Modern Australian

controlled burns often fail to slow a bushfire

  • Written by Trent Penman, Associate professor, University of Melbourne

As sure as night follows day, this week’s bushfires prompted inevitable debate about whether fire authorities should have carried out more hazard reduction burning, and whether opposition from conservationists prevented this.

There are two key points to remember when we consider these questions. First, the impact on human life and property - not the impact on the environment - is the number one concern in the minds of fire officials when deciding whether to conduct a controlled burn. Second, and perhaps more importantly, evidence shows increasing the frequency or area of controlled burns does not necessarily reduce the bushfire risk.

In fact, during extreme fire danger conditions, reduced fuel loads - such as those achieved through hazard reduction burning - do little to moderate bushfire behaviour.

controlled burns often fail to slow a bushfire Firefighters protecting homes near Woodford, NSW as a bushfire approaches. AAP

Officals under heat to cut fuel loads

Hazard reduction burning, also known as prescribed or controlled burning, is primarily used to prevent the spread of bushfires by reducing the build-up of flammable fuel loads such as leaf litter, grasses and shrubs.

Authorities routinely come under pressure to reduce bushfire fuel loads - especially in the wake of a bushfire crisis like the one seen on the east coast in recent days.

Media and mining magnate Kerry Stokes this week called for more controlled burning, saying this was a more pressing concern than climate change in dealing with bushfires.

And Nationals MP Barnaby Joyce reportedly lashed out at the Greens and others for purportedly opposing controlled burning and land clearing, claiming “there is all this bureaucracy that stands in the way of people keeping their place safe”.

The hazards of hazard reduction

controlled burns often fail to slow a bushfire Nationals MP Barnaby Joyce this week said ‘bureaucracy’ was getting in the way of rural landowners conducting hazard reduction on their properties. Lukas Coch/AAP

Bushfire hazard reduction is not as simple as dropping a match indiscriminately and standing back to watch the landscape burn. Fire agencies must assess the risks and manage the potential impacts. These assessments are made in the years and months prior to the burn, as well as on the day.

Fire authorities invest significant time preparing for a controlled burn program. They work with communities to develop a plan and a rigorous process guides how, where and when the burns will be undertaken.

Protecting human life and property from the effects of a burn is the first priority, and by far represents the greatest challenge. Other impacts are also assessed in the process. These include effects on the environment, Indigenous and European cultural assets and sporting events.

Read more: Mr Morrison, I lost my home to bushfire. Your thoughts and prayers are not enough

Despite extensive planning, over the past decade prescribed burns have escaped containment lines and destroyed houses, such as at Margaret River in Western Australia in 2013 and Lancefield, Victoria in 2015. To prevent a repeat of this, policies require burns only proceed when the weather is suitable not just on the day, but for three to five days afterwards. This has meant many burns do not go ahead or are delayed for years.

Smoke from fires can increase mortality and hospitalisation rates, and so the effect on human health is playing an increasing role in whether to burn or not. Viticulture concerns have also delayed burns because smoke can also destroy grapes used in wine production.

controlled burns often fail to slow a bushfire Thick smoke blankets Sydney Harbour in May 2019 after hazard reduction burns. AAP

Controlled burns may not slow bushfires

Even if we were to carry out more controlled burns, it does not necessarily follow that bushfire risk would be reduced.

Controlled burns do not remove all fuels from an area. And forests accumulate fuel at different rates - some return to their pre-burn fuel loads in as few as three years.

Read more: 12 simple ways you can reduce bushfire risk to older homes

Our research has shown controlled burning was likely to have reduced the area later burnt by bushfires in only four of 30 regions examined in New South Wales, Victoria, South Australia and the ACT.

Evidence from a range of studies demonstrates fuel loads can significantly modify fire behaviour under benign weather conditions. But reduced fuel loads do little for bushfire mitigation under extreme fire weather and in times of drought.

controlled burns often fail to slow a bushfire A burnt-out structure on a property devastated by bushfires at Coutts Crossing in Northern NSW, November 2019. Jason O'Brien/AAP

Looking to the future

Evidence is mounting of increased bushfire frequency and extent in both Australia and the US - a situation predicted to worsen under climate change. Changing weather patterns mean opportunities for controlled burning will likely diminish further. Coupled with expanding populations in high fire-risk areas, Australia’s fire agencies - among the best in the world - have a challenging time ahead.

Read more: How we plan for animals in emergencies

In future, we must think beyond traditional approaches to fire management. Acknowledging the role of climate change in altering natural hazards and the impact they have on humans and the environment is the first step. Communities should also be at the centre of decisions, so they understand and act on the risks.

Authors: Trent Penman, Associate professor, University of Melbourne

Read more http://theconversation.com/a-surprising-answer-to-a-hot-question-controlled-burns-often-fail-to-slow-a-bushfire-127022

NEWS

Morrison won't have a bar of public service intrusions on government's power

Scott Morrison has rejected or sidelined a number of recommendations from the long-awaited Thodey review.AAP/Paul BravenScott Morrison has rejected or sidelined a number of recommendations from the long-awaited Thodey review...

Michelle Grattan reflects on the year in politics

For their last video for the year, University of Canberra Vice-Chancellor Deep Saini and Michelle Grattan look backwards to the big issues which have shaped political discourse. They discuss the...

no wonder many Christian men today are having a masculinity crisis

How men saw God shaped how they saw themselves, and in turn, how they saw women. WikimediaThis article is part of our Gender and Christianity series.To understand contemporary Christian ideas...

Australia needs a national crisis plan, and not just for bushfires

Bushfires aren't the only catastrophic emergency Australia is likely to see. AAP Image/Mick TsikasCalls are growing for a national bushfire plan, including from former prime minister Malcolm Turnbull, who says...

Your Christmas shopping could harm or help the planet. Which will it be?

Many Australian consumers are concerned at the environmental impact of their shopping habits, especially at Christmas.AAPAustralian shoppers are set to spend $52.7 billion this Christmas. In the words of the...

Right-swipes and red flags – how young people negotiate sex and safety on dating apps

For many young people, app dating is just part of regular dating life.freestocks.org/UnsplashPopular commentary on dating apps often associates their use with “risky” sex, harassment and poor mental health. But...

Bougainville has voted to become a new country, but the journey to independence is not yet over

The Autonomous Region of Bougainville, a chain of islands that lie 959 kilometres northwest of Papua New Guinea’s capital, Port Moresby, has voted unequivocally for independence.The referendum saw 85% voter...

Friday essay: eco-disaster films in the 21st century

A scene from the 2017 film Geostorm: many societies have historically attempted to deal with collective trauma by replaying and restaging it in art.Warner Bros., Electric Entertainment, Rat Pac-Dune EntertainmentIt...

A new study shows an animal's lifespan is written in the DNA. For humans, it's 38 years

A genetic "clock" lets scientists estimate how long extinct creatures lived. Wooly mammoths could expect around 60 years.Australian MuseumHumans have a “natural” lifespan of around 38 years, according to a...

Australia's wafer-thin surplus rests on a mine disaster in Brazil

On Monday the Australian government will release the Mid-Year Economic and Fiscal Outlook (MYEFO). This will – as required by the Charter of Budget Honesty – provide an update on...

these 5 charts show our democracy is safe in the hands of future voters

Almost 900 school kids, aged 12 to 17, were surveyed.ShutterstockA new, ongoing survey on how young Australians understand and imagine their democracy is already challenging long-held stereotypes. The survey –...

Private health insurance premiums should be based on age and health status

Policy changes have failed to stop young people dropping their private health insurance.ShutterstockPrivate health insurance has come under intense scrutiny in recent months, as it becomes clear health insurers are...

Popular articles from Modern Australian

Are Root Canals for Baby Teeth Necessary?Simple Yoga Exercises to Stretch and Strengthen7 Tips for Effective Spring Cleaning Stress Less - 5 Tips For Getting Through The Holiday Season On A Shoestring BudgetMesmerising Interior Design Trends for 2020 That Will Transform Your HomeTips for Sports BettingWhat Essentials to Consider to Avail Right Insurance Policy6 Essential Features You Should Consider Before Buying a Ski WatchNew or Used Car: How to Select The Best For Your FamilyChoosing a home builder in SydneyWhy regular visits to the eye doctor are important6 Budget Tips for a Student Studying Abroad in Australia5 Ways to Style Your Winter Wardrobe Essentials Into Versatile Outfits5 Brisbane Summer Classes Your Teens Can AttendSummer Gardening Tips