Your search resulted in 370 documents. Displaying 25 entries per page.
Natural decay resistance of some lesser-used tropical hardwoods from Ghana
2002 - IRG/WP 02-10438
Ghana is a tropical African country that is rich in diverse timber species. In order to reduce over-exploitation of the popular timber species and increase the resource base for the wood industry, lesser-used or lesser-known timber species are being promoted locally and for export. To do this successfully, it is essential to determine the physical, mechanical and biological properties of these tim...
S A Amartey, F R Hanson
The use of modulus of rupture and modulus of elasticity in natural durability testing
1997 - IRG/WP 97-20117
Losses in weight, losses in bending strength and changes in elastic behaviour were assessed in a fungus cellar test with beech wood stakes (Fagus sylvatica). Results were gained after 8, 12, 16 and 20 weeks resp . The outcomes show, that the non-durable species beech is very rapidly attacked by fungi and loses up to 60% of its initial bending strength even within the first 8 weeks. Earlier researc...
L Machek, H Militz, W Gard
Natural exposure weathering tests: Their role in the assessment of wood preservative efficacy
1993 - IRG/WP 93-20006
Previous work has demonstrated the potential and usefulness of natural ageing procedures in e evaluation of wood preservative efficacy. This results from the combination of physico-chemical influences and microbiological interactions with both substrate and wood preservative. In this paper, results are presented for a range of biocide types. Discussions are centred on the value of natural exposure...
G R Williams, J Brown
Durability of Wood Plastic Composites Relative to Natural Weathering and Preservative Treatment With Zinc Borate
2005 - IRG/WP 05-40316
Wood-Plastic Composites (WPCs) used for decking have experienced dramatic increases in North America, averaging 25% growth per annum since 1998. A key factor contributing to this growth has been the successfully communicated message that they are "virtually maintenance free". The common perception being that the wood fiber is completely encapsulated by the thermoplastic resin, minimizing the pot...
M E Mankowski, F M Ascherl, M J Manning
Evaluating the natural durability of native and tropical wood species against Reticulitermes flavip
2004 - IRG/WP 04-10539
Environmental pressures to eliminate arsenate from wood preservatives has resulted in voluntary removal of CCA for residential applications in the United States. A new generation of copper organic preservatives has been formulated to replace CCA for decking and in-ground applications but there is no guarantee that these preservatives represent a permanent solution to all related problems. There...
R A Arango, F Green III, K Hintz, R B Miller
The influence of the natural extractives of opepe (Nauclea diderrichii) and African padauk (Pterocarpus soyauxii) timbers on their durability
1996 - IRG/WP 96-30098
Many timbers contain chemical extractives that undoubtedly play a key role in the timber's natural durability. Opepe (Nauclea diderrichii) and padauk (Pterocarpus sp.) are both very durable timbers (class 1), yet they are described as being moderately permeable. This suggests the presence of biocidal chemicals within these timbers, rather than simple blocking agents. Initial trials on the...
E D Suttie, R J Orsler
Improvement of some technological and biological properties of poplar wood by impregnation with aqueous macromolecular compounds
1992 - IRG/WP 92-3721
Poplars (Populus spp) belong to the most important tree species in afforestation programs of the Netherlands. Due to their rapid growth, the wood quality is usually low. Therefore, studies were performed to elucidate whether some technological properties and the resistance against fungal attack could be improved by impregnation with water-soluble resins. The results showed that swelling and shrink...
R D Peek, H Militz, J J Kettenis
Fungal-termite associations in the natural resistance of selected eucalypt timbers
1978 - IRG/WP 173
Butt billets of Eucalyptus regnans F. Muell., Eucalyptus grandis W. Hill ex Maiden, and Eucalyptus camaldulensis Dehnh., showing no visible signs of decay, were examined for the presence of fungi in outer, middle and inner heartwood. Fungi obtained in pure culture were characterized. Eucalyptus regnans yielded Cytospora eucalypticola van der Westhuizen, Trichoderma harzianum Rifai and Penicillium ...
D B A Ruyooka
Natural Durability of Tropical Species – Variations and Prospects
2005 - IRG/WP 05-10568
The tropical timber resources of the world play an unequivocal role in economic development of both the tropical timber producing and importing regions. This paper describes natural durability as an important and preferred wood quality of tropical species of the world with emphasis on Malaysian hardwoods, the link between various aspects of tropical hardwood durability, hardwood utilization and bi...
A H H Wong, Yoon Soo Kim, A P Singh, Wang Choon Ling
Marine exposure assessment of the natural resistance of a number of lesser known species of tropical hardwoods to teredinid and limnoriid borers
2004 - IRG/WP 04-10520
Naturally durable species of timber are used as an alternative to preservative treated timber for marine structures, but many species have not been evaluated for their potential for use in this environment. EN 275 specifies a 5-year test period - too long a period for screening tests to be economically viable. In this study, candidate timber species were selected for testing in the sea on the basi...
J R Williams, S M Cragg, L M S Borges, J D Icely
Soft rot decay of Belian (Eusideroxylon zwageri) wood
1995 - IRG/WP 95-10119
The heartwood of Belian (Eusideroxylon zwageri), an East Malaysian timber species, is naturally durable due to its certain unique anatomical features and high content of extractives. The timber can tolerate years of exposure to hazardous conditions in ground contact and other situations without any significant loss in its strength. A few Belian transmission poles sampled from one locality in Saraw...
A H H Wong, A P Singh
Termite resistance of Malaysian and exotic woods with plantation potential: Laboratory evaluation
1998 - IRG/WP 98-10280
The resistance of selected Malaysian woods to attack by the representative aggressive subterranean termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) was evaluated in four-week, no-choice laboratory tests. This is part of an ongoing effort between the Forest Research Institute Malaysia and the University of Hawaii to document the termite resistance of Malaysian timber species of po...
J K Grace, A A H Wong, C H M Tome
MDF manufactured from blends of cypress pine and radiata pine shows enhanced resistance to subterranean termite attack
2001 - IRG/WP 01-40214
Medium density fibreboards consisting of blends of the naturally durable wood species white cypress pine (Callitris glaucophylla) and non-durable wood species were manufactured in a commercial plant and subjected to a bioassay using the subterranean termite species, Coptotermes lacteus. A board composed of 30% cypress pine, 30% slash pine (Pinus elliottii) and 40% of the naturally durable hardwood...
P D Evans, S Dimitriades, C Donnelly, R B Cunningham
The natural durability of wood in different use classes
2003 - IRG/WP 03-10457
The natural durability of important European wood species has been tested on 3970 specimen in field trials. The wood was exposed at five test fields in Germany with different climates at each site in European hazard class 4 and 3 (with and without soil contact). Within EHC 3 it was distinguished between tree different expositions (end grain sheltered, unsheltered and with water trap).
The test is...
U Augusta, A O Rapp
Remedial treatments of glulam = diffusion of active ingredients through glue lines from solid wood diffusable preservatives
1996 - IRG/WP 96-30117
Diffusable preservatives are very suitable for use in remedial treatments of laminated beams in which too high moisture content involves the development of wood destroying fungi. The diffusion of active ingredients (boric acid, disodium octoborate, bifluoride) is well observed in solid wood but in a composite wood, the glue lines may appear not only as a barrier for the diffusion but also, may be ...
D Dirol, S Mouras
Assessment of wood decay in small-scale unsterile soil-bed tests
1997 - IRG/WP 97-20111
This study is concerned with the investigation of wood decay in small-scale unsterile soil-bed tests. Tests were performed with untreated heartwood samples from five hardwood species of different natural durability classes ranging from highly perishable to very resistant. Our results confirmed the critical role of soil moisture content on wood decay. The highest decay rates were observed at moistu...
L Machek, A M Derksen, R Sierra-Alvarez
The natural durability story
1997 - IRG/WP 97-20119
Wood species with superior natural durability were in use since the beginning of timber utilisation. Their importance decreased with increasing industrial timber impregnation. In recent time, however, they gained worldwide new interest due to environmental problems involved with treated timber. In Europe a special Standard (EN 350) has been published and a multinational research project on testing...
H Willeitner, R-D Peek
Durability of five wood species against Coriolus versicolor
1992 - IRG/WP 92-1578
The durability of following five wood species Zelkova carpinifolia, Ulmus glabra, Carpinus betulus, Acer trauvetteri and Pterocarya fraxinifolia were studied against Coriolus versicolor under laboratory conditions according to DIN 52176 standards. Zelkova caprinifolia shows a reduction in weight of 2.19%, Ulmus glabra 41.69%, Carpinus betulus 45.64%, Acer trauvetteri 53.05%, and Pterocarya fraxini...
S M Kazemi
Natural resistance of Bamboo (Bambusa sp.) to marine wood-borers in Goa waters (India)
1993 - IRG/WP 93-10032
The paper deals with the natural durability of Bambusa sp. against the attack of marine wood-borers in Goa waters. Test specimens of this species were completely destroyed within a short period of nine months due to severe attack of borers indicating its very low natural resistance. Wood-borers involved were Martesia striata (Linnaeus), Nausitora hedleyi Schepman and Lyrodus pedicellatus (Quatrefa...
L N Santhakumaran, S G Sawant
Comparing the resistance of a number of lesser known species of tropical hardwoods to the marine borer Limnoria using a short term laboratory assay
2003 - IRG/WP 03-10500
Naturally durable species of timber are used as an alternative to preservative treated timber for marine structures, but many species have not been evaluated for their potential for use in this environment. EN 275 specifies a 5-year test period - too long a period for screening tests to be economically viable. In this study, durability was assessed by measuring the production of faecal pellets by ...
L M S Borges, S M Cragg, J R Williams
Natural durability of 4 different Larix species tested in soil contact
2002 - IRG/WP 02-10434
Importers of Siberian Larch claimed to have a material which can replace pressure treated wood in soil contact. This gave reason to investigate the durability of 4 different Larix species (L. decidua, L. sibirica, L. decidua x sibirica, L. gmelini var ologenis) coming from 7 different origins in comparison with sapwood of Pinus sylvestris untreated as well as pressure impregnated with retentions o...
A O Rapp, H Viitanen, T Nilsson
Natural durability, density and extractive contents of 42 wood species of Bangladesh.
2003 - IRG/WP 03-10490
Natural durability, density and major extractive contents of 42 lesser used or unused wood species of Bangladesh have been studied. Correlation analysis between these properties has been performed. It has been shown that natural durability of these species neither explained by water soluble nor by alcohol benzene extractive contents. Density has a weak but significant positive correlation with dur...
S Akhter, K Akhter, S C Das
Resistance of various wood species against decay by Coniophora cerebella (Pers) Duby and Lenzites trabea (Pers) Bres
1976 - IRG/WP 142
Both fungi, Coniophora cerebella and Lenzites trabea, are important destroyers of timber. Coniophora often occurs inside buildings and Lenzites trabea has been observed on southern facades of buildings, on balconies and window frames. In most instances that we investigated coniferous timber had been decayed. But both species are known to attack also various hardwoods. For this reason tests similar...
O Wälchli
Natural progression of decay in unrestrained, Southern pine sapwood exposed above ground
1995 - IRG/WP 95-20060
In this study, the natural progression of decay is being monitored in 2.4-m (8-ft) lengths of dimension lumber. The 2.4-m lengths are supported without restraint in a horizontal plane approximately 0.75 m above ground in a partially shaded field plot in southern Mississippi. The lumber is 100% sapwood. Prior to installation in the field, each piece was planed to exactly 38 by 89 mm² (1.5 by 3.5 i...
R C De Groot, R J Ross, W Nelson
Some recent studies on the marine wood-borers of the west coast of India
1982 - IRG/WP 486
Occurrence and distribution of marine wood-borers along the west coast of India from Mangalore to Kandla are presented together with the distribution pattern of all the molluscan and crustacean wood-borers so far reported from India coasts. The survey, conducted for the first time along this coast, revealed the presence of 14 species of Teredinidae, 2 species of Pholadidae, 3 species and one varie...
L N Santhakumaran