福克斯新闻 地球上有3万亿棵树 比史前减少数万亿棵（在线收听）

There are now more than 3 trillion trees growing on Earth, which is seven times more than scientists previously thought.

That said, there are also trillions fewer than there used to be.

The leafy findings are from a study published Wednesday in the journal Nature by Yale forestry researcher Thomas Crowther.

Crowther and his colleagues used 429,775 ground based measurements with satellite measurements and computer models for the count.

But with people cutting down 15 billion trees a year, and only 5 billion replanted, Crowther says Earth's trees could be gone in about 300 years.

地球上目前生长着超过3万亿棵树木，是科学家们此前所认为的树木数量的7倍。

也就是说，这也比曾经的树木数量少了数万亿棵。

美国耶鲁大学的林业研究人员托马斯·克劳瑟在英国《自然》周刊发表的一项研究报告中得出了这样的结论。

克劳瑟和他的同事们利用陆基测量，卫星测量及计算机模型模拟演算得到了更为精确的数字，429,775。

但随着每年人们砍伐150亿棵树,只有50亿棵树重新种植, 克劳瑟表示地球上的树木可能在300年内消失。