From NASA’s Earth Observatory:
“The coastal Pacific Northwest of the United States has the tallest trees in North America, averaging as much as 40 meters (131 feet) in height. It has the densest biomass—the total mass of organisms living within a given area—in the country. But for centuries, it also has been a much-tapped resource for lumber; land-clearing for agriculture and development have also trimmed the woodlands. Both the lumber companies and forest managers have an interest in measuring the health of these forests.
The maps above are a subset of that nationwide mapping project. The top map shows one of 66 mapping zones across the country; in this case, Washington state and a sliver of Oregon. The inset map (lower) shows the fine scale of that forest (the image is roughly 20 kilometers wide), which allows researchers to see the regular patterns of logging and development, and the more erratic shape of areas lost to fires and pests.”