World has many more trees than previously thought
By Mark Armao, Wall Street Journal
There are slightly more than three trillion trees in the world, a figure that dwarfs previous estimates, according to the most comprehensive census yet of global forestation.
Using satellite imagery as well as ground-based measurements from around the world, a team led by researchers at Yale University created the first globally comprehensive map of tree density. Their findings were published in the journal Nature on Wednesday.
A previous study that drew on satellite imagery estimated that the total number of trees was about 400 billion. The new estimate of 3.04 trillion is multiple times that number, bringing the ratio of trees per person to 422 to 1.