Testing and evaluation of natural durability of wood in above ground conditions in Europe: An overview

• Published in: Journal of wood science 2005-10, Vol.51 (5), p.429-440
• Main Authors: Raberg, U.(Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)), Edlund, M.L, Terziev, N, Land, C.J
• Format: Article
• Language: English
• Subjects: Acoustic tests; BIODETERIORATION; BIODETERIORO; CARIE DU BOIS; CONSERVACION DE LA MADERA; Decay; decay fungi; dry-rot fungus; Durability; ENSAYO; enzymatic amplification; EUROPA; EUROPE; EVALUACION; EVALUATION; Field study; Field tests; Fungi; identification; Identification methods; Laboratories; Laboratory tests; Moisture content; Nondestructive testing; Nucleotides; PCR; Polymerase chain reaction; PRESERVATION DU BOIS; PRODUCTOS DE LA MADERA; PRODUIT DERIVE DU BOIS; PROPIEDADES DE LA MADERA; PROPRIETE DU BOIS; PUDRICION DE LA MADERA; rapd analysis; Relative humidity; ribosomal dna; serpula-lacrymans; strength; t-rflp; TESTAGE; TESTING; Ultrasonic testing; untreated wood; WOOD DECAY; WOOD PRESERVATION; WOOD PRODUCTS; WOOD PROPERTIES; wood testing
• ISSN: 1435-0211; 1611-4663; 1611-4663
• DOI: 10.1007/s10086-005-0717-8

Natural durability of wood is determined by the European standard EN 252 for specimens in ground contact and EN 113 for basidiomycetes in the laboratory, but no test exists for above ground conditions. For above ground conditions, the European prestandard ENV 12037 and EN 330 are used to determine the durability of treated wood. The most important factors for fungal establishment on the surface and within wood are the moisture content, the surrounding temperature, and the relative humidity. Strength tests are the most sensitive for decay detection, but neither strength tests nor identification of fungi responsible for the decay are included in the standards of above ground durability in field tests. To detect decay, visual examination, pick or splinter tests, and mass loss determination are used. Identifying fungi with traditional methods, e.g., growth on solid medium, is time consuming and complicated. Molecular methods like polymerase chain reaction and sequencing do not require mycological skill for identification to species level, and furthermore the methods do not depend on the subjective judgement like most traditional methods, but are based on the objective information of the target organism (e.g., nucleotide sequences). The next generation of standard field tests will probably consider the drawbacks of standard tests today and be rapid and include both quality tests like molecular identification and nondestructive quantitative tests, e.g., acoustic tests. Laboratory tests can be improved by using fungi identified from field trials and by combining different fungi in the same test and thus simulate degradation in practice.