Your search resulted in 37 documents. Displaying 25 entries per page.
Preference of swarming termites for various colored lights
1984 - IRG/WP 1238
The ability of the alates of the drywood termite Bifiditermes beesoni (Gardner) to discriminate ten different colored lights was studied. When an alternative choice of any of two colors was offered, the light-blue was preferred to all other tested colors by 97.7% of the alates. A lower degree of attractivity was found for some other colors and certain other colors were indistinguishable. Furthermore, the effects of light intensity and preconditioning to certain colors have been studied and finally the response of swarming alates from natural colonies is compared to that of the individuals from laboratory colonies.
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.
Light organic solvent preservative treatment schedules for New Zealand-grown radiata pine
1986 - IRG/WP 3379
The influence of pressure differential and treatment time on preservative uptake and distribution in radiata pine heartwood and sapwood is investigated. Treatment schedules are defined which minimise solvent usage but ensure complete sapwood penetration and optimise heartwood penetration.
Microscopic characteristics of Pinus radiata wood veneers weathered outdoors for one yea
1993 - IRG/WP 93-10018
Radiata pine (Pinus radiata) wood veneers glued to solid wood hacking strips were exposed outdoors at 45° north-facing for one year and then examined by light microscopy (LM) and transmission electron microscopy (TEM). As expected, the exposed wood surfaces were colonised by a variety of microorganisms; however, wood decay was not observed. Ultlaviolet (UV light) radiation and water were the main factors responsible for changes such as discolouration and the altered microstructure of wood cell walls which led to their disintegration. Cell wall discolouration observed under LM is due to UV light-induced breakdown in lignin, which may eventually disappear completely from some areas of the wood cell wall. The resulting increase in cell wall porosity was observable in the TEM. TEM was also used to identify the cause of failure of an oil-baised stain which was applied to one set of veneers before exposing them outdoors. The observations underscore the potential udefulness of a combined light and electron microscopy approach to study wood weathering.
A P Singh, R A B Sweeney, E A Dunningham, D V Plackett
Light organic solvent preservative treatment of glue-laminated radiata pine
1986 - IRG/WP 3380
The high permeability of radiata pine (Pinus radiata D. Don) is associated with ray-tissue and in particular the cross-field pits linking ray-tissue to tracheids. This pathway is absent in the tangential grain direction, leading to poor preservative penetration when treatment is restricted to the radial face - for example, timber fabricated into glue-laminated beams.
Conditions for basidiospore production in the brown rot fungus Gloeophyllum separium in axenic culture
1984 - IRG/WP 1232
Attempts to control and optimize the production of hymenial structures and basidiospore production in Gloeophyllum sepiarium in axenic culture resulted in the proposal of the following conditions as being suitable. The dikaryotic mycelia originally isolated from basidiocarps could consistently be induced to produce hymenial structures and pure basidiospore collects if illuminated by near ultraviolet light with emission maximum at 355 nm ("black light") at a temperature of 15°C on a chemically defined medium, where the concentration of the carbon and the nitrogen sources were shown to be of critical significance. The necessary conditions for basidiospore production in lignicolous fungi in general are is briefly discussed.
CCA fixation experiments. Part 1
1989 - IRG/WP 3504
A method of squeezing solution from CCA treated wood that has not been dried at various times after treatment appears to be useful in following the fixation of CCA in wood. Experiments confirm that temperature governs the rate of fixation.
W S McNamara
Water sprinkled pine wood: A microscope study on boards showing streaking
1993 - IRG/WP 93-10033
Boards sawn from the outer sapwood of pine lumber previously water sprinkled for periods of 10-18 weeks and kiln dried, showed streaking after staining. Two types of enhanced stain uptake were noted: 1) a more concentrated and localized form after 10 weeks and 2) a more diffuse type which developed in later stages of water sprinkling. Areas showing enhanced stain uptake were examined using light and scanning electron microscopy. For all samples, staining was most concentrated in rays (both fusiform and uniseriate) and axial resin canals. Studies suggest that increased permeability and enhanced stain uptake results primarily from microbial (fungal and bacterial) destruction of rays and axial resin canals (i.e. ray parenchyma, epithelia cells, window pit membranes), either by direct attack (i.e. close proximity of bacteria/fungal hyphae) or by diffusion of enzymes (probably cellulases) from microbes distant from sites of hydrolysis. Sapwood offcuts from the outer regions of water sprinkled wood lacking bark showed severe colonization and decay of ray tissues by both bacteria and sapstain fungi. Diffuse stain uptake in boards at later stages of water sprinkling appeared to be secondary and result from bacterial and/or fungal decay of bordered pit membranes.
G F Daniel, T Elowson, T Nilsson, A P Singh, K Liukko
Resin bleed after light organic solvent preservative treatment - the effect of drying method and process type
1986 - IRG/WP 3378
The effects of drying method and treatment process type on resin bleed were investigated. High-temperature drying of resinous radiata pine (Pinus radiata D. Don) heartwood resulted in improved wood permeability, higher preservative uptake, and greater resin bleed when treated by the Rueping process. Resin bleed was reduced substantially when timber was treated by the Lowry process, and totally eliminated when Bethell-treated. The incorporation of 2% wax into the preservative formulation may control resin bleed after Rueping treatment.
The Relationship of Fiber Cell Wall Ultrastructure to Soft Rot Decay in Kempas (Koompassia malaccensis) Heartwoo
2004 - IRG/WP 04-10541
The ultrastructure of fiber walls in kempas (koompassia malaccensis) heartwood was examined in relation to soft rot cavity formation. The fibers consisted of middle lamella and thick secondary wall. The secondary wall was differentiated in to a S1 layer, and a unique multi-lamellar S2 layer. Two distinct forms of lamellae were recognisable, one type being considerably thicker than the other. They also differed in their electron density, the thin lamellae being much denser than the thick lamellae. It was not possible to determine whether a S3 layer also existed, because of the presence of a dense material coating the lumen wall, which obscured the definition of this region of the fiber wall. The resistance to soft rot varied with different regions of the fiber wall, middle lamella being completely resistant and the thick S2 lamellae least resistant. The observed relationship between the ultrastructure of these fiber wall regions and the degree of their resistance/susceptibility to soft rot cavity formation is discussed.
A P Singh, A H H Wong, Yoon Soo Kim, Seung-Gon Wi
Effect of light and ventilation condition on the rate of wood decay by the brown rot basidiomycete, Tyromyces palustris
1991 - IRG/WP 1517
Effect of light and the ventilation conditions of incubation jars on the wood decay by Tyromyces palustris (Berk. et Curt.) Murr. FFPRI 0507 was investigated. Under no irradiation of light, the ventilation conditions gave extensive effect on mass loss of the test pieces when the culturing was performed with culture medium designated in Japanese Industrial Standard (JIS) A 9302 (Medium A; glucose 4.0%, malt extract 1.5%, peptone 0.3%). On the other hand, no such kind of effect for ventilation conditions was recognized under light conditions, and the wood decay by the fungus accelerated by additional light irradiation of a considerably small intensity. Next, we investigated the relationship between light and the culture medium composition during the wood decay by the fungus. It was found that almost equivalent mass loss occurred after 60-90 days of cultures when the culturings were performed under light-shield conditions with medium A, the culture medium designated in Japan Wood Preserving Association (JWPA) standard No.1 (medium B; malt extract 2.0%, peptone 1.0%), and another culture medium diluted medium B by two times (medium C). Under the irradiation of light, the mass loss on the cultures in medium B and C was markedly less than that in the same media under no irradiation conditions. These results suggested that effect of light on the wood decay by Tyromyces palustris depended on the concentration of glucose in the culture medium. Further, we also investigated the activities of several extracellular and cell wall bound enzymes in wood meal medium contained medium A. From our experimental results, the activities of cellulase (b-1,4-glucan 4-glucanohydrolase, E.C. 184.108.40.206) and mannanase (b-1,4-mannan mannanohydrolase) depended on light irradiation during the wood decay and these enzyme activities may give extensive effect on the mass loss by Tyromyces palustris.
T Suzuki, M Higaki
Ultrastructure of degraded, CCA-treated Pinus radiata wood from a marine pile
1990 - IRG/WP 1461
During an inspection of marine piles, 12 years after installation, severe degradation was noted on one of them in the vicinity of a corroded eye-bolt. The wood was dark brown in colour and tended to crumble easily. Wood fragments were examined by light microscopy and scanning and transmission electron microscopy and were also analysed for carbohydrates and lignin. Light microscopy showed numerous cracks in tracheid walls resulting in delamination at middle lamella - S1 and S1 - S2 junctures and also in fractures across the tracheid wall. Chemical analysis showed extensive losses in hemicelluloses and also losses in cellulose. Observations with polarised light microscopy supported the data from chemical analysis on cellulose degradation. Although presence of microbial flora in the lumen of wood cells was revealed by scanning electron microscopy, transmission electron microscopy showed only occasional soft rot decay zones in the S2 layer. We suggest that the degradation of Pinus radiata wood cell wall is primarily due to chemical attack, fungal decay playing a minor role.
A P Singh, M E Hedley
EELS (Electron Energy Loss Spectroscopy) - a technique for quantification of nitrogen and other light elements in the cell wall
1999 - IRG/WP 99-20163
A literature survey was performed to find progress in techniques for monitoring penetration of synthetic resins in wood cell walls. Electron energy loss spectroscopy (EELS) in combination with transmission electron microscopy (TEM) was successfully applied for the high resolution examination of the distribution of a partly methylated hydroxymethyl melamine resin in Norway spruce (Picea abies Karst.) earlywood cell walls. The nitrogen of the resin was found as clearly detectable signals in all layers of the lignified cell wall, thus allowing the quantification of resin which had penetrated into the different layers.
A O Rapp, H Bestgen, W Adam, R-D Peek
Variation in infection rates of blue-stain, mould and white rot tropical fungi on mixed light Malaysian woods
2000 - IRG/WP 00-10334
The modified 3-week FRIM laboratory method for screening of anti-sapstain formulations against three representative tropical fungi causing blue-stain (Botryodiplodia theobromae), mould (Paecilomyces variotii) and white rot (Schizophyllum commune) infection of sapwood species was used to examine the relative resistance of the sapwood of eight mixed light Malaysian woods, Scots pine (Pinus sylvestris), medium density fibreboard produced from Rubberwood (Hevea brasiliensis) and the heartwood of Sentang (Azadirachta excelsa), to infection by these organisms. After 21 days it was found that Ramin (Gonystylus spp.), Rubberwood, Mersawa (Anisoptera sp.), Ludai (Sapium spp.), Yellow meranti (Shorea spp.), Scots pine and Jelutong (Dyera costulata) were highly susceptible to the pooled combinations of blue-stain, mould or white rot infection often sustaining >50% overall mean fungal coverage or when at least one of the infection types has reached maximum mean coverage (75.5%) of the wood samples. However, the Rubberwood-based fibreboard, and particularly Sentang, and the softwood Agathis spp. from Kelantan (trade name: Damar minyak) and Sarawak (trade name: Bindang), were relatively moderately susceptible to infection, sustaining between 9 and 47% overall mean fungal coverage after 21 days, or even considerably less susceptible (5 - 20% overall coverage) after 14 days. There was absence of both blue-stain and white rot fungal growth on all samples dipped in a low (0.03%/0.03%) fungicide concentration of a MBT/TCMTB anti-sapstain formulation. Such laboratory test results could have significant implications to field or industrial sapstain control of sapwood timbers concerning the lag time between tree felling and anti-sapstain treatment and seasoning.
A H H Wong, S Ahmad
Laboratory tests on light organic solvent preservatives for use in Australia. - Part 6: Soft rot resistance of three fully formulated preservatives on different timber substrates
2000 - IRG/WP 00-30245
The above-ground soft rot resistance of substrates treated with three fully formulated light organic solvent preservatives (Cuprivac Green WR, Impresol WR 205 and Vacsol) was studied using a modified vermiculite burial method. The substrates were sapwood of Pinus elliottii and P. radiata and heartwood of Eucalyptus regnans, Pseudotsuga menziesii, Shorea sp. (a lower and a higher density source) and Thuja plicata. Following artificial weathering, replicate test blocks were exposed to either Chaetomium globosum or Lecythophora mutabilis. C. globosum caused 3% or more mass loss of the water and solvent (white spirit) impregnated controls of all three hardwoods and two of the four softwoods, whereas L. mutabilis caused similar attack in only E. regnans and P. radiata. The P. menziesii and T. plicata heartwoods were naturally durable to both soft rot fungi and, hence, no further conclusions can be drawn. None of the preservatives, at the highest retention tested, protected E. regnans from attack by C. globosum, whereas the highest retentions of both the Cuprivac Green WR and Impresol WR 205 protected all other timbers from this fungus. At the highest retention, the latter preservative was the only one to protect E. regnans from L. mutabilis.
G C Johnson, M A Tighe, J D Thornton
Longterm monitoring of termite activity on multiple feeding sites: a laboratory method intended for the determination of attractant/repellent properties of wood preservatives and baits
2001 - IRG/WP 01-20225
A method is introduced allowing the continuous monitoring of the activity of a small laboratory termite- colony at 8 different feeding sites simultaneously. The test assembly consists of a small central polycarbonate-tube containing a colonie of Reticulitermes santonensis (de Feytaud) beeing connected with 8 external feeding sites by small glass-capillaries. The termites passing through the glass capillaries to and from the feeding sites are interrupting an infrared light-barrier. Each signal from the light-barriers is conditioned and fed to a PC-based signal-recognition-, monitoring- and storage-system. First results show that a colony of 500 individuals of Reticulitermes santonensis (de Feytaud) will need approx. 2 to 3 weeks for establishing a new, full functional hierarchy. A well established Reticulitermes- colony will show 80 to 100 passings per minute to and from the eight feeding sites. The activity of Reticulitermes santonensis (de Feytaud) shows no circadian activity rhythmic.
M Pallaske, E Graf, H Takiuchi
A technique for fructification and basidiospore production by Serpula lacrymans (Schum. ex fr.) SF Gray in artificial culture
1986 - IRG/WP 2255
A method for fructification and basidiospore production by Serpula lacrymans is outlined. A wheat flour/malt extract medium or an oat grain medium, enriched with alanine, tri-potassium phosphate and thiamine supported good fructification of the fungus at a temperature of 12°C. The influence on fructification of temperature, light and inoculum is discussed. To date, 22 stains from a total of 38 tested, fructify in culture.
S Cymorek, B M Hegarty
A light and electron microscopic study of decayed CCA-treated radiata pine (Pinus radiata) wood from a cooling tower
1994 - IRG/WP 94-10056
An inspection of an industrial cooling tower in New Zealand showed surface decay of 12 year old Pinus radiata wood panels treated with CCA preservative to a retention of around 15 kg/m³ of salt. Wood decay micromorphology typical of that caused by soft rot fungi, white rot fungi, 'stripy' and 'v-shaped' erosion bacteria and cavitation bacteria were all commonly seen using a light microscope (LM). Some evidence of the presence of tunnelling bacteria was also seen but was not as common. Soft rot was largely absent from the wettest regions sampled such as spray-line supports and side panels in close proximity to the spray lines, and erosion bacteria attack was the predominant type in these areas. Transmission electron microscopy (TEM) showed that unusual patterns largely consisting of troughs, depression and granulations in wood cell walls, were in most instances, almost certainly caused by erosion bacteria, but in others, tunnelling bacteria were also present. Several decay patterns seen under light microscope as matrices of fine troughs parallel and perpendicular to the cellulose microfibres were difficult to characterise in terms of previous classification but were also thought to have been caused by erosion bacteria. The distinction made by previous classification between patternms formed by erosion and cavitation bacteria needed to be questioned on the basis of observations made. Whilst the TEM showed that erosion and tunnelling bacteria were often present in close association within the wood cell walls, light microscopy suggested that, in the majority of section examined, all the types seen were clearly seperated by regions of undegraded cell wall. The observations underscore the importance of erosion bacteria in wood decay under the conditions of a cooling tower where in-service timbers are kept constantly wet by the spray from water sprinklers. Also of significance is the great diversity of decay types seen, in particular the presence of cavitation bacteria and white rot fungi has not previously been recorded for high retention CCA treated cooling tower timbers.
A P Singh, R N Wakeling, D R Page
Distribution of copper/chrome/boron preservative in light red meranti (Shorea leprosula) before and after exposure test for 72 months
1995 - IRG/WP 95-20073
Copper/chrome/boron (CCB) preservative at 6% w/w was impregnated into light red meranti (Shorea leprosula) by full cell process. The quantitative analysis for copper, chrome and boron contents in treated wood samples was carried out by Inductive Couple Plasma (ICP). Electron Probe Microanalyser (EPMA) was used to monitor the distribution of copper, chrome and boron in the various treated wood tissues before and after exposure for 72 months.
S Salamah, S Ani
A technique for the rapid assessment of wood surface degradation during weathering
1987 - IRG/WP 2281
Radiate pine (Pinus radiata D. Don) sapwood samples taken from four trees were converted into thin strips 100 x 10 x 0.085 (85 µm) mm³, (longitudinal x radial x tangential) in size and exposed in preweighed hatches to the weather inclined at 45° facing equatorially for 10, 20, 40, 60, 80 and 100 days. Significant (P < 0.001) weight losses occurred with time over the exposure period. Differences between samples were non significant. Chemical analysis indicated a progressive increase in surface solubility resulting in significant losses of polysaccharides and lignin.
P D Evans, D Abbott, S Thein
Basisiospore production by Lentinus lepideus in vitro
1987 - IRG/WP 2276
Evaluation of fungicides active against the lower fungi by spore based bioassays is very common. Possibilities of using similar assays to evaluate preservatives against brown rot and white rot fungi, especially for use in above ground constructions, are limited by the lack of methods for production of basidiospores. Tested media containing glucose 10-30 g/l and ammonium tartrate concentrations 2-20 g/l supported fairly good spore production. Media buffered with the organic buffer 2 (N-morpholino) ethane sulfonate (MES) with phosphate concentrations of 12.5-50 mM supported good spore production.
Fruitbody formation and basidiosporogenesis by the white rot fungus Pycnoporus cinnabarinus
1988 - IRG/WP 1348
Conditions for fruitbody formation by the white rot fungus Pycnoporus cinnabarinus in vitro were outlined. A marked difference in substrate requirements in comparison to previously tested brown rot fungi was revealed. Agar media containing Walseth cellulose and NH4 tartrate at 1 g/l permit profound production of basidiospores particularly at 15°C but only under light treatment. Higher NH4 tartrate concentrations and glucose addition slowed down or inhibited the fruitbody formation. Axenic basidiospores, to be used in tests for inhibitors contributing to natural durability, as well as in tests for fungicides could thus be produced.
The use of light organic solvents in industrial wood preservation - an environmental perspective
1995 - IRG/WP 95-50040-22
The paper examines the evolving regulatory environment concerning the use of hydrocarbon solvents in industry and, in particular, the European wood preserving sector. The implications of the proposed EU Directive on industrial solvent use are explained and possible responses to such regulation examined, including process modification, product changes and emission abatement, where necessary. The development of new solvent recovery technology for the wood preservation sector, as one response, is described in some detail.
G A Ewbank
Wood durability in the light of recent trends and research on the durability of building materials and components
2000 - IRG/WP 00-20195
Building-related research of today demonstrates a clear shift in focus from the design and production phases to usage and to the entire life time. A consequence is that the performance criteria of materials, components and of the entire building must be regarded over the life time rather than at the time of production or delivery. As one example can be mentioned the Building Construction Directive of the European Union were a number of essential requirements on buildings are stated. These requirements relate i. a. to safety and environment issues and are to be regarded as highly non-controversial. However, it is clearly stated in the Directive that these requirements must be fulfilled during the entire lifetime of the building. This means that the performance-over-time of each single material must be known and that a careful life time planning of the building must be introduced in the design and construction phase of the building project. To make this possible a lot of research is necessary and the research activity in this field is high. State of the art is presented every second year at the International Conferences on the Durability of Building Materials and Components, latest arranged in Vancouver in May 1999. In this paper the wood based and in special the chemically treated materials are discussed from the point of view of modern durability research approaches. The interaction between durability and environmental impact in a live cycle perspective is mentioned. A conclusion is that the research within IRG should be focused more on different building applications than has been the case so far. Examples of possible and necessary research projects are given.
Decomposition of biocides in aqueous media cases of MTC and TCMTB
1993 - IRG/WP 93-50001-26
Our laboratory is interested in the fate of modern biocide molecules in the environment. Here we present recent work which has been done on the fate of two compounds with fungicidal and bactericidal properties: methylenedithiocyanate (MTC: NCS - CH2 - SCN) and thiocyanomethylthiobenzothiazol (TCMTB). We have studied separately the influence of pH, temperature and ultraviolet irradiation in aqueous media. The results show that the higher the pH (the more basic) and the higher the temperature, the easier these biocides decompose, liberating other compounds, essentially cyanide and thiocyanate ions CN¯ and SCN¯ along with organic decomposition products, namely mercaptobenzothiazole in the case of TCMTB and a thioamide and a diamine in the case of MTC. Moreover, for both of the biocides, we have noticed shown both in the aqueous phase and in the gazeous phase bordering the aqueous phase the formation of CS2 and a sulfur containing heterocyclic compound, i.e. 1,2,4 - trithiolane. The photochemical decomposition of TCMTB (between 350 and 700 nm) in water as such and in presence of traces of H2O2 is significant for long exposition times. In both cases we noticed the formation of mercaptobenzothiazole. On the other hand, MTC is not decomposed in this wavelength interval.
R Perraud, M Papazian