What is the science behind increased hazard reduction burns?

[FatCanyoner]

G'day folks,

The NSW Government yesterday announced that they would be doubling the amount of hazard reduction burns happening in National Parks, as part of yesterday's budget.

“By doubling the amount of hazard reduction in our national parks and boosting fire fighting resources over summer, we’re funding the biggest ever fire management program" -- NSW Environment Minister Robyn Parker
-- http://www.budget.nsw.gov.au/__data/*&%$#! ... ritage.pdf

Given that huge areas have been getting burnt over the last few years following Black Saturday, this seems like a truly massive amount of burns (there have been lots of last minute bushwalk cancellations this year alone due to hazard reduction burns).

I'm curious what the science is behind this. Is the doubling an arbitrary thing, or is there some evidence more burns are needed? Does anyone know what, if any, monitoring or research is being done around the environmental effects of hazard reduction burns? Are there environmental risks? When are the best times / types of fires environmentally? Does that coincide with the best time to do safe hazard reduction burns?

I have heard a lot of mixed messages on this topic. On the one hand, there's the argument that any reduction in fuel loads is a good thing. On the other side I've heard that the burns do little to slow bushfires, and can actually be damaging. An ecologist I know told me recently they refer to many of these fires as "hazard increasing burns", because they actually cause a build up of fuel. Apparently, if you go to some areas six months after a low intensity hazard reduction burn goes through you will find more fuel on the ground because all the leaves and many branches fall following the fire, and there is lots of lush new plant growth too. The same person told me that many of these cold, winter burns are too cool to germinate some native plants that require fire, effectively harming their reproduction. On the other side of the ledger, many weeks respond well to these fires, so in some wilderness areas they are promoting weed expansion.

Does anyone have expertise on this? Or some good research? Or even anecdotal evidence one way or the other?

[Rob A]

Yes, entire tracts of our local coastline have been left in the hands of bitou bush as a result of repeated burns that were ... "needed".
Clowns in Parks are amongst the worst of them. We also had coastal rainforests that are now gone.
It all stems from the fallacy that fires are a natural part of the australian landscape.

[stepbystep]

Have you read Bill Gamage's 'The Biggest Estate on Earth'?

Lot's of food for thought in there in relation to modern management of a landscape that was managed far more intensively over ten's of thousands of years.

[FatCanyoner]

Have you read Bill Gamage's 'The Biggest Estate on Earth'?

Just read a review from The Monthly. Sounds very interesting. I'll have to pick it up.

[Moondog55]

A hazard reduction burn is supposed to remove stuff less than a centimeter in diameter, kindling in other words. It is really labour intensive, expensive and difficult to do properly.
We want to be "safe" but are not prepared to pay for that state so what do you expect?

[Pteropus]

It will be interesting to see what areas they will target, and when they target them, with so called hazard reduction burns, and what their expected outcomes are. For example, if the outcomes were to protect private property, then it is better to conduct targeted burns to reduce fuel loads close to private land, rather than conducting large-scale hazard reduction burns across bushland (see http://www.provender.com.au/fohc/FireReport-Gibbons.pdf). This article printed in the conversation just yesterday discusses the monetary cost of poor bushfire management.

However, as FatCanyoner's friend points out, fire can cause ecological problems, such as changing vegetation structure, including the proliferation of woody and grassy weeds which can respond positively to fire, and which can increase the frequency of hot fires. If fires are conducted for ecological reasons, they need to be conducted at the right time and take into account when plants are flowering and producing seed. Note that many species including Acacias and Banksias are flowering in late autumn, winter and early spring, and are producing seed for the hotter months. However, many burns are conducted in the cooler months when these plants are flowering, to minimise the risk of fires getting out of control or reigniting, as may occur in the hotter late spring and summer months. Incidentally, it is likely that many of the plants that are fire adapted are expecting fires in late spring and summer, at least in the southern parts of Australia. This issue of species and timing introduces a problem for any environmental management activities, where there are few, if any, rules of thumb for applying one management action across whole regions. Appropriate fire regimes will depend on the location and ecosystems involved, and hopefully be based on research. Which brings me back to my opening sentence: It will be interesting to see what areas they will target, and when they target them, with so called hazard reduction burns, and what their expected outcomes are.

[Hallu]

I would increase air surveillance and fire education instead. A lot of fires and triggered by human activity (accidental and criminal), why not spend your money on that... Or spend money on relocating people living too close to dangerous zones, improving evacuation drills etc... As you said, we don't even know for sure these hazard reduction burns work, the science behind it is too sketchy, so just stop doing it...

[maddog]

There is not much evidence to suggest that current State governments are managing the parks to enhance conservation outcomes, so it will be interesting to what degree NPWS retain control.

A conservative approach, rather than enthusiastic zeal, may avoid unintended consequences. As an example, efforts to control brigalow in southern Queensland. According to Gammage, this vegetation community spread rapidly after european settlement displaced the aboriginal land management. When the europeans attempted to use fire to control the brigalow, as they had witnessed the aboriginals do, it grew back thicker than ever. 'Yet people burnt it clear in 1788. They knew which fire regime worked. We don't'

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[roysta]

I'm not sure about the science but one thing is certain.
The fuel loads on the ground in many parks close to Sydney, including right on top of heavily populated zones, are enormous.
It takes just one or two arsonists to fire it up and away we go.
We haven't had burns (hazard reduction or otherwise) in some places for years.
Better to be safe than sorry, although, the earlier reference to certain 'clowns' did ring a bell.

[nq111]

One idea is frequent burns are far cooler (less fuel) and do minimal damage to wildlife and fauna). Certainly a little grass fire just freshens up most Australian bush. Occassional burns have lots of fuel and tend to be too hot - even kill native species adapted for fire. Also, infrequent burns may happen at the worst time (40 degree southerly bluster?) and cause far more damage then necessary.

Though there must have been the odd catastrophic burn predating europeans - otherwise we wouldn't have the massive ash forests down south.

[climberman]

Robyn Parker - more burns, shooting, orica, logging helps koalas, staff slashing; what a legacy.

[clarence]

It is a good question. UNfortunately there is substantial misinformation about the issue, which has already come out in some of the responses to date. I could answer many of the questions, but would be here all night.

To state that the "science behind it is sketchy" is completely incorrect. To follow on with.."so just stop doing it" is a bit too simplistic.

I worked in this field for several years and have postgraduate qualifications in fire ecology. For those of you who are genuinely interested in getting an understanding of the topic, may I suggest the book "The Ecology of Fire" by Rob Whelan. Very readable, comprehensive and science based.

A few points:

Fire ecology has been studied scientifically for about 50 years, and not just in Australia. There have been hundreds of scientific papers in peer reviewed journals that have been published over the years. These have looked at everything from the responses of individual species, to fuel load accumulation, to broad scale and long term fire management.

It is correct that too frequent burning can lead to more fire-prone vegetation communities in certain situations, and hence exacerbate the fire risk- however, it is a far more complex scenario than just frequency of burning.

The timing of flowering and seed set in a given season is generallyonly partially relevant. What is more relevant is the time (for species which regenerate from seed only) taken to reach flowering and seed set. If fire intervals are shorter than the time taken to germinate, grow, flower and set seed (usually a minimum of 6-8 years for seed regenerating banksias, hakea etc) they will eventually dissappear. To make it more complex several species are specifically adapted to sub soil dispersal of seed (by animals) and these can lay dormant in the soil for many years until a fire triggers germination (in particular the acacia and related species). Other species will regenerate multiple times from woody root systems, and can generally tolerate fairly frequent burning. Other species (like the waratah) resprout from a woody root and flower and release seed a few years after a fire and will have their most prolific flowering and seed set in the few seasons immedately after a fire. It probably sounds very complex because it is. (If you are still interested refer to the book above).


It is a highly political and emotionally charged issue (especially now that the Black Saturday bushfires eclipsed the 1902 Mount Kembla mine disaster as the largest peacetime loss of life on Australian soil). Emotion aside, the mechanisms behind it are reasonably well (not completely) understood. As with many ecological systems there is a fair range of natural variability which could reasonably be expected. Politically also, there is some variability in how the priorities are managed (ie conservation vs appeasing public fear). Although I am no fan of the NPWS generally, the staff there overall have a very good understanding of the mechanisms of fire and its impact on the environment. How political pressures are dealt with through the management heirarchy is another story. It is entirely possible that these "acceptable limits" regarding fire management are pushed to the extremes in certain political climates.

Clarence

Last edited by clarence on Fri 21 Jun, 2013 5:02 am, edited 1 time in total.

[Lotsafreshair]

One question Clarence... Can the problem be solved with a Krav "thumb" move to simply bring it down?

[Lotsafreshair]

On a serious note though, I was recently in the lower Gangerangs and Wild Dogs and was so impressed by the job that the teams had done on the hazard reduction burn. For such a vast area, they had managed to keep it to the under storey, clearing all the fuel load, whilst the trees and canopy remained in tact. Or in another case, where the burn went up to the foot pad or track on one side and didn't go on the other. It got into the canopy in only a few spots (notably Mt Mouin), but when you consider the task at hand, this minimal scarring was quite a testament to the skill of those doing the burn. I say well done guys... And I'm currently reading "The biggest estate on earth."

[Pteropus]

The timing of flowering and seed set in a given season is generallyonly partially relevant. What is more relevant is the time (for species which regenerate from seed only) taken to reach flowering and seed set.

Yes, as you say the frequency is very important for many plant species. The relevancy of timing of fire when plants are flowering is also important because it provides a food source for many species such as numerous bird species, mammals and of course, insects. Animals may survive the fire, but a paucity of food can follow, with potential negative effects on animal populations. Of course this can happen with any fire, but burn planning should consider secondary impacts of a fire on both flora and fauna.

[hunsta]

I have one question. Any volunteer rural fire fighters making comment in here?

[Moondog55]

Me, but at my age I am no longer active and out of date

[hunsta]

I was just interested to hear what they may have to say on the subject. As they are the ones who have to put their lives on the line when "controlled burnoffs "get away.

[Moondog55]

In my brigade [ Falls Creek] we were whinging for years that not enough winter burning was happening.
Personally I think the problem of kindling fuel on the ground has increased markedly since campers and bushwalkers stopped cooking on open fires, but that is only my personal opinion

[jackhinde]

agree with clarence as to the book recommendation (slight bias as rob was a lecturer of mine), also recommend stephen pyne's Burning bush, dated and full of flowery language but interesting as it was written by an american outsider. Gammage's book is well researched in regard to ethnographic evidence but a little light on ecology.

[Gippsmick]

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[clarence]

by Lotsafreshair » Thu 20 Jun, 2013 9:03 am

One question Clarence... Can the problem be solved with a Krav "thumb" move to simply bring it down?

Please explain? A "Krav thumb" sounds like a big wall climbing move to me.

clarence wrote:The timing of flowering and seed set in a given season is generallyonly partially relevant. What is more relevant is the time (for species which regenerate from seed only) taken to reach flowering and seed set.

Yes, as you say the frequency is very important for many plant species. The relevancy of timing of fire when plants are flowering is also important because it provides a food source for many species such as numerous bird species, mammals and of course, insects. Animals may survive the fire, but a paucity of food can follow, with potential negative effects on animal populations. Of course this can happen with any fire, but burn planning should consider secondary impacts of a fire on both flora and fauna.

I agree Pteropus. (I was referring firstly to vegetation, which is more my area of expertise). As I said, it is a very complex issue, and differs hugely for different animal species depending on mobility, feeding patterns, their reproductive cycle, where they live etc. (For example a bird can easily fly away, then fly back a few days or weeks later if it wants. A wallaby on the ground which can neither move faster than a fire front nor hide is a hole, is probably screwed.) At one extreme a patchy and cool fire will have minimal impact on many animal species, however the animals can potentially recolonise very quickly and this may hinder the regeneration of certain plant species. At the other extreme a large hot broad-scale fire will totally wipe out certain species which will be forced to recolonoise from further afield. After a large complete burn, for example, a bird could fly a few km away and forage on flowers in unburnt bush. A cool patchy burn, as an alternative example, may indeed favour a wallaby which able to take advantage of the flush germination/resprouting after the fire. This is where the mix of season, intensity, patchiness, fire interval, presence of "refugia" (ie areas which are "safe" from fire, like wet rainforested gullies) etc all come in to play. As Gippsmick said, burning based solely on reaching hectares per annum targets is not fantastic unless it take into account a whole raft of issues (including whether the area is a genuine fire risk at all in the first place).

On that issue, I would argue that barriers to recolonisation for mammal species is a more significant issue than the area or season of the burn. Take, for example, the large scale fires in Royal NP in the last 30 years where nearly the whole park has been burnt. For mammals to recolonise from adjacent bushland (catchment areas, Heathcote NP) is a dicey affair with a railway and major freeway, suburbia etc blocking access. Hence, any residual populations (if there are any at all) on the east side of the freeway are far more likley to recolonise- making it possibly slower, but also meaning the whole park may be filled from a very limited genetic stock in the longer term- which is another story. Throw in a few cats and dogs in the unburnt bush on the urban fringe, where small mammals may preferentially feed, and it complicates regeneration further. In the case of the Wild Dog burns, this opposite is probably true as there is a huge perimeter from which mammal recolonisation can occur without impediment. It is all part of the mix that must go in to fire planning.

I recall a huge fire in the Blue Breaks in about 1995, and another on the tablelands around Belloon Pass in the late 1990s. Both of these were probably a few thousand hectares- not too different to the recent Wild Dog burn. When an unplanned burn occurs, in come the the helicopters with fire retardant, bulldozers, fire tankers, back burn lines etc etc. The newly made bare earth "control lines" create entry points for feral animals, weeds, greater erosion, trailbikes etc etc. One could argue that a controlled and planned burn like the Wild Dogs is no more destructive than these unplanned burns and the human impact of trying to manage them in a similar landscape

What is also worth noting, and which has not been stated, is that an interval between fire which is "too long" can also have negative consequences from a conservation perspective, as certain species will also decline (in either absolute or relative measures) over time. This goes for both plants and animals.

It is also worth noting that over time fuel loads do NOT continue to increase at the same rate, and eventaully more or less plateau out. The natural breakdown by rotting, termites, microorganisms etc allows a more or less steady state to be acheived in the longer term.


AS I stated, it is a very complex and fascinating topic and if you are generally interested I would refer you to the book by Whelan. (It is a good mix of readability and science by a world leader in the field.) Reading such material can give a typcial outdoors person a much better understanding of the way our landscape works. Having an understanding of our natural environment and how it works is a good thing and can make one appreciate and view the bush in a different way.

Clarence

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[clarence]

The above entry was duplicated here and is now deleted- I still don't have the editing feature sorted fully.
Oops
Clarence

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[Pteropus]

Another good book that lays these complex issues out, often in point form is Australia Burning: Fire Ecology, Policy and Management Issues. Eds Geoffrey Cary, David Lindenmayer and Stephen Dovers.

[FatCanyoner]

Sorry for the slow response. I was away on the weekend and have been hectic with work. Some amazing thoughts already, and links. I need to make some time to digest it all and I'll come back with some more questions.

[David M]

I question why we need artificial fires in the Australian bush anyway. It's certainly true that the life cycle of many Australian plant species depends on natural fires from lightning strikes but to keep regularly burning the bush like Aborigines did just because they were "fire farmers" surely does not lead to a "natural" state of the bush either.

And people should not live in fire-prone areas without appropriate clearing around buildings, sprinklers and fire-resistant buildings.

[maddog]

I question why we need artificial fires in the Australian bush anyway. It's certainly true that the life cycle of many Australian plant species depends on natural fires from lightning strikes but to keep regularly burning the bush like Aborigines did just because they were "fire farmers" surely does not lead to a "natural" state of the bush either.

And people should not live in fire-prone areas without appropriate clearing around buildings, sprinklers and fire-resistant buildings.

The argument is that aborigines have been pattern burning the landscape for so long, that many surviving plant and animal communities have come to depend on it. The 'natural state' is no longer desirable. If this is correct, by abandoning aboriginal fire management techniques we have reduced diversity at the landscape level, and many species now find survival difficult. The risk of wildfire also increases.

Thanks to Gammage, the subject should keep ecologists and land managers busy for the next decade or so.

Cheers

[clarence]

I question why we need artificial fires in the Australian bush anyway. It's certainly true that the life cycle of many Australian plant species depends on natural fires from lightning strikes but to keep regularly burning the bush like Aborigines did just because they were "fire farmers" surely does not lead to a "natural" state of the bush either.

And people should not live in fire-prone areas without appropriate clearing around buildings, sprinklers and fire-resistant buildings.

Good point David. It is only because the aboriginals have probably been doing it for thousands of years that makes a difference. Carbon/charcoal core records show substantially more fire activity in the Australian landscape for tens of thousands of years, so even though it is human induced, it has been happening for so long that it is not "artificial" as such.

Since the Victorian fires the Building Code of Australia and Australian Standard for construction in fire prone areas have been completely overhauled. The requirements of these standards will mean the cost and complexity of building houses in bushfire prone areas will be hugely increased. I think it will be a huge deterrent to further house building in fire prone areas, and already certain projects are no longer getting across the line (for cost and technical reasons) because of these upgraded regulations.

Clarence

[climberman]

Good point David. It is only because the aboriginals have probably been doing it for thousands of years that makes a difference. Carbon/charcoal core records show substantially more fire activity in the Australian landscape for tens of thousands of years, so even though it is human induced, it has been happening for so long that it is not "artificial" as such.

Clarence

Note though that the evidence shown by the charcoal record is NOT uniform across the country, with many environments showing much less fire evidence in pre-history than the historic period. The Snowy Mts are a good example of this.

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[roysta]

Please explain? A "Krav thumb" sounds like a big wall climbing move to me.

Google krav maga and all will be revealed.
But it sure as all hell ain't a big wall climbing move.... something much more serious.