Mistletoes Increasing in 'Undisturbed' Forest: A Symptom of Forest Decline Caused by Unnatural Exclusion of Fire?(Report‪)‬

Introduction Increasing populations of mistletoes in rural areas of Australia have been reported by many observers since the late nineteenth century but no data have been published to confirm these reports (Reid and Yan 2000; Ward 2005b). Reid and Yan (2000) suggested that the perceived increases were due to better habitat provided by more vigorous trees responding to increased water and nutrients as a result of partial clearing and development. They suggested that mistletoes were not generally regarded as a problem in public forests and conservation reserves. However, mistletoes have long been perceived as a problem in the box-ironbark forests of north-central Victoria where extensive areas of forest were treated, from the 1920s to the 1950s, to remove dodder-laurel vines (Cassytha melantha) and mistletoes (Kellas 1991). Jacobs (1955) stated that 'the mistletoe problem has attracted considerable attention and work is being undertaken by CSIRO, the Forestry and Timber Bureau and the Forest Departments to counter the pest' by sprays, injections and lopping. In the conservation reserves of the Mount Lofty Ranges, South Australia, 29% of pink gums, Eucalyptus fasciculosa, are currently infected by mistletoe, and infected trees have 58% canopy dieback (Ward 2005a). High densities of mistletoes are now apparent in some stands of trees that were not normally susceptible to infection, such as blackbutt, E. pilularis, in Peachester State Forest in south-eastern Queensland (pers. obs. VJ).