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Results of chemical analyses in the field of wood preservation in the Bundesanstalt für Materialprüfung
1973 - IRG/WP 321
The results of qualitative and quantitative chemical analyses of wood preservatives are often the basis for evaluating the various works in the field of wood preservation. In the past 10 to 15 years a number of such works was carried out in the Bundesanstalt fur Materialprüfung, Berlin-Dahlem, dealing with the identification and effectiveness of wood preservatives and with methods of wood preservation. Fundamental realisations were made which will be summarised below. It seems advisable to differentiate between inorganic and organic chemical wood preservatives and methods of analyses. These are two distinct fields which differ also with regard to the analytical techniques applied.
H J Petrowitz


Electron microscopic detection and chemical analysis of three-lamellar structures in wood-destroying fungi
1984 - IRG/WP 1240
In the course of transmission electron microscopical investigations of pine wood decay by various brown- and white-rot fungi extracellular three-lamellar structures (TLS) formed by the fungi were found in specimens stained with ruthenium red. These structures occured in the lumen of the wood cell surrounding the hypha at the outermost layer of the fungal cell wall. In the course of the investigations these structures were also detected in fungi cultivated with glucose on a rotary shaker, where they showed forms similar to tubuli and vesicles. The three-lamellar structures formed by the white-rot fungus Sporotrichum pulverulentum, which were contained in the outermost cell wall layer, were isolated by disintegration of the fungal pellet and subsequent digestion of the fungal cell wall by snail enzyme. It was found that these structures are resistant to the enzymatic digestion and are composed of 80 to 90% carbohydrates, mainly consisting of glucose monomeres, 5 to 10% proteins, containing 5 fractions with molecular weights between 30000 and 200000, and finally 5 to 10% lipids which do not contain any phospholipid.
R Foisner, K Messner, H Stachelberger, M Röhr


Chemical analysis of TnBTO in lap-joints
1999 - IRG/WP 99-20173
This research was performed as part of the EU project FACT (contract SMT4-CT96-2135) on field tests out of ground contact and ageing methods. The results reported here are part of the work on the experimental lap-joint standard (ENV 12037). TNO investigated the TBTO content of 32 lap-joints by analysing the tin content of 90 samples. The lap-joints were treated with two different TBTO-concentrations (0.5%; 1.0%) and different treatment methods (brushing, dipping, vac-vac treatment). Analysis took place after initial treatment and 6 months after field testing above ground at the test site at Delft, The Netherlands. The samples for analysis were taken from the top layer (first 3 mm) and from the inner part of the lap-joint. Preliminary tests with different extraction methods (AWPA, CTBA and DPI-FS) for tin analysis in wood showed the highest recovery rates for the AWPA method. Therefore extraction of the wood samples was carried out in accordance to the AWPA-A6-89-4 method. The extracts were analysed by ICP-AES. Results of the tin analysis are discussed referring to theoretical TBTO concentration, treatment method and sample origin.
A Voss, P Esser, W L D Suitela


Chemical analysis for TBTN in LOSP-treated wood and preservative fluids
1994 - IRG/WP 94-20027
Tributyltin napthenate (TBTN) is being substituted for tributyltin oxide (TBTO) in LOSP preservative formulations because its lower reactivity/better stability allows co-formulation with synthetic pyrethroids. Better stability may reduce molecular degradation both in-service and during analysis. It was considered necessary to check whether TBTO analysis methods were suitable for use on TBTN treated wood. Five analytical methods for TBTO in wood were applied to TBTN-treated pine sapwood, and evaluated for recovery, accuracy and precision. It was found that treated wood could be oven-dried before analysis, eliminating the need to run parallel moisture content determinations. The best performing method involved extraction of TBTN from oven-dry treated wood with acidified ethanol followed by AAS determination of tin. Performance was checked on freshly-treated and aged material.
D P Wraight, M J Kennedy


Chemical Analysis of Southern Pine Pole Stubs Thirty-Nine Months Following Treatment with Three Methylisothiocyanate-Based Fumigants
2004 - IRG/WP 04-30349
Agricultural fumigants have been commercially used in the United States for over 20 years to control internal decay in utility poles and other wooden structures. Of the four fumigants which are currently used in the remedial treatment of utility poles, three are based on methylisothiocyanate (MITC) as being the principal fungitoxic component. Two of these MITC-based fumigants, liquid metham sodium and granular dazomet, chemically decompose within a utility pole to release methylisothiocyanate. The third MITC-based fumigant consists of 97% methylisothiocyanate in a solid melt form. Laboratory and field studies conducted as part of the Cooperative Pole Research Program at Oregon State University have demonstrated the efficacy of all three MITC-based fumigants. However, studies conducted to date have not evaluated the three fumigants under the same experimental conditions. As a result, a field study of the three commercial MITC-based fumigants was established in June, 2000 in southern pine utility pole sections. At the second inspection conducted 39 months following fumigant treatment, chemical assay borings were removed at various pole heights and depths and analyzed for concentrations of MITC using GCMS. The 39 month results showed that MITC concentrations were greatest at all pole heights and core depths in the pole stubs treated with the 97% MITC product. In addition, similar concentrations of MITC were found in the metham sodium and dazomet treated pole stubs. When compared to the corresponding chemical assay results at 13 months following fumigant treatment, the 39 month results showed a sharp increase in concentrations of MITC in the 97% MITC treated pole stubs and a sharp decrease in MITC concentrations in the metham sodium treated pole stubs. MITC concentrations remained relatively unchanged in the dazomet treated pole stubs from 13 to 39 months following fumigant treatment. When compared to a MITC threshold value for decay fungi proposed by Oregon State University, the chemical assay results at 39 months indicated all three fumigants are effectively protecting the zone of fumigant treatment (15.2 cm below to 15.2 cm above groundline) of southern pine pole stubs. However, the greatest protection within and above the zone of treatment was provided by the 97% MITC treatment. Future sampling and chemical analysis of the southern pine pole stubs are planned to monitor long term efficacy of the fumigant treatments.
R J Ziobro, J Fomenko, D J Herdman, J Guzzetta, T Pope


The chemical analysis and biological evaluation of wood extractives as potential timber preservatives
1995 - IRG/WP 95-30090
Work involved the biological performance of water and organic solvent soluble extractives of four naturally durable wood species, namely; Matumi, Tamboti, Sneezewood and the Turpentine tree. These timber species are known to be naturally durable against termites and fungi (±25 to 35 years). The extractives were evaluated against termites and fungi using impregnated pine pencil stakes in field tests and soil burial trials over a 2 year period. C13NMR analysis of extractives isolated from the wood was carried out to try and identify the key chemical components which might impart durability with a view to prediction of new potential wood preservative formulations.
P Turner, D Conradie


Microscopical analysis of formaldehyde-acid modified wood
1981 - IRG/WP 3182
Cross-linking of wood with gaseous formaldehyde improves its hygroscopic and dimensional behaviour, and its resistance against micro-organisms. However, formaldehyde cross-linking reactions take place only in the presence of an acid catalyst, which results in losses in mechanical By optimization of a formaldehyde-sulfur dioxide vapour phase process the reaction conditions were established to limit losses in modulus of elasticity and bending strength to a few percent. Under these circumstances, impact strength losses of about 50 to 75% were still noted. The reaction of formaldehyde with cellulose has been studied intensively in textile research. However little is known on the fundamental aspects of the interaction of formaldehyde with lignin and wood. In order to get further insight into the effects of a formaldehyde-acid catalyzed reaction on the technological properties of wood a fundamental analysis of the interactions of both compounds with wood has been carried out.
M Stevens, N Parameswaran


The remaining concentration of inorganic wood preservative components in EN 252 stakes after ground contact
2000 - IRG/WP 00-50159
In order to determine the biological efficiency and the remaining concentration of different inorganic and organic active ingredients during service, EN 252 specimens were impregnated with 3 copper based wood preservatives. The stakes were installed in the test field of the DESOWAG GmbH, Rheinberg, for at least 7 years. At the end of the field test some of these stakes were divided into 10 uniform segments. Afterwards each segment was milled and mixed to guarantee a nearly homogenous sample. After further sample preparation like an acidic digestion the remaining concentration of the inorganic components copper, zinc, boron and fluoride were measured by means of AAS, ICP and an ion selective electrode. Concerning the remaining concentration the following ranking of the investigated active ingredients could be deduced: Cr (90%)> Zn (60%)> Cu (40-70%) >= F (40%) > B (concentration <10%). Furthermore the results show that the remaining content of copper differs depending on the wood preservative used. The lowest content was detected for the CCZnF-formulation, the highest for the copper-quat-preservative. Furthermore it is obvious that the rate of biological decay correspond well with the distribution of the wood preservative components in the segments.
E Melcher, H-W Wegen


The identification of organic compounds in wood using thermal desorption GC-MS - possibilities and limitations
2001 - IRG/WP 01-20224
There is a clear need for the analytical characterisation and identification of organic compounds and their derivatives in different phases especially in timber. In this context the paper describes a rapid and powerful gas chromatographic method for the determination of insecticides, biocides and "other" organic substances in treated and/or modified wood. The main advantage of this procedure is that wooden material can be analysed directly without any further sample preparation. In principle the technical equipment using a mass selective detector is suitable for identifying as well as quantifying thermal desorbable compounds in only one analytical run. The main emphasis of this contribution, however, is to show the possibilities and limitations of this technique.
P Jüngel, E Melcher


The Effect on Biological and Moisture Resistance of Epichlorohydrin Chemically Modified Wood
2002 - IRG/WP 02-40224
Southern pine solid wood and fiber were chemically modified with epichlorohydrin to help in understanding the role of moisture in the mechanism of biological effectiveness of chemically modified wood. The solid wood had weight gains from 11% to 34%, while the fiber had weight gains from 9% to 75%. After modification, part of the specimens were water leached for 2 weeks or extracted for 2 hours with a toluene:ethanol (2:1) solution. The equilibrium moisture content (EMC) at 30%, 65%, and 90% relative humidity (RH) and 27 °C was determined on all specimens. Laboratory soil block decay testing using the brown-rot fungus Gloeophyllum trabeum was performed and weight loss calculated. Results show that epichlorohydrin modified specimens did not lower the EMC significantly, yet there was biological effectiveness at 31% weight gain for the solid wood and 60% weight gain for the fiber. This indicates that the mechanism of efficacy may be due to substrate modification rather than moisture exclusion. Energy dispersive x-ray analysis (EDXA) was performed locating the chlorine throughout the wood cell wall.
R E Ibach, B-G Lee


Controlled envelope treatments of Pinus sapwood, achieved by modifications to impregnation process and carrier solvents
2003 - IRG/WP 03-40258
Specimens of slash pine or radiata pine were treated to a target retention of 0.02% m/m permethrin with conventional light organic solvent fluids or with oil-modified fluids (Tanalith® T). Best achievable envelopes from LOSP fluids were poorly controlled, penetrating not only the target outer 0-5 mm zone (mean 0.019%, RSD 28%), but also breaking through into the 5-10 mm zone (mean 0.013%, RSD 37%) and further into the >10 mm zone (mean 0.011%, RSD 52%). With the oil-modified fluids, the target 0-5 mm zone received a mean retention of 0.024% (RSD 30%), with 0.003% (RSD 44%) in the 5-10 mm zone and <0.002% the >10 mm zone. This tight control of toxicant distribution facilitates economical termite control.
M J Kennedy, P R S Cobham


Silafluofen: Novel chemistry and versatility for termite control
1995 - IRG/WP 95-30069
A novel silicon - containing insectizide, HOE 084498 (&apos;Silafluofen&apos;), with a favourable toxicological profile, has shown activity against a broad spectrum of agricultural and environmental health pests. Results from laboratory and field studies around the world have demonstrated that silafluofen is effective at protecting timber from attack by various species of termite and wood-boring beetle. As a termiticide, silafluofen, applied as a dust-toxicant, may suppress/eliminate Coptotermes sp. Ongoing field trials in France, in cooperation with CTBA, indicate that silafluofen, injected directly into masonry, has controlled Reticulitermes santonensis. No signs of termite activity have been observed in the treated part of an infested house since the application was made, 2 years ago.
A J Adams, A Jermannaud, M-M Serment


Chemical Analysis of Southern Pine Pole Stubs Thirteen Months Following Treatment with Three Methylisothiocyanate Based Commercial Fumigants
2002 - IRG/WP 02-30294
Agricultural fumigants have been commercially used in the United States for over 20 years to control internal decay in utility poles and other wooden structures. Of the four fumigants which are currently used in the remedial treatment of utility poles, three are based on methylisothiocyanate (MITC) as being the principal fungitoxic component. Two of these MITC based fumigants, liquid metham sodium and granular dazomet, chemically decompose within a utility pole to release methylisothiocyanate. The third MITC based fumigant consists of 97% methylisothiocyanate in a solid melt form. Laboratory and field studies conducted as part of the Cooperative Pole Research Program at Oregon State University have demonstrated the efficacy of all three MITC based fumigants. However, studies conducted to date have not evaluated the three fumigants under the same experimental conditions. As a result, a field study of the three commercial MITC based fumigants was established in June, 2000 in pentachlorophenol treated southern pine utility pole sections. At the first inspection conducted 13 months following fumigant treatment, chemical assay borings were removed at various pole heights and depths and analyzed for concentrations of MITC using GCMS. The 13 month results showed the concentrations of MITC were greatest at all pole heights and core depths in the pole stubs treated with the 97% MITC product. In addition, higher concentrations of MITC were found in the metham sodium versus dazomet treated pole stubs. The results of the initial sampling of the southern pine pole stubs are compared to results of the fumigant efficacy studies conducted at Oregon State University. In addition, the chemical assay results are compared to a proposed MITC threshold value based on the results of the Oregon State University fumigant studies. Future sampling and chemical analysis of the southern pine pole stubs are planned.
R J Ziobro, T C Anderson, D J Herdman, J Guzzetta, T Pope


Chemical analysis of wood waste - The problem of sampling
1999 - IRG/WP 99-20168
A quantitative analysis of the content of active substances in wood is often demanded in quality control after processing and for the proper waste management. As a measure for quality control, analysis has the advantage that the type of preservative is known and assumptions can be made about its distribution in the treated wood.W aste wood may have been treated by a wide range of organic and inorganic preservatives. Therefore, differing methods of analysis have to be used. A correct sampling, however, is a problem due to the very inhomogeneous distribution of preservatives in treated wood influenced by the structure and composition of wood, type and composition of wood preservatives and their application to impregnated wood. the kind of sampling. As a result of literature investigation and own research, an overview over the influencing parameters, structure and composition of wood, type and composition of wood preservatives and their application to impregnated wood. Furthermore, secondary changes due to leaching, evaporation and ageing of active ingredients during service might contribute to an even more uneven distribution. Thus, analytical results can deviate extremely depending on the kind of sampling carried out. The smaller the sample the higher the deviations. Due to this, the applicability of techniques based on small samples, which is characteristic for rapid analysis, is restricted. Multiple data are available on distribution and ist alteration. As a result of a literature survey as well as own research, a summarising overview of the influencing parameters and their effects will be provided. It therefore does not seem practical to implement a general method of sampling. The sampling depends rather on the questions being asked by the investigation and, abover all, on the material under investigation.
A Peylo, R-D Peek


Chemical Analysis in Production Quality Control at Wood Treatment Plants
2008 - IRG/WP 08-20396
Analysis methods for quality control analysis in wood treatment plants have evolved with the changes in treatment preservative chemistries and analytical instrument technology. The basic hydrometer specific gravity measurements used for solution strength and classic wet chemistry methods for wood have given way to instrumental techniques such as X-ray fluorescence, automatic titrator, and HPLC. Not all of methods involve complex instrumentation, simple turbidimeters and handheld refractometers can be used for rapid solution strength testing. These newer methods are discussed in the paper as well as the increased importance of inspection and auditing of the treatment plants production by the chemical suppliers and third party inspection agencies.
P Walcheski, L Jin


Comparative investigations between thermal and microwave assisted digestion as a novel tool for the chemical analysis of inorganic wood preservative components
2011 - IRG/WP 11-20461
The correct chemical impregnation of wood requires an internal as well as external quality control of the treated wood. The active is located in a solid matrix, therefore it is often difficult to analyse such material since most analytical procedures are based on liquid systems. Because of this quite a number of methods – like extraction or thermal digestion - were developed in order to transfer the active to a suitable solvent, some of which are standardised. However, due to technical progress, continuously new analytical equipment is developed. This raises the question: How does this new tool practically compare to well established procedures? In order to introduce the method ‘microwave assisted digestion’ first systematic research was carried out, in which laboratory impregnated samples as well as samples from commercial practice were used. These results were compared with data obtained by means of a thermal digestion standard procedure (DIN 52161-7). In addition of these results a short economic overview comparing the costs of both techniques will be provided.
H Ahl, J Fromm, E Melcher


Slice - Cut and Analyze Laser Microdissection (LMD): A method to produce sample material from modified wood for chemical quality analysis
2011 - IRG/WP 11-20478
Wood modification with its various systems is an established way to enhance a wood products’ service life in outdoor applications. Per definition, selected material properties are enhanced by means of modification without producing toxic substances or residues during service life and combustion afterwards. The systems of impregnation modification include a physical and often chemical alteration of the cell wall by impregnation and a following polymerization of a monomer. As a result of evenly distributed modification agents within the wooden matrix, modified wood species show enhanced wood properties in all areas of the wooden sample. However, wood properties can vary within a wood sample due to an uneven distribution or polymerization of the modification agent. Laser microdissection (LMD) is a method for production of sample material for chemical quality analysis and was tested in this study. Untreated and furfurylated Scots pine (Pinus sylvestris) sapwood material was processed with a razorblade and LMD each. The chemical composition of untreated and furfurylated Scots pine sapwood latewood areas was analyzed by means of thermogravimetric analysis. Sample material was produced both with a razor blade and with LMD. As a control, the chemical composition of untreated and furfurylated Scots pine sapwood was analyzed with TGA. Sample material from whole microtome slides as well as earlywood and latewood fractions separated with a razor blade were used. With LMD sample material from selected areas was possible to prepare. The method though was very time consuming and a minimum amount of 0.5-1 mg of sample material is necessary to obtain data in necessary accuracy. This method is only reasonable for analysing specific problems as exactly selected areas within a tissue can be collected and analyzed afterwards. During the sample preparation, a chemical alteration of the chemical properties occurred. Further research is necessary to verify laser microdissection as a method to prepare sample material for chemical analysis.
K Zimmer, E Larnøy, A Treu, M Fongen


Chemical Analysis of Hydrothermally Treated Beech Wood in Buffered Mediums
2012 - IRG/WP 12-40604
Hydrothermal treatment of beech wood in buffered mediums was carried out to study the effect of different mediums of heat treatment on crystallinity index of treated specimens due to degradation of carbohydrates. Different mediums (water, buffer5, 7 and 8) and temperatures (160 and 180 °C) were used. ATR spectra focusing on indexes of carbohydrates degradation obtained and analyzed. Results showed that crystallinity index of cellulose in specimens treated in water and buffer 5 were increased in both temperatures; whereas it didn’t changed in specimens treated in buffer 7, 8 in 160°C but increased slightly in 180°C. The ratio (T1740/1506) was decreased in treated specimens in water and buffer 5, whereas it did not change in treated specimens in buffer 7, 8 in 160°C and slightly decreased in 180°C. The intensity of carbonyl peak (1740 cm-1) was higher in specimens treated in buffer 5, water, and buffer 7, 8, respectively. It seems that because of higher amount of acids released in higher temperature (180°C), the ability of buffers to buffer the medium decreased. Thus, deacetylation and degradation of carbohydrates increased, consequently. Buffering the medium of hydrothermal treatment in neutral level prevents the strength loss and extends the usage of heat-treated wood in load-bearing applications.
A Talaei, A Karimi


Quantification of copper and chromium in field stakes after different exposure times: Remaining metal content and distribution
2013 - IRG/WP 13-50291
In order to determine the distribution of copper and chromium as well as their remaining concentration EN 252 specimens and thicker pine sapwood stakes (non standard format) were treated with a commercial CC salt in a vacuum pressure process. The stakes were installed in the test field of the Institute of Wood Research, Hamburg, in August 2010. In all cases three stakes were removed after 4, 8, 12, 16 and 20 months of exposure, whereby the metal content was analysed after sample preparation. Based on these data and under consideration of the analytical values of unexposed stakes the remaining metal content was calculated for the above and in ground section. The results illustrate that 84 % of the copper remained in the full EN 252 samples and 77 % in the non standard stakes whereas the chromium content corresponds to 95 % and 85 %, respectively. On the other hand the data illustrate that in both sample sizes the highest copper and chromium amount was found in the above ground portion after exposure.
T Liese, M Bahmani, E Melcher


VOC-free remedial treatment agent on organic solvent basis with surface cleaning by photocatalysis using titanium dioxide
2014 - IRG/WP 14-40651
Due to the EU Regulations according to the harmonisation of the European market of biocidal products and the EU Regulations regarding emissions of volatile organic compounds in residential properties a new VOC free yet organic solvent based remedial treatment agent is introduced including a potential method to clean up the wooden surface of remaining biocides after a remedial treatment using photocatalysis.
H Ahl, J Fromm, P Jüngel, E Melcher, M Pallaske


How intraspecific radial variability of the European Oak’s may influence mild pyrolysis process and durability of the material
2016 - IRG/WP 16-40725
Last decades wood is promoted as building material. Unprotected wood exposed to outdoor conditions undergoes a variety of degradation induced essentially by fungi attacks. Heat treatment of wood by mild pyrolysis (180°C T 240°C under inert atmosphere) is a preservation process with a weak environmental impact, and therefore, is viewed as an interesting alternative to the chemical impregnation methods. It is generally well recognized that final properties of thermally modified wood like decay resistance, dimensional stability, mechanical properties or color depend on wood species but also and heat treatment process and treatment conditions like time and temperature. However, in spite of different studies describing the effect of inter specific variability on wood thermal degradation, no study describes the effect of intraspecific variability of wood on thermo modification processes. As wood physical properties as well as chemical composition can vary between and within species, between stands and even within tree, we tested the effect of radial position of European oak wood (Quercus petraea Liebl.) on its thermal stability. Samples of heartwood, sapwood, juvenile wood, earlywood or latewood taken from the radii of 2 trees were ground to fine sawdust subjected to thermogravimetric analysis (TGA) at 220°C for 2 hours using the same heating program. At the same time, holocellulose, cellulose and extractives as well as extracted heartwood and sapwood were also subjected to TGA using the same procedure. Results indicated that heartwood was more sensitive to heat than sapwood, the inner side of heartwood being more sensitive than the outer side. Differences were also noticed between native and extracted wood, the latter ones being less sensitive to thermal degradation. These results were consistent with the stability of each wood cell wall component indicating that extractives were more susceptible to thermal degradation than holocellulose, holocellulose being more susceptible than cellulose. At the ring level, earlywood was shown to be slightly more sensitive to thermal degradation than latewood. It was therefore concluded that since wood radial position and the earlywood/latewood ratio determine the thermal stability of oak wood, the quality and the homogeneity of initial wood boards should be carefully controlled to avoid heterogeneity in the treatment leading to end products with different properties and quality.
J Hamada, A Pétrissans, F Mothe, M Pétrissans, P Gérardin


Chemical Analysis of Southern Pine Pole Stubs Sixty Months Following Treatment with a Methylisothiocyanate-Based Solid Fumigant Stick
2019 - IRG/WP 19-30740
Methylisothiocyanate-based fumigants have been commercially used in the United States for over 35 years to control internal decay in utility poles and other wooden structures with little technological advancement. The most recently commercialized methylisothiocyanate-based fumigant is chemically known as dazomet. Dazomet is a free-flowing powder or granule that decomposes in the presence of moisture within a utility pole to release methylisothiocyanate. As a means to accelerate the decomposition to methylisothiocyanate, a copper solution can be applied to dazomet during the time of fumigant application. Laboratory and field studies conducted as part of the Utility Pole Research Cooperative at Oregon State University have demonstrated the long-term efficacy of dazomet. Concerns with applicator safety, inefficient copper-dazomet interaction, accurate dosing and a high potential for accidental spills, has led OSU researchers to develop several solid forms of dazomet. While long-term field testing by the OSU-UPRC has generated positive results, the prototype forms of solid dazomet had little commercial value. Recently, a commercially viable solid-stick dazomet product was introduced to the remedial wood preservative market to prevent and arrest active decay within in-service wood utility poles. To demonstrate the long-term performance characteristics of this solid form of dazomet, a field study was established in January 2014 in southern pine utility pole sections. At the fourth inspection conducted 60 months following fumigant treatment, chemical assay borings were removed at various pole heights and depths and analyzed for concentrations of methylisothiocyanate using GCMS. The 60-month results showed the concentrations of methylisothiocyanate were greatest in the pole sections treated with the copper amended solid-stick dazomet. When compared to previous chemical assay results at 12, 32 and 46 months following fumigant treatment, the 60-month results showed a sharp increase in concentrations of methylisothiocyanate in the copper amended solid-stick dazomet treated pole sections. The granular dazomet showed a slight increase in methylisothiocyanate production, where the unamended solid-stick and copper amended granular dazomet showed little change from 46 to 60 months of exposure. When compared to a methylisothiocyanate threshold value for decay fungi proposed by Oregon State University, the chemical assay results at 60 months indicated all fumigant treatments are effectively protecting the zone of fumigant treatment (15.2 cm below to 15.2 cm above groundline) of southern pine pole sections. However, the greatest protection within and above the zone of treatment was provided by the copper amended solid-stick dazomet treatment. Future sampling and chemical analysis of the southern pine pole sections are planned to monitor long term efficacy of the fumigant treatments.
D J Herdman, T Pope, R R Browning


Comprehensive protection of timber in seawater
2020 - IRG/WP 20-10970
The hazard of wood in seawater can be divided into two areas: Below the water level, shipworm (Teredo navalis) and gribble (Limnoria lignorum) can attack non-resistant or insufficiently protected wood; above the water level, there is a risk by wood-destroying fungi and, to a lesser extent, insects. In a national project funded by the Deutsche Bundesstiftung Umwelt (DBU, German Federal Environmental Foundation), in addition to various laboratory, field and practical experiments, the infestation risks, pest occurrence and protection possibilities of native coniferous wood species were investigated. However, the main focus of this paper is on laboratory studies on the fungicidal effectiveness of sea salt (sodium chloride) against basidiomycetes and in this context the distribution of sodium in roundwood after exposure in artificial sea water. The fungal tests according to EN 113 (1996) against the basidiomycetes Coniophora puteana, Poria placenta, Gloeophyllum trabeum and Coriolus versicolor prove that the mass loss is less than 3% at application rates above 15 kg NaCl/m³. The chemical analyses show that 20 cm above the water level an average sodium content of approx. 40.000 ppm (or the equivalent of more than 40 kg NaCl/m³) was quantified over the whole pine log cross-section, which is significantly above the derived fungicidal threshold value of 15 kg/m³. In addition, a brief overview of the results of field studies and observations on wooden constructions that were partially exposed to seawater in practice is given.
E Melcher, J Müller, T Huckfeldt


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&apos; exposure.
B R Richards, D A Webb


The effect of certain wood extractives on the growth of marine micro-organisms
1977 - IRG/WP 438
S E J Furtado, E B G Jones, J D Bultman


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