Bushfires - Burning for the better

Essay by bully_bobHigh School, 11th gradeB+, August 2008

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Lachlan Bryant Biology Mrs Davies


Bushfires have played a vital role in the up keeping of the Australian bush for millions of years. Much of our vegetation has evolved with fire. Like the vegetation in other harsh and dry environments, it has developed characteristics that promote the spread of fire and in some cases, fire is essential in the reproduction of some native flora (CSIRO). In the Bunya Mountains, recent study has shown that lack of fire has dramatically accelerated the decrease of the number and size of grasslands in the Bunya Mountains which are called balds (NLWRA). This brings to question why there is such an opposition to controlled burning of areas such as the Bunya Mountains when in fact not putting to use controlled burns potentially has a far worse effect than burning.

Fire has intense effects on the abiotic factors of forest ecosystems.

Surface temperatures have been reported to reach 1,000°C (Ahlgren) and a number of physicochemical properties of the soil are affected. Severe heating of soil breaks down the structures of the inorganic parent materials, causing the soil structure to become unstable (Ulery). Fire creates layers within the soil that are resistant to water which decreases water infiltration and increasing soil erosion by water runoff (Amlendros, DeBano).

The effects on ammonium and nitrate concentrations are variable (Covington, Jorgensen, Kovaci), while concentrations of phosphorus, potassium, and magnesium are reported to increase (D.W Smith).

Due to the release of basic cations during combustion and their deposition on the surface of the soil, most studies declare an increase in soil PH after fires (Pietikäinen, T.H Anderson).

Natural forests and their ecosystems in Australia have evolved to use available rainfall in a way that allows them to survive. In each climate niche, naturally and man...