We may sing about purple mountains and amber grains, but one of world's most vital resources is its vast amount of carbon-catching, oxygen-spewing trees. Now, after six years of effort, NASA knows how many the US has, at least.
Josef Kellndorfer and Wayne Walker of NASA's Woods Hole Research centre worked in conjunction with the National Geological Survey and US Forest Service to catalogue a mix of data gleaned from space-based radar, satellite sensors, computer models and old-fashioned tree counting. The map above shows the total amount of woody biomass in the USA.
It's displayed at a 30m resolution, where every four pixels constitutes an acre and every 10 represents a hectare. In total, Kellendorfer estimates some five million trees reside on US soil. [NASA Earth Observatory via Business Insider via Geekosystem]