There is good and bad news about the number of trees on our planet. The good news is that there are seven times more trees than we thought. A few years ago, scientists believed that the world had 400 billion trees. However, a new study from Yale University shows that there are around three trillion (万亿) trees. That's a three followed by 12 zeroes. That means there are about 420 trees for everyone in the world today.
The bad news is that thousands of years ago, the earth had six trillion trees. Humans cut down half the number of trees on the planet. Take Europe for example, it was a large forest thousands of years ago. Now much of it is cities and towns. And another 15 billion trees are lost each year.
Dr Thomas Crowther is one of the scientists from Yale University. He said the new number of trees from their study would change nothing. "The study only shows we need to do more to protect our forests," he said.
