Underpinnings of fire management for biodiversity conservation in ...

Fire and adaptive management
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Chapter 2 Track networks, fire
suppression and the environment
Introduction
In chapter one, reasons why active fire management is needed were outlined. One of the reasons
for intervention is the need for fire suppression. In this chapter, fire suppression from the ground,
using tracks for access, is considered. The role of aerial attack is considered later in the publication.
An examination of the theory of tracks, from a fire-management perspective, is conducted and a
consideration of the effects of tracks on the environment generally is explored.
Tracks can resist the spread of some fires even in the absence of suppression crews and equipment,
but their effectiveness can be improved by modifying adjacent fuel arrays so that any fire that
occurs has minimal intensity. Tracks can be connected to natural fuel breaks, such as rivers, thereby
expanding the network. Tracks may be in place at the time of a fire, but the firefighting operation
itself may create new tracks using bulldozers, graders and hand tools (such as rake-hoes).
The length and width of tracks necessary for suppression to be effective is often debated (Andrews
1990), especially after major fires. This is reflected in the reports of official inquiries into major
fire events (e.g. Esplin et al. 2003, p. 49; McLeod 2003, pp. 94–100; Nairn 2003, pp. 31–40,
and in Organ’s accompanying dissenting report, Countering the case for more fire trails). Ellis et
al. (2004, p. 255) noted that track access has been a consistent theme of inquiries since 1939.
Usually, communities affected by fires call for more and wider tracks, but these calls come with no
quantitative suggestions. Nairn (2003, p. 27) recommended that the subject be investigated.
The potential environmental impact of track networks is discussed in a later section of this chapter,
as a prelude to the discussion of the theory of track networks. Impact can vary widely according
to ecological context. For example, some soils are more erodible than others. Modifications to the
environment, caused by track networks, can affect biodiversity directly or through the modification
of habitat. Some organisms may be favoured by the presence of the track network; others may be
adversely affected.
Track establishment and maintenance usually involves a wider swathe than that of the final track
surface as verges are created (Goosem 2004). Grading, slashing and other actions, such as cutting,
mowing or spraying of herbicides may occur (Andrews 1990), thereby tending to maintain disturbed
habitat. Informal rest areas and temporary dumps of road-maintenance materials may occur on
verges. In forests, removal of trees on verges may be favourable to some weeds because of the
disturbance that accompanies the process and because of the enhanced growing conditions. Tree
removal along roads and major tracks, up to about one-tree height from the forest edge, was a
feature of works carried out after severe fires in parts of the ACT following the January 2003 fires.
Large trees, leaning trees, hollowed trees and dead trees are likely to be targeted in such programs
due to the chance of their falling on cars or people, or blocking roads.
Establishment of tracks and modifying the adjacent fuels can affect biodiversity directly or indirectly, as
reported later in the chapter. Firstly, however, a note of track types is presented.
Track types
Tracks usually take the form of paved roads, formed earth roads and rough tracks suitable for
vehicular access during fires. At various times they may be called fire trails, containment lines, fuel
breaks, control lines or access routes, according to the circumstances. In this discussion, tracks (cf.
rivers etc) are formed directly or indirectly to support wheeled fire-suppression vehicles. Note that
buffers (fuel-reduced strips rather than bare-earth breaks) are not considered to be tracks for the
purpose of this discussion. These will be considered later. Areas under powerlines may generally be
thought to be buffers and free of tracks, but ‘all utility corridors have access roads’, according to
Andrews (1990), although they may be very primitive in places.