Bio-deterioration of Pinus radiata round wood preserved with CCA salt against brown rot fungi

Abstract

In Chile, Pinus radiata wood has been classified as not durable according to Chilean standards NCh789. To increase its durability it is required to impregnate it with type CCA (copper, chromium, arsenic) soluble salts. The aim of this study was to analyse the effectiveness of the impregnation of five P. radiata round wood treated with this salt. From each 260 cm long round wood a disc was removed from one end, which withdrew a central strip that provided the samples for determination of preservative retention by calcinations and bio-deterioration through accelerated laboratory tests using two brown rot fungi, Gloeophylum trabeum and Poria placenta. It was observed, in the five samples of round wood, that the penetration of the preservative was irregular and pond shaped; covering between 40 to 80 % of the total area, with little consistency in the retention and focusing on the periphery of discs. The preservative salt retention reached 4.3 to 10.5 kg m^-3 on discs periphery, while in the inner zone, close to the pith, the retentions were 0.3 to 3.1 kg m^-3. The specimens from the periphery of the round wood subjected to attack by xylophages fungi showed a mass loss of 1 %, classifying the impregnated CCA wood of P. radiata as highly resistant and in the inner zone, close to the pith, mass loss reached 26 %, moderately resistant.