Your search resulted in 43 documents. Displaying 25 entries per page.
Immuno-electron microscopic localization of extracellular metabolites in spruce wood decayed by brown-rot fungus Postia placenta
1990 - IRG/WP 1441
Degradation by Postia placenta in spruce and birch wood was shown to occur not only in the wood cell wall but also in the middle lamellae region. Middle lamellae was often found to be degraded along the centerline so that cells could separate along this line. Extracellular membrane structures were found surrounding the hyphae and this matrix labelled positively with antisera produced to Postia placenta extracellular metabolites. This matrix was also visible in the secondary wall of degraded birch wood. Antisera labelling was also noted in the secondary cell walls of the wood cells, but not in the middle lamellae region.
Y S Kim, B Goodell, J Jellison
Factors affecting decay rates in a fungus cellar II
1986 - IRG/WP 2259
Tests were initiated to investigate the influence of various factors on the decay rate in a "Fungus Cellar". Birch and pine stakes treated with chromated copper arsenate and didecyldimethyl ammronium chloride, as well as untreated control stakes, were incubated in two soils in a Fungus Cellar test and installed at two field sites for comparative purposes. The visual rating vs actual stake weight loss relationship was also studied. Preliminary results from the initial Fungus Cellar test indicated differences in decay rates between birch and pine and also between soils. The decay rate observed for pine stakes was generally lower than birch in both soils. The decay rate was greatly accelerated in a Michigan soil with birch and pine over that observed in a Florida soil. Soil type had less impact on the primary decay present in the stakes. Soft rot was the primary decay associated with treated wood in both soils, while soft rot, basidiomycete, or combinations of the two were frequently found in untreated wood. The range of weight loss vs visual rating relationship was similar between wood species, treatment, and soil type. Weight losses tended to "overlap" the visual ratings regardless of the decay type.
P A McKaig
Developments in unsterile soil soft rot testing
1984 - IRG/WP 2210
Two unsterile soil test methods, the soil burial technique and a method using vermiculite burial with soil inoculation, were compared using different soils to determine their effectiveness in evaluation of wood preservatives against soft rot. Isolation of fungi and microscopy of decayed wood indicated that both methods produced accelerated soft rot attack in treated and untreated birch. Vermiculite burial with soil inoculation produced significantly higher and consistent weight losses over the range of preservative concentrations allowing more confidence in threshold retention selection.
P A McKaig
Factors affecting decay rates in a fungus cellar
1985 - IRG/WP 2242
Birch and pine stakes treated with chromated copper arsenate and didecyldimethylammonium chloride were incubated in two soils in a "Fungus Cellar" test. At three month intervals, sets of stakes were inspected and assigned visual ratings or removed from the soil beds for weight loss determination. Preliminary results after nine months exposure have shown differences in the decay rates between birch and pine and also between soils. Overall, the decay rate for pine, treated and untreated, has been considerably lower than birch in both soils. A Michigan soil accelerated the decay rates up to 3 times that observed for a Florida soil. Soil type also influenced the primary decay present in the stakes. Basidiomycete attack was observed in birch stakes treated with subthreshold retentions of both preservatives in the Michigan soil, while the primary decay in the Florida soil was soft rot. Untreated birch controls failed through basidiomycete attack in both soils. Soft rot was the primary decay in treated and untreated pine for both soils. However, more data is needed to determine if this trend will continue. Weight losses as low as 9.3% caused stake failure (visual ratings of 0). Basidiomycete damage caused stake failure at lower weight losses than soft rot. Regardless of the decay type, threshold retentions selected by weight loss or visual ratings were similar.
P A McKaig
Performance of preservative-treated hardwoods with particular reference to soft rot. Report of condition of specimens installed in Victoria, Australia
1980 - IRG/WP 3155
J Beesley, R McCarthy
1981 - IRG/WP 1138 (+ Addendum)
The stages of growth of soft-rot fungal hyphae in birch cell walls has been studied using transmission electron microscopy. These observations are compared with time-lapsed cinemicrographic studies on infection and cavity development within wood cell walls which show a start-stop hyphal growth pattern. The fine structure of hyphae during each stage of the decay process shows that hyphae penetrating the wood cell wall have dense, granular cell contents and few recognisable cell organelles. As cavities widen and the hyphae within them increase in size, a hyphal cell wall is laid down, septation occurs and cell organelles are present. At maturity, cavity hyphae become vacuolate, slightly distorted in form.
M D C Hale, R A Eaton
Soft rot cavity widening - A consideration of the kinetics
1984 - IRG/WP 1227
Studies on the micromorphology of soft rot cavity formation by Phialophora hoffmannii in birch using time-lapse cinemicrography are briefly outlined. A mathematical model is constructed to describe the cavity widening process, particularly changes in the surface area of a hypothetical cavity during enlargement. On comparison with observed data it is concluded that the rate of cavity widening is determined by wood cell wall characteristics.
M D C Hale, R A Eaton
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
Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper tolerant brown rot organism in leaching environments.
S M Gray, D J Dickinson
Collaborative field experiment: Analysis of copper and chromium in stakes of the four reference timbers
1982 - IRG/WP 3213
The stakes analysed belong to the Swedish set of the four reference timbers of the collaborative field experiment (Document No: IRG/WP/367). Before the field exposure 60 mm were cut off the end of each stake. This was done in order to be able to carry out chemical analyses as well as different types of testing. Some of the material has been used in softrot tests (Document No: IRG/WP/1151).
IRG test of preservative-treated hardwoods with particular reference to soft rot. Report on condition of specimens installed in Victoria, Australia
1983 - IRG/WP 3269
G C Johnson, J D Thornton
The use of image analysis to quantify soft rot decay
1992 - IRG/WP 92-2410
Image analysis techniques can provide quantitative information from visual images. As part of a wider interest in decay assessment methods we have investigated the application of image analysis techniques for quantifying soft rot decay by Chaetomium globosum in transverse sections of birch wood and bamboo. A method for reducing contamination of the section (and image) by the fungal hyphae and of staining prior to image analysis was developed. Decay cavities could be accurately detected and the extent of decay expressed in several different forms, with decay as a proportion of the wall area under analysis being the standard notation. Using a thin section exposure system it was found that, after a four day lag phase, soft rot decay in bamboo fibres increased at a constant rate, reaching 60% of wall area after fourteen days. The image analysis technique is rapid and straight forward to use, enabling the collection of both quantitative and qualitative data from the same area. It also allows different regions of a sample to be analysed separately. Further work with the technique is in progress to quantify decay in a wider range of timbers and to assess the effect of preservative treatments.
P J Wickens, R J Murphy
The effect of treatment temperature on the biological performance of CCA treated wood
1990 - IRG/WP 3624
Birch and Scots pine sapwood blocks were treated with several concentrations of CCA at three different temperatures: 5, 20 and 35°C. The treated wood was maintained at the appropriate temperature for the fixation period. Leached and unleached samples were then exposed in a soft rot monoculture test using Chaetomium globosum and a brown rot monoculture test using Coniophora puteana. The treatment temperature had little effect on the performance against brown rot but the performance of birch against the soft rot improved as the treatment temperature increased particularly after leaching.
S M Gray
Water-borne wood preservatives against marine borers. Results from NWPC marine trials started in 1972 and 1976
1990 - IRG/WP 4162
The paper presents the results from NWPC (Nordic Wood Preservation Council) marine trials started in 1972 and 1976. The trials are carried out according to the NWPC Standard No. 220.127.116.11./73 "Marine test - a test against marine wood boring organisms in sea water". The test site is Kristineberg Marine Biology Station on the west coast of Sweden. The wood blocks used in the trials were made from sapwood of European redwood (Pinus sylvestris L.). European beech (Fagus sylvatica L.), European birch (Betula spp.) and Norway spruce (Picea abies (L.) Karst) were also used to a minor extent. In all, 19 water-borne wood preservatives were tested. The preservatives consisting of copper-chrome, copper-chrome-arsenic, copperchrome-boron, copper-chrome-phosphorus and tributyltin oxide gave best performance. The ammoniacal copper preservatives failed to protect the wood against marine borers.
Ö Bergman, C Lundberg
Aspergillus fumigatus Fresenius resistance to chemical preservatives in piles of pine and birch wood chips
1981 - IRG/WP 1146
Investigation has been carried out on the communities of fungi developing in birch and Scots Pine chip piles in the Ostroleka Pulp and Paper Mill in the North-East of Poland The species composition or fungal communities and their development in a dozen of chip piles during storage was investigated. Untreated and chemically treated birch and pine wood chips were investigated. In all samples the great amount of Aspergillus fumigatus infested chips were found. This fungus displayed resistance to chemicals used as chips preservatives and occurred often more frequently in the wood of chemically treated than untreated chips. The course of investigations and quantitative occurrence of Aspergillus fumigatus in relation to other important fungi species are presented in this paper.
M H Zielinski
Ultrastructural observations on wood-degrading erosion bacteria
1986 - IRG/WP 1283
G F Daniel, T Nilsson
IRG soft-rot stake test - Site 03 Australia. Progress Report No. 3
1982 - IRG/WP 3202
The performance of test stakes was examined after four (4) years. Hardwood stakes treated with CCA showed significant soft-rot attack. The exception to this was Alstonia scholaris which was similar in performance to Pinus sylvestris. A supplementary test containing stakes treated with CBC, PCP and creosote, showed attack in all hardwoods examined. Little decay was found in stakes of Pinus sylvestris treated to low retention levels of CBC.
L E Leightley, R S Johnstone
IRG soft rot stake test. Site: 03 Australia. Progress repor
1980 - IRG/WP 1114
IRG soft-rot test stakes were installed in site 03 Australia 16.6.77. The stakes have been inspected twice, (28.11.78 (Johnson, 1979) and 31.10.79) for signs of decay, and used to obtain fungal isolates. The condition of stakes in the supplementary soft-rot test has also been examined.
L E Leightley, D M Francis, R S Johnstone
Copper based water-borne preservatives: The use of a thin section technique to compare the protection of wood by copper based preservatives against soft-rot and bacterial decay
1987 - IRG/WP 2286
This paper describes the techniques developed and gives examples of results obtained for the performance of copper based wood preservatives against both the bacterial and fungal hazards.
A M Wyles, D J Dickinson
Effectiveness of Busan 30 treated birch blocks in a soil medium
1987 - IRG/WP 3409
TCMTB based formulation has been anticipated for use in dip-diffusion treatment in Papua New Guinea to replace BFCA Wood preservative. One such formulation is the Penacide (TCMTB + MBT Boron) which is currently being tested against fungi and insects. Accelerated laboratory test in soil exposure was employed to test a related formulation (Busan 30) to determine its effectiveness against soil inhabiting organisms. In general the formulation was effective at a toxic threshold limit of 3.8 kg/m³.
H C Konabe
Influence of variable lignin content on brown rot decay of wood
1987 - IRG/WP 1320
Compilation of published data and new experiments with brown-rotting fungi on different timber species suggest that their decay activity, in contrast to soft rot and white rot fungi, is not greatly influenced by the type or amount of lignin present.
T Nilsson, G F Daniel
CCA modifications and their effect on soft rot in hardwoods. Part 2
1983 - IRG/WP 3244
The work outlined in this document is a continuation of that presented in Document No: IRG/WP/3201. The findings described in the previous paper are summarised below: a double treatment of CCB followed by arsenic (CCB+A) is more effective than a double treatment of boron followed by CCA (B+CCA) or a single treatment of CCA, CCB or CCAB in controlling soft-rot due to Chaetomium globosum in birch. CCB+A is as effective as the other formulations in controlling Coniophora puteana and Coriolus versicolor in birch and scots pine. CCB fails to copper tolerant basidiomycetes such as Coniophora puteana (F.P.R.L. 11E). A further investigation into the relative activities of CCA and CCB+A was carried out in a soil-bed using loss in strength and loss in weight as the criteria of decay. At the same time some aspects of the chemical nature of the formulations were examined in an attempt to explain the different performances of the treatments in birch. Amongst these tests, gross chemical analysis of the treated woodblocks and observation of the progressive fixation of the preservatives were the most significant.
S M Gray, D J Dickinson
Evidence for wood cell wall degradation by the blue stain fungus Botryodiplodia theobromae Pat
1994 - IRG/WP 94-10077
Botryodiplodia theobromae Pat., a world wide ubiquitous polyfagus sapstain fungus, was found able to destroy the cell walls of birch fibres (Betula verrucosa Ehrh.) but not Caribbean (Pinus caribaea var. hondurensis Barr. and Golf.) and Scots pine (Pinus sylvestris L.) tracheids. The fungus caused characteristic erosion of fibre cell walls similar to soft rot type 2; destruction of the S1 - S2 interface and delamination and degradation of the S2 layer. No attack of middle lamellar regions or birch vessel walls was noted.
O Encinas, G F Daniel