Bushfire hazard Reduction - worth it?

Bushwalking topics that are not location specific.
Forum rules
The place for bushwalking topics that are not location specific.

Bushfire hazard Reduction - worth it?

Postby wildwanderer » Fri 13 Apr, 2018 5:43 pm

As I choke through a day where Sydney resembles Beijing.. thanks to the bushfire hazard reduction going on.

I started doing some research. So far what I have read indicates the benefits are small as far as reducing bushfire risk. and there is increasing research that shows the small benefit is outweighed by the negative health consequences for communities of breathing in all the smoke from a reduction burn.

Some studies.
“In most bioregions prescribed burning is likely to have very little effect on subsequent extent of unplanned fire, and even in regions where leverage occurs, large areas of treatment are required to substantially reduce the area burned by unplanned fire. https://onlinelibrary.wiley.com/doi/abs ... /jbi.12579

“While it is intended that fuel reduction burns will be successful in reducing fuel levels with the minimum of damage to the forest, this is not always the case. Post burn assessments of the effectiveness of prescribed burns in the Blue Mountains in the period 1990 97 found that 30 per cent of the burns had a negative result, 40 per cent were sub-optimal, and 30 per cent could be rated as effective burns.(31) The negative results occurred when there was more "creation of fuel" than reduction of fuel, with "creation" of fuel being the fire's curing of fuels rather than consumption of them” https://www.aph.gov.au/About_Parliament ... 8#Appendix


As to the community health effects…This is pretty damming.
Dr Johnston co-authored an article, published today in the MJA, which reported the health impact of smoke pollution following six particularly smoky days due to hazard reduction burning around Sydney in May 2016.To conduct their assessment, the authors used public air pollution data from the NSW Office of Environment and Heritage, population and mortality data from the Australian Bureau of Statistics, and hospitalisation data from the NSW Ministry of Health.
They estimated that 14 premature deaths, 29 cardiovascular hospitalisations and 58 respiratory hospitalisations were attributable to smoke from hazard reduction burning during the 6 days.
“Our study highlights the potential scale of the public health impact when smoke affects a population of nearly five million people for several days.”

https://www.doctorportal.com.au/mjainsi ... g-serious/


6 days of hazard reduction = 14 estimated premature deaths.. How many people die in bushfires each year?

Im sure the hazard reduction fires reduce bush fire risk in some cases but does it outweigh the costs? Why not spend the funds for hazard reduction on more heli and fixed wing tankers..
User avatar
wildwanderer
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 997
Joined: Tue 02 May, 2017 8:42 am
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Fri 13 Apr, 2018 6:27 pm

I suspect they spend 50, 100 times the amount of funds on heli tankers etc than they do on Fuel Reduction already. Often the fuel reduction is done to give you a fighting chance of stopping the fires WITH all those aids still in place, especially on urban fringes

https://theconversation.com/explainer-b ... tion-20605

https://www.aph.gov.au/About_Parliament ... 03/03Cib08
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Fri 13 Apr, 2018 6:33 pm

https://www.smh.com.au/environment/haza ... kalvt.html

Plenty to keep everyone reading and chatting in that load of links
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Re: Bushfire hazard Reduction - worth it?

Postby taipan821 » Fri 13 Apr, 2018 6:43 pm

You need alot of water to fight a big bush fire. It is easier to 'fight fire with fire'.

Controlled hazard reduction burns make it easier, it creates "safer" areas with less fuel, making a major fire less likely to affect an area. Also in this age of technology it is vary easy for a person to skew the data they present to favour their argument, so unless it is peer reviewed be wary of the information presented.

Lastly, as a volunteer firefighter....I'll take controlled burns over major bushfires any day...after all, am I going to risk my life for the ill prepared home?
taipan821
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 168
Joined: Thu 16 Aug, 2012 8:49 pm
Region: Queensland
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby LachlanB » Fri 13 Apr, 2018 6:56 pm

taipan821 wrote:Controlled hazard reduction burns make it easier, it creates "safer" areas with less fuel, making a major fire less likely to affect an area.


When you get the major firestorms, like the Canberra 2003 fires, is the lower fuel load much of a factor? Doesn't the intense heat just sweep into the canopy, creating a crown fire that'll burn through anything?
LachlanB
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 363
Joined: Mon 21 Apr, 2014 5:07 pm
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby wildwanderer » Fri 13 Apr, 2018 7:03 pm

taipan821 wrote:You need alot of water to fight a big bush fire. It is easier to 'fight fire with fire'.

Controlled hazard reduction burns make it easier, it creates "safer" areas with less fuel, making a major fire less likely to affect an area.

Certainly in some cases. Although the study i referenced indicated that only 30% of burns (in the blue mnts during the study period) could be rated as effective burns. 40% were suboptimal and 30% made things worse.

taipan821 wrote:Also in this age of technology it is vary easy for a person to skew the data they present to favour their argument, so unless it is peer reviewed be wary of the information presented.

Very true. However the sources I presented are all from peer reviewed journals or a bushfire conference. Im sure there are also sources to be found that come to different conclusons.

Sources I referenced were.
Journal of biogeography
Library of the Parliament of Australia referencing work presented at Australian Bushfire Conference, Albury, July 1999.
Australian Medical Journal
User avatar
wildwanderer
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 997
Joined: Tue 02 May, 2017 8:42 am
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby rcaffin » Fri 13 Apr, 2018 7:30 pm

Often the fuel reduction is done to give you a fighting chance of stopping the fires WITH all those aids still in place,
Ho Ho Ho
Have you ever seen a Mainland firestorm? Let me be very plain: you have precisely ZERO chance of stopping a big fire. ZERO.

We had one whizz past us a few years ago - on the other side of the main road. It reached the Berowra Waters estuary and spotted straight across. Actually, it went over the top of quite a few properties on the way. About all you can do is try to protect the better-maintained houses.

Remember how they stopped the big Hobart fire, back in the 60s? The Army dynamited and bulldozed several ROWS of houses.

People die every year from the smoke from the control burns. Those burns do more harm than good.

Cheers
Roger
User avatar
rcaffin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 777
Joined: Thu 17 Jul, 2008 3:46 pm

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Fri 13 Apr, 2018 9:39 pm

Clearly not a fan of fuel reduction Roger so I wont try to convince you otherwise and yes, I have faced some big fires (but not on the mainland) and I agree, a very big fire you do have buckleys of stopping ....in certain conditions.
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Re: Bushfire hazard Reduction - worth it?

Postby taipan821 » Fri 13 Apr, 2018 9:49 pm

Wildwanderer:

Its interesting to read that the optimal burns were the minority, I've gone to conduct controlled burns and it's been sub-optimal, we normally just extinguish it and relight at another time. I can understand the 30% that turn into uncontrolled fires (the wonderful 'oh Sh**' moment when you rush for the hoses) but the 40% sub-optimal fires, I'll have to look into that. maybe there is something the local fire brigade can do to reduce that percentage.

Roger:
The chance of stopping a big fire by fighting it is not only zero it's nearly suicidal. big bushfires are stopped by containing them by lighting more fires (fight fire with fire) and creating areas of burnt ground in the bushfire's path (no fuel = no fire). If the homeowner doesn't maintain their home, its not savable and the firefighters (who often are volunteers) won't save them.

Hazard reduction burns are the pre-emptive move, as tastrax said hazard reduction burns gives the firefighters a chance of stopping the fire before it hits towns and communities. The goal is to minimise the fuel available for any bushfire.

But if you insist that they do nothing except kill people (I couldn't find it in the data, do we know what the 14 people in the report actually died from?)

http://www.bushfirecrc.com/sites/default/files/managed/resource/katherine-haynes.pdf
An interesting powerpoint....555 people and 123 firefighters have died due to bushfires. So it comes down to simple terms.

what's better? a few deaths and some cash for drip torch fuel? / many lives and property destroyed costing millions in response and rebuilding?

We're taught all life is precious...but we're also taught about acceptable losses. It's a horrible subject to delve into but it all comes down to best bang for the buck.
taipan821
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 168
Joined: Thu 16 Aug, 2012 8:49 pm
Region: Queensland
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Xplora » Sat 14 Apr, 2018 6:55 am

Fuel reduction burns in Vic are concentrating on areas around towns. The thought is to reduce fuel load so there may be a chance of stopping or slowing the fire before it reaches homes. Sometimes multiple fires start from lightning and when they join up as they did in 2003 the fire will be unstoppable but if the fire hits a lower fuel area then there may be a chance of preventing house and human loss.
Xplora
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1051
Joined: Sat 01 Aug, 2015 7:24 am
Region: Victoria
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby wildwanderer » Sat 14 Apr, 2018 7:47 am

taipan821 wrote:what's better? a few deaths and some cash for drip torch fuel? / many lives and property destroyed costing millions in response and rebuilding?
We're taught all life is precious...but we're also taught about acceptable losses. It's a horrible subject to delve into but it all comes down to best bang for the buck.


Xplora wrote:Fuel reduction burns in Vic are concentrating on areas around towns. The thought is to reduce fuel load so there may be a chance of stopping or slowing the fire before it reaches homes. Sometimes multiple fires start from lightning and when they join up as they did in 2003 the fire will be unstoppable but if the fire hits a lower fuel area then there may be a chance of preventing house and human loss.


This is exactly what spurred me to create this discussion. Im not convinced that bush fire hazard reduction does result in less harm or the best bang for our buck. I realise its difficult to say how many lives would be lost if we stopped hazard reduction burning. However, the doctors have told us how many people died as a result of just 6 days of hazard reduction burning.

Specifically that hazard reduction over a 6 day period caused 14 premature deaths, 29 cardiovascular hospitalisations and 58 respiratory hospitalisations. This is the evidence presented by doctors in one of the most respected medical journals in Australia advising that the deaths were attributable to smoke from hazard reduction burning.

Can we say that 6 days of hazard reduction burning will prevent more than 14 deaths and 87 hospitalisations?

If we can, then yes continue to do the hazard reduction burns but if we cant then its time to stop hazard reduction because its doing more harm than good.

If there is studies on estimated lives saved or injuries prevented because of preemptive hazard burning then Id be interested to read them. Im happy to revise an opinion based on evidence.
User avatar
wildwanderer
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 997
Joined: Tue 02 May, 2017 8:42 am
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Warin » Sat 14 Apr, 2018 8:12 am

wildwanderer wrote:Specifically that hazard reduction over a 6 day period caused 14 premature deaths, 29 cardiovascular hospitalisations and 58 respiratory hospitalisations. This is the evidence presented by doctors in one of the most respected medical journals in Australia advising that the deaths were attributable to smoke from hazard reduction burning.

Can we say that 6 days of hazard reduction burning will prevent more than 14 deaths and 87 hospitalisations?


Can we say that a real fire will not cause a similar number of added deaths from the fires added smoke if the hazard reduction burns had not taken place?

----------------------
There are many 'fire trails' that are not longer used to 'fight fires' with water .. they can be used to start back burns against a fire. There have been too many deaths of fire fighters on these 'fire trails' and the practice of there use has changed.

----------------
I'd like a hazard reduction burn at my place .. just to reduce the weeds and allow walking through the bush, as well as the increased ability to fight and fire.

I do think the burns should be over small areas adjacent to residential properties (where the flamin weeds come from). And that these should be far more frequent!
User avatar
Warin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 822
Joined: Sat 11 Nov, 2017 8:02 am
Region: New South Wales

Re: Bushfire hazard Reduction - worth it?

Postby wildwanderer » Sat 14 Apr, 2018 8:41 am

Warin wrote:Can we say that a real fire will not cause a similar number of added deaths from the fires added smoke if the hazard reduction burns had not taken place?


No idea. There is a fire so obviously there is still smoke. Is there less smoke due to a fuel reduction(not guaranteed) caused by previous hazard reduction burn in the same area? We would have to find a study that investigated it.
User avatar
wildwanderer
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 997
Joined: Tue 02 May, 2017 8:42 am
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Mark F » Sat 14 Apr, 2018 10:04 am

My understanding is that there are two aspects of fire in the environment - intensity and frequency. The aim of fuel reduction burning is to use low intensity fire to reduce fuel loads but the problem is that fuel loads rebuild very quickly - often the fuel load will be back to the same level with two or three years, potentially requiring another burn. Fire intensity determines whether individual species survive or perish and for much of the Australian bush plants have mechanisms to regenerate after fire but higher intensity fires place more species at risk of being unable to regenerate. Fire frequency plays a major role in the structure and floristics of the bush. Frequent fires will prevent many species from being able to replenish seed banks (on plant or in the soil) due to not reaching maturity before the next fire leading to their eventual extinction from the area. These plants will be replaced by species more adapted to fire and usually more flammable making the next fire more intense. It is not the single fire that causes the worst of this change but the limited time between fires.

For me very limited fuel reduction on the fringes of urban settlement is the least damaging option.
"Perfection is attained not when there is nothing more to add, but when there is nothing more to remove".
User avatar
Mark F
Lagarostrobos franklinii
Lagarostrobos franklinii
 
Posts: 2138
Joined: Mon 19 Sep, 2011 8:14 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Warin » Sat 14 Apr, 2018 10:18 am

wildwanderer wrote:
Warin wrote:Can we say that a real fire will not cause a similar number of added deaths from the fires added smoke if the hazard reduction burns had not taken place?

No idea.


Me neither. And I'd think it is not possible to get a 'correct answer' as there are too many variables .. in a 'real' fire the wind may well be higher - thus less smoke.

If these people are effected by smoke.. they may well be effected by pollution too and so have died from that, possibly a little later on.
------------
As for fire frequency and intensity .. there are few studies on it.
Unfortunately 'we' have lost a lot of experience with the loss of Aboriginal knowledge and practice.

Some of the plants need smoke and/or ash to regenerate too.
User avatar
Warin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 822
Joined: Sat 11 Nov, 2017 8:02 am
Region: New South Wales

Re: Bushfire hazard Reduction - worth it?

Postby Mark F » Sat 14 Apr, 2018 11:43 am

There were certainly several studies in good peer reviewed journals on the effect of fire on floristics when I studied the subject in the early 90's.

Yes - quite a few species require the leachate from smoke and ash to germinate. It is not the first fire that causes species loss but the second and subsequent fires if the inter-fire period is too short to allow the new plant to mature and produce viable seed.
"Perfection is attained not when there is nothing more to add, but when there is nothing more to remove".
User avatar
Mark F
Lagarostrobos franklinii
Lagarostrobos franklinii
 
Posts: 2138
Joined: Mon 19 Sep, 2011 8:14 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby rcaffin » Sat 14 Apr, 2018 7:52 pm

If you want to protect property, then clearing a fire break on the western side of housing makes some sense. But clear it in a sustainable manner - with a tritter (a huge slasher). This will eventually leave a wide grassy strip of native vegetation as a quite effective fire barrier. Part of our problem today is that Councils have let developers subdivide right to the edge of scarps so you can't have such barriers. Another part of the problem is that many home owners refuse to take any responsibility for protecting their house: they expect the RFS to do everything.

Yes, I am a bit hard-line here - having served my time in the local RFS and living in the bush. If YOU can't be bothered protecting your property, why should I risk my life to do that? And why should I bring so much distress to asthma sufferers just because you are lazy?

Mark's comment
It is not the single fire that causes the worst of this change but the limited time between fires.
is absolutely correct. Time for a change.

Cheers
Roger
User avatar
rcaffin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 777
Joined: Thu 17 Jul, 2008 3:46 pm

Re: Bushfire hazard Reduction - worth it?

Postby LachlanB » Sat 14 Apr, 2018 8:08 pm

Maybe a potential analogue here is stubble burning in the cropping lands out west?

It was originally a favoured management technique, but has become less prevalent recently.
Why?
Because the smoke from the burns was causing severe air quality problems, and had unfortunate environmental side-efects (erosion).

So now land managers are encouraged to use other techniques than stubble burning, to help reach the same goal. But stubble burning is still an option for farmers if they need to resort to it.


Maybe we just need to rethink the way that our communities and infrastructure interact with the bush? Pull fire-succeptible towns back into more compact communities, and cease the dispersed ridge-line developments that have caused so many problems in the Blue Mountains. Educate people more about bushfire risks, and encourage them to properly maintain their properties. Reduce hazard reduction burning to the immediate vicinity of communities, but build infrastructure around them to make sure that they can be easily protected.
LachlanB
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 363
Joined: Mon 21 Apr, 2014 5:07 pm
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Sat 14 Apr, 2018 9:16 pm

LachlanB wrote:Maybe we just need to rethink the way that our communities and infrastructure interact with the bush? Pull fire-succeptible towns back into more compact communities, and cease the dispersed ridge-line developments that have caused so many problems in the Blue Mountains. Educate people more about bushfire risks, and encourage them to properly maintain their properties. Reduce hazard reduction burning to the immediate vicinity of communities, but build infrastructure around them to make sure that they can be easily protected.


There is a lot to be said for much better planning of subdivisions etc that also include 'communal' open space, fire trails, emergency vehicle access etc etc

https://www.fire.tas.gov.au/publications/Bush_Guide.pdf
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Re: Bushfire hazard Reduction - worth it?

Postby LachlanB » Tue 17 Apr, 2018 10:05 am

Just read this online:
https://theconversation.com/contrary-to ... -age-95059
It's got a link to the recent paper supporting it.

Basically, the gist is that forests within the study area (Australian Alps) become less flammable directly after fire- because all the fuel has been consumed. Then they become more flammable because of regrowth, but once the forest matures (which can be as little as 14 years) it becomes dramatically less flammable.

I know it's talking about wildfires, rather than hazard reduction burns. However, the same logic could probably be extended to them, as hazard reduction burns spark the regrowth of the understory and encourage canopy regeneration. So, the burning would provide the greatest short term reduction in fire risk, but at the cost of increased long-term fire risk. Hence making repeat hazard reduction burns a necessity, if any burning is going to occur at all. But if we left forests to mature in the absence of fire, the long term fire risk would be decreased.

So why are we manually doing something that would otherwise be provided as an ecosystem service for free?
LachlanB
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 363
Joined: Mon 21 Apr, 2014 5:07 pm
Region: New South Wales
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby potato » Tue 17 Apr, 2018 11:10 am

In the literature that I have looked at and the academic fire ecologist I have worked with suggest that fire management is most effective closest to the asset. Sometimes that asset is ecological and at other times it has something to do with humans. What they are saying is - remove the flammable material from near the asset and build assets that are unlikely to go up in flames. If you build an asset in a high risk zone - have an evac plan. We live in Australia - fire is part of the landscape.

There is little evidence to suggest a 5,000w/m planned controlled fire, a ground fire, is a useful tool in preventing a 50,000 to 100,000w/m fire - a canopy fire. Its too simple a view about fire - a great Australian fire ecologist summarised fire as have four key components: fire needs a source of ignition, weather, terrain and fuel. You cannot control all of those and you cannot control how they interact to promote large landscape fires.

The management we see though is politically based fire management. The fire managers hire consultants and read scientific literature that suits their purpose so they can argue its effective fire management to burn hazard in the middle of nowhere. Some academics rely on being consultants to state agencies and therefore publish accordingly. This view of fire management allows managers to consume a budget so next year the same budget or a greater budget is allocated to that purpose. Politicians win as they can tell the people they are doing all they can and the fire manager win as their jobs are secure (some are former state foresters). I met a State Fire Commissioner once who said if he gave every household $10k to improve their individual fire preparedness, he could reduce the operating costs of the his fire service and have a greater chance of saving lives. He didn't fit in to the ideology of burning in that organisation and didn't last long.

I have a lot of respect for parks staff who it is their job to be a part of current fire management trend. A lot of them truly question the need to burn. They have a broader view that we don't understand a lot about the role of fire in the landscape and our burning is another layer of anthropogenic disturbance. In a few areas in this country, we have good traditional knowledge of how fire works in a landscape... however we cannot cut-and-paste that to every bit of landscape across the country as its simply not the case. This is especially true for eastern Australia, including the high country.
potato
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 256
Joined: Thu 28 Jan, 2016 1:06 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Tue 17 Apr, 2018 1:12 pm

I also chuckle when some people think a twenty metre firebreak between two patches of bush will be enough to protect their property! Of course the fire break always has to be on the crown land side of the fence and not the private property.

StopStop.JPG
StopStop.JPG (82.73 KiB) Viewed 5257 times
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Re: Bushfire hazard Reduction - worth it?

Postby potato » Tue 17 Apr, 2018 1:47 pm

Those dwellings have no chance.
potato
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 256
Joined: Thu 28 Jan, 2016 1:06 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Moondog55 » Tue 17 Apr, 2018 2:12 pm

potato wrote:Those dwellings have no chance.


That depends on how they are constructed and how well they are defended. Properly built to the new code and with enough water for suppression I don't see a real problem. I see the problem as people not knowing the real risks or failing to take the training to minimise these risks.
A firebrak needs to be twice the width of the tallest tree or pole on the boundary edge, of course a 20 metre firebreak won't work if you have a 30 metre bloodwood on each side but it is plenty for a medium size grass fire. In Canada they build the fire breaks a mile wide and sometimes even that isn't enough but the Canucks don't use preventative control fires either
Ve are too soon old und too late schmart
Moondog55
Lagarostrobos franklinii
Lagarostrobos franklinii
 
Posts: 9151
Joined: Thu 03 Dec, 2009 4:15 pm
Location: Norlane Geelong Victoria Australia
Region: Victoria
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Warin » Tue 17 Apr, 2018 2:38 pm

In NSW you can only clear (everthing, trees, shrubs etc) 10 meters from the house! Then only clear shrubs (not trees) for 50 meters from the house... that is if the area is owned by you.
https://www.rfs.nsw.gov.au/plan-and-pre ... n-clearing

There is a wooden church in Ferntree Hobart that is surrounded by trees .. and survived the Hobart fires in '67. Yet a sandstone building further north with less trees burnt to the ground.

Tastrax those homes would have to have a BAL rating of FZ (Fire Zone) - would probably have to have automatic external fire rated shutters etc etc ... if built today. Certainly they would cost a lot more .. and a fair bit less if cleared for 10 m around them.
https://www.rfs.nsw.gov.au/plan-and-pre ... and-design
Last edited by Warin on Tue 17 Apr, 2018 3:48 pm, edited 1 time in total.
User avatar
Warin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 822
Joined: Sat 11 Nov, 2017 8:02 am
Region: New South Wales

Re: Bushfire hazard Reduction - worth it?

Postby potato » Tue 17 Apr, 2018 3:14 pm

Moondog55 wrote:
potato wrote:Those dwellings have no chance.


That depends on how they are constructed and how well they are defended. Properly built to the new code and with enough water for suppression I don't see a real problem. I see the problem as people not knowing the real risks or failing to take the training to minimise these risks.
A firebrak needs to be twice the width of the tallest tree or pole on the boundary edge, of course a 20 metre firebreak won't work if you have a 30 metre bloodwood on each side but it is plenty for a medium size grass fire. In Canada they build the fire breaks a mile wide and sometimes even that isn't enough but the Canucks don't use preventative control fires either


Yep but even a well designed fire break will do nothing under the right conditions. Paddocks hundreds of metres wide and grazed bare to the ground burnt across parts of NSW and the ACT in 2003. Fire is much more complex than fuel alone.

So it comes back to - is hazard reduction worth it? Not really.
potato
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 256
Joined: Thu 28 Jan, 2016 1:06 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Moondog55 » Tue 17 Apr, 2018 3:45 pm

Totally disagree
Hazard reduction is always worth it, and controlled fires small and often are part of it.
We don't burn often enough and we tend to burn in the wrong places at the moment
Ve are too soon old und too late schmart
Moondog55
Lagarostrobos franklinii
Lagarostrobos franklinii
 
Posts: 9151
Joined: Thu 03 Dec, 2009 4:15 pm
Location: Norlane Geelong Victoria Australia
Region: Victoria
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby Warin » Tue 17 Apr, 2018 3:57 pm

potato wrote:Yep but even a well designed fire break will do nothing under the right conditions. Paddocks hundreds of metres wide and grazed bare to the ground burnt across parts of NSW and the ACT in 2003. Fire is much more complex than fuel alone.

Disagree.
A MANNED fire brake (of sufficient width to keep the workers safe, and with enough people) will protect adjacent buildings. The buildings have to be able to withstand ember attack.
potato wrote:So it comes back to - is hazard reduction worth it? Not really.

Depends.
What it the rate of;
hazard generation (to some level)
hazard reduction frequency (reduced to some level, and at some height)
etc...

Too many variables to have a general rule. So there can be no single answer.
User avatar
Warin
Phyllocladus aspleniifolius
Phyllocladus aspleniifolius
 
Posts: 822
Joined: Sat 11 Nov, 2017 8:02 am
Region: New South Wales

Re: Bushfire hazard Reduction - worth it?

Postby potato » Tue 17 Apr, 2018 4:05 pm

Show me the evidence, the actual science that hazard reduction works.
potato
Athrotaxis cupressoides
Athrotaxis cupressoides
 
Posts: 256
Joined: Thu 28 Jan, 2016 1:06 pm
Region: Australian Capital Territory
Gender: Male

Re: Bushfire hazard Reduction - worth it?

Postby tastrax » Tue 17 Apr, 2018 5:03 pm

What is your criteria for 'works'? Stops a low grass fire with no wind on the flat or stops a crown fire on a 30 degree slope in 100kmh wind with air temps at 40 degrees?

Or maybe its that it attains the required specification of the burn - ie 80% of fuels to a height of X are removed across 80% of the area ....or some such specification
Cheers - Phil

OSM Mapper
User avatar
tastrax
Athrotaxis selaginoides
Athrotaxis selaginoides
 
Posts: 1738
Joined: Fri 28 Mar, 2008 6:25 pm
Location: What3words - epic.constable.downplayed
ASSOCIATED ORGANISATIONS: RETIRED! - Parks and Wildlife Service
Region: Tasmania

Next

Return to Bushwalking Discussion

Who is online

Users browsing this forum: No registered users and 4 guests