VOA常速英语2015--干旱对加州红杉造成影响（在线收听）

干旱对加州红杉造成影响

Slowly and painstakingly, University of California tree biologist Anthony Ambrose climbs up a giant sequoia in California’s Sierra Nevada mountain range, the only place on earth where these magnificent trees live.

加利福尼亚大学植被生物学家安东尼·安波罗修攀登前往了加州内华达山脉的红杉区，壮丽的北美红杉仅分布于这片区域。

It’s an amazing experience to be able to climb up into these things and know that it's been growing in this same spot for a thousand years or more。

能够攀登高峰，看到它们真的是一次不错的体验，北美红杉已经在这里生活了一千多年。

Sequoias grow over 90 meters tall, their trunks are up to 15 meters wide and some of them are more than 3,000 years old.

红杉的高度超过了90米，树干能够达到15米宽，许多红杉的树龄已经超过了3000年。

Once-rich mountain streams have dwindled to trickles and the trees that each need more than 3,000 liters of water a day are now getting much less. Some of them are showing signs of thirst.

曾经汹涌的山涧已经变成了小溪，对于每天需要喝下3000公升水的红杉来说，它们的饮用量正在减少。许多红杉已经显现出了干渴的迹象。

We've observed some unusual and abnormal levels of foliage die-back, which haven't been observed in the park before.

我们已经观察到了一些不正常的树枝枯梢现象，这在之前是没有遇见过的。

Sensors installed in tree canopies, examinations of seedlings, data from individual trees and images collected by observational planes will help scientists measure the seriousness of the danger.

人们在红杉的华盖上安装了传感器，并对幼苗进行检测，观测飞机将收集每棵红杉的数据和图像，而这些也将帮助科学家判定情况的严重性。

One possible solution would be to cut down less important species of trees that compete with sequoias for water.

一种可行的办法就是减少非重要树种的数量，增加红杉的需水量。

They'll have more water than they would have in a denser forest, more nutrients and light and therefore be more resistant and resilient to these hot droughts they're faced with in the future.

比起在茂密的森林，红杉需要更加充足的水资源、营养以及阳光、对于它们未来需要面对的干旱天气，它们需要更强的适应能力。

Scientists say that over thousands of years, sequoias have gone through many droughts, forest fires, insect infestations and other calamities, so they will probably survive this drought, unlike many less-resilient California trees.

科学家称数千年来，红杉经历了许多次的干旱、森林大火、虫害以及其他天灾，不像加州的其他植被，由于它们的适应性较弱，它们不会像红杉一样逃过此次干旱。