INTRODUCTION 
By world standards the forest resource of Australia is quite limited. 
Only six per cent of the total land surface is covered by productive or 
potentially productive forest. Of this area of approximately 42 500 000 ha 
almost 85 per cent is covered by sclerophyll forests dominated by species 
of the genus Eucalyptus. A further 10 per cent is occupied by dry com- 
munities which include the native conifers, Callitris spp., but which also 
include eucalypt species. The sclerophyll forests fall into two broad 
categories (Luke and McArthur 1978). Their floristic differences are also 
reflected in their behaviour when burnt by forest fires. 
The wet scleropyll forests are tall forests (30-50 m) generally with 
two or three layers of shade tolerant trees, a dense understorey of shrubs 
and ferns with grasses in the more open situations. They are found in the 
higher rainfall areas of Queensland, New South Wales, Victoria, Tasmania 
and the extreme southwest corner of Western Australia. Fuel quantities 
tend to be much higher than in the drier forests and during extended 
drought periods these forests can become highly flammable. The eucalypt 
species in this category are generally fire sensitive and extensive areas 
of this type of forest have been killed by high intensity fires in the 
past. 
The dry sclerophyll forests are communities possessing a dominant tree 
layer with a well developed layer of xeromorphic shrubs. They are shorter 
and more open than the wet sclerophyll forests and seldom exceed 30 m in 
height. They cover large areas in eastern Australia, Tasmania and Western 
Australia and they occur in restricted areas of South Australia. These 
forests are flammable in most years but as most of the species are fire 
resistant, trees are seldom killed outright even by high intensity fires. 
Rainfall distribution and other weather influences combine periodically 
to provide severe fire seasons when forest areas totalling as much as 
1 000 000 ha can be affected by wildfires. The fire seasons, which can 
extend for long periods, vary from state to state. 
Most of the eucalypts are well adapted to withstand the effects of 
fire and except for seedlings and to some extent saplings, few eucalypts 
are killed outright by fire. Only a small group of species, the ash group 
(which includes the world's tallest growing hardwood Eucalyptus regnans) 
is susceptible to fire as mature trees. 
Considerable effort has been devoted by the Australian forest services 
and other forest owners to study fire weather, fire behaviour, fire effects, 
methods of detection and suppression, etc. Significant achievements have 
been made, fire suppression activities are now highly organised and their 
efficiency is being continually reviewed. In most States there are exten- 
sive programs of prescribed burning (totalling 800 000 ha in 1976) which 
aim to reduce hazardous fuel loads to assist wildfire control. These low 
intensity fires (less than 500 Kw/m) are burnt under the forest canopy at a 
time of low fire danger (Myers 1978).