Understanding the changing fire environment of south-west Western Australia

Fire environment is the resultant effect of factors that influence the ignition, behaviour and extent of fires in a landscape. This paper synthesises information available from a variety of sources to evaluate evidence for changes over the past three decades in components of the fire environment for south-west Western Australia including climate and weather, fuel, and ignition. A combination of land use, socio-economic and organisational factors has resulted in more widespread extent of lands unburnt for several decades, increasing the risk of high severity fires with adverse impacts on the community and environment. The Mediterranean type climate of the region has become warmer and significantly drier since the 1970s, with associated changes in the timing and duration of the traditional fire season. Lightning ignition has become more common, either as result of greater summer thunderstorm activity or increased opportunity for ignitions to sustain and spread. Increased lightning ignition is significant because of the dis-proportionately large proportion of area burnt by lightning caused fires in SWWA. Adapting to a changing fire environment has implications for all aspects of the fire management business, and a variety of new products and services are available to inform fire managers about temporal and spatial trends in components of the fire environment.