Survey of eucalypt dieback in Mt Cole State Forest, with special reference to armillaria root rot.  R. G. Runnalls and G. Y. Forward.  August 1982.  18 pp. (unpubl.)

SUMMARY

This report describes the results of a ground survey during 1979 of eucalypt dieback in 2303 ha of Mt Cole State Forest, near Beaufort in west-central Victoria. The basal area at least ten healthy and/or dieback-affected trees above 15 cm DBHOB (diameter at breast height over bark) was measured at each of 285 sample points located systematically throughout the survey area. Also determined where the species of each eucalypt present, the level of dieback and the crown position of all assessed trees in the forest canopy; the health status of associated Acacia spp; the slope, aspect and soil type; and the basal area of all stumps less than 30 years old. The etiology of crown dieback was also examined.

Approximately 11% of the total basal area of trees in the survey was found to be affected by dieback, 4.2% being due to Armillaria luteobubalina Watling and Kile (root rot fungus), 2.6% to fire, 2.4% to other causes including logging damage, ringbarking and mistletoe attack, and 1.9% to unknown causes. The pathogen was associated with unhealthy tree crowns at 23% of sample points and was most prevalent in the taller stands and least frequent on slopes above 15°.

A total of 332 ha of diseased forest, distributed over 17 areas varying in size between 4.4 and 77.3 ha, have been mapped and arranged in decreasing order of infection severity, to facilitate scheduling for treatment to reduce inoculum levels of A. luteobubalina during harvesting.