Soft rot in heartwood of preservative-treated pole stubs of Eucalyptus cypellocarpa L. Johnson
IRG/WP 1204
J E Barnacle, G C Johnson, M A Tighe
Pole stubs of Eucalyptus cypellocarpa L. Johnson, treated in the sapwood with certain waterborne preservatives and exposed for 21 to 23 years in a dry tropical region were severely soft-rotted in the heartwood, as well as the sapwood. They broke with a brash fracture when stress tested (loaded as a cantilever) in the field. The severe soft rot in the heartwood was not detected by the knife test or the Shigometer. Similar stubs, treated with oilborne preservatives, showed no microscopic evidence of soft rot in the heartwood and the few which have broken under load did so with a tension-type fracture. Implications of these findings for future testing of soft rot susceptibility of eucalypt heartwood within a treated annulus are discussed.