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, conducted in the Wombat State Forest 80 km northwest of Melbourne, was prompted by both intense criticism of FRB and a Symposium at Monash University following the catastrophic 1983 Ash Wednesday fires. It was led by Kevin Tolhurst.

Study Design and Objectives

The study’s broad objectives were to assess the effects of repeated spring and autumn fuel reduction burning on flora, fauna, soils, the functional processes of dry sclerophyll forest ecosystems, and the short and long-term stability of these ecosystems. Detailed fire histories and forest type information across the Wombat Forest were used to identify suitable study areas that had not been burnt for 18 years. These areas underwent detailed pre-treatment surveys of species, tree size, visible hollows, and other relevant data.

A rigorous, randomized block design was employed, involving five 10-hectare study areas of Messmate/Gum Forest, each subjected to one of five treatments:

• Frequent spring burning
• Frequent autumn burning
• Routine spring burning
• Routine autumn burning
• Long-unburnt control

The design allowed for statistically valid findings, particularly for the various animal groups included in the study.

Multidisciplinary Approach and Key Research Areas

The Wombat Fire Effects Study is one of the few fire ecology studies globally with such a comprehensive, multidisciplinary, and operational scale approach. The study involved scientists from various fields and research bodies, ensuring that interactions between different elements of the forest ecosystem were thoroughly examined.

Disciplines included:

• Understorey vegetation composition and structure
• Tree growth, defect, and bark
• Fine fuels
• Surface-active invertebrates, including annelids
• Birds
• Reptiles (mainly skinks)
• Bats Terrestrial mammals (some arboreal)
• Soils and nutrients
• Weather (continuous hourly records at five automatic stations)
• Fire behavior (intensity, coverage, fuel consumption)
• Coarse woody debris

The study aimed to address key questions, such as the effects of burning frequency (frequent, routine, or none) and season (spring or autumn) on flora, fauna, and fuel. It also sought to understand if the effects of burning frequency differed by season and whether trends in vegetation were influenced by changes to soil properties, vegetation structure, or floristics. The multidisciplinary approach and long time frame allowed for an in-depth examination of underlying mechanisms, such as soil nutrient movements, habitat structure change, and plant and animal population dynamics.

Data Collection and Analysis

Data were collected before treatments were applied, with all sites having remained unburnt for many years. The study’s design allows for a "Before-After-Control-Impact" (BACI) analysis, a powerful method rarely applied at operational scales due to logistic challenges. The availability of pre-treatment data is particularly valuable, enabling differences in fire treatments to be discerned from the confounding effects of successional change, site, and season.

Progress and Findings

In 1992, a detailed first progress report was published, with a summary made widely available. By 2003, a second progress report covering the period from 1984 to 1999 was released. The findings had profound implications for the future conduct of FRB in Victorian foothill forests, leading to the development of new approaches to fuel hazard assessment, including the Overall Fuel Hazard Guide. The study’s results were instrumental in revising the Code of Practice for Fire Management on Public Land and the Guidelines for Ecological Burning on Public Land in Victoria, ensuring that burning practices took full account of adverse impacts on wildlife, soils, and tree growth.

A key message from the 2003 report emphasized the importance of long-term monitoring, as short-term fire effects research can be misleading. The Wombat study was highlighted as one of the most important and successful long-term ecological studies in Eastern Australia, demonstrating the high resilience of the Wombat Forest to fire due to the patchiness and variability in fire characteristics, contrasting with the major ecological impacts of large, intense wildfires.

Legacy and Future Opportunities

The Wombat Fire Effects Study provides a unique opportunity to exploit the replicated design and long-term multidisciplinary information. However, full advantage has not yet been taken of these features. The continuation of treatments and monitoring increases the capacity to identify the impacts of repeated burning. There are few areas in Victoria where the detailed nature of the fire history is known over such a long period, making the Wombat study a critical resource for future research.

The study has already contributed significantly to forest management practices, including the use of ecological criteria for planned burning, the development of the T-H Fine Fuel Moisture Meter, and the importance of weather factors in post-fire responses. Future research could explore new variables such as greenhouse gas emissions, soil carbon change, and hollow dynamics, building on the established experimental design and known fire history.

Acknowledgments

In his 2003 Summary Report of the Wombat Study, Kevin noted in his Acknowledgements that "This research program was conceived by Dr Fred Craig, Chief of Education and Research, Forests Commission, Victoria and was developed with the assistance of Dr David Flinn, and later, Dr Kevin Tolhurst. The improved knowledge informing public land fire management in Victoria represents a tribute to the foresight of Fred and Dave". This inspired me to write this introductory article. Dr Thomas Baker contributed to finalizing the article, drawing from unpublished notes and a bibliography by Assoc Prof Kevin Tolhurst and Dr Richard Loyn.

Bibliography

See Also

Fuel Reduction Burning

In 1969, 1970 and 1974 the FCV, in conjunction with Monash University, organised symposiums related to fire ecology. The proceedings of each symposium are accessible below.