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The use of pressure cycling to improve heartwood penetration in Pinus radiata (D. Don)
1995 - IRG/WP 95-40050
This study investigates the effect of cycling pressure on the treatability of radiata pine heartwood. The results indicate that liquid penetration into the heartwood is affected by the preconditioning method used and pressure treatment time. There is no significant improvement in the penetration of Pinus radiata (D. Don) heartwood when a cycling or pulsation process is used.
P R S Cobham, P Vinden

Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)
2005 - IRG/WP 05-30373
The chemistry analysis of the compounds present in dichloromethane and ethanolic fraction as well as bioassays enables to understand the durability differences of Eperua falcata and Eperua grandiflora. The principal distinction between these two species is the acidic subfraction of diterpenoic extract, which is antifungic in Eperua falcata when tested in in-vitro conditions. This study also enables to show that ethanolic fraction plays an important role in the mechanism of natural durability. It also reports the first isolation of cativic acid in Eperua falcata wood.
N Amusant, C Moretti, B Richard, E Prost, J M Nuzillard, M-F Thévenon

Effect of a penta emulsion on the service life of Douglas fir, heartwood posts
1978 - IRG/WP 3112
C S Walters

An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper-chrome-arsenic preservative
1981 - IRG/WP 3150
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. We have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins

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.
P Vinden

Efficacy of some extractives from Pinus heartwood for protection of Pinus radiata sapwood against biodeterioration. Part 1: Fungal decay
1995 - IRG/WP 95-30072
Chemical compounds thought to contribute to the natural durability of heartwood of Pinus spp. were either chemically synthesised in the laboratory or extracted from the heartwood of Pinus elliottii or Pinus caribaea. These compounds included the stilbenes, pinosylvin and its mono- and di-methyl ethers, and the flavonoids, pinobanksin and pinocembrin. Small blocks of Pinus radiata sapwood were impregnated with methanolic solutions of pure compounds or heartwood extracts, to a range of retentions extending above and below the concentration of each compound known to occur in the heartwood of Pinus spp.. Fungicidal efficacy of these compounds has been evaluated by exposure of treated blocks to pure cultures of a white and a brown rot, in addition to an unsterile soil test.
M J Kennedy, J A Drysdale, J Brown

Analysing the characteristic role of moisture content for drying and fluid flow in Sitka spruce. - Part 1: The drying process of sapwood and heartwood of two different thickness of Sitka spruce using a kiln. - Part 2: Effects of moisture content on longitudinal permeability of Sitka spruce in vertical variation of the tree
2000 - IRG/WP 00-40173
The characteristic role of the moisture content in Sitka spruce (Picea sitchensis (Bong.) Carr.) that grown in the United Kingdom was examined by this study on the basis of (1) the reduction of moisture content in two different thickness of sapwood and heartwood by kiln drying process, and (2) the effects of moisture content to the longitudinal void volume filled of tanalith-C by the full-cell process from base (1 m) to apex (3 m) of the tree in sapwood zone. Accordingly, conclusions on indication of the drying process of sapwood and heartwood, and vertical variation of longitudinal flow with effects of moisture were listed separately: (1) Comparison of Drying Characteristic of Sapwood and Heartwood: The two different thickness (300x30x30 mm3 and 300x20x20 mm3) of sapwood and heartwood of Sitka spruce was dried using the suggested drying schedule in kiln. The reduction of moisture was schematically diagrammed according to sapwood and heartwood stakes. The reduction of moisture followed the same downward trend that sapwood (S) loses more moisture than heartwood (H) although the small stakes of S and H lost moisture rapidly compared with the large ones. (2) Vertical Variation of Moisture Content and Longitudinal Permeability: The 90 kiln dried defect free sapwood stakes (150x25x25 mm3) of Sitka spruce was taken from base to apex of the trees at 1, 2 and 3 m above ground level. After having the determination of moisture content in each experimental stake, the treatment was carried out by the full-cell process with CCA preservative (Tanalith-C) using a model pressure treatment plant. Significant differences observed among the tree heights from 1 to 3 m showing that slightly increases of moisture content from base to apex and conversely decreases of longitudinal void volume filled by preservative fluid.
I Usta

Possibility of use of wood species per class of biological risks. Attempt to determine criteria based on Pr EN 350-1/2/3
1992 - IRG/WP 92-2409
M Rayzal

Treatment of Douglas fir heartwood with disodium octaborate tetrahydrate (Tim-BorÒ ) to prevent attack by the Formosan subterranean termite
1991 - IRG/WP 1487
Toxicity of disodium octaborate tetrahydrate (Tim-BorÒ) to Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), and termite feeding on treated Douglas-fir heartwood were evaluated in laboratory and field tests. Feeding on filter papers impregnated with Tim-BorÒ solutions reduced but did not eliminate termite gut protozoan populations. In a forced-feeding laboratory assay, Douglas-fir heartwood treated to Tim-BorÒ retentions ³0.35% BAE drastically reduced termite feeding and resulted in 100% termite mortality within three weeks. Gradual and significant mortality (49%) after four weeks of feeding at 0.16% BAE suggests that this or lesser concentrations may be useful in baits for remedial termite control. After 162 days of field exposure to an active Coptotermes formosanus colony in an accelerated field test, moderate feeding was noted at 0.65% BAE (13.6% weight loss) and 0.73% BAE (16.9% wt. loss), and only slight damage (2.5% wt. loss) at the highest retention field tested of 1.02% BAE. These results indicate that Tim-BorÒ provides protection from Formosan termite attack, but that some cosmetic damage occurs even at high retentions. This cosmetic damage is unlikely to create a structural hazard, but additional field evaluations are needed to determine the treatment requirements for timbers visible to the consumer.
M Tamashiro, R T Yamamoto, J K Grace

Estimation of service life of durable timber species by accelerated decay test and fungal cellar test
2002 - IRG/WP 02-20249
Many kinds of durable wood species for outdoor uses has been imported from all over the world to Japan. However information on the natural durability of these species is not sufficient to estimate the service life of them in the climate of Japan. Highly durable species such as Jarrh, Teak, Ipe, Ekki, Selangan batu, Red wood, Western red cedar showed no significant percent mass losses by accelerated decay test according to the JIS Z2101, but some of them are degraded during fungal cellar test for 4 years . The decay rating (0:sound to 5:totally decayed) of them after 4 years exposure was 1.0, 2.0, 0.0, 1.0, 0.0, 2.3, 5.0 respectively. This results indicated that the conventional accelerated decay test could not evaluate the natural durability of these highly durable species at all. Solid wood specimens treated with boiling water at 120? for one hour are subjected to the same JIS test, and the obtained percent mass losses of these species are 1.2, 2.9, 1.9, 3.8, 4.7, 17.5, 0.0 % by a brown rot fungus, Fomitopsis palustris, and 17.5, 14.3, 3.3, 8.2, 4.2, 0.0, 18.3 % by a white rot fungus, Trametes versicolor respectively. Pre-treatment of solid wood specimens for removal of heartwood extractives before a accelerated decay test would be an effective way to evaluate the natural durability of highly durable species in a laboratory.
K Yamamoto, I Momohara

CCA component distribution in the heartwood of treated lodgepole pine and white spruce
1998 - IRG/WP 98-30173
As part of a comprehensive study on the influence of drying on heartwood permeability, the distribution of copper, chromium and arsenic (CCA) in lodgepole pine (Pinus contorta Dougl.) and white spruce (Picea glauca (Moench) Voss.) heartwood was examined with light microscopy. Stained microtomed sections were examined to determine the penetration pathway for the CCA. The microscopic observations revealed clear differences in the distribution of the various components in the various cells in the CCA treated wood, particularly those associated with ray cells and resin canals. At the limit of CCA penetration, it was clear from the intensities of the staining in the section, that the ray cells and resin canals were primary avenues solution penetration to the tracheids. Higher levels of components of CCA were observed associated with the resin canals and ray cells than with the tracheids.
Y An, J N R Ruddick, P I Morris

Innovations in the treatment of Southern pine heartwood
2000 - IRG/WP 00-40172
Whereas the sapwood of southern yellow pine (Pinus spp.) is readily treatable, the heartwood is essentially impermeable to preservatives such as chromated copper arsenate (CCA). Preliminary studies at the Mississippi Forest Products Laboratory indicate that increases in penetration and retention of preservative in pine heartwood can be obtained by subjecting kiln dried dimension stock to varying mechanical stresses using the patented TASK Process machine. The TASK Process machine incorporates varying levels of compression and/or vibration to mechanically stress lumber.
M G Sanders, T L Amburgey, H M Barnes

Fungi associated with groundline soft rot decay in copper/chrome/arsenic treated heartwood utility poles of Malaysian hardwoods
1992 - IRG/WP 92-1567
Copper-chrome-arsenic treated heartwood from Malaysian hardwood utility poles in service for 8-23 y at two localities in the wet tropical Peninsula Malaysia were surveyed for soft rot in the ground-contact region. Soft rot decay was detected in all the poles. Isolation studies indicated the ability of a variety of microfungi and basidiomycetes to colonize treated heartwood. Most isolates exhibited variable soft rot ability based on a combination of soft rot tests. A few of the isolates formed soft rot cavities (decay types 1 & 2) and belonged to genera previously found associated with soft rot decay. In particular, isolates of Chaetomium globosum and Phialophora occurred frequently on the surface of sampled poles, while Paecilomyces variotii occurred at all sampling depths from the wood surface. It appeared that soft rotting ability of selected isolates (determined from both mass loss and dilute alkali solubility of degraded native cellulose) was affected by the choice of incubation temperatures.
A H H Wong, R B Pearce, S C Watkinson

The influence of age on retention and fixation of CCA in pressure-treated Kenyan-grown Eycalyptus saligna: Summary of findings
2002 - IRG/WP 02-30296
The present study investigates the influence of age on retention and fixation of copper-chrome-arsenate (CCA) in Kenyan-grown Eucalyptus saligna. Samples for the study were obtained from sound trees aged 4, 8, 12, 16, 20 and 24 years. Test samples were radially cut from round material to represent total sapwood and heartwood for each age class, and measured 50mm in thickness, 100mm long, with widths varying according to the radii of the pieces. The samples were air-dried to an average of 15% moisture content, end-sealed, and treated at a commercial pressure treatment plant with 6% CCA-C (oxide type). They were subsequently conditioned for 6 weeks, air-dried to 15% MC, leached in running tap water for 9 days, re-dried to 15% MC, retentions calculated and results analysed. The results indicated a decreasing trend in retention with increasing age, but substantially higher fixation of the preservative was achieved in samples from older than younger trees. Samples from 4-year old trees with wider sapwood bands achieved consistently higher initial retentions (31.4Kg/M3) compared to those from 24-year old trees with narrower sapwood bands (9.4Kg/M3). However, losses through leaching were higher in samples from younger trees, 14.5Kg/M3 (46.2%) in 4-year old trees, compared to 0.8Kg/M3 (8.5%) in 24-year trees. It was also noted that both retention (31.4 -28.6Kg/M3), and percentage losses of CCA through leaching (46.2-41.6%), were higher in samples from trees between 4 and 8 years, but markedly decreased in samples from trees of between 20 and 24 years, 12.8-9.4Kg/M3 and 10.2-8.5% respectively. Fixation of CCA proved to be low in samples from younger trees, 53.8% and 58.4% for 4 and 8-year old trees respectively, but substantially higher, 89.8% and 91.5%, in samples from 20 and 24-year old trees. Treated eucalyptus poles and posts in the country are invariably from younger trees, and the recommended CCA ground contact retention of 18.0Kg/M3 for pressure treatment may not be adequate.
R Venkatasamy

Decay resistance of Scots pine (Pinus sylvestris) heartwood against brown rot
2002 - IRG/WP 02-10433
Natural decay resistance of wood is mainly restricted in the heartwood and based on wood microstructure and chemical composition. The genetic variation in the durability of Scots pine (Pinus sylvestris L.) wood against decay and the relationship between resistance and chemical composition was studied. The laboratory tests of 6 and 8 weeks were carried out with a brown rot fungus Coniophora puteana (Schum. ex Fr) Karst (strain Bam EBW 15). The increment core samples of sapwood and juvenile heartwood, obtained from about 30-year-old half-sib progenies, were decayed using a modification of the standardised EN 113 method. The average density of the sapwood was 391 mg/cm3 (one stand) and that of heartwood samples 337 and 376 mg/cm3 (two stands). The average mass loss of the sapwood samples was 114 mg/cm3 (6 weeks, stand 1) and that of the heartwood samples 80 mg/cm3 (6 weeks, stand 1) and 123 mg/cm3 (8 weeks, stand 2). The variation among heartwood samples was high. The additive genetic component was small in stand 1 but quite large in stand 2, which resulted in a low narrow sense heritability h2 in stand 1 (0.07) but high in stand 2 (0.37). New samples were taken from the most resistant and susceptible trees for chemical analyses. The concentration of resin acids was higher in the group of decay resistant trees than in the group of decay susceptible trees. About 90 % of the resin acids in the heartwood were of the abietane type, abietic acid being the most abundant.
H Viitanen, A M Harju, P Kainulainen, M Venäläinen

The effect of selective additives and conditions on the decomposition of Basamid in Douglas fir heartwood
1992 - IRG/WP 92-3698
Basamid is a solid, powdered chemical used as an agricultural soil fumigant. Decomposition of Basamid isothiocyanate, hydrogen sulfide, methyl amine, and formaldehyde. Basamid has some potential as a wood fumigant, but it decomposes too slowly to be effective. Various additives and conditions were tested for their ability to enhance Basamid decomposition in Douglas-fir heartwood. Higher MC's and temperature, as well as copper sulfate and powdered pH 12 buffer increased decomposition rates with copper increasing the efficiency of breakdown to form MITC.
P G Forsyth, J J Morrell

Safer alternative reagents for colour differentiation of heartwood and sapwood
1994 - IRG/WP 94-20028
Benzidine and dimethyl yellow reagents have been used for distinguishing heartwood from sapwood in the Pinaceae and Araucariacae families, and in Eucalypt species. Both have been classified as carcinogenic by European and United States authoritites, yet the need for effective heartwood/sapwood differentiation remains, not only in the laboratory but also out in the timber processing chain. Safer alternative reagents have been proposed over the past twenty years, but some of these have since been linked with health problems, and most of the rest lack the specificity and general usefulness of those traditionally used. Recent research has investigated various azo, diazo, and other nitrated reagents. Safe but useful alternative methods of sapwood/heartwood differentiation are being established, and recommendations are made for several timber species.
A Zosars, M J Kennedy

Ekki heartwood - is “Durable”
2002 - IRG/WP 02-10444
Severe decay damages of bridges made of ekki (Lophira alata Banks) wood which is classified as a durable species in the EN 350:2 as already reported at the 31 IRG annual meeting. This paper deals with results of long-term decay tests of ekki heartwood specimens using 3 isolates (Loweporus tephroporus 2 strains and a fungus of other sp. from damaged ekki bridges) and Trametes versicolor as a reference. Sound ekki heartwood specimens, sized 20(T) x 20(R) x 5(L) mm were used. References were Japanese beech (Fagus crenata) specimens having the same dimensions. Oven dry weights of the specimens were measured at 60 oC for 48 h before and after the decay process. Nine replications of specimens were used per set. The procedure of decay test was about the same as that of the JIS Z 2101. All the test fungi including T versicolor decayed ekki heartwood in the case of long-term exposure (more than 6 months) using the appropriate nutritional condition under optimum temperatures. These facts suggest that the results of standardised decay test methods should be carefully interpreted.
S Doi, R Itoh, S Horisawa

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

Observations on the uptake and penetration of various liquids in clear heartwood and sapwood of Pinus radiata D.Don
1983 - IRG/WP 3224
Volumetric uptake of water (aqueous copper-chrome-arsenic (CCA)) or methanol, applied by bulk hydrostatic pressure to air dried clear heartwood specimens of Pinus radiata D. Don, far exceeds that of a wide variety of polar and non-polar solvents. In air dried sapwood, the volumetric uptake of CCA tends to be less than that achieved for most solvents including methanol. No comprehensive explanation of the penetration mechanism in these two substrates can yet be offered. High temperature drying effects a significant increase of volumetric uptake of all liquids by heartwood, but not by sapwood, possibly because air dried material is nearly saturated after pressure treatment.
J E Barnacle

Leaching of copper, chromium and arsenic from CCA-treated slash pine heartwood
1994 - IRG/WP 94-50020
Drying green slash pine with any of three high temperature drying schedules produced a product in which both the sapwood and the heartwood could be penetrated with CCA using a modified Bethell treatment schedule. Required H3 retentions were achieved in both sapwood and heartwood, from 200 litres per m³ charge uptake. Post-treatment fixation/drying was accomplished by three different regimes, including an accelerated fixation. Although acceptable preservative penetration and retention was achieved in the heartwood, arsenic fixation (as determined by both AWPA procedure E11-87 and U.S. EPA TCLP procedure) was inferior to that attained in the sapwood. TCLP leachates from 1 cm³ heartwood blocks contained up to 4.5 mg/l arsenic, very close to the maximum value (5.0 mg/l) currently permitted in Australia for arsenic waste disposal. Though there are clear advantages in achieving heartwood penetration, caution must be exercised to ensure that this step does not compromise the accepability of the product. No process modification could be accepted if it introduced possibilities of exceeding safe disposal limits for sawdust and offcuts, or building site contamination.
M J Kennedy, G Palmer

Effects of boron treatments on partially decayed oak and pitch pine heartwood
1996 - IRG/WP 96-30106
This paper reports results of borate based preservative treatment and leaching experiments on partially decayed oak and pitch pine heartwood. Previous experiments have shown little damage is caused to sound timber of these types when treated with Polybor and Boracol 20 preservatives. This experiment was carried out to assess the suitability of selected borate based preservatives for use in historical ships' timbers and therefore the physical effects of these preservatives on such timber was investigated. The results indicate that weight losses incurred due to treatment with Polybor or Boracol 20 are no more damaging than those incurred by treatment with water. Weight changes were more apparent in decayed timber than in sound timber with greater uptakes in non-leached samples and greater weight losses in leached samples. However, comparable weight changes were recorded between water treated samples and preservative treated samples. Dimensional changes were minimal in most cases, the greatest found in non-leached Boracol 20 samples as expected. These results indicate that treatment with these preservatives is suitable for partially decayed oak and pitch pine heartwood.
S McCutcheon, G M Smith, J W Palfreyman, P Durrant

The effect of ACC (Celcure) on durability of blue beech
1999 - IRG/WP 99-30209
Durability of the sapwood and heartwood of blue beech (Carpinus betulus) against white rot fungus (Coriolus versicolor) was studied. As treatment three concentrations of preservative (control or 0%, 3%, and 5% of ACC) were applied. The measuring 1.5x2.5x5cm3 as dimension of wood samples (sap and heartwood) was used. During 16 weeks exposure, untreated wood blocks were completely deteriorated by the fungus and their weight losses were 24.4% in sapwood and 23.4% in heartwood. However, 3% and 5% of ACC caused that weight losses were significantly decreased. In 3% of preservative sapwood decreased only 1.08%, and heartwood reduced 0.94%. In 5% of ACC weight losses were 0.97% (sapwood) and 1.03% (heartwood). Thus there was a significant difference between treated and untreated wood, and no significant differences were occurred between sapwood and heartwood when exposed to the white rot fungus.
S M Kazemi

Natural durability of Iranian saxual wood (Haloxylon persicum) against the fungal decay
1991 - IRG/WP 1515
Haloxylon persicum is vidly planted in the deserfic region of Iran. At the present time, in the age of 30, these small trees are ready for cutting for the different uses, specially for rural buildings. But there's any knowledge about its durability. In this study the laboratory tests were carried out in accordance to European Standard. 5 fungi were used as: Trametes versicolor, Coniophora puteana, Poria placenta, Gloeophyllum trabeum and Stereum hirsutum. The result show that the saxual wood can be classified as resistent. It has a service life of more than ten years exposed in a mediterranean climate. Therefore the use of round wood of converted wood for out side constructions such as f.ex. rural building can be recommended.
D Parsapajouh, F H Schweingruber, K Richter

Soft rot studies on CCA treated eucalypt power transmission poles
1981 - IRG/WP 1132
Initial results found for sixty CCA treated eucalypt poles, from a soft-rot survey are discussed. Retentions of CCA within above and below ground pole samples were variable. The variation was attributed mostly to biodegradation and effect of soil environment, rather than leaching. Bacterial decay was found in many poles and was severe in some cases. Although found in the presence of soft-rot decay, bacterial attack also dominated in regions of the CCA treated sapwood. Timber suffering such attack was appreciably softened. Extracellular layers have been observed around fungal hyphae from agar cultures and within soft-rot cavities. Fungal isolates were used to produce such polysaccharides. This material was used to observe the effect of addition of copper and quaternary ammonium compound. Solutions of extracellular polysaccharides exhibited some ability to bind copper and remove it from solution. In the presence of a quaternary compound polysaccharide was precipitated from solution.
L E Leightley

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