With credit to the ABC the above image is taken from the introduction to its television documentary found on iView:
“Can the traumatised survivors of a bushfire-ravaged coastal community seize control of their own destiny, overcome their differences, and save their town from dying?”
Raising giants
A recent ABC story on “desperate efforts to regenerate Victoria’s towering ash forests, which are being regularly decimated by bushfires, involves a dedicated group searching high and low to bank enough seeds for their survival.”
The story is essentially about harvesting tiny Mountain Ash seeds to sow vast areas of Victoria’s bushfire-devastated High Country:
“The seeds are being collected, stored and one day will be sown in a bid to keep Victoria’s alpine and mountain ash forests alive for future generations.”
A degree in ‘rocket science’ is not required to identify the reason for this seed collection, clearly it is due to extremely poor forest management that is lack of fuel (vegetation) management, the results of which are quite evident in the landscape scale photos included in that part of the story headed “Ash forests to forests of ash” — “The fires impacted around 88,000 hectares of ash forest, killing 25,000 hectares of young ash trees.”
The High Country is no stranger to devastating bushfires as these photos of earlier destruction of Snow Gums south of Mount Hotham reveal.
Photo: Nicholson 2014
Photo: Nicholson 2018
And again considering the devastation revealed in the two landscape-size photographs under the heading “Ash forests to forests of ash” in the ABC story, what was the impact of the fire on native birds, animals and marine life?
How many possibly rare and endangered native fish are gasping their last in that video?
Climate change or global warming
Climate change or global warming and its effect on bushfire in the forest? First, there is one constant and that’s the temperature of burning vegetation otherwise known as cellulose. The Executive Summary for the paper Project Vesta Fire in Dry Eucalypt Forest: Fuel structure, fuel dynamics and fire behaviour Gould, McCaw, Cheney, Ellis, Knight and Sullivan informs that:
“A model to predict flame height from rate of spread and elevated fuel height has been developed to better describe suppression difficulty and to facilitate the prediction of maximum spotting distance. Tall bushfire flames can reach a maximum temperature of 1000ºC to 1100ºC at the base of the flaming zone“.
“and, when observation height was normalised by flame height, flame temperature exponentially decreased to the visible flame tip where temperatures were ~300°C.” according to Flame temperature and residence time of fires in dry eucalypt forest Wotton, Gould, McCaw, Cheney and Taylor.
Here’s an interesting fact to consider when thinking about bushfire, the temperature at the burning tip of a cigarette during ‘puffs’ or drawing is widely considered to be about 900ºC — well above the flame tip temperature of a bushfire.
Photo: Stoios
Fire intensity
What then causes bushfires to exhibit the intensity of a fire approaching Wye River on Christmas Day 2015?
Unlike the flaming end of a cigarette a bushfire in forest has vastly more fuel available to contribute to the the ‘intensity’ of the fire — “Fire intensity is the amount of energy or heat given off by a forest fire at a specific point in time.” Fire intensity is measured in kilowatts per unit length of the fireline (kW/m) The more fuel available the more intense the fire
An easy to understand illustration on fire intensity below — click on the Source to open a broader explanation.
Imagine how many cigarettes it would take to create a convection column like the late afternoon column above Bairnsdale on 30 December 2019.
There should be no doubt that the devastation bushfire causes to the National Estate and recognition that the solution is to manage the fuel that contributes significantly to ignition and spread of bushfire. All that prolonged drought does is to over time dry the heavier fuels that in turn contribute to the fire load. And that’s manageable:
Hence the cigarette analogy, used properly a small fire of kindling sized fuel that does not generate sufficient kilowatts to harm the fingers holding it. Properly done, fuel reduction burning is intended to be done in a manner to consume the kindling size fuel to prevent the heavier fuels being ignited.
People’s Republic of Mallacoota
“Can the traumatised survivors of a bushfire-ravaged coastal community seize control of their own destiny, overcome their differences, and save their town from dying?”
View ABC’s “People’s Republic of Mallacoota here.
Fire severity
“Fire severity refers to the effects of a fire on the environment, typically focusing on the loss of vegetation both above ground and below ground but also including soil impacts.”
View a simple explanation of fire severity here.
And again considering the devastation revealed in the two landscape-size photographs under the heading “Ash forests to forests of ash” in the ABC story , the photo above “high severity” in the preceding well describes the flora and fauna damage being address by the seed collectors. But at what dollar cost that could have been avoided with better forest management?
And there are aspects of the impact of bushfire that also determine severity such as:
- loss of human life, be it immediate or some time later
- trauma induced mental health issues
- a home or business
- loss of community amenity
- interference with community lifelines
impact beyond the bush e.g. difficulty reestablishing in settled areas affected, planning restrictions, cost of insurance.
Then there’s the massive impact of carbon release and its deleterious impact on global warming, and finally
Vulnerablity of unprotected forest to a hostile power weaponising bushfire.
