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In spite of these activities, wildfires still occur when conditions
are severe. Fire therefore remains an important environmental factor in
the Australian forest and the management of these areas must take this into
consideration. In planning appropriate management strategies the forested
land manager requires much specific information including data on forest
type distribution and fuel accumulation, prescribed burning history,
wildfire history, accessibility, etc.
This paper concentrates on the methods of providing timely and reliable
maps of the areas burnt in forest wildfires and the patterns of intensity
within the burnt area. This information is of value in determining the
need for rehabilitation as well as for future programming of prescribed
burns. As much of the forest estate receives only extensive management and
protection, low cost approaches to fire mapping are essential.
EXISTING METHODS OF WILD PI RE M AP PING
The methods currently employed to produce maps of wildfires vary
widely, depending on the detail required and the financial and/or manpower
resources available. Each management authority has its different policy
and resources. No attempt will be made to consider the relative merits of
these methods, rather they are presented as methods currently accepted in
practice.
i. Rough field data collection - details of the area burnt and location
of hot spots and canopy scorch are pieced together from information from
fire fighters and supervisors and subsequent field reconnaissance. The
data is presented in map form either directly or through the intermediate
step of plotting details on pre-existing aerial photographs.
2. Detailed field survey - more accurate detail can be obtained and
mapped following field traverses and inspections using consistent survey
techniques (not necessarily sophisticated). Here again, pre-existing
aerial photographs, which can be quite outdated, are invaluable in inter-
polating between the survey lines.
3. Aerial sketch mapping - aerial reconnaissance and sketching of
boundaries onto existing aerial photographs has been used successfully
(Squire, N.S.W. For. Comm., pers. comm.). As light aircraft are involved
and flights can be made under cloudy conditions results can be obtained
shortly after the fire is completed, however good maps depend heavily
on the skill of the observer. It is essential that he know the area in-
timately otherwise aircraft costs increase substantially. The method
suffers from the fact that any errors are difficult to detect or check
without further flights.
4. Special aerial photography - missions of aerial photography, usually
in colour and at scales as large as 1:15 000 can be arranged at short
notice after a major fire, and, together with either random or stratified