A map of tree distribution around the world. Photo by Crowther, et al/Yale

NEW HAVEN, Conn., Sept. 2 (UPI) -- The latest forest census puts Earth's population of trees at 3 trillion strong. The total is up to 7.5 times more trees than some previous estimates.

The extra trees are nice surprise, but the good news is dwarfed by the reality of deforestation. As the new Yale-led study points out, the planet's population of trees has been nearly halved since humans showed up.


The new study used a combination of satellite imagery, forest inventories and powerful computer models to count Earth's trees. The results were published this week in the journal Nature.

Researchers say more accurate data about tree populations and forest distribution can improve the models used to understand large-scale global systems.

"Trees are among the most prominent and critical organisms on Earth, yet we are only recently beginning to comprehend their global extent and distribution," lead study author Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies, said in a press release.

"They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services," Crowther added. "Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don't know where to begin. I don't know what I would have guessed, but I was certainly surprised to find that we were talking about trillions."

The new tree data is expected to inform research into carbon storage models, forest ecosystems, biodiversity and more.

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The new study "moves us towards a needed direct quantification of tree distributions, information ready to be used by a host of downstream science investigations," said Matthew Hansen, a professor of geographical sciences at the University of Maryland who did not participate in the research.

While the new research may improve our understanding of the interplay between vegetation and climate change, it proves the planet's forests are already undergoing dramatic change.

Humans are the largest driver of deforestation, researchers say, and their new data further confirms the negative correlation between human and tree populations. Each year, Earth loses another 15 billion trees.