Understanding the ins and outs of a prescribed burn might help put your mind at ease if there’s one near you.
Do you live in an area where prescribed burns are carried out, but you’re not really sure what’s going on? Or do you worry when you hear about them on the radio because it’s close to a relative’s place or your family farm and you want to make sure they’re safe?
Maybe having a better understanding of what gets taken into account in preparing and carrying out a prescribed burn – and how it might help you if there’s a bushfire – will put your mind a little more at ease.
We know that prescribed burns are a preventative measure. They’re all about minimising the risk and impact of bushfires by reducing fuel loads in at-risk areas.
But what gets taken into consideration? What is the goal? Is your house being protected? What about the local bandicoot population?
Prescribed burning in South Australia involves targeted and careful preparation from the planning of the burn all the way through to monitoring how the area recovers.
Working out the land management goal is the first piece in the puzzle. That is, why does a certain parcel of land need to be protected?
All public land is classified as a particular zone, and while it might not be as easy to understand as your regular ABCs, it might help you understand why our fire crews do what they do – and help you feel a little more comfortable in the process.
A is for asset protection
Your life, your safety, and protecting your assets are front of mind for fire crews. So if your property is positioned adjacent to a national park or other public land, a narrow section of that land – between 40 metres and 100m – might be classified as an A-zone (like the sections marked in red in the image above).
The vegetation on that A-zone land is burnt in a prescribed burn to minimise the risk to nearby assets – which could be people, buildings or environmental assets – in the event of a bushfire. It aims to provide a buffer from radiant heat damage, flame contact and burning embers.
Property adjacent to an A-zone is given the highest level of protection which is why this zone attracts the most intensive bushfire protection strategy. To protect the safety of nearby assets, when the vegetation in this zone grows back to a potentially risky level another prescribed burn is carried out, which in some areas could be as often as every six years.
B is for bushfire buffers
Buffer zones are sections butting up against an A-zone and can be anywhere between 40m and 1 kilometre wide (marked as yellow in the image above). They are burnt in a prescribed burn either to complement an A-zone or to reduce the fire intensity of a bushfire and rate of spread. Managing this buffer zone with a prescribed burn makes it easier for crews to supress bushfires because of the reduced fire intensity.
C is for conservation and land management
C-zones are essentially the remaining parcels of public land that aren’t classified as A or B zones (green in the image above).
A prescribed burn might be carried out in these zones for a number of reasons. It could be to reduce fuel, to complement A and B zones, to benefit the park or landscape, or to benefit species of flora or fauna. For instance, it could help achieve conservation objectives such as regenerating the habitat for certain types of birds or animals.
With anything, there are exceptions to the rule. In fire management speak, they’re referred to as exclusion zones. These are generally put in place to protect things like important plants, animals and cultural sites. Stay tuned for the next part of this series to learn more about these exceptions.In the meantime, read more about two of our fire management crew members:Tony PrattandRob Laver.
The expertise for this highly skilled work resides in the South Australian Department for Environment and Water (DEW). DEW is also a brigade of theCountry Fire Service.
Main image: zoning map of Cleland National Park and surrounds