Yale Researchers Count All Trees on Earth: 3.04 Trillion and Dropping

Did you think that it was impossible to count all the trees on Earth? Using a combination of old-fashioned headcounts, high-tech satellite imaging and some impressive supercomputers, experts have reached a final number: 3 trillion trees – roughly 8 times more than previous estimations led us to believe.

The Yale University team admitted to have been really surprised by the new figure, but they claim it’s the most accurate tree census that has ever been conducted.

Senior author Thomas Crowther of the Yale School of Forestry and Environmental Studies, Connecticut, said the team didn’t really know what to expect, but finding out they were talking about trillions of trees brought the spirits up.

Reporting for the journal Nature, researchers also had some bad news to deliver. Even though there are currently 422 trees for each person on this planet, estimations revealed that trees have almost halved since human civilization started leaving its print on them.

What’s even more distressing is that deforestation is still taking place at unabated pace; according to the study, each year around 15 billion trees are felled. The research is based on certified tree counts covering 400,000 forests.

Then, following the data offered by satellite imagery, researchers included factors like topography, climate, soil conditions, vegetation, and human impact in order to see which affected tree density the most.

Tree numbers could then be estimated by developing models for regional levels, which then offered the greater picture of a global map of Earth’s forests: roughly 3.04 trillion trees.

Unsurprisingly, the regions with the fewest human populations were also the ones experiencing the highest densities of trees, including Russia’s boreal forests from its sub-arctic regions, North America and Scandinavia. But the tropics won by far at the category of “largest forest areas,” hosting about 43 percent of the total number of Earth’s trees.

Bad news is, human activity is by far the worst factor impacting tree numbers, guilty of land-use change and massive deforestation. Ever since humans started clearing the land and planting seeds, tree numbers have dropped with 46 percent.

Researchers concluded that, in other words, when human population increases, tree densities are usually the ones to suffer. Halving the number of trees on the planet is no little thing, and human impact has to be drastically reduced if we want forests worldwide to have a chance of surviving us.

Trees and forests are not only important because they offer us oxygen, shelter and fuel, but they also play a huge role in storing immense quantities of carbon; if there are no trees to trap it in, global warming wins.
Image Source: National Geographic

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Ryan has started his career as a web developer and designer before joining us. He enjoys the creativity work and loves experimenting with various techniques in both print and web. He covers the social media, technology and gadgets updates.