A comparison of fire danger rating systems for use in forests

Fire danger is the resultant of ‘factors affecting the inception, spread and difficulty of control of fires and the damage they cause’ (Chandler et al. 1983). If any of these factors are absent, then there is no fire danger (Cheney and Gould 1995). Fire danger rating is ‘a fire management system that integrates the facets of selected fire danger factors into one or more qualitative or numerical indices of current protection needs’ (Chandler et al. 1983). A variety of fire danger ratings are used around the world, including the McArthur Forest Fire Danger Index (FFDI, McArthur 1967), used in the eastern parts of Australia, the Forest Fire Behaviour Tables (FFBT, Sneeuwjagt and Peet 1998), developed for use in Western Australia1, the Fire Weather Index (FWI, van Wagner 1987) used in Canada, and the National Fire Danger Rating System (Deeming et al. 1977), used in the USA. Fire danger rating systems are used by fire and land management agencies to determine levels of preparedness, to issue public warnings, and to provide an appropriate scale for management, research, and law for fire related matters (Cheney and Gould 1995). All these systems integrate weather variables to assess fire danger, calculated as a numerical index. Although fire danger is not the same as fire behaviour, the indices were developed on the assumption that fire danger is related to fire behaviour, quantified as rate of spread or intensity. Index values are classified into rating classes to aid interpretation. All systems use five rating classes: Low, Moderate, High, Very High, and Extreme. Similar indices are available for grasslands but are not examined here. In recent years the FWI, originally developed for use in Canada, has been adapted for application in other countries, has been proposed as the basis for a global fire weather index (de Groot et al. 2006), and has been trialled in Tasmania (Mark Chladil, pers. comm.). Also, the FWI system has proved useful when examining fires in pine plantations in Australia (Cruz and Plucinski 2007). In an Australian context it is timely in light of these developments to gain a better A comparison of fire danger rating systems for use in forests