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发表于 2016-7-11 17:56:45
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Passage 2
When in Australia recently, I visited a eucalyptus forest that was once the
scene of an appalling wildfire. Perhaps naively, I had expected to find that
many trees had been killed .They hadn’t. They had blackened bark, but were
otherwise looking rather well, many of them wreathed in new young leaves. This
prompted me to consider fire and the role it plays as a force of nature.
Fossil charcoals tell us that wildfires have been part of life on the earth
for as long as there have been plants on land. Fire was here long before such
plants as grasses; it predated the first flowers. And without wanting to get
mystical about it, fire is ,in many respects , a kind of animal, albeit an
ethereal one .Like any animal, it consumes oxygen .Like a sheep, it eats plants.
Sometimes, it merely nibbles a few leaves; sometimes it kills grown trees.
Sometimes it is more deadly and destructive than a swarm of locusts.
The shape-shifting nature of fire makes it hard to study. Some fires are
infernally hot; others, relatively cool. Some stay at ground level; others climb
trees. Moreover, fire is much more likely to appear in some parts of the world
than in others. Satellite images of the earth show that wildfires are rare in,
say, Northern Europe, and common in parts of Central Africa and Australia.
Once a fire gets started, many factors contribute to how it will behave.
The weather obviously has a huge effect: winds can fan flames, rains can quench
them. The lie of the land matters, too: fire runs uphill more readily than it
goes down. But another crucial factor is what type of plants the fire has to
eat.
It’s common knowledge that plants regularly exposed to fire tend to have
features that help them cope with it, such as thick bark, or seeds that only
grow after being exposed to intense heat or smoke.
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