Five Million Trees
It took researchers six years to put together this U.S. national forest map using information gathered from space-based radar, satellite sensors, computer models, and huge amounts of ground-based data. The team calls it "possibly the highest resolution and most detailed view of forest structure and carbon storage ever assembled for any country." Woods Hole investigator Josef Kellndorfer estimates that the database includes measurements of about five million trees; darker greens show areas with denser forest biomass. Here's a larger version of the map.
Map by Robert Simmon, based on data from Woods Hole Research Center.