Underpinnings of fire management for biodiversity conservation in ...

Fire and adaptive management
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Chapter 3 Prescribed burning
as a fuel-modification measure
Introduction
In chapter two, the value of tracks in fire suppression was examined in the context of biodiversity
conservation. From the point of view of stopping a fire, the fire property examined in grasslands
(without trees and other significant sources of brands) was the length of flames in relation to the
width of the track in the fire’s path. In eucalypt forests in which the production and spread of fire
brands is significant, tracks were useful for stopping fires, but only over a limited range of intensities.
Therefore, the modification of the fuel array throughout a significant proportion of a forest area, to
minimise the production and dissemination of airborne burning materials, may be advocated. With
reduced fuel loads and modified fuel structure, the potential for spread by fire brands can be reduced
for a number of years.
A common cost-effective way to reduce fuel loads and modify fuel structure, especially where woody
fuels are predominant, is to use fire under defined and low-risk conditions – prescribed burning (Text
Box 3.1; Plate 3.1). Prescribed burning reduces the fuel load, fuel continuity, loose lower bark of trees
and, initially at least, the proportion of dead-to-live fuel contained within the fuel array. Therefore,
by definition (see Chapter 1), the potential fire intensity is reduced. It may then be argued that this
in turn increases the chance of controlling the fire, and therefore decreases the chance of the loss of
human life and economic assets.
Another broad-area technique is the use of grazing animals to reduce fuels, especially where grassy
fuels predominate – even in forests. This will be examined in the next chapter. In this chapter,
prescribed burning as a fuel-reduction measure is considered in light of conservation objectives.
Plate 3.1 Prescribed low-intensity fire for fuel reduction (Graham 2004).