题型:阅读理解 题类:常考题 难易度:普通
湖北省宜昌市协作体2018-2019学年高二上学期英语期末考试试卷(含小段音频)
The bristlecone pine (狐尾松) is one of the longest-living things on Earth. These trees, with their strangely shaped branches, can live up to 5,000 years, but experts worry that a warming climate in some areas may threaten its future.
Researchers say warmer weather is permitting a similar kind of tree, the limber pine (柔枝松), to take over good growing places from the ancient bristlecone. They say the tree is being forced out of mountainous areas where it grows.
Scientists at the University of California, Davis, say climate change is causing the trees to compete with each other.
Brian Smithers led the research project. “The limber pine is taking all the good spots,” he said.
Bristlecone pines grow in high mountain forests in eastern California, Nevada and Utah. In the mountains, they face high winds and extreme temperatures.
The difficult conditions leave the trees with twisted(变形的) branches and shapes. To survive long periods without water, parts of the trees die, including much of their outer bark (外皮). This makes the trees appear dead, except for small green pine needles. They show that the tree is indeed alive.
The oldest living bristlecone pine is somewhere in California. It is not marked in any special way, so that people do not try to damage it.
The limber pine is the bristlecone's distant relative and competitor, which can also live a long time — up to 2,000 years. Researchers say it is found at lower elevations (纬度), where temperatures are warmer.
The scientists at the University of California, Davis, recently released the results of a three-year study. Their research centered on trees that have started growing in the last 50 years in the Great Basin area of California's White Mountains. The researchers found that most of the trees growing at higher elevations were limber pines.
Smithers said, “It's very strange to see it charging higher up and not see the bristlecone charging up the mountain slopes ahead of the limber pine.”
Smithers said the bristlecones are not in danger of disappearing, but he thinks they could be forced out of some places where they have grown for thousands of years.
a. One of its living conditions is cold climate. b. The shape of the tree is twisted.
c. It has the longest life in the world. d. It can only be found in California.
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