Introduction

Methodologies are described here that may be useful for estimating fire occurrence risk assessment, including the probability of ignition and the spatial spread and intensity of the fire during its lifetime. Two types of risk need to be assessed: (1) fire risk occurrence (hereafter referred to as fire risk), and (2) risk to the ecosystem as a result of fire (hereafter ecosystem risk) (Finney 2005). For purposes of this review, fire risk includes the probability of ignition and the spatial spread and intensity of the fire during its lifetime. Ecosystem risk includes all of the consequences to plant and animal populations and to the soil during the recovery period once the fire has concluded. There is significant understanding of the factors that influence fire risk, with many studies analyzing the long-term consequences to ecosystems (Fairbrother and Turnley 2005). Tools to predict the likely distributional frequency of fire risk under combinations of various conditions are the focus of this review.

The two major categories of fire risk assessment tools are: (1) those that predict fire under current conditions, assuming that vegetation, climate, and the interactions among them and fire remain relatively similar to their condition during recent history; and (2) those that anticipate changes in fire risk as climate and vegetation communities change through time.