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Fungal decay resistance and mechanical properties of plywood panels made from maritime pine (Pinus pinaster) and bonded with cornstarch-quebracho tannin-phenol formaldehyde adhesive
2010 - IRG/WP 10-40490
The aim of this work is to demonstrate the performances of cornstarch-quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol-formaldehyde (PF). In order to evaluate the mechanical performances of optimal cornstarch-quebracho tannin-PF, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The biological performance of plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi were evaluated. The performance of these panels is comparable to those of plywood panels commercial PF made. The results showed that plywood panels bonded with cornstarch-quebracho tannin-PF resins (15:5:80, w:w:w) exhibited better mechanical properties than plywood panels commercial PF made. The formaldehyde emission levels obtained from panels bonded with cornstarch-quebracho tannin-PF were lower to those obtained from panels bonded with control PF. Biodegradation studies show that the presence of quebracho tannin in the adhesive improves the total resistance of the plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi.
F Charrier, A Moubarik, A Allal, A Pizzi, B Charrier


Fungal decay resistance and durability of wood products made from borax-impregnated wood and bonded with corn starch and tannin adhesive
2009 - IRG/WP 09-30494
At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol formaldehyde (PF) resins and urea formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply. This paper concerns the decay resistance of wood products bonded with a new, environment-friendly adhesive derived from abundant and renewable cornstarch and tannin.To improve the total resistance of the composite against both Coriolus versicolor and Coniophora puteana rots fungi, borax (di-sodium tetraborate) was added in proportions of 0.5%, 1% and 2% (w/w) to the cornstarch-tannin adhesives. The results showed that increasing the concentration of borax in the adhesive decreased the mechanical properties of the composite. The best way to avoid this problem was to use wood impregnated with borax. Biodegradation studies were conduced on new composites, first without any treatment, followed by borax at 0.5 % aqueous solution treatment. The results show that wood impregnated with borax, in presence of tannin and sodium hydroxide in the adhesive improves the total resistance of the wood composite against both Coriolus versicolor and Coniophora puteana rot fungi.
A Moubarik, A Pizzi, A Allal, F Charrier, B Charrier


Biological and mechanical performances of particleboard panels made from maritime pine (Pinus pinaster) and glued with cornstarch-mimosa tannin-urea formaldehyde adhesive
2011 - IRG/WP 11-40542
The objective of this work was to demonstrate the utility of cornstarch-mimosa tannin-based resins designed for application as an adhesive in the particleboard production. Bond qualities of cornstarch-mimosa tannin- urea formaldehyde (UF) (10:4:86, weight ratios) resins and commercial UF resin were assessed by using an automatic bonding evaluation system, prior to production of particleboard panels. In order to evaluate the quality of cornstarch-mimosa tannin-UF (10:4:86, weight ratios) resins, particleboards were produced and physical and mechanical properties were investigated. These physical properties included rheological and solid phase 13C NMR analysis of resins. The biological performance of particleboard panels against both Coriolus versicolor and Coniophora puteana rots fungi were evaluated. Internal bond, surface soundness, modules of rupture and modulus of elasticity mechanical properties of particleboards bonded with cornstarch-mimosa tannin-UF (10:4:86, weight ratios) resins were also determined. The results showed that it is possible to add cornstarch and mimosa tannin respectively up to 10 % and 4 % to the UF resin without to alter the physical and mechanical properties of the boards. The performance of these panels is comparable to those of boards made using commercial UF resin. Biodegradation studies show that the presence of mimosa tannin in the adhesive improves the total resistance of the particleboards panels against both Coriolus versicolor and Coniophora puteana rot fungi.
A Moubarik, F Charrier, A Pizzi, A Allal, B Charrier


Improvement of wood decay resistance by tannin impregnation
1991 - IRG/WP 2380
The fungical effect of tannins is appraised after exposure of treated woods samples to wood rotting fungi. A screening-test is carried out with several solutions containing extracts of two kinds of tannins; a condensed tannin derived from Quebracho heartwood (Schinopsis sp.) and a hydrolyzable one extracted from chestnut heartwood (Castanea sativa Mill). If a fungicidal action was indeed found it is not sufficient to offer an alternative to classical chemical preservatives. However, it will be interesting in the future, to use their ability to form insoluble complexes with metal ions to fix within the wood fungicides like copper otherwise easily leached.
D Dirol, A Scalbert


Decay resistance of beech wood and plywood treated with different type of phenol-formaldehyde (PF) resins
2016 - IRG/WP 16-40717
In this study treatment of beech and poplar wood veneers with (PF) resin industrial scale and screening tests of nine different phenol-formaldehyde (PF) resins were made. Specifically, the effect of different phenol-formaldehyde (PF) resin types on the resistance of beech wood against brown- and white-rot fungi was evaluated. Criteria for selection of optimal (PF) resin were based on minimum WPG requirements to achieve equal durability class (1st durability class according to the EN 350 standard) against fungi. Therefore European beech (Fagus sylvatica) wood blocks (15x20x50 mm³) were vacuum impregnated to various weight percent gains (WPGs) with water-soluble PF resins. Different WPG levels were achieved by using aqueous resin solutions at concentrations of 9, 18 and 27 wt %. Treated wood blocks were exposed to brown-rot fungi (Gloeophyllum trabeum (G.t); Coniophora puteana (C.p)) and white-rot fungi (Trametes versicolor (T.v); Pleurotus ostreatus (P.o)) for 16 weeks. A WPG of approximately 8–14% was necessary for beech wood blocks for a treated with the resin C, D, I and E, but approximately 16% and 27% was necessary when using other resins as B, F, G, H, respectively. Irrespective from resin the required WPG for decay resistance against brown rot fungi was approximately 50-60% lower compared to decay resistance against white rot. No effect of resin on the resistance against (G.t) decay of wood blocks was observed, resulting in resin loadings of 7–8%, whereas the required WPG for (C.p) decay suppression slightly increased from 8 up to 11%, respectively. The results suggest that the magnitude of white fungal deterioration of treated wood is strongly affected by the resin used for treatment. Resin loadings from 7% to 17% against (T.v) and from 12% to 27% against (P.o) were required. This broad range in WPG may be due to varied fungal aggressiveness, filling of the cell wall micropores (bulking) and the stiffness (pliability) of the cell wall matrix. From aforementioned, two resins D and E were selected for treatment of beech and poplar veneers on industrial scale and resistance of treated plywood against white rot fungus (T.v) was evaluated according EN 12038 standard.
V Biziks, S Bicke, H Militz


The decay resistance of chemically modified aspen composites to the white rot fungus Coriolus versicolor (L.) Quelet
1998 - IRG/WP 98-40122
Chemical modification of Aspen wood (Populus tremula L.) in the form of solid wood, veneers and sawdust was undertaken by a two step procedure consisting of esterification with maleic anhydride (MA) and subsequent oligoesterification with MA and glycidyl methacrylate (GMA) or allyl glycidyl ether (AGE). Modified wood was thermoplastic and was thermally formed by hot-pressing to produce veneer or solid wood samples with smooth glossy surfaces, while plastic-like wafers were obtained by hotpressing modified sawdust. Chemical modification alone was shown to enhance the biological resistance of Aspen to decay by Coriolus versicolor. In addition, hot-pressing enhanced decay resistance of both unmodified wood and esterified wood veneer samples, although no improvement was found by hot pressing oligoesterified wood. The most effective treatment for the improvement of decay resistance was chemical modification of the sawdust in conjunction with hot-pressing. A microscopic examination of chemically modified and control samples following exposure to the fungus showed more extensive colonisation and decay in untreated, unpressed samples.
M C Timar, A J Pitman, M D Mihai


Studies on the preservation of structrual plywood - Part 1: Decay resistance of structural plywood
1974 - IRG/WP 238
The weight loss and the decreases in the compression strength and in the modulus of elasticity were measured to determine the decay resistance of structural plywood (lauan). Test pieces (50x25xA mm³) were exposed to the wood destroying fungi (Coriolus versicolor and Coriolellus palustris) for 2-3 or 2-4 months. After exposure, the measurement of the compression strength was carried out on the pieces of different thickness (A = 6,12 and 18 mm) and different fibre direction of the face veneer (0°, 45° and 90° to the long side of the test piece). The results obtained were as follows: 1.: The weight loss was small. The greatest weight loss was 9.4% on decaying by Coriolellus palustris for 4 months. 2.: The decreases in the compression strength and in the modulus of elasticity were greater than the weight loss. On decaying by Coriolellus palustris for 4 months, the ratio of decrease of the compression strength was 75% (6 mm - 0°). 3.: For differences of the thickness and of the fibre direction, the weight loss and the decreases the modulus of elasticity in the compression strength and in the modulus of elasticity showed tendencies in order 0° > 45° > 90° and 6 > 12 > 18 mm. 4.: According to the experiment, the face veneer is liable to be easily attacked by the wood destroying fungi, but the decrease in the compression strength was great. So, the face veneer and the cross section should be protected with preservatives for structural use.
K Minami, Y Kenjo, S Sugiyama


Effects of a formaldehyde and sulphur dioxide treatment on decay and mechanical properties of aspen waferboard
1983 - IRG/WP 3242
Aspen wafers were sequentially treated under vacuum with formaldehyde and sulfur dioxide gas and pressed into waferboard bonded with powdered phenol formaldehyde resin. Decay resistance and strength properties were determined before and after simulated weathering. The water resistance of the phenol bonding system was lost in board made from the gas-treated wafers. This white rot fungus Coriolus versicolor was unable to decay treated waferboard in a soil block test, but the brown rot fungi Gloeophyllum trabeum and Poria placenta decayed the samples as severely as untreated controls.
E L Schmidt


Laboratory determination of the natural decay resistance of some lesser-utilized timbers from Tanzania against wood decay fungi
2004 - IRG/WP 04-10517
Four lesser known/utilized timber species (sap and heartwoods) from Tanzania, namely Albizia lebbeck, Zanthoxylum gilletii, Faurea saligna and Parinari curatellifolia were exposed to the brown rot fungi (Gloeophyllum trabeum and Coniophora puteana) and the white rot fungus (Coriolus versicolor) to determine their natural decay resistance according to the EN 113 standard procedure. The timbers were also ranked into natural durability classes according to EN 350-1. Albizia lebbeck, Faurea saligna and Parinari curatellifolia timber species (heartwood) were found to be very resistant while Zanthoxylum gilletii was heavily decayed by all the fungi. The durability ratings of the timbers were; Albizia lebbeck (1), Faurea saligna (1), Parinari curatellifolia (1) and Zanthoxylum gillettii (5). It is suggested that the durable timbers, Albizia lebbeck, Faurea saligna and Parinari curatellifolia should be promoted as alternatives to the well known durable timber species in Tanzania such as Tectona grandis, Afzelia quanzensis, Blachylaena hutchinsii and Pterocarpus angolensis which are currently being over-exploited.
P R Gillah, R C Ishengoma, E Julias, S A Amartey, D H Kitojo


Effect of Scytalidium lignicola on decay resistance and strength of wood
1994 - IRG/WP 94-10061
We reported previously that in laboratory tests, pretreatment of Douglas-fir and Southern Pine blocks with Scytalidium lignicola prevented decay. In the present work, we determined 1) the ability of Scytalidium lignicola to colonize and survive in wood exposed in the field, 2) the decay resistance of blocks removed from previously treated Scytalidium lignicola wood and 3) the effect of Scytalidium lignicola on strength of wood (modulus of rupture (MOR). After two years exposure in the field, Scytalidium lignicola was still isolated throughout pine log sections. Decay fungi were not isolated from Scytalidium lignicola treated sections but were isolated from untreated controls. Unsterilized blocks removed from the pine sections after one year's exposure in the field were resistant to decay by Coriolus versicolor and Postia Placenta. However, decay prevention was lost when blocks were sterilized. Southern Pine and Douglas-fir timbers (15.2x15.2x30.5 cm³) treated with Scytalidium lignicola were completely colonized by one month. Like the pine sections, unsterilized wood removed from the timbers was decay resistant but resistance was lost with propylene oxide sterilization. MOR of Southern Pine was only slightly reduced after 16 weeks exposure to Scytalidium lignicola over soil.
T L Highley


Preservation of robinia wood (Robinia pseudoacacia L.) stakes by vintners
1982 - IRG/WP 3194
This work discusses decay resistance of robinia wood to fungi Trametes versicolor (L.ex Fr.) Pil. and Coniophora puteana (Schum. ex Fr.) Karst., and also the possibility of influencing its resistance by means of chemical protection. The results showed that natural resistance of robinia wood to these two different agents of wood decay is not the same. It is much less resistant to the fungus Coniophora puteana (Schum. ex Fr.) Karst. than to the fungus Trametes versicolor (L. ex Fr.) Pil. Under certain conditions resistance and, consequently, durability of robinia wood can be increased, if it is impregnated with a chemical using the basis of copper-napthenate.
R Benko


Decay resistance of Platanus acerifolia wood against White Rot Fungi (Coriolus versicolor)
2002 - IRG/WP 02-10431
Degradation of the lignocellulose complex in wood varies on the microorganism causing decay and chemical composition of wood. The weight loss of Platanus acerifolia wood after decay by white rot fungus (Coriolus versicolor) for period 16 weeks were evaluated according to European standard EN 113 and beech wood as a control. The samples were collected in October 2000 from Nantes, France. The aim of this work was to test the degradation of Platanus acerifolia versus transverse section of tree. Our results also demonstrate a gradual mass loss from heartwood to sapwood and suggest a quantitative relationship between mass loss and chemical composition of transverse section of Platanus acerifolia.
M Irmouli, O Duchelier, N Ayadi, B Charrier


The resistance of wood coated with different water-borne paints against colonisation by decay fungi
1996 - IRG/WP 96-10165
The susceptibility of wood painted with model paints of known composition to decay fungi was tested without previous weathering. Included in the study were five alkyd emulsion paints and five acrylic paints; one linseed oil paint and two solvent-borne alkyd paints. It was found that several components influenced the susceptibility of these paints. The results of the present study indicate that the particle size of latex paints, the pigment volume concentration and the amount and type of surfactant in the water-borne paints are critical for colonisation by decay fungi of painted wood. An anion surfactant was somewhat fungicidal. The results are briefly discussed in relation to major paint components and to available knowledge of the properties of water-borne coatings on wooden substrates. The present study is part of a larger project aiming at improvement of the durability of painted wood.
J Bjurman


Leaching performance, decay and termite resistance of wood treated with boron compounds incorporated with phenol-formaldehyde resin
2009 - IRG/WP 09-30503
A resol-type phenol-formaldehyde (PF) resin was synthesized and designed to penetrate wood incorporated with boron compounds in order to immobilize boron in wood. The leaching performance, decay and termite resistance of treated wood was investigated. Three kinds of boron compounds, that is, boric acid (BA), borax (BX) and disodium octaborate tetrahydrate (DOT), were selected to mix with PF and two species of wood (Chinese fir and Masson pine) were selected as the treating samples. The leaching process of boron from wood blocks was performed according to the American Wood Preservation Association (AWPA) standard E11-06. And the boron content in treated wood and leachates were determined by inductively coupled plasma optical emission spectrometer (ICP-OES). The results showed that boron leaching was reduced markedly and negligible boron was leached in some treatments. In laboratory termite tests against Coptotermes formosanus Shiraki, treated wood showed low weight loss. In addition, in laboratory decay test using a brown-rot fungus (Gloeophyllum trabeum) revealed that the decay resistance of PF-boron treated wood was also greatly improved.
Liping Yu, Jinzhen Cao


Decay Resistance of Maple (Acer Insigne) Wood Against White Rot
2010 - IRG/WP 10-10740
In this study, the decay resistance of maple (Acer insigne) in natural state and treated with ACC (Acid copper chromate) was investigated against the white rot fungus (Coriolus versicolor). ACC is a kind of water borne preservatives that was used in this study for treating specimens under vacuum and pressure (Bethell procedure) with 3 percent concentration. In conducting mentioned evaluation, kolleschale’s method according to DIN 52176 and B.S. 838: 1961 were used in completely randomized block design. Specimens were contaminated with cultured fungus for fourteen weeks in condition (22, 75% relative humidity). After this period, weight reduction, compressive strength (parallel to grain) and hardness of specimens were tested. Under test conditions weight reduction of control sample were much higher than treated ones. Compressive strength (parallel to grain) and hardness of treated samples were higher than control ones.
V Tazakor Rezaei


Coconut lumber for wood decks (Cocos nucifera L.): decay resistance against Basidiomycetes fungi
2012 - IRG/WP 12-10784
Since a couple of years, manufactured products of coconut wood for outdoor uses like wood decks have been proposed on the European market. These are presented as an alternative for traditional tropical timbers. In the past, coconut wood was neglected and burned for sanitary reasons and lack of interest at industrial scale. Plantation coconut trees at end of production of copra constitute a renewable resource with high added value. In order to convince the markets, natural durability for outdoor use, without preservative treatment, against wood destroying fungi characteristic of northern temperate regions is a major property that has to be checked. Natural durability of coconut lumber was tested in the laboratory according to the European standard EN 15083-1 against brown (Coniophora puteana) and white (Coriolus versicolor) rot decay basidiomycetes fungi. Beech wood specimens were used as virulence controls. Mass losses were determined after 16 weeks exposure. The results showed that tested coconut wood is very resistant to the brown rot fungus Coniophora puteana and resistant to the white rot fungus Coriolus versicolor. Mass loss and density of tested samples with C. versicolor are inversely related. In addition, the density shows a large variability in the test sample, more than 500 kg / m³. These results confirm that after a selection on density criteria, the natural durability of Coconut lumber is sufficient for outdoor application in use class 3 (based on European standard EN 335 and in line with EN 460).
B Jourez, C Verheyen, J Van Acker


Effect of Nano-silver and Nano-copper and Nano-zinc oxide on Paulownia wood exposed to white-rot fungus
2013 - IRG/WP 13-30635
Paulownia is known as a fast growing tree and it can be used in several applications. The present study investigated the effect of Nano-silver and Nano-copper and Nano- zinc oxide on resistance of Paulowina (Paulownia fortunei) wood against the white rot fungus (Coriolus versicolor). Wood specimens with a dry density of 0.37g/cm3 were impregnated with a 400 ppm aqueous suspension of micronized nano-silver and nano-copper with particle sizes ranging from 10 to 80 nm , in a pressure vessel at 2.5 bars for 20 minutes. Treated specimens were inoculated with the fungus and incubated for sixteen weeks at 26˚C with 65% relative humidity in accordance with the EN113 standard. After incubation the mean percentage weight losses of specimens were measured. Percentage weight loss of control samples was much higher than treated ones. Results of the analysis of variance showed that the impregnation of wood with nanosilver, nanocopper and nanozinc oxide significantly increases the decay resistance of Paulownia against this white rot fungus.
M Akhtari, M Ganjipour


Successive collections of Basidiospores from wood decay fungi (in vitro) show variation in germination levels on common media
1978 - IRG/WP 191
In the course of various preliminary experiments in which spore germination levels of 6 decay fungi on malt and water agar were recorded as controls, it was noted that one could not reliably obtain an expected level of spore germination for any particular fungus. Inconsistent 'control' spore germination levels of a fungus greatly complicates large scale experiments in which comparisons of data based on germination levels are attempted upon replication of the study over time. This study was done to determine if, in fact, spores collected at different times from specific hymenial areas of wood decay fungi sporulating in vitro differed significantly in germination level on common media under standardized conditions.
E L Schmidt, D W French


The leachability, biological resistance, and mechanical properties of wood (Pinus sylvestris L.) treated with CCA and CCB preservatives
1999 - IRG/WP 99-30207
Scots pine (Pinus sylvestris L.) specimens treated with CCA and CCB preservative solutions (1.0%) were subjected to several fixation processes and leached elements from the specimens were determined. In addition, the specimens exposed to different fixation temperatures were subjected to soil-block test using two brown-rot fungi and one white-rot fungus in order to investigate the effects of fixation temperature on the biological performance of treated wood. The effects of preservative treatment and subsequent redrying at temperatures of 20°C and 70°C on the bending strength, MOE (modulus of elasticity), and impact bending strength of small, clear specimens treated with CCA. At 20°C and high moisture contents and also with steaming, leaching rate of the components decreased. In addition, the specimens treated with CCB and conditioned at 20°C/32-100% RH (relative humidity) conditions, the percent elements leached were less than those in the specimens treated with CCA and also the rate of fixation increased significantly in the CCB-treated specimens. In the CCA treatments, the weight losses by Gloeophyllum trabeum and Postia placenta fungi were more than 5% with the fixation methods such as ovendrying at 120°C, and steaming at 80°C for 60 and 90 minutes while with the other fixation methods, the weight losses obtained were less than 5%. At redrying temperatures of 20 and 70°C, CCA had no significant negative effect on the bending strength, MOE, and impact bending strength properties of the specimens.
S N Kartal


Combined effects of the treatment of wood with formaldehyde
1978 - IRG/WP 3117
Treatment of fibrous materials with reagents in a vapor phase is neither new nor unique. Numerous examples exist in literature of vapor phase experiments on cellulose fibers and fabrics, and on wood. For many years the textile research and industry have used vapor phase processes for the treatment of textiles. The chemical modification of cellulose is based on different types of reactions e.g. esterification, alkylation, resin formation or polymerization, monomer grafting and crosslinking. Vapor phase treatment of wood offers certain potential advantages over the conventional liquid phase wood impregnation. The higher mobility of low molecular weight compounds in the gaseous state ensures a rapid, uniform and homogeneous distribution throughout the wood structure. The vapor phase treatment of wood is also a better approach from the standpoint of cell wall penetration. Bulking, which takes place in the cell wall only, means that less chemicals are required and that the final weight of the composite is limited. Furthermore, due to the low viscosity of a gas, the application of a lower pressure differential remains possible. Within the framework of a wood improvement programme carried out at the Laboratory of Wood Biology and Wood Technology (University of Ghent, Belgium) the treatments were based on the impregnation of wood with liquid synthetic monomers and with gaseous formaldehyde. The results of the hygroscopic and dimensional behaviour of the wood-plastic-combinations have been published previously. Other papers deal with the physical and chemical interactions between the synthetic products and the natural polymers of the cell wall. This contribution will be restricted to the treatment of wood with formaldehyde in the gaseous state.
M Stevens, J Schalck


Involvement of hydrogen peroxide in wood decay by brown-rot and white-rot fungi
1985 - IRG/WP 1256
To gain further understanding of the role of H2O2 in wood degradation by brown- and white-rot fungi, we studied the following: (a) extracellular H2O2 production, (b) effect of various hydroxyl radical (·OH) and singlet O2 (1O2) quenching agents on wood and cellulose degradation, (c) intracellular H2O2 production and catalase activity, and (d) cytochemical localization of H2O2 with diaminobenzidine (DAB) during wood degradation. Extracellular H2O2 detection varied with the growth media and chromogen. The chromogen 2,2'-azino-di-(3-ethyl benzthiazoline-6-sulphonic acid) (ABTS) was more sensitive than o-dianisidine. Extracellular H2O2 was not detected in half of the brown-rot fungi. One white-rot fungus did not produce detectable amounts of H2O2. ·OH and 1O2 quenching agents generally did not inhibit decay of wood or decomposition of cellulose by either brown- or white-rot fungi. DAB did not detect the presence of H2O2 within or outside cells of the brown-rot fungus, Poria placenta. Nor was H2O2 -generating activity detected in sonicated extracts of this fungus. With the white-rot fungus, Coriolus versicolor, H2O2 occurred predominantly in the periplasmic space, but also in the cytoplasm and hyphal sheath. Sonicates of Coriolus versicolor contained H2O2 -generating activity. These observations provide further support for H2O2 involvement in degradation of wood by white-rot fungi, but raise doubts concerning its participation in wood degradation by brown-rot fungi.
T L Highley, L L Murmanis


Biological resistance of phenol-resin treated wood
1990 - IRG/WP 3602
Biological resistance of PF (phenol formaldehyde resin) - treated wood has been tested in relation to the resin properties, wood species and biological factors. When tested using water-soluble PF (mol. wt. 170), ca. 10% RI (resin impregnation) was enough to suppress the decay of Japanese cedar (Cryptomeria japonica) and western hemlock (Tsuga heterophylla) blocks exposed to Tyromyces palustris (brown-rot type) and Coriolus versicolor (white-rot type). For a decay suppression of Japanese beech (Fagus crenata) by treating with the same PF, ca. 20% RI was required for both cases of exposure. When using ethanol-soluble PF (mol. wt. 300), the lesser effect on decay suppression was revealed for most of wood-fungus combinations, suggesting a possible better penetration of lower molecular resin into the wood cell walls. PF treatment of wood also affected the termite Coptotermes formosanus, causing the severe depletion of feeding activity and the higher mortality at 5-15 (%) RI. Of the three species of symbiotic protozoa, the most cellulolytic Pseudotrichonympha grassii diminished first shortly after feeding.
M Takahashi, Y Imamura


Durability of surface preserved wood particle boards submitted to atmospherical influence
1995 - IRG/WP 95-40039
The worldwide problem of the continuously growing deficit of high quality natural wood material has caused the attempts of many research workers to find effective composites such as wood particle boards (WPBs) for replacing the massive wood for constructive purposes, depending on where the boards are exploited - in the open or under a shed, they are submitted to various climatic factors such as heating, drying, moistening, frosting, irradiation, that's why for reaching high atmospheric resistance, it is very important, a durable protection of the WPBs with suitable coatings against the atmospheric influence to be ensured.
L Valcheva


Natural decay resistance of some lesser-used tropical hardwoods from Ghana
2002 - IRG/WP 02-10438
Ghana is a tropical African country that is rich in diverse timber species. In order to reduce over-exploitation of the popular timber species and increase the resource base for the wood industry, lesser-used or lesser-known timber species are being promoted locally and for export. To do this successfully, it is essential to determine the physical, mechanical and biological properties of these timber species in order to determine their commercial potential. Natural decay resistance (natural durability) lesser-used tropical hardwoods from Ghana to the wood decay basidiomycetes (Gloeophyllum trabeum, Coniophora puteana and Coriolus versicolor) were determined according to EN 113 (1980). Fagus sylvatica (beech) was used as a reference timber. Based on mean weight losses (%), the timber species were ranked in order of decay resistance to G. trabeum as: Albizia ferruginea Benth. > Petersianthus macrocarpus Macbride > Amphimas pterocarpoides Harms. > Celtis zenkeri Engl. > Albizia zygia Macbride > Anopyxis klaineana Pierre Eng. > Antrocaryon micraster A. Chev.> Celtis mildbraedii Eng; to C. puteana as: Albizia ferruginea > Amphimas pterocarpoides > Petersianthus macrocarpus > Albizia zygia > Anopyxis klaineana > Antrocaryon micraster > Celtis mildbraedii > Celtis zenkeri and to C. versicolor as: Albizia ferruginea > Anopyxis klaineana > Amphimas pterocarpoides > Albizia zygia > Petersianthus macrocarpus > Antrocaryon micraster > Celtis zenkeri > Celtis mildbraedii. Natural durability ratings for the timbers in accordance with EN 350-1 (1993), were: Albizia ferruginea 1 (very durable), Albizia zygia 3 (moderately durable), Amphimas pterocarpoides 3 (moderately durable), Anopyxis klaineana 3 (moderately durable), Petersianthus macrocarpus 4 (slightly durable), Celtis. mildbraedii 5 (not durable), Celtis zenkeri 5 (not durable), and Antrocaryon micraster 5 (not durable).
S A Amartey, F R Hanson


In vitro sporulation of selected wood decay fungi
1978 - IRG/WP 190
Basidiospores produced axenically without laborious attention in the laboratory are useful in studies of wood decay initiation. Such spores presumably approach those collected from natural sporophores in size and germinability (Morton, 1964). Production of spores in vitro by inversion of cultures grown on 2% malt extract agar in deep glass dishes (100x80 mm²) has been the preferred method (Morton and French, 1966; Toole, 1971). However, for many decay fungi desired as test organisms, spore production is capricious at best, and variation in onset and duration of sporulation frustrates carefully planned experiments. In an effort to improve reliability of this fast: and simple method of spore production, two approaches to minimize the change in nuclear and/or cytoplasmic factors presumed responsible for loss of sporulation were tried. First, freeze-drying of cultures and success of subculturing was investigated. Secondly, a direct subculture method from sporulating 'donor' cultures was used which attempted to transfer enough diversity within mycelial types to increase the number of replicates sporulating.
E L Schmidt, D W French


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