Your search resulted in 29 documents. Displaying 25 entries per page.
Resistance of Alstonia scholaris vestures to degradation by tunnelling bacteria
1992 - IRG/WP 92-1547
Electron microscopic examination of vessels and fibre-tracheids in the wood of Alstonia scholaris exposed to tunnelling bacteria (TB) in a liquid culture showed degradation of all areas of the secondary wall. The highly lignified middle lamella was also degraded in advanced stages of TB attack. However, vestured pit membranes and vestures appeared to be resistant to degradation by TB even when other wall areas in Alstonia scholaris wood cells were severely degraded. The size comparison indicated vestures to be considerably smaller than TB, and we suspect that this may primarily be the reason why vestures in Alstonia scholaris wood were found to be resistant to degradation by TB.
A P Singh, T Nilsson, G F Daniel
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
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
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 C CP/MAS NMR in the chemical identification of decayed and undecayed, tropical timber species
1984 - IRG/WP 1224
13C CP/MAS NMR was found to be an extremely powerful tool for elucidating the chemical composition of Eucalyptus maculata, Pinus elliottii and Alstonia scholaris. The differences in lignin composition were different for each timber and discussed in relation to decay caused by soft-rot and white rot fungi. In particular the presence of syringyl and guaiacyl lignin types are discussed.
L E Leightley
An insight into brown rot decay of timber as revealed by 13C CP/MAS NMR
1985 - IRG/WP 1259
L E Leightley
The isolation of actinomycetes from wood in ground contact and the sea
1980 - IRG/WP 1110
M S Cavalcante, R A Eaton
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
Decay types observed in small stakes of pine and Alstonia scholaris inserted in different types of unsterile soil
1990 - IRG/WP 1443
The attack of various wood-degrading microorganisms occurring in mini-stakes of pine and Alstonia scholaris buried in various types of unsterile soil was studied. Attacks by white rot, brown rot, soft rot, erosion bacteria, tunnelling bacteria and actinomycetes were found. Soft rot occurred in all soils, whereas attack by white rot and especially brown rot and erosion bacteria was rare. The type of soil influenced the occurrence of attack by tunnelling bacteria and actinomycetes. The former were mainly associated with horticultural soils whereas the latter were associated with soils from coniferous forests.
T Nilsson, G F Daniel
Dip-diffusion of dressed timber - Effect of drying
1989 - IRG/WP 3509
The effect of drying on dip-diffused dressed freshly sawn timber was determined by the depth of penetration of boron achieved on the two test timber species, White cheesewood (Alstonia scholaris) and Light Hopea (Hopea papuana). The results obtained showed that light density White cheesewood was completely penetrated even after 3 days drying while Light hopea, treated immediately achieved 5.2 mm penetration after 2 days diffusion and subsequently better after 14 and 21 days diffusion. Adequate penetration was only achieved after 14 and 21 days diffusion when there was delay between 30 minutes and 72 hours.
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
Hardwood field experiment - 10 year report
1989 - IRG/WP 3560
The international hardwood field experiment was planned in 1976 and set up in some 34 different sites around the world. The test stakes include 4 reference species common to each site and in most cases at least 2 species of local importance (supplementary species). It was hoped that a picture of performance of a range of economically important timber species would be built up and at the same time provide vital background information for people currently engaged in hardwood and soft-rot research. Obviously it proved impossible to set up such a large trial simultaneously and since the various sites are inspected at different times the data presented are for different time periods dependent on the site. The original intention was to present fully the data at year 10 when it was considered the test should be terminated. Three progress reports have been prepared giving details of the reference species (IRG/WP/3164), the supplementary species at the master site (IRG/WP/3200) and the data available in 1986 (IRG/WP/3391). The sending of results from the various sites has been rather erratic and despite precise instructions, sometimes results have been provided in a form difficult to interpret. Only sites submitting data for a minimum of 5 years are included in this report that is, 16 of the original 34 sites.
D J Dickinson, S M Gray
Dip-diffusion of dressed timber - Effect of drying
1990 - IRG/WP 3603
The effect of drying on BFCA dip-diffused, dressed, freshly sawn timber was determined by the depth of penetration of boron achieved on two test timber species, White Cheesewood (Alstonia scholaris) and Light Hopea (Hopea papuana). The results obtained showed that the light density White cheesewood was completely penetrated even after 3 days drying while Light Hopea, treated immediately achieved 5.2 mm penetration after 2 days diffusion and subsequently better after 14 and 21 days diffusion. Adequate penetration was only achieved after 14 and 21 days diffusion when there was delay between 30 minutes and 72 hours.
H C Konabe
Assessment of untreated Papua New Guinea timbers against subterranean termites. Progress report 2
1993 - IRG/WP 93-10040
Eight species of Papua New Guinea wood including Kwila (Intsia palembanica), Taun (Pometia pinnata), Malas (Homalium foetidum), PNG Walnut (Dracontomelon dao), Calophyllum (Calophyllum sp.), Kamarere (Eucalyptus deglupta), PNG Beech (Nothofagus spp.) and White Cheesewood (Alstonia scholaris) were exposed groun contact for their natural durability against subterranean termites. Inspection after 42 months showed that Kwila was still sound while Taun, Malas and PNG Walnut had minor attacks after the last inspection. The termites found attacking the stakes were Coptotermes obiratus, Microcerotermes repugnans and Nasutitermes novarum hebridarum.
M Rokova, H C Konabe
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 5: Interim report
1980 - IRG/WP 454
Wood samples (15 x 2 x 2 cm³) were treated with one copper/chrome/arsenic (CCA) and one copper/chrome/boron (CCB) preservative using the following concentrations - O, 3, 6, 10%. Treated samples of three reference wood species - Alstonia scholaris, Fagus sylvatica, Pinus sylvestris were supplied to all participants. Additional local species were chosen by participants and included in the test at their own test site. Values for preservative retention in all samples were noted. All samples were to be exposed for at least 7 years and examined for (a) marine borer attack after 6 and 12 months and yearly intervals thereafter, and (b) microbiological attack after 6 and 24 months' exposure.
R A Eaton
Evidence for actinomycete degradation of wood cell walls
1990 - IRG/WP 1444
Several unique patterns of degradation occurring in wood cell walls have been observed in wooden stakes inserted in unsterile soil in the laboratory. Some of the patterns have also been observed in coniferous wood taken from forest floors. All the observed attack types occur within wood cell walls, mainly within the S2 layer. Attack is characterised by channels of varying diameter or small fusiform cavities arranged in the form of a rosette. Some channels are narrow, 0.5-1.0 µm, and form a highly branched network. Other channels are wider, up to approx. 2-3 µm and less branched. All channels are produced by hyphae growing within the wood cell walls. Attack has been observed to arise from the branching of thin hyphae growing longitudinally in the fibre lumina. The small diameter of the hyphae and the fact that these decay patterns have not been described for wood degrading fungi indicate that actinomycetes may be responsible.
T Nilsson, G F Daniel, S L Bardage
Preliminary results from the field experiment to determine the performance of preservative treated hardwoods with particular reference to soft rot. The four reference timber
1980 - IRG/WP 3164
The results given in the Tables 1-4 each refer to one of the four reference species treated with four solution concentrations of CCA as recorded from each test site. The species are: Alstonia scholaris, Betula pendula, Fagus sylvatica, Pinus sylvestris. The treatments were: Untreated, 0.66% CCA, 1.53% CCA, 3.01% CCA, 5.60% CCA. Each figure is an average of the ratings recorded for each replicate of the species at a particular treatment and a particular inspection. The agreed ratings were: Sound - no attack (Condition): 0 (Rating); Slight and superficial decay (attack): 1; Evident but moderate decay (attack): 2; Severe decay (attack): 3; Failure - almost complete loss of strength: 4. Detailed instructions were set out in the IRG Document No: IRG/WP/367 of 1976.
J F Levy, D J Dickinson
Hardwood Field Experiment: Progress Report 1977-1986
1986 - IRG/WP 3391
The international hardwood field experiment was planned in l976 and set up in same 30 different sites around the world. The test stakes include 4 reference species common to each site and in most cases at least 2 species of local importance. It was hoped that a picture of performance of a range of economically important species would be built up and at the same time provide vital background information for people currently engaged in hardwood and soft-rot research. It is felt that these aspirations are more than being achieved and that as time proceeds this trial will prove invaluable in developing our knowledge of wood preservation on a world wide basis. Obviously it proved impossible to set up such a large trial simultaneously. Different sites also inspect their trials at different times and so the data presented is for different periods dependent on the site. The original intention was to fully present the data at year 10 when it is considered the test should be terminated. Two progress reports have been prepared giving details of the reference species (WP3164) and of the mixed species at the master site (WP3200). The sending of results from the various sites has been rather erratic and despite precise instructions, sometimes in a form making it difficult to interpret the results. However, it is felt that this is not a major problem as all the sites will have their own records and the gaps currently in the records should be easily filled in. In view of this we have decided to compile the available results as raw data together with the omissions. This will enable cooperators to check their data and fill in the gaps in their copy of the report and communicate this to the chairman who will pass it on to the other participants. When the final data is added to the records a final report will be written giving a detailed analysis of the data and drawing any necessary conclusions. The full details of the experimental plan are given in IRG document WP/367. However as many people may have misplaced this document the details are summarised here. Each sample was given a code number consisting of 6 digits. The first two digits indicate the participating country and person; the second two digits indicate the species of timber; and the last two digits indicate the treating concentration of preservative and the sample number. With reference to the list in 2.2 the code number 162305 indicates that 16 = Japan, 23 = Crytomeria japonica, 05 = Untreated controls, sample number 5, 2.2 Species list and participants. Due to late inclusion of some species it was not possible to maintain strict numerical order in the allocation of numbers to the species. Were sufficient material was supplied a replicate set of stakes was installed at Silwood Park, Imperial College, Surrey, UK.
D J Dickinson, S M Gray
IRG/COIPM INTERNATIONAL MARINE TEST - To determine the effect of timber substrate on the efectiveness of different preservatives in sea-water: Coding scheme
1976 - IRG/WP 420
It was agreed in Wildhaus on 15 May 1976 that preparations for the test detailed in Document No: IRG/WP/414 should commence immediately, but that initially only two water-borne preservatives should be used - a copper/chrome/arsenic (CCA) and a copper/chrome/boron (CCB) formulation respectively. PRL, England (R Cockcroft) would be responsible for supplying only the reference species treated with the CCA preservative and Dr Wolman GmbH, Federal Republic of Germany (W O Schulz) for supplying only the reference species treated with the CCB preservative. Untreated samples of the reference species would be supplied at the same time. The two batches of treated reference species would be despatched as soon as possible to the people concerned for the 13 sites agreed. The following is the coding scheme which is being used: The first two digits indicate the participating country and person; the second two digits indicate the species of timber, and the last two digits indicate the preservative treating concentration and sample number. The CCA treated samples will be those whose last two digits are from 01 to 37 respectively, and the CCB treated samples will be those whose last two digits are from 41 to 77 respectively. eg 10 01 31 indicates that 10 = Turkey (Dr Rifat Ilhan), 01 = Alstonia scholaris (Reference species), 31 = 1st replicate of samples treated with 10% (w/w) CCA solution.
Assessment of untreated Papua New Guinean timbers against subterranean termites. Progress Report 1
1990 - IRG/WP 1436
Eight major commercial timber species (Intsia palembanica, Pometia pinnata, Homalium foetidum, Dracontomelon dao, Calophyllum spp., Eucalyptus deglupta, Nothofagus spp., and Alstonia scholaris) were exposed in ground contact against termites. Five replicates of heartwood stakes of 25x25x250 mm³ of each species were randomly embedded in the soil. Results after 24 months exposure showed that Kwila was still sound while Taun, PNG Walnut, Malas and White Cheesewood had traces of termite attack on some stakes. All stakes of Calophyllum and PNG Beech were totally destroyed while three of Kamarere stakes were also destroyed. The termites found attacking the stakes were Nasutitermes graveolus, Coptotermes obiratus, Coptotermes acinaciformes and Microcerotermes repugnans.
M Rokova, H C Konabe
Information from the COIPM Wood Group. Summary received via Mme Dr Anna Gambetta (Italy)
1987 - IRG/WP 4139
Two co-operative programmes were discussed: 1) The IRG/COIPM co-operative programme on the CCA/CCB wood treatments and 2) The IRG/COIPM co-operative programme for testing the resistance of plastic wrapping for wooden pilings. The following was reported: In the wood treatment programme, beech, pine and alstonia wood samples have been pressure treated with 3 retentions (3%, 6% and 10%) of CCA and CCB and exposed in the sea, to find out if these timbers have selective resistance to attacks by marine borers and fungi. After nearly 8 years of exposure at many different locations it is becoming apparent that both treatments in pine and alstonia provide better protection than both treatments in beech. It is hoped to find out after chemical analysis why this is happening. In the polyolefin tests this plastic material was heat shrunk around small wooden blocks and exposed to borer attack in many different marine environments, and also in some terrestrial environments where termites were present, to determine if the material prevents attack by the borers. At two stations the test is now in its eighth year. So far the polyolefin material is still intact and has not been penetrated by borers. These two programmes are continuing.
J R DePalma