Causes of incipient rot and rot in regrowthEucalyptus diversicolor(karri) trees

Abstract

Eucalyptus diversicolor (karri) is the second most important commercial timber tree in Western Australia. Sawlogs from regrowth trees often have a discoloration in the heartwood that is more abundant than in sawlogs from mature trees. Other symptoms in regrowth logs include white rot, white pocket rot and brown rot. Fungal isolations and pathogenicity tests were conducted to determine whether this discoloration was incipient rot, and if so, what caused it and which rot(s) would eventually develop. A combined sample of 329 discs from recently felled trees and freshly cut scantling had discoloration in 48%, white rot in 14%, white pocket rot in 12% and brown rot in 4% of pieces of wood. Hymenochaete semistupposa was isolated from 22% of discoloured wood and 39% of white pocket rot samples. Stereum hirsutum was isolated from 4% of discoloured wood and 13% of white rot samples. Koch's postulates in regrowth karri trees showed that H. semistupposa caused extensive discoloration, with white pocket rot developing in the heartwood within 4 years, while S. hirsutum caused extensive discoloration, with white rot developing in both the heartwood and sapwood within 2 years. It was concluded that the discoloration was incipient rot, which would eventually develop into either white rot or white pocket rot.

Forest health surveillance in Western Australia: a summary of major activities from 1997 to 2006

“…The fastest-growing trees were those most likely to be infected. The fungi most commonly isolated were Stereum hirsutum and Hymenocheate semistupposum (Davison and Tay 2008). No further forest surveys were conducted, but sawmill surveys showed that incipient rot and rot were significantly greater in saw logs from regrowth stands than in those from mature stands (Donnelly and Davison 2008).…”

The contest for the tall forests of south-western Australia and the discourses of advocates

“…Thus, managing stands for the persistence and replacement of mature trees may contribute to long-term fuel reduction in Australian forests and woodlands. (Wilson et al 2018, p. 353;SV12) Given relatively slower than expected growth rates in regenerating karri (Prior et al 2011;Wood et al 2015), the presence of Armillaria fungus (Robinson et al 2003) and reduced wood quality (Davison and Tay 2008;Donnelly and Davison 2008), the two-tiered forest available for logging may be fully exploited before regrowth, becoming suitable as saw-logs ( Fig. 5…”

First record of Cryptosporiopsis actinidiae in Australia

“…In 1986 a large number of fungal isolations were made from rot and discolouration in karri trees (Eucalyptus diversicolor) from regrowth stands in the south-west of Western Australia (Davison and Tay 2008). This was part of a study to determine which fungi caused these symptoms and whether all symptoms of discolouration would ultimately develop into rot.…”