Earth Home To 3 Trillion Trees, Half As Many As When Human Civilization Arose

sciencehabit writes: Earth today supports more than 3 trillion trees—eight times as many as we thought a decade ago. But that number is rapidly shrinking, according to a global tree survey released today (abstract). We are losing 15 billion trees a year to toilet paper, timber, farmland expansion, and other human needs. So even though the total count is large, the decline is "a cause for concern," says Tom Spies, a forest ecologist with the U.S. Forest Service in Corvallis, Oregon, who was not involved with the work.