Comparative changes in Eucalyptus pauciflora (Myrtaceae) stand structure after bushfires in Victoria

The recent frequency and extent of landscape-scale fires in subalpine areas of Victoria have led to almost all Eucalyptus pauciflora (snow gum) forests and woodlands being burnt, to the extent that old growth stands are now rare. A comparison of Eucalyptus pauciflora stand structure at three mountains with comparable geology, altitude, topography and grazing history but with different fire histories revealed three regeneration syndromes: (i) long-unburnt stands consisting of few-stemmed trees at Mt Baw Baw and recently-burnt stands at Lake Mountain, both characterised by a single establishment phase in response to fire disturbance; (ii) long-unburnt stands consisting of few-stemmed trees at Mt Buffalo, characterised by continuous regeneration and ongoing seedling recruitment independent of major disturbances, and (iii) multi-burnt stands with high tree density and thin stems at Mt Buffalo, with multiple stem establishment phases. At some sites with very high fire frequency and/or short inter-fire intervals, multi-or thin-stemmed architecture may have become entrenched. Post-fire seedling recruitment is high but seedlings are likely to be outcompeted and remain in a suppressed state. Snow gum is a tenacious niche persistor with capacity to resprout after multiple fires but the current outlook is one of a radical demographic shift in population structure in subalpine landscapes. It is crucial that remaining long-unburnt Eucalyptus pauciflora stands are protected from fire as far as is practicable to allow stand development and to preserve the unique quality and function of mature snow gum woodlands