Empirical-based models for predicting head-fire rate of spread in Australian fuel types

Summary

The knowledge of a free-burning fire’s potential rate of spread is critical for safe and effective bushfire control and use. A number of models for predicting the head-fire rate of spread in various types of Australian vegetation have been developed over the past 60 years or so since Alan G. McArthur began his pioneering research into bushfire behaviour. Most of the major Australian vegetation types have had more than one model developed for operational use. These include grassland, shrubland, both dry and wet eucalypt forests, and pine plantation fuel types. A better understanding of the technical basis for each of these models and their utility is essential for the correct selection and application of the most appropriate models. This review provides a systematic overview of 22 models of the rate of fire spread and their applicability in prescribed burning and wildfire operations.

Background information and a description of each model is given. This includes information on the data used in the model development that defines the bounds of its application. The mathematical equations that represent each model are given along with a discussion of model form and behaviour, the main input variables and their influence, and evaluations of model performance undertaken to date.

This review has enabled the identification of those models that constitute the current state of knowledge with respect to bushfire behaviour science in Australia. We recommend the models that should underpin best practice in the near term in the operational prediction of fire behaviour and those that should no longer be used, and provide reasons for these recommendations.

Keywords:

• fire
• fire behaviour
• fire spread
• propagation
• burning
• fire weather
• fire danger
• environment
• models
• experiments
• fuels
• characteristics
• moisture content
• prescriptions
• slope
• wildfire

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Corrigendum

Acknowledgements

We would like to acknowledge Phil Polglase of the CSIRO Land and Water Flagship Forest Systems group for supporting this work and the Bushfire Cooperative Research Centre (in particular Gary Morgan) for enabling this work to be completed in a timely manner. Thanks to Kelsey Gibos and Matt Plucinski for critical reviews of earlier versions of this document.

We would like to pay tribute to the inspirational ground-breaking work of A.G. McArthur followed by G.B. Peet and N.P. Cheney, without which we would be unlikely to have attained the capacity we enjoy in Australia today to predict the rate of spread of fire. Finally, we recognise the cast of unnamed hundreds who participated in the collection of data from experimental fires over the past six decades that have made it all possible.