Micromorphology of decay in Keruing heartwood by the basidiomycetes Phellinus contiguus and Dacrymyces stillatus
G Kleist, M Ray, R J Murphy
This study aimed to characterise the micromorphology of fungal decay in a wooden handrailing in an above ground exposure at the Thames embankment in London. Keruing heartwood (Dipterocarpus spp.) was determined as the construction timber and the two basidiomycetes Phellinus contiguus and Dacrymyces stillatus identified as main decay organisms.
Their decay patterns within Keruing heartwood were studied using light microscopy. Besides typical white and brown rot decay features the analysis also revealed cavities in the fibre S2 wall layers. A laboratory screening test with monocultures of both fungi confirmed their individual ability to form rhomboidal shaped cavities similar to those commonly associated with “true” soft rot fungi.
This form of attack indicates that typical soft rot-like cavities can also be formed by white and brown rotting basidiomycetes facultatively and are therefore not an absolute indication for the occurrence of soft rot causing asco- and deuteromycetes respectively.
Keywords: Keruing, Dipterocarpus, Phellinus contiguus, Dacrymyces stillatus, biodegradation, brown rot, white rot, soft rot, basidiomycetes