Underpinnings of fire management for biodiversity conservation in ...

6
Fire management – especially fire suppression
Fire management – defined as consisting of actions that directly or indirectly affect the presence of
fire or its behaviour 5 – may be seen as the set of actions involved in the preparation for and practice
of suppression of unplanned fires, and the preparation for and practice of prescribed burning or other
fuel-modification techniques. In other words, there are pre-suppression or indirect operations and
direct suppression operations. Prescribed burning, in this classification, would be a pre-suppression
measure. This is not to deny that prescribed fires may be ignited for ecological reasons, as well as
increasing the chance of quickly extinguishing unplanned fires during a fire event.
In this section, an outline of methods and limitations of direct fire suppression is given. Prescribed
burning is considered in detail in chapter three. If a prescribed fire gets out of control the same limits
apply to it as they do for any unplanned fire.
Fire suppression
Direct fire suppression is effected by spraying water or chemicals on a fire or just in front of it, creating
mineral-earth fuel breaks in the fire’s path and burning out the fuel between the fire front and the
fuel break surrounding the fire. A short classification of techniques for fire suppression follows:
1. Use of water or retardant chemical – Placement of water, with or without foam suppressant, or
flame retardant on or adjacent to fuels using light units (small 4WD tray-back utilities with pump
and relatively small water tank e.g. 400 litres), 4WD tankers and fixed-wing or rotary winged
aircraft.
2. Use of narrow fuel breaks – Narrow fuel breaks may be established using rake-hoes or other
hand tools and are usually used in forest country with litter fuels.
3. Use of relatively wide fuel breaks – These may be established using graders or bulldozers; the
former usually in grassland, the latter in forests.
4. Use of fuel removal by burning out – This is usually carried out when weather conditions are
relatively mild (e.g. during the night), in order to remove all the fuel between the fire perimeter and
a fuel break (containment line). The idea is that as weather conditions become more severe the
following day, the fuel to support a high intensity fire will be absent or markedly reduced.
Many suppression operations involve a combination of some or all of the above techniques.
Direct suppression is often followed by mopping up or blacking out close to, or adjacent to, a fuel
break. This is the process of putting out all smouldering materials that may allow the later flaring up
of the fire and, perhaps, its spread across the fuel break.
Limits to fire suppression
While experts may not take seriously the idea that suppression will be immediate and always effective,
the public often treat it seriously and with confident expectation. This section explores the limits
to suppression, even when using high technology: helicopters and other aircraft; modern 4WD
tankers with chemical enhancers in water held in high capacity tanks; sophisticated communications
networks; remote sensing of hot spots; computer predictions of fire behaviour; explicit command
structures and procedures; automatic tracking systems for appliances; and well-trained and equipped
personnel.
5 A wider definition of fire management may include equipment purchases and maintenance; crew recruitment, training and retention; fire
detection; forensic determination of fire cause; community liaison and law enforcement.
Fire and adaptive management Underpinnings of fire management for biodiversity conservation in reserves