Earth's Three Trillion Tree Population Means 422 Trees Per Person

Three trillion trees populate the Earth, a new study revealed this week, sharply upgrading previous estimates of just 400 billion trees on the planet.

The more accurate estimate of the number of trees on the planet was published in the journal Nature this week and was based on scientific data gathered from all continents except Antarctica. The previous smaller estimate was based on satellite imagery, but Netherlands ecologist Thomas Crowther, who led the study, said the new data has a more accurate reading for tree density.

"It’s not like we discovered new trees,” Crowther told Nature. “Rather, we added another layer of information that allowed us to revise much of the previous estimates.”

Along with increasing the estimated number of trees on Earth by seven times, the researchers also reported in Nature that humans cut down about 15 billion trees every year and that, since civilization began, humans have destroyed about half the trees in the world.

“The scale of human impact is astonishing,” Crowther said. “Obviously we expected humans would have a prominent role, but I didn’t expect that it would come out as the as the strongest control on tree density.”

Although the good news is that there are now about 422 trees per person, deforestation continues to change those numbers, The Washington Post reported.

"It does not say there’s more forest. It just says there’s more trees in the forest," Thomas Lovejoy, a conservation biologist at the United Nations Foundation, told the newspaper. But Lovejoy, who was not involved in the published research, lauded the study for the information gathered and said the use of big data and fieldwork is important.

Crowther told The Post that he was inspired by the Billion Tree Campaign to launch this research initiative.

"They want to generate forests on a global scale," he said. "But they had absolutely no baseline information about how many trees they needed to plant to do that."

The Billion Tree Campaign was a 2006 United Nations project designed to encourage people to plant trees worldwide. It recently announced that the campaign has been handed over to the Plant for the Planet Foundation.

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