Crowded house : a Corymbia/Allocasuarina Woodland Association unburnt for 18 years in Central Queensland

Thickening of woody vegetation and reduced ground cover is recognised world wide, as one consequence of long term grazing and fire exclusion.This successional change impacts grazing values, native forest species persistence and biodiversity values. The restoration of a regular fire regime is one method which may not only limit structural change but encourage the germination of the remnant native grasses and legumes. This project is part of a wider study which aims to develop management tools for landholders which have an ecological basis. A ten hectare site of eucalypt associations with a dense mid-layer of Allocasuarina littoralis (oak) has been divided into 4 random blocks which test 4 disturbance treatments. These are spring fire, chemical thinning, chemical thinning and fire and a control. The strand structures on each block are described using permanent transects which also give an indication of the species mortality and the production of oak cones. Ground layers are described by frequency of occurrence and cover. As well fuel weights, composition, curing and dryness are recorded pre- burn. A series of hemispherical photographs before and after the treatments will record any significant changes to the canopy characteristics of the stands. Weather data for the location is collected with an automatic weather station and soil moisture information is collected on each treatment site. Aerial photographs, since 1953, indicate that this site has had a largely closed canopy until present time. However intensive grazing has been a disturbance since the late 19th century. Ground cover species of native tussock grasses and legumes are persisting at the site albeit in low biomass and low species richness. The emergent canopy species are over 90% Corymbia (bloodwood) species which contribute 62% of the woody, basal area. Oak stems, which occupy the remaining 38% of the woody basal area, number approximately 3500 per hectare mostly under10 centimetre diameter.