Forests in the U.S. were mapped down to a scale of 30 meters, or roughly 10 computer display pixels for every hectare of land (4 pixels per acre). They divided the country into 66 mapping zones and ended up mapping 265 million segments of the American land surface. Kellndorfer estimates that their mapping database includes measurements of about five million trees.
Chris Howard: "What I really wanted was this blended map with a population density overlay. Because what really stands out is how red the nation seems to be when you do not take the voting population into account; when you do so many of those vast red mid-west blocks fade into pale pink and lavender (very low population)."