There are approximately 3.04 trillion trees in the world. That’s a huge number that looks even more impressive when it’s written out: 3,040,000,000,000.
But what’s more astonishing is that we didn’t have this estimate until recently. In fact, scientists used to believe that the number of worldwide trees was a whole lot lower. No one bothered to do the dirty work of tree counting until recently.
That current estimate is based on the work by Thomas Crowther, a professor at the Yale School of Forestry and Environmental Studies. He had a friend who launched an ambitious project to plant a billion trees in order to fight global warming. But there was was just one major problem: they had no idea whether or not a billion trees is a lot of trees.
"They didn't know if planting a billion trees was going to add 1% of the world's trees, or add 50% of the world's trees," Crowther says. "They didn't even know if it was even possible to fit a billion trees on Earth."
One estimate, based on satellite data, pegged the number of trees worldwide at 400 billion. The problem? A survey of the Amazon Basin revealed that there were are roughly that number of trees in that area alone.
So, over the course of two years, Crowther appointed himself the world’s foremost tree counter. He gathered data from 400,000 forest plots that had been gathered from the world’s forestry services. After a lot of computer-assisted number crunching, they finally arrived at a more precise estimate: 3.04 trillion. Crowther was even able to calculate the number of trees by region. 1.30 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.66 trillion in temperate regions. Those numbers were published in his Nature paper about the study, entitled “Mapping Tree Density at a Global Scale.”
While three trillion trees sounds like an astronomical number, it’s almost half as much as what used to exist. According to Crowther’s paper, the global number of trees has fallen approximately 46% since the beginning of human civilization.
And how did this affect the group that aimed to plant a billion trees? That number, after all, is a mere .03 percent of the total number of trees worldwide. It forced the organization, Plant for the Planet, to set their sights a little higher. They now have the aim of planting a trillion trees worldwide.