Bushfire basics

History of bushfires

Bushfires / Wild Fires are a natural part of wildland renewal in Australia and they have existed for as long as trees and combustible plants have been around. While typical for Australia, bushfires occur in many places around the world where there is plenty of fuel; wood, leaves, forest or brush, that can burn.

After the settlement of Australia by Europeans, the nature of wildfires (fires that burn in the wild) has changed. The aboriginals used wildfires to cultivate the land, and it was a natural part of regeneration of the bush. Prior to settlement, bushfires were typically mildfires – fires that burn in a relatively low intensity and don't spread as fast or a far as many of the modern bushfires. This is because fires were frequent, and there was no accumulation of excess fuel in the ground.

However, the new settlers were determined to make the land work for them, instead of working with the land. Excessive clearing and a wasteful use of cleared timber caused massive accumulation of fuel ready to be burned, irresponsible land management and the formation of urban-wildlife interface created circumstances that were just right for intense wildfires to occur. In fact, because the nature of wildfires has changed, the flora of bushland has changed as well.

How do they get started?

A staggering 94% of bushfires are started by humans. About half of these are a result of a burn-off that gets out of hand, and an increasing number are started by arson, firebugs. Other man-made reasons include spot fires caused by burning embers being blown away from buildings already burning, sparks from power lines, sparks from mechanical sources, cigarette butts thrown out of cars, camp fires, etc.

Lightning is the greatest cause of bushfires in Western Australia, Northern Territory and western Queensland, due to the number of electric storms that take place during summer. Other natural causes for bushfires are spot fires from already burning fires, friction of trees and spontanous combustion.

You would have noticed the word “spot fire” in the previous paragraphs. The concept of spot fire is extremely important in understanding bushfires. A spot fire is caused by burning embers being blown away by high winds that occur during bushfires. The embers will ignite other combustible material ahead of the approaching fire front thereby helping the fire to spread. Depending on the type of fire, fuel and weather conditions, spot fires can start up to 25 kilometers or more from the firefront!