File:Mapping Tree Density 1.png: Difference between revisions

(Earth Science News via Slate, Dec 2016)

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.

Data Sets

http://elischolar.library.yale.edu/yale_fes_data/1/

https://www.natureindex.com/article/10.1038/nature14967

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 1.39 trillion exist in tropical and subtropical regions, with 0.74, and 0.61 trillion in boreal and temperate regions, respectively. 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 impact of humans across most of the world. Based on our projected tree densities, we estimate that deforestation is currently responsible for removing over 15 billion trees each year, and the global number of trees has fallen by approximately 46% since the start of human civilisation.