Bushfire in Australia
50,000 years ago, central Australia was covered in forests and inhabited by tree-dwelling kangaroos, and herbivores the size of a rhinos. Furthermore, salt-pans like Lake Eyre were deep water lakes that were continually replenished by annual monsoons.
The change from a productive and fertile environment to an arid wasteland came about due to humans intentionally burning the bush. By intentionally burning the bush, humans altered the exchange of water vapour between the biosphere and atmosphere. Clouds stopped forming and the annual monsoon over central Australia failed. As vegetation continued to decline, so too did the ability of the environment to recycle rainfall. In forests like the Amazon, 50 per cent of rainfall gets recycled by the ecosystem. Rain falls, is trapped, sucked up by trees, released into the atmosphere, reaches a critical humidity and then falls again at a different location. In Australia; however, after the foliage was razed to the ground, rain fell and soaked into the sand or quickly evaporated under the scorching sun.
Today, the environment is still being burnt, and still suffering as a consequence. One reason for the burning is a misguided belief that because the large herbivores are extinct, the foliage that they used to eat needs to be burnt otherwise it may result in severe bushfires that will harm the ecosystem and destroy houses. This belief was popularised by Dr Tim Flannery, the 2007 Australian of the Year. According to Flannery,
"The Australian landscape was changed by the impact of huge uncontrolled fires - a direct consequence of the build up of uneaten vegetation, following the demise of the megafauna."
It has to be said, Flannery is an idiot, and has been rightly labelled as such by his peers. Most animals don't like eucalypts that dominate after bushfires, and are prone to sit as fuel. Animals like lush trees that do not easily go up in flames, and are usually killed off by bushfires. Lush trees decompose relatively quickly and the return of their nutrients to the soil provides food for more lush trees. Furthermore, by shading the ground and locking moisture into the ecosystem, lush trees facilitate the decomposition process.
As for the need to reduce uncontrollable bushfires that could destroy housing, a far easier solution would simply to design bushfire-proof housing, or plant lush trees that do not burn as easily as eucalypts.
Another reason to burn the bush is to pay homage to Aboriginal cultures. Aboriginality is to some Australian "scientists" what intelligent design is to some American scientists. According to some Australian scientists, Aborigines were in harmony with the land and their cultural practices need to be accepted as gospel. One "scientist" who has embraced the gospel is David Bowman, an ecology "expert" from Charles Darwin University. According to Bowman:
"They intervened and they changed the habitat balance with their fire management practices and, in doing so conserved some habitats, such as rainforest, that might otherwise have been lost during the extreme aridity that characterised the end of the last ice-age some 10,000 to 20,000 years ago."
By Bowman's logic, a flame thrower should be the solution to global warming. Those who worry about rainforests turning to desert shouldn't waste their time reducing their carbon footprint. Instead, they should just throw their cigarette butts out the window.
Ironically, some "scientists" have in fact argued that, as well as preserving the ecosystem, burning the bush will actually reduce the amount of CO2 emissions that cause global warming. One of these is CSIRO research scientist Dick Williams. According to Williams, if an ecosystem is burnt, then it won’t suffer extreme bushfires in the future. Therefore, paying people to burn the bush should be seen as a form of carbon trading. American gas company ConocoPhillips agrees, and is now paying people in West Arnhem land $1 million a year, for 17 years, to offset 100,000 tons of the refinery's own greenhouse emissions. If Williams’ logic were extended, if a tank of petrol is burnt over three months it will release less CO2 than a tank that is burnt in a single day. If so, perhaps a form of carbon trading can be to buy petrol and then slowly burn it off. Furthermore, clear-felling forests should also be a form of carbon trading beause it too reduces the threat of bushfires.
Contrary to what the "scientists" believe, intentionally lighting a fire only reduces the threat of more bushfires in that it reduces the productivity of the Australian land.
If the ecosystem is not burnt to the point of collapse, the bushfire actually increases the risk of another bushfire. As the native plants that survive have a comparatively strong ability to recover from bushfires, they have evolved to encourage bushfires so that they can maintain their dominance. As a result, the Australian ecosystem is dominated by oil rich eucalypts that dominate over lush vegetation that decomposes quickly, is enjoyed by animals and does not easily burn.
Hot burn or cold burn?
Environmental pyromaniacs make a distinction between "hot" burns that occur naturally, and the "cold" burns controlled by humans. The hot burns are the uncontrollable infernos that are often started by lightening strikes in the Australian summer. The cold burns are started by humans, and aim to increase biodiversity and reduce fuel load. In a cold burn, most of the small bushes and grass is burnt, but the trees survive. In theory, as long as the land is burnt in patches, each section will have a slightly different ecosystem and overall biodiversity will increase.
The validity of the theory can be tested by contrasting the natural "hot" burn that followed the 2003 firestorm in the Brindabella Ranges surrounding Canberra and the "cold" burns around Canberra suburbs designed to increase biodiversity and reduce the bushfire threat.
Hot burns in the Brindabella Ranges
The deceptive nature of recovery
Many people have a misconception that fire magically infuses water and nutrients that stimulate plant growth. Perhaps their misconception stems from the appearance of the bush after a fire. On a superficial level, it looks like the ecosystem has benefited. There is an explosion of greenery as trees regrow and seeds germinate. Looks; however, are deceiving. The explosion of greenery is nothing more than plants using weakness in the ecosystem as the opportune time to push for individual dominance. These explosions use the plant's energy reserves, and most of the new plants will eventually die. If another fire came through, the explosion of greenery would be less. If too many fires came through, the ecosystem would collapse.
Build up of fuel after a bushfire
After the 2003 firestorm that threatened Canberra houses, the ACT Government established the McLeod Inquiry to report on how the fires could have been avoided, and homes saved. The inquiry blamed the government for not reducing the build up of fuel with periodic burning.
Like many government reports that have shaped Canberra into anything but a world renowned city, the report was flawed. Aside from the fact that it is more economical to build a bushfire-resistant house than constantly burning the bush, a bushfire can increase fuel load. A natural bushfire burns hot, but it burns for a short time. The above photo shows small branches that were killed by the fire, but not consumed by it. These branches are now potential fuel for another fire.
Periodic burning of the bush only reduces the threat of fire by reducing the productive capacity of the Australian land. If reducing productive capacity is the aim, then poisoning plants or clear felling could also achieve the aim, and achieve it more economically.
Cold burns in Canberra reserves
The Black Mountain Reserve in central Canberra and the semi-native backyard gardens on the Reserve's outskirts provide a useful contrast between two ecosystems shaped by human intervention over the last 40 years. In one ecosystem, humans intervene by burning it. In the adjoining ecosystems, humans intervene by adding water, diverse plant species and fertiliser.
Since stage 3 water restrictions were implemented in 2003, the amount of water the gardens have received is roughly similar to the native reserve. The productive capacity of the gardens is far greater than that of the native bush. Furthermore, despite never being burnt, the gardens are far less likely to go up in flames than is the dry reserve that is constantly burnt. Finally, native fauna seem to prefer the gardens to their reserves.
Cold burns - towards collapse
The aftermath of a cold burn in the Black Mountain Reserve in central Canberra. Some of the tussocks have been burnt one too many times, and have died. Decaying plant matter has been burnt, and much of the ash has washed away. The top soil is only a few millimeters thick. The ground is rock hard, and relatively exposed to the scorching sun. Rain falls on the rock hard earth, flows away or quickly evaporates. With few low level bushes, very little moisture is trapped in the ecosystem and the decomposition process is very slow.
Cold burn - Eucalypts but not much else
The aftermath of a cold burn in the Black Mountain Reserve in central Canberra. Trees are blackened, but survive. Despite the intended aim of reducing fuel load, dead branches and oil rich leaves are still potential fire hazards. Native fauna is almost non-existent.
Non-burnt bushland
Bushland in the Black Mountain Reserve that has not been burnt for the last 20 years. Top soil is an inch thick, but still not overely fertile. Despite the unburnt areas having more grass cover, the fire danger between the burnt and unburnt areas is roughly similar.
Semi-native garden in adjoining suburb
Biodiverse ecosystems in backyards have been rebuilt with fertiliser, and water over the last 40 years. Since water restrictions were introduced in 2003, the ecosystems have received comparable water inputs to the bushland.
In the above photo, the top soil is up to 10 inches thick, and plant matter decomposses quickly in the shade provided by bushes. Lush fruit trees thrive. Not only are they enjoyed by possums, they also reduce the bushfire threat. They do not not easily go up in flames, they decompose quickly, and they can trap embers blowing in the wind.
Native fauna prefer people's backyards to their charred reserves
Lizards, rosellas, possums, snakes, and owls put up with the threat of cats, dogs and poisoned insects in order to reap the benefits of the gardens.
