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Evaluation of two populations of Reticulitermes santonensis De Feytaud (Isoptera) by triple mark-recapture procedure
1997 - IRG/WP 97-10237
The optimisation and use of biocides is linked to the improvement in our understanding of the target organism. With this in mind we have studied 2 populations of the termite Reticulitermes santonensis De Feytaud. The first inhabiting an urban territory, the trees lining Ave. Boutroux in Paris. The colony has been estimated at 1,200,000 +/- 130,000 insects by triple mark-recapture procedure, foraging a surface of 1080 m2. The area containing visible damages in the trees is of 2,100 m2. The greatest distance covered by an individual is 65 m in 18 days. The second is a field population at Fondette near Tours. The zone studied is of 2,500 m2, the colony being estimated at 230,000 +/- 14,000 insects, foraging a surface of 145 m2. The greatest distance covered by an individual is 40 m in 13 days. This study shows that a termite worker can cover a considerable distance in a short time and that the colonies themselves seem to move within a zone that they cannot totally exploit permanently.
I Paulmier, B Vauchot, A-M Pruvost, C Lohou, M Tussac, M Jéquel, J-L Leca, J-L Clément


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


Estimation of effective diffusion path lengths in wood by swelling studies
1989 - IRG/WP 3524
The effective average distance that a solute must diffuse to penetrate the cell wall matrix following pressure treatment is estimated from the rate of swelling of wood, vacuum treated with water. It is assumed that the diffusion paths are similar for water and a solute such as a wood preservative component. Since bound water diffusion coefficients for water in wood have been estimated by others, the effective path lengths (Le) can be estimated. Effective average path lengths are estimated for red pine (Pinus resinosa), Southern yellow pine (Pinus sp), trembling aspen (Populus tremuloides) and soft maple (Acer rubra) sapwood and red oak (Quercus rubra) heartwood samples. The estimated path lengths are shortest for the softwoods, and longest for the ring porous oak. The results reflect the different patterns of cell penetration and different densities of the wood species.
P A Cooper, R Churma


Estimation of the population of a sound colony of Coptotermes lacteus (Froggatt)
1988 - IRG/WP 1353
Selecting an area with a high termite hazard is deemed essential in locating field sites in order to screen potential termiticides and wood preservatives. Yet, quantifying termite populations in such sites remains imprecise. There are major problems associated with estimating populations of termites in mound colonies (either free-standing or in trees), and these are briefly discussed. In this paper we estimate the population of a mound colony of Coptotermes lacteus as 3.06 x 105. The estimate relates to foragers collected at baits that had been inserted into the mound. The technique adopted, "removal sampling", did not destroy the integrity of the mound nor incur unnecessary expense.
D M Ewart, J R J French


The proposal for optimalization of the agar-block method for wood preservatives fungitoxic evaluation
1995 - IRG/WP 95-20065
On the base of own research and other scientists results the proposal for optimalization of agar-block method was presented by: - selection of test fungal species and strains and central distribution of their pure cultures, - change of the treatment and control samples exposure procedure, - application of mathematical estimation of toxic value results, - shortening the duration of fungitoxic test by miniaturization of wood samples.
J Wazny


Estimation of oral toxicity of boron as a bait toxicant and the trophallactic effects between individual members of termite colonies.
2003 - IRG/WP 03-10495
In recent years, because of the favourable environmental characteristics of boron, researchers in the wood preservation industries have refocussed on the use of boron as a major wood preservative against wood-destroying insects. Currently the greatest use of boron compounds is in remedial treatments. Boron has been found to have slow-acting toxicity against subterranean termites. Because of this characteristic, boron compounds may also be used as termite bait toxicants. The effect of boric acid on an individual donor termite was investigated in laboratory bioassays Trophallactic transfer of boron by these individual termites to other orphaned group of termite workers was conducted and the effects on the recipient groups recorded. It was believed that, this sequence of tests would provide a greater understanding of the carrying ability of ‘bait toxicant’ by individual termites, and allow estimates of the threshold toxicity of boric acid and termite survival rates to be determined. The bait matrix was Eucalyptus regnans F. Muell sawdust impregnated with various formulations of boric acid solutions in the laboratory. The result suggests that the toxicity of boron is dose dependent and it critical for the termites to ingest sufficient amounts of boron. But the mode of toxicity of boron has not yet been fully explained.
B M Ahmed


Toxic value estimation of wood preservatives by using the probit analysis
1990 - IRG/WP 2348
As it was assumed from previous experiments, the probit analysis appears to be the most suitable method of all used to estimate the toxic value of wood preservatives. With the help of the classical agar-block method the probit analysis was tested for its suitability in: 1) fungitoxic value estimation of the WR-3 preservative (quaternary ammonium compound + borate), as compared to different test fungi (Coniophora puteana, Gloeophyllum sepiarium, Lentinus lepideus, Poria placenta, Serpula lacrymans), and 2) in leaching value estimation by the mycological method (Coniophora puteana)
J Wazny, K J Krajewski


NIR spectroscopy for rapid estimation of decay resistance
2004 - IRG/WP 04-20294
In Scandinavia Scots pine (Pinus sylvestris L.) is an important commercial tree species. Its heartwood has traditionally been used in constructions exposed to risk of decay. In a laboratory experiment Scots pine wood specimens sampled from inner heartwood, outer heartwood and sapwood were exposed to the brown rot fungus Poria placenta. In general outer heartwood was more resistant than inner heartwood, but there were variations even within the same wood zone. NIR spectra obtained on solid wood prior to decay testing were used in multivariate calibrations to predict decay resistance of heartwood. Results from segmented cross validated partial least squares (PLS1) regression modelling showed that resistance to decay in Scots pine heartwood could be predicted with satisfying precision using NIR spectroscopy. As NIR spectra were collected on solid wood, development of the method for industrial use is potentially possible.
P O Flæte, E Ystrøm Haartveit


Above-Ground Durability Estimation in Australia. Results after 16 years exposure
2005 - IRG/WP 05-20314
A program of research was established in 1987 to examine the above-ground durability of a selection of timbers that are commercially significant in Australia. Test samples were assembled in an L-Joint design and placed on exposure racks in a format to replicate joinery that is exposed to the weather above ground. Both painted and unpainted material has been exposed. Test samples have been evaluated regularly over the sixteen-year exposure period, and although the trial is not yet complete, the research has highlighted and provided data on the effect of painting, the source of timber and the influence of location. Biodeterioration models are now being developed and as the exposure approaches completion, the models will be further refined using results that emerge for the more durable softwoods and hardwoods that are incorporated into the project. As data is finalised for a particular species, it is to be submitted to the national standard for timber durability as well as design for durability programs currently underway in Australia.
L P Francis, J Norton


Experiences with the OECD guideline proposals for the estimation of emissions from preservative-treated wood in the environment
2004 - IRG/WP 04-50209
The practicability of 2 CEN proposals for OECD guidelines on the estimation of emissions from preservative treated wood by laboratory methods for either wood held in storage after treatment and for wooden commodities that are not covered, and are not in contact with ground (guideline 1) or wooden commodities that are not covered and are in contact with ground, fresh water or seawater (guideline 2) was tested during a research project in Germany. The influence of several test parameters was investigated for different types of preservatives, i.e. duration of the dipping time for guideline 1 experiments as well as size and surface structure of the specimens, comparability with EN 84 experiments and the influence of the ratio of the water volume per emitting surface area in guideline 2 experiments. Parallel tests in two laboratories allow the assessment of the repeatability of the laboratory tests. The results of the experiments with a solvent based preservative containing propiconazole are presented and compared with experiences from field experiments. The emissions were lower if less water was available per surface area and time. Different specimens yielded similar losses per surface area and the results from leaching experiments according to EN 84 were similar to the results from guideline 2 experiments. Emission rates and total losses can be estimated according to the calculation model of the OECD ESD for Wood Preservatives. Calculated data fit the experimental data. Emission rates of propiconazole estimated in guideline 2 experiments were generally higher than losses by natural rain. Minimum emission rates in these experiments were similar to the maximum values estimated in the field experiment. Losses by guideline 1 experi¬ments were in the range of the field data.
U Schoknecht, R Wegner, E Melcher


Detection and estimation of Hylotrupes bajulus L. wood damages by ultrasonics
1990 - IRG/WP 2350
To evaluate the validity of the ultrasonic application in the detection and evaluation of wood damages produced by Hylotrupes bajulus L. larvae, some laboratory tests were made with small wood samples. The pulse through transmission method was used. The transit time of ultrasonic pulses in transversal sections, radial and tangential, of the samples was measured. The increment of the transit time of ultrasonic pulses with respect to clear wood gave to this method the way to estimate the damage grade.
G Prieto


Estimation of mycelial biomass by determination of the ergosterol content of wood decayed by Coniophora puteana and Fomes fomentarius
1989 - IRG/WP 1415
The mycelial biomass of fungi decomposing wood materials may be estimated by the use of an ergosterol assay technique.ln decay tests, essentially according to EN 113, estimates made by HPLC analyses on wood decayed by Coniophora puteana and Fomes fomentarius show the increase in biomass in the wood blocks. The ergosterol contents were correlated with dry weight loss determinations. Degradation of wood in relation to colonization is discussed.
K Nilsson, J Bjurman


Estimation of the impregnation degree of pine wood by the distribution analysis of active ions concentration in the cross-section
1999 - IRG/WP 99-20174
Samples in the form of pine wood rollers of diversified moisture content of ca. 50, 28 and 12% were impregnated with a water solution of the mixture type CCB with the use of the full-cell process. Moisture content was determined in individual layers from the girth to the pith. In the same way the concentrations of copper and chromium ions with the use of the spectrophotometric method and recalculated to the total dry mass of the preservative. Simultaneously, there was performed biological test according to EN 113 for the investigated mixture and different concentrations: 0,1; 0,16; 0,25; 0,4; 0,63; 1,0; 1,6; 2,5. The obtained fungicidal value let to determine the depth of biological resistance of impregnated wood within the impregnated zone.
K Lutomski, B Mazela


Determination of fungitoxic value of preservatives in laboratory wood-block tests. Part 2: Statistical estimation
1989 - IRG/WP 2327
Laboratory modified agar-block tests were made to determine the fungitoxic value of the wood preservative CCA against the test fungus Serpula lacrymans using statistical methods. With the aid of statistical computer programmes based on the least square method. the regression equation was found for the dependence between sample mass loss and preservative retention both in terms of percentage and following probit, decimal and natural logarithmic transformations. The fungitoxic value was found to be lying in the point of intersection between the lines calculated and that of a 3 per cent mass loss. The application of mathematical statistics seems to have increased the objectivity and repeatability of measurements of fungitoxic value in the case of this wood preservative.
J Wazny, J D Thornton, K J Krajewski


Comparison of laboratory tests and field experiments for the estimation of emissions from treated wood
2005 - IRG/WP 05-50224-6
The authorisation procedure for biocidal products according to the European Biocides Direc¬tive in¬cludes the assessment of possible environmental risks by the emission of ac¬tive ingre¬dients. This needs an input of data on the expected emissions of biocides into environmental com¬part¬ments. The procedures for the estimation of these emissions should be harmonised. La¬boratory test proce¬dures as proposed by the CEN TC38 WG27 might be a suitable means to obtain emis¬¬sion data. However, laboratory data cannot directly represent variable service con¬ditions. Only a limited number of the en¬vi¬ron¬mental conditions that can influence the emis¬¬¬sion of bio¬cides are represented in the la¬bo¬ratory tests. Never¬theless, water contact is a crucial factor for the emission of sub¬stan¬ces into water that can be controlled under labo¬ra¬to¬ry conditions. Al¬though there are only few studies that directly compare biocide emissions in laboratory and field ex¬pe¬riments it is helpful to summarise literature data for active ingre¬dients that have been ex¬ten¬sively investigated. Emission data from different types of experi¬ments are summa¬rised. Limitations and benefits of laboratory tests and field experiments as well as the resulting con¬se¬quences for the assess¬ment of emission data are discussed. Finally, it will be necessary to com¬promise about the suitability and repeatability of the test pro¬cedures and the applicability of the test results to different environmental conditions.
U Schoknecht


A review of the current status of the estimation of emissions from preserved wood and their use in the environmental risk assessment of wood preservatives under the Biocidal Products Directive
2005 - IRG/WP 05-50224-7
A review and update of the status of the issues concerning the estimation of emissions from preserved wood (e.g. amendments to the proposed ‘OECD Guidelines’), and the environmental risk assessment of wood preservatives under the Biocidal Products Directive (e.g. compartmental sizes, emissate ecotoxicity testing).
E F Baines


Direct estimation of the durability of high-pressure steam modified wood by ESR-spectroscopy
2010 - IRG/WP 10-40508
Heat generated persistent free radicals have been detected by electron spin resonance measurement of thermally modified wood, prepared by high pressure superheated steam treatment. The specific density of these radicals have been correlated with the durability against basidiomycetes, as measured by the European standard EN113 test. In the lower range of specific radical densities, the found correlation has revealed non-specificity for six different wood species, for two different treatment intensities and within different tree zones. This result promises a great potential for electron spin resonance to estimate the durability of high pressure steam modified wood. It also provides evidence for an antioxidant mechanism, responsible for the durability enhancement in heat treated wood.
W Willems, A Tausch, H Militz


Comparison of laboratory and semi-field tests for the estimation of leaching rates from treated wood
2010 - IRG/WP 10-50274
The authorization of wood preservative formulations in the European Union according to the Biocidal Products Directive (BPD) includes the assessment of environmental risks by the emission of active ingredients. This risk assessment includes scenarios for preserved wood (e.g. house scenario, noise barrier), in which the predicted environmental concentration (PEC) for soil and water is calculated, using an emission or leaching rate for the active substances from the treated wood. The leaching rate is the most important starting parameter to determine the PEC value for different scenarios in the soil and water compartment. In this paper we compare leaching rates derived from well accepted laboratory and field studies for copper and boron from pressure treated wood. This comparison demonstrates that the recommended laboratory studies do not require additional correction factors for simulation of realistic worst case emissions from treated wood. In contrast, for the active substances reviewed, the laboratory tests overestimated leaching rates both for short and long-term exposure times as compared to the leaching rates obtained in field studies.
N Morsing, M Klamer, B Seidel, J Wittenzellner, M Maier, J Habicht


Estimation of foraging territories of Microcerotermes diversus Silvestri (Isoptera: Termitidae) in Ahwaz (Iran)
2010 - IRG/WP 10-10744
Microcerotermes diversus Silvestri (Isoptera: Termitidae), an important wood pest in Ahwaz (Khuzestan, Iran), causes serious economic damage to wooden products in buildings. In this study, the foraging territories of this subterranean termite have been determined by mark-release-recapture technique. Estimated foraging territories for colonies A and B were 25.59 and 44.16 m2, respectively. The maximum and minimum linear foraging distances (m) were 5.40 and 2.14 for colony A and 9.14 and 1.86 for colony B, respectively. Our data extend knowledge about the biology, ecology and behavior of this termite. This information can aid us in evaluating the effectiveness of control methods, and thus can be used to improve management techniques.
B Habibpour, F Kocheili, M Ekhtelat


Estimation of service life of treated wood in ground contact based on early indicators
2013 - IRG/WP 13-20536
A well-known problem with field testing is that it takes a long time before meaningful and reliable results are achieved. Only when a trial has come to an end the so called average life for the samples in a group can be calculated and compared with other samples. The aim of the present study was to investigate if it is possible to get a reasonable and good estimation of the average life long before a trial has come to an end. In order to get early stage results five early indictors were identified. Values for these indicators were calculated for a large number of trials. Estimated average lives (EAL) were calculated with help of single and multiple regression analyses and compared with actual average lives. The results are presented as ccoefficients of determination (R2) between the different early indicators and the average life of the trials as well as diagrams showing the calculated EAL compared to average life according to the standard EN 252. For some groups of test fields and preservatives the correlation and estimations are very good while they are worse in other cases. The study has confirmed that it is difficult to find a general method, based on early indicators, to estimate the average life of different types of preservative-treated wood tested in field trials according to EN 252. However, the calculation model is promising as in some cases the estimated average life shows a good correlation with the average life according to EN 252, which indicates that further efforts to improve the model seem worthwhile.
M Hansson, J Jermer, P Larsson Brelid, N Terziev


New approach to improve the estimation of colony population in subterranean termites (Blattodea: Rhinotermitidae)
2016 - IRG/WP 16-10866
The aim of this study was to estimate the mortality and fading effects of dye markers Neutral red and Nile blue commonly used in the estimation of termite colony population, in order to determine the decrease rate from the initial number of marked and released termites. This rate can be considered in the application of the different indexes used to calculate the number of termites of the colony. In the laboratory, Reticulitermes grassei Clément, 1977 were forced-fed during four days with Neutral red 0.5% (wt/wt) and Nile blue 0.5% (wt/wt); later the percentage of mortality and fading was recorded after 30, 40, 60, 80 and 137 days post treatment. These allowed us to obtain a fitted linear regression line that can be used for estimating the number of termites that remain marked into the colony at any day. The percentage of mortality observed increased from 3.17% at 30 days to 18.07% at 137 days for the Neutral red dye and from 8.62% at 30 days to 21.89% at 137 days for Nile blue. No fading was observed at 30 and 40 days for Neutral red and until 60 days for Nile blue, but increased from 10.59% at 60 days to 34.68% at 137 days for Neutral red and from 5.94% at 80 days to 12.49% at 137 days for Nile blue. A field estimation of the colony population was made in two colonies from Palenciana town (Córdoba, Spain) using the Lincoln index. The colony population was estimated twice, first considering the total number of marked released termites and later taking into account their decrease (by mortality and fading) in relation with the days elapsed since their release into the colony, estimated with the linear regressions obtained.
E Alcaide, R Molero, J Diz, M Gaju


Estimation of wood degradation determined by visual inspection, mechanical testing and DNA characterisation – report after 3 years of exposure
2016 - IRG/WP 16-30700
The influence of two separate treatments, thermal modification and alkaline copper quaternary (ACQ, Silvanolin©) treatment, on fungal decay, visual disfigurement, deterioration in mechanical properties and fungal community structure was assessed on Norway spruce (Picea abies) and compared with the performance of two naturally more resistant tree species native to North America: Douglas fir (Pseudotsuga menziesii) and Western red cedar (Thuja plicata). Wood samples were exposed to environmental conditions and collected annually over three years. Samples were visually examined and rated for decay and disfigurement then evaluated to failure in three-point loading to determine flexural properties and, finally, DNA was extracted from the samples and analyzed to determine the fungal community present. As expected, there were substantial differences in visual ratings, fungal colonization and flexural properties. Further assessments are planned.
N Thaler, T Martinović, M Bajc, D Finžgar, H Kraigher, A Sinha, J J Morrell, M Humar


Estimation of residual compressive strength on cross laminated timber with biodeterioration damage
2021 - IRG/WP 21-40918
CLT is susceptible to biodeterioration such as fungal decay and termite attack during long-term use for buildings. It is necessary to know the residual strength performance of biodegraded CLT for estimating future performance and aging of CLT. In this study, compression tests of CLT damaged by brown rot fungi and termites were conducted to clarify the relationship between residual strength and mass loss rate. The relationship between strength and defect rate of effective area (parallel layer’s area) calculated from CT scan data was also investigated. As a result, it was found that there is a negative correlation between the defect rate of the effective area and the strength, regardless of whether the deterioration factor is decay or termites, and this relationship may be used to estimate the residual strength. In the case of termite-damaged specimens, a low correlation was found between residual stress and mass loss rate, suggesting that it is difficult to estimate residual strength from the mass loss.
R Inoue, T Mori, K Kambara, W Ohmura