Assessing the natural durability for different tropical timber species using the mini-block test

The Xylarium in the Royal Museum for Central Africa (RMCA, Tervuren, Belgium) contains over 60,000 wood-samples, comprising over 12,000 species. These samples are of great historical and scientific value yet have a random format, which complicates standard testing. The wood-durability against Coniophora puteana and Trametes versicolor was tested for 36 species. Due to the random sample sizes the standardised test for testing durability related to basidiomycetes CEN/TS 15083-1 (2005) was not applicable as such. Instead, the mini-block test, as proposed by Bravery (1978) was used. The similarity between the standard test and the mini-block test will be assessed for 13 reference species. Virulence check for both test fungi was performed using beech, Fagus sylvatica L. For both Coniophora puteana and Trametes versicolor a standard durability only allowed standard classification according to durability class DC 2 when referring to the criteria set in EN 350 (2016), showing that the fungal growth was not optimal. There appears to be no direct link between the mass loss of the tested species using the criteria and the durability class listed in EN 350 (2016). Prior to fungal testing the same samples were also chemically analysed, by DART TOFMS to check potential correlation between ion-intensity and mass loss. Several ions which are linked to certain compounds or metabolites, appear to play an important role in explaining the variability in mass loss between samples.

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