There are just over three trillion trees in the world—well above previous estimates of around 400 billion—according to findings published yesterday in Nature.
The study was led by researchers at Yale University and is the most comprehensive enumeration of the planet’s forestation in history.
The tree density map was created using satellite imagery on climate, topography, and land use, as well as 429,775 ground-based measurements around the world. Together, the data helped researchers create models for predicting tree density. For any areas in which there were no field measurements, the team made estimates using information from areas with similar features.
The 3.04 trillion total trees on Earth mean there are 422 trees for every person, and while that figure is larger than expected, the global population of trees is still in decline. The reports figure that vegetation has fallen by 45.8 percent since the arrival of humans, and continues to decrease by about 10 billion trees every year. About 15.3 billion trees are cut down annually, with regrowth and reforestation making up for some of that loss.
“We can now say that there’s less trees than at any point in human civilization,” lead author Thomas Crowther told The Washington Post. “Since the spread of human influence, we’ve reduced the number almost by half, which is an astronomical thing.”
The detailed look at the arbor population will be a useful guideline for future studies related to climate change, both in understanding how the trees affect shifts in climate, and in how environmental changes impact them.