The fire environment of five Australian cities

Destructive bushfires which destroy buildings and inflict loss of human life regularly afflict the cities of the Australian east coast. A review of the incidence of destructive bushfires revealed their relative absence from Greater Brisbane compared to the other east coast capital cities of Sydney, Canberra, Melbourne and Hobart, despite all cities occurring in the forested eastern region of the continent. This study examines three factors that influence the incidence of destructive bushfires and attempts to assess the vulnerability of these Australian cities. The incidence of days with extreme Forest Fire Day Index (FFDI) values (> 50) was highest for Melbourne and lowest for Hobart. Wind directions on these extreme days was generally from inland areas where forest is associated with the urban fringe. Wet sclerophyll forest, which represents a substantial hazard, fringes parts of Melbourne and Hobart, while Brisbane and Canberra adjoin a higher proportion of cleared areas which alleviate the impact of destructive fires. Fine fuels decline from south to north and are thus highest in Hobart and lowest in Brisbane. The incidence of hazardous fires can be related to a composite of these three factors and indicate that Melbourne is most prone to destructive bushfires and Brisbane least prone. Climate change projections indicate that the incidence of extreme FFDI values will increase on the Australian east coast exaggerating the impact of destructive fires.