A new international study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. This number was formulated by collecting tree density information from more than 400,000 forest plots around the world. But the total number of trees has plummeted by roughly 46 percent since the start of human civilization. The results provide the most comprehensive assessment of tree populations ever produced and offer new insights into a class of organism that helps shape most terrestrial biomes.
Source: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14967.html
