The Central U.S. hardwood forests comprise a Temperate broadleaf and mixed forests

Temperate broadleaf and mixed forests

Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...

 ecoregion

Ecoregion

An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

 in the Eastern United States

Eastern United States

The Eastern United States, the American East, or simply the East is traditionally defined as the states east of the Mississippi River. The first two tiers of states west of the Mississippi have traditionally been considered part of the West, but can be included in the East today; usually in...

. It has one of the most diverse herbaceous plant floras of ecoregions in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

.

Setting

This is a large region, mainly of rolling plain except for the Ozark plateau and other smaller areas of plateau and basin in Kentucky

Kentucky

The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

 and Tennessee

Tennessee

Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...

. The region contains the large system of sandstone caves in Mammoth Cave National Park

Mammoth Cave National Park

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established...

.
The region was designated by the World Wide Fund for Nature

World Wide Fund for Nature

The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...

 (WWF) and is a fraction of what others consider the Central Hardwood Forest of the Central Hardwood Region, which would include the northern hardwood forest

Northern hardwood forest

The northern hardwood forest is a general type of North American forest ecosystem found over much of southeastern and south central Canada, extending south into the United States in northern New England and New York, and west along the Great Lakes to Minnesota and western Ontario...

 to the north.

This is an inland area with a fairly dry climate.

Flora

The pre-Columbian

Pre-Columbian

The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences on the American continents, spanning the time of the original settlement in the Upper Paleolithic period to European colonization during...

 dominant ecosystems in this region were oak savanna

Oak savanna

An oak savanna is a type of savanna, or lightly forested grassland, where oaks are the dominant tree species. These savannas were maintained historically through wildfires set by lightning, grazing, low precipitation, poor soil, and/or fires set by Native Americans...

s with woodlands and forests of oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 and hickory

Hickory

Trees in the genus Carya are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts...

. Today only small areas of oak and hickory woodland remain, mixed with dogwood

Dogwood

The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...

s, sassafras

Sassafras

Sassafras is a genus of three extant and one extinct species of deciduous trees in the family Lauraceae, native to eastern North America and eastern Asia.-Overview:...

 trees and hop hornbeam

Ostrya

Ostrya is a genus of eight to ten small deciduous trees belonging to the birch family Betulaceae. Its common name is Hophornbeam in American English and Hop-hornbeam in British English. It may also be called ironwood, a name shared with a number of other plants.The genus is native in southern...

s. The ecoregion contains large areas of prairie

Prairie

Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...

 as well as wetter meadows that are home to tulip trees

Liriodendron tulipifera

Liriodendron tulipifera, commonly known as the tulip tree, American tulip tree, tuliptree, tulip poplar or yellow poplar, is the Western Hemisphere representative of the two-species genus Liriodendron, and the tallest eastern hardwood...

 and sweetgums.

Fauna

Birds of the woodlands include vireo

Vireo

The vireos are a group of small to medium-sized passerine birds restricted to the New World. They are typically dull-plumaged and greenish in color, the smaller species resembling wood warblers apart from their heavier bills...

s and tanager

Tanager

The tanagers comprise the bird family Thraupidae, in the order Passeriformes. The family has an American distribution.There were traditionally about 240 species of tanagers, but the taxonomic treatment of this family's members is currently in a state of flux...

s while mammals include Eastern gray squirrel

Eastern Gray Squirrel

The eastern gray squirrel is a tree squirrel in the genus Sciurus native to the eastern and midwestern United States, and to the southerly portions of the eastern provinces of Canada...

s, chipmunk

Chipmunk

Chipmunks are small striped squirrels native to North America and Asia. They are usually classed either as a single genus with three subgenera, or as three genera.-Etymology and taxonomy:...

s, raccoon

Raccoon

Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

s and opossums.

Threats

The dominance of oak in this part of the pre-Columbian savannas of North America

Pre-Columbian savannas of North America

Pre-Columbian savannas once existed across North America. These were created and maintained in a fire ecology by Native Americans until the 16th century death of most natives. Surviving natives continued using fire to clear savanna until European colonists began colonizing the eastern seaboard...

 was due to frequent fires. The fire suppression policies since the 1930s have been a significant forest disturbance.

Today there is very little intact habitat in this ecoregion, with a reduction of bottomland hardwood forest

Bottomland hardwood forest

The Bottomland hardwood forest is a type of deciduous hardwood forest found in broad lowland floodplains along large rivers and lakes. They are occasionally flooded, which builds up the alluvial soils required for the Gum, Oak and Bald Cypress trees that typically grow in this type of biome...

s by 70-95%, and only 0.02 percent of the original oak savannas remain. Although much of the area is forested, these forests tend to be highly fragmented and significantly altered by development, agriculture, and fire suppression. The forests are dominated primarily by oak and hickory species, but succession

Secondary succession

Secondary succession is one of the two types of ecological succession of plant life. As opposed to the first, primary succession, secondary succession is a process started by an event that reduces an already established ecosystem Secondary succession is one of the two types of ecological...

 has filled the understory with maple

Maple

Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...

s and yellow poplar and blocking oak regeneration. In some areas, habitat is threatened by urbanization and invasive species such as non-native privet

Privet

Privet was originally the name for the European semi-evergreen shrub Ligustrum vulgare, and later also for the more reliably evergreen Ligustrum ovalifolium , used extensively for privacy hedging. It is often suggested that the name privet is related to private, but the OED states that there is no...

, honeysuckle

Honeysuckle

Honeysuckles are arching shrubs or twining vines in the family Caprifoliaceae, native to the Northern Hemisphere. There are about 180 species of honeysuckle, 100 of which occur in China; Europe, India and North America have only about 20 native species each...

, garlic mustard

Garlic Mustard

Garlic mustard is a biennial flowering plant in the Mustard family, Brassicaceae. It is native to Europe, western and central Asia, and northwestern Africa, from Morocco, Iberia and the British Isles, north to northern Scandinavia, and east to northern India and western China...

 and kudzu

Kudzu

Kudzu is a plant in the genus Pueraria in the pea family Fabaceae, subfamily Faboideae. It is a climbing, coiling, and trailing vine native to southern Japan and southeast China. Its name comes from the Japanese name for the plant, . It is a weed that climbs over trees or shrubs and grows so...

. Significant natural areas in the ecoregion include: Wolf River (Tennessee)

Wolf River (Tennessee)

The Wolf River is a alluvial stream in western Tennessee and northern Mississippi, whose confluence with the Mississippi River was the site of various Chickasaw, French, Spanish and American communities and forts that eventually became Memphis, Tennessee....

, the Cedar glades

Cedar glades

A cedar glade is a habitat type unique to the central eastern United States. Cedar glades occur where limestone bedrock occurs near or at the surface. The glade areas proper have very shallow soil or exposed bedrock in some areas. Because of the shallow soil and the extreme conditions created by...

 and the western Highland Rim

Highland Rim

The Highland Rim is a geographic term for the area in Tennessee surrounding the Central Basin. Nashville is largely surrounded by higher terrain in all directions....

 of Tennessee; Mammoth Cave National Park; the Land Between the Lakes National Recreation Area

Land Between the Lakes National Recreation Area

The Land Between The Lakes National Recreation Area is a United States National Recreation Area located in Kentucky and Tennessee between Lake Barkley and Kentucky Lake. The area was designated a national recreation area by President John F. Kennedy in 1963...

 of Tennessee and Kentucky; Hoosier National Forest

Hoosier National Forest

The Hoosier National Forest, in the hills of south central Indiana, is a property managed by the United States Forest Service. Composed of four separate sections, it has a total area of . It is headquartered in Bedford, with a regional office in Tell City...

 and Yellowwood State Forest

Yellowwood State Forest

Yellowwood State Forest, originally Beanblossom Land Utilization Project, is a state forest located in Brown County, Indiana, near the more famous Brown County State Park. The forest features seventeen different areas within Brown County, comprising in total...

 in southern Indiana

Indiana

Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

; the Edge of Appalachia Preserve in Ohio

Ohio

Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

; the Cache River (Illinois)

Cache River (Illinois)

The Cache River is a waterway in southernmost Illinois, in a region sometimes called Little Egypt. The basin spans and six counties: Alexander, Johnson, Massac, Pope, Pulaski and Union. Located at the convergence of four major physiographic regions, the river is part of the largest complex of...

 wetlands and the Shawnee Hills

Shawnee Hills

The Shawnee Hills is a region of Southern Illinois that rests mainly in an east-west arc roughly following the outline of the southern end of the Illinois Basin. Whereas Mississippian and Pennsylvania Age rock layers are deep beneath the surface in central Illinois, these strata pierce the surface...

 in southern Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

; and the Ozarks in Missouri

Missouri

Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

 including Mark Twain National Forest

Mark Twain National Forest

Mark Twain National Forest is a U.S. National Forest located in the southern half of Missouri. MTNF was established on September 11, 1939. It is named for author Mark Twain, a Missouri native. The MTNF covers approximately 1.5 million acres , 78,000 acres of which are Wilderness, and National...

. The best preserved of these are Mammoth Cave, Edge of Appalachia, and parts of the Missouri Ozarks and the Tennessee Cedar Glades.