How scientists counted every tree on Earth—and the startling results
From Nature Video: It’s a simple question: how many trees are there on Earth? The answer required 421,529 measurements from fifty countries on six continents. Their findings? The earth is losing 10 billion trees every year. Now this data has been combined to produce a stunning visualisation of earth as you’ve never seen it before.
The Earth Is Losing 10 Billion Trees Every Year
According to a new study, there are more than 3 trillion living trees on earth, and the fascinating, Nature-produced animation above shows where—and how tall—they really are.
This research, led by Thomas Crowther of Yale, was recently published in Nature. For the study, people were actually sent out to count trees; previous estimates were based solely on satellite imagery. Researchers used the hand counts to show that there are far more trees than we thought.
That’s the good news. The bad news: We’re losing about 10 billion trees a year. And that before humans showed up on the scene, there were twice as many trees. Watch more in the video above.
RESEARCH PAPER ABSTRACT
Mapping tree density at a global scale
The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.30 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.66 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.