Geographic variation in the demographic structure of stands of Eucalyptus delegatensis R.T. Baker on dolerite in Tasmania

Abstract

Eucalyptus delegatensis is a widespread dominant of montane forests in southeastern Australia, where it occupies sites of widely varying moisture status and understorey type. The age and size class distributions of E. delegatensis on twenty-three sites of varying precipitation over its range on dolerite in Tasmania are strongly related to the floristic composition of the understorey vegetation and to moisture availability. No stands are even-aged, but all stands exhibit evidence of periodic rather than continuous recruitment, the periodicity of past recruitment events increasing with more mesic conditions. There is evidence for a change towards less frequent recruitment events in the higher rainfall stands since white settlement. An explanation for the variations in regeneration patterns is sought in the complex interactions between climate, fire frequency, fire intensity and understorey vegetation type.