首页
登录
职称英语
Forestry Forest Fire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img] [br] What
Forestry Forest Fire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img] [br] What
游客
2025-02-08
10
管理
问题
Forestry Forest Fire
[br] What is prescribed fire?
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.
选项
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
答案
B
解析
What is prescribed fire?
The instructor says Prescribed fire, or controlled fire...; ...prescribed burns are carried out every three to five years in one of the national forests. These controlled burns....(2.2)
转载请注明原文地址:https://www.tihaiku.com/zcyy/3948507.html
相关试题推荐
Philosophy[img]2012q1/ct_etoefm_etoeflistz_0212_20121[/img][br]Withwhichphil
Philosophy[img]2012q1/ct_etoefm_etoeflistz_0212_20121[/img][br]Listenagainto
Philosophy[img]2012q1/ct_etoefm_etoeflistz_0212_20121[/img][br]Whichofthefo
ConversationLearningResourceCenter[img]2012q1/ct_etoefm_etoeflistz_0206_20121
ConversationLearningResourceCenter[img]2012q1/ct_etoefm_etoeflistz_0206_20121
ForestryForestFire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img][br]Whyd
ForestryForestFire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img][br]What
ForestryForestFire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img][br]Accor
ForestryForestFire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img][br]Accor
ForestryForestFire[img]2012q1/ct_etoefm_etoeflistz_0199_20121[/img][br]Liste
随机试题
Musicwhichis【B1】______isindividualandpersonal.Thatistosay,itcanb
[originaltext](16)Itiswhatfaileddietershavelongsuspected:Fatpeopl
A.accordinglyB.accountsC.allowanceD.benefitsE.budgets
斯坦利?米尔格莱姆经典的“电击实验”用来研究()A.说服 B.服从 C.攻击
初步设计完成后,设计项目比选时采用的建筑工程单方造价一般是指( )。A.工程概
郑某今年12周岁,父母双亡,有一套自己的房屋,现因出国求学需将其出售,所在地居民
肾脏疾病发生尿路刺激征常见的原因是A.肾盂受刺激 B.输尿管受刺激 C.肾小
90.1946年8月,毛泽东在同美国记者安娜·路易斯·斯特朗的谈话中 提出
许又新提出心理健康的标准衡量不包括( )。A.计算标准 B.体验标准
三羧酸循环中草酰乙酸的来源是( )。A.黄嘌呤氧化 B.乙酰CoA缩合 C
最新回复
(
0
)