IRG Documents Database and Compendium


Search and Download IRG Documents:



Between and , sort by


Displaying your search results

Your search resulted in 21 documents.


The biostatic effect of copper on decay of fire retardant-treated mining timber
1991 - IRG/WP 1507
Blocks of Eucalyptus grandis were treated with 20kg/m³ ammonium sulphate as fire retardant and challenged with Coriolus versicolor. Replicates were soil buried. A second set of blocks was treated with retardant and copper at 6.6 kg/m³ (ie 1% w/w), and challenged similarly. After 8 weeks weight losses produced by Coriolus versicolor in untreated, retardant treated and copper supplemented blocks were 45, 25, and 0% respectively, and corresponding weight losses in soil were 27, 25 and 10%. These results, and electronmicroscopical observations, showed conclusively that Eucalyptus grandis treated with fire retardant was rapidly decayed, and that copper inhibited such decay.
G D Shelver, E A Shelver, A A W Baecker


A new ground-contact wide-spectrum organic wood preservative: DNBP
1986 - IRG/WP 3358
A new organic wood preservative, which 25 years field tests have proved to be of efficiency and effectiveness comparable to CCA wood preservatives for ground-contact applications, is presented. Physical and chemical tests, supporting the long term field test results as well as indicating the characteristics of this preservative, are also presented.
W E Conradie, A Pizzi


Biological effectiveness of ground-contact wood preservatives as determined by field exposure stake tests
1984 - IRG/WP 3297
Field exposure tests conducted on stakes treated with different creosotes, mixtures of creosote and waxy oil as well as different CCA wood preservatives over a period of 25 years, gave the following results: The CCA preservatives provided excellent biological protection to treated stakes, especially against fungal attack. The CCA Type I, currently approved for use under South African conditions is not inferior to the CCA Type II during long-term ground-contact exposure if the active elemental contents and effective retentions are taken into consideration. The creosotes provided good protection against termite attack but showed fairly poor fungal resistance during long-term ground-contact exposure under wet conditions. The addition of waxy oil greatly improved the effectiveness of creosotes against fungal attack. The CCA preservatives proved to be a better overall ground-contact preservative compared with the creosotes.
W E Conradie, A Pizzi


Natural resistance of twenty-six Guianese wood species against marine borers
1988 - IRG/WP 4144
This note is a contribution on the study of the natural resistance of some wood species from French Guiana, some of which could be found too in the neighbourhood. Here are presented the results after one year exposure in the marine environment.
L N Trong


Natural durability of eight tropical hardwoods species from Africa
2005 - IRG/WP 05-10563
Current forest inventory results reveal that there are more than 700 hundred-hardwood species in tropical forests, of which less than 10 percent are harvested and used for commercial purposes. The increased use of lesser-known species can decrease the pressure on current commercial species, increase the value of the forest and lead to better management practices. However basic information on physical, mechanical, treatability, and durability properties of these lesser-known species are necessary before they can be advertised as suitable replacements for current species. This project investigates the natural durability to brown rot and white rot fungi of eight tropical commercial and secondary hardwood species: Ayous (Triplochiton scleroxylon), Acajou (Khaya ivorensis), Frake (Terminalia superba), African padauk (Pterocapus soyauxii), Amouk (Microberllinia brazzavilensis), Ilomba (Pycnanthus angolensis), Iroko (Chlorophora excelsa) and Parassolier (Mussanga cecropioides). The soil block test procedure was conducted according to ASTM D2017-81 standard. A classification scheme based on above ground and ground contact end uses was developed. In addition the eight species were ranked using a Wilcoxon matched pair statistical test on SAS. Seven of the eight species investigated were susceptible to white rot fungi, while Iroko and African padauk were the only species highly resistant to brown rot fungi. Based on the end use classification scheme, Amouk, Frake, African mahogany, African padauk and Iroko all showed potential for above ground applications, while only African padauk and Iroko showed potential for ground contact applications.
P Nzokou, K Wehner, D P Kamdem


Diffusion treatment plants (Latin America - Africa)
1974 - IRG/WP 333
B N Prasad


A new accelerated field test for termites
1983 - IRG/WP 1178
A new accelerated field test method for termites is described. Two series of tests were conducted with this accelerated method and the results were very encouraging.
W E Conradie, A Jansen


Leaching of CCA from Pinus patula during marine trials in the southern hemisphere
1991 - IRG/WP 4167
Pinus patula stakes were treated with CCA to retentions of 31 kg/m³ salts, and were sited in the sea of Port Alfred, South Africa, for two years. Samples were then removed to the laboratory and analysed as before for copper and arsenic. Prelimiary data showing CAA losses from these stakes in the marine environment showed that CCA was longitudinally leached from them, and was also transversly redistributed in them.
G D Shelver, C D McQuaid, A W W Baecker


The geographical distribution of the house longhorn beetle Hylotrupes bajulus (L) Serville (Col., Cerambycidae). An attempt at a cartographical compilation of existing data
1978 - IRG/WP 176
The larvae of the house longhorn beetle belong to the most economically important pests of softwood in service in most European countries and also in some areas overseas. I have reported earlier regarding the history, the question of where the pest originally came from, and concerning attacks in earlier and recent times (1968, 1970, 1974, 1976). In this report an attempt has been made to compile cartographically the currently existing data.
H Becker


The foreign exchange situation and fate of wood preservation in Nigeria
1989 - IRG/WP 3558
Up to about 15 years ago, wood utilization industry in Nigeria gave no serious thoughts to wood preservation. After this period however, as a result of escalated local demand for sawn timber, logs with wider sapwood and mainly of secondary tree species requiring protection of the sawn timber became dominant in the local timber scene. Preservatives both for protection in and out of ground contacts were available in the past in the market and at affordable prices. However, the value of local currency which has depreciated by about 86% within 48 months has made importation of preservatives a very expensive business. The paper suggests both short-term and long-term solutions for tackling the assult on the forest conservation programme which lack of wood preservation strategy has occasioned in Nigeria.
M A Odeyinde, S C Ifebueme


Chapter 2 - Introduction to world bamboo
2007 - IRG 07-10635-02
In this chapter the bamboo species of the whole world along with local name, bamboo type, flowering type, locality and uses have been presented in 20 different Tables.
A K Lahiry


Kiln drying of poles as a means of solving the problems of pre-treatment decay in poles
1985 - IRG/WP 1263
The concept that pre-treatment decay can cause wide variation in the treatability of wood and especially wood poles has caused much discussion and debate in wood preservation circles. Yet it seem only logical that if decay has effected the strength characteristics of the wood and caused a differential moisture content in the wood the treatment of the end product will be highly variable and the longevity of the product will be unpredictable. Quite simply the one proven solution to the problem seems to be to artificially season the wood, usually by kiln drying, prior to treatment. This paper briefly reviews 1984 observations of the success of one treating operation in the Republic of South Africa in reducing the deterioration found during proof loading of all the poles produced. A literature survey is included to review the research accomplished to date to show that the results are truly valid. It is hoped that this paper will serve as a literature reference to other researchers in this subject and that they will contribute their findings to the work of the working group on pre-treatment decay in wood.
J A Taylor


Surface accumulation of copper on CCA-impregnated Pinus patula stakes during marine preservative trials in the southern hemisphere
1992 - IRG/WP 92-4181
Pinus patula stakes treated with CCA to target retentions of 30 kg/m³ salts were exposed to sea water in marine and estuarine ecosystems off the coast of Southern Africa for two years. Samples were then analysed for copper and arsenic. Analysis of samples from the marine ecosystem showed (IRG/WP/4167) that arsenic was longitudinally and transversely leached from the wood, whereas the copper was redistributed to the surfaces of the wood. Recent analyses have now confirmed that similar trends of copper mobility occurred in Pinus patula exposed to the estuarine ecosystem, i.e., copper levels within the wood decreased while the levels of the exterior zones of the wood increased correspondingly.
G D Shelver, C D McQuaid, M Tarin, A A W Baecker


Revised South African standards for wood preservation: Protocols for approval of wood preservatives
1995 - IRG/WP 95-20072
In 1994 the South African timber treatment industry completed its revision of the South African Bureau of Standards (SABS) Code of Practice for the preservative treatment of timber. These revisions were undertaken in parallel with changes to the SABS specifications for preservative treated timber. As a result of shortcomings in the previous wood preservative classification system which was based on exposure conditions for treated timber, the hazard classification for wood preservatives in force in South Africa has changed. The paper details the newly adopted classification system and its role within the current legislation requirements. Specific reference is made to the performance and toxicological data required for registration of a wood preservative in South Africa. Requirements in terms of an industry-approved South African Bureau of Standards (SABS) standard "product" specification and compliance with the SABS standard "treatment" specification are also discussed in more detail. Existing test requirements, protocols and procedures for approval of new wood preservatives are summarised. In addition, the paper identifies possible changes that could lead to more appropriate testing and acceptance procedures which reflect the real preservative needs of the various hazard classes.
D Conradie, P Turner, W E Conradie, A D Currie, I S J Burger


Wood preservation in Southern Africa
1984 - IRG/WP 3320
This report deals with the status of wood preservation in the countries of Southern Africa, namely Botswana, Lesotho, Mozambique, Namibia, South Africa, Swaziland and Zimbabwe. It includes some data on the timber production from the forests of these countries, as well as detailing the state of the timber products industries in South Africa which is the dominant country in the field in the sub-continent. The importance of wood preservation in the region is discussed and the industry described. A list of organizations concerned with wood preservation has been given together with their terms of reference and a general outline of the research work in progress in the region. The legislation, standards and specifications in current use have been added and the report ends with a bibliography.
A Pizzi, W E Conradie, R Cockcroft


Termite taxonomy and distribution with particular reference to climate change in Africa
2010 - IRG/WP 10-10738
Termites constitute an integral component of various ecosystems in Africa. Termites are also amongst the most difficult of the insects to study because of their cryptic behaviour. There are around 2600 species of termites (Isoptera) in 280 genera which have been described worldwide and about 39% of the total termite species are found in Africa. Some termite species are well known pests of agricultural crops, forest trees, wood products and timber-in-service. Thus, they are responsible for considerable damage in building structures in Africa. Termite identification is crucial to understanding termite distribution and to develop an integrated termite pest management (IPM) system. Published literature on the taxonomy and distribution of termites in Africa with particular reference to climate change is scanty. Little is known about the effect of climate change on the potential distribution of pestiferous termite fauna of Africa, especially the wood destroying exotic species. This African termite review attempts to collate information on termite taxonomy, distribution and climate change and highlight the gaps in knowledge and challenges in Africa, which is the centre of origin of the Macrotermitinae. African economic important termite species will receive sufficient attention for identification and distribution compared to other termite species. The use of traditional identification methods coupled with molecular techniques promises to resolve some of the challenges in termite taxonomy and distribution with particular reference to climate change in Africa, will be discussed.
P O Y Nkunika, B M Ahmed Shiday, G W Sileshi, J R J French, P Nyeko, S Jain


Commercial Timbers of Kenya
2016 - IRG/WP 16-10876
The global timber trade has for years been too familiar with an assortment of available African timbers, reputed for their appearance in terms of colour, grain, pattern and durability. African forests are fast disappearing through over-exploitation as a result of demand for agricultural land. Kenya, the home of some of these valuable hardwoods, has been similarly affected, with its forest land cover declining from high 28% to a low 1.7% within the last 5 decades. Today Kenyan forests consist mainly of exotic fast-growing species (Eucalypts, Cypress and Pines), that supply the local demand for industrial timbers (utility poles, posts, construction timbers, pulp and paper, veneer and board materials). The furniture industry now relies on hardwoods imported from Central and Western Africa, Tanzania, Mozambique, Zimbabwe and S. Africa. The wood carving industry, with some 30,000 wood carvers engaged in the industry, still depends on hardwood species available locally. Being still a heavy consumer of fuelwood and charcoal, with indigenous hardwood species being preferred, it is to be expected that indigenous hardwood forests in Kenya will decline further, with fewer of what used to be a an extensive list of indigenous species that provided the source of commercial timbers of the country. The list of exotic and indigenous species presented in this paper, not exhaustive by any means, comprises mainly the common commercial species, with brief notes on appearance, properties, availability and uses There is a number of the lesser known species, about which little or no information is available, mainly used for artisanal work, fuelwood and charcoal.
R Venkatasamy


Imports of African logs, do they harbor wood-decaying alien fungi and bacteria that could become a potential threat at temperate latitudes? – First results
2018 - IRG/WP 18-10904
In this project we investigate the potential threat of alien wood-decaying fungal and bacterial species imported to Germany with logs from African countries. In a first approach we analysed fungal species on imported logs by identification of fruit bodies by DNA sequencing of the internal transcribed spacer (ITS) regions ITS1 and ITS2. First results revealed the existence of at least one alien fungus on the logs. As only few fruit bodies were found on the logs we also extracted DNA from mycelium and from wood samples from the outer sapwood layer. For these samples no clear sequences could be derived from direct sequencing of the obtained PCR products suggesting the presence of multiple species in the samples. We will now extended our investigations and do currently analyse whole DNA from mixed samples from each log with a next generation sequencing approach to describe the biome of total fungal and bacterial communities and identify species composition.
J Trautner, M Höpken, E Melcher


Environmental protection and long term in-service sustainability of preserved wooden poles is secured by non-toxic barrier protection system – History and case studies in South Africa
2018 - IRG/WP 18-50340
Non-toxic flexible sheeting systems have been developed to encapsulate the ground contact regions of preserved wooden poles and prevent their premature failure in South Africa since 1992 but the technology also has a long history of resistance by individuals with vested interests in the built-in redundancies of such poles. The concept has, however, been simultaneously validated by many independent research institutions worldwide and IRG itself formed a Working Group in 1997 to examine the role of the technology in wood protection. This paper reviews the work done over the past 25 years to validate butt-encapsulation of preserved wooden poles with inert impermeable materials as a proven technology that prevents the loss of preservative from, and subsequent decay of, the protected poles. The paper also presents the findings of four case studies to that effect in South Africa.
A A W Baecker


The Commercial Forestry and Forest Products Industry in South Africa – A brief overview
2018 - IRG/WP 18-50342
The presentation made by Mr Michael Peter, Executive Director of Forestry South Africa, provides insight into the commercial forestry and forest products industries in South Africa. The forestry industry in South Africa is based solely on the propagation of exotic trees, grown in plantations in the higher rainfall regions of South Africa. The presentation shows the ownership, geographical extent and distribution of plantations. It presents this by genus and by management objective and it provides a summary of the key products produced from these plantations in the processing sub-sector. The contribution of each of these products in turn, to the overall economic contribution of the sector, is also presented. The presentation demonstrates the disproportionately (relative to its land and water footprints) large economic, social (employment) and environmental contribution of the commercial industry to South Africa, including its contribution to the Gross Domestic Product of the country, through export earnings. The physical, regulatory and political challenges which have led to the shrinkage (geographic) of the Industry and which have hindered the achievement of the country’s stated growth objectives for the Industry, are discussed in some detail. The physical, regulatory and political challenges which have led to the shrinkage (geographic) of the Industry and which have hindered the achievement of the country’s stated growth objectives for the Industry, are discussed in some detail.
M Peter


An overview of The Wood Preservation Industry in South Africa
2018 - IRG/WP 18-50343
South Africa boasts a total land area of 1,22 million km2 or 122 million hectares of which approximately 1% is cultivated with commercial plantation forests. The species planted are exotic species i.e. pine, eucalyptus and wattle. The commercial forests supply raw material to a diverse forestry sector and industries including Paper and Pulp, Sawmilling, Mining Timber, Poles, Charcoal, Wood chemicals, Fibre and Textiles, etc. Timber preservation in South Africa was first introduced in the early to mid-1900s when the degradation of structural timber by wood destroying insect started occurring in buildings at a scale of economic concern. Apart from subterranean termites native to southern Africa, that was also a cause of some of the destruction, further destruction by wood borers and dry-wood termites not native to our shores became an increasing problem, especially around the time of the Second World War. The arrival and spread of alien wood destroying agents to our coastal and inland areas lead to the introduction of regulations and standards for the treatment of timber and the use of treated timber in South Africa since 1946. Regulations and standards pertaining to the sale and used of treated timber has been in existence since then although under varying regulating and government authorities. In the early 1960s regulations were also taken up in building regulations and standards, and other regulations related to registration of wood preservatives as agricultural remedies and the use thereof has also become applicable. The timber preservation industry as a subsector is a small part of the total forestry sector, and it is estimated that between 1.3 to 1.5 million m3 of timber in total is preservative treated at ± 115 timber treatment plants spread all over the country, with the majority situated in the commercial plantation forest regions of Kwa Zulu Natal, Mpumalanga, and Limpopo. The treatment plants produce a limited variety of treated timber products ranging from mostly sawn and machined timber used in construction, landscaping and leisure applications as well as poles used for utility lines, agricultural purposes, fencing and building and construction etc. As such the majority of plants fall under the category of treatment plants integrated with Sawmilling or as Wood pole treatment plants. Because of the climatic and geographical exposure and end application and market demands and needs, the wood preservatives used in South Africa remain predominantly CCA and Creosote with a very limited volume of timber being treated with other preservatives including waterborne preservatives such as borate and CuAz, and Azole Permethrin based LOSP preservatives. The local timber preservation industry is mostly self-reliant with regards the local supply and manufacture of the two main preservative types, i.e. CCA and Creosote as well as timber raw material sourced mainly within South Africa and also from Swaziland and Zimbabwe. South Africa and its people, in relation to many other countries, do not utilize timber, including preservative treated timber to its fullest potential. This can in part be explained because of a culture of steel, concrete, stone and brick and mortar deeply entrenched into our societal frame of reference over the last 350 or so years. In addition a limited volume of raw material available from the overall local timber resource cultivated is destined for building and construction purposes.
Bruce Breedt