Missouri was once a mosaic of prairies, savannas, woodlands, and forests. Today the region is characterized by forests or agricultural land; many of the natural communities that supported a diversity of plants and animals are lost. Restoration of natural communities is a primary management goal for the Mark Twain National Forest, other federal and state land agencies, and conservation organizations. To guide restoration, a better understanding is needed of the historic communities and landscape conditions and how they have changed. Forest Service scientists at the agency’s Northern Research Station studied General Land Office surveys, circa 1815 to 1850, to characterize the historic vegetation and compared their findings with modern conditions, 2004 to 2008, from Forest Inventory and Analysis data. They found that oak species are less dominant and species such as hickories, eastern redcedar, elms, and maples have become more prominent. Trees are smaller in diameter and occur in dense forests; savanna and woodland communities are gone. The Ozarks are largely a mature forest landscape that is less diverse and more homogeneous; and, in western and northern Missouri, prairies have been converted to agriculture. These changes have serious implications to ecosystem health, productivity, and resilience to future stresses from changing climate and invasive species.