic' structures. Because of the low molecular weight of the siderophore-metal complex (500-1000 daltons), and the oxidizing potential of the bound transition metals, certain siderophore structures could also play a potential role in early stages of cellulose depolymerization by brown rot fungi. Developing a better understanding of the action of fungal siderophores, their role in scavenging metals for fungal metabolism, and their possible function directly in lignocellulose degradation, will help us to better understand how wood degradation occurs.
J Jellison, B Goodell, F Fekete, V Chandhoke


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


The influence of staining fungi on the decay resistance of wood treated with alkylammonium compounds
1984 - IRG/WP 3308
Although found to be very effective in laboratory tests, alkylammonium compounds (AAC's) have failed to perform as well in field stake tests. Examination of leachability showed that this was not the cause. The present study investigated the possibility that staining fungi, (which have been observed to rapidly infect the field stakes), degrade the AAC wood preservative. Soil-blocks were treated with alkyldimethylbenzylammonium chloride, and sterilized, using gamma radiation. Half of the blocks were exposed to a mixed suspension of staining fungi, which had previously been isolated and identified from failed dialkyldimethylammonium chloride-treated stakes. After incubation for ten weeks they were conditioned, and one half leached in a static seven day leaching cycle. Half of the blocks not exposed to the staining fungi were also leached in a similar manner. All the blocks were then sterilized prior to exposing to one of three decay fungi, Lentinus lepideus, Gloeophyllum trabeum and Poria placenta. Following the test, Lentinus lepideus was found to be least tolerant to the AAC wood preservative, while Poria placenta was the most tolerant fungus. The Poria pre-exposure of the soil blocks to staining fungi greatly increased the toxic threshold and toxic limits of AAC to both Gloeophyllum trabeum and Poria placenta. The increases were almost independent of leaching, suggesting that degradation of the AAC is taking place rather than rupture of the AAC-wood substrate bonding. The increase in the toxic threshold to ca 9 kg/m³ would clearly have caused failure of the stake material in test at Westham Island, since the maximum concentration in that test was only ca 10 kg/m³.
J N R Ruddick


International comparison of three field methods for assessing the in-ground resistance of preservative-treated and untreated wood to termites and fungal decay – Summary of observations after five years
2003 - IRG/WP 03-20261
Results are presented from a five-year study conducted in five locations in Australia, Thailand and the USA. Three methods of exposure were assessed (below-ground, graveyard and ground contact) for evaluating the in-ground termite and decay resistance of Pinus radiata D. Don sapwood stakes that had been vacuum pressure impregnated with CCA (Type C) and ACQ (Type D) each at two nominal retentions (2 and 4 kg/m3), and of outer heartwood stakes from five trees of the durable North American Baldcypress, Taxodium distichum (L.) Rich. The termite attack and fungal decay ratings, based on the loss of cross section of the stakes, declined more rapidly at the three tropical sites in southern Thailand (Phuket) and in northern Australia (Darwin) compared to the two more temperate sites in southern USA (Gulfport, Mississippi) and southern Australia (Griffith, New South Wales). Depending on the type of preservative treatment (detailed for termites only) the three different assessment methods yielded either similar trends (ACQ 2 kg/m3; baldcypress) or outcomes varied with site and method (CCA 2 kg/m3; CCA 4 kg/m3) or the three assessment methods could be ranked from most to least effective in the same sequence across all sites (ACQ 4 kg/m3). Treatments or type of timber elicited different responses from the local termite fauna (from readily contacted by termites to avoidance). These responses can be modified by the way specimens are presented to termites. Average [n = 15] termite attack ratings (1st value Australian, 2nd value ASTM rating) after 5 years in the tropics (T) and non-tropics (NT) were: CCA 2 kg/m3 T = 4.3/6, NT = 6.7/8; CCA 4 kg/m3 T =5.5/7, NT = 7.4/9; ACQ 2 kg/m3 T = 4.4/6 , NT = 6.9/9; ACQ 4 kg/m3 T = 5.4/7, NT = 7.1/9. Baldcypress was more durable in the USA and Thailand (slight attack) and least durable against Mastotermes darwiniensis Froggatt in Australia (moderate attack). Fungus decay ratings (1st value Australian, 2nd value ASTM rating) after 5 years were: CCA 2 kg/ m3 T = 5.1/7, NT = 7.9/9; CCA 4 kg/m3 T = 6.1/8. NT = 7.8/9; ACQ 2 kg/m3 T = 5.2/7, NT = 6.7/9; ACQ 4 kg/m3 T = 5.6/8, NT = 7.7/9. Baldcypress results varied with source tree and test method.
M Lenz, J W Creffield, T A Evans, B M Kard, C Vongkaluang, Y Sornnuwat, A F Preston


Effects of the specimen position on fungal colonisation and wood decay by en 113 test fungi
1998 - IRG/WP 98-20136
For testing wood preservatives according to EN 113 it is common practice to plant the test blocks on neutral supports in order to prevent (1) a diffusion of chemicals into the agar medium and (2) an excessive moistening of the specimens. The procedure was employed in EN 350-1 for testing the natural durability of solid wood. It turned out to be of problematic nature because of the individual requirements of the test fungi. A certain degree of moisture can stop the virulence of one species, but - on the other hand - favour the virulence of another, so that different ratings of durability can be expected. In order to clarify this relation, blocks of durable and non-durable wood species were planted on different support materials and directly on the mycelial mat. Coniophora puteana, Coriolus versicolor, Gloeophyllum trabeum, and Poria placenta were used as test fungi. The results reveal a wide range with respect to the rate of colonisation and decay of the respective wood species if supports or no supports are used.
G Kleist, M-T Lenz, R-D Peek


Fungal decay resistance of Rubber wood treated with heartwood extract of Rosewood
2005 - IRG/WP 05-30367
Alcoholic extract of Dalbergia latifolia heartwood was studied for its toxicity towards wood decaying fungi. Rubber wood blocks were treated with this extract to three different retention levels (0.1%, 0.2% & 0.5%) and the treated wood blocks were assessed for their resistance towards two white rot and two brown rot fungi. Treated blocks showed improved resistance over the control blocks. At 0.5% retention level, treated rubber wood blocks exposed to fungus showed a weight loss of 15% as compared to 57 % in control blocks. A positive correlation was found between fungal decay resistance and retention level of the extract.
A K Sethy, H C Nagaveni, S Mohan, K T Chandrashekar


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