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Adequate preservative treatment of kiln dried Eucalyptus camaldulensis and Acacia mangium for tropical and subtropical wood poles
1996 - IRG/WP 96-40075
The Eucalyptus camaldulensis and Acacia mangium round timbers kiln-dried at EMC and full cell pressure treated with CCA-C ensured requisite penetration and adequate dry retention (30 kg/m³ or 4% w/w). The sufficient inherent strength, seasoning property, treatability of sapwood and heartwood equivalent to 44% of radius, natural durability of heartwood, and field investigation on service performance of similar hardwood poles treated with CCA-C, pentachlorophenol and creosote ensured their longterm use as tropical and subtropical poles.
A K Lahiry


Laboratory Leaching Tests to Study the Effects of Post-Treatment Storage Periods on CCA Leachability and Fixation in Treated Permeable and Refractory Malaysian Hardwoods
2006 - IRG/WP 06-50240
The biological resistance and environmental safety of CCA-treated wood relies on the extent of post-treatment storage fixation of CCA in wood prior to being utilized. A study on the comparative leachability (fixation) of CCA-treated refractory and permeable heartwoods of 3 Malaysian hardwoods subjected to different post-treatment storage (fixation) periods of up to 4 weeks, at 2 laboratory leaching tests of the general procedure of EN84 was conducted. End-sealed test wood blocks of Malaysian species [permeable Menggris (Koompassia malaccensis) and Perah (Elateriospermum tapos), refractory Acacia mangium] were treated with CCA to target retention of 5.6 kg/m3, immediately stored to fix at ambient conditions for 0 and 48 hours, 1, 2 and 4 weeks, followed by a 2 weeks leaching test to determine cumulative leaching losses of copper (Cu), chromium (Cr) and arsenic (As). Generally, levels of leached CCA components were: 4.0 – 47.4 µg/cm2 Cu, 9.1 – 127.0 µg/cm2 Cr, and 5.2 – 56.9 µg/cm2 As. For all leachate elements, there were less distinct variations in leaching losses (P<0.05) between 4 storage (fixation) periods, more significant variation between unfixed and stored fixed blocks and between refractory and permeable wood species. Component leaching losses were greater in refractory than permeable heartwoods of timbers, while increasing with reduced storage periods overall. No significant differences in CCA leaching losses were found between EN84 method (consisting of initial vacuum impregnation of wood in water) and the variant of the EN84 method (initial immersion of wood in water), implying that the former method could not result in higher CCA leaching losses than the latter method.
A H H Wong, H C Lai, N P T Lim


Needs for wood durability research on planted tree species in the tropics
2008 - IRG/WP 08-10651
The area of forest plantation has been expanding especially in tropical Asia since 1990’s. Most of them are developed for pulp and paper industries and planted with fast growing trees. It is expected that wood from those fast growing trees are also used for value added products such as sawn timber. In order to promote the utilization of fast wood as the resource of value added products, natural durability was examined by an accelerated decay test according to JIS Z2101 in Acacia species, Melaleuca species, and Tectona grandis from the sapwood to the heartwood. Weight losses of the examined heartwood indicated that A. auriculiformis, hybrid Acacia and T, grandis were classified into moderately durable, A. mangium was slightly durable, and both of Melaleuca species were non-durable. There were no difference found between planted and natural grown teak (T. grandis). All of sapwood examined was not durable. The proportion of heartwood in the stem is considered to be an important factor in plantation trees when these trees are used for value added products.
K Yamamoto, T Toma, Ngo Duc Hiep, Nguyen Trong Nhan


IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water. Progress Report 2: Report of treatment and installation in Australia
1978 - IRG/WP 440
The purpose of this test and the procedures to be followed have been fully set out in documents distributed by the International Research Group on Wood Preservation and numbered IRG/WP/414 and IRG/WP/420. The prescriptions set out in these two documents have been closely followed.
J Beesley


The 1999-2000 annual report for the IRG - Wood Preservation in Egypt
2000 - IRG/WP 00-40188
The wood destroying insects in Egypt are belonging to several families of Coleoptera, Lepidoptera and Isoptera. Imported woods are treated by The Agricultural Quarantine or the authorized companies. The materials used for protection as pre-treatment are the same of the treatment. They are Bromide methyl, copper or fluoride salts, organo-phosphorus compounds, pyrethroides, creosote or creosodial. Any preservative should be evaluated by the Ministry of Agriculture before recommendation. Of the preserved woods are Lumbers, sleepers and poles, woods used in constructions and furniture as well. The woods used in furniture, constructions or woodworks are mostly imported from Sweden, Russia, Finland or Korea. Several kinds of woods are imported as Picea sp., Pinus sp., Phagus sp. Local woods used are limited in kinds and amount, as Casuarina sp., Eucalyptus sp., Ficus sp., Acacia sp. Treated woods are potentially increasing in use. There are neither restriction for the use of treated woods, not any regulation concerning the desposal of these woods.
S I M Moein


Wood preservation in Kenya
2000 - IRG/WP 00-40190
Focussing an Wood Preservation in Kenya, the Report discusses and elaborates on Education and Training, Research, Wood deteriorating organisms, Treatment Plants and Processes, Preserving Chemicals, Specifications, Markets, Health and Safety and Environmental issues. Education and Research is limited to one Institution only, other Institutions involved with the properties and utilization of wood hardly touches Preservation. Publications and results of Research Projects over the years have emanated from that Institution. Conferences have not been held for a long time in the country. Fungi, insects, including termites, and Marine borers, are all present in the country. The amount of untreated or poorly treated wood lost through the activities of these organisms is substantial. Treatment is usually of a general nature, assuming that Schedules used will protect timber against all agents of decay. The Kenyan Wood Preservation Industry, now 50 years old and with some 27 Plants around the country, has not explored other Wood Preserving Chemicals or Treatment methods. The four Preservatives used are still CCA, Creosote, BFCA and PCP. The Bethel Process is used by all pressure Plants (CCA and Creosote), with only one immersion Plant (BFCA and PCP). Eucalyptus, Acacia,Cypress and some are the species commonly treated, mainly for the local market with some exports. Schedules have not been properly worked out for different end uses. Transmission, Telegraph poles and Fencing posts comprise the bulk of timber treated, with smaller amounts of Construction timber and Horticultural poles. The four Chemicals used are of foreign origin, imported by Treatment Plants. Apart from a few Standards formulated by the Kenya Bureau of Standards (KBS), there are no other Standards or Codes of Practice to guide the Industry and Users of treated timbers. Specifications have not been fully worked out. The KBS is the only Authority responsible for Quality Control and Certification. Health and Safety of Plant operatives is not of major concern. Problems associated with Toxic Preserving Chemicals in the environment has not been fully addressed yet.
R Venkatasamy


Boron treatment methods for lyctid susceptible hardwoods growing in Tasmania
1998 - IRG/WP 98-30168
A survey of existing boron plants that treat to protect hardwoods from attack by lyctids in Australia showed that hot and cold bath, and vacuum pressure impregnation (vpi), were the two most common methods employed. In experimental work, two of the treatment methods, vpi and dip diffusion, were used to treat seasoned and green messmate (Eucalyptus obliqua) and blackwood (Acacia melanoxylon). The treating solution in both cases was Diffusol. For vpi treatment, a solution of 2.5% boric acid equivalent (BAE) was used to treat rough sawn boards with a Bethell schedule. After treatment, boards were strip stacked on a pallet under cover, later cut in half, and the centres sprayed with turmeric reagent to reveal that all sapwood was adequately treated with boron. The solution for dip diffusion contained 12% BAE. Block stacked timber was dipped, wrapped, and stored to allow diffusion of the boron. All green E. obliqua and A. melanoxylon boards were adequately treated after dipping in Diffusol and two, four or six weeks diffusion. Some of the air dried A. melanoxylon boards could not be adequately treated by this method when diffusion periods were just two or four weeks. However, a six week diffusion period allowed full sapwood treatment of all boards.
L J Cookson, D Scown, K McCarthy


An aquaria test of the natural resistance against marine borers of some commercial timbers available in Australia
1996 - IRG/WP 96-10145
The natural resistance of the heartwood of 22 different timbers grown or commercially available in Australia was examined. Radiata pine sapwood both untreated, and treated with 5.4 kg/m³ CCA salt, was included for comparison. Small timber blocks were exposed for one year in tanks containing either Limnoria tripunctata or Lyrodus pedicellatus. Four softwood species tested were heavily attacked and non resistant: radiata pine sapwood, Douglas fir, Huon pine and King William Pine. The latter two species are moderately durable in ground contact. Both white and black cypress pine were lightly attacked. Most hardwoods examined that are durable on land, also performed well in the aquaria, although none were immune from marine borer attack. Blocks in aquaria with Lyrodus pedicellatus were generally more decayed by marine microorganisms than blocks placed with Limnoria tripunctata. Limnoria is able to leave its burrow, and probably grazes on surface mycelia.
L J Cookson


Preservative technique of three commercially important timber species – Sissoo (Dalbergia sissoo), Akasmoni (Acacia auriculiformis) and Ghoraneem (Melia azedarach) of Bangladesh
2005 - IRG/WP 05-40299
Wood is renewable resource and is widely used as construction material in rural and urban areas of Bangladesh. Dalbergia sissoo, Acacia auriculiformis and Melia azedarach, locally known as Sissoo, Akasmoni and Ghoraneem respectively are three important timber species of Bangladesh. These are used for different purposes normally without preservative treatment. Heartwood of Sissoo, Akasmoni and Ghoraneem are naturally durable but sapwood is not durable. But the presence of sapwood in Sissoo, Akasmoni and Ghoraneem are approximately 43 %, 49 % and 55 % respectively. Discut the use of sapwood of Sissoo, Akasmoni and Ghoraneem might increase the price of wood very high. So it need preservative treatment to increase its durability. Preservative treatment protects them from various biodegradable agents such as fungi and insects. So the study of preservative treatment of the three wood species was undertaken using chromate, copper boron (CCB) preservative by dipping method. Three important physical properties of wood viz moisture content, density and shrinkage of the species were also studied. Akashmoni showed higher moisture content but lower density than Sissoo. Again Sissoo showed higher density and Akashmoni showed higher shrinkage than the two other wood species. Preservative treatment was carried out with four different preservative concentrations of 4, 5, 6 and 7 % and dipping schedule of 4, 6, 8 and 10 days. It was observed that penetration and retention of CCB was always higher in Sissoo than the two other species which is a clear indication to consider.
M R Bulbul, M O Hannan, P K Sarker, A A Mahafuz, G N M Ilias


Protection and efficient utilization of plantation grown lesser-known timbers of arid region in India - Acacia tortilis, Prosopis juliflora and Prosopis cineraria
2005 - IRG/WP 05-40321
The plantation-grown timbers are highly susceptible to insects/pests, borers and wood rot fungus. Wood preservatives copper chrome arsenic (CCA) 2% and chloropyriphos 2% solution treated under pressure on three plantation grown timber species viz. Acacia tortilis, Prosopis juliflora and Prosopis cineraria have shown encouraging results in enhancement of shelf life by protection of wood against wood rot fungus, pests and insects. These species are grown in arid/semi arid region for sand dune stabilization/ pastureland development. Timber from these species particularly A. tortilis and P. cineraria are prone to pests and insect attack immediately after felling, for this reason wood is used only as firewood. Furniture and handicraft items made from treated and seasoned wood are exhibiting very good appearance and unaffected by deteriorating agents. Value addition of these timbers by preservative treatment and seasoning can boost the better utilization of wood for products like low cost furniture’s, curios and other handicraft items. The demand for wooden handicraft is increasing every day, application of this technique on utilization of plantation grown timbers can reduce pressure to some extent on supply of traditionally used timber species like Teak and Shisham, thus the conservation of natural resource.
S H Jain, H Kumar, R Arya, R L Srivastava


Differential retention and leaching of CCA (C) in sapwood and heartwood of Kenyan-grown blue gum (Eucalyptus saligna) and black wattle (Acacia mearnsii)
2005 - IRG/WP 05-30371
Retention and leaching of CCA(C) in small samples of sapwood and heartwood of Kenyan-grown blue gum (Eucalyptus saligna) and black wattle (Acacia mearnsii) were tested under laboratory conditions. Clear samples (100mm x 30mm x 40mm) were removed from the sapwood and heartwood of sampled defect-free and sound plantation trees of the two species. These were separately air-dried to 15% MC, end-sealed and pressure-treated with 3% CCA-C (oxide) at a commercial treatment plant. They were then conditioned at ambient temperature, air-dried to 15% MC and retentions calculated on a weight-gain basis (E. saligna: sapwood - 33.3 Kg/M3, heartwood - 6.4 Kg/M3; A. mearnsii: sapwood - 28.7 Kg/M3, heartwood - 5.6 Kg/M3). Batches of samples of sapwood and heartwood of each species were then separately leached in running tap water for 3, 6, 9, 12, 15, 18 and 21 days. After each leaching period, batches of samples were removed, oven-dried to 15% MC, and the amount of preservative leached calculated on a weight-loss basis. After 21 days of leaching, substantial amounts of the preservative were removed from sapwood samples (E. saligna - 44.1%; A. mearnsii - 47.7%), whereas losses of the preservative from heartwood samples were significantly lower, 18.7% and 16.1% for E. saligna and A. mearnsii respectively. The results indicate that although retentions may be higher in sapwood than in heartwood of these two species, fixation of CCA appears to be poorer in sapwood, resulting in higher losses of the preservative through leaching. Mechanisms responsible for differential retention, fixation, and leaching of CCA in sapwood and heartwood on these two species need to be further studied and documented.
R Venkatasamy


The effects of pH on leaching of copper-chrome-arsenate (CCA) from pressure-treated Kenyan-grown Eucalyptus saligna and Acacia mearnsii: Initial findings.
2002 - IRG/WP 02-30298
The effects of pH on leaching of CCA from pressure-treated Kenyan-grown Eucalyptus saligna and Acacia mearnsii were tested under laboratory conditions. Small samples of the two species (100mm x 30mm x 40mm) were smooth sawn from 8-year old trees to represent equal amounts of both sapwood and heartwood, air-dried to 12% moisture content, end-sealed, and pressure-treated at a commercial treatment plant (6% CCA-C oxide type). They were then conditioned and air-dried to 12% moisture content and average retentions for each species calculated, (18.2Kg/M3 for eucalyptus and 17.3Kg/M3 for acacia). Batches of samples of each species were then separately leached for 3, 6, 9, 12, 15, 18, and 21 days in tap water, with the pH adjusted to 3.0, 6.0, and 8.0. After each leaching regime samples were removed, oven-dried to 12% moisture content, and the amount of CCA leached out calculated on a weight loss basis. The results revealed that, after 21 days, leaching of CCA from the two species was highest at pH 3.0 (9.8Kg/M3 or 53.8% for E. saligna; 10.2Kg/M3 or 58.4% for A. mearnsii). Lower amounts of CCA were leached at pH 8.0 after 21 days, 5.5Kg/M3 or 30.2% for E. saligna and 6.0Kg/M3 or 34.1% for A. mearnsii. Leaching after 21 days was lowest at pH 6.0, 4.4Kg/M3 or 24.2% for E.saligna, and 3.0Kg/M3 or 17.3% for A. mearnsii. For each of the pH level tested, both species appeared to lose more CCA during the firsts 12 days of leaching, amounts being then lower up to 21 days. The results indicated that CCA-treated poles and posts of E. saligna and A. mearnsii are likely to suffer from excessive preservative depletion, especially when used in acidic soils, leading to short service lives. Further investigations are necessary to establish whether depletion of CCA from these two species may be due to high lignin and tannin contents, or inappropriate treatment techniques.
R Venkatasamy


Influence of Grain Direction on Penetration, Retention, and Leaching of CCA(C) in Sapwood and Heartwood of Kenyan-Grown Eucalyptus saligna and Acacia mearnsii
2007 - IRG/WP 07-40383
Penetration, retention, and leaching of CCA (C) in relation to grain orientation were tested in small (50mm x 50mm x 200mm) sapwood and heartwood samples of Eucalyptus saligna and Acacia mearnsii. In both sapwood and heartwood of the two species, the results showed a consistent pattern: Transverse > Radial > Tangential. Whereas penetration, retention, and leaching were significantly high in the transverse grain direction for both species, magnitudes recorded for radial and tangential grain orientations were low. However, radial conductivity appeared to be consistently better that tangential conductivity of the preservative. Compared to the results for sapwood, penetration, retention, and leaching were significantly lower in heartwood samples of both species. It was noted that in heartwood samples of both species, percent leaching of the preservative was higher than in sapwood samples, irrespective of grain orientation. That was attributed to the high lignin contents in heartwood of E. saligna and A. mearnsii interfering with the fixation of CCA elements. High penetration of the preservative in the transverse grain direction is because of higher conductivity through large interconnecting vessels in the two species. Radial and tangential conduction relied on low volumes of parenchyma cells (rays) and small vessel and fibre pits. Low fluid conductivity in heartwood is mainly due to anatomical, physical and chemical changes that accompany transformation of sapwood to heartwood, hence low void spaces for preservative penetration. From the results, it becomes apparent that different treatment schedules must be worked out for effective treatment of posts and poles of E. saligna and A. mearnsii (where only an outer sapwood envelope treatment is required), and for sawn material with transverse, radial, and tangential faces exposed, in which case treatment would have to be evenly balanced.
R Venkatasamy


Durability of timber from exotic species against termite attack in Indian conditions
2007 - IRG/WP 07-10629
Exotic trees species, Acacia mangium Willd. and A. auriculiformis A. Cunn. ex Benth. and their hybrid are widely grown in India for multiple uses including use as timber. It is essential to know the natural durability of timbers against termites for predicting the service life of the timber and deciding on the application of preservatives to enhance the durability. Studies were conducted to test their durability against termites with and without chemical treatments and in comparison to the natural durability of Rubberwood, which is a highly perishable wood. Test panels (30.5 x 3.8 x 3.8 cm) were prepared from pure heartwood and treated with CCA (Copper-Chrome-Arsenic), Permethrin and Cashew Nut Shell liquid (CSNL) formulation by pressure impregnation. They were buried half their length in the termite test yard along with untreated stakes and rubber wood stakes and tested as per Indian standards (IS 4833-1968). Bimonthly observations on termite infestation were recorded for a period of 5 years. A. auriculiformis, A. mangium and the hybrid were found to be more durable as compared to Rubberwood, which was fully damaged within 6 months of field exposure. The hybrid was highly resistant to termite attack and both treated and untreated stakes were found undamaged or with negligible damage upto 5 years. A. auriculiformis was slightly less durable than hybrid showing 10% damage by 5 years. The damage in A. mangium was 10% by one year, more than 30% by 2 years and by 5 years the damage was 100%. Pressure treatment with CCA (4%) and Permethrin (1%) gave 100% protection to all stakes against termite attack in the field. CNSL (30%) treatment was also effective to a great extent. The comparative performance of different timbers on field exposure to subterranean termites is discussed in the paper.
O K Remadevi, R Muthukrishnan


An overview of recent studies involving the thermal modification of hardwood species
2019 - IRG/WP 19-40869
This paper outlines recent activities related to the thermal modification of hardwood species, and particularly to tropical hardwood species. Timber demand is ever increasing, but this is being limited by the necessity to protect virgin forest stands. As such, the majority of supply of popular species is being met from juvenile short rotation stands. The limited age from these stands often plays a significant role in the natural durability of the supplied material. This can lead to premature failure in service. Herein are described several series of experiments that consider the thermal modification of a range of species, such as oak, teak, meranti and acacia. The thermal modification, based on the ThermoWood® principle, was carried out at temperatures 160 °C, 180 °C and 210 °C. Results within relate to the chemical composition of the species and noted colour variations as a result of treatment. Additional work outlines ongoing studies into improving the fire resistance of selected species through the use of fire retardants (both synthetic and naturally occurring).
D Jones, M Gaff, F Kacik