An investigation of the factors influencing the rate of deterioration of timber samples due to microfungi in laboratory tests

IRG/WP 97-20116

I J Herring, D J Dickinson, S M Gray, J K Carey

An investigation was performed into the comparative performances of test 1 (vermiculite burial) and test 2 (soil burial) as described in ENV 807. Two test preservatives were used - copper naphthenate and propiconazole. Copper chromate was included as a reference preservative. The wood species used was beech (Fagus sylvatica). Test 1 was performed using both a mixed inoculation of the five stipulated softrot fungi, and separate monocultures of the test fungi. This enabled an assessment to be made of the individual performance of each fungus with the various preservative types, highlighting any incidence of preservative tolerance. Test 2 was performed as described in ENV 807. Isolations were made from test blocks in both tests where weight loss approached 3% m/m. In test 1 isolations were performed on samples from the mixed inoculation test, and in test 2 every 8 weeks throughout the 32 week duration. The results of this investigation show that the tests do not yield comparable results. Test 2 proved to be a more virulent system. The vermiculite test can only be relied upon when the microbial ecology of the treated wood in practice is known, as with copper naphthenate.


Conference: 97-05-25/30 Whistler, British Columbia, Canada

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