You are here

ABC podcast: Controlled burns destroy ecosystems and may not reduce fire risk

Some of you may have noticed how 'debate' about the terrible bushfires has, as usual, turned into a 'backburning and fuel reduction' vs 'greenies'. The mass media is in general promoting a firebug economy. Other voices are not heard, even in Victoria, this most cleared state. We have already published Joel Wright, aboriginal historian's argument that there is no record of big controlled burns by aboriginals in Australia, Jill Redwood, "Firebug economy," and Bob MacDonald on the contribution of wildlife to fireproofing the forests. This ABC recording from Professor Kingsley Dixon is a real voice of sanity in an otherwise truly incendiary debate.

Transcript below:

Controlled burns destroy ecosystems and may not reduce fire risk

As fires rage across five Australian states, well ahead of the expected bushfire season, debate rages about our fire management of forests. Some call for more controlled burning during cooler months, thinking this will decrease the rate of uncontrolled fires. But biologist Kingsley Dixon explains, so-called prescribed burning, produces a more flammable system in the first years after a fire. And he says there are devastating effects on the natural ecology. He says whereas some forests may experience a natural fire every 80 years, there is no chance for the ecosystem to re-establish when that frequency becomes a prescribed burn every five years.

Robyn Williams: The Science Show on RN, and the research about fire tells us an interesting and surprising story. This is Professor Kingsley Dixon from Curtin University in Perth.

Kingsley Dixon: It's interesting, fire restarts the ecology in Australian systems. The fires that occur through lightning ignitions are completely natural fires because they would have always happened through lightning ignitions. The issue that we now face on the continent is not so much the intensity of the fires that we are facing, but the frequency of the fires because we have now overlaid imposed fire. This is things such as prescribed burning. And really fabulous new information coming out of a couple of the major research groups in eastern Australia is showing that prescribed burning in fact, as we have now found with the eastern states fires, tragically don't stop the fires we are facing. This is actually a climate change issue, and that by prescribed burning at those lower temperatures, what you do is you drive a more flammable system within those first five years, so then it takes fire again and again, and then the loop is welded into the ecology. When you do those high-frequency fires, that's when you lose your diversity, that's when you lose many of the species we are talking about.

So it's all around the frequency. Natural fire frequencies in some of our systems like the jarrah forest are 80 years or more. We now put them on six-year rotational burns. So you can see the consequences of that are quite catastrophic. Importantly, for things like many of our fauna, they need long unburnt patches as their refugia. It can be everything from millipedes to native marsupials need the rich organic matters that come from long periods unburnt.

And some interesting data I was shown last week which is soon to be published with the fires in New South Wales is that many of those fires actually stopped on the margin of forests that were long-term unburnt. They had built up a resistance to that. And so that's stuff that is now being talked about in New South Wales. So coming back to the original question, fire is the restart of the system, what we do as European people, and not based on Indigenous fire regimes, this is in temperate Australia, certainly is not ecologically sound.

I have a colleague who has referred to the prescribed burning frequencies now that we are imposing, particularly in south-west Australia, as ecocide because of the frequencies and the devastation on treasured systems that we know escape fires for long periods and have some of our major Gondwanan relic species, and these can be from rare fish to important plants like the Albany pitcher plant.

Robyn Williams: So if it's not back-burning to save the forest from fire, the trees from fire, indeed cities from fire, what do we do?

Kingsley Dixon: So back-burning is what you do when a fire is approaching, I understand that, that's fine. What we need is a more strategic approach as we've put in a review paper last year where we synthesised all the information on the unexpected impacts of prescribed burning, and the paper was quite a daunting prospect because we actually saw more data coming through that showed the negativity of that.

So what we then did was we spoke to a lot of people about alternatives, and the alternatives are rather than burning broad landscapes is to look at strategic management and fuel controls proximal to the dwellings and the cities and the towns. The issue will always be, no matter what you do, the large canopy fires will occur, so you have to take your protective measures.

Now, I think I can speak not only as a scientist but also as a person who has been embedded. The very famous 2016 Waroona Yarloop fires, that arrived at my front gate on January 7. We evacuated, we had taken all the precautions. We think we would have saved the property but what really did was a wind change. So by the grace of whoever, we managed to secure our property, but we had taken all the necessary precautions. We sat in an area that had intensive prescribed burning, so it wasn't going to save us, as we had in New South Wales. So I think ecologically we need to re-evaluate what we are doing and to be more strategic about how we apply fire in the landscape and look at the assets themselves rather than blame the bush.

Robyn Williams: The renowned Professor Kingsley Dixon from Curtin University in Perth. More from him in a Science Show next month.

Comments

Interesting to read another opinion other than reducing 'fuel loads', as if fallen trees and undergrowth were merely fuel and not ecological events. It would be interesting to do some research on areas that have had prescribed burning, compared to other similar areas, and get data on just how effective they are. Apart from hotter climate and more frequency of fires, we have burgeoning population growth, urban sprawl, and tree-changers, more and more living close to trees, country and native parks. Not to mention arson!

In the 1950s and 1960s the Otways was a dense damp temperate rainforest.

Cool temperate rainforest in Victoria covers the Otways, Central Highlands, East Gippsland and South Gippsland. This rainforest type generally exists in high rainfall, higher altitude fertile environments.

In the 1970s large swathes of Otway temperate rainforest were cut down for pine plantations. The Otways has since dried out considerably which seems to have affected the rainfall of all surrounding areas, including Geelong and possibly Melbourne too.