The map, an explanation of the how the map was produced and a discussion of the maps can be found HERE. It is noteworthy to see how little of the earth is actually forested. Living amongst the big forest of the Pacific Northwest, it is easy to forget that much of the terrestrial landscape of our planet is not tree covered. Furthermore, a careful look at the map shows that the forest of Washington State is part of a forest with canopy height that is dark green on the map. The western North American temperate forests contain some of the biggest trees in the world and covers a large area with very tall trees. Our forests soak up a lot of carbon from the atmosphere.
The United States map shows that the United States has a lot of forest coverage. The eastern forests cover a larger area than the forest in the west, but the trees in the eastern forests do not attain the same heights as our western forests and the area covered by forest in the east has been diminished by agriculture and urban development. The forest pattern in the west is primarily defined by precipitation with the white areas consisting primarily of deserts or scrub steppe.