Humans Have Halved the Number of Trees on Earth

Without humans, our concrete jungles would be green.

There are approximately 3 trillion trees on Earth — seven and a half times the number previously estimated — a new study says. But that figure has fallen roughly 48 percent since the beginning of human civilization, according to scientists from Yale University's School of Forestry and Environmental Studies.

And it's falling — fast, thanks to human intervention. Humans are the top driver of tree numbers worldwide, the study found, after using satellite imagery, forest inventory information of more than 400,000 plots and “supercomputer technology” to map the world's trees. The research team recorded tree populations worldwide down to the square kilometer level to come up with their final figure, one that “certainly surprised” first author Thomas Crowther, Ph.D., a post-doctoral researcher at the school

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