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Biological Durability of Laminated Veneer Lumber from Durable and Non-Durable Wood Species
2005 - IRG/WP 05-10567
Laminated Veneer Lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.
P Nzokou, J Zyskowski, S Boury, D P Kamdem

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

Thermal modification of non-durable wood species 1. The PLATO technology: thermal modification of wood
1998 - IRG/WP 98-40123
The PLATO technology is an innovative upgrading technology with low environmental impact, which can be applied to fast grown and non-durable wood species. This technology is based on a thermal modification of solid wood without the addition of chemicals (e.g. preservatives), consisting of a hydrothermal treatment, followed by drying and curing. The PLATO technology results in a substantial improvement of the natural durability and dimensional stability of wood with only a slight reduction in mechanical properties. Applications of thermally modified wood will include areas where a good durability and/or dimensional stability is required, e.g. garden wood and furniture, wooden sheds, canal lining, joinery, window frames, doors, claddings. In 1998/99 the PLATO technology will be commercialised in the Netherlands. In this paper features of the PLATO technology will be discussed, including selection of wood species, the PLATO process and product development, product properties and applications.
M J Boonstra, B F Tjeerdsma, H A C Groeneveld

Severe decay damages of bridges made of ekki (Lophira alata) wood known as a durable species
2000 - IRG/WP 00-10383
Bridges made of ekki (azobe, bongossi, Lophira alata Banks et Gaertn.) timbers were severely decayed only 10 years after the construction possibly caused from no maintenance for the periods. The reason of no maintenance is due to the misunderstandings on wood durability against wood-decaying fungi. Some civil-engineers and architectures understand "durable species" means "absolutely decay-durable species." They recently like to use durable wood species imported from abroad instead of domestic wood treated with preservatives because Japanese policies and civic insistences avoid to use wood preservatives to maintain natural environment and human health. This paper deals with the details of the typical decay damages of wooden bridges.
S Doi, T Sasaki, Y Iijima

Thermal modification of non-durable wood species 2. Improved wood properties of thermal treated wood
1998 - IRG/WP 98-40124
Properties of wood treated in a new heat-treatment process called the PLATO-process have been studied. Several wood species have been treated using this new thermal modification process using a range of process conditions (mainly time and temperature). In this study the characteristics of the treated wood were determined using samples from whole planks treated on pilot plant scale. The modified chemical structure of the wood after treatment results in a product with improved properties. The most important properties of wood, strength, dimensional stability and durability, were determined before and after the heat-treatment. The examined wood species showed a minor loss of strength after treatment. The correlation between the hygroscopicity of the treated wood in moist conditions and the dimensional stability has been studied. Depending on the applied process conditions the hygroscopicity of the treated wood decreased. The hygroscopicity was reduced by 40% and the dimensional stability appeared to have an improvement, ranging to 50%. The durability after heat-treatment was substantially improved.
B F Tjeerdsma, M J Boonstra, H Militz

Possible durability transfer from durable to non durable wood species. The study case of teak wood
2001 - IRG/WP 01-10392
Teakwood is well known for its excellent natural durability, mostly due to its high proportion of extracts. Amongst these extracts, quinones, and more precisely some naphtoquinones (such as lapachol) and anthraquinones (such as tectoquinone) appear to play a crucial role in the resistance to wood decay organisms. At a laboratory scale, sawdust from malaysian teak heartwood has been extracted under different temperatures. These extracts, as well as solutions of commercialised lapachol and tectoquinone were used to treat pine sapwood mini blocks. Such treated and leached samples were used for accelerated fungal tests using basidiomycetes. The results have shown that protection against fungi was achieved through these treatments. Nevertheless, laboratory extracts from teakwood and commercial quinones performed differently, arousing then questions on this way of preserving non durable wood species.
M-F Thévenon, C Roussel, J-P Haluk

Feasibility study on three furfurylated non-durable tropical wood species evaluated for resistance to brown, white and soft rot fungi
2008 - IRG/WP 08-40395
Furfurylation can protect non-durable wood species against biological degradation, but the method used today cannot fully protect the heartwood of Scots pine due to insufficient penetration. In order to test alternative wood substrates for furfurylation, three Malaysian grown wood species (Kelempayan, Rubberwood and Sena) were furfurylated and subjected to soil block decay testing. Their performance was compared to furfurylated Scots pine and furfurylated Beech modified using the same process. In addition, treatment characteristics were evaluated. One of the species tested, Kelempayan, seems to be a promising substrate for furfurylation. Kelempayan is easy to impregnate in both sap- and heartwood, and a 50% higher weight gain was reached using equivalent amounts of impregnation solution compared to Scots pine. Sena, Rubberwood and Beech returned weight gains 40-60% lower than Scots pine. Decay protection was largely comparable at equivalent weight percent gains for all wood species tested, although differences appeared. Generally, a weight gain of approximately 25% by furfurylation seems to offer good protection in the chosen soil block test.
T Mark Venås, A H H Wong

Field Tests of naturally Durable North American Wood Species
2008 - IRG/WP 08-10675
There has been little field test performance data published on North American naturally durable species in general, and no published data on second growth material in particular. Yellow cedar (Callitropsis nootkatensis), western red cedar (Thuja plicata), eastern white cedar (Thuja occidentalis), and three wood species reputed to be moderately durable were installed in ground-contact (stakes) and above-ground (decking) field tests at test sites in British Columbia and Ontario, Canada and Florida and Hawaii, USA between the Fall of 2004 and Spring 2005. Where possible old growth and second growth material, with and without sapwood, were obtained and used in the testing. Results from ground-contact field stakes and above-ground mini-decks after 3 years exposure are presented. The test site with the fastest ground-contact decay rate was Florida. The fastest above-ground decay rate was seen in Hawaii. In general, yellow cedar was the most decay resistant, followed by the other two cedar species, then the three other species. There was no appreciable difference in decay resistance between heartwood samples from old-growth and second-growth western red cedar, yellow cedar, and larch (Larix occidentalis).
P E Laks, P I Morris, G M Larkin, J K Ingram

Above Ground Field Evaluation and GC-MS Analysis of Naturally Durable Wood Species
2012 - IRG/WP 12-10764
Nine wood species are being evaluated in above ground field studies in Mississippi and Wisconsin. Candidate naturally durable wood (NDW) species are being rated at yearly intervals for resistance to decay, cupping, and checking. Field ratings after 12 months exposure are presented. To date, Paulownia tomentosa (PAW) and southern yellow pine (SYP) are least durable and cedars are the most durable in above ground exposure. Wood samples are being taken from the deck-boards and subjected to chemical analysis using GC-MS. Fatty acids from NDW species were extracted, derivatized, and analyzed along with commercial fatty acid methyl ester (FAME) standards. With few exceptions, results indicate that FAMEs are more abundant in NDW species. However, preliminary bioassays found no inhibition of select wood decay fungi by FAMEs at naturally occurring concentrations.
G T Kirker, A B Blodgett, S T Lebow, C A Clausen

Use of the durable species Coast Redwood as a reference system for field testing of Wood Protection systems
2012 - IRG/WP 12-20486
Data is provided and discussed for a number of field exposure tests where the naturally durable wood species Coast redwood, Sequoia sempervirens, was included along with untreated pine and standard preservative treatments. In general, there is potential for higher variability of results with this naturally durable species, but it does suggest that redwood can be a useful reference material for testing systems for above ground applications, especially where long-term decay performance may not be as critical as overall product quality. Comparative performance of products to redwood heartwood at test sites with different climate indices and with different test methods may provide additional useful data on the relative performance of systems than when compared to only untreated pine sapwood and standardized preservative systems.
A Zahora, A Preston, L Jin

Transferable Durability: Enhancing decay resistance of non-durable species with extractives from durable wood species
2013 - IRG/WP 13-10808
Extractive content and composition is a vital component of naturally durable woods; however, variability in extractives can limit their usefulness in the field. Two extractive-free, non-durable wood species were pressure treated with ethanol-toluene extractives from 8 durable wood species. Extracted Southern pine, Paulownia and unextracted Southern pine blocks were treated and challenged in soil bottle experiments with four common wood decay fungi. Weight loss from fungal degradation of the extractive-treated blocks was compared to untreated controls. Results indicated that in some cases, treatment with extracts from durable wood species decreased the percent weight loss from exposure to decay fungi. Chemical analysis of extractives from these durable and non-durable woods was performed using GC-MS and chemical components were compared. Several unique compounds were found in the more durable species compared to less durable species.
G T Kirker, A B Blodgett, S Lebow, C A Clausen

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan
2016 - IRG/WP 16-10857
Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, Reticulitermes flavipes from four wood species from Pakistan (Dalbergia sissoo, Cedrus deodara, Morus alba and Pinus roxburghii) as well as Teak (Tectona grandis). Termites showed increasing levels of mortality with increasing concentration of heartwood extractive when exposed to extractive treated non-durable southern yellow pine (SYP) blocks in a force feeding test compared to SYP blocks treated with water or solvent (ethanol: toluene) only. Characterizations of heartwood extractives were performed using Gas Chromatography-Mass spectrometry (GC-MS). Chemical profiles were prepared for each wood species’ extractives and are discussed relevant to their termiticidal properties. Future work will focus on further isolation of bioactive compounds or synergistic groupages of bioactive compounds from these and other wood species for use as environmentally friendly insecticides/termiticides for wood and wood based materials.
M E Mankowski, B Boyd, B Hassan, G T Kirker

Coula edulis baill an unknown wood species as an alternative to the main durable wood species used in Gabon
2019 - IRG/WP 19-10945
The Congo Basin hosts an exceptional biodiversity of trees, flora and fauna. However, the immense natural heritage of the forests in this area is increasingly threatened by many anthropogenic factors, due to selective exploitation of certain wood species. In Gabon, whose ecosystem is representative of this area, the forest represents nearly 80% of the national territory. Only a minority of wood species is exploited because of their high market value (Ageos, 2015). The direct consequences of this selective exploitation are the decrease of the disponibility and even the eventual disappearance of certain wood species associated to the fast-growing international tropical timber markets. This is the case for kevazingo, which is classified as an endangered species and therefore prohibited from exploitation. In addition to these main exploited species, several less known species are available in Gabon. This is the case of the Gabonese hazelnut tree (Coula edulis baill), whose wood is used by local populations for its longevity because of its resistance to fungi, insects and more particularly termites. It is used to make forge coal and is used in the construction of huts such as posts and lintels (Moupela C et al, 2010-2013). In this context, it seemed interesting to study more in detail this species, having for the moment been the subject of little scientific investigations. The aim of this study was to investigate the natural durability of Coula edulis and the reasons of this latter one based on wood chemical composition. For this purpose, durability tests were carried out in Petri dishes on native and extracted samples of heartwood towards brown rot (Poria placenta and Coniophora puteana) and white rot (Coriolus versicolor and Pycnoporus sanguineus) fungi showing that unextracted samples presented higher durability to fungi. Fungal growth inhibition tests carried out with different concentrations of extractives confirmed their important fungicidal effects. Percentage of the different wood polymers and chemical composition of wood extractives were evaluated to find correlation between durability and wood chemistry. Results indicated that natural durability of Coula edulis could be explained by several reasons like the high density and hydrophobicity of its wood as well as its high lignin and extractives contents. Chemical analysis performed on extractives by GC-MS indicated the presence of gallic acid, quercetin and tannins.
C S A Bopenga Bopenga, S Dumarçay, P Edou Engonga, P Gerardin

Field performance of wood preservative systems in secondary timber species
1997 - IRG/WP 97-30152
The objective of this ongoing study is to evaluate the performance of new, potential, and standard wood preservative systems in secondary North American timber species. Eleven preservative systems were evaluated in this study - ACQ Type B, Copper Citrate 2: l, CDDC, chlorothalonil/chlorpyrifos, copper-8-quinolinolate, tebuconazole/chlorpyrifos, RH287, propiconazole/chlorpyrifos, copper naphthenate, CCA. and creosote. Field evaluations are being performed with ground contact field stakes and termite-specific testing in Hawaii, along with laboratory soil bed tests. The major wood species used with all the systems and evaluation methodologies are loblolly pine, northern red oak, tulip poplar, and cottonwood. More limited evaluations (field stakes only) are being conducted with eastern hemlock, red maple, and sweetgum. Information is presented from laboratory soil bed, field termite, and field stake evaluations. There is good correspondence between soil bed and field stake results. The more highly developed preservative systems and those in an AWPA P9 Type A oil carrier tend to perform better, and there can be a strong affect on performance from the wood species.
P E Laks, K W Gutting, R C De Groot

The susceptibility of 35 Amazon wood species to Cryptotermes brevis (Walker)
1982 - IRG/WP 1160
Laboratory tests were carried to evaluate the susceptibility of 35 Amazon hardwoods to Cryptotermes brevis (Walker). The results were analysed statistically and showed that five wood species were non resistant, nine were resistant and the other twenty-one in between those classes of resistance.
M D Canedo

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

Utility, deterioration and preservation of marine timbers in India
2005 - IRG/WP 05-40314
Timber is extensively used in India in the marine environment for various purposes due to its several advantages over modern materials. Infact, its use is increasing in recent years, finding wider and wider applications and this scenario is not going to change in the near future. Though, the bio-deterioration problem is found very severe in tropical waters, still indigenous methods are widely employed for the protection of fishing craft and the present level of chemical treatment is well below 5% of total timber used. This is due to socio economic problems of the potential timber user groups, unavailability of treatment plants in the coastal areas, lack of awareness in user groups, etc. In this paper, types of fishing craft used in the country, timber uses in the marine environment, bio-deterioration losses, research conducted on bio-deterioration aspects at various places and methods applied for the protection of wooden structures are presented.
B Tarakanadha, M V Rao, M Balaji, P K Aggarwal, K S Rao

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

The resistance of fifteen Indonesian tropical wood species to the powder post beetle Heterobostrychus aequalis
1990 - IRG/WP 1429
A preliminary laboratory test on the resistance of 15 tropical wood species to Heterobostrychus aequalis has been carried out using small samples of 7.5 x 5 x 1.5 cm³. The results reveal that Pinus merkusii and Agathis borneensis are very susceptible to Heterobostrychus aequalis. Other 13 species vary between susceptible to resistance There is no signifisant relation between starch content and the infestation of Heterobostrychus aequalis in the fifteen wood species.
Jasni, Nana Supriana

Natural durability and basic physical and mechanical properties of secondary commercially less accepted wood species from Brazil
2002 - IRG/WP 02-10451
The natural durability towards basidiomycete fungi and termites of several secondary timber from Brazil (Vatairea sp., Hymenolobium sp., Inga sp., Manilkara sp., Caryocar sp., Terminalia sp., Apuleia sp.) has been evaluated according to the EN 350-1. Some basic physical and mechanical properties (density, shrinkage, hardness, colour, static strength in flexion and compression) were also measured according to the appropriate standards. The results given in this paper could help in promoting the utilization of these timbers for certain end-uses.
M-F Thévenon, A Thibaut

Detection of trace organics by ion mobility spectrometry
1990 - IRG/WP 3635
Ion Mobility Spectrometry (IMS) is a time of flight analytical technique that is suited to detect chemicals in the low parts per billion range. Some of the advantages of IMS are: operation at atmospheric pressure, fast response time (0.1-10 sec), and the ability to characterize individual chemical species in complex matrices without any prior sample preparation. In this paper, the utility of IMS in providing a rapid, qualitative analytical technique for trace organics is reported for a number of application areas: narcotic traces on the hands of overdose victims, drug residues in body fluids, identification of wood species, detection of early decay in wood. The advantages and limitations of the use of IMS as a chemical sensor are discussed, and the application of mathematical models and algorithms to extract useful information from IMS signals are also be described.
A H Lawrence

Criteria for basidiomycetes testing and ways of defining natural durability classes
1998 - IRG/WP 98-20144
Within the framework of a European research project several laboratories have tested a series of 17 wood species covering the total range of natural durability. Basidiomycete tests are part of the total set up. Although generally based upon standard methods some minor differences in execution of the tests were evaluated for their impact on the results. This variation was superimposed with the fact that the tests were performed in different laboratories using wood from the same origin. Another important issue is the definition of natural durability classes for wood species starting from mass losses resulting from basidiomycete decay tests carried out under laboratory conditions. This paper summarises proposals for different ways to calculate or define the natural durability of wood and discusses some critical parameters in fungal testing, as well.
J Van Acker, M Stevens, J K Carey, R Sierra-Alvarez, H Militz, I Le Bayon, G Kleist, R-D Peek

Wood degradation mechanisms by the brown rot fungus Gloeophyllum trabeum
1997 - IRG/WP 97-10229
A mechanism for the degradation of wood by the brown rot fungus Gloeophyllum trabeum is outlined. The mechanism includes the function of redox-cycling, low molecular weight phenolic derivatives which sequester and reduce iron in acidic environments. The role of oxalate for the sequestration of iron (hydr)oxides and the pH dependent transfer of iron to the G. trabeum phenolic chelators, as well as for the maintenance of a pH gradient within the cell lumen and wood cell wall is discussed. A hypothesis for the generation of reactive oxygen species from the redox cycling of the phenolate compounds produced by G. trabeum as well as from free phenolics derived from the wood cell wall is outlined. Site specific production of hydroxyl radicals within the wood cell wall is discussed.
B Goodell, J Jellison

The effect of creosote and Basilit on the boards of 4 wood species against destructive fungi in Northern Iran
1989 - IRG/WP 3555
The results of the experiments conducted on the boards of maple, hornbeam, alder and beech, show that under the humid and moderate climate condition of Northern Iran, after 30 months, the witness samples were about 10% destructed by fungi, especially by Schyzophyllum commune and Coriolus versicolor. The impregnated samples by Creosote Basilite using Rueping and Bethell methods, were quite intact. There was no difference between these two chemicals. Among destructed boards, maple and hornbeam containing the most sugar and starch materials are more senitive than beech and alder. Until 50% destruction of witness samples, the experiments will follow up.
D Parsapajouh

Natural durability of European wood species for exterior use above ground
2003 - IRG/WP 03-10499
The main interest in using more timber for exterior constructions is to protect the environment, where wood is considered an environmentally friendly material. However, chemicals for wood protection are getting more and more restricted, consequently, the focus on the natural durability of wood is increased. Good, well-documented data on the durability of wood species in ground contact exist, which form the basis of the standard EN 350-2:1995. Yet, we have, however, no useful documentation for the natural durability of wood, when used outdoors above ground. The study is large-scale field trials, including more than 30 species, where the objective is to define and document the natural durability of European wood species when used outdoors above ground. The idea of the test set-up is to simulate different application situations of wood to recommend individual wood species for specific purposes – fit to purpose. Two basically different test set-ups are used: 1. Panels in close-to-practice applications: Horizontally oriented with and without covering. Vertically north turning and vertically south turning oriented with and without covering as well as 45 degrees south turning oriented without covering. 2. Lap-joints in standardised field exposures: The set-up is according to the CEN-standard ENV 12037: Wood Preservative – Field Test Method for determining the relative protective effectiveness of a wood preservative exposed out of ground contact – Horizontal lap-joint method. The paper presents the results of the appearance, the moisture fluctuation, mould growth and wood decay after 3 years field trial.
B Lindegaard, N Morsing

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