A new Yale study estimates that Earth is home to a staggering 3.04 trillion trees, a number 7.5 times larger than previous estimates.
The study, published in the journal Nature, combined satellite imagery, forest inventories and supercomputer technologies to get an accurate count of tree populations worldwide. Previous research relied exclusively on satellite data, which is why the previous estimate of tree population, 400 billion, was erroneous.
“It’s not like we discovered new trees,” says Thomas Crowther, an ecologist now at the Netherlands Institute of Ecology in Wageningen who led the study while at Yale University in New Haven, Connecticut. “Rather, we added another layer of information that allowed us to revise much of the previous estimates.”
While this is good news for nature-lovers, the study also found that the total number of trees has plummeted by roughly 46 percent since the start of human civilization 12,000 years ago.
“The scale of human impact is astonishing,” says Crowther. “Obviously we expected humans would have a prominent role, but I didn’t expect that it would come out as the strongest control on tree density,” he told Nature.