Large fires, fire effects and the fire-regime concept

摘要

‘Large’ fires may be declared so because of their absolute or relative area. Huge fires – with areas of more thann106 ha (104 km2) have occurred across a wide spectrum of Australian environments and are known on other continents.nSuch large fires are rare whereas fires with much smaller areas are common. Large fires are initiated by single or multiplenignitions and become large because of some combination of: rapid rates of spread; long ‘life’; merging, and failure ofninitial suppression operations. Fires as ecological ‘events’ occur within a ‘regime’ – an historical series. Both events andnregimes have effects that may be discerned in terms of water, land, air or organisms. What have been regarded as thencomponents of ‘regimes’ have differed between observers, the main issue being whether or not spatial variables need tonbe included; ‘area’ involvement is briefly addressed. The current trend toward fire-regime control through fuel treatment,nincluding management (prescribed) burning, and fire suppression may be expected to continue. These trends, amongnothers, can be expected to change fire regimes. What is regarded as ‘large’ among fires may change as the planet becomesnincreasingly human-dominated.