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Application of energy dispersive X-ray fluorescence spectrometry to the quantitative analysis of organotin preservative solutions and treated wood
1978 - IRG/WP 3125
One technique frequently used for the quantitative analysis of material containing inorganic compounds is energy dispersive X-ray fluorescence spectrometry. It has been shown previously that this technique can be readily used to determine the retentions of chromated copper arsenate and ammoniacal copper arsenate treated wood. This paper reports the results of a preliminary study to determine whether energy dispersive spectrometry may be used to assay both organotin treated wood and also the preservative in solution. Five objectives were established for the study and they were (i) Assessment of the instrumental error; (ii) Determination of the error due to sample preparation; (iii) Selection of a suitable live data accumulation time; (iv) Preparation of a calibration graph using tributyltin acetate; and (v) To initate studies on interelement interference effects.
J N R Ruddick


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


Evaluating the Process of ACQ-Treated Woods with TGAand CEM Analysis
2007 - IRG/WP 07-20374
To provide an understanding of the fundamental thermal behaviour and the disposal-end products of ACQ-treated woods, this study is comprised of two categories of examination. The first is related to the use of TGA under different thermal decomposition conditions (nitrogen or air, and 5 or 40 oC/min), and the use of EDX to examine certain residual elements of the char. The second applies the CEM techniques to evaluate the emission gas concentrations of O2 and CO2 concentration, the emission content (CO, SO2, NOx), and the emission gases temperature were measured using a Flue-gas Analyzer from the exit of a 45° flammability testing cabinet as specified in the continuous emission monitoring. The results of the TGA showed that the char of ACQ-treated woods at air atmosphere were less than that at nitrogen, and the pyrolysis temperature for the heating rate of 5 oC/min was lower than that of 40 oC/min, but both them were with the same amount of char. The results of the EDX analysis of ACQ-treated woods obtained that the main element is C (77.89 %), and that the relative proportion of Cu was 2.67 %. The results of CEM indicated that the emission gas temperature of ACQ-treated woods rise rapidly up to about 250 oC and then slowed down in the temperature range of 200 oC shown as a Plateau curve. The concentration of O2 decreased from 20.7 % to about 17 % linearly, and on the contrary the concentration of CO2 increased from 0.2 % to about 2.5%. Both O2 and CO2 then approached the shape of a Plateau curve until the end of the combustion time, as well as had a close relationship during combustion. For the maximum value of the emission content during the combustion, the emission quantity of CO was about 160 ppm. The SO2 emitted gas was zero. The peak for NOx gas was 25 ppm.
Han Chien Lin, Tsang-Chyi Shiah, Jung Ting Tsai


Evaluation of rapid methods for detecting wood preservatives in waste wood
1994 - IRG/WP 94-50024
For the disposal of wood waste under ecological sound conditions information about its hazardous potential is required. Several analytical methods are available for the detection of most elements in wood preservatives. Industrial process conditions, however, demand methods with very short turn around times. In this research several methods of analysis were judged on their speed and accuracy. A number of inorganic wood preservatives and organic preservatives containing detectable elements were studied (i.e. CCA, CCB, ZKF, CC, PCP [Cl]). Both solutions and treated wood samples were analyzed with energy dispersive X-ray fluorescence (EDXRF), laser-ablation ICP and coulometry. The coulometrical methods provided very precise analyses of solid wood in a turn around time of approximately 10 minutes. With laser-ablation ICP the results were unreliable. This is caused by the solid sample preparation procedure. EDXRF can provide reliable analyses in approximately 30 seconds. This method is not suitable, however, at low levels of concentration (< 50 ppm).
W J Homan, H Militz


Detection of defects in standing poles by X-ray techniques
1980 - IRG/WP 2132
The application of X-ray techniques to wood pole inspection procedures has been evaluated. Internal defects were accurately identified using X-ray inspection methods. These methods and their possible influence on the safety and economic aspects of wood pale utilization are discussed.
W D Gardner, R S Johnstone, W Pitt


Comparative studies on the distribution of lignin and CCA elements in birch using electron microscopic X-ray microanalysis
1987 - IRG/WP 1328
The microdistribution of metal preservatives in treated wood has received considerable research over the last two decades. Despite this, little effort seems to have been made to try and correlate the distribution of CCA elements with respect to naturally occurring wood cell wall components in wood. In the present preliminary study an attempt is made to relate the distribution of lignin in-situ with that of CCA elements. For the study matched samples of Betula verrucosa were first either mercurized to specifically label the lignin or vacuum impregnated with a commercial 2% K33 CCA preservative solution. Thereafter using SEM-EDXA, the relative distribution of labelled lignin and CCA elements were compared for both different cell types and cell wall regions. Results showed the relative microdistribution of CCA to follow closely that of the lignin distribution. Regions showing high lignin levels showed high CCA levels and vice-versa. Highest CCA and lignin levels were recorded in the vessel, fibre and ray middle lamella cell corners regions while the lowest levels were detected in the fibre (S2) secondary walls. Both the low lignin level (and syringyl type) and CCA uptake in fibre S2 walls would seem in close agreement with the known high susceptibility of these elements to soft rot attack in both treated and untreated birch. Comparisons made between the lignin content of the S2 layer for birch fibres and other known soft rot resistant species (e.g. Alstonia scholaris) showed great differences, with the latter showing much higher lignin (ca 3x) levels.
G F Daniel, T Nilsson


Ultrastructural and TEM-EDAX studies on the degradation of CCA treated radiata pine by tunnelling bacteria
1985 - IRG/WP 1260
An ultrastructural study was carried out on bacterial attacked Pinus radiata stakes treated with a high level (24.7 kg/m³) of Tanalith NCA preservative. The purpose of the investigation was to determine whether the organism possessed intracellular and/or extracellular detoxification mechanisms in order to overcome the high levels of copper, chrome and arsenic present within the wood fibre walls. Correlated T.E.M. and T.E.M.-EDAX studies showed most of the preservative elements to remain outside the bacteria associated with bacterial tunnel wall and cross-wall extracellular secretions. T.E.M.-EDAX showed the levels of preservative elements present in the tunnel walls and cross walls to often greatly exceel that recorded in neighbouring S2 cell wall regions, while studies on the bacteria showed that only copper and very low levels of chromium and arsenic had entered the cells. Observations suggested that the metals found within the cells were associated with electron-dense deposits or inclusions within the nuclear region or cell cytoplasm, the deposits often containing high levels of phosphorus and calcium together with lesser levels of other cations. The study also provided evidence for the direct visualisation of CCA preservative elements within fibre walls using T.E.M. without any form of secondary chemical enhancing, and in addition, considerable new information on the nature and structure of the single celled, Gram-negative, motile bacteria involved in the decay.
G F Daniel, T Nilsson


X-ray analysis of selected anatomical structures in copper/chrome/arsenic treated wood
1973 - IRG/WP 320
Application of analytical electron microscopy to problems in wood preservation has been very limited. Indeed, less than ten workers appear to have published their results using the technique, and of these&apos; only two papers deal with energy dispersion procedures in the scanning electron microscope; the others employ the more familiar wavelength dispersive methods of the electron probe.
H Greaves


Bacterial staining of samba (Triplochiton scleroxylon)
1988 - IRG/WP 1362
Red- and green-stained areas on Samba wood have been tested by IR, X-ray and Neutron Activation Multielement Analysis. No difference could be seen between stained and unstained areas. The red- and green-staining seem to be related to the bacteria Pseudomonas aeruginosa which were isolated from both red- and green-stained areas on the wood surfaces.
K Hansen


A study of salt imbalances observed in recycled copper/chrome/arsenic preservative solutions in commercial practice
1987 - IRG/WP 3461
The study reported monitored tank solutions, sludge and other by-products using a standard CCA solution, when recycled. This recycling of the CCA solution is quite usual in between any commercial treatment schedules. Salt imbalances were observed and the possible reasons for such phenomena were studied. The paper discusses the procedure followed, the method of sampling the liquid after the charge and the analysis, to arrive finally at an aggregation and conclusion from the data.
V R Sonti, S Sonti, B Chatterjee


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 9: Report of third inspection (2 years) in Italy
1980 - IRG/WP 461
The wood samples were submerged in the sea at Follonica, Italy, in April 1977. Follonica, latitudine 42°55&apos; North and longitude 10°45&apos; East, is situated on the Tyrrhenian sea. The recorded temperature varies between 13°C to 25°C, salinity 37-38% and pH about 8. The inspections were carried out after 6 months (10/1977), 1 year (4/1978) and 2 years (4/1979).
A Gambetta, E Orlandi


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 7: Second report on the samples in Papua New Guinea
1980 - IRG/WP 459
This report presents the findings to date regarding specimens installed in Papua New Guinea, as part of a world-wide marine trial of certain timbers treated with CCA or CCB preservatives. The details of the trial are set out in document number IRG/WP/414. The report discusses the findings in the context of the conditions prevailing at the trial site and of the properties of the trial timbers. The trial is the third to be installed in the waters of Papua New Guinea. In 1967, pine and eucalypt samples treated either with CCA or with creosote, were installed at Rabaul, Lae and Port Moresby. Tamblyn et al (1978) describe the performance of these samples. A second trial, consisting of fifteen Papua New Guinean timbers, vacuum/pressure treated with CCA, was established at Lae and Port Moresby in 1973. This trial is described in the report of Rayner (1974). The necessity for effective treatment against marine borer attack is particularly evident in the waters of Papua New Guinea. Shillingaw and Moore (1974) found that most wharves constructed around the coast of New Guinea during the war became unserviceable within eighteen months. A timber which has a considerable reputation for durability in Australian waters - turpentine (Syncarpia glomulifera) - has proved to be vulnerable to borer attack here; it gives a service life of as little as two years at Wewak, though a somewhat longer life can be expected at Port Moresby. The most destructive borers in these waters are the members of the family Teredinidae. Nearly forty species of teredinids occur here. The isopods, Limnoria and Sphaeroma are also responsible for damage to timber wharf installations in certain areas. The pholad Martesia is also found, but never in sufficient numbers to cause economically significant damage.
S M Cragg, C R Levy


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 20: Report on the inspection of specimens at Sekondi, Ghana after 48 months
1985 - IRG/WP 4116
The results of the second inspection of CCA- and CCB-treated test panels exposed at Sekondi, Ghana, in June 1980, are presented. The panels of Pinus sylvestris treated with 3% CCA are stil unattacked after 48 months. Panels treated with 10% CCA and still in test (Fagus sylvatica, Pinus sylvestris and Alstonia scholaris) are still free of attack. Locol species treated with 3% CCB have all been destroyed. Of the panels treated with 10% CCB recovered from the bottom of the sea, those of Ongokea gore were shown by X-radiography to be in various stages of attack by teredinids. One recovered panel of Erythrophleum guineense and four of Mitragyna stipulosa remain free of attack. Teredinids constitute the major hazard.
F F K Ampong, N Asare-Nyadu


Summarized comparison of four techniques for detecting defects in poles
1979 - IRG/WP 2126
Since our discussions in open session of Working Group II at Peebles, a number of workers in Australia have collaborated in comparing the efficacy of X-ray, sonic testing, or resistivity measurements for detecting internal defects in poles. The purpose of this circular is to draw to your attention some of the results, in summary form. No attempt has been made to compare techniques. More detailed accounts may be published at some future time by the individual workers concerned. Forty condemned eucalyptus telegraph poles were assessed by traditional inspection methods (hammer sounding and boring), X-ray scanning, Resotest Pole-Check sonic tester, and Shigometer resistivity technique. The work was planned and carried out by Messrs Johnstone and Gardner (Forest Commission of N.S.W., Wood Technology and Forest Research Division), Messrs McKitterick and Seaman (Telecom Australia) and Dr. Thornton of this Division who collaborated in examining 22 of the poles with the Shigometer. The results are summarised in the Table and some of the more interesting poles are shown in the figures. Unfortunately, details of the X ray scanning are not available for dissemination at this stage and therefore they have been omitted from the Table. For interpretation of the data obtained with the Shigometer, Dr. Thornton has combined the instrument&apos;s readings with application of it&apos;s probe to detect sound wood, i.e. less than 40 mm of sound wood remaining together with readings which suggest the presence of internal defects results in the pole being condemned. Note also in the case of the Resotest Pole-Check a suspect reading means that the poles should be re-assessed by traditional boring and sampling. Dr. Thornton and I wish to stress that we believe the instruments used in this study are valuable as aids to the linesman/pole inspector; we consider that no system should be put forward as the sole indicator of whether a pole has failed or not.
H Greaves


Comparative studies on the species effects of wood preservatives
1989 - IRG/WP 3521
For the examination of the resistance against fungal attack, wood blocks of 3 softwood species were treated with CCA (type 3), CFK, AAC and IF-1000 independently. The wood blocks were exposed to the fungal decay with Tyromyces palustris. The degradation of the wood blocks treated with these preservatives was quite widely different among wood species examined in this study. Hem-fir treated with CCA and radiata pine treated with CFK showed less durability than the other species and other preservatives. In the case of Cryptomeria japonica, all preservatives tested gave good results. The micromorphological distribution of preservatives in cell walls was investigated with the wavelength dispersive X-ray spectrometry. The X-ray photoelectron spectroscopy was applyed for the investigation on the possibility of conversion reactions with preservatives in impregnated wood. The interaction of extractives with preservatives was examined using a conventional bioassay method for evaluations of the efficacy of wood preservatives against fungi. The concentration of Cr in the CCA treated wood was 1.5-1.6 times higher in the ray parenchyma cell walls than in tracheid walls in every wood species examined. The oxidation of wood occur during the treatments with CCA and CFK, however, there were not conspicious differences in the degree of oxidation among wood species. Although the hot water extractives themselves accelerated the mycelial growth, only the extractives of hem-fir reduced the efficacy of CCA.
K Yamamoto, S Matsuoka


X-ray photoelectron spectroscopic analysis of CCA treated wood
1992 - IRG/WP 92-3700
Ponderosa pine and Douglas-fir wood sections were treated with CCA preservative. To elucidate the mechanism of fixation of the CCA, the wood surface was analyzed by X-ray photoelectron spectroscopy (XPS). CCA treatment increased C1 (carbon bonded to carbon and/or hydrogen) and decreased C2 (carbon bonded to one oxygen) in XPS C1s spectra, both in unextracted and pre-extracted sections. This suggested oxidation of hydroxyl groups on cellulose and/or lignin by CCA occurred, followed by the decarboxylation of carbonyl and carboxyl groups. However, the large changes in the state of the carbon atoms recorded during CCA treatment of unectracted wood would appear to be due to migration of extractives to analyzed surfaces as well as to the oxidation of hydroxyl group in wood by CCA. Accelerating fixation produced more C1 than fixation at ambient temperatures. More increase of C1 was related to higher performance against leaching in the accelerating fixation. Surface concentrations of CCA elements determined by XPS was lower in the accelerating fixation than in the usual fixation, which could be one of the causes of lower water repellency on the surface of former section. CCA fixation resulted in a higher water repellent surface, especially in the presence of extractives.
J N R Ruddick, K Yamamoto, P C Wong, K A R Mitchell


Laboratory evaluation of chlorothalonil against the Formosan subterannean termite
1992 - IRG/WP 92-1559
The fungicide chlorothalonil was evaluated as a wood preservative to prevent attack by the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Southern yellow pine wafers treated with chlorothalonil (CTL) in P9 oil, CTL + chlorpyrifos in P9 oil, or CTL in xylene were conditioned by evaporative aging at 40° C for 4 weeks and exposed to termite attack in a modified ASTM D3345 4-week laboratory test. Actual CTL retentions were assayed post-test by X-ray fluorescence, and an approximate 50% decrease in CTL concentration found from the pretest nominal CTL retentions. With all three treatments, termite feeding on wood with actual retentions of 0.05-0.10 pcf (corresponding to 0.10-0.21 pcf nominal) did not differ significantly from the respective solvent controls. CTL retentions of 0.13-0.15 pcf (0.41-0.45 pcf nominal) limited wood weight loss from termite feeding to 6-13%, and retentions of 0.26-0.39 pcf (0.81-0.94 pcf nominal) CTL resulted in only 3-4% wood weight loss. Termite mortality was correlated with CTL retention. These results demonstrate that chlorothalonil is toxic to termites, and at the appropriate retention will deter Coptotermes formosanus from feeding on treated wood.
J K Grace, P E Laks, R T Yamamoto


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 3: Report of first inspection of samples at Lae, Papua New Guinea
1978 - IRG/WP 446
Samples for the international marine test were placed on frames numbered I to VII. Frames numbered VII of both CCA and CCB trials are being stored dry in the laboratory at F.P.R. & D.C. Frames I to VI of both trials were suspended in the sea at Lae Harbour (Morobe Province, Papua New Guinea) on 6th December 1977. The first inspection of the CCA trial was carried out on 8th June 1978, at which time the samples in frame VI were removed and posted for microbiological examination, while frames V and VI were X-rayed. Due to the considerable discrepancy between the results of visual and of X-ray examination, it was decided that all frames should be X-rayed. Unfortunately, this could not be carried out until 22nd August 1978. At this time, the samples in frame IV of the CCB trial were removed and posted for microbiological examination. The samples were X-rayed on a Toshiba Rotanode. Best results were obtained by operating at 50 kV and 50 mA, and by using an exposure time of 0.16 s. X-ray pictures of the samples were examined and the degree of teredinid attack was given a rating from 0 to 3 (see IRG/WP/414). The loss of many of the control specimens can be attributed to extremely heavy teredinid attack. Indeed, in some cases, small teredinid-riddled traces of the samples remained. Specimens of Fagus sylvatica and Pinus sylvestris which were heavily attacked in June were missing by August. The X-rays of four samples made in June 6th are compared with those made on August 22nd and a particularly striking example of rapid attack in the period intervening between the two inspections is shown. Neither pholad nor crustacean attack was observed in any of the samples, which in June were attacked. There were no marked differences between the degree of fouling on different samples. In each case the fouling completely covered all surfaces, but did not project much from the sample blocks. A typical example of this fouling which is probably best described as grade 2 fouling (moderate) is shown. Bryzoans covered more surface area than the other fouling organisms. Other microscopic fouling organisms which were common were bivalves, hydrozoans and sponges. Insufficient information is available on the marine fauna of Papua New Guinea to enable a detailed description of the fouling community to be made.
S M Cragg, C R Levy


Environmental consequences of various materials in utility poles - A life cycle analysis
1992 - IRG/WP 92-3726
A model for environmental life cycle analysis, LCA, has been created to compare environmental impact from transmission poles, made alternatively of concrete, steel, aluminium and pine wood treated with CCA type B or creosote. The main pollution sources and energy use are included in the LCA. One pole size, 12 meters long, is presented in the study, a so called "45 kV" pole. Poles of different materials can be divided into different groups considering different types of pollution. The use of poles made of concrete, steel and aluminium leads mainly to emission to the air, while treated wood mainly leaches preservatives during the operation and service phase. It is, by the knowledge we have today hard to compare these two types of discharge.
M Erlandsson, K Ödeen, M-L Edlund


A comparison of analytical techniques
1995 - IRG/WP 95-20061
This paper compares carefully-controlled weight retentions and analysis by XRF, ICP, combustion methods and a new extraction procedure for the new preservative, Copper(II) Dimethyldithiocarbamate (CDDC). Various experimental parameters such as particle size and drying conditions were investigated. In general, the correlations between and among the procedures are very high. The extraction-colorimetric procedure developed for assay of CDDC was verified by comparison to AWPA Standard analytical techniques.
A C Gallacher, C R McIntyre, M H Freeman, D K Stokes, W B Smith


Determination of bis-(N-cyclohexyl-diazeniumdioxy)-copper in different matrices by photometer, thermal energy analyzer and HPLC
1999 - IRG/WP 99-20179
For the quantitative analysis of bis (N-cyclohexyl-diazeniumdioxy)-copper (Cu-HDO) three analytical methods are used. The employment of the different methods depends on the matrices involved. For several years now, the colorimetric determination of Cu-HDO by photometer has been applied to solutions and concentrates of wood preservatives. In principle, the technique consists of a quantitative conversion of Cu-HDO into a Fe-complex and the measurement by photometer compared to a calibration curve in a range of 20 to 220 mg Cu-HDO per liter. The colorimetric technique is unsuited to extracts of complicated materials such as soil or wood because of disturbances due to other ingredients of these matrices. Further, the method is not suitable for samples with a concentration below 10 mg Cu-HDO per liter. In the case of difficult analytical problems in the determination of Cu-HDO (e.g. soil or air from working areas) another technique, involving the detection by Thermal Energy Analyzer (TEA), is applied. In the first step of the method, Cu-HDO sets nitrogen monoxide (NO) free by a reduction reaction with NaI / acetic acid / sulphuric acid in a laboratory converter. A helium gas flow transfers the nascent NO into the TEA. There, NO is detected by chemiluminescence which originates from its reaction with ozone. The large expenditure of work and the high costs of the instrumental equipment are handicaps for a wide use of the analysis by TEA. A new technique based on the widespread analytical system HPLC was therefore developed to determine Cu-HDO in the important matrix wood. The chipped wood sample is first leached by a mixture of methanol p.a. and 0,05 M KH2PO4-solution at room temperature and the content of the active substance subsequently analysed in the filtered extract by HPLC with UV-detection. The concentration is calculated on the basis of external standard calibration. In studies carried out on impregnated pine samples (pinus sylvestris) in different laboratories, percentage recoveries for Cu-HDO of more than 80% were achieved.
J Wittenzellner, W Hettler, M Maier


The micro-distribution of copper/chrome/arsenate in Acer pseudoplatanus and Eucalyptus maculata
1973 - IRG/WP 319
The excellent field performance of copper-chrome-arsenate (CCA) treated timber has been accepted for many years. The preservative loadings used in practice have been based on field trial results, backed by service tests. The performance of treated hardwoods in trials and practice indicated that provided the required loading and penetration could be achieved the performance would be good. Recent unexpected failures in a few hardwoods treated to specification indicate that some hardwoods behave differently in ground contact from the normal test species with equal preservative loadings. Field evidence with creosote suggests that some discrepancies can occur with other preservatives as well. The immediate problem is confined to a vary few species and in all cases failure has been due to soft-rot at the ground line. Petty & Preston (1968) demonstrated that CCA preservatives penetrate deeply into the tracheid wall of conifers affording excellent protection to the timber. It was decided to investigate the micro-distribution of CCA preservative components in two problem hardwood species, Acer pseudoplatanus and Eucalyptus maculata. If the components were found to be distributed less uniformly than in softwood tissues this could possibly account for the unexpected field performance of these hardwoods in ground contact.
D J Dickinson


Amenability of radial permeability of Sitka spruce (Picea sitchensis (Bong.) Carr.) as affected by aspects of cell ends in uniseriate ray parenchyma tissue
2003 - IRG/WP 03-40252
The principal objective of this article was to recognise and understand the amenability of ray parenchyma cell ends (end platform) in uniseriate ray tissue to influence the radial permeability of Sitka spruce (Picea sitchensis (Bong.) Carr.) by examination of most (Queen Charlotte Islands in Rhondda, South Wales) and the least (South Oregon in Dalby, North-East England) seed origins that grown in Britain. These seed origins were selected because they showed extremes in radial permeability using a copper-chromium-arsenic wood preservative full cell treatment. Differences of radial permeability of this extreme seed origins were explained by a detailed examination of the structures of the uniseriate ray parenchyma cell ends by SEM and Image Analysis. The data of the microscopic observations was analysed and differences in cell composition and dimensions were observed. The results showed that the nature of the simple pits in ray parenchyma cell ends and the condition of the end platform were the most significant factors affecting radial permeability in Sitka spruce.
I Usta, M D C Hale


Interactions between soft rot fungi and CCA preservatives in Betula verrucosa
1988 - IRG/WP 1367
Ultrastructural investigations were carried out to obtain information on the cell wall distribution of CCA elements during soft rot decay of 4% K33 CCA preservative treated birch (Betula verrucosa) wood. TEM observations on fibres at various stages of S2 cavity formation by mutabilis showed a distinct pattern of electron dense materials to occur within the S2 cell wall region. These materials (granular and fibrillar) were observed either concentrated around existing or previously existing cavity hyphae or more loosely associated within intervening hyphal S2 regions. TEM X-ray microanalytical studies on these materials showed high levels of CCA to be present particularly with the granular materials (thought to be melanin type material) associated with fungal hyphae; levels which greatly exceeded that recorded in neighbouring, but undegraded S2 cell wall regions. Lesser CCA levels were also found associated with non-hyphal electron dense fibrillar-like materials produced as a result of either true soft rot cavity formation or erosion attack within S2 fibre cell walls. X-ray studies on cavity hyphae has so far shown only significant levels of copper and possibly arsenic to have been taken up, and to be located in both the ground cytoplasm (only Cu) and in electron-dense bodies (Cu and As). The distribution of CCA in the degraded wood cell walls is discussed with respect to both the decay pattern, metal resistance of the fungus and the known biochemical nature of the attack process by soft rot fungi. Aspects of extracellular CCA detoxification by Phialophora mutabilis and other soft rot forming Phialophora species are further considered.
G F Daniel, T Nilsson


Direct analysis from wood of the blue stain fungi Aureobasidium pullulans and Hormonema dematioides by denaturing gradient gel electrophoresis
2006 - IRG/WP 06-10595
Aureobasidium pullulans and Hormonema dematioides are the two organisms used in the EN 152 laboratory method for determining the effectiveness of preservatives against blue stain in service. The literature concerning the disfigurement of surface coatings and exposed timber in-service states that A. pullulans is the dominant blue stain fungus, due to its frequent isolation from stained material. Inaccuracies when differentiating morphologically between isolates of these two related species have previously been highlighted bringing the conclusion concerning the dominance of A. pullulans to question. PCR-DGGE has been used to determine the environmental profile of the two blue stain fungi; A. pullulans and H. dematioides and to establish which of these organisms is most prevalent on a range of stained timber samples taken from trials and in service. The DGGE analysis indicated that a member of the Dothioraceae family, most likely H. dematioides was more commonly present on stained timber samples under five years old. No blue stain fungi were detectable by PCR-DGGE in older samples over 25 years old. With the correct primer choice PCR-DGGE is able to differentiate between different species and the level of abundance at which those species are represented in a sample. It is clear from this study that A. pullulans is not as dominant on stained timber as would have been expected. On this basis it is suggested that H. dematioides should be the preferred species for research and development work in this field.
M J Ray, D J Dickinson


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