The Impact of Fire on Biodiversity托福红Delta听力原文翻译及问题答案

The Impact of Fire on Biodiversity托福红Delta听力原文翻译及问题答案， 今天中国教育在线就来为大家分析这个问题。

一、The Impact of Fire on Biodiversity 托福听力原文：

We all know that change is a fact of life. For North American forests, change often comes in the form of fire. After thousands of years of living with fire, many plant and animal species have come to depend on its periodic presence. Without fire, ecosystems can stagnate and lose their diversity of life.

In the past, before we understood the role that fire plays in the natural life cycle of our forests, our goal was to prevent or contain all forest fires. For almost ninety years, our land management agencies tried to eliminate fires. In many cases, we protected the trees, but at the expense of the forest community. Now we know that fire is a natural agent that rejuvenates a forest. And we know that fire suppression can actually threaten the lives of healthy trees. So, today our policy is to allow natural fires to burn under close observation and to set “prescribed” fires under carefully controlled conditions.

Research shows that forests go through natural fire cycles. Periodic fires are necessary for several reasons. Fire removes nutrients from standing dead trees and returns them to the earth, where they become available to the root systems of new trees. Fire also opens the forest to sunlight. Openings in the tree cover benefit a variety of wildlife by stimulating the growth of lush green plants, which are eaten by several species of animals.

Fire is nature’s way of controlling insect infestations. By contrast, fire suppression preserves dead wood that harbors insect pests, like the larvae of the mountain pine beetle. These beetle larvae feed on the inner bark of some trees, which blocks the flow of nutrients and eventually kills the trees. When dead trees burn during periodic outbreaks of fire, the heat kills off great numbers of beetles and larvae, providing a natural method of pest control.

The exclusion of fire from the ecosystem is creating unhealthy, overcrowded forests that contain more fuel for larger, more severe fires. For example, when a huge fire threatened a grove of giant sequoias in California, observers noted that the flames were fed by dead wood and combustible debris that had accumulated on the forest floor over years of fire suppression.

A large-scale, intense forest fire causes more significant impacts to water, soil, and air resources than a managed prescribed fire. Prescribed fire, or controlled fire, has several purposes. Chiefly, it reduces the hazard of more serious wildfires by periodically burning accumulated weeds, brush, and other plants. If done carefully, prescribed burning also releases nutrients back into the soil and controls insect pests.

In Florida, prescribed burns are carried out every three to five years in one of the national forests. These controlled burns keep the forest open and reduce the growth of problem species.

We recognize that fire is a natural and revitalizing process that enhances the diversity of the forest. However, we also know that fire has consequences. There may be smoky, hazy skies and patches of blackened forest for a long time after a fire. There’s also the risk of a fire becoming too large and threatening inhabited areas. But we have to accept these realities if our forests are to retain their ecological balance.

二、The Impact of Fire on Biodiversity 托福听力中文翻译：

我们都知道改变是生活的一个事实。对于北美森林来说，变化往往以火的形式出现。在与火共存数千年之后，许多动植物物种已经开始依赖火的周期性存在。没有火，生态系统就会停滞，失去生命的多样性。

过去，在我们了解火灾在森林自然生命周期中所起的作用之前，我们的目标是预防或控制所有森林火灾。近90年来，我们的土地管理机构一直在努力扑灭火灾。在许多情况下，我们保护了树木，但以牺牲森林社区为代价。现在我们知道火是一种天然的媒介，可以使森林恢复活力。我们知道，灭火实际上会威胁健康树木的生命。因此，今天我们的政策是允许自然火灾在密切观察下燃烧，并在精心控制的条件下设置“规定”的火灾。

研究表明，森林经历了自然火灾循环。有几个原因需要定期火灾。火从枯死的树木中去除养分，并将其返回地球，在那里新树木的根系可以利用这些养分。火还使森林向阳光开放。树木覆盖层的开口通过刺激郁郁葱葱的绿色植物的生长，使多种野生动物受益，这些植物被多种动物吃掉。

火是大自然控制虫害的方式。相比之下，灭火可以保护藏匿害虫的枯木，比如山松甲虫的幼虫。这些甲虫幼虫以一些树木的内部树皮为食，这会阻碍养分的流动，最终杀死树木。当枯树在周期性的火灾中燃烧时，高温杀死了大量的甲虫和幼虫，提供了一种自然的害虫控制方法。

将火排除在生态系统之外正在造成不健康、过度拥挤的森林，为更大、更严重的火灾提供更多燃料。例如，当一场大火威胁到加利福尼亚州一片巨大的红杉林时，观察家们注意到，大火是由多年灭火后堆积在森林地面上的枯木和可燃碎片引发的。

大规模、强烈的森林火灾对水、土壤和空气资源的影响比管理规定的火灾更大。规定火灾或控制火灾有多种用途。主要是，它通过定期焚烧积累的杂草、灌木丛和其他植物来减少更严重野火的危害。如果小心地进行，规定的焚烧也会将养分释放回土壤中，并控制害虫。

在佛罗里达州，每三到五年在一片国家森林中进行一次规定的焚烧。这些受控的燃烧保持了森林的开放性，减少了问题物种的生长。

我们认识到，火灾是一个自然和恢复活力的过程，它增强了森林的多样性。然而，我们也知道火灾有其后果。火灾发生后很长一段时间内，可能会有烟雾弥漫的天空和大片发黑的森林。还有火灾变得太大并威胁居住区的风险。但是，如果我们的森林要保持生态平衡，我们就必须接受这些现实。

三、The Impact of Fire on Biodiversity 托福听力问题：

Q1:

What is the main idea of the talk?

A.Forest management agencies have eliminated forest fire.

B.Fire contributes to the beauty and mystery of the forest.

C.Fire revitalizes the forest and promotes a diversity of life.

D.Forest fire limits the amount of habitat taken by humans.

Q2:

What does the instructor mean by this statement:

A.Fire prevention has actually damaged the forest ecosystem.

B.Every tree in the forest passes through its own life cycle.

C.Protecting one species will benefit every other species.

D.Foresters will never fully understand the laws of nature.

Q3:

According to the instructor,why is periodic fire necessary to forest ecosystems?

Click on two answers.

A.Fire releases nutrients into the soil.

B.Fire creates employment for firefighters.

C.Fire controls insect pests that harm trees.

D.Fire reduces water and air pollution.

Q4:

According to the instructor,how does the elimination of fire endanger the forest?

A.Insect populations die without the heat provided by fire.

B.Dead wood and litter accumulate as fuel for large fires.

C.Too many people move into the forest,destroying wildlife habitat.

D.Animal populations grow too fast for the forest to support them.

Q5:

What is prescribed fire?

A.Fire that is caused by lightning

B.Fire that humans carefully manage

C.Fire that inspires artists and writers

D.Fire in areas where people live

Q6:

Why does the instructor say this:

A.To explain why good firefighters are needed

B.To tell about his own observation of a large fire

C.To find out if students have ever seen a fire

D.To give examples of the negative effects of fire

四、The Impact of Fire on Biodiversity 托福听力答案：

A1:正确答案：C

A2:正确答案：A

A3:正确答案：AC

A4:正确答案：B

A5:正确答案：B

A6:正确答案：D

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