Fire Behaviour

Abstract

The effect of fire on natural ecosystems depends on the response of living organisms to the release of heat energy through the combustion of plant material. The expression fire behaviour describes the release of heat energy and is dependent on fire intensity, rate of spread of the fire front, flame characteristics and other related phenomena. The manner in which heat energy is released and the factors that influence this currently form the basis of any study of fire behaviour. Such a study necessitates a basic understanding of the phenomenon of combustion. Brown and Davis (1973) state that combustion is an oxidation process comprising a chain reaction in which the heat energy from fire originates from solar energy fixed by the process of photosynthesis. Combustion is similar to photosynthesis in reverse and is clearly illustrated in the following two general formulae: Photosynthesis

$${\text{C}}{\text{O}}_2 + {\text{H}}_2{\text{O}} + {\text{solar energy}} {\underleftarrow \to} ({\text{C}}_6{\text{H}}_{10}{\text{O}}_5)_{\text{n}} + {\text{O}}_2$$

(1)

Combustion

$$({\text{C}}_6{\text{H}}_{10}{\text{O}}_5)_{\text{n}} + {\text{O}}_2 + {\text{kindling temperature}} {\underleftarrow \to} {\text{C}}{\text{O}}_2 + {\text{H}}_2{\text{O}} + {\text{heat}}$$

(2)