Bush Fire

Bush fires are a common event in Australia and they burn though natural vegetation, plantations and towns. Some are lit accidentally by humans while others are lit on purpose by arsonists. Other bush fires are caused by lightning strikes. Evidence suggests that natural fires have been affecting ecosystems in Australia for over 40 million years, while humans have probably only lived here for around 40,000 years.

Fire has a major impact on ecosystems in Australia because it promotes the germination of many plant species. After a fire, much of the bush regenerates through germination. Many plants are adapted to survive fires and even benefit from fire. Plants such as banksias and hakeas need fire to allow their seed cases to open and release the seeds. Grass trees and some orchids flower after a fire.

Eucalypts have oils in their leaves that catch fire easily. Some also have 'stringy' bark that hang down to the ground, as in. There is a lot of plant litter that falls to the ground, such as dead leaves and bark. These may seem like strange features for a plant to have in an area where bush fires occur.

However, helping a fire to spread probably provides an advantage to eucalypts. After a fire, eucalypts can quickly regenerate, whereas other plants may not. This gives eucalypts a competitive advantage in fire-prone areas.

Eucalypts are adapted to survive fires in several ways. Thick bark insulates the living cells beneath it against the heat to the fire and so keeps the growing part of the trunk and branches alive. After a fire, new growth sprouts from the trunk and branches. All the leaves may have died, so new ones must grow to allow the plant to begin photosynthesizing again. This growth is known as epicormic growth. The new growth of shoots allows the plants to quickly produce food and gain an advantage over other plant species that were liked and rely on seeds to regenerate.

Some eucalypt species called mallees have lignotubers. Lignotubers are swollen stems under the ground. The branches above the ground may have died in the fire, but those below ground are insulated from the heat and quickly sprout after a fire.

The effects of fire on animals vary. Slow-moving animals that cannot escape fires by burrowing or migrating may be killed. The dead are replaced by surrounding population expanding back into the burnt-out area after the fire. Fire promotes the growth of fresh shoots that are highly nutritious for herbivores, which therefore benefit from the fire.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

Which of the following Australian plants flower after a fire?
A. Grass trees	B. Coniferous trees	C. Orchids	D. Both A and C
Right Option : D
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Question : 2

The main reason of bushfires is _________________.
A. Lightning strike	B. Flooding	C. Volcanoes	D. None of the above
Right Option : A
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Question : 3

Regrowing of a shoot from a dormant bud under the bark is known as ______________.
A. Endocormic growth	B. Epicormic growth	C. Hypocormic growth	D. None of the above
Right Option : B
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