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Evaluation of teak sawdayst Tectona grandis L Fil as a potential source to obtain a natural wood preservative in Colombia
2004 - IRG/WP 04-30356
Plantation Teak (Tectona grandis L. Fil) has been tested as a possible source of natural wood preservatives due to the known excellent durability of old-growth teak wood. Field tests (ground proximity termite and above ground simulated decking exposures) were established in Colombia in April 2003 at two different test sites with different climates (Tropical Dry and Rain forest). Teak heartwood extracts were obtained using Soxhlet extraction with chloroform-methanol and methanol-ethanol as solvents, for two different mixtures at three different concentrations. Sapwood stakes of Patula pine (Pinus patula) and Globulos eucalyptus (Eucalyptus globulus) were vacuum pressure impregnated with these extracts, and control stakes were impregnated with CCA Type C and ACQ Type D at two nominal retentions (1 and 4kg/m3). The test sites have been found to be very active for both decay and termites. After only 9 months exposure termite attack has been observed from four species (Nasutitermes, Heterotermes, Triangularitermes, Velocitermes), and several basidiomycetes fungi have also been isolated from the test samples (Trametes, Schisophyllum, Poria). The results show that up to 100% of the samples have been subject to fungal attack, although in most samples only superficial trace attack has occurred in the exposure period. In contrast, termite attack has been rapid, primarily on the eucalyptus samples, which are suffering substantial degradation.
A Castillo, Y Cabrera, A F Preston, R Morris


Comparison of rates of wood decay from four different field test protocols following 4-5 years exposure at a site in New Zealand
2011 - IRG/WP 11-30565
The rate of decay of Pinus radiata was evaluated using four different field test protocols at a site near New Plymouth, New Zealand. The average Scheffer index was 86 over the five year period of testing. The field tests were an in-ground stake test (AWPA Std E7-01) and three above ground tests – lap-joint (AWPA Std E16-98), decking (AWPC protocol) and ground proximity tests (AWPA Std E18-06) Two wood preservatives were used, ACQ and an experimental formulation containing the azole propiconazole. Each preservative was tested at three retentions, a full retention or rate and then ½ and ¼ this retention. All trials included untreated Pinus radiata control samples. The most graphic differences among tests were observed in untreated samples. The in-ground stake test displayed the greatest initial rate of decay with untreated stakes failing after 2 years. However the most reliable early indicator of decay was observed in the decking test where samples were laid on untreated bearers. In a parallel decking test where samples were laid on treated bearers they remained sound for 3 years then declined rapidly in years 4 and 5. Based on untreated and preservative treated Pinus radiata the results in the present study indicate a ranking for most rapid to least rapid for above ground protocols of: decking test on untreated wood > ground proximity > lap-joint = decking on treated wood.
P Lobb, K Day, A Siraa


Wood preservatives: Field tests out of ground contact. Brief survey of principles and methodology
1976 - IRG/WP 269
This paper contains the following spots: 1.: The general need for field tests. 2.: Interests and limits of field tests in ground contact. 3.: Various methods in use for out-of-ground contact field tests. 4.: Fungal cellar tests are they an alternative to above-ground decay exposure tests? 5.: Conclusions.
M Fougerousse


In-ground performance of two formulations of chlorothalonil after five years of exposure at three test sites in Australia
1996 - IRG/WP 96-30101
Sapwood specimens of Pinus radiata D. Don and Eucalyptus regnans F. Muell. were each treated to three retentions of each of two preservative formulations (chlorothalonil in oil; chlorothalonil plus chlorpyrifos in oil) and installed in-ground at three field test sites in Australia. Specimens were treated with each formulation to achieve 3.2, 6.4 and 12.8 kg/m³ of chlorothalonil a.i. and 3.2 + 0.2, 6.4 + 0.4 and 12.8 + 0.8 kg/m³ of chlorothalonil plus chlorpyrifos a.i. For comparison, specimens of each timber species, treated to a commercial in-ground retention of a copper-chromium-arsenic (CCA) formulation, were also installed. Treated specimens (including controls) have been rated for their condition annually for attack by subterranean termites and fungal decay using a scale ranging from 4 (sound) down to 0 (failed). After five years of exposure, mean termite and decay scores for replicate test specimens at each site reveal that the performance of all three retentions of each formulation, particularly the two highest retentions, is comparable to CCA.
J W Creffield, T L Woods, N Chew


An in-ground natural durability field test of Australian timbers and exotic reference species. Part 2: Progress report after approximately 13 years' exposure
1983 - IRG/WP 1189
The condition of heartwood specimens of Australian and exotic timber species after approximately 13 years' in-ground exposure is given. Four of the 5 test sites have a termite hazard in addition to the hazard from a range of decay fungi. Values for specimen life are given only where all replicates of a timber species have become unserviceable. Results give evidence leading to doubt about the accuracy of the tentative durability ratings previously ascribed to at least some of the species under test.
J D Thornton, G C Johnson, I W Saunders


A note on testing the efficacy of wood preservatives above ground
1995 - IRG/WP 95-20078
A number of test methods have been used to evaluate the performance of wood preservatives in above ground situations. These have included EN 113 tests following natural exposure weathering (NEWT), L-joint or T-joint tests, lap-joint tests, and decking tests. A new test referred to as the A-frame test has been developed and is under evaluation. This is based on a sandwich-type test in which a thin (3.5 mm) sample is exposed outdoors between two untreated samples on a rack or A-frame. The advantages and disadvantages of these types of tests are discussed in a short note.
G R Williams, J A Drysdale, R F Fox


Biological effectiveness of ground-contact wood preservatives as determined by field exposure stake tests
1984 - IRG/WP 3297
Field exposure tests conducted on stakes treated with different creosotes, mixtures of creosote and waxy oil as well as different CCA wood preservatives over a period of 25 years, gave the following results: The CCA preservatives provided excellent biological protection to treated stakes, especially against fungal attack. The CCA Type I, currently approved for use under South African conditions is not inferior to the CCA Type II during long-term ground-contact exposure if the active elemental contents and effective retentions are taken into consideration. The creosotes provided good protection against termite attack but showed fairly poor fungal resistance during long-term ground-contact exposure under wet conditions. The addition of waxy oil greatly improved the effectiveness of creosotes against fungal attack. The CCA preservatives proved to be a better overall ground-contact preservative compared with the creosotes.
W E Conradie, A Pizzi


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


An in-ground natural durability field test of Australian timbers and exotic reference species. Part 5: Extensive data from a site where both decay and termites are active. Results from a full-replicated set of heartwood specimens from each of ten myrtaceous hardwoods after 18, 19 and 20 years' exposure - A discussion paper
1988 - IRG/WP 2324
Extensive data are presented on the decay situation, the termite situation and the decay-termite associations; all gathered from a fully-replicated set of heartwood specimens of 10 hardwood timbers after 18, 19 and 20 years' exposure in the ground at a single test site, i.e. a semi-arid steppe site. Sixteen tables are presented in addition to the one table providing the rating data; the latter representation of specimen condition being essentially all the data normally being recorded from field tests, whether these be of natural durability or preservative treated specimens. The authors give this "extra" data to show the type of information obtainable as a result of applying both mycological and entomological expertise to field assessments. Instead of discussing these results. the authors wish to generate some discussion by asking questions such as - is some of all of this information of value? - What additional/alternative information would interested scientists wish to see with respect to the most durable timbers in a test such as that examined in this report?
J D Thornton, G C Johnson, J W Creffield


A below-ground exposure method for determining the resistance of woody and non-woody materials to attack by subterranean termites
1993 - IRG/WP 93-10012
With existing field test procedures, in which specimens are installed vertically to some of their length into the ground and spaced out from each other ("grave-yard" tests), variations in the rate of contact by termites between replicates can be common. Mechanical damage to specimens during inspection and re-installation may also be difficult to avoid. A new field test method, evaluated in Australia, is described. Close to nests of or within the most active foraging sites of target species of termite, test specimens are exposed horizontally below the grownd in trenches (300 mm deep). The base of the trench is lined with strips of termite-susceptible timber. On top of the strips, specimens of susceptible timber and test specimens are layed adjacent to each other in alternating sequence. These are covered with additional strips of timber. Finally the test trench is backfilled with soil. Offering specimens together with a concentrated supply of susceptible timber below the soil surface provides an attractive food source and an environment that is conducive to sustained foraging by termites. Under Australian conditions brown, white and soft rots were present in timber specimens buried horizontally in the soil at a depth of 300 mm. The below-ground exposure method is very versatile and can be used for assessing the resistance of a wide range of materials of any shape. Inspections and re-installations of tests can be performed with ease and without causing damage to test specimens.
M Lenz, J W Creffield


Pentachlorophenol and tributyltin oxide - the performance of treated Pinus radiata after 12 years' exposure
1986 - IRG/WP 3361
Pinus radiata samples were impregnated with a range of light organic solvent preservatives and copper/chrome/arsenic salt and exposed with no surface coating both in and above ground for 12 years. Inspection of the test samples revealed that some formulations of light organic solvent preservatives will give good fungal protection and reduce splitting in Pinus radiata exposed externally without a supplementary surface coating. Tributyltin oxide performed poorly in the test compared to pentachlorophenol which gave relatively good protection under both hazard conditions. Copper/chrome/arsenic salt was clearly the most effective.
R S Johnstone


A test method to simulate above-ground exposure
1978 - IRG/WP 2112
The simulated above-ground exposure technique described is worthy of consideration as a simple procedure to determine the relative decay resistance of preservative-treated wood exposed to a moderate decay hazard. The method may readily be modified to allow testing of other materials such as plywood by simply enlarging the slots cut in the modified feeder strips. The method by no means completely simulates the conditions that exist in timbers exposed out of ground contact, nor does it simulate the natural process of infection, but it does provide lower toxic thresholds and allow reassessment of relative performance of preservatives under test conditions less severe than those of soil-contact exposures. A fully acceptable test procedure will be available only when a clear understanding is gained of the decay process in timbers and commodities exposed out of ground contact.
J A Butcher


Tropical In-Ground Durability of Structural Sarawak Hardwoods Impregnated to High Retention with CCA-salts, CCA-oxide and FCAP after 20 Years Exposure
2005 - IRG/WP 05-30384
Statistical analysis (ANOVA) was conducted on durability (termite and decay combined) rating data collected over 20 years exposure period of over 140 species of Sarawak timbers with altogether 30,000 stake specimens, at the Forest Department’s Sibu “graveyard” stake test sites from 1977. About 20 replicated stakes were pressure-treated to refusal with 10% g/ml concentration of up to 3 CCA-salt formulations and 1 CCA-oxide product and FCAP were visually evaluated every 6 months according to the 5-point ASTM D1758 durability rating scale, and the treated durability results reported in this paper are between 5 and 20 years exposure. The analysis was confined to 7 relatively high density hardwood species that are regarded suitable for in-ground structural use (ie, basic density >600 kg/m3), and had achieved a minimum preservative retention of 16 kg/m3 (as required for CCA-salts) but up to 48 kg/m3 retention. The results revealed that the in-ground durability of treated wood decreased usually after 5 years to poor-to-moderately durable levels with CCA-salts, moderate-to-high durability with CCA-oxide, but failed with FCAP after 20 years. CCA-oxide treated hardwoods out-perform the CCA-salt treated counterparts despite their relatively similar retention and “over-treatment factor”. The non-leach-resistant FCAP is clearly unsuitable as an industrial used in-ground wood protectant.
Wang Choon Ling, A H H Wong


Dominant genera of fungi isolated from the surfaces of Sugi (Cryptomeria japonica D. Don) heartwood lumbers exposed at six test sites from northern to southern regions of Japanese islands
1999 - IRG/WP 99-10304
The surfaces of wood materials are disintegrated not only by sunlight and rainwater but also by microbes when exposed above ground condition. This paper deals with the investigation of fungi isolated from the surfaces of Sugi heartwood lumbers (W100 by T10 by L300 mm) exposed at an angle of 45° without ground contact for 16 months at the six test sites from northern to southern regions of Japan. The parasites were collected from the surface using the Sellotape. Isolation medium used was PDA including 100 ppm tetracycline-hydrochloride to suppress the growth of bacteria. Identifications were microscopically conducted using a slide culture technique. Dominant genera isolated were Aureobasidium and Nigrospora regardless of the test site as well as climatic condition.
S Doi, M Mori, M Kiguchi, Y Imamura, M Hasegawa, S Morita, S Nakamra, Y Kadegaru


The ground proximity decay test method
2000 - IRG/WP 00-20205
A decay field test method, which has been recently proposed for the standardization by the AWPA, is described for evaluating the relative performance of wood samples in a severe above ground situation exposed to the weather. Data is presented on the relative performance of untreated control samples and standard preservative systems exposed at the same site at different time periods, or at different test sites with the same test materials using this test methodology. Comparison data including this method with other standardized test methods is also included. The experimental data collected during last 13 years show that the method provides a viable and consistent methodology for generating results representing the worst above ground exposed situation that might be encountered during service.
A F Preston, P J Walcheski, K J Archer, A R Zahora, L Jin


Leaching of Copper from ACQ treated wood exposed above ground
2004 - IRG/WP 04-50219
The leaching of chemicals of ACQ Type C treated wood exposed above ground for 16 months was studied. Commercially treated Hem-fir boards (Tsuga heterophylla Raf. and Amabilis fir Forb) of 37.5 mm by 87.5 mm were used. The amounts of chemical leached monthly by the rainfall were determined and the leachate was collected and analyzed. Also, the environmental factors influencing the leaching were studied. The results showed that the first four months of exposure caused the greatest loss of copper (ranged 296.12 mg/m² - 593.37 mg/m²). From the fifth month onwards, the amount of copper leached begins to decrease. After 16 month of exposure, the percentage of copper leached was 3.95% from the weight uptake and 4.96% from the volume treated. The environmental factors influencing the leaching were time of exposure, volume of leachate collected, sun hours and temperature.
P A Chung, J N R Ruddick


Tropical In-Ground Durability of CCB-treated Keruing and other Structural Sarawak Timbers after 8 – 10 Years Exposure
2007 - IRG/WP 07-30439
The heartwood of 12 mainly low-durability native timber species of Sarawak [4 Dipterocarpus (Keruing) species, Anisoptera grossivenia (Mersawa kunyit), Canarium apertum (Seladah), Dacryodes incurvata (Seladah laut), Dryobalanops oblongifolia (Kapur kelansau), Mesua macrantha (Mergasing), Podocarpus micropedunculatus (Kayu cina), Shorea compressa (Engkabang langgai), and Pterospermum javanicum (Bayur)] from various treatability classes, were pressure treated to refusal in 10% CCB preservative solution. Twenty replicated heartwood stakes of 19 x 19 x 457 (long) mm were planted to a depth of 230 mm in the ground and evaluated after the first 8 – 10 years exposure while the test continues. The field test site had high clay content, and despite the high annual rainfall (>3000 mm), samples with CCB dry salt retention of over 30 kg/m3 still remained sound after exposure (using an ASTM1758 10-point rating scale) period of up to 10 years, stakes with retention <25 kg/m3 had trace (rating: 9) or moderate (rating: 7) decay and termite attacks, while those with subsequently lower retentions failed within the first 6 years. Within an 8 – 10 years exposure evaluated at 6 monthly intervals, many stakes with only trace (rating: 9) or moderate (rating: 7) decay in the previous 6 months failed (rating: 0) abruptly within the next 6 months of evaluation instead of showing progressively severe biodegradation (i.e. ratings 4 or 7). Overall this first update of the field trial suggests for particular treatable structural species, CCB treated timbers exposed to ground contact (particularly wet clayey soils) could have a service life of at least 10 years when adequately treated to least 300 litre/m3 to achieve at least 30 kg/m3 retention.
A H H Wong, Ling Wang Choon


Performance of softwood preservative treated stakes after 4 years exposure in-ground to decay fungi and termites in tropical Australia
2008 - IRG/WP 08-10643
This field study was based on the 1993 IUFRO method and designed as a graveyard (in-ground) test in the tropical region of the Northern Territory to examine the efficacy of novel preservative formulations developed as alternative protection for softwood timber against decay fungi and termites for Hazard Class 3 and 4. This study was supported by the Forest and Wood Products Research and Development Corporation (FWPRDC). Timber specimens 500 (longitudinal) x 50 (tangential) x 25 (radial) mm were cut from the sapwood of fast grown Pinus radiata D. Don and treated with trimethylborate (TMB), sodium octoborate, linseed oil and fipronil in various solvents (toluene, linseed oil and deionised water) using a vacuum/pressure treatment method. After 4 years in-ground, the solvent control and fipronil (only) treated stakes were slightly attacked by soft rot, brown rot and white rot fungi. Most of the stakes had surface damage only, while few of the solvent controls had severe damage by only decay fungi. There was slight attack on the treated timber by soft rot fungi. A small number of solvent controls and borate treated stakes were severely attacked by subterranean termites, particularly Coptotermes acinaciformis (Froggatt). The fipronil only or fipronil with borate treated stakes were not attacked.
B M Ahmed (Shiday), J R J French, S R Przewloka, P Vinden, J A Hann, P Blackwell


Evaluation of fungal infestation and decay in a simulated use class 3 situation (block test) after some years of exposure
2012 - IRG/WP 12-20487
The so named “block test” was designed as part of the assessment methodology for testing the behaviour of natural and modified wood used under use class 3 (EN 335-2) conditions. The test was developed to expose the wood close to the ground to an environment with high humidity and high biological activity, but not in soil contact. The present study describes the evaluation of fungal infestation and decay of untreated samples in different blocks depending on their exposure time, positioning within the block and wood species. After 4 years outside exposure samples showed visible signs of decay. The highest rate of decay was visible in the middle layers of the block. After 7 and 8 years outside exposure, samples of all layers were infested with a similar intensity of different types of decay. The results have shown that in the bottom layer close to ground the major type of decay is white rot as well as white rot in combination with soft rot. In contrast, samples from the middle layers and top layer were infested mainly by brown and white rot but also soft rot was observed. The test setup is according the definition of use classes a method for use class 3 applications because the samples are out of ground contact. But the infestation of samples in all layers by soft rot indicated that under use class 3 test conditions but with elevated moisture conditions soft rot attack can occur and should make part of a proper test design.
A Gellerich, K Röhl, S Adamopoulos, H Militz


Progress report on co-operative research project on L-joint testing
1983 - IRG/WP 2192
A F Bravery, D J Dickinson, M Fougerousse


A comparison of soft rot, white rot and brown rot in CCA, CCP, CCF, CCB, TCMTB and benzalkonium chloride treated Pinus radiata IUFRO stakes, after 9-15 years exposure at five test sites in New Zealand
1991 - IRG/WP 1485
The aim of this study was to determine if decay type varies significantly between five field trial test sites of different soil type, aspect and climate in 9-15 year old, replicate CCA, CCF, CCP. CCB, TCMTB and AAC treated IUFRO stakes. A visual on-site assessment of decay type on every test stake was made and observations confirmed by microscopical examination. Regression analyses were used to determine significant differences of percentage frequency of occurrence of each rot type between sites and preservatives. Large differences in percentage frequency of occurrence of rot type were evident between sites. One site was dominated by brown rot (85%) and two were dominated by soft rot (99 and 91%). The fourth site had intermediate proportions of brown rot (40%) and soft rot (71%) but had the second highest occurrence of white rot (32%) (highest = 37%; lowest = 11%). The fifth site was distinct in that a large proportion of stakes (69%) had both well established brown rot and soft rot. Stakes at the other four sites tended to have only one rot type. Some highly significant preservative effects were also found. Possible causes of these differences are discussed in terms of inter-site soil type, climate and other differences.
R N Wakeling


How to Document the Performance of Super-Critical Treated Wood in above Ground Situations?
2005 - IRG/WP 05-20316
The paper presents practical experiences from the preparation of a new preservative treated wood product for introduction to the market. The product in question is Superwood™, which is treated with organic biocides using CO2 in a supercritical state as a solvent. The question is how to evaluate the performance of a new product such as Superwood™ in order to get an acceptance on the market and fulfil the formal requirements. In the European Union countries, the EN 599-1 is the standard that needs to be complied when approving a new product for the market, but it only focuses on the toxic limit against representative decay fungi according to EN 113. However, decay test, above ground and other forms of field tests are optional, this is not in line with the traditional test philosophy in the Scandinavian countries. The open question is to which extent treatment to the level of the toxic threshold value also ensures a long service life and expected performance of the treated commodity. Superwood™ is evaluated using a strategy, in which basic laboratory tests are done to get the toxic value (according to EN 599-1) and in addition a number of field tests are done including accelerated testing in the tropics. These tests are focussed on the evaluation of the performance criteria such as durability and service life and maintenance requirements. These questions must be answered by the producer without having a full record of performance test for their new products. A short status on the test performed on super-critical treated wood (Superwood™) is presented. Based on a comparison between field test in Scandinavia and in the tropical Malaysia a service life of more than 25 years for a specific supercritical treated product is estimated. It is stated that the existing European standardisation system is insufficient when it comes to service life prediction. A number of important questions need to be addressed by the European standardisation system as soon as possible because the market and the public opinion change quickly due to environmental concern.
N Morsing, A H H Wong, F Imsgard, O Henriksen


Field tests out of ground contact in France: Definition of the test procedure and preliminary results after 18 months
1981 - IRG/WP 2161
M Fougerousse


Wood furfurylation process and properties of furfurylated wood
2004 - IRG/WP 04-40289
The first processes for “furfurylation” of wood (wood modification with furfuryl alcohol) were developed several decades ago. Furfuryl alcohol is a renewable chemical since it is derived from furfural, which is produced from hydrolysed biomass waste. Over the last decade modernised processes for furfurylation of wood have been developed. These new processes are based on new catalytic systems and process additives. Two main processes for production of furfurylated wood have been developed for WPT (Wood Polymer Technology ASA) by the authors – Kebony&#61652; 100 for high modification levels of hardwoods and VisorWood&#61652; for lower modification levels of pine. Commercial production according to the Kebony process has been running since August 2000, mainly for flooring. A small Kebony production plant is now in operation in Lithuania. A larger Kebony/VisorWood production plant started up in September 2003 in Porsgrunn, Norway. Several new plants operating according to the VisorWood process, each with an annual capacity of 10 000 m³ or more, are under construction. The properties of furfurylated wood depend on the retention of grafted/polymerised furfuryl alcohol (PFA) in the wood. At high modification levels (high retention of PFA) the enhancement of a wide variety of properties are achieved: an exceptional hardness increase, exceptional resistance to microbial decay and insect attack, high resistance to chemical degradation, increase in MOR & MOE, and high dimensional stability. At lower modification levels many property enhancements also occur, however to slightly lower extent. Notable are resistance to microbial decay and insect attack, increase in MOR & MOE, and relatively high dimensional stability.
M Westin, S Lande, M Schneider


Durability of pine modified by 9 different methods
2004 - IRG/WP 04-40288
The decay resistance was studied for pine modified by nine methods of wood modification: 1) Acetylation, 2) Treatment with methylated melamine resin (MMF), 3) Acetylation followed by post-treatment with MMF-resin, 4) Thermal modification, 5) Furfurylation, 6) Maleoylation (using water solution of MG or ethanol solution of maleic anhydride), 7) Succinylation, 8) NMA-modification and 9) modification with reactive linseed oil derivative (UZA), Wood blocks of Scots pine (Pinus sylvestris L.) sapwood were modified in pilot plants. Methods 1-5 were performed by the authors at Chalmers University of Technology or at BFH in Hamburg. Methods 5-9 were part of a European research project (the Chemowood project, FAIR-CT97-3187) and therefore each of these modifications was performed by the project participant responsible for the method. For laboratory testing in TMCs (modified European standard ENV 807) and pure basidiomycete culture bioassays, smaller test specimens were cut from the modified wood blocks. Most of the modification methods were applied on test specimens for marine field testing (EN 275) and some methods to produce mini-stakes for field tests in five Swedish fields. Some modification methods result in modified wood with poor durability, whereas other methods (acetylation, furfurylation and MMF-treatment) seem to provide excellent resistance to microbial decay.
M Westin, A O Rapp, T Nilsson


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