Trees are more than beautiful: They’re vital for animals and the environment. But just how many trees are there on Earth, anyway? Up until now, nobody really knew for sure. But now, Discovery.com reports on a new census that shows that Earth is host to a staggering 3.02 trillion trees — more than scientists expected.
Researchers didn’t go from tree to tree for their census (if they tried it that way, they’d certainly die before they even made a dent in the task.) Rather, reports Discovery.com, they relied on previous studies, satellite imagery, and information on how dense some forests are. In a release, the international team called its results “the most comprehensive assessment of tree populations ever produced.”
Previous reports of the world’s tree counts seem to have been pretty conservative: The most recent estimate only counted 400 billion trees, reports Nature.com’s Rachel Ehrenberg. Because prior studies used satellite technology alone instead of including data from on-the-ground tree density studies, writes Ehrenberg, they missed the mark.
The study shows that there are about 422 trees per person, but where are all those trees located? If you guessed the tropics, you’re right: 43 percent of the world’s trees grow in such areas, while the densest areas of tree growth can be found in sub-arctic regions in places like Russia, Scandinavia and North America.
But there’s a dark side to the report: evidence that human beings have cut the number of trees on the planet nearly in half. In their paper, the team notes that human activity destroys 15.3 billion trees per year. They also estimate that since human civilization began, 45.8 percent of all trees been lost. In fact, researchers note that the effect of humans on trees was the only consistent one across all tree habitats, beating out factors like moisture and temperature.