Earth is Home to Over 3 Trillion Trees

Posted on September 3, 2015

Global Map of Tree Density

There are over 3 trillion trees on Earth according to a new study led by Yale researchers. This is 7.5 times as many trees as estimated by previous studies. The study also found that the total number of trees has fallen by about 46% since the start of human civilization.

The study involved a combination of satellite imagery, forest inventories and computer algorithms. It involved 421,529 measurements from fifty countries on six continents. The study was inspired by a request by Plant for the Planet, a global youth initiative, that called for baseline estimates of tree numbers at regional and global scales.

Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies (F&ES) and lead author of the study, says in a statement, "Trees are among the most prominent and critical organisms on Earth, yet we are only recently beginning to comprehend their global extent and distribution. They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services. 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 study also determined that there are about 422 trees per person on Earth. The tropics contain a 42% of the world's trees. 24% of the world's trees are found in dense boreal regisions and 22% exist in temperate zones. The researchers say that 15 billion trees are lost each year due to human activities including deforestation, land-use change and forest management.

The tree report was published in the journal, Nature.



Image: Crowther, et al