To burn or not to burn?

This article first appeared in the March-April 2015 edition of Wildfire. By Dr Richard Thornton, CEO of the Bushfire and Natural Hazards CRC.

Australia has a long and continuing history of burning in its forests to reduce fuels and maintain biodiversity. However, the debate over prescribed burning targets has been an ongoing one for almost as long as the practice has been conducted, with parties on all sides of the debate quoting evidence both for more burning or less burning.

In more recent years the calls by both sides of the discussion have become louder and more polarised. Meanwhile, the complexity of the issue has actually grown. The number of people and businesses have grown in and around the previously empty forested regions; the impact of smoke is an issue; the management water catchments is important; there is now more scientific evidence on the benefits and downsides of various fire regimes; and the windows for undertaking prescribed burning have shrunk due to drought and climate change.

There is no universal ‘right’ level of prescribed fire because there are competing objectives to be considered, vastly differing ecosystems to be covered, and constantly shifting variables in demographics and land use.

And even if you get all the objectives lined up you are still at the mercy of a fickle Australian weather system – too dry can be too dangerous to burn, too wet and little will burn.

And overlaying all of this are successive changes in governments at the local, state and national level – all with differing positions and varied appetites for land management policy. The list of public inquiries into these matters is long and goes back decades.

In August 2010, a national Inquiry by the Australian Senate described itself in its final report as the nineteenth major bushfire-related Inquiry to be conducted in Australia since 1939, and the third to be conducted federally since 2003. In evidence to the 2010 Inquiry Professor Peter Kanowski from the Australian National University (himself an author of the first national Inquiry in 2004) said that his Inquiry had identified...

‘….a repeated cycle of response by governments and the community to major fire events: first, suppression and recovery processes are always accompanied by assertions, accusations and allocations of blame, even while the fires are still burning; second, inquiries are established and report; third, recommendations are acted upon, to varying degrees; fourth, the passage of time sees growing complacency and reduced levels of preparedness... and the cycle begins again with the next major bushfire event….’

Following the devastating Black Saturday fires in Victoria in February 2009, the subsequent Royal Commission conducted the most comprehensive consideration of prescribed burning in southern Australia with a panel of scientific experts. Despite the members of this panel having a history of a range of views on fuel reduction, the panel achieved a rare consensus on the need for more prescribed burning. An agreed burning target of 5% was only to apply in the foothill forests.

However, the final report of the Royal Commission recommended that Victoria commit to burning a rolling annual target of 5% across all public land – more on that later. Although this was a recommendation that was put only to the Victorian Government most other states are also considering it as a target. 

After some particularly large and destructive fires in the karri and jarrah forests of Western Australia this past summer Senator Christopher Back rose in the Australian Parliament in February to state the logic in dramatically increasing the amount of hazard reduction burning:

The frustration comes due to the fact that we all know about the fire triangle. We all know that the three elements of bushfire and fire of any type are fuel, oxygen and a source of ignition. We know that lightning and humans are the main two causes—if not all causes—of ignition. We know we cannot do much about oxygen. Yet, we are continually confronted with this debate about fuel reduction. You cannot have a fire if you have not got the fuel.

The Senator’s sentiments are not universally accepted in Australia. With many prescribed burns now conducted close to the expanding urban fringe neighbourhoods and close to essential infrastructure and agriculture, the community tolerance levels are very low to heavy smoke and potential damage to delicate ecosystems. This has not been help by some significant escapes of prescribed burns which have caused extensive loss of houses and placed lives at risk. In particular an escaped prescribed burn near Margaret River in SW Western Australia in 2011 led to a complete ban on burning close to townships and caused the land management agency to completely rewrite its risk management processes. 

Risk reduction

Setting a target, however, is not an end in itself. Australian ecosystems have evolved to need some level of fire, but the return and intensity level varies dramatically depending on the type of ecosystem.

Importantly, fire is applied to various ecosystems for other reasons than just fuel reduction. This may include the preservation of ecosystem values such as biodiversity, water yield, soil preservation and other objectives. As noted in the 2012 Victorian Code of Practice for Bushfire Management on Public Land:

There are two primary objectives for bushfire management on public land:

• To minimise 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.

It would seem sensible to link the level of hazard reduction to the level of risk reduction of individual communities rather than just an arbitrary area-burnt target that is not linked to a prioritised objective.  Without objective-based measures there is no answer to the question about what is the right amount of land to treat.

Having prioritised risk-based measures will enable the Government to weigh up various treatment options across multiple hazards. The alternative is to consider prescribed burning in isolation of all other options, which may result in perverse outcomes such as spending money chasing artificial targets for a minimal reduction in risk to the assets being protected. For example it may be better to focus on achieving fuel reduction around townships and key assets, rather than burning large remote areas. Although the area burnt will be much smaller in the former and the cost higher, the reduction of risk is higher. This, of course, will not aid the chasing of hectares-burnt totals.

Targets for hectares burnt each year do have some merit in providing tangible measures against which government departments can set budgets and measure accountabilities. But the targets should be tempered with a measure of how many houses and assets were actually protected.

Cross tenure issues

The 2009 Victorian Bushfires Royal Commission had a focus on the role that fuel levels on public land (mainly national parks and state forests) played on the fires of Black Saturday. It was almost entirely silent on the role of fuels on private land, despite the fact that most deaths and damage to private assets resulted from the fires traveling over private land.

It would be wrong to assume that by setting targets only for public land that all the risks to people and property can be resolved. The idea that people should not consider the fuel levels on their own property and risk that it poses to themselves and others is inconsistent with the arguments and scientific evidence about the important role of fuels within 100 metres of properties and inconsistent with all notions of a “shared responsibility” when it comes to land management. Resident responsibility for their own land cannot be ignored simply because the government is treating the public land.

Of course, this responsibility is well accepted by many Australian landowners; many who vehemently berate local authorities for not respecting their side of the agreement with effective land management practices or not allowing targeted fuel reduction. This is also underpinned by council regulations, community messaging and enforcement. However, how to undertake prescribed burning on smaller properties remains a challenge, as well as the impacts of smoke from burns on community amenity and business operations, in particular the wine industry across Australia.

Local regulators and fire agencies understand that bushfires do not respect tenure boundaries and nor should a risk based consideration of community protection. It is important that the risk-based targets recognise the multiple players in land-management, and that the government alone should not be solely responsible for the risk treatments. 

Limits to burn targets

The Bushfire and Natural Hazards CRC and its predecessor the Bushfire CRC as well as many other Australian research organisations have accumulated decades of research into the bushfire hazards faced by Australian communities. Much research has been conducted on prescribed burning that includes a cost-benefit analysis of the risk, the economics of burning, the environmental impacts across varied types of landscapes, and the acceptance of prescribed burning by rural and interface communities.

It is important that whatever burning targets are in place are based on the best available evidence and scientific research. They should be measurable, achievable and articulated in such a way that the community can understand their residual risk.

And this residual risk must be accepted by the community and by governments - no hazard reduction target will reduce the risk to zero.

Fuel reduction can decrease fire intensity, flame height and the forward rate of spread. But the effectiveness of this reduction is strongly dependent on the weather conditions that prevail on the day they are impacted by a wildfire. On extreme high- temperature and high-wind days like Black Saturday, the effectiveness of most prescribed burning on stopping runs of large fires will be minimal because medium and long range spotting will see these areas overrun.

However, the fuel levels around properties and communities can make a significant difference to the intensity of the fire as it impacts private and public assets.

Meanwhile, as the debate still rages and inquiries continue in Australia over the merits and timing of prescribed burning, many local land management authorities are just getting on with the job - and dealing with the equal mix of complaints and praise on a daily basis.

In March in Victoria, as yet another government inquiry into prescribed burning – this one by the Inspector General for Emergency Management - closed its call for public submissions, the local land management agency was taking advantage of the mild temperatures and slight winds to reduce the fuel loads. As it communicated the risks on social media platforms, community reaction was a predictable mix of praise and scorn:

So who is monitoring the air pollution? Lots of people of Warburton are leaving for the day due to serious smoke exposure

Burns my eyes and gives me a sore throat when burn offs are done near my home.

(Posts to Facebook page of Department of Environment, Land, Water and Planning)