According to a new study, the answer is somewhere around 3.04 trillion.
That's about 400 trees for every person.
12,000 years ago, before the advent of agriculture, Earth had twice as many trees as it does now. Currently, our planet is losing 10 million trees a year.
"We used ground-sourced information," says Crowther. "All of the information that went into our models was generated from people standing on the ground counting numbers of trees in a given area. And so we could relate this information to what the satellites are telling us."
Previous estimates of the Earth's tree population put the number at 400.25 billion. That’s nearly an order of magnitude less than the new tally. Scientists say the discrepancy has to do with how the two estimates were calculated.
“Satellite images can tell you a lot about the forest area and canopy cover,” Crowther said. “What we provide is a more detailed understanding of what is going on beneath the surface.”
The new study incorporates satellite imagery, but it also relies on 429,775 ground-based measurements of tree density made by an actual person who counted the number of trees in a given area.
"We all gathered in a room, it was a very exciting time," remembers Crowther. "We'd been working toward it for two years."
The result: A staggering three trillion trees.
Researchers represented the number of trees across the globe using bars that are taller for denser forests.
Crowther added that one of the most dominant themes of the study is how large an effect humans are having on the tree population on the planet.
“Human activity came out as the strongest control on tree density across all biomes,” he said. “It really highlights how big of an impact humans are having on the Earth on a global scale.”
That's about 400 trees for every person.
12,000 years ago, before the advent of agriculture, Earth had twice as many trees as it does now. Currently, our planet is losing 10 million trees a year.
"We used ground-sourced information," says Crowther. "All of the information that went into our models was generated from people standing on the ground counting numbers of trees in a given area. And so we could relate this information to what the satellites are telling us."
Previous estimates of the Earth's tree population put the number at 400.25 billion. That’s nearly an order of magnitude less than the new tally. Scientists say the discrepancy has to do with how the two estimates were calculated.
“Satellite images can tell you a lot about the forest area and canopy cover,” Crowther said. “What we provide is a more detailed understanding of what is going on beneath the surface.”
The new study incorporates satellite imagery, but it also relies on 429,775 ground-based measurements of tree density made by an actual person who counted the number of trees in a given area.
"We all gathered in a room, it was a very exciting time," remembers Crowther. "We'd been working toward it for two years."
The result: A staggering three trillion trees.
Researchers represented the number of trees across the globe using bars that are taller for denser forests.
Crowther added that one of the most dominant themes of the study is how large an effect humans are having on the tree population on the planet.
“Human activity came out as the strongest control on tree density across all biomes,” he said. “It really highlights how big of an impact humans are having on the Earth on a global scale.”
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