List of Ecoregions defined as mostly Forestland

5.2.1 Northern Lakes and Forests 8.1.8 Acadian Plains and Hills
5.3.1 Northern Appalachian and Atlantic Maritime Highlands 8.3.4 Piedmont
5.3.3 North Central Appalachians 8.4.3 Western Allegheny Plateau
8.1.3 Northern Allegheny Plateau 8.4.5 Ozark Highlands

For more information regarding U.S. Ecoregions Level III, please follow this link.