Ecological Effects of repeated low-intensity fire in a mixed eucalypt foothill forest in south-eastern Australia summary Report (1984 - 1999)
Research Report No. 57
The vegetation, topography and climate found in south-eastern Australia combine to make the region one of the most wildfire-prone areas on Earth. It has been estimated that, in the last one hundred years, two-thirds of all of Australia’s bushfire-related human deaths have occurred in Victoria, as has more than half of all significant related property losses.
Conversely, over tens of thousands of years, naturally occurring fires have been highly significant in shaping the distribution and composition of much of the region’s native flora and fauna. The arrival of humans in this part of the world is also considered to have had a more recent influence on these evolutionary processes.
Dealing with this paradox, the threat posed by fire to life and property and the relationship between fire regimes and biodiversity are arguably the key on-going issues confronting the managers of Victoria's parks and forests.
The severity of a bushfire depends on topography, weather and fuel conditions. Fuel is the only factor over which a land manager can exert some control. The strategic use of prescribed fire (under specified environmental and fire behaviour prescriptions), generally in spring or autumn, is the only practical method of reducing fuels over significant areas.
The strategic management of fuels, using prescribed fire, has been a key component of park and forest management in Victoria since the late 1950s – early 1960s.
In 1984, the then Victorian Forests Commission established in the Wombat State Forest north-west of Melbourne, what was to become one of the longest-running and most comprehensive studies of the ecological impacts of the repeated use of low-intensity prescribed burning yet undertaken. The location of the study, in part of Victoria’s extensive mixed eucalypt foothill forests is also very significant, as this is where about half of all major wildfires occur, most of the prescribed burning is carried out and where significant rural–urban interface areas are found.
The study is quantitative, multidisciplinary and statistically based. Its multidisciplinary nature is one of its key features. On the same permanent plots understorey flora, invertebrates, birds, bats, reptiles, terrestrial mammals, soil nutrition, tree growth and defect, local climate, fuel dynamics and fire behaviour are being studied, as are their interactions.
In 1992 a major review of the work to date was published, together with a section covering land management implications flowing from the interim results. With the publication of this subsequent ‘Summary Report’ and associated ‘Management Implications’, and nine detailed individual reports, a major milestone in the project has now been reached.
One of the most significant messages flowing from the study is the demonstration that short-term fire effects research can be misleading, given the longevity of forest ecosystems. Of further significance is the influence the research has had on the development of Victoria’s Code of Practice for Fire Management on Public Land. This code, first published in 1995, brought together, in a balanced and unique way, all aspects of wildland fire management into a single document.
The fire effects research has also seen the development of considerably improved techniques for assessing forest fuel hazards. These techniques are now in widespread use across Victoria and interstate and have had a major impact on forest fuel management, fire suppression approaches and firefighter safety.
Similarly, the fire effects study has been a key element in the development of a process for determining ecologically sustainable fire regimes for given areas of park and forest and in the publication of Guidelines and Procedures for Ecological Burning on Public Land in Victoria. Again, the approaches in this area that have been developed in Victoria since 1998 have been adopted in a number of other Australian states.
In terms of the future, the current fire study areas and their treatments are being maintained and the research undertaken to date is set to become an important part of ongoing research that is soon to commence as part of the program of the recently established ‘National Bushfire Cooperative Research Centre’.
In introducing this ‘Summary Report’, I would like to acknowledge the very considerable efforts of the scientists and technical officers who have contributed so constructively to this most significant project. I would like to also pay particular tribute to Dr Kevin Tolhurst, of the University of Melbourne, who has so ably kept the project ‘on the rails’ over the last two decades and who has coped so patiently with many funding and organisational vicissitudes.
In conclusion, the findings summarised here and reported in more detail in the various individual reports provide unique insights, not just for the managers of similar forest types but, in my view, much more widely. The work undertaken since 1984 in the Wombat State Forest is well placed to provide a most useful backdrop to the many future studies still required in other ecosystems. The Wombat work can, in many cases, obviate the need for time-consuming ‘before and after’ research, allowing new work to focus on operational burning regimes, not on expensive experimental burns.
Gary Morgan AFSM
CHIEF FIRE OFFICER
Department of Sustainability and Environment
The 2003 series of other Fire Research Reports developed from the Wombat fire effects study are: