Fire management is a serious and truly complicated thing; the fuel that feeds fire is also our great natural heritage.
There will always be more to learn about fire behaviour and its management, especially as we live in a rapidly changing climate. Some common questions about protecting ourselves, our homes, and caring for our unique environment, are clarified here.
The impact of the bushfires on the physical, emotional and economic wellbeing of people and communities has been huge. Some have lost their life, many have lost houses, farm stock and infrastructure, and others have lost businesses and job opportunities. Healing, where it’s possible, will take time, resources, care and understanding.
Yes, it is, but the 2019–20 fires are unprecedented in their extent across the nation.
After the Australian landmass broke free from the ancient continent of Gondwana over 100 million years ago, an increase in fire actually drove the evolution of the typical Australian flora such as our eucalypts.
Our many different ecosystem types respond differently to the range of frequencies, times and severity of fire. Native grasslands generally like fairly frequent fire, whereas our pockets of rainforest, which are remnant survivors of the ancient Gondwanan forests, can’t handle fire at all. Our towering mountain and alpine ash trees are easily killed by fire, and if two fires happen about 10–15 years apart there has not been time for new trees to produce seed: the ash forest dies. But if a fire comes every hundred years or more to an ash forest, the regenerating forest has had plenty of time to develop seed, and also to develop important habitat structures like hollows.
Across Victoria’s 100 or more ecosystem types and the roughly 100,000 native species that depend on them, there is a great range of responses to fire frequency and severity. Victoria’s Flora and Fauna Guarantee Act 1988 has listed “Inappropriate fire regimes” as a Potentially Threatening Process (to the wellbeing of native species) since 2003, pointing out that “No one interval can be can be used as an acceptable time between fires for the maintenance of biodiversity across Victoria”.
The unprecedented scale of this summer’s fires will have a huge impact on the health of many of Victoria’s ecosystems, and on individual plants and animals, especially those with restricted distribution. Some, like Victoria’s highly threatened Brush-tailed Rock Wallaby, whose only secure habitat is in the upper Snowy River, may have been lost to us. And species that depend on tree hollows and abundant food, such as Greater Gliders and Sooty Owls, are now seriously compromised. Similarly, smaller mammals and reptiles that depend on hollow logs and woody debris will have less abundant habitat. Some native fish, especially those restricted to just one stream, will be impacted by the siltation of waterways. Many highly localised native plants, such as the uncommon arboreal Butterfly Orchid, may lose most of their habitat. Over 60% of state forests have been burnt in East Gippsland and the north-east, and over 30 Victorian parks and reserves have been 100% burnt, many others are significantly burnt. It is estimated around 50 native animal and 150 native plant species, many of them rare and threatened, are suffering severe loss of habitat.
A full assessment of the extent of the impacts will take time and need to include on-ground assessment.
What can be done to help recovery?
Early intervention is important. Moves are already afoot to establish on-ground assessments of impacts, to temporarily remove some species (especially aquatic species), to considerably boost feral predator control (such as foxes and cats) and for urgent feral herbivore control (especially deer, horses and pigs and goats). The recent fires have opened up the canopy, offering a rare chance for aerial control of many herbivores. Adequately resourcing these initiatives is critical, as the initial post-fire months are an uncommon opportunity for effective control of species like deer that and normally seek the cover of any undergrowth.
It will also be important, while the fires progress over the month or two ahead, to do our best to protect all currently unburnt patches, even the very small ones, as essential refuges for wildlife.
Climate scientists and ecologists have been predicting more frequent and more severe fires in Victoria for decades, and those predictions have been increasingly borne out in recent years. While one fire event can’t always be attributed to human-induced climate change (there have been severe fires in the 19th century), the extent of fire across eastern Australia in 2019–20 is unprecedented in living memory. Increasing temperatures and increasing drought events are clearly producing an increasing frequency of severe fire. The Victorian Government Commissioner for Environmental Sustainability has a detailed summary here.
Visit VicNature 2050 at vicnature2050.org for an outline many things you can do to help nature deal with climate impacts.
Fire management on public land, including in both national parks and timber harvesting areas, is controlled by Forest Fire Victoria, an arm of the state government’s Department of Environment, Land, Water and Planning (DELWP). Parks Victoria, the state government agency which manages our national parks and many other areas of public land, works with DELWP in the management and control of fire, but does not control levels of prescribed burning in national parks. For good reason, the prime concern for fire managers across all public land is the protection of human life.
According to Victoria’s Code of Practice for Bushfire Management on Public Land, which fire managers are obliged to follow, there are two primary objectives for fire management:
- To minimize the impact of major bushfires on human life, communities, essential and community infrastructure, industries, the economy and the environment. Human life will be afforded priority over all other considerations.
- To maintain or improve the resilience of natural ecosystems and their ability to deliver services such as biodiversity, water, carbon storage and forest products.
DELWP doesn’t have responsibility for fuel loads or fire management on private land, but efforts to align public and private land management are advancing under a new ‘Safer Together’ program.
Other organisations involved in bushfire management include:
- The Country Fire Authority (CFA), a largely volunteer organisation which assists in fire management, including fighting fires across the state. It generally has oversight of fuel reduction on smaller areas of land and many roadsides, along with local councils.
- Emergency Management Victoria (EMV) coordinates the operational responses from all agencies involved in emergencies in Victoria, including the development of risk management capability.
No, not at all. Large areas of fuel reduction burns are conducted in our national parks each year.
Since the Stretton Royal Commission into the 1939 Black Friday fires, fuel management across all public land has been handled by one state government department (originally the Forests Commission, now Department of Environment, Land, Water and Planning [DELWP]). Each year DELWP revises Fire Operation Plans (FOPs) across Victoria’s fire management regions for the next three years. All members of the public can have input into that planning process.
Parks Victoria (the state government agency that manages our national parks and many other areas of public land) also has input into that planning process, but final burn prescriptions in parks are decided by DELWP. Ecological burns also take place in some of our parks. The careful application of repeated fire at Wilsons Promontory National Park, for example, is currently being employed to restore the grassy woodlands of the Yanakie Isthmus. Elsewhere on the Prom, however, fire has been far too frequent in recent decades.
The general terms for any deliberately applied management burn include ‘prescribed burn’, ‘planned burn’ and ‘management burn’. Within that general category there are three specific types of burn:
- Fuel reduction burns. These are planned burns performed at safe times during the year, aimed at reducing the fuel load long before a bushfire starts.
- Ecological burns. These are burns performed under the advice of ecologists, aimed at maintaining the health of a particular species or ecosystem. (Sometimes ecological burns also act as fuel reduction burns, and vice versa, but not necessarily.)
- Back burns. Backburning is a strategy used when a bushfire is running beyond control. Under certain conditions it is possible to burn back towards a running fire, to immediately reduce fuel in its path. It can be a risky strategy, as sometimes these burns can add to the fire front, making a fire bigger.
What happened to Victoria’s ‘5% of public land’ annual fuel reduction target?
The Victorian Bushfires Royal Commission, set up after the 2009 Black Saturday fires, recommended burning at least 5% (around 390,000 hectares) of public land annually, but the Commission did not closely follow the advice of its own expert panel on fuel reduction. Most panel members had only agreed on setting a 5% minimum target as a trial in Victoria’s ‘foothill forests’, essentially our lower elevation stringybark forests. Panel members had also pointed out that setting a large area target could lead fire managers to burn the ‘low hanging fruit’, the remote places where large areas could most easily be burnt with little risk to people or infrastructure. That turned out to be the case, with large burns being conducted in the Mallee where they were causing considerable ecological harm without significant public safety benefits. A 2015 review of the 5% target recommended it be replaced by a risk-based target, encouraging planned burns to take place where they are most likely to be effective in protecting life and property, based on evidence.
How often has Victoria achieved a planned burn total of 5% of public land?
There has only been one year, 1980–81, when Victoria’s land management agency achieved planned burns across 5% of our public land. However the practice at that time largely consisted of burning ridge-tops to protect adjoining timber harvesting operations. The entire area, not just the ridge-tops, was then counted as the burn area. As our forests dry, and the weather warms, it becomes increasingly hard to safely achieve large areas of planned burns.
How and where should we plan to burn each year?
Fire scientists who have looked at fuel reduction programs in south eastern Australia in recent years have published a number of peer-reviewed papers that seriously challenge the effectiveness of current programs. Notable evidence-based observations include:
- Broad-scale fuel reduction can assist control of a fire in mild weather, but in extreme fire danger days, when most lives are lost, fuel reduction has had little capacity to lessen the progress or severity of a fire.
- Fuel reduction is most effective when it has occurred close to the asset in need of protection, especially in extreme fire danger weather. Fuel reduction close to buildings is difficult and expensive to conduct safely, however, and contributes little to a large hectare ‘target’. Also, areas closest to assets may be on private land, where government agencies currently have less control. The recent development of the ‘Safer Together’ program is trying to address co-ordination of fire management planning across private and public land.
- There is a growing body of evidence that in many forest types a fuel reduction burn only reduces ground fuel for a small period, often just a few years, before it actually has the opposite effect of increasing fuel by stimulating shrub growth. Long-unburnt areas can have far less fuel than recently burnt areas. Unfortunately, we now have very few long-unburnt areas in the state.
- There is also growing evidence that frequently repeated fire can actually promote the growth of our more flammable shrubs – the ones that have evolved to respond well to frequent fire.
Programs working with Traditional Owner groups are increasingly being introduced by DELWP and Parks Victoria. We should learn whatever we can from the historical burning practices of Aboriginal communities, and from their concern for and care of Country. Some of that understanding might include:
- Aboriginal people, before and shortly after European occupation of Victoria, applied fire for a range of purposes, in different seasons in a range of ecosystem types. They didn’t uniformly burn large areas across the landscape for one single reason. Generally their burns were smaller, cooler and controllable.
- They understood a lot about how each ecosystem type, and how individual food or resource plants, responded to certain types of fire at particular times. With Traditional Owners, we need to build that level of understanding of local ecosystems.
Some issues we must also consider include:
- The appalling treatment of Aboriginal communities since European occupation has led to a loss of some of the depth of knowledge about managing Country.
- While there is abundant evidence that pre-European Victoria had large areas of open grasslands, and also woodlands with a grassy understory, most of that land is now farmland.
- The last two hundred years have greatly altered the landscape, especially through habitat fragmentation, timber harvesting and invasions by a large range of pest plants and animals.
- Climate change has introduced a significant, and very difficult, complication into the management of fire and our natural areas. What used to work won’t always apply now.
Discover more about Indigenous cultural fire here.
There is abundant evidence that logging native forests over the last 150 years or more has resulted in younger and drier forests in much of Victoria. Claims by the forest industry that ‘thinning’ our forests, or more logging, will reduce bushfires can't be sustained. Opening up the forest canopy dries the forest floor, and further reduces the abundance of ferns and other moisture loving plants. The Andrews Government has planned to end logging of native forests by 2030; we should have transitioned to plantation forestry long ago.
Scientific studies have clearly shown that alpine grazing does not reduce fire. This is largely because cattle don’t eat shrubs, which are the main vehicle for the spread of fire in the high country.
Yes. Slashing grasses and undergrowth can be an effective way of reducing fuel loads close to assets, particularly when fuel reduction burns in those areas can’t be conducted safely. This is a significant issue on private land, but also an issue on public land immediately adjoining infrastructure such as houses, fences etc. that may be impacted by a management burn. However, slashing can sometimes have adverse environmental impacts that should be considered.
Yes, many. Neil Comrie, who was responsible for monitoring implementation of the 2009 Victorian Bushfires Royal Commission recommendations, pointed out that fuel reduction was just one fire management tool, and it should be taken into consideration along with all other options. Yet still, unfortunately, fuel reduction programs are the only aspect of fire planning and control that routinely invite public input. Other important management tools include:
- Aerial attack at ignition points. If aircraft can get to an ignition point within 10–15 minutes of notification, there is a very good chance of stopping a fire in its tracks. Due to a steady build-up of aerial capacity in Victoria, we now have the ability to get aircraft to areas near Melbourne within that time, critical for highly vulnerable and densely populated areas like the Dandenongs, Warrandyte and the Mornington Peninsula. Deploying a similar capacity around the state would be expensive, and won’t stop every fire, but could stop some. It’s worth noting that Black Saturday alone cost Victoria many lives and over $4 billion.
- Dealing realistically with arson. Recent research shows that arson is primarily a sociological problem, and could be reduced through employment and other support programs in disadvantaged urban fringe and rural communities – something that should happen anyway.
- Private bushfire bunkers to the approved standard should be made compulsory for any new buildings in fire-prone areas, and strongly encouraged for existing homes etc. The development of an approved standard design for shelters was an early recommendation of the 2009 Royal Commission, but little or nothing has been done to encourage or facilitate their use.
- Compulsory evacuation. Both the USA and Canada have laws facilitating compulsory evacuation in face of a fire threat, and they have proved very successful in saving lives. That power should be given to Victoria’s fire managers, and regional strategies for evacuation developed well in advance of a fire occurring. The right to ‘stay and defend’ should only be given to householders who are fit, are well-prepared and have a well-designed bunker.
Discover more about how we can better integrate all fire strategies in the Park Watch September 2017 magazine pages 21-23.
Peer reviewed scientific studies are critical to any improvement in fire management. There have been many research papers published in the last decade that provide evidence-based suggestions for ways in which we can improve our management of fire. The research papers quoted below are all peer-reviewed Australian papers published in established scientific journals or, in a few cases, papers/publications published by DELWP. They have been authored by well-established fire behaviour experts and fire ecologists, and for the most part relate specifically to south-eastern Australia. Together, they indicate the need for significant reform in fire management in Victoria.
Papers indicating the relative effectiveness/ineffectiveness of fuel reduction for protection of the public:
Many research papers have questioned the efficacy of large-scale fuel reduction burns. There is clear evidence that fire managers should be focused on dealing with the impacts of extreme fire weather, if the over-riding objective of fire management – saving lives – is to be substantially achieved.
“The fatalities from Australia’s 10 worst bushfire days accounted for 64% of all civilian fatalities. Over 50% of all fatalities occurred on days where the McArthur Forest Fire Danger Index (FFDI) exceeded 100 (the current threshold for declaring a day as ‘catastrophic’) proximal to the fatality.” … “Fatalities were dominated by a few bushfires that have occurred under catastrophic weather conditions. These conditions should be used as the context for discussing appropriate defensive actions for communities faced with a bushfire threat.”
Blanchi R, Leonard J, Haynes K, Opie K, James M, Dimer de Oliveira F. (2014) Environmental circumstances surrounding bushfire fatalities in Australia 1901–2011. Environmental Science & Policy 37 (2014) 192-203
One of the most consistent findings of research projects is that the effectiveness of any fuel reduction program is reduced considerably under severe fire weather conditions. (To our knowledge, this has not been publicly acknowledged by DELWP.)
“An increase in fuel treatment, such as prescribed burning, may reduce crown fire risk but it has also been shown that fire severity in these fires was not reduced by recent burning (reduced fuel) under very severe weather .”
Price O, Bradstock R. (2013). Landscape scale influences of forest area and housing density on house loss in the 2009 Victorian Bushfires. PLoS One, 8 (8), e73421-1-e73421-6
A 2012 paper looked specifically at evidence from Victoria’s Black Saturday fires in this respect:
“The results suggest that recently burnt areas (up to 5–10 years) may reduce the intensity of the fire but not sufficiently to increase the chance of effective suppression under severe weather conditions. Since house loss was most likely under these conditions (67%), effects of prescribed burning across landscapes on house loss are likely to be small when weather conditions are severe. Fuel treatments need to be located close to houses in order to effectively mitigate risk of loss.”
Price O, Bradstock R. (2012) The efficacy of fuel treatment in mitigating property loss during wildfires: Insights from analysis of the severity of the catastrophic fires in 2009 in Victoria, Australia. Journal of Environmental Management, Volume 113, 30 December 2012, Pages 146-157
Other papers have pointed out that fuel reduction burns are only effective in reducing fuel loads for a few years at most.
“The influence of prescribed burning on subsequent fire behaviour diminishes within 2 to 10 years.”
Wilson N, Cary G and Gibbons P. (2018) Relationships between mature trees and fire fuel hazard in Australian forest. International Journal of Wildland Fire 2018, 27, 353–362
Importantly, fuel levels in many ecosystems are known to actually increase just a few years after a fuel reduction burn. (As far as we are aware, DELWP does not systematically monitor the stages of regeneration of understory vegetation/fuel load following management burns.)
“Overall fuel hazard was higher in forests and woodlands burned 6–12 years previously than those unburned for at least 96 years” and “Frequent burning can maintain forest understorey in an early successional ‘shrubby’ state, leading to higher overall fuel hazard than forests where a lack of fire is associated with the senescence of shrubs.”
Dixon K, Cary G, Worboys G, Seddon J and Gibbons P. (2018) A comparison of fuel hazard in recently burned and long-unburned forests and woodlands. International Journal of Wildland Fire. July 2018
Other papers have indicated not only that the understory regenerates soon after a fuel reduction burn, but that attention should be given to the relative flammability of the species that first recolonize the burnt landscape.
“Apart from low, dry open woodland where there was insufficient data to detect a trend, all forests were most likely to experience crown fire during their period of regeneration. The implications of this are significant for the Alps, as increasing fire frequency has the potential to accelerate by producing an increasingly flammable landscape” and “Across the Australian Alps, recently burnt forests have been on average more flammable than mature forests, consistent with historic observation and the mechanistic understanding arising from plant growth and species’ change.”
Zylstra P. (2018) Flammability dynamics in the Australian Alps. Austral Ecology (2018)
As far as we are aware, DELWP’s monitoring and/or risk modelling does not take into account the relative flammability of different understory species. A paper co-authored by eight well-recognised south eastern Australian fire behavior scientists and fire ecologists has drawn attention to the importance of avoiding simplistic fuel flammability models.
“Our study found that for these sites, plant traits were more important for predicting flame height than was surface fuel load.” … “Conventional approaches to modelling fire behaviour based on the mass of surface litter and simple measures of above-ground fuel strata may therefore be unable to predict aspects of fire behaviour that arise from variations in forest composition.”
Zylstra P, Bradstock RA, Bedward M, Penman TD, Doherty MD, Weber RO, Gill AM, Carey GJ. (2016). Biophysical Mechanistic Modelling Quantifies the Effects of Plant Traits on Fire Severity: Species, Not Surface Fuel Loads, Determine Flame Dimensions in Eucalypt Forests. PLoS ONE 11(8): e0160715. doi:10.1371/journal.pone.0160715
Many papers have concluded that fuel reduction close to assets in need of protection, while it may be the most difficult to achieve, is the most effective – and the most cost-effective.
“Results of this study demonstrate that treatment of fuels at the interface [ie close to buildings] is not only the best means of reducing risk, it is also the most cost-effective.”
Penman T, Bradstock R, Price O. (2013) Reducing wildfire risk to urban developments: Simulation of cost-effective fuel treatment solutions in south eastern Australia. Environmental Modelling & Software 52 (2014) 166e175
“All fuel treatments were more effective if undertaken closer to houses. For example, 15% fewer houses were destroyed if prescribed burning occurred at the observed minimum distance from houses (0.5 km) rather than the observed mean distance from houses (8.5 km). Our results imply that a shift in emphasis away from broad-scale fuel-reduction to intensive fuel treatments close to property will more effectively mitigate impacts from wildfires on peri-urban communities.”
Gibbons P, van Bommel L, Gill AM, Cary GJ, Driscoll DA, et al. (2012) Land Management Practices Associated with House Loss in Wildfires. PLoS ONE 7(1): e29212. doi:10.1371/journal.pone.0029212
A Tasmanian study re-enforced the need for burns close to assets, and acknowledged difficulty of achieving an effective level of broad-scale fuel reduction burning.
“The study highlights that prescribed burning can theoretically mitigate wildfire, but that an unrealistically large area would need to be treated to affect fire behaviour across the island [Tasmania]. Rather, optimisation of prescribed burning requires careful landscape design at the local scale.”… “intensive, localised prescribed burning plans could be used for protecting assets or targeting areas of high risk.” … “In conclusion, our simulation study has shown that realistic, implementable prescribed-burning plans to reduce fine fuel loads in fire prone Tasmanian grasslands, sedgelands and dry eucalypt forests have little potential to substantially reduce the extent and intensity of wildfires at a state-wide scale.”
Furlaud J, Williamson G, and Bowman D. (2007) Simulating the effectiveness of prescribed burning at altering wildfire behaviour in Tasmania, Australia. International Journal of Wildland Fire
And a NSW study agrees.
“In extreme weather, even 1-year-old patches have a low likelihood of stopping unplanned fires. Fuel age had little influence on the spread of unplanned fires. Consequently, prescribed fires will be most effective when sited at the urban interface where resultant reduced unplanned fire intensity will be a benefit.” … “Some studies from forests in south-eastern Australia report that fine fuels are back to significant levels (i.e. likely to lead to fire intensities that are unsuppressible) after between 3 and 5 years (Conroy 1996; Adams and Simmons 1995; Morrison et al 1996; Annon 2003; Gould et al 2007). The present study suggests that the modest effect of fuel reduction on ability to stop a subsequent unplanned fire is essentially gone after 5 years.” … “Under extreme weather conditions, unplanned fires may not be controllable unless they have been recently burnt (Grant and Wouters 1993). Thus it is sensible to place prescribed burns in areas where maximum advantage can be gained from suppression of subsequent unplanned fires: that is, primarily close to the assetts that need to be protected.”
Price O, and Bradstock R. (2010) The effect of fuel age on the spread of fire in sclerophyll forest in the Sydney region of Australia. International Journal of Wildland Fire 19(1) 35-45; doi.org/10.1071/WF08167
Others have pointed out that, in any realistic scenario of broadscale fuel reduction, those areas that have been very recently burnt are relatively unlikely to encounter an unplanned fire.
“In all bioregions, weather was a stronger predictor than past-fire extent of area burnt in a particular year.” … “… fuel management strategies applied in one region are not necessarily applicable in another. In most bioregions prescribed burning is likely to have very little effect on subsequent extent of unplanned fire, and even in regions where leverage occurs, large areas of treatment are required to substantially reduce the area burned by unplanned fire.” … “A recently burnt patch may slow or stop an unplanned fire should one occur, but low encounter rates make this unlikely. The most efficient use of prescribed fire is applying it to the immediate proximity of assets, where a resultant reduction in fire intensity can be of immediate benefit in terms of impacts on structures and ease of suppression (Price & Bradstock, 2010, 2012).”
Price O, Penman T, Bradstock R, Boer M and Clarke H. (2012) Biogeographical variation in the potential effectiveness of prescribed fire in south-eastern Australia. Journal of Biogeography (J. Biogeogr.) (2015) 42, 2234–2245
Studies have highlighted the need to assess the effectiveness of fuel reduction programs against other fire management tools. A number of papers point out that an increased emphasis on ignition management (i.e. aerial attack capability, powerline management, fire bug vigilance etc.) should be receiving attention in fire management policy and planning.
“The findings demonstrate that year-to-year variation in weather and the success of ignition management consistently prevail over the effects of fuel management on area burned in a range of modelled ecosystems.” … “Weather and ignition management effort were more important than fuel management approach and effort in determining total area burned in five landscape fire models. Modelled area burned decreased with increasing levels of ignition management effort in all models. Increasing effort in a random fuel reduction approach resulted in decreased areas burned in the model systems but the effects were unimportant compared with that of varying weather and level of ignition management.”
Cary, G. J., Flannigan, M. D., Keane, R. E., Bradstock, R. A., Davies, I. D., Lenihan, J. M., Li, C., Logan, K. A. & Parsons, R. A. (2009). Relative importance of fuel management, ignition management and weather for area burned: evidence from five landscape-fire succession models. International Journal of Wildland Fire, 18 (2), 147-156
“Despite policy imperatives to expand fuel treatment, a reduction rather than an elimination of risk will result. Multifaceted strategies will therefore be required for the management of risk.” … “Feasible fuel treatment strategies are likely to leave considerable residual risk in many Australian forested ecosystems and this risk may be expected to increase in the future. Explicit recognition of this fundamental conclusion and its attendant consequences, including costs, will be needed to build a more comprehensive approach to the management of risks to people and their infrastructure.”
Bradstock R, Cary G, Davies I, Lindenmayer D, Price O, Williams R. (2012) Wildfires, fuel treatment and risk mitigation in Australian eucalypt forests: Insights from landscape-scale simulation. Journal of Environmental Management 105 (2012) 66e7
A number of papers have looked at the relative ineffectiveness of alpine cattle grazing in reducing the extent of fire in the high country.
“Whatever effects livestock grazing may have on vegetation cover, and therefore fuels in the alpine landscapes, they are likely to be highly localised, with such effects unlikely to translate to into landscape-scale reduction of fire occurrence or severity. The use of livestock grazing in Australian alpine environments as a fire abatement practice is not justified on scientific grounds.”
Williams R, Wahren, CH, Bradstock R, Muller W. (2006) Does alpine grazing reduce blazing? A landscape test of a widely-held hypothesis. Austral Ecology (2006) 31, 925-936.
Papers indicating impacts of fire and/or fire management on biodiversity:
A recent 2018 paper looking at the causes of endangered species Australia-wide, lists inappropriate fire regimes as one of the most significant impacts on these species.
“Since European occupation, many areas have experienced dramatic changes in fire regime, ranging from reductions in the incidence of fire to increases in the frequency, extent and intensity of fire.” … We highlight that if Australia is to conserve its globally significant biodiversity, a better-planned response supported by adequate funding and effective policy and legislation is urgently needed.”
Kearney SG, Cawardine J, Reside A, Fisher D, Maron M, Doherty T, Legge S, Silcock J, Woinarski J, Garnett S, Wintle B and Watson J (2018) The threats to Australia’s imperilled species and implications for a national conservation response. Pacific Conservation Biology. CSIRO; doi.org/10.1071/PC18024
It is difficult to replicate pre-European Aboriginal burning, (and questionable whether those fire regimes would always be appropriate now, given issues with invasive species and a changing climate etc.). However recent approaches to re-establish Indigenous fire, such as applying ‘The right fire, at the right time, in the right way, for the right reasons’ seem very sensible guidelines.
The impacts of planned and/or unplanned fire on Victoria’s biodiversity are understandably complex, with around 100,000 different native species occupying some 300 different recognized Ecological Vegetation Communities (EVCs). It has been generally accepted that, for any given EVC or habitat type, establishing a range of fire age classes (or time since fire) allows for a good range of different species’ habitat requirements. However increased fire in the landscape (both bushfires and planned burns) over recent years has resulted in a significant depletion of older age classes, and these are very hard to re-establish once lost. As DELWP fire ecologist David Cheal pointed out in 2010, in a page of caveats to his extensive report on suitable growth stages for different habitat types:
“Early growth stages can be created far more easily than can late (mature) stages. Recently burnt vegetation can be created in a single season. Some important habitat features occur only in mature to senescent vegetation and thus take decades, or even centuries, to develop.”
Cheal D (2010) Growth stages and tolerable fire intervals for Victoria’s native vegetation data sets. Fire and adaptive management report no. 84. DELWP 2010
A number of papers have been published recognizing the importance of protecting long-unburnt (or near long-unburnt) vegetation.
“For example, the long-unburned sites in our study area are disproportionately more important for reptile and mammal richness and abundance than those with a shorter time-since-fire” and “Regardless what management action is applied for reducing overall fuel hazard, our results suggest that long-unburned forests should be protected from fire”.
Dixon K, Cary G, Worboys G, Seddon J and Gibbons P. (2018) A comparison of fuel hazard in recently burned and long-unburned forests and woodlands. International Journal of Wildland Fire. July 2018
“Additionally, prescribed burns carry significant side effects, such as ecological harms, both through degrading faunal habitat (Catling et al. 2001; Andersen et al. 2005) and disadvantaging some plant species that require long fire-free intervals to complete their life cycle.”
Furlaud J, Williamson G, and Bowman D. (2017) Simulating the effectiveness of prescribed burning at altering wildfire behaviour in Tasmania, Australia. International Journal of Wildland Fire
“Our review reiterates the vulnerability of ‘fire sensitive’ obligate seeder forests, but also highlights similar threats to ‘fire tolerant’ resprouter forests posed by multiple recurrent wildfires of high severity.” … “Our review highlights that even in forest types well adapted to fire the consequences of increasing wildfire frequency are worth renewed and directed attention.”
Fairman T, Nitschke C and Bennett L. 2015) Too much, too soon? A review of the effects of increasing wildfire frequency on tree mortality and regeneration in temperate eucalypt forests. International Journal of Wildland Fire. 14 September 2015
“There is little evidence for any ecological benefit from the planned burns, at least in the short term. … In contrast, there is evidence that burning results in depletion of habitat resources for a range of faunal species.” … “Given the commitment to increased levels of burning on public land annually, it is critical to undertake strategic planning to develop a vision and target for the post-fire, age-class structure of these forests. … A high priority is to determine those areas to be maintained as the ‘long unburnt’ growth stage.”
Holland G, Bennett A, Clarke M and others (2015) Box-Ironbark Experimental Mosaic Burning Project. Report to the Department of Environment. Land, Water and Planning and Parks Victoria, 2015
And a paper assessing claims of biodiversity impacts after the 2003 alpine fire in Victoria and NSW pointed out that frequent fire in that landscape was historically uncommon. Frequent fire, rather than severe fire after long intervals, was more likely to adversely impact alpine plants and animals.
“We conclude that infrequent extensive fires are a feature of alpine Australia. For both the flora and the fauna, there is no quantitative evidence that the 2003 fires were an ecological disaster, and we conclude that the flora and the fauna of alpine Australia are highly resilient to infrequent, large, intense fires.”
Williams R, Wahren CH, Tolsma A, Sanecki G, Papst W, Myers B, McDougall K , Heinze D and Green K. (2008) Large fires in Australian alpine landscapes: their part in the historical fire regime and their impacts on alpine biodiversity. International Journal of Wildland Fire 17(6) 793-808; doi.org/10.1071/WF07154
Many studies have recognized the importance of maintaining or improving the presence of a large range of tree hollows in the landscape. Notably, frequent fire can adversely affect these important structural components of forests and woodlands.
“Charring effects on hollow formation, increasing hollow size but decreasing overall hollow presence, demonstrates the complex effect of fire on this resource.”
Stares M, Collins L, Law B and French K. 2018) Long-Term Effect of Prescribed Burning Regimes and Logging on Coarse Woody Debris in South-Eastern Australia. Forests 2018, 9, 242; doi:10.3390/f9050242
The presence of hollow logs on the ground is a critical habitat feature for many species, and can take a very long time to become re-established.
“Longer-term impacts of prescribed burning will be strongly influenced by the return interval, given the slow rate at which some structural components accumulate (decades to centuries)” and “Replacement of components such as large logs, first requiring older trees with large trunks/limbs, potentially requires a century or more … A key point is that, despite being relatively mild and patchy, prescribed burns may continue to influence forest structure for more than a century into the future.”
[This is important, given that]
“More than 150 years of European settlement and diverse land use has left the box-ironbark forests of southeast Australia in a highly disturbed and simplified state, with structural components such as large logs and deep litter layers being extremely scarce (ECC 1997).”
Holland G, Clarke M, and Bennett A. (2017) Prescribed burning consumes key forest structural components: implications for landscape heterogeneity. Ecological Applications, 27(3), 2017, pp. 845–858
“Our work highlights the need for management of fire regimes to be complemented by an understanding of the underlying environmental gradients and key elements of habitat structure that influence resource availability for plants and animals.” … “Time since fire influenced vertebrates, particularly bird abundance, more than plants. Of species that responded to time since fire, most were associated with older fire ages (e.g., rose robin, golden whistler, yellow-faced honeyeater).” … “Fire type, a surrogate for fire severity, had a relatively minor influence at the long temporal scales and large spatial scales of this study. In particular, there is a need for data and analytical approaches that can provide guidance on the fire responses of rarer or more cryptic species, often those of greatest conservation concern.”
Kelly, L. T., A. Haslem, G. J. Holland, S. W. J. Leonard, J. MacHunter, M. Bassett, A. F. Bennett, M. J. Bruce, E. K. Chia, F. J. Christie, M. F. Clarke, J. Di Stefano, R. Loyn, M. A. McCarthy, A. Pung, N. Robinson, H. Sitters, M. Swan, and A. York. (2017). Fire regimes and environmental gradients shape vertebrate and plant distributions in temperate eucalypt forests. Ecosphere 8(4):e01781. 10.1002/ecs2.1781
One study, published by DELWP, specifically associated fuel reduction programs with hollow loss.
“Tree hollows are a key habitat component for some 300 Australian vertebrate fauna species, of which a third have formal conservation status (Gibbons and Lindenmayer 2002).” .… “This study has demonstrated that planned burns in Gippsland increase the collapse risk of HBTs [hollow-bearing trees] significantly and, by implication, are likely to cause loss of habitat for hollow-dependent fauna in areas where hollows are needed.”
Bluff L. (2016) Reducing the effect of planned burns on hollow-bearing trees. Victorian Government Department of Environment, Land, Water and Planning, Melbourne, February 2016
Another DELWP study highlighted the importance of a broad range of age classes.
“For birds the strongest relationships related to fire frequency, with nectarivores responding negatively to frequent fires, and two other guilds showing weaker positive responses. Ground nesting birds were scarce at sites that had been burnt below the minimum Tolerable Fire Interval.” .. “The study examined a subset of the biota and so a precautionary approach is warranted to fire planning and implementation, taking account of other studies and future work dealing with groups such as lichens, fungi, owls, arboreal mammals, microbats and invertebrates.” … “Frequent burning will benefit some plant and bird groups and disadvantage others (and probably also mammals). Hence it is important to continue generating a mix of fire regimes across the landscape, and a mix of age-classes.”
Muir A, MacHunter J, Bruce M, Moloney P, Kyle G, Stamation K, Bluf L, Macak P, Liu C, Sutte Gr, Cheal D and Loyn R. (2015). Effects of fire regimes on terrestrial biodiversity in Gippsland, Victoria: a retrospective approach. Arthur Rylah Institute for Environmental Research, DELWP 2015
A series of studies over many years has looked at the essential habitat structure of Victoria’s Ash forests. According to one of these papers:
“Large trees with cavities provide critical ecological functions in forests worldwide, including vital nesting and denning resources for many species.” … This large cavity tree crisis in Mountain Ash forests is a product of: (1) the prolonged time required ([greater than] 120 years) for initiation of cavities; and (2) repeated past wildfires and widespread logging operations.” … “Significant negative ecological consequences will arise from the Mountain Ash-wide absence of large cavity trees [including] impaired key ecosystem processes like the recruitment of large logs to the forest floor [7,89]. In the particular case of Mountain Ash forests, a paucity of large-diameter dead trees will deplete the nesting and denning resources required by, ~ 40 species of cavity-dependent vertebrates in these ecosystems.”
Lindenmayer DB, Blanchard W, McBurney L, Blair D, Banks S, Likens GE, et al. (2012) Interacting Factors Driving a Major Loss of Large Trees with Cavities in a Forest Ecosystem. PLoS ONE 7(10): e41864 doi.org/10.1371/journal.pone.0041864
And other studies essentially agree with the need to protect long-unburnt habitat.
“All species remained in the broad landscape, and most were found on at least some sites that had been burnt and were far from suitable refuge sites. Nevertheless, it is likely that unburnt forest has contributed substantially to the survival and persistence of these species in the landscape.”
McNabb E, Cheers G & Loyn R. (2012) Persistence of owls and arboreal mammals after severe wildfire in the Goulburn Broken catchment. Arthur Rylah Institute for Environmental Research, March 2012
“Our results point to an urgent need for comprehensively designed studies to address the impacts of prescribed burns on hollow-bearing trees.” … “We conclude that low intensity prescription burns may cause levels of destruction of hollow-bearing trees that are substantial enough to warrant immediate attention from managers.”
Parnaby H, Lunney D, Shannon I and Fleming M. (2010) Collapse rates of hollow-bearing trees following low intensity prescription burns in the Pilliga forests, New South Wales. Pacific Conservation Biology 16(3) 209 – 220
A well-researched book, The Victorian Bush: its 'original and natural' condition by Ron Hately, published in 2010, has looked at early colonial records to try and establish the pre-European nature of the Victorian bush. It points out that while large areas were clearly grasslands and open grassy woodlands, other areas were forests with thick understory.