In response to a severe lack of knowledge on the ecological impacts of repeated fuel reduction burning (FRB) in Victorian dry sclerophyll forests, a multi-disciplinary research program was initiated in January 1984 by the then State Forests and Lands Service of the Department of Conservation, Forests and Lands (DCFL). The ambitious study was stimulated not only by constant and often intense criticism of FRB but also by a Symposium held at Monash University soon after the catastrophic 1983 Ash Wednesday fires on “Fighting fire with fire” (Ealy 1984). The study was conducted in the Wombat State Forest some 80km northwest of Melbourne.

The broad objectives of the program were to assess and describe the effects of repeated spring and autumn fuel reduction burning on:

• the flora, fauna and soils;
• the functional processes of dry sclerophyll forest ecosystems; and
• the short and long term stability of such ecosystems.

Detailed records of fire histories and forest type information across the Wombat Forest were used to identify suitable Study Areas which had not been burnt for 18 years. These Study Areas were then subject to detailed surveys of species, tree size, visible hollows and other relevant pre-treatment data.

Using a randomized block design to ensure statistically valid findings for most animal groups included in the study, the five blocks (Study Areas, each 10ha in size) of the Messmate/Gum Forest were each subject to five treatments as follows:

• Burning as often as possible in spring;
• Burning as often as possible in autumn:
• Burning on a 10 year rotation in spring;
• Burning on a 10 year rotation in autumn; and
• Control, long unburnt.

To meet the ecological objectives of this long-term study, permanent plots were established on all treatments across the five Study Areas to examine responses to fire of understory vegetation, overstory trees, invertebrates, litter and soils. Mammals and birds were studied across the whole of the Study Areas.

The study involved scientists and technicians from a wide range of research bodies and independent scientists with expertise in flora, fauna and soils, and was led by Kevin Tolhurst. In 1992, an exceedingly detailed first progress report (275 pp) was published in the DCFL Forest Research Report series (Tolhurst and Flinn 1992). Soon after, a summary of this work was published and made widely available. This summary (Tolhurst et al 1992) is provided in full below, with the interim findings leading to significant changes in the conduct of fuel reduction burning in the foothill forests of Victoria.

In 2003, a second contracted progress report for the period 1984 to 1999 was released by the then Prof. K Tolhurst who had remained the Manager of the Research Program and principal scientist since its inception (Tolhurst 2003). The findings in this milestone report had profound and long-lasting implications for the future conduct of FRB in Victorian foothill forests. FRB guidelines were progressively revised over this period and completely new approaches to the assessment of fuel hazard involving inter alia the role of bark and understory vegetation to more precisely assess fuel hazard in the foothill forest across Victoria. This led to the publication of an Overall Fuel Hazard Guide, and the Code of Practice for Fire Management on Public Land was progressively modified as results from the Wombat study were published. Likewise, Guidelines for Ecological Burning on Public Land in Victoria were also progressively revised. Importantly, these revisions took full account of those burning practices that were shown to have adverse impacts on bats, terrestrial mammals, reptiles, invertebrates, fungi, birds, soils and tree growth.

As noted In the Foreword to the 2003 report, “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”. This underlines the importance of long-term monitoring of fire effects. Turner (2023) reviewed 46 long-term ecosystem studies in native forests in Eastern Australia which he noted are essential to maintain and improve forest management practices. He found that few studies met their long-term objectives and considered that the Wombat study was one of the most important and successful Long-term Ecological Studies investigated in his analysis.

Tolhurst (2012) addressed the issue of forest ecosystem resilience and fire severity. Using the findings of the long-term Wombat study, he concluded that this forest demonstrated “a high resilience to fire” which he attributed to the patchiness and variability in fire characteristics of FRB, combined with the relatively small proportion of the landscape being affected. This contrasts to the often-major ecological impacts of large and intense wildfires. His work combined with further understandings from on-going research and the profound management implications of the research findings will continue to provide the scientific underpinning of FRB in Victorian forests.

References

Ealy, E.H.M. (Ed.). Fighting fire with fire, Proc. Symp. on fuel reduction burning, 17-18 Sept. 1983, Monash University, Melbourne, 215pp.

Tolhurst, K. G. 2012. Fire severity and ecosystem resilience-Lessons from the Wombat fire effects study (1984-2003). Proc. Royal Soc. Of Vic. 124:30-37.

Tolhurst, K. G. 2003. Ecological effects of repeated low intensity fire in a foothill forest in south-eastern Australia: Summary report (1984-1999). Department of Sustainability and Environment, Fire Research Report No 57, 86pp.

Tolhurst, K. and Flinn, D. (Eds) 1992. Ecological impacts of fuel reduction burning in dry sclerophyll forest: First progress report. Dept. Conserv. and Env., Forest Research Report 349, 275pp.

Tolhurst, K. G., Flinn, D. W., Loyn, R. H., Wilson, A. G. and Foletta, I. 1992. Ecological effects of fuel reduction burning in a dry sclerophyll forest: A summary of principal research findings and their management implications. Dept. Conserv. and Env., Forest Research Centre, 52pp.

Turner, J. 2023. Perspectives: Long term forest ecosystem studies in Eastern Australia. For. Ecol. and Manage., 549:1-7.