As much as 1/3 of the total tree cover has been lost since agriculture began some 10,000 years ago.
The remaining forests are home to half of the world's species, thus becoming the chief resource for their survival.
Tropical rain forests once covered 12% of the land of the planet, as well as supporting at least half of the world's species of plants and animals.
These rain forests are home to millions of people.
But there are other demands on them.
For example, much has been cut for timber.
An increasing amount of forest land has been used for industrial purposes or for agricultural development such as crop-growing.
By the 1990s, less than half of the earth's original rain forests remained, and they continued to disappear at an alarming rate every year.
As a result, the world's forests are now facing gradual extinction.
世界的森林正在消失。
自從農(nóng)業(yè)在大約10000年以前開始之日起,整個森林已經(jīng)銳減了三分之一。
剩下的森林是地球上半數(shù)物種的家園。
森林是他們生存的主要資源。
熱帶雨林曾經(jīng)覆蓋了地球12%的陸地,同時供養(yǎng)了至少半數(shù)的動植物。
這些雨林是數(shù)以百萬人類的家園。
但是人們對它們有些其他的需求。
例如。
它們的大多數(shù)被砍作木材。
被工業(yè)和農(nóng)業(yè)征用的數(shù)量與日俱增。
截止90年代,現(xiàn)存的雨林還不足半數(shù),并且它們繼續(xù)以驚人的速度在消失。
導(dǎo)致世界的森林正面臨逐漸消失的境地。
瘋狂英語 英語語法 新概念英語 走遍美國 四級聽力 英語音標(biāo) 英語入門 發(fā)音 美語 四級 新東方 七年級 賴世雄 zero是什么意思肇慶市富堅廣場英語學(xué)習(xí)交流群