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Steam conditioning of partially dried radiata and Corsican pine roundwood
1988 - IRG/WP 3499
The effect of partial air drying prior to steam conditioning and its effect on subsequent preservative treatment by the Bethell treatment process was investigated. A high standard of preservative treatment was obtained in both radiata and Corsican pine, irrespective of whether a period of partial drying was imposed before or after steam conditioning.
P Vinden, D R Page, K Nasheri

The effect of treatment method on CCA efficacy in Corsican pine
1992 - IRG/WP 92-3723
As part of a study into the influence of application method on preservative efficacy Corsican pine (Pinus nigra) samples (50 x 50 x 400 mm³) were treated with a CCA formulation using Bethel, Steam/Bethel or Lowry processes. Full penetration of the preservative at a gross level was confirmed using a copper disclosing reagent. The preservative was allowed to fix and then samples were converted into mini-blocks (30 x 10 x 5 mm³) to produce decay test samples from various locations within the larger samples. After leaching, sets of replicate mini-blocks were exposed to the decay fungi Coniophora puteana FPRL 11E, Coriolus versicolor FPRL 28A, and Chaetomium globosum FPRL S70K. Equivalent sets of leached blocks, were analysed using atomic absorption spectrophotometry to determine preservative concentration and balance. The results of this study have been used to assess the effect of preservative application method on CCA efficacy. They also indicate how treatment method affects the distribution of the active elements of the preservative throughout the treated wood.
P R Newman, R J Murphy

Insect transmission of fungal sapstain to freshly sawn unseasoned softwood lumber
1994 - IRG/WP 94-20025
Chemical dip treatments were used to investigate micro-arthropod transmission of fungal sapstain to unseasoned pine sapwood boards. Saptain, mould and basidiomycete defacement of chemically treated sawn boards of Corsican pine was recorded during a 14 week field trial. Boards were treated with either a fungicide, an insecticide/acaricide, a combination of the fungicide with the insecticide/acaricide or with water which served as a control. Sapstain defacement of the control boards was severe after 8 and 14 weeks; mould defacement was slight. The fungicidal treatment prevented sapstain and mould development throughout the 14 week trial, both on its own and also when combined with the insecticide/acaricide. At 8 weeks the insecticidal/acaricidal treated boards were only slightly stained but showed a high degree of moulding. By 14 weeks the degree of staining of these boards had increased but was still significantly less than that recorded on the control boards whilst the recorded level of mould defacement was significantly reduced. The importance of insects as vectors of saptain fungi to sawn softwood lumber is discussed.
M A Powell, R A Eaton, J F Webber

Efficacy of linear chain carboxylic acid anhydrides as wood protection chemicals
2002 - IRG/WP 02-30295
This paper presents an assessment of the effectiveness of linear chain carboxylic acid anhydrides namely, acetic, propionic, butyric, valeric and hexanoic anhydride, in improving the decay resistance of Corsican pine (Pinus nigra Schneid) sapwood. Wood-anhydride bond formation was verified by the increase in sample weight and volume. A brown rot fungus [Coniophora puteana (Schum.:Fr)] was selected in order to determine and compare the effectiveness (threshold value) of linear chain anhydrides. The work described in this paper has demonstrated that chemically modified Corsican pine sapwood afforded substantial bioprotection against Coniophora puteana. It required a weight gain of approximately 16-18% following reaction to ensure complete protection. No strong and consistent trends could be identified to indicate the advantage of using one of the anhydrides in preference to another.
A N Papadopoulos, M D C Hale, C A S Hill

Treatment application method and CCA efficacy in Corsican pine - Assessment by serial exposure and soil burial tests
1993 - IRG/WP 93-40006
A previous report on this research (Newman and Murphy, 1992) identified possible variation in the efficacy of a CCA preservative applied to Corsican pine (Pinus nigra var. maritima) dependant upon the treatment application method (Bethel, Lowry or Steam/Bethel). This paper presents further data from biological testing of CCA treated Corsican pine using serial exposure and unsterile soil techniques. After 3 serial exposures to Coniophora puteana FPRL 11E and Coriolus versicolor FPRL 28A the treated wood performed in the order Bethel > Steam/Bethel > Lowry and Lowry > Bethel > Steam/Bethel respectively. Weight losses in the order of 40% and 30% were generated by Coniophora puteana and Coriolus versicolor at retentions of 3.9 kg/m³ and 1.0 kg/m³ CCA respectively. After 12 and 26 weeks unsterile soil burial the order was Lowry > Bethel > Steam/Bethel with weight losses of up to 30% at 1.0 kg/m³ CCA. The data are considered in relation to the decay mechanisms of the various biological agents used.
P R Newman, R J Murphy

Pretreatment decay in air-seasoning Scots and Corsican pine poles in England
1989 - IRG/WP 1390
British grown Scots and Corsican pine poles were sampled for colonization by basidiomycetes after air-seasoning for 6 to 9, or 16 to 20 months. The amount of infection present in these poles was compared with that in poles which were imported from Finland. After 6 to 9 months seasoning, the British grown pine poles were heavily infected with Peniophora gigantea, Cylindrobasidium evolvens, Stereum sanguinolentum, and Heterobasidion annosum, which were isolated from about 35, 20, 10, and 6% of the increment cores sampled, respectively. In poles which had seasoned for 16 to 20 months, the frequency of isolation of Stereum sanguinolentum was much greater, while that of Cylindrobasidium evolvens had decreased. Poles imported from Finland were heavily colonized by Stereum sanguinolentum and Cylindrobasidium evolvens (40 and 35% of cores, respectively), but generally showed little colonization by Peniophora gigantea and none by Heterobasidion annosum. The high incidence of Peniophora gigantea in British grown poles from forests where this fungus is used as a stump treatment to control Heterobasidion annosum may be cause for concern.
A R Zahora, D J Dickinson

Defacement of freshly sawn Corsican pine lumber by sapstain and mould fungi and the influence of arthropods
1997 - IRG/WP 97-10227
In a trial to study the arthropods associated with sapstain and mould fungi, freshly sawn Corsican pine (Pinus nigra var. maritima (Aiton) Melville) boards were block stacked at a local sawmill. Each stack was constructed in a nest arrangement with smaller boards in experimental tanks, positioned in the centre of the stacks. Boards were converted from a stock of sawlogs at monthly intervals, to provide host material of different ages. Filters and screens were used to exclude arthropods and airborne inoculum from selected experimental tanks. The experimental tanks were removed monthly and the insect community and fungal defacement assessed. The highest numbers of arthropods were recorded during the summer months, maximum numbers being approximately 20 insects and 100 mites per 500 cm2 board surface. Ninety-four species of arthropods have been identified from the experimental material (sawlogs through to experimental boards) with 90% from within the stacked lumber itself. The most abundant were Dipteran larvae, fungus gnats (Mycetophilidae: Diptera) and Atheta coriaria Kraatz (Staphylinidae: Coleoptera). The exclusion of the arthropods from experimental tanks lead to a significant rise in the amount of mould, but not sapstain fungi. Studies were carried out at different seasons over two years. The significance of arthropods in the fungal defacement of sawn lumber is discussed.
N J Strong, J F Webber, R A Eaton

The control and pretreatment decay in air seasoning Scots and Corsican pine poles in England
1990 - IRG/WP 1451
Previous work clearly showed that air-seasoned, British grown Scots and Corsican pine poles are subject to serious pretreatment decay. In order to control these infections a range of pretreatments are currently being investigated. One series of treatments is designed not only to control decay but also allow the development of mould and stain fungi in order to achieve the desired increases in porosity prior to creosoting. The trial is due to run for a total of 18 months. The initial results have been very encouraging and due to the considerable current interest in this area the results for 6 and 12 month samplings are presented in this short preliminary report to the sub-group. Simple borate treatments have effectively prevented the development of basidiomycetes but allowed mould and stain development. This has led to the subsequent, desired porosity increases and initial creosote treatments appear very good.
D J Dickinson, A R Zahora, A P Dodson

Partial seasoning and preservative treatment systems for pine roundwood
1982 - IRG/WP 3187
Experimental trials at FRI, Rotorua showed that the steaming schedule normally used for steaming and venting is also suitable for steaming and vacuum seasoning. Applying vacuum of up to -84 kPa immediately after steaming did not increase the initial loss of wood moisture significantly in comparison to steam/venting. The main improvement to wood condition by using steam/vacuum appeared to be to distribution of moisture within, and possibly between, posts. Bethell treatment of Corsican pine posts one day after steam/vacuum was not of a satisfactory standard. However, the steam/vacuum/Bethell system may offer a worthwhile reduction in the holding period specified for the steam/vent/Bethell ('Q') system. A shortened and simplified Alternating Pressure Method (APM) process was used to treat Corsican pine posts one day after steam/vacuum. The standard of treatment obtained by using this system was evaluated at FRI and at a commercial treatment plant and showed potential to treat wood to low retention variability. As a result of these trials the New Zealand Timber Preservation Authority has approved a steam/vacuum/APM schedule for the treatment of radiata and Corsican pine rounds up to 250 mm large end diameter.
A J Bergervoet

Confocal laser scanning microscopy of a novel decay in preservative treated radiata pine in wet acidic soils
1997 - IRG/WP 97-10215
Light microscopy of radiata pine (Pinus radiata D. Don) field test stakes (20x20x500mm3) exposed in wet acidic (pH 3-4) soil for 12 - 24 months showed predominance of an unusual type of decay characte-rised by tunnelling attack of wood cell walls. After two years decay was moderate to severe in wood treated to ground contact CCA specifications and also equivalent retentions of creosote, and a number of new generation preservatives. Relative to other New Zealand temperate test sites and also an Australian tropical site, the New Zealand acidic soil test site was very aggressive. Correlative scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to elucidate the micromorphology of this attack. Tunnels of diameter 0.2-5 µm were present throughout all layers of the cell wall, and their orientation was not related to cellulose microfibril orientation. They also showed no preference for particular cell wall layers, indicating a lignin degrading capability. CLSM images showed that living, connecting fungal hyphae were present in the cell lumina and tunnels. This type of attack was predominant in wood that was highly saturated with water whereas wood that was less moist was predominantly attacked by classical white rot. Ongoing isolation and incubation studies in conjunction with further microscopy should enable identification of the fungal species involved.
R N Wakeling, Ying Xiao, A P Singh

Field trial with poles of Scots pine treated with six different creosotes
1996 - IRG/WP 96-30115
In the middle of the 50's field trials with creosote-treated poles were started in France, Germany and Sweden. The trials were initiated by WEI (Western-European Institute for Wood Preservation). Six different creosotes were used and 40 poles per creosote were installed at each test field. Results after 39 years of exposure in Simlangsdalen, Sweden are reported. Poles treated with a heavy creosote were less decayed than poles treated with medium-heavy creosotes. Poles treated with a light creosote were most decayed.
Ö Bergman

Screening potential preservatives against stain and mould fungi on pine timber in Zimbabwe
1995 - IRG/WP 95-30063
The search for environmentally and toxicologically safer chemicals for use in the timber preservative industry against stain and mould fungi has been intensified during the past few years. Results of field tests with two chemicals previously evaluated in the laboratory are presented. The conventional sodium pentachlorophenate was the more efficacious chemical against stain and mould fungi, providing up 90% control at a concentration of 2.5%. A potential alternative, Stopstain a borate-based chemical, gave results only slightly better than the untreated control timber, at a concentration of 5%. Unless the environmental cost and toxicological hazards of traditional chemicals are highlighted the newer and safer chemicals will be reluctantly accepted by industry as they are regarded as being prohibitively expensive.
A J Masuka

Dimensional stability and decay resistance of hot-melt self-bonded particleboard by surface benzylated pine chips
1991 - IRG/WP 3652
Akamatsu (Pinus densiflora Sieb. et Zucc: Japanese red pine) particles were pretreated with 40% NaOH solution and benzylated with benzyl chloride, and the surface of particle was converted into meltable materials. Hot-melt self bonded particleboard having smooth and high glossiness surface was prepared by hot pressing at 150°C and 1.96 MPa without using any conventional adhesives. Dimensional stability and decay resistance of the benzylated particleboard were evaluated. Particleboards made of benzylated particles having more than 38% of weight percent gain (WPG) showed that dimensional stability and decay resistance were superior to the conventional particleboard made by using phenolformaldehyde resin as a binder, because hydroxyl groups of wood were substituted by hydrophobic benzyl groups with benzylation. Though bending strength of the board was a little lower than control board due to the damage of benzylated particles during benzylation, its internal bonding strength was very high, because the hot-melting strengthened the inter-particle bonding.
M Kiguchi, K Yamamoto

Strength loss associated with steam conditioning and boron treatment of radiata pine framing
1987 - IRG/WP 3438
The combined effect of included defects and wood moisture content on the strength loss of second rotation radiata pine framing following conventional steam conditioning is investigated. The green Modulus of Elasticity (MOE) is reduced by approximately 13% after steaming. When dried after steaming, however, neither the MOE nor MOR is significantly different from unsteamed dried controls.
M J Collins, P Vinden

Soil virulence tests using Scots pine sapwood
1973 - IRG/WP 222
Following the tests reported in Document No: IRG/WP/210, in which soils from different laboratories were investigated for virulence, supplementary tests have been carried out using Scots pine sapwood and an extended incubation period.
J K Carey, J G Savory

Types of decay observed in CCA-treated pine posts in horticultural situations in New Zealand
1984 - IRG/WP 1226
The few reported failures of 11-12-year-old horticultural posts in New Zealand in 1982 were caused by brown-rot. A subsequent survey of CCA-treated posts in all the major horticultural areas has revealed decay of many posts. A microscopic examination of these posts has shown decay by brown-rot, white-rot, soft-rot and bacteria. Several types of bacterial decay have been observed.
J A Drysdale, M E Hedley

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

Termite resistance of pine wood treated with chromated copper arsenates
1997 - IRG/WP 97-30128
Two four-week, no-choice laboratory tests were performed with CCA-treated southern yellow pine and radiata pine against Formosan subterranean termites, Coptotermes formosanus. CCA retentions as low as 0.05 kg/m3 (0.03 pcf) provided protection from all but light termite attack (rating of 9 on a 10-point visual scale). Similar and consistent light attack on wafers containing retentions as high as 6.4 kg/m3 (0.4 pcf), coupled with complete termite mortality, demonstrates that the mode of action of CCA treatments relies upon toxicity rather than having any repellent effects against termites.
J K Grace

Durability of pine modified by 9 different methods
2004 - IRG/WP 04-40288
The decay resistance was studied for pine modified by nine methods of wood modification: 1) Acetylation, 2) Treatment with methylated melamine resin (MMF), 3) Acetylation followed by post-treatment with MMF-resin, 4) Thermal modification, 5) Furfurylation, 6) Maleoylation (using water solution of MG or ethanol solution of maleic anhydride), 7) Succinylation, 8) NMA-modification and 9) modification with reactive linseed oil derivative (UZA), Wood blocks of Scots pine (Pinus sylvestris L.) sapwood were modified in pilot plants. Methods 1-5 were performed by the authors at Chalmers University of Technology or at BFH in Hamburg. Methods 5-9 were part of a European research project (the Chemowood project, FAIR-CT97-3187) and therefore each of these modifications was performed by the project participant responsible for the method. For laboratory testing in TMCs (modified European standard ENV 807) and pure basidiomycete culture bioassays, smaller test specimens were cut from the modified wood blocks. Most of the modification methods were applied on test specimens for marine field testing (EN 275) and some methods to produce mini-stakes for field tests in five Swedish fields. Some modification methods result in modified wood with poor durability, whereas other methods (acetylation, furfurylation and MMF-treatment) seem to provide excellent resistance to microbial decay.
M Westin, A O Rapp, T Nilsson

Performance of Tebbacop in laboratory, fungus cellar and field tests
2000 - IRG/WP 00-30222
A novel organo-copper wood preservative ("Tebbacop") has been exposed to 12 years fungus cellar testing and 6 years above ground field testing. In the fungus cellar, Tebbacop at a retention of 0.053% Cu m/m oven dry wood out-performed CCA at a retention of 0.55% m/m oven dry wood. In above ground tests, L-joints treated to a Tebbacop retention of 0.012% Cu are performing as well as joints treated with TBTN to a retention of 0.08% Sn. In a slightly more severe decking test, 0.016% Cu as Tebbacop was more effective than 0.08% Sn as TBTN.
M E Hedley, D R Page, B E Patterson

Leaching of copper, chromium and arsenic from CCA-treated Scots pine exposed in sea water
2000 - IRG/WP 00-50149
A laboratory leaching trial combining a static and a flowing seawater system was carried out to measure the leaching rates of copper, chromium and arsenic from the surface of Scots pine panels vacuum-pressure treated to 3, 6, 12, 24, and 48 kgm-3 CCA. Untreated and treated panels were exposed in flowing seawater for up to 8 weeks followed by 2 weeks submersion in static seawater which was taken for analysis. The study revealed a leaching hierarchy of Cu>Cr>As which supports the findings of other investigators. Over the 8 week leaching trial there was a time-related decrease in the rate of copper and chromium loss. Over the first week of leaching in flowing seawater, the rates of loss of copper and chromium decreased to between one-half and one-seventh, followed by lower rates of leaching over the remaining period of the investigation. In contrast, the rate of loss of arsenic from the wood appeared to increase slightly over the same period. The data are compared with minimal leaching rates of toxins from the surface of anti-fouling paints and are discussed in terms of the fouling communities which are established on Scots pine panels treated to similar target retentions.
C J Brown, R A Eaton

Creosoted radiata pine by non-pressure methods
1988 - IRG/WP 3486
Posts of Pinus radiata have been impregnated with creosote by immersion for 1, 3, and 7 days, and by hot-and-cold open tank with hot bath temperatures at 40°C and 60°C. On the basis of the retention rates obtained, suitable procedures are described for wood elements that are going to be in ground contact, and an analysis is made of the way in which the variables tested affect the results.
M V Baonza Merino, C De Arana Moncada

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.
P Vinden

Dimensional stabilization of wood with dimethylol compounds
1987 - IRG/WP 3412
This study showed that a substantial degree of dimensional stability can be imparted to wood by crosslinking with low concentrations of dimethyloldihydroxyethyleneurea. It was demonstrated that by selecting the right catalyst system the cure temperature can be reduced to the point that strength loss of the treated wood is minimized.
D D Nicholas, A D Williams

Movement of boron from fused boron rods implanted in Southern pine, Douglas fir, red oak, and white oak timbers
1995 - IRG/WP 95-30061
This paper reports the distribution of boron from fused boron rods installed into six-inch (15.2 cm) square timbers of Douglas-fir, Southern Pine, red oak and white oak exposed aboveground. The composition and size of rods was: sodium borate and sodium borate-copper oxide (8.5 x 100 mm²); sodium borate-copper, sodium borate and boric oxide-copper oxide (12 x 76 mm²). The boric acid equivalent was roughly monitored by the curcumin/salicylic acid color test and the presence of copper was detected by the chrome azurol-S reagent. One year after installation of rods, movement of boron was determined by application of curcumin dye to increment cores removed at various distances from the site of boron rod installation. A portion of a sodium borate treated Southern Pine timber was also analyzed by spraying curcumin dye on sawed longitudinal and transverse sections. At 2 years, one foot sections were removed from all timber species, sawed as above, and boron and copper detection reagent sprayed on the sawed surfaces. Movement of copper from rods in all timbers was virtually nil. Both transverse and longitudinal movement of boron from rods was greatest in Southern pine which also had the highest moisture content. Movement of boron was next best in red oak. There was little movement of boron away from the rods in white oak and Douglas-fir.
T L Highley, L Ferge

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