The vegetation of Tennessee is classified into five major systems: upland, palustrine, riverine, lacustrine, and anthropogenic. Upland systems represent the "natural" communities that range from mesic to xeric in moisture and includes most types of forests, woodlands, grasslands, glades, and cliff communities. Palustrine systems represent the many types of herbaceous and forested wetlands, and it also includes riparian communities. The limits of the palustrine system follows the Cowardin et al. (1979) classification. The Riverine system includes rivers, streams, and springs and the limits of the riverine system follows the definition of Cowardin et al. (1979). Lacustrine systems, represented by natural lakes, are recognized following the definition of Cowardin et al. (1979). Note that man-made lakes (impoundments and reservoirs) are classified in the Anthropogenic System. Lastly, the anthropogenic system attempts to classify the myriad human-altered or man-made communities. Examples include man-made reservoirs, pine plantations, agricultural fields, pastures, and the various communities that are the result of 300+ years of impacts to the Tennessee landscape since colonization by Europeans.