Bushfire knowledge is not all about the study of literature and seeking advice from experts. It’s important to be aware of the popular misconceptions about bushfires which can be misleading or dangerous.
At a recent webinar, Owen Gooding provides an insight into commonly held misconceptions and myths surround bushfire.
Available Resources
There are very few resources published that address common bushfire myths and their limitations. The following were identified January 2024.
- FNPW website Environmental Challenge Firewise page – https://fnpw.org.au/project/fire-wise/
- CSIRO Bushfire Myths page- https://www.csiro.au/en/news/All/Articles/2019/December/extinguishing-bushfire-myths
- Victorian Curriculum and Assessment Authority, Bushfire myth buster PDF-https://www.vcaa.vic.edu.au/Documents/viccurric/bushfire/learning/BushfireMythbusters.pdf
- Queensland Government, Bushfire aware page- https://www.qld.gov.au/emergency/dealing-disasters/disaster-types/bushfires/bushfire-aware/bushfire-myths
- Shire of Denmark (WA), Be bushfire ready page- https://www.yourdenmark.wa.gov.au/be-bush-fire-ready/news_feed/common-bushfire-myths
- News.com, The myths around Australia’s horror bushfire season debunked- https://www.news.com.au/technology/environment/climate-change/the-myths-around-australias-horror-bushfire-season-debunked/news-story/199c41bf9eb5af07a75575fea278c1f8
The following information is offered as a suggested narrative to organise key messages and supporting resources that address common bushfire myths relevant to rural landowners.
The scope of this myth narrative will be of particular interest to landowners interested in land custodianship and biodiversity conservation such as Landcare group members, or those who want to minimise environmental harm when pursuing bushfire safety.
It is not an exhaustive list. It will continue to grow and refine with discussion and necessarily to accommodate emerging research and changes in language.
“Bad bushfires are caused by high fuel loads”
Fire intensity is characterised in bushfire behaviour texts as a function of fuel, weather and topography. Yet fuel load is often spoken about as if it is the most important measure of bushfire risk.
You will often figures quoted for tons of fuel per hectare. However, fuel arrangement is far more important contributor to fire behavior than fuel load. This is why garden and landscape advice for bushfire risk management talks about establishing separation between flammable objects, and fire services and public land managers in Australia quantify overall hazard in terms of fuel structure.
You may sometimes hear talk about fuel ladders. This concept refers to the vertical connectivity of fuel elements in a forest from leave litter into small plants, then through taller shrubs, climbers and tree bark to the tree canopy (together known as the elevated fuels) all the way to the tree canopy.
Separation between these layers will prevent a surface bushfire turning into a crown fire. A crown fire is the most energetic of all forest fires. To maintain spread as a crown fire it must be supported by strong wind, continuous elevated fuels or steep upslope in the direction of wind travel. A crown fire will drop where there is insufficient elevated fuels underneath the tree canopy and there are breaks in the canopy continuity.
Resources
The larger more energetic fires that cause the greatest losses are driven by weather, the large area of fire and topography. The destructive power of highest intensity fires such as Ash Wednesday and Black Saturday, weather is the dominant driver, and the behavior has very little to do with the fuel it is burning through. These fires are coupled with the upper atmosphere casing embers to be hurled tens of kilometers ahead of the fire, lightning, and cyclonic wind speed at ground level.
Resources
Bushfire survival is much more than a matter of the vegetation management around our assets and fuel reduction at a landscape scale. Its function of many elements all acting together.
All Australian fire authorities recommend that the safest option for people is always to not be in high risk aeras when there is bushfire, and to leave early, especially on Extreme and Catastrophic risk days. All sources recommend individuals have family or business have a survival plan
Reducing the likelihood of house loss is not just about a well-designed and maintained Firewise garden. Houses have structural weaknesses that allow embers to enter a building.
Structural vulnerability can be minimised by retrofitting buildings, particularly ember entry points in walls, under floors and in roof spaces. Replacing flammable elements such decking and facia boards with non-flammable alternatives is worth considering as is screens for windows and doors.
Resources
CSIRO- A guide to retrofit your home for better projection from a bushfire
“You have to clear the bush to be safe”
Flammability has nothing do with where a plant originates from. The flammability of the plant comes down to its physical properties, its stage of life, health and site conditions including soil type, climate and weather. The contribution of a plant to bushfire risk depends also on where it sits in the landscape in relation to the assets we wish to protect and flammable elements such as other plants and hard landscaping.
Resource
A positive role of vegetation in a bushfire
Plants can have a beneficial role in bushfire event by slowing down surface winds, shielding assets from radiant heat, reducing umber load on an asset, and through shading which reduces evaporation.
Resources
Bushfire safety is far more that managing the stuff that burns. Families and rural businesses will need to have personal survival plans and adequate insurance.
Resources
RFS Bushfire survival plan https://www.rfs.nsw.gov.au/resources/bush-fire-survival-plan
“You have to cut down the trees to be safe in a bushfire”
You’ll often hear people worry about trees or heavily treed areas as a bushfire risk. Or perhaps you hear that people are worried that they cannot get a permit to clear trees around a house.
Trees actually slow down the high-speed winds that are associated with destructive bushfires. A shady garden will also create a microclimate that retains more moisture than an exposed site. In other words, a house that has trees and other vegetation cleared around it will have greater exposure to bushfire attack.
Native vegetation including large old trees provide important habit for native species.
Resources
CSIRO- https://www.csiro.au/en/news/All/Articles/2019/December/extinguishing-bushfire-myths
The Fire Wise project of Foundation for National Parks Wildlife (FNPW) promotes use of strategic planting of native species to enhance biodiversity and reduce bushfire risk- https://fnpw.org.au/project/fire-wise/
When landscaping for bushfire trees need to selected based on flammability, a maintenance program and where possible locating them so that a tree is distant enough that it will not strike a building or other asset when it fails as consequence of a bushfire event.
CFS (SA)- Risk Management of mature/large trees on residential properties- https://resources-production.safecom.sa.gov.au/current/docs/Mature%20tree%20position%20statement.pdf
CFA, Landscaping for Bushfire
10/30 10/50 Rule, Victorian Government. Vegetation be removed or modified for bushfire protection without requiring a permit. In Victoria it is known as the 10/30 and 10/50 rule– https://www.planning.vic.gov.au/guides-and-resources/guides/all-guides/bushfire-controls/vegetation-removal
‘If we plant exotic trees around houses then more houses will survive bushfire”
The idea that less flammable non-native trees will protect houses in bushfires is probably related to the misconception that the bush and native species are the problem in bushfires. There are many examples of houses surrounded by Oaks and other deciduous species being lost in bushfire. The most common loss mechanism in these cases will be embers getting into the building. Ember protection is achieved by retrofitting existing dwellings with a complimentary ‘Firewise’ garden.
A Firewise garden can have tree species that originate from anywhere of the world just as long as its flammability has been taken into account with selecting, locating and in maintenance.
Resources
CFA- Landscaping for Bushfire, CFA
Firewise Gardening in Western Australia, Department of Fire and Emergency Services
“Roadsides are bushfire wicks”
The role of vegetation road reserves and roadside management in bushfire spread or risk is very commonly raised after a significant bushfire and in bushfire inquiries. Some people have referred to vegetated roadsides as ‘wicks’ which implies the vegetation carries a bushfire into an area where our assets are located, therefore increasing risk.
This myth can be expanded to include concerns about riparian areas and revegetation projects. They are all linear elements in a landscape.
Bushfire travels faster in grassland than in forested areas. Consequently, a fast-moving grass fire will slow when it hits a forested environment. Riparian areas commonly have more shade and are moister than surrounding areas, and this moisture can reduce the fire behaviour.
In a rural landscape forested road reserve vegetation is narrow given the width of a reserve and the pavement. For a fire in a roadside forest to reach high energy levels the prevailing winds would have to follow the road alignment exactly and for long distances. This circumstance is extremely unlikely to occur.
The 2009 Victorian Bushfires Royal Commission sought advice from fire behaviour experts in ration to the contribution of roadside vegetation to losses associated with the Black Saturday fires.
The Royal Commission concluded that road reserve vegetation had no effect of the overall spread of the fires. It also recognised that road reserves often carry habitat and high biodiversity values, and therefore the people of Victoria need support to reconcile conflicting road reserve management objectives and satisfy all relevant legislative requirements.
Resources
2009 Bushfire Royal Commission – Final Report Summary– http://royalcommission.vic.gov.au/finaldocuments/summary/PF/VBRC_Summary_PF.pdf
2009 Bushfires Royal Commission Volume – 1 Fire Preparation, Response and Recovery Chapter 7 Land and Fuel Management– http://royalcommission.vic.gov.au/finaldocuments/volume-2/PF/VBRC_Vol2_Chapter07_PF.pdf
Roadside Fire Management Guidelines, CFA
The Riparian Land and Bushfire – resource document explores the effects of riparian vegetation on fire behaviour. The information applies equally well to considerations around other vegetated landscape features such as roads reserves, and revegetation projects either on public linear reserves or private land.
Riparian Land and Bushfire website – https://www.water.vic.gov.au/waterways/riparian-land/floods-and-fires-on-riparian-land
Riparian Land and Bushfire resource document– https://www.water.vic.gov.au/__data/assets/pdf_file/0034/669355/riparian-land-and-bushfire-resource-document.pdf
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