Wood losses through Eucalyptus dieback associated with Phytophthora cinnamomi in eastern Victoria.  P. C. Fagg.  June 1980.  15 pp. (unpubl.)

SUMMARY

In 1972 a compartment of 923 hectares of lowland eucalypt forest, near Orbost in eastern Victoria, was studied to determine the losses in merchantable would volume and royalty due to mortality, which had occurred in 1971. The study showed that Phytophthora cinnamomi occurred throughout the area, and that most mortality could be attributed to crown dieback caused by this fungus.

The study area contained a number of eucalypt species of mixed age, with a mean dominant height of 31.4 m. This area was fairly typical of much of the lowland forest between Orbost, Lakes Entrance, and Nowa Nowa in eastern Victoria.

Estimates were made of wood losses due to mortality on eighteen 0.12 ha plots. On each plot, living and dead trees were recorded according to species, diameter, merchantable volume, crown class and potential merchantability, and the presence or absence of Phytophthora spp. and Pythium spp. was determined.

Recent mortality amounted to 6.6% of total sawlog volume, and to 10.3% of pulpwood volume; this was estimated as a total direct royalty loss of 8.7%, or $8.72 ha^-1 in 1972. Indirect losses, due to possible reduction in the growth rates of living but diseased trees, were not measured in this study. If an integrated sawlog-pulpwood harvesting operation had been carried out in the area soon after the dieback was manifest, then a large proportion of the wood in the dead trees could have been salvaged.