Presented here are brief descriptions of 35 naturally occurring vegetative cover types that were used to characterize prevailing vegetation of Ecoregion "sections" of the conterminous United States. Cover types may be visualized as the general, natural vegetation viewed from an aerial perspective. These cover types are used for descriptive purposes in the section narratives and should not be confused with potential natural vegetation (PNV), which was used in the process of identification and delineation of larger ecological units. Some cover types are similar to PNV, particularly in forested regions. Other cover types, such as the prairie type, are present only in small areas that have been changed to agricultural type. For example, cover types may result from exclusion of some types of natural disturbance, such as fire, and include planned disturbances, such as harvesting.
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WHITE-RED-JACK PINE
COVER TYPES
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Physiography
The white-red-jack pine cover type occurs generally on smooth to irregular plains and tablelands of northern Lake states and parts of New York and New England. More than 50 percent of the area is gently sloping.
Climate
Precipitation averages 25-45 inches annually and is distributed rather evenly throughout the year. Normal pan evaporation is 30-35 inches. During the frost-free season of 120-140 days, precipitation is roughly equal to evaporation.
Vegetation
Forests in which 50 percent or more of the stand is eastern white pine, red pine, or jack pine, singly or in combination, represent the white-red-jack pine cover type. Common associates include oak, eastern hemlock, aspen, birch, northern white-cedar, and maple. Much of this cover type is included in Kuchler's Great Lakes pine forest community.
Fauna
The white-tailed deer and black bear are the most common larger mammals in this cover type, and the moose inhabits the extreme northern portion. The woodland caribou formerly was abundant. In times past, the eastern timber wolf was very numerous and fed on small animals and the larger mammals just mentioned, but it has become very scarce and is classified as an endangered species.
The coyote, bobcat, great horned owl, and hawks are among current predators. The snowshoe rabbit and other small forest mammals are the main food source of the predators already mentioned. Spruce grouse and ruffed grouse inhabit the cover type. Porcupines inhabit parts of the cover type and become a problem in forest management when they are overly abundant.
Birds
Breeding bird populations average about 153 pairs per 100 acres. The black-burnian and the black-throated green warbler are the most abundant. Other birds include the whippoorwill, crested flycatcher, wood pewee, white-breasted nuthatch, veery, tanagers, ruffed grouse, great horned owl, pileated woodpecker, hairy woodpecker, downy woodpecker, blue jay, chickadees, red-eyed vireo, black-and-white warbler, ovenbird, redstart, black-throated blue warbler, hermit thrush, magnolia warbler, Canada warbler, yellow-bellied sapsucker, olive-sided flycatcher, red-breasted nuthatch, brown creeper, winter wren, blue-headed vireo, myrtle warbler, slate-colored junco, and white-throated sparrow. The endangered Kirtland's warbler occurs in limited areas.
Soils
The cool, moist soils are predominantly Spodosols. They have a low supply of bases and a horizon in which organic matter and compounds of iron and aluminum have accumulated, but they have no dense, brittle, or indurated horizon (Haplorthods).Soils of a significant proportion of the cover type are moist throughout the year and coarse textured,and they lack pedogenic horizons (Udipsamments).
Land Use
Nearly all of the land is forested and is used principally for lumbering and recreation. The associated cropland is devoted largely to growing potatoes and forage for dairy cattle. Large urban areas characterize the northeastern portions.
Data Source: United States Department of Agriculture, Forest Service
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THE OAK-HICKORY
COVER TYPE
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Physiography
The oak-hickory cover type occurs in areas of the eastern United States that are more mesophytic than surrounding areas. It reaches from southern Maine to Lake Huron and to southern Texas.
Its most continuous area is known as the Ozark Plateaus with extensions (Cross Timbers) into the semiarid grasslands of the southern Great Plains and the interior low plateaus that fuse with the glacial till plains south of the Great Lakes and extend westward around the Ozark Plateaus (immediately west of the central Appalachian Highlands). This cover type also occurs on the uppermost limits of the Appalachian Highlands, known as the Blue Ridge and the valley and ridge provinces of these highlands. These areas are geologically the oldest uplifts in the United States.
Geography
The Ozark Plateaus and their extensions comprise an area of 72,000 square miles west of the Mississippi River and south of the Missouri River. They consist of plateaus, variously dissected, and of strong rock. Much of the area is steep and lies at altitudes of 1,000-2,000 feet. Narrow belts of physiographically similar areas extend as far south as Texas and New Orleans and, along streams, north into Iowa. The interior low plateaus and their extensions lie east and north and extend westward around the Ozark Plateaus. These plateaus are similar to the Appalachian provinces in that the rocks and soils are highly weathered. The extensions are more characteristically glacial till plains.
The Blue Ridge and the valley and ridge provinces are Appalachian Mountain belts west of the Piedmont. The mountains are remnants of a former highland. Most of the rocks are old, strong,and of highly complex structure. These provinces are characterized by "folded" mountains in which resistant strata form ridges and weaker rocks are worn down to lowlands.
The oak-hickory cover type also includes the Black Belt, which is the richest and best known lowland on the East Gulf Coastal Plain. It is so named because of the deep, black residual soil. The belt varies from 20-25 miles wide from near the Georgia border, west through Alabama, and north through Mississippi. Its altitude varies from 200-400 feet. Rivers cut through the belt; there are few smaller streams.
Climate
Temperatures vary considerably in this cover type. The frost-free season is about 120 days in the northern portion and almost 300 days in southern Texas. In most of the area, the frost-free season ranges from 160-200 days. Annual precipitation ranges from less than 30 to more than 50 inches, averaging 35-45 inches. More than half of the precipitation falls in the warmest months. In many areas, potential evaporation during the warmest months is about equal to the precipitation.
Vegetation
The oak-hickory cover type varies from open to closed woods with a strong to weak understory of shrubs, vines, and herbaceous plants. By definition, oak and hickory must make up 50 percent of the stand, singly or in combination. The cover type includes six vegetation communities: the Black Belt on the Coastal Plain in Alabama and Mississippi, the oak-hickory forest and the mosaic of the oak-hickory forest and bluestem prairie communities of the Ozark Plateaus and interior low plateaus and their extensions, the oak forest of the Appalachians, the oak savanna, and Cross Timbers.
Sweetgum and red cedar are close associates in the southern (Black Belt) region of the cover type. Maple, elm, yellow-poplar, and black walnut often are close associates in eastern and northern parts of the oak forest and the oak-hickory-bluestem mosaic. The major shrubs are blueberry, viburnum, dogwood, rhododendron, and sumac. The major vines are woodbine, grape, poison ivy, greenbrier, and blackberry. Important herbaceous plants are sedge, panicum, bluestem,lespedeza, tick clover, goldenrod, pussytoes, and aster; many more are abundant locally.
Fauna
The fauna of the oak-hickory cover type is similar to that of other eastern hardwood and hardwood-conifer areas and varies somewhat from north to south. Important animals in the cover type include the white-tailed deer, black bear, bobcat, gray fox, raccoon, gray squirrel, fox squirrel, eastern chipmunk, white-footed mouse, pine vole, short-tailed shrew, and cotton mouse.
Bird populations are large. The turkey, ruffed grouse, bobwhite, and mourning dove are game birds in various parts of the cover type. Breeding bird populations average about 225 pairs per 100 acres and include some 24 or 25 species. The most abundant breeding birds include the cardinal, tufted titmouse, wood thrush, summer tanager, red-eyed vireo, blue-gray gnatcatcher, hooded warbler, and Carolina wren. The box turtle, common garter snake, and timber rattlesnake are characteristic reptiles.
Soils
The soils of this cover type are varied. The northeastern oak-hickory forest and the northeastern portion of the Appalachian oak forest are on Inceptisols and Ultisols. Soils of the smaller Black Belt area are largely Ultisols. The soils of the largest community in the cover type, the oak-hickory forest, are mainly Mollisols and Alfisols in the north and Ultisols in the central portion. Two "fingers" of the oak-hickory forest reaching into southern Texas coincide with areas of Alfisols; Vertisols on all sides are in other cover types.
Land Use
Small general farms characterize much of the area, but there are also large dairy and livestock farms. Tobacco is an important cash crop in the east and cotton is important in the west. The steeper slopes, accounting for almost half the area, are mainly in forest, which is used for both recreation and timber production. A large part of the nation's coal is mined in this cover type.
Data Source: United States Department of Agriculture, Forest Service
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THE MAPLE-BEECH-BIRCH
COVER TYPE
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Physiography
The maple-beech-birch cover type is best-developed in the New England States. Typically, it occurs on open high hills and low mountains. Only about 20-30 percent of the area is gently sloping. Ridges rise 500-3,000 feet above the broad valleys. Farther west, in the Lake States, the cover type occurs on irregular plains and tablelands. There, 50-80 percent of the area is gently sloping and local relief is normally 100-300 feet.
Climate
Mean annual precipitation ranges from 40-48 inches and is about 41 inches at central locations. The average annual snowfall of 72 inches covers the ground for about 87 days each year. The number of freeze-free days ranges from 120-150 per year. The mean daily maximum temperature is 24-36°F in January and74-80°F in July. The corresponding minimum temperatures are 4-18°F and 52-60°F. Potential evapotranspiration is 17-28 inches. The mean annual water surplus is 10-34 inches.
Vegetation
A forest is classified as being in this cover type when 50 percent or more of the stand is maple, beech, or yellow birch, singly or in combination. Common associates include hemlock, elm, basswood, and white pine.
Fauna
The white-tailed deer occurs throughout much of the maple-beech-birch cover type. The hardwood forest and the openings and farms within it provide food nd cover for a varied fauna. The black bear is present in many areas. The wolf is no longer common, but the red fox and gray fox are rather widespread, as is the bobcat. Several species of squirrels are in the forest, and a number of smaller rodents inhabit the forest floor.
The ruffed grouse is widespread, and the bobwhite inhabits the interspersed farmlands and forest openings. Songbirds include the ovenbird, red-eyed vireo, hermit thrush, scarlet tanager, blue jay,black- capped chickadee, wood pewee, and magnolia warbler.
Soils
Typical soils have a low supply of bases and a subsurface horizon that is dense and brittle but not indurated or that contains an accumulation of organic matter and iron and aluminum compounds (Fragiorthods and Haplorthods). Other major soils have light-colored surface horizons and a subsurface horizon that is dense and brittle but not indurated (Fragiochrepts).
Land Use
Much of the area is in farms. Feed grains and forage for dairy cattle are the principal crops. Potatoes are important locally. The steeper land is mainly forested, produces significant amounts of timber, and is an important recreation resource.
Data Source: United States Department of Agriculture, Forest Service
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