Figure 1.

The forest regions were defined as combinations of CEC (Commission for Environmental Cooperation, 1997) Level I ecoregions of North America: The North (green) included the Taiga and Northern Forests; the East (red) included the Eastern Temperate Forests and Tropical Humid Forests; the West (blue) included the Marine West Coast Forests, Northwestern Forested Mountains, and Temperate Sierras; and the nonforest region (white) included all other ecoregion classifications.