听力文本

By June the days are at their longest,
6月是白昼最长的时候，
and all across the northern hemisphere the broad leaves are hard at work.
所有北半球的阔叶树木努力生长。
On the east coast of North America it seems like any other summer's evening, but tonight is special.
在北美洲的东部，这里的夏日傍晚和其他地方一样，不过今晚非常特别。
After seventeen years underground, creatures are stirring.
在17年的地下潜伏后，生物开始活跃起来。
The nymphs of the periodical cicada have been biding their time.
布鲁德X蝉（一种周期蝉）的若虫为这个机会等待了很长时间。
Now they march like zombies towards the nearest tree, and start to climb.
现在它们如朝圣般向最近的树进军，并开始攀爬。

At first, there are merely thousands, but soon, more than a billion swarm all over the forest.
一开始不过几千只，马上10亿只若虫爬满了整个森林。
The biggest insect emergence on the planet is underway.
地球上最大规模的昆虫羽化就要开始了。
They invade the upper branches, where they climb out of their external skeletons and assume their adult winged form.
占据上端的树枝后，若虫开始进行转变到蝉的蜕皮动作。
At first they're white and soft, but they have until dawn to complete their transformation.
一开始它们又白又软，直到黎明它们才完全转化完毕。

视频及简介

在北极边缘有着大片针叶树林，那是矮小的针叶科树木寂静的世界。那些树或许真的很矮，但在高空拍摄下，树林显示出其真实的大小。世界有1/3的树木都生长在这里，在短暂的夏季里，这些树木制造了大量的氧气足以改变的大气的成份。