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Modelling of onset of mould growth for wood exposed to varying climate conditions
2009 - IRG/WP 09-20414
A performance-based service life design format based on climatic exposure on one hand and “resistance” of wood against mould growth on the other hand, is presented in this paper. A limit state for onset of mould growth is defined as the occurrence of traces of mould observed by microscopy. A dose-response model is proposed by which onset of mould growth can be predicted for an arbitrary climate history of combined relative humidity φ and temperature T. The model is calibrated and verified against a comprehensive set of experimental data published by Viitanen (1996) describing mould development on spruce and pine sapwood as a function of climatic exposure. The model is applied to predict time to onset of mould growth under natural outdoor climate (under shelter) as well as mould development in building attics and in crawl space foundations. The predicted response shows reasonable agreement with experimental observations and proven experience, although biological processes of this type display great variability. The results indicate clearly that a generally applicable, quantitative model can be used as a powerful tool for moisture design in practice. The model is designed to facilitate continuous improvement of prediction capability by further laboratory testing of various materials under specified climate conditions. It is concluded that the model in combination with currently available building physics software is suitable for moisture safe design of wood-based components in the building envelope. A further step should be to develop methods to manage uncertainties by introducing reliability and risk concepts into the service life design process.
S Thelandersson, T Isaksson, A Ekstrand-Tobin, P Johansson


Service life prediction of wooden components – Part 1: Determination of dose-response functions for above ground decay
2010 - IRG/WP 10-20439
Scots pine sapwood (Pinus sylvestris L.) and Douglas fir heartwood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 24 different European test sites under different exposure conditions (in total 28 test sets). The material climate in terms of wood moisture content (MC) and wood temperature was automatically recorded over a period of up to eight years and compared with the progress of decay. The final results of the study are presented within this paper. Significant differences among the test sites were observed regarding the time lag between the start of exposure and the onset of decay as well as the progress of decay. The overall aim of this study was to establish dose-response relationships between climate factors and decay as a basis for service life prediction of wooden components. The use of the combined material climatic parameters MC and wood temperature led to a feasible dose-response function and turned out to be a useful basis for service life prediction. How to apply this approach for estimating the expected lifetime of wooden components under various exposure conditions will be shown in part 2 of this series.
C Brischke, A O Rapp


Decay hazard mapping for Europe
2011 - IRG/WP 11-20463
In this study, two different dose-response models for above-ground decay as well as a model transferring macro climate data to wood climate data are presented. The models base on data from field trials, which had been conducted at 28 European test sites, and were used to calculate the relative risk for decay caused by climate variability in Europe. The two dose-response models give coherent results when using either measured wood climate data or simulated climate data. The potential to simulate the relative risk of decay for different sites in the world from climate data has been demonstrated, even if no measured wood climate data is available. A preliminary decay hazard map has been generated to illustrate the climate induced variability within the European continent. For comparative purposes also the Scheffer Climate Index (SCI) had been applied to the same European data base. It was concluded that valuable information for service life prediction of timber structures will be gathered from performance-based decay hazard estimation and mapping.
C Brischke, E Frühwald Hansson, D Kavurmaci, S Thelandersson


Service life prediction of wooden components - Part 3: Approaching a comprehensive test methodology
2011 - IRG/WP 11-20464
This paper is the third in a series on 'service life prediction' of wooden components and should be considered as a discussion paper. The authors tried to analyze the topic with a look from a distance and comment sometimes with a smile on the current controversial discussion about SLP issues. Nevertheless, the viewpoints of different groups, such as natural scientists, engineers, approval board members, consumers, and finally wood product manufacturers, have been described and resulting conflict points have been pointed out. Conceptual differences in modelling the performance of wooden components have been studied and related problems have been highlighted exemplarily on the base of 'hard' field test data. Problems related to the classification of wood durability are addressed as well as test methodological aspects. Finally a series of promising test methods and assessment procedures is presented. Moisture recordings in combination with subsequent dose assessments, comparative analyses of lab and field trials, and further new field test methods proved to have the potential to contribute to a comprehensive test methodology for wood based products. This is demonstrated based on preliminary results and summarized in a proposal for future test design requirements.
C Brischke, C R Welzbacher, L Meyer, T Bornemann, P Larsson Brelid, A Pilgård, E Frühwald-Hansson, M Westin, A O Rapp, S Thelandersson, J Jermer


Performance of Creosote/Chlorothalonil Preservatives
2011 - IRG/WP 11-30580
The addition of chlorothalonil to P2 creosote was found to increase the durability of southern pine in a series of ground contact stake tests. At retentions lower than those specified in the AWPA Standards, performance was increased when the creosote was amended with chlorothalonil. This indicates that lower creosote retentions may be required for as good or better ground contact when the amended systems is used. This would have the impact of reducing the environmental footprint of commodities treated with creosote.
H M Barnes, M G Sanders, G B Lindsey, T L Amburgey


Development of decay hazard maps based on decay prediction models
2016 - IRG/WP 16-20588
Durability plays a very central role in timber engineering, especially when working with wood in use class 3 and above where the risk of decay is high. As one of the primary decay influencing factors, the external condition, i.e. the local climate, is often graded by some type of climate index value. Predominately, climate indices are based on a direct relationship between weather data and decay. The aim of this paper was to develop a new type of climate index, including decay hazard maps, which explicitly considers the material climate. Firstly, the moisture content over time of a horizontal reference specimen was calculated using three different exposure models with weather data (rain, temperature, relative humidity) as input. Secondly, the output from the exposure models was post-processed using two different decay prediction models. Four different exposure model/decay-prediction model combinations were tested in total and repeated for many different locations in Northern Europe. Finally, the relative decay hazard between the different locations was calculated and interpolated, resulting in four preliminary contour plots visualizing the decay hazard in Northern Europe. The maps should be considered preliminary as they have not yet been verified against real decay data. The primary difference between the maps is the range of the relative decay hazard, i.e. the difference between the mildest and the most adverse conditions. The two extremes range between 0.6-2.6 and 0.8-1.8 respectively, which can be compared to the Scheffer index which ranges between 0.8-2.0. The next step, however not included in this article, is to compare the maps against real data.
J Niklewski, E Frühwald Hansson, C Brischke, D Kavurmaci


Modelling decay rates of timber exposed above ground on four different continents
2020 - IRG/WP 20-20670
Durability performance data from an international decking trial were analysed to explore relationships with climate variables, particularly those related to temperature and rainfall. Matched decking samples of slash pine (Pinus elliottii) sapwood and heartwood, spotted gum (Corymbia citriodora), Norway spruce (Picea abies) and Scots pine sapwood (Pinus sylvestris) were exposed to the weather above ground in Australia, Malaysia, Germany, Denmark and the United States. Boards were assessed periodically detect decay, which was rated using a common assessment scale. Preliminary exploration of relationships between decay assessment scores and decay indices – the Scheffer Climate Index and a dose-response model based solely on macroclimate variables – is presented in this paper. Shifting from a time-dependent analysis to one based upon cumulative macroclimate variables helped to better explain variations in performance among sites, although there were still some inconsistencies. Results are being further examined to help develop more precise predictive systems.
L P Francis, J J Morrell, C Brischke, P B Van Niekerk, J Norton


Studies into the effect of soil type and soil layer on the in-ground decay of European beech
2022 - IRG/WP 22-20681
In this study, European beech (Fagus sylvatica L.) specimens were exposed to three different soil types; Podsol (Podzol), Braunerde (Cambisol), and Pararendzina (Regosol), in adapted terrestrial microcosm (TMC) tests according to CEN/TS 15083-2 (2005). Soils were sampled (250 mm deep) from field sites and separated into their constituent layers to deliver three TMC setups; mineral soil layer only (“M”), mineral and organic layers (“OM”), and mineral, organic and litter layers (“LOM”), to identify the effect of each respective soil layer on wood decay. Wood specimens (5 x 10 x 100 mm³) were measured for oven-dry mass loss (MLwood) after 16 weeks of exposure, and compared to MLwood predicted using a dose-response laboratory in-ground decay model developed by Marais et al. (2021) for European beech. To deliver predicted MLwood after 16 weeks of exposure, input variables included soil water-holding capacity (WHCsoil) and soil moisture content (MCsoil) of the sampled soils’ mineral layer, as well as soil temperature (Tsoil) and exposure time. The MCsoil of TMCs were set to 95 % of the mineral soil layers’ WHCsoil. The non-parametric Wilcoxon rank-sum test was used to compare medians between groups of measured and predicted MLwood. Simple modifying factors to account for the significant differences in MLwood groups were developed and the use of which subsequently illustrated. Overall, Podsol soils delivered the highest mean measured MLwood, while Braunerde soils the lowest. Braunerde in “M” was the only group to not register a significant difference between measured and predicted MLwood groups. Soil temperature and moisture conditions still played a dominant role in the resulting wood decay, however the need for a variable describing an additional soil property was shown. The study suggests further investigation into the development of modifying factors for different soil types, where the effect of moisture- and temperature-induced components alone cannot reliably predict wood decay in soils differing from a reference, like those used in laboratory-based TMC studies.
B N Marais, S Kovacs, M Jansen, C Brischke


Comparative response of Reticulitermes flavipes and Coptotermes formosanus to borate soil treatments
1991 - IRG/WP 1486
Eastern (Reticulitermes flavipes [Kollarl]) and Formosan (Coptotermes formosanus Shiraki) subterranean termite workers (Isoptera: Rhinotermitidae) were exposed to borate-treated sand in an indirect exposure tunneling assay in the laboratory. In the ten day assay period, both termite species readily penetrated sand containing 5000, 10000, or 15000 ppm (wt. of compound / wt. of sand) disodium octaborate tetrahydrate (Tim-BorÒ) or zinc borate (Firebrake ZB-FineÒ). With Reticulitermes flavipes, significant mortality (85-93%) resulted from workers tunneling through sand treated with 5000 ppm disodium octaborate tetrahydrate (higher concentrations were also effective), or 15000 ppm zinc borate. Responses of Coptotermes formosanus workers were lesser and more variable, with only concentrations of 10000 and 15000 ppm zinc borate resulting in mortality 70-89%) significantly different from that in the control groups. These results suggest that differences between these two species in tunneling behavior may reduce exposure of Coptotermes formosanus to the borate-treated sand.
J K Grace


The effect of certain wood extractives on the growth of marine micro-organisms
1977 - IRG/WP 438
S E J Furtado, E B G Jones, J D Bultman


Response of the Formosan Subterranean Termite (Coptotermes formosanus) to Cellulose Insulation Treated with Boric Acid in Choice and No-Choice Tests.
2004 - IRG/WP 04-10532
The tunneling ability of the Formosan subterranean termite Coptotermes formosanus Shiraki through a cellulose insulation material containing11.1% boric acid was tested in choice and no-choice bioassays. We examined tunneling behavior and mortality of termites exposed to treated and untreated insulation material in miniature simulated wall voids. In a choice test termites tunneled through untreated insulation in all but one of the replicates used. Termites were unable to fully penetrate any of the replicates containing treated insulation and experienced a significantly higher mortality (78.4 ± 18.4%) than termites exposed to untreated insulation (11.6 ± 5.6%, F = 60.4, df = 1, P < 0.0001). In a no- choice test termites fully penetrated all replicates containing untreated insulation and experienced 37.1 ± 37.2% mortality. Termites exposed to treated insulation in this test experienced a significantly higher mortality of 100.0% (F = 14.3, df = 1, P < 0.005), and did not fully penetrate the treated insulation.
M E Mankowski, J K Grace


Response of laboratory groups of Reticulitermes speratus (Kolbe) to different quantities of food
2003 - IRG/WP 03-10489
As part of a project aimed at improving understanding of the foraging biology of Japan’s most widespread wood-destroying termite, different sized groups of Reticulitermes speratus (0.5; 1 and 2 g) from two colonies were kept on 16 or 64 cm3 of sapwood of Cryptomeria japonica for 12 weeks in the laboratory. Patterns of wood consumption, wood consumption rates and survival are discussed.
M Lenz, T Yoshimura, K Tsunoda


Preservative absorption response of planks of Anogeissus acuminata for plank-built catamarans
2002 - IRG/WP 02-40245
Due to shortage of timber coupled with other compelling factors, traditional fishermen along the east coast of India, especially of Andhra Pradesh, of late, are departing from conventional log type wooden catamarans. Instead, they are fabricating catamarans out of timber planks of hard woods and utilizing thermocol for buoyancy. Mostly, locally available timber of a Combretaceae species, Anogeissus acuminata (Yon) is used to fabricate these plank-built catamarans. Since these catamarans are also built with untreated timber, there is every need to extend wood preservation technology to these craft also so as to achieve enhanced service life and conserve the resources. Therefore, the Institute of Wood Science and Technology took up treatment of timber meant for five such craft with copper-chrome-arsenic (CCA). Thirteen different logs were procured and converted into planks and batons of suitable sizes, debarked, cleaned and air dried under shade. While the length of the planks ranged from 0.81 to 6.53 m, the width varied from 16 to 44 cm. After sufficient seasoning, the material was pressure treated with 6% CCA by full cell method as per IS: 401 (1982). Chemical retentions were computed from the weight gained by the individual planks and sets of 20 batons immediately after treatment. The preservative absorption in the planks ranged from 13.05 to 69.80 kg/m3 averaging at 25.90 kg/m3 and that in the batons averaged at 32 kg/m3. The quantity of CCA absorbed by the planks was analyzed with reference to their length, width, thickness and volume. Planks when categorized to different length and volume groups exhibited clear difference in the intake of chemical by them but when categorized into different width and thickness classes showed not much variation. All the treated planks and batons after air drying in shade for 15 days were fabricated into five catamarans. Thus, though the planks of A. acuminata are either very long or very wide, they showed a positive response to CCA treatment by absorbing reasonably good quantities of preservative. Similarly, on fabrication of the catamarans, an average retention of 21.79 to 25.43 kg/m3 of CCA per craft could be achieved. These values fall into the recommended preservative absorption range of 16 to 32 kg/m3 (IS: 401, 1982) for marine structures.
V Kuppusamy, M V Rao, M Balaji, K Rao


Methods for testing fumigant efficacies against termites
1986 - IRG/WP 1297
Methodologies for testing fumigants against termites are reviewed and factors needed to be taken under consideration for standardization listed. Toxicity should be defined by both direct exposure to the gas and under more practical "barrier" conditions which include test enclosures simulating abiotic surroundings of the termites, i.e. wood, nest material, etc. To observe latent effects, mortality should be recorded periodically after exposure until rates decrease to control levels. Fumigant efficacy should be reported as a function of concentration and exposure time, termed lethal accumulated dose (LAD).
N-Y Su, R H Scheffrahn


Positive dosage response of CCA in hardwood power poles to soft rot indicated from New South Wales soft rot survey dat
1983 - IRG/WP 3233
Experience and observation have shown that retentions of less than 16 kg/m³ in the sapwood of individual hardwood poles are unlikely to delay its deterioration sufficiently to ensure an economic performance in some instances. The higher retentions of current practice should do so subject to adequate inspection and maintenance. Increases in retentions requirements up to 35 kg/m³ more or less, depending on species should now be implemented in the interest of securing a greater margin of confidence in the product at small additional cost.
A J Witheridge


Physiologic response of Phanerochaete chrysosporium to exposure to triazole fungicides
1994 - IRG/WP 94-10066
Triazoles are increasingly important fungicides which are employed for a variety of applications included wood protection. Several recent studies suggest that white rot fungi are more tolerant of triazole compounds than other wood degrading fungi. Cultural studies using a white rot fungus, Phanerochaete chrysosporium, and 0.2 or 0.8 ppm of tebuconazole or propiconazole suggested that mycelial dry weight was most affected by the presence of triazoles. Extracellular carboxymethylcellulase, cellobiosidase and phenol oxidase activities were depressed but not inhibited by triazoles, while ß-glucosidase activity appeared to be slimulated by the presence of these biocides. The results suggest that white rot fungi may be less sensitive to triazoles and this diminished sensitivity may permit these fungi to become more important on wood treated with this biocide.
J J Morrell, R K Velicheti


Termite Response to Agricultural Fiber Composites: Hemp
2005 - IRG/WP 05-10548
Industrial hemp, Cannabis sativa, is a fiber usable in manufacture of nutritional products, rope, textiles, paper and building products. Due to the illicit recreational uses of Cannabis sativa varieties with high tetrahydrocannabinol content (marijuana), hemp is not grown commercially in the United States. However, it is grown in many other nations, and has been proposed as a replacement for sugarcane and other commodity crops in the United States, including Hawaii. These studies were undertaken to determine the susceptibility of several potential hemp building products to Formosan subterranean termite attack. Although advocates of the fiber sometimes comment on its relative resistance to insects and decay fungi, there is little to no data available to either substantiate or refute these claims. Termite responses to experimental hemp fibreboards (UF or MDI resins), and to a commercial mineralized hemp building material (Isochanvre) were evaluated in laboratory essays. The hemp fibreboards were readily attacked by termites, although the UF resin was relatively toxic to them in comparison to MDI. Termites also readily consumed the mineralized hemp fibers, although mortality was high. Thus, one can conclude that hemp is susceptible to termite attack. Urea formaldehyde resin in fibreboards and silica, lime or boric acid in mineralized hemp were detrimental to termite survival, but still did not prevent significant attack. Preservative or other treatments appear to be required to protect hemp building products from degradation.
J K Grace


Termite response to Agricultural Fiber Composites: Bagasse
2005 - IRG/WP 05-10549
Bagasse, or sugarcane rind, is a fibrous by-product of sugar extraction from sugarcane, Saccharum officinarum L. Bagasse fiber performs similarly to hardwood fiber in composite board products. In laboratory studies, Formosan subterranean termites survived as well on a diet of Bagasse as on Douglas-fir wood. Field tests with a compressed Bagasse panel (produced by heat extrusion) indicated that termites readily penetrated the acrylic/vinyl latex coating on the panel, and tunnelled throughout the interior Bagasse fibers. Treatment of the fibers with disodium octaborate tetrahydrate did not prevent the termite penetration of the panel exterior. Subsequent moisture sorption by the fibers led to rapid swelling and deformation of the panels. A dimensionally stable, high density Bagasse particleboard was also evaluated in laboratory tests. No swelling was noted, although the particleboard was readily penetrated and consumed by Formosan subterranean termites, and mold growth was also noted on the test wafers. In recent years, high-profile Bagasse board production facilities were opened in both Louisiana and Hawaii, only to close shortly thereafter. Bagasse may have more market potential in a value-added, preservative treated product than as a low-end commodity competing with comparable wood products.
J K Grace


Risk of pulmonary damage as a result of an evaporation of ca. 50 ppb = 42 mg HF, evaporated from wood treated by difluorides
1987 - IRG/WP 3401
In this review of the literature the effects of fluorides and fluorine on man are described, especially the low level effects of inhaled HF on human beings. The term "fluoride" is used as a general term everywhere, where exact differentiation between ionic and moluecular forms or between gaseous and particulate forms is uncertain or unnecessary. The term covers all combined forms of the element, regardless of chemical form, unless there is a specific reason to stress the gaseous elemental form F2, in which case the term "fluorine" is used.
H F M Nijman


Unsuitability of the limiting dose as a criterion for assessing the toxicity of preservatives to wood-destroying fungi
1974 - IRG/WP 243
In the majority of methods for investigating preservatives for wood-destroying fungi their toxicity is assessed by determining what is called the "limiting dose". This normally denotes a range of preservative solution concentrations or retentions of dry preservative in the timber, the lower value serving to indicate the amount of preservative at which is observed the expected effect, e.g. the growth of fungus round the timber or the destruction of the timber by the fungus, while the higher value is regarded as the minimum amount of preservative at which the expected effect is not observed. The limiting dose is regarded as a criterion for assessing the toxicity of the preservative and is used when comparing different preservatives for toxicity to a particular species of fungus, and also for characterizing the sensitivity of the different species and strains of fungi to the particular kind of preservative.
D A Belenkov


Respiratory response of the wood boring teredinid, Lyrodus pedicellatus (Quatrefages) to copper stress
2004 - IRG/WP 04-10528
Wood boring teredinid molluscs engulf most of the wooden particles scrapped by them while actively boring into wood, obtaining nourishment for their metabolic activities. In order to protect the wooden structures from the biodeteriorating activity of such organisms, the wood is treated with different chemical formulations to prolong their service life. Copper chrome arsenic (CCA) is one such wood preservative chemical offering excellent protection to wood under marine conditions. Field observations with CCA treated test stakes as well as actual wooden structures have, however, shown that they are not free from wood borer attack after considerable service life. The successful settlement and growth of these organisms are a reflection of their metabolic ability under such adverse chemical stress conditions. As copper and arsenic are known to be metabolic inhibitors, a study was undertaken to investigate the respiratory behaviour of Lyrodus pedicellatus (Quatrefages), the most virulent teredinid wood borer at Visakhapatnam harbour, East Coast of India. As a first step, experiments were conducted on this aspect under copper stress. The results show that in situ oxygen consumption of the animal under normal conditions was found to range from 0.8 – 5.6 &#956;l.mg-1.hr-1 averaging 2.43 &#956;l.mg-1.hr-1. Under acute toxicity of 0.5 ppm copper, the oxygen demand was observed to fall almost to half the normal levels (0.4 – 3.5 &#956;l.mg-1.hr-1), but showed a gradual increase subsequently during the next 24 hours. However, when the stress was continued for 96 hours, the oxygen uptake gradually decreased again to 0.2 – 2.1 &#956;l.mg-1. hr-1.
V Kuppusamy, M Balaji, M V Rao, K S Rao


An example of media response to perceived environmental problems with CCA-treated wood
1990 - IRG/WP 3564
A recent study suggested that CCA-treated wood exposed to acidic precipitation could lose significant amounts of copper chromium and arsenic resulting in loss of efficacy and possible environmental contamination. The study received wide newspaper and radio coverage in Canada, thereby heightening public concern about CCA use. Subsequent studies in our laboratory confirmed that the high losses were caused by a citric acid buffer used to stabilize pH in the origional study. It is hoped that this "case study" will stimulate discussion and thoughts on how this type of situation should be addressed by scientists others involved with treated wood.
P A Cooper


Dutch national environmental policy strategy (NMP): Implications throughout the life cycle of treated timber and for the Dutch preservation industry
1993 - IRG/WP 93-50001-31
All overview of relevant environmental legislation and instruments for control is given for each stage of the life cycle of treated timber. Recent policy in the Netherlands has been focused around the "National Environmental Policy Strategy", in which a general policy with regard to reduction of pollution to the air, soil and water is described. The principle is one of an "Integrated Chain of Control" and reduction of emissions at the source of pollution. This means all aspects of pollution should be inventorised throughout the life cycle of a product, from source and manufacture to the waste stage. For treated timber this life cycle is: the wood preservative, the treatment (impregnation plants, storage), treated timber in service, treated timber as waste. As a country rich in water, in the Netherlands much emphasis is given to the reduction of emissions from treated timber to water, either during storage, or during service life. The reality thet treatment plants in the Netherlands face with regard to regulatory bodies (Waterboards, Municipalities) are highlighted. The response of the Dutch wood preservation industry in complying with existing and possible future regulations is described.
P Esser, D A Lewis, A J Pendlebury


Characterization of Poria indoor brown-rot fungi
1995 - IRG/WP 95-10094
The heterogeneous group of "Poria" fungi causing brown rot in buildings and also of wood in ground contact comprises Antrodia vaillantii, Antrodia serialis, Antrodia sinuosa, Antrodia xantha and Tyromyces placenta. These fungi have similar morphological appearance and biology. Their nomenclature has a confusing history and is still not uniform. As a consequence, misinterpretations may occur. SDS polyacrylamide gel electrophoresis showed a species-specific protein pattern for different cultures of Antrodia vaillantii separating the species from the other pore fungi as well as from Coniophora puteana and Serpula lacrymans. Electrophoresis also detected misidentifications. Investigations on growth rate, response to temperature, copper tolerance and wood decay revealed: Radial growth extension reached from 4 to 9 mm/d. Temperature optimum was 25 to 31°C. All withstood 1 hour at 60°C and some even 3 h at 65°C. Antrodia vaillantii was copper tolerant up to 0.05 M Cu. Wood weight loss after 20 weeks was higher by Tyromyces placenta (35%) and Antrodia sinuosa (33%) than by Antrodia xantha (21%), Antrodia serialis (16%) and Antrodia vaillantii (14%). Dual cultures revealed various inter- and intraspecific interactions and detected identity of differently coded cultures of a species. The former Poria vaporaria sensu Liese &apos;Normstamm II&apos; for testing wood preservatives and the recent Poria placenta EN 113 strain FPRL 280 were shown to be either identical or at least sister monokaryons originating from the same individual.
O Schmidt


Chemostimulatory and chemotropic responses by fungi to preserved and unpreserved wood
1981 - IRG/WP 1134
During experiments to determine the presence of biotic connections between soil and wood at this laboratory, marked chemotropic responses to wood were demonstrated by some wood destroying micro-organism in agar culture. These were shown at some distance from bait, up to 35 mm away, and on some occasions were unaffected by the presence of toxic materials. This paper provides preliminary data on the chemostimulation of wood destroying organisms by preserved and unpreserved wood.
G Mowe, B King


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