长期干旱影响加州的红杉
时间:2019-01-12 作者:英语课 分类:2015年VOA慢速英语(十)月
AS IT IS 2015-10-04 Drought Affecting California’s Sequoias 长期干旱影响加州的红杉
California continues to suffer under a historic drought. The state has received very little rainfallover the past four years.
California is famous for its huge sequoia 1 trees. They are among the largest and oldest living thingson Earth. But scientists say the trees are suffering because of the lack of water.
Now the National Park Service is studying how the drought has affected 2 the sequoias and what canbe done to help them survive.
Anthony Ambrose is a tree biologist with the University of California, Berkeley. One recent day, heslowly climbed up a giant sequoia in California's Sierra Nevada Mountains. The Sierra Nevada rangeis the only place on earth where sequoias live.
"It's an amazing experience to be able to climb up into these things and know that it's beengrowing in this same spot for you know a thousand years or more."
Sequoias can grow to a height of over 90 meters tall. The bottom of the tree can be up to 15meters wide. Some trees are more than 3,000 years old.
The Sierra Nevada range once had plenty of water because of mountain streams. But less water isavailable now because of the drought. Each sequoia needs more than 3,000 liters of water a day. The trees are now getting much less. Some of them are showing signs of thirst, says AnthonyAmbrose.
"We've observed some unusual and abnormal levels of foliage 3 die-back, which haven't beenobserved in the park before."
Researchers are using scientific equipment in tree canopies 4 to help measure air temperature andhumidity levels. They also are studying sequoia seedlings 5, information from individual trees andimages collected by aircraft to measure the seriousness of the danger.
One possible solution would be to cut down less important tree species because other plantscompete with the sequoias for water. Koren Nydick of the National Park Service is one of thescientific investigators 6.
"They'll have more water than they would have in a denser 7 forest, more nutrients 8 and light andtherefore be more resistant 9 and resilient to these hot droughts they're faced with in the future."
Scientists say that over thousands of years, sequoias have survived many droughts, forest fires,insect infestations 10 and other disasters. Scientists say the sequoias will probably survive thisdrought, unlike many other California trees.
Words in This Story
drought – n. a long time during which there is very little or no rain
thirst – n. a very great need for something to drink
die-back - n. a condition in which a plat begins, owing to disease or an unfavorable environment
canopy 11 - n. something that hangs or spreads out over an area
humidity – n. wetness in the air
- The sequoia national forest is at the southern end of the sierra nevada range.红杉国家公园位于内华达山脉南端尽头处。
- The photo shows the enormous general Sherman tree in California's sequoia national park.照片显示的是加利福尼亚州红杉国家公园内巨大的谢尔曼将军树。
- She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
- His manners are affected.他的态度不自然。
- The path was completely covered by the dense foliage.小路被树叶厚厚地盖了一层。
- Dark foliage clothes the hills.浓密的树叶覆盖着群山。
- Golf carts with bright canvas canopies wandered the raingreen fairways. 一场雨后显得愈加葱绿的高尔夫球场草地上,散放着一些带有色彩缤纷的帆布华盖的高尔夫小车。
- Rock permitted seven canopies, cornices floors, decorative glass, Ambilight, momentum magnificent, magnificent. 七檐佛殿背倚山岩,楼层飞檐翘角,殿顶琉璃装饰,流光溢彩,气势恢宏,蔚为壮观。
- Ninety-five per cent of the new seedlings have survived. 新栽的树苗95%都已成活。 来自《现代汉英综合大词典》
- In such wet weather we must prevent the seedlings from rotting. 这样的阴雨天要防止烂秧。 来自《现代汉英综合大词典》
- This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
- The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》
- The denser population necessitates closer consolidation both for internal and external action. 住得日益稠密的居民,对内和对外都不得不更紧密地团结起来。 来自英汉非文学 - 家庭、私有制和国家的起源
- As Tito entered the neighbourhood of San Martino, he found the throng rather denser. 蒂托走近圣马丁教堂附近一带时,发现人群相当密集。
- a lack of essential nutrients 基本营养的缺乏
- Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》
- Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
- They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
- The arrival of warm weather raises the specter of disease and increased rat infestations caused by rotting garbage. 天气转暖使人们担心垃圾腐烂会引起疾病传播和鼠群猖獗。 来自《简明英汉词典》
- Piperazine citrate is the drug of choice in the treatment of Ascaris infestations. 枸橼酸哌嗪治疗蛔虫感染是最好的药物。 来自辞典例句