Your search resulted in 227 documents. Displaying 25 entries per page.
The attack of naturally durable and creosote treated timbers by Limnoria tripunctata Menzies
1995 - IRG/WP 95-10132
Limnoria tripunctata was found tunnelling in creosote treated Douglas fir (Pseudotsuga menziesii) pilings and naturally durable greenheart (Ocotea rodiaei) gate seals at two sites on the south coast of the United Kingdom. Examination of thc creosote-treated wood showed that Limnoria tunnels were concentrated at a depth of 2-3 cm from the timber surface, where creosote loading was lower. Fewer tunnels occured in the heavily creosoted outer zone. Sections through Limnoria tunnels in wood fixed on site were examined using the scanning electron microscope (SEM). These studies showed that S2 layers of wood cell walls adjacent to Limnoria tunnels were decayed by tunnelling bacteria in many cases. Examination of greenheart seals showed that Limnoria tunnelled to a depth of 1.5 cm, in the soft-rot decay zone. The heads of the Limnoria tunnels also penetrated "sound" wood to a depth of 2 cm. Examination of sections through Limnoria tunnels showed that wood cells adjacent to tunnels were decayed by both soft-rot fungi and tunnelling bacteria. In addition, a range of prokaryotes and protoctists were attached to tunnel walls in this instance. The size of bitemarks along the tunnel walls suggested Limnoria would ingest a range of these micro-organisms along with the wood substrate. Gut contents of Limnoria fixed at both sites were screened for microorganisms using the SEM. This study failed to show micro-organisms on the surface of wood particles during gut transit, which suggested that ingested microbes were digested by Limnoria.
A J Pitman, G S Sawyer, G F Daniel
The colonization of selected naturally durable timbers by marine fungi and borers
1977 - IRG/WP 439
In recent years, concrete and metal have been widely substituted for wood in contact with sea water, but wood products have not lost their usefulness under such conditions. In many cases, wood if sound and durable, may prove to be the most practical and economical of materials used in sea water exposure. Timber when immersed in the sea may be attacked by micro-organisms (bacteria and fungi) and marine borers (members of the molluscan genera: Teredo, Psiloteredo, Lyrodus, Bankia, Pholas, Martesia and others, also members of the crustacean genera: Limnoria, Paralimnoria, Sphaeaeroma and Chelura). Although marine borer damage is the more dramatic, damage by marine micro-organisms can contribute to cause soft rot of wood (Jones and Byrne, 1976), and they are also believed to be implicated in the 'preconditioning' of a wood surface prior to settlement of marine borer larvae (Eltringham, 1971). Ten tropical timbers (Mukulungu = Autranella congolensis, Moabi = Baillonella toxisperme, Angelique = Dicorynia guianensis, Jarrah = Eucalyptus marginata, Congotali = Letestua durissima, Azobe or Ekke = Lophira alata, Bilinga or Opepe = Sarcocephalus diderrichii, Douka = Tieghemella africana, Makore or Baku = Tieghemella heckelii, Wacapou or Acapu = Vouacapoua americana) were choosen to examine their natural durability in sea water in Italy, France, Ghana and Canada.
S E J Furtado, E B G Jones
The practice of using concrete on wood piling for marine use in Thailand
1982 - IRG/WP 492
The practice of using concrete on wooden poles has been carried on in Thailand for a long time in pile-houses and pier constructions which have been situated in, or partly in the sea. In such instances, the hewed round and/or square-sawn heartwood poles of naturally durable timber species have been coated with concrete of about 5 to 10 cm or more in thickness, and to about 100 cm above the highest tide level. Very durable species such as Xylia kerrii Craib & Hutch., Shorea obtusa Wall., Pentacme suavis A.DC., Hopea odorata Roxb., and Pterocarpus macrocarpus Kurz were used for such poles. They were well air-dried before the application and coated with a special mixture of concrete, which consisted of sand, crushed lime and stone, and cement powder which was used 1-2 times more than the concrete mixture used for general masonry. The performance of these poles treated in this way, as far as could be ascertained from the users, is about 15 to 20 years, or even more in some instances. Unfortunately it has not been possible to obtain exact data on the service life of these concrete-coated poles. Also palm trees have been used in sea-water without any treatment. The palm trees that have been used are Livistona saribus Herr., and Livistona speciesa Kurz. These have been used as piling for anchoring fishing boats to, because of their high elasticity and also as piles for supporting piers. They have given performances of more than 10 years of service. The outer parts of these trees are very strong and naturally durable to marine borer attack, but the inner parts of them are not resistant to decay fungi, although even though their inner parts have become rotted, they have remained strong enough for the above-mentioned purposes of utilization. If these palm trees are treated with suitable preservatives before being put into use, in order to protect them against the decay fungi, their service lives are much greater than those of untreated palms.
1983 - IRG/WP 1186
The micromorphology of decay in wood caused by a certain group of single-cell bacteria, called tunnelling bacteria (TB), is described. TB are characterised by their tunnelling ability within the secondary cell walls of wood fibres. Pure cultures of TB have not yet been obtained although the typical decay patterns can be reproduced using mixed bacterial cultures. Some indications of lignin degrading ability by TB have also been found. Laboratory studies indicate that TB are able to attack a wide variety of wood species which are more or less resistant against other forms of decay, either because of preservative treatment, chemical modification, high lignin content or presence of natural toxic extractives. Little information exist at present on the importance of TB for timbers in the field. Most reports are concerned with TB decay of wood in marine or fresh water environments.
T Nilsson, G F Daniel
Laboratory Evaluation of Soft Rot Resistance of Non-Durable Lesser-Known Malaysian Hardwoods
2006 - IRG/WP 06-10582
Resistance of six non-durable lesser-known Malaysian hardwoods, Pulai (Alstonia spp.), Rubberwood (Hevea brasiliensis), Ludai (Sapium spp.), Jelutong (Dyera costulata), Gaham Badak (Blumeodendron tokbrai) and Kayu arang (Diospyros spp.) compared with temperate Scots pine sapwood (Pinus sylvestris), were evaluated using the unsterile soil burial (mixed with Chaetomium globosum) versus vermiculite-burial (of C. globosum only) laboratory techniques and decay rates expressed as either percent mass/mass or percent mass/volume basis. Scots pine was expectedly soft rot resistant but Pulai wood was almost immune to decay. Other wood species varied from being moderately to highly susceptible to soft rot decay. The vermiculite-burial technique favoured greater soft rot degradation activity than unsterile soil-burial. Results also suggest that soft rot decay rates of susceptible woods could also be accelerated with higher surface area/volume ratios of test blocks. The use of mass/volume basis indicated similar reduced degrees of soft rot resistance among most test wood species whereas apparent differences among woods were found using mass/mass comparisons probably due to variable basic densities among these timbers.
A H H Wong
Errata in Document NO: IRG/WP/472
1981 - IRG/WP 483
L N Santhakumaran, J C Jain
Finishes for outdoor timbers
1975 - IRG/WP 378
Penichroa fasciata (Stephens) (Col. Cerambycidae) a pest in wood materials
1988 - IRG/WP 1365
Penichroa fasciata (Stephens) (Col. Cerambycidae) is found to be a frequent pest occurring in hardwood in storage in Italy. This paper reports the characteristic for identification, biological features, distribution and timber liable to attack.
A Gambetta, E Orlandi.
Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh
Natural durability transfer from sawmill residues of white cypress (Callitris glaucophylla). - Part 3: Full penetration of the refractory sapwood of white cypress
2000 - IRG/WP 00-40167
The heartwood of white cypress, Callitris glaucophylla, is renowned for its termite resistance and durability against decay. The sapwood, which can represent up to 30% of log volume, is non-durable and refractory to conventional preservative treatment. Previous work ascribes the lack of permeability to oily deposits within tracheids and ray cells. Environmental scanning electron microscopy was used to investigate ultrastructural aspects of sapwood permeability. Several pre-treatment processes to improve permeability were tested with limited success. Solvent drying allowed preservative penetration but damaged the structure of the timber. Neither, long term water soaking nor an oscillating pressure/vacuum cycle had any effect on porosity to water-borne treatments. Through extensive modifications to a standard VPI process we can now repeatedly achieve full penetration with organic solvent-based wood preservative solutions into white cypress sapwood. Effects of this process on the strength of the timber are being evaluated. Work is continuing as to the most effective and efficient treatment schedule and the latest results will be presented at IRG 31.
M J Kennedy, L M Stephens, M A Powell
Report on the monographic card on Coniophora puteana
1973 - IRG/WP 114
Problem of the treatment of dried sawn spruce building timbers with water-borne preservatives. Interim reports for discussion at the 4th Annual Meeting in West Berlin on 27 October 1972
1972 - IRG/WP 311
One of the most difficult technical problems facing the preservation industry is how to improve the treatment of refractory species of timber such as spruce. Its resistance to penetration, even under pressure' precludes its use for more hazardous service situations, and even in less severe conditions a higher level of treatment would be desirable. The importance of this subject led us to look once again at possible ways of improving treatment.
W Liese, J W W Morgan, T Hof, R O Ullevålseter
Monographic information on Lentinus lepideus.markup
1973 - IRG/WP 121
G Seehann, W Liese
The susceptibility of 35 Amazon wood species to Cryptotermes brevis (Walker)
1982 - IRG/WP 1160
Laboratory tests were carried to evaluate the susceptibility of 35 Amazon hardwoods to Cryptotermes brevis (Walker). The results were analysed statistically and showed that five wood species were non resistant, nine were resistant and the other twenty-one in between those classes of resistance.
M D Canedo
Some observations on Chlorophora pilosus Forst. var. glabromaculatus Goeze (Coleoptera, Cerambycidae)
1980 - IRG/WP 1119
Recent soft-rot research in softwoods and hardwoods
1980 - IRG/WP 1108
The purpose of this paper is to describe briefly the current status of our research on soft-rot fungi. The work to be discussed is still in progress and any results described must be regarded as provisional.
J A Butcher
The biostatic effect of copper on decay of fire retardant-treated mining timber
1991 - IRG/WP 1507
Blocks of Eucalyptus grandis were treated with 20kg/m³ ammonium sulphate as fire retardant and challenged with Coriolus versicolor. Replicates were soil buried. A second set of blocks was treated with retardant and copper at 6.6 kg/m³ (ie 1% w/w), and challenged similarly. After 8 weeks weight losses produced by Coriolus versicolor in untreated, retardant treated and copper supplemented blocks were 45, 25, and 0% respectively, and corresponding weight losses in soil were 27, 25 and 10%. These results, and electronmicroscopical observations, showed conclusively that Eucalyptus grandis treated with fire retardant was rapidly decayed, and that copper inhibited such decay.
G D Shelver, E A Shelver, A A W Baecker
Biological Durability of Laminated Veneer Lumber from Durable and Non-Durable Wood Species
2005 - IRG/WP 05-10567
Laminated Veneer Lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.
P Nzokou, J Zyskowski, S Boury, D P Kamdem
Feeding preference behaviour of Crytopermes cynocephalus Light and Coptotermes curvignathus Holmgren on twenty-eight tropical timbers
1985 - IRG/WP 1251
A study on the feeding preference behaviour of a dry-wood termite Cryptotermes cynocephalus Light and a subterranean termite Coptotermes curvignathus Holmgren on 28 species of tropical timbers has been conducted. The weight-loss of individual timber and the mortality of termite was·recorded after 5, 10, 15, 20 and 25 days of exposure. The results reveal that there are only five species among 28 species of wood which are completely repellent to both the dry-wood termite Cryptotermes cynocephalus and the subterranean termite Coptotermes curvignathus. These five wood species are Dalbergia latifolia, Eusideroxylon zwageri, Intsia bijuga, Lagerstromia speciosa and Tectona grandis. There are eight wood species which are repellent to Cryptotermes cynocephalus and seven wood species which are repellent to Coptotermes curvignathus. There are also only seven wood species which are completely arrestant or highly arrestant to both species of termite. Agathis alba and Mangifera indica are classified as highly arrestant to both the dry-wood and the subterranean termites. Other species are classified between moderately repellent to highly arrestant.
Untersuchungen über die Imprägnierbarkeit verschiedener türkischer Holzarten mit wirtschaftlicher Bedeutung
1976 - IRG/WP 370
Holzarten mit einer geringen natürlichen Dauerhaftigkeit können nur dann wirtschaftlich verwendet werden, wenn ihre Gebrauchsdauer durch einen zusätzlichen chemischen Schutz verlängert wird. Holzschutzmaßnahmen können nur regelmäßig geplant werden, wenn die Tränkbarkeit der verwendeten Holzarten bekannt ist. Aufgabe dieser Versuche war es daher, festzustellen, wieweit die Holzarten hinreichend getränkt werden können. In Rahmen der zur Zeit in der Türkei laufenden Entwicklungsvorhaben entstand die Frage nach den tränk-technischen Eigenschaften türkischer Holzarten, um ihre Verwendungsmöglichkeiten besser beurteilen zu können.
Scientific development for prolonging the service life of timbers by impregnating with creosote or organic solvent type preservatives in which additive has been incorporated
1977 - IRG/WP 382
Chemically impregnated wood has played a prominent part in the Telephone and Electricity Distribution Industry during the past century and there is no doubt that it will play an equally prominent part in the future. The reasons why wood poles and wooden, structures predominate, are that when adequately chemically impregnated with a recognised timber preservative to ensure the expected service life for the purpose envisaged, the timber is then fully protected against the ravages of wood destructive organisms. Furthermore, wood is endowed with many natural characteristics that make it a favourite pole and structural material. Its high strength, light weight, ability to absorb impact or shock from loads suddenly applied and ability to resist overloading for brief periods plus its well-known insulating qualities - all are important basic reasons for its predominance in pole line structure. The use of chemically impregnated timber often makes it possible to carry out a given construction programme at less cost, or to erect more structures for a given sum of money, than when more expensive construction materials are employed.
P R B D De Bruin
Data sheet on woodboring insects. 1. Bostrychus capucinus (Linnaeus)
1979 - IRG/WP 193
Monographic card for Stereum hirsutum
1973 - IRG/WP 119 E
Natural Resistance of timbers to marine borer attack. COIPM/IRG CO-OPERATION. Final report concerning panels exposed in the sea at Sekondi, Ghana
1979 - IRG/WP 449
The test was carried out according to Document COIPM/72.044, Revised procedure for the testing of naturally durable timbers against marine borers. The panels of the three species remaining in the test at the end of 1978 were removed and assessed visually. An average rating was given to the panels of each species.
F F K Ampong