Apart from the Atlantic and Gulf coastal plain, this zone includes a large part of the eastern United States. In the north it extends into southern Canada to include southeastern Ontario and southern Quebec, while in the south it extends to central Georgia, central Alabama, parts of eastern Texas and includes much of Arkansas. Its western boundary extends to Minnesota, eastern Iowa, the Ozark Plateau and the Quachita Mountains.

Appalachian Forests

At higher elevations, above 1300m spruce-fir forests predominate including Picea rubens red spruce, and the endemic Abies balsam balsam fir and Abies fraseri fraser fir (Pinaceae).  At lower elevations between 250-1300 m mixed oak (Quercus spp.) forests predominate which once supported massive tulip trees Lirodendron tulipifera and endemic chestnut Castanea dentate (Fagaceae).  However, in the 1900s the spread of chestnut blight caused by the fungus Cryphonectria parasitica resulted in the widespread loss of chestnut. This allowed species such as Quercus prinus, Q. rubra, Q. velutina and the endemic locust tree Robinia pseudoacacia (Fabaceae) to profliferate. Other endemic trees of semi-upland areas include the two endemic lime trees Tilia americana and T. heterophylla (Tiliaceae).  In the rolling hills west of the Appalachian Mountains are relicts of ancient mesic forests that once covered much of the temperate regions of North America. These support a variety of forest types with magnolias such as the endemic Magnolia acuminata and M. fraseri (Magnoliaceae), endemic oaks (Quercus), endemic hickories (Carya), walnuts including the endemic Juglans cinerea (Juglandaceae), elms including the endemic Ulmus serotina and U. thomasii (Ulmaceae), locusts including the endemic Robinia hispida (Fabaceae), maples including the endemic Acer nigrum, A. pensylvanicum, and A. saccharum (Aceraceae) together with the endemic conifer Tsuga canadensis (Pinaceae) Eastern Hemlock. Understory species include various endemic rhododendron, the endemic Prunus alleghaniensis (Rosaceae) and the rich ground layer comprising various endemic vernal species such as Allium tricoccum (Alliaceae), Caulophyllum thalictroides (Berberidaceae), Claytonia virginica (Portulacaceae), Dicentra canadensis, D. cucullaria (Fumariaceae), and Laportea Canadensis (Urticaceae), while the more shade tolerant endemics include Asarum canadense (Aristolochiaceae) and Fragaria virginiana (Rosaceae).

Appalachian Ozark Mountain Forests

These forests situated mainly on the Quachita and Boston Mountain comprises some of the best-developed oak-hickory forest in the United States. The primary species are Quercus rubra, Q. alba, various Carys species especially Carya texcana. Associated endemic taxa include Tilia Americana (Tiliaceae).

References

Cain, S. A. 1943. The Tertiary character of the Cove hardwood forests of the Great Smoky Mountains National Park. Bulletin of the Torrey Botanical Club, 70: 213-235.

Cooper, A. W. 1979. The natural vegetation of North Carolina. In: Contributions to the knowledge of flora and vegetation in the Carolinas. Eds. H. Leith and E. Landolt. VGI Zurich.

Estill, J. C. & Cruzan, M. B. 2001. Phytogeography of rare plant species endemic to the southeastern United States. Castanea, 66: 3-23.

Greller, A. M. 1989. Deciduous Forest.  In: North American Terrestrial Vegetation. Eds. M. G. Barbour & W. D. Billings. Cambridge University Press.

Pittillo, J. D. & Smathers, G. A. 1979. Phytogeography of the Balsam Mountains and Pisgah Ridge, Southern Appalachian Mountains. In: Contributions to the knowledge of flora and vegetation in the Carolinas. Eds. H. Leith and E. Landolt. VGI Zurich.

Qian, H. 1999. Floristic analysis of vascular plant genera of North America north of Mexico: characterization and phytogeography.  Journal of Biogeography, 26: 1307-1321.

Ricketts, T. h. et al. 1999. Terrestrial Ecosystems of North America - a conservation assessment. World Wildlife Fund, USA and Canada. Island Press, Washington.