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Decay resistance of wood removed from poles treated with Trichoderma
1989 - IRG/WP 1386
Wood blocks removed from a distribution pole previously treated with a biological control product (Binab FYT pellets) were exposed in soil block tests to selected basidiomycetes. The blocks were removed from regions of poles where Trichoderma colonization had been confirmed by extensive sampling and computer mapping of microbial inhabitants. The results indicate that material from pole interiors colonized by Trichoderma is able to resist decay by Lentinus lepideus and Antrodia carbonica. Any decay prevention was lost however when the wood was steam sterilized prior to exposure to the basidiomycetes. The implications of the results for the use of biological control of internal decay in creosoted poles is briefly discussed.
A Bruce, B King, T L Highley

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

Chemical, physical and biological factors affecting wood decomposition in forest soils
2003 - IRG/WP 03-20281
Organic matter (OM) decomposition is an important variable in determining the potential of forest soils to sequester atmospheric CO2. Studies using OM from a particular location gives site-specific decomposition information, but differences in OM type and quality make it difficult to compare results among soils and forest ecosystems. By using a “standard” OM in decomposition studies, OM quality is held constant, and decomposition is a function of soil abiotic (moisture, temperature, O2/CO2, redox potential, pH, N, P, etc), and biotic (microbial biomass, functional diversity) properties. Wood is a good standard material to use in soil OM decomposition studies, since it is a normal soil component (woody residue, coarse roots), and a slow decomposition rate allows wood to remain in the soil for a number of years. In 1998 a wood stake study was initiated on both public and industry land throughout the U.S., Canada, and Europe. These sites represent a variety of climatic conditions and forest types, which cover a wide range of soil chemical, physical, and biological properties. Wood stakes of two tree species are being used to contrast different lignin types present in wood: loblolly pine (Pinus taeda), and aspen (Populus tremuloides). The objectives of this study are: (1) to determine the effects of abiotic soil properties on wood decomposition, and (2) to assess how these soil properties affect microbial activity and diversity during wood decomposition. This paper will present an overview of the study protocols, field and laboratory methods used, and discuss preliminary results from several of the study sites in North America and Europe.
M Jurgensen, P Laks, D Reed, A Collins, D Page-Dumroese, D Crawford

New approaches to practical evaluation method of bio-degradation of wooden construction - Non-destructive detection of defects using radar technique
2000 - IRG/WP 00-20214
There have been a number of researches and developments on the techniques and apparatus for the nondestructive evaluation of the biological deterioration in wood and wooden constructions, such as decay or insect attack in house, public buildings or in historically important architectures. As for the detection of the decay in wood, techniques using sound in audible or in ultrasonic frequency ranges, stress waves, heat wave and X- ray have been investigated, where the changes in the physical properties expressed in the wave form were related to decay. The change in the velocity, the attenuation or the frequency spectrum of these physical energy waves can be associated with the decrease of the specific gravity or the structural change due to decay. Some mechanical properties such as the boring resistance and the elastic properties of wood surface could be an indicator of decay. The dielectric property of wood and its relation to decay is also useful. Miller et al. (1989) applied a radar technique to diagnosing of standing trees. However the techniques previously developed are not always feasible. One of the possible reasons is that these physical or mechanical properties change not only on decay but also on other factors, such as the water content or the grain direction in wood. In addition, sometimes the techniques are less practical, strictly not non- destructive or too expensive. In practical maintenance operation of wooden constructions, visual inspection together with sampling method plays an important roll, however a specialized training is needed for the operator to get the skill of the diagnosing. In this study, to establish a practical evaluation method of bio- degradation in wooden construction, scanning using a newly developed portable radar apparatus was investigated. By comparing the results with other methods, a more practical method to evaluate the bio-degradation in wood was proposed.
Y Fujii, Y Komatsu, Y Yanase, S Okumura, Y Imamura, M Tarumi, H Takiuchi, A Inai

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

Method of embedding and staining of wood after biological testing to support the identification of decay type
1998 - IRG/WP 98-20131
A method for preparing wood for microscopic analysis after decay testing is described, with special regard to a novel fast simultaneous staining, which helps to identify different types of decay. The novel staining process is explained as well as the embedding of heavily decayed samples in polyethylene glycol (PEG) and picking up of sections by transparent adhesive tape. Special feature of the introduced simultaneous staining is the utilisation of the basic methine stain Basacryl Brillant Rot BG (C.I. Basic Violet 16). It is mixed with Astrablue FM in an aqueous solution without precipitation that usually occurs when other basic stains e.g. Safranine are mixed with Astrablue. So it is possible to perform a simultaneous red-blue staining quickly and easily in a single pass. This allows, for instance, to stain hand sections of specimens in the field and to examine them with a field microscope on the spot. The method proved to be successful in microscopic examinations after biological testing in soil contact of Pinus sylvestris L. and Fagus sylvatica L. untreated and modified with melamine resins. With the aid of the staining, type and proportion of decay (brown-rot, white-rot, soft-rot and bacteria) were identified in ministakes.
A O Rapp

European standardization for wood preservation. Progress report 91-92
1992 - IRG/WP 92-2398
Since the IRG 22 conference in Kyoto, CEN/TC 38 Plenary met twice in relation with several working group meetings. 5 upon 6 of the interpretative documents have been prepared by adhoc groups of the Standing Committee for Construction within the scope of the 89/106/EEC directive on Construction Products. The expected requirements attached to wood preservation are both requirements 1) and 3): 1) mechanical resistance and stability; 3) hygiene, health and the environment. A consequence should be a redrafting of the previous official mandate delivered on September 27, 1989: - direct mandate on wood (solid and reconstituted) as well as wood preservatives as construction products - horizontal joint-mandates on wooden-commodities in relation with the other TCs in charge of such commodities. Another consequence is a formal exploration by TC 38/WG 11 "Permanence of active ingredients in treated timber" through a first couple of standards entitled "methods for measuring losses of active ingredients and other preservative ingredients from treated timber - Part 1: Laboratory method for measuring losses by evaporation to air - Part 2: Laboratory method for measuring losses into fresh water or salt water". This works anticipates the mandate and means that TC 38 is currently making progress, towards air and water quality. Apart from building activities, TC 38 got also by the end of 1991 an order of standardization on Creosote, and Creosoted-timber following the 13th adaptation of 76/169/EEC Diretive Creosote specifications. This additional event results from the trend in Brussels to develop the so-called "new approach" where the EC authorities elaborates essential requirements with mandates to CEN explicit them in close cooperation with the industry.
R Hüe

Accelerated testing for out of ground contact using natural biological preconditioning
1996 - IRG/WP 96-20088
Small blocks made of Scots pine sapwood were treated, buried in vermiculite and exposed to natural microbial colonisation during outdoor exposure prior to laboratory decay testing. Periodic microbial isolations, moisture content, permeability and weight loss tests were also conducted. Bacteria and moulds colonised the vermiculite and miniblocks well. Aureobasidium pullulans was common on TnBTO treatments. Basidiomycetes were isolated from the control miniblocks at 3 months. Controls showed slightly increased permeability compared with treated samples after 1 month. At 3 months, controls, all TnBTO treated blocks and the lower retentions of DDAC showed permeability increases. Weight loss in the field was low up to three months, even in the controls (3.5%). Agar block trials with no natural pre conditioning showed all preservative treatments were effective, but, after only 1 month's field exposure the lowest retentions no longer provided adequate protection. Further studies are in progress.
S Molnar, D J Dickinson, R J Murphy

Accelerated testing for out of ground contact using natural biological preconditioning: Part 2
1997 - IRG/WP 97-20108
Small blocks of scots pine sapwood were treated, buried in vermiculite and exposed to natural microbial colonisation during outdoor exposure prior to laboratory decay testing. An EN 84-type leach trial was carried out on unexposed samples. Periodic microbial isolations, moisture content, permeability and weight loss tests were also conducted. The experiment ran for 12 months. The colonisation of the miniblocks by micro-organisms was rapid and different patterns of colonisation were observed for differently treated miniblocks. The dominant organisms throughout were Alternaria sp., Fusarium sp., Curvularia sp., Aureobasidium pullulans, Phialophora sp. and bacteria. Weight losses of 10% occurred in the field by 12 months with untreated samples. DDAC- and TnBTO-treated miniblocks (at the recommended commercial retention) had weight losses of 7% and 8% respectively. ACQ treated samples at this retention had the lowest weight losses at only 1.5%. Of the treated samples, TnBTO-treated blocks had the most rapid rate of weight loss and also the fastest increase in permeability. TnBTO-and DDAC- treated samples had equivalent final permeabilities, at double the value of the ACQ-treated blocks. The decay trial indicated that this natural pre-exposure method was very severe with reduced performance of all treatments in the monoculture Basidiomycete tests after 12 months of pre-exposure. The comparative leaching trial showed that the failure of the preservatives was not due only to severe leaching in the test system. The white rot decay test indicated that at all retentions TnBTO- and DDAC-treated miniblocks had reached over 3% weight loss by 3 months pre-exposure but for ACQ this weight loss was not reached until 12 months. In the brown rot test at all retentions of TnBTO and ACQ weight losses of over 3% were reached by 3 months and for DDAC by 6 months.
S Molnar, D J Dickinson, R J Murphy

Melamine resins as preservatives results of biological testing
1996 - IRG/WP 96-40061
Based on previous work of the authors on resins, the upgrading of wood with a true solution of a methanol etherificated melamine resin in low aqueous concentration was performed. For the relative assessment of the biological resistance against brown and white-rot fungi were used not only untreated controls of pine sapwood (Pinus sylvestris L.), but also heartwood of European larch (Larix decidua Mill.). Even at the lowest applied concentration of 7.5% resin in the treating fluid (about 10% weight gain), the treated wood showed considerably less mass loss than heartwood of European larch. Leaching according to EN 84 resulted in no difference. The above outlined is valid for lab tests according to EN 113. First results of ongoing experiments with samples in soil contact exhibited general problems of testing modified and resin treated wood, using standard methods made for classical wood preservatives.
A O Rapp, R-D Peek

Testing biological durability of wood-plastic composites
2006 - IRG/WP 06-20347
Testing biological durability is inherently different for wood-plastic composites (WPC) compared to solid timber. However there is clearly a need for more information on the durability of WPC’s, on the effect of decay on the material properties of WPC’s and on methods for assessing decay of WPC’s. For the emerging European WPC market there has been some discussions on how to work on these topics. Laboratory testing is focussing on using the most appropriate test methods from the wood durability testing. Basidiomycete testing as was developed for wood based panels is proposed and soft rot testing can be done in accordance with laboratory methods for the evaluation of natural durability. There is however concern on the pre-leaching or pre-conditioning required to be in line with the slow water uptake of most modern wood-plastic composites. This is also of concern when dealing with field testing and probably will require out of ground contact testing with extra control of the moisture balance. It is also relevant that testing will become a requirement when dealing with the EU Directives on biocides (BPD) since many wood plastic composites contain fungicides and the one on construction (CPD) when load bearing applications are envisaged. Finally it is considered important to benchmark the WPC products concerning their biological durability with commonly used wood based products for different commodities allowing as such a better prediction of service life.
J Van Acker

Resistance of DMDHEU-treated pine wood against termite and fungi attack in field testing according to EN 252. Results after 30 months
2006 - IRG/WP 06-40354
The aim of this study was to determine the effectiveness against decay and termite attack of pine sapwood treated with pure and modified DMDHEU in a field test according to European Standard EN 252. Some of the treatments tested were able to increase, within the period of the test reported (30 months), the resistance of the wood both to micro-organisms and termites. The curing process seems to be the key factor for this increase as WPG (weight percent gain) of the modified wood alone was not sufficient for the prediction of the long-term performance.
S Schaffert, L Nunes, A Krause, H Militz

Moisture dynamics of WPC as basis for biological durability
2010 - IRG/WP 10-40520
The largest market for wood-polymer composites (WPCs) is currently decking. Although many products are commercially available, a proper standard for the assessment of the biological durability of WPC does not exist. Recommended standards for testing resistance against basidiomycetes should be completed with a method to bring the specimens in a worst case situation, obtaining a moisture level high enough to initiate and support fungal growth at the beginning of, or early in the test. In this study a simple, but efficient way to increase the moisture level of test specimens of 9 commercialized WPC decking products is presented. The 24 h air-drying period after 4 weeks immersion in warm water strongly reduced the high moisture content (MC) of the wood particles, but the induced thickness swell may allow a quicker re-moistening. Performing a fungal test with these moistened specimens, Coriolus versicolor caused 2 – 15% mass loss (ML) and Coniphora puteana 1 – 12% ML despite of the poor virulence of latter fungus. ML was correlated with the MC after incubation and the thickness swell due to the pre-treatment. The ability of fungal spores to settle on WPC surfaces was investigated as well by placing specimens in a cabinet loaded with mist saturated with fungal spores and an equivalent outdoor test setup. Linking results to the composition or production process is difficult and was not the main goal of this research, but PVC based materials clearly performed the worst: high water absorbing and thickness swell, the highest ML in lab-based fungal testing and the most distinct fungal staining during outdoor exposure.
N Defoirdt, J Van Acker, J Van den Bulcke

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

Development of procedures for sampling, testing, and classification to determine the biological durability of wood and wood products
2020 - IRG/WP 20-20676
This paper informs about a research project, which deals with several shortcomings and a lack of clarity within EN 350:2016. The project started in January 2020, will run for 3 years, and is operated by the Institute of Wood Technology Dresden (IHD) and the University of Goettingen (UGOE). Determination and classification of durability of wood and wood products against wood-destroying organisms is regulated by EN 350. By the revised version of 2016, its scope has been extended to processed wood, including heat-treated, preservative-treated and otherwise modified wood as well as wood-based materials. Neither the standard itself nor the indicated test methods allow a durability classification in a comprehensive manner. Aim of the project is to develop applicable methods for sampling and durability testing as well as an adequate classification system, enabling a comparative performance evaluation of different products. After identifying the product-specific, methodological development needs, selected products and materials from various groups will be investigated, using both laboratory and field test methods. Based on the results, a technical guideline will be compiled, which will include aspects of sampling, testing, durability classification, and recommendations for standardisation and product declaration.
W Scheiding, K Jacobs, S Bollmus, C Brischke

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

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

Proposed method for out-of-ground contact trials of exterior joinery protection systems
1981 - IRG/WP 2157
Methods for testing the efficacy of preservative treatments for exterior joinery are described using the format of a European Standard. Commercially used treatments applied to jointed test units (L-joints) which are then protected by conventional finishes are exposed to normal outdoor hazards out of ground contact. Assessment is made a) by determining eventual failure through decay and b) by destructive examination of replicate treated and untreated units, after increasing time intervals, rating comparative performance in terms of wood permeability increase and the progress of microbial colonisation.
J K Carey, D F Purslow, J G Savory

JWPA method for testing effectiveness of surface coatings with preservatives against decay fungi
1981 - IRG/WP 2164
In 1979 JWPA established a new method for testing effectiveness of surface coatings in accordance with practical use of preservative-treated lumber. Comparing the new testing method with JIS A 9302, a few new trials - size of wood specimen, weathering procedure, and decay-test procedure - are incorporated.
K Tsunoda

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

Marine testing of selected waterborne preservatives
1987 - IRG/WP 4137
In 1978 a marine test was established at West Vancouver, B C. to determine the performance of selected waterborne preservatives. The preservatives in test were chromated-copper-arsenate (CCA-C), ammoniacal copper arsenate (ACA), a modified formulation of ACA which contained a higher copper content (modified ACA), ammoniacal copper zinc arsenate (ACZA) and ammoniacal zinc arsenate (AZA). The wood species used for the test was red pine. After eight years in test the CCA is providing excellent performance at all retentions, while the modified ACA is showing significant deterioration only at the lowest level. The ACA is performing quite well although it shows signs of surface deterioration at all retention levels. The performance of the ACZA is rated as unsatisfactory at retentions below 32 kg/m³ while AZA was considered to be unsuitable for use in the marine environment.
J N R Ruddick

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

A rapid field bioassay technique with subterranean termites
1983 - IRG/WP 1188
Details are summarised of a field procedure which is designed to ensure continuous exposure to a replenishing termite biomass. After pre-baiting to determine the presence and identification of a termite hazard, test specimens (35 x 35 x 250 mm³) are installed vertically in the ground adjacent to and in contact with bait specimens of the same dimensions and interconnected by susceptible feeder strip.
C D Howick, J W Creffield

Testing of wood preservatives against marine borers (Part 1). Method of testing wood preservatives against marine borers (Part 2)
1971 - IRG/WP 37
P C Trussell, C C Walden

Improved techniques designed for evaluation of fungicides in soil for control of dry rot fungus Serpula lacrymans
1985 - IRG/WP 2238
Improved techniques provide a laboratory method for the evaluation of chemicals in soil for control of dry rot fungus Serpula lacrymans. Results with their application to three chemicals were reported. These techniques are useful to eliminate chemicals lacking the necessary toxicity and weatherbility for dry rot control when the chemicals have been applied to the soil.
M Takahashi, K Nishimoto

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