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This chapter is an edited version An Overview of the Physical of a manuscript by the same title Environment, Flora, and written by Edward W. Chester. Vegetation of Tennessee In addition to editing, some 2 material has been deleted from and some added to the original Instructormanuscript by the editors of this publication. Portions of the original manuscript were condensed from Guide to the Vascular Plants of Tennessee, compiled and edited by the Tennessee Flora Committee. Copyright © 2015 by The University of Tennessee Press, Knoxville. Used by permission granted to Edward W. Chester. See author’s notes for additional Tennessee information. of
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AUTHOR'S NOTES A more complete discussion of the topics in this chapter can be found in Chapter 1, “The Physical Environment of Tennessee” (written by Edward W. Chester) and Chapter 3, ”An Overview of the Vegetation of Tennessee” (coauthored by Hal R. DeSelm and William H. Martin) in the Guide to the Vascular Plants of Tennessee referenced at the beginning of this chapter. The contents of the two chapters are based on almost 200 combined years of study by the three authors and the nearly 100 references they cite. The authors are: Instructor
Edward W. Chester, Professor Emeritus of Biology and Botany, Austin Peay State University, Clarksville, Tenn.
Hal R. DeSelm (deceased), Professor Emeritus of Botany and the Graduate Program in Ecology, University of Tennessee at Knoxville. Dr. DeSelm died on July 12, 2011.
William H. Martin, Professor Emeritus of Biology and Director of the Division of Natural Areas, Eastern Kentucky University, Richmond. He served as Commissioner of Kentucky's Department for Natural Resources from 1992 to 1998. Tennessee of
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2 - 2 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee CONTENTS
INTRODUCTION 2-5 Overview of Tennessee Flora ...... 2-5 Characteristics of the Tennessee Flora...... 2-6 Vegetation of Tennessee...... 2-6 Copy
TENNESSEE CLIMATE 2-7 Temperatures and Length of Growing Season...... 2-7 Precipitation...... 2-8 Storms ...... 2-8 Microclimates...... 2-8
GRAND DIVISIONS OF TENNESSEE 2-9 Grand Division 1: West Tennessee...... 2-13 West Tennessee Phyisographic Province: The Coastal PlainInstructor...... 2-13 Mississippi River Valley Section...... 2-13 East Gulf Coastal Plain Section...... 2-14 Mississippi River Bluffs Subsection...... 2-14 West Tennessee Plain Subsection...... 2-15 West Tennessee Uplands Subsection...... 2-15 The Lower Tennessee River Valley...... 2-16 Grand Division 2: Middle Tennessee...... 2-17 Middle Tennessee Phyisographic Province: The Interior Low Plateau...... 2-17 Highland Rim Section...... 2-17 Western Highland Rim Subsection...... 2-17 PennyroyalTennessee Plain Subsection...... 2-18 Eastern Highland Rim Subsection...... 2-19 Centralof Basin Section...... 2-19 Outer Basin Subsection...... 2-19 Inner Basin Subsection...... 2-20 Grand Division 3: East Tennessee...... 2-22 East Tennessee Physiographic Province 1: The Appalachian Plateaus...... 2-22 Cumberland Plateau and Cumberland Mountains Subsection...... 2-22 East Tennessee Phyisographic Province 2: The Valley and Ridge...... 2-23 East Tennessee Phyisographic Province 3: The Blue Ridge (Unaka Mountains)...... 2-24
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2 - 4 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee INTRODUCTION
Tennessee is named for the former Cherokee town of Tanase (or Tanasi) in present-day Monroe County and for the river of the same name. Tennessee has 95 counties and borders 8 other states, which ties Missouri for the highest number. Extending from the Mississippi River on the west to the Blue Ridge Mountains on the east, the state is 440 miles long and 120 miles wide. Copy The total area is 26,443,500 acres, or about 42,146 square miles, making it the nation’s thirty-sixth largest state. Of that area, 926 square miles are covered by water. The lowest elevation of 178 feet above mean sea level (AMSL) is near Memphis (Shelby County), while Clingman’s Dome in Sevier County (at 6,643 feet AMSL) is the highest. The major rivers are the Mississippi, Tennessee, and Cumberland. This chapter describesInstructor the vegetation and plant communities of Tennessee and explores how they are related to the geography and physical environment of the state. It includes an overview of vegetation, climate, rivers, soils, topography, and even some history to help better understand how plant life is connected to so many other elements of the state’s natural environment. This information will provide a good foundation for grasping the information on soil, water, and plant management in later Tennesseechapters. Overview of Tennessee Flora A flora is defined as a compilation of known of plants in a specific area. The Tennessee flora has been studied for more than 300 years. Even with this long investment, our understanding of all the species and their distribution and relationships within the state is still incomplete. Even in areas where botanical field work has been extensive, some species have been overlooked or not yet described, and some regions remain to be thoroughly explored. In addition, the state’s flora is ever changing, with new native and nonnative elements moving University into the state along many migratory pathways. The potential impact of climatic changes is still unknown.
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 5 Human impacts (known as anthropogenic for listing, and more than 500 additional factors) have influenced the state’s flora and taxa are listed at the state level as elements of will continue to do so, in some cases leading conservation concern. The official state list was to habitat destruction and extirpation (the developed by the Natural Heritage Program disappearance of a species from an area). In of the Tennessee Department of Environment other cases, new habitats and migratory routes and Conservation (TDEC) with advice from a are opened. committee of botanists. The official state list also Important human factors include alterations identifies federally listed species. of rivers and streams, urban sprawl, pollution, Ten species are known to occur only within farming, mining, timbering, collection of Tennessee and are therefore termed endemic. plants for medicinal and nursery sales, and the Most of our endemics are found in the Central Copy introduction of nonnative organisms that attack Basin, the Cumberland Plateau, or in the Unaka or displace native populations. Such exotic Mountains, areas that will be defined later in pests may be plant pathogens (such as chestnut this chapter. Thirty-three previously known blight and Dutch elm disease), insects (such as species have not been documented for at least the hemlock woolly adelgid and emerald ash 20 years and are listed as extirpated. This is a borer), other invasive animals (such as wild constantly changing list, as taxa are added and boar), and numerous invasive plant species (such field work verifies the presence of taxa previously as Chinese privet and Amur honeysuckle). As a listed as extirpated. result of these and other factors not listed or not Naturalized and watch list taxa, state known, the state’s flora is constantly changing in and federallyInstructor listed elements, endemics, and number and distribution. extirpated species are identified in theGuide to Tennessee Vascular Plants and the University CHARACTERISTICS OF THE of Tennessee Herbarium website. This website TENNESSEE FLORA is continually updated and provides several Based on current data, 2,878 species of vascular thousand color images, a map showing the flora live in Tennessee, and 470 of these are known county distributions, and other woody (trees, shrubs, and woody vines). About valuable information. The USDA Plants 16% (447) of the flora are nonnative species Database website is also a valuable resource. that have been accidentally or deliberately For those interested in using native plants in introduced and are now well established landscaping, Gardening with the Native Plants (naturalized), reproducing and dispersing of Tennessee: The Spirit of Place, by M. Hunter, is without intentional human assistance. recommended (University of Tennessee Press). Some of the nonnativesTennessee (often referred to as exotics) have become invasive to the detriment VEGETATION OF TENNESSEE of native species and plant communities. The The vegetation of an area is usually defined as Tennessee Exoticof Pest Plant Council maintains the flora with the addition of information on categorized and ranked lists of invasive community structure and relationships. This nonnatives at its website. Many nonnative chapter uses the common names of plants species have been documented a few times for simplicity. A list of the scientific names of in the state but are not known to be widely plants referred to in this chapter may be found naturalized. These casual introductions are not on page 2-31. The use of scientific names is included as part of the state’s flora, but their quite important in botanical and horticultural presence is noted on a watch list. Naturalized fields for clarity and precision. (See Chapter 3.) and watch list categories are regularly revised Forest communities are used primarily to define when new information becomes available. the vegetation of an area, and the following Twenty-two of Tennessee’s plant taxa (a discussion adheres to that pattern. Universitygeneral term for taxonomic groups, such as Tennessee forests are composed mostly of order, family, genus, or species) are federally plants with flowers and fruits that bear seeds listed as endangered, threatened, or candidates (angiosperms). Most of them are deciduous
2 - 6 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee and occur across the state. In contrast, plants variation in elevation are key reasons that the that bear seeds in or on cones and do not have state has a wide range of climatic conditions. flowers or fruits gymnosperms( ) are mostly evergreen and usually occur in areas such as Temperatures and Length of • wetlands dominated by bald cypress Growing Season • shallow limestone soils with red cedar Tennessee climate varies with latitude and • exposed upland slopes with various altitude. USDA hardiness zones in the state species of pines range from 6a to 7b or even to 8a in urban • mesic coves, ravines, and along streams southern areas. (See Figure 1.) with hemlock • Memphis has an annual mean Copy temperature (AMT) of 62°F (40°F in • at higher elevations in the Unaka January and 83°F in July) with a growing Mountains with red spruce and Fraser fir. season of about 235 days. Some nonforested areas dominated by • Nashville has an AMT of 59°F (36°F in nonwoody plants occur throughout the state, January and 79°F in July) with a growing both on rock outcrops and shallow soils where season of 225 days. hot and dry extremes occur, and on deeper soils • Knoxville has an AMT of 60°F (41°F in without environmental extremes. January and 78°F in July) with a growing season of 220 days. TENNESSEE CLIMATE The AMT drops considerablyInstructor in The climate of Tennessee is generally temperate mountainous areas, with growing seasons as low with warm summers and mild winters. However, as 130 days (as determined by data from the UT the elongated geography of the state and its climate data site).
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FIGURE 1 University Tennessee hardiness zones.
Source: U. S. Department of Agriculture
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 7 Vegetative Features It is common to classify ecosystems based on plant species, which can encompass trees, shrubs, and herbaceous plants. These groupings are commonly designated by the major tree species, but these should not be assumed to be the only species present. As described in the text, many associates (Table 1) occur with these dominant species. There are several vegetative communities in Tennessee, as shown in Figure 5. In West and Middle Tennessee, the oak–hickory type forests cover much of the land area, while in East Tennessee, mixed mesophytic Copy forests and Appalachian oak forests often predominate. It is clear from Figure 5 that waterways, elevation, soil characteristics, and many other elements of physiography have an impact on vegetative features. Certainly much more can be stated about vegetation characteristics, but the purpose of this chapter is to provide an introduction and overview.
The average dates of the last spring freeze AverageInstructor annual snowfall varies from a few range from late March in the Memphis area to inches in the west (5 inches in Memphis), to early May in the Unakas. Average dates of the 10 inches in Nashville, up to several feet in the first fall freeze range from early October in the Cumberlands and Unakas. However, snow Unakas to early November in the Memphis area. cover rarely lasts for more than a few days except Prolonged periods (several days) of freezing at higher elevations where the ground may be weather are rare except in the mountains. Soils covered for several weeks or even months. rarely freeze to a depth of more than a few inches and then remain frozen for only a few Storms days. Severe thunderstorms with lightning, hail, heavy precipitation, and damaging winds are common, Precipitation mostly in spring through early autumn. Most precipitation occursTennessee as rain in winter and Tornados causing significant property and forest early spring. March is usually the wettest month, damage as well as human injuries are much and Septemberof and October are the driest. The more common in West and Middle Tennessee principal source of atmospheric moisture is the than East Tennessee. Remnants of Gulf Coast Gulf of Mexico, so precipitation is generally hurricanes regularly track the Mississippi and higher in southern areas. lower Tennessee River Valleys, resulting in Annual precipitation in West Tennessee flooding and wind damage. Deep snow and ranges from 46 to 54 inches, increasing from the ice storms are not common, but they can cause Mississippi River Valley to the West Tennessee severe forest damage when they do occur. Uplands. In Middle Tennessee, the Central Basin averages 45 inches and the Highland Rim about 50 inches per year. The Cumberland Microclimates Plateau averages 50 to 55 inches, while the Since much of the Tennessee topography Valley and Ridge province averages 40 inches consists of hills and mountains, with subsequent Universityin the north to over 50 inches in the south. The ridges, valleys, and varied slopes, local climatic highest peaks of the Unaka Mountains average conditions (microclimates) are an important about 80 inches. aspect of the physical environment. General
2 - 8 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee statements about temperature, precipitation, physiography. In this chapter, Tennessee’s and growing season are important, but the five physiographic provinces with sections flora (and fauna) of an area must be examined and subsections are the main area descriptor, in relation to existing microclimates. The but ecoregions are also noted. Ecoregion possibilities for research on Tennessee's living designations have been developed more recently natural resources and microclimates are than physiographic provinces. They focus on essentially endless. similarities in ecosystems and environmental resources. So, essentially, the same area can GRAND DIVISIONS OF be described using either of these systems — TENNESSEE physiographic provinces (with sections and Copy subsections) or ecoregions. This additional The (physical geography) of physiography descriptor has been included for your Tennessee is central to how we refer to parts information and to aid in future research. of the state even if we rarely use that term. The The following discussion approaches the three Grand Divisions of Tennessee —West, Grand Divisions of the state from west to east, Middle, and East — are recognized in the state constitution and in state law, and they are noting the generalized physiographic regions of represented on the state flag by three prominent the state: provinces, sections, and subsections stars. (Figure 2) as well as ecoregions and physical An area with similar terrain, rock characteristics. Figure 3 shows a broader view, types, geology, and history is referred to as illustrating how the physiographicInstructor provinces a physiographic province. These often large observed in Tennessee relate to those of provinces are usually divided into sections neighboring states. Figure 4 portrays graphically and subsections. Another common method the arrangement of vegetative features of the of dividing area is by ecoregions, areas having state. Table 1 lists common terms used in these similar soils, vegetation, climate, geology, and descriptions.
GRAND DIVISION 1 GRAND DIVISION 2 GRAND DIVISION 3 WEST TENNESSEE MIDDLE TENNESSEE EAST TENNESSEE
COASTAL PLAI I TERIOR LOW PLATEAU APPALAC IA VALLE A D RIDGE BLUE RIDGE P ISOGRAP IC PROVI CE P ISOGRAP IC PROVI CE PLATEAUS P ISOGRAP IC P ISOGRAP IC P ISOGRAP IC PROVI CE PROVI CE Tennessee PROVI CE
WESTER of IG LA D RIM EASTER IG LA D RIM
FIGURE 2 Physiographic Provinces, Sections, and Subsections of CUMBERLA D PLATEAU SECTIO MISSISSIPPI RIVER VALLE SECTIO IG LA D RIM SECTIO (I CLUDI G CUMBERLA D MOU TIA S) Tennessee. WESTER IG LA D RIM SUBSECTIO EAST GULF COASTAL PLAI SECTIO PE RO AL PLAI SUBSECTIO MISSISSIPPI RIVER BLUFFS SUBSECTIO
EASTER IG LA D RIM SUBSECTIO WEST TE ESSEE PLAI SUBSECTIO
WEST TE ESSEE UPLA DS SUBSECTIO CE TRAL BASI SECTIO (OUTER) NOTE: Illustration is not drawn to scale UniversityLOWER TE ESSEE RIVER CE TRAL BASI SECTIO (I ER)
Source: The Geologic History of Tennessee. State of Tennessee Dept. of Environment and Conservation, Tennessee Division of Geology. Bulletin No. 74.
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 9 TABLE 1 Common Terms Used to Describe Ecology and Soils in Tennessee Physiography
Terms Definitions and Application Information
Alluvium Sand, silt, clay, organic matter, and other materials moved and deposited by water. Because topsoil is often eroded and moved by water, alluvial areas can beCopy fertile and productive if not frequently flooded. Bottomland Low-lying land that is associated with a river or stream. Such areas commonly have alluvial soils and may be flooded. Chert A sedimentary rock, some also commonly call flint, which is derived from silica. Colluvium Materials that have moved downslope, often by gravity or by mass movement when wet. Dolomite A mineral made of calcium magnesium carbonate that is also used to describe sedimentary rocks containing dolomite. Dominant/Associate Dominant species are more numerous thanInstructor others in the area, while associates are species commonly found in lesser numbers with those dominant species. Fragipan A dense subsoil layer that restricts the flow of water and root growth. Karst A term used to describe a landscape that has limestone, dolomite, and other rocks that can be dissolved by water. Often there are caves, sinkholes, and underground drainage in areas with karst topography. This can have an impact on how the land is used and the soil-water relations of the area. Limestone A sedimentary rock made of various forms of calcium carbonate. Loess Deposits that are loosely compacted after being blown by wind. They are often primarily made of the mineral silt. (See Chapter 5.) Mesic, Xeric, Hydric (see Mesic refers to areas with moderate or well-balanced supplies of soil moisture. Figure 5) Xeric refers to dry areas, while hydric refers to wet areas. Species composition Tennesseevaries with both climate and soil moisture regimes. Residuum Soils that were formed at their current sites by weathering of underlying rock of parent material. Shale A fine-grained sedimentary rock that often has a high percentage of clay and silt minerals, (See Chapter 5.) Succession The progress from one composition of species to another. Commonly used to refer to the transition in species composition over time after habitat disturbance. Upland Land with higher elevation. Soils tend to be formed on site from underlying parent material or wind-blown materials rather than being moved by water or gravity. University
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FIGURE 3 Physiographic Instructorprovinces in the southeastern United States.
Source: Nelson, T.C., and W.M. Zillgitt. 1969. A forest atlas of the south. Southern Forest Exp. Station, New Orleans, LA., and Southeastern Forest Exp. Station, Asheville, NC.
B D D D D G B F H B D B G G D B A A B F G A B E H G H C G B Tennessee A B F B G H A B H B B E F H FIGURE 4 E I A G Vegetative features of C C A B of G H B B F Tennessee. B C E F A G C F C Source: Kuchler, A. W. 1964. Potential natural vegetation of the conterminous United States. Amer. A. Southern Floodplain Forest Geogr. Soc. Spec. Publ. No. 36. B. Oak–Hickory Forest 116 pp. C. Oak–Hickory-Pine Forest D. Mosaic of Bluestem Prairie and Oak-Hickory Forest E. Cedar Glades F. Mixed Mesophytic Forest G. Appalachian Oak Forest H. Northern Hardwoods University I. Southeastern Spruce–Fir Forest
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 11 Xeric Mesic White Oak/ Beech/ Copy Oak/Pine/ Sugar Maple/ Hickory Mown Lawn Oak/Pine/Hickory
Tulip Poplar Roadway Creek Sugarberry/ Elm/Green Ash Image revised from Miss. State Univ. Extension image in Hydric ‘Designing with native plants and naturalistic landscapes’.
FIGURE 5 Example of a landscape where different moisture regimes result in different vegetation. This figure shows dryer, upland sites (xeric), moderate moisture sites (mesic), and wet or Instructor bottomland sites (hydric).
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2 - 12 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee West Tennessee extends from the Mississippi River on the west to the lower Tennessee River on the east. Historically, the region was known as the Western District and belonged to the Chickasaw Indians. An 1818 treaty granted title to the region, but not all county boundaries were established until the 1870s. The landscape in West Tennessee does not contain large elevation differences and is similar to coastal regions to the south. In geological terms, the area is relatively young. Marine waters receded and left gravel, sand, and clay to form the current soils. The Obion, Forked Deer, Hatchie, Loosahatchie, and Wolf Rivers drain west into the Mississippi River, while the Big Sandy and several smaller streams drain east into the Tennessee River. Most people think of this area as cotton country, but diverse agricultural production of soybeans, corn, wheat, fruits, and vegetables also occurs. Except Copy for small areas near the Tennessee River, all of West Tennessee is within the Coastal Plain province.
West Tennessee soybeans, cotton, corn, wheat, vegetables, Physiographic Province: and even sod is produced. Levees and dikes The Coastal Plain help to prevent flooding, but overflows, backwaters, and tributary flooding still occur. The Coastal Plain Province begins just Vegetation Characteristics south of New England and extends around The vegetationInstructor in this section is classified as the coast into Texas. Within this large southern floodplain or bottomland hardwood, province, two sections occur in Tennessee. (Figure 4) and location of species is related to MISSISSIPPI RIVER VALLEY SECTION the flooding of the area. Bottomland forested General Description and Soil Characteristics areas are ecologically important for storing The Mississippi River Valley Section (the floodwaters as well as recycling nutrients and Northern Mississippi Alluvial Plain Ecoregion) preventing sediments and other wastes from is 14 miles wide and covers about 99 square reaching open rivers and streams. There are
GRAND DIVISION 1: WEST TENNESSEE GRAND DIVISION 1: WEST miles with elevations ranging from 178 to 300 reports that the area included heavily timbered feet AMSL. Between the Mississippi river on swamps in the mid-1800s, but only remnants the west and bluffs on the east, this section exist today. In areas that are permanently or includes all of Lake, western Obion, portions frequently flooded, bald cypress dominates of Dyer and Lauderdale,Tennessee and a narrow strip of or is codominant with water tupelo, and Tipton and Shelby counties. The landscape those species are associated with red maple, includes extensive agricultural fields, bayous, black willow, and green ash. swamps, riverof terraces, oxbow lakes, meander The meandering tributaries of the scars, and natural and man-made dikes and Mississippi River have broad valleys and some levees. Reelfoot Lake, formed by earthquakes flooded depressions. Bald cypress, river birch, in 1811 to 1812, is the largest natural lake in sweetgum, sycamore, black willow, overcup and Tennessee and a well-known natural landmark. cherrybark oaks dominate the wettest areas. The entire area is within the floodplain In areas with less flooding and better drainage, of the Mississippi River and has deep soils green ash; swamp chestnut; white, cherrybark, composed of gravel, sand, silt, and clay (see and willow oaks; red maple; slippery elm; and Chapter 5) that were deposited by water. (See shellbark hickory are common. alluvium in Table 1). Soils vary from silty Across the landscape and flooding or loamy and well-drained on flat areas to gradients, a range of oak species occur. Overcup Universityclayey and poorly drained on the numerous oak–water hickory communities with green wet areas. This is one of Tennessee’s most ash, sugarberry, red maple, swamp privet, and productive agricultural areas, one in which sweetgum are found in areas with prolonged
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 13 sugarberry, and sycamore–green ash–sugarberry species. An understory of giant cane is common. Herbaceous plants, studied mainly at Reelfoot Lake, include submerged, floating, and emergent species. (Emergent species are those whose roots are submerged but the rest of the plant extends out of the water.) Major submerged species are pondweed, coontail, and bladderworts. Floating species are American lotus, water-lily, yellow pond- lily, and water-shield. Emergent species Copy forming dense stands include giant cut-grass, several species of smartweed, pickerelweed, lizard’s tail, water willow, mallows, and cattail. Shrub-dominated communities (those composed of buttonbush, swamp privet, and sandbar willow) are part of the transition from water to forest and exist as marshy patches in forest interiors. Stands of scouring rush also occur in many roadside ditches. EAST GULFInstructor COASTAL PLAIN SECTION Sometimes referred to as the Plateau Slope, the East Gulf Coastal Plain extends from the Mississippi River Valley to (or nearly to) the Tennessee River and has three subsections.
Mississippi River Bluffs Subsection General Description and Soil Characteristics (Bluff Hills is part of the Mississippi SOURCE: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org Valley Loess Plains Ecoregion) Water tupelo Covering about 850 square miles, the (Nyssa aquatica) steep bluffs of the Mississippi River Bluffs stand annual flooding. Wet Tennesseebut less flooded sites Subsection form the eastern river valley border. are dominated by swamp chestnut; swamp The four most prominent bluffs are called white, cherrybark, pin, water, and willow oaks; the Chickasaw Bluffs and were named and silver and redof maples; green ash; box elder; numbered by early boatmen and fishermen. They stretch from north to south, with Bluff sugarberry; and pecan. On the highest locations 1 being in Lauderdale County and Bluff 4 in with only brief flooding, bottomland and Shelby County. The city of Memphis actually moderate moisture species (see mesic in Table sits on Bluff 4 at one of the few places where 1) such as white and cherrybark oaks, sugar the bluffs and the Mississippi River meet. maple, beech, tulip poplar, and basswood occur. The bluffs stand about 100 feet above the On point bars and natural levees along valley and are covered with yellowish-brown the Mississippi River, annual flooding results windblown deposits (see loess in Table 1) in shifting, sandy substrates dominated by that may be as much as 80 feet thick. Loess successional forests composed mainly of deposits are a parent material from which cottonwood and black willow. With increasing soils are formed with different characteristics Universityland stability, the forests are characterized by from nearby alluvial soils. Erosion is forest communities such as pecan–sugarberry– commonplace on these bluffs, and extensive slippery elm, green ash–American elm– areas are covered with invasive kudzu.
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SOURCE: Rob Routledge, Sault College, Bugwood.org Tulip poplar (Liriodendron tulipifera) leaf and Vegetation Characteristics about 250 to 500 feet in elevation are broken flower The bluffs and steep slopes are mesic by meandering streams and rivers. Most soils environments and have vegetation unlike the are derived from gravel, silt, sand, and clay nearby floodplains. Forests on the deep, well- covered with loess at a depth varying from 30 drained loess soils and protected eroded sites of to 80 feet near the bluffs down to 3 feet on the bluffs are actually quite similar to forests of the eastern edge. Drainage is generally good, the Cumberland Plateau. An exampleTennessee is within but there are some restrictive subsoil layers the 4,000-acre Meeman-Shelby Forest Natural that interfere with water movement. (See Area, where the bluff forests contain beech, tulip fragipans in Table 1.) Erosion is noticeable in poplar, sweetgum, and variousof red and white many areas. The rolling to level topography oaks. There are many shrub and herbaceous supports production of soybeans, corn, species in distinctive combinations, including a cotton, vegetables, tree fruits, and livestock. high density of red buckeye and hop hornbeam. West Tennessee Uplands Subsection West Tennessee Plain Subsection General Description and Soil Characteristics General Description, Soil, and (Southeastern Plains and Hills, part of Vegetation Characteristics the Southeastern Plains Ecoregion) (Loess Plains, part of the Mississippi The West Tennessee Uplands Subsection is Valley Loess Plains Ecoregion) about 12 miles wide in the north to about 40 The broad West Tennessee Plain Subsection, miles wide at the southern end and covers about Universitycovering 4,100 square miles, extends east from 4,300 square miles drained by the Tennessee the Mississippi River Bluffs to the headwaters River. Elevations are commonly around 500 feet, of streams that drain west. Gently rolling plains and the landscape is more dissected and rolling
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 15 than that of the plains to the west. Soils may be loamy, silty, or clayey, and erosion is common. Most are well drained, but the best croplands are on the stream bottoms and terraces. Massive clay deposits, especially in Henry County, are mined and the clay used for making bricks, pottery, and ceramics. These deposits are also known worldwide for yielding fossils of plants now known to occur only in the tropics. Most tillable land is used for corn, soybeans, grain sorghums, vegetables, cotton, hay crops, or pasture. Copy Vegetation Characteristics Upland forests have dominant white, southern red, chestnut, post, and black oaks with pignut and mockernut hickories on drier sites along with persimmon, blackgum, and slippery and winged elms. The driest, upper slopes with sandy soils (mostly in the south-central and southeastern parts of the province) may be dominated by shortleaf pine. Loblolly pine was widely plantedInstructor as a soil conservation measure after World War II but has been extensively logged by the pulp industry since then. Sites with more moderate moisture (see mesic in Table 1) on lower and northern slopes and in draws and ravines are dominated by white oak and beech with associated sweetgum and tulip poplar. Lower slopes and stream terraces also have American elm, shellbark hickory, and water, chinquapin, and Shumard oaks.
SOURCE: Carol Reese, University of Tennessee THE LOWER TENNESSEE RIVER VALLEY Winged elm The floodplain of the lower Tennessee River, (Ulmus alata) Tennesseealso known as the Western Valley, is sometimes considered a separate physiographic unit. Before dams impounded the river, floodplains of could stretch to several miles wide. However, the 1944 building of the high dam at Gilbertsville, Kentucky, formed the Kentucky Reservoir and covered many bottomlands.
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2 - 16 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee Middle Tennessee extends from the Tennessee River and Kentucky Reservoir on the west to the Cumberland Plateau on the east. Elevation ranges from nearly level on the Pennyroyal Plain and in the Central Basin to typical Tennessee "hill country" on the Western and Eastern Highland Rims. Many forests remain, but agriculture is common. Military installations, the automobile and equine industries, and the cities and suburbs around Nashville add significantly to the economics of the area. All of Middle Tennessee is within one physiographic province. Copy Middle Tennessee and surrounding forests were decimated to Physiographic Province: produce charcoal required to melt the iron The Interior Low Plateau in the ore. Phosphate mining was also an important industry around Maury County This Middle Tennessee Province includes during the first half of the twentieth century. central Kentucky and Tennessee and smaller Soils on slopes were formed from limestone areas in Alabama, Illinois, Indiana, and Ohio. and have clayey subsoils with some chert. (See The Cumberland and Tennessee Rivers and Table 1.) Hill soils were formed from thin loess some of their tributaries are the primary and limestone, while creek and river bottoms waterways and flow into the Ohio River. are a rich, silty alluvial soil. Tillable lands are more commonInstructor northward and devoted to HIGHLAND RIM SECTION soybeans, corn, tobacco, and some specialty Covering about 12,600 square miles in crops as well as livestock and hay. Southward, Tennessee, Kentucky, and Alabama, the timber is more common, and forests cover Highland Rim is basically a ridge that surrounds much of the area. (Wayne County is the an eroded dome called the Central Basin. It most heavily forested county in the state.) contains three subsections. Vegetation Characteristics Western Highland Rim Subsection Ridges and upper slopes include chestnut, post, (Western Highland Rim and Western scarlet, and blackjack oaks, often with pignut Pennyroyal Karst Ecoregions) and mockernut hickories. On the driest ridges
GRAND DIVISION 2: MIDDLE TENNESSEE GRAND DIVISION 2: MIDDLE General Description and Soil Characteristics and slopes, Virginia and shortleaf pines may The Western Highland Rim is a broad plateau occur. (These forests are examples of oak– tilted slightly from eastTennessee to west that has dissected hickory and oak–hickory–pine forests; see terrain and many stream valleys. Covering about Figure 4 and the "Vegetative Features" box on 7,500 square miles, this subsection includes page 2-8.) On the more moist uplands, white some countiesof adjacent to the Tennessee River oak shares dominance with northern red oak, as well as several Middle Tennessee counties. beech, tulip poplar, and sugar maple. Lower Elevations range from 400 to 1,000 feet, with slopes with moderate moisture are dominated the highest points being in Giles, Lawrence, by white, black, and southern red oaks, as well and Wayne Counties. Western and southern as pignut and shagbark hickories. On lower portions are drained by the Duck, Buffalo, and and protected sites, beech, northern red oak, Elk Rivers flowing into the Tennessee River. The tulip poplar, sugar maple, and black walnut are northern portion is drained by the Cumberland most common. Floodplains are dominated by River, which flows into the Ohio River. sycamore, silver maple, sweetgum, box elder, and The area has developed primarily on cottonwood, often with an understory of giant limestone with some gravel and shales. Iron- cane. Universitybearing ores led to a major iron mining and Eastern red cedar is common in processing industry in the 1800s to early 1900s. abandoned fields that are allowed to regrow In 1873 there were 11 furnaces “in blast,” and is sometimes found with Virginia or
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 17 shortleaf pines (or both). Cedar may also of large animals and by periodic fires set by be prominent on limestone river bluffs, Native Americans. usually with chinquapin oak, blue and white Vegetation Characteristics ashes, and winged elm. In addition to these The Big Barren grasslands were and are forest communities, open glades on shallow, dominated by native perennial grass species calcium-rich soils and open forests dominated similar to those in midwestern prairies. On by stunted chinquapin oak and red cedar medium-moisture to dry sites, little bluestem, are found near the Tennessee River. Indian grass, and big bluestem are the major Pennyroyal Plain Subsection species with some panic grasses. Switchgrass (Western Pennyroyal Karst Ecoregion) is more prevalent with big bluestem on more Copy General Description and Soil Characteristics mesic sites, while the wettest (hydric) sites Frequently referred to as the "Pennyrile," the have eastern gama-grass and various rushes Pennyroyal Plain is mostly in Kentucky but and sedges as their dominant species. With extends into parts of Stewart, Montgomery, European settlement, most of the barrens were Robertson, Sumner, and Cheatham counties. quickly converted into farmland that today The flat to rolling, mostly nonforested karst produces soybeans, corn, wheat, and tobacco region (see Table 1) is often referred to as (especially the dark-fired type) and is the site of the Big Barrens. Early settlers referred to it as beef and dairy farms. Few grasslands exist today. “barrens,” apparently because of the grass cover Swamp and wet forests were once and large treeless areas. Such grasslands once common in Pennyroyal depressions and on covered thousands of acres and probably became poorly drainedInstructor soils, but logging and draining established under dryer climates. They may have for agriculture reduced them. Existing sites been maintained by the grazing and trampling are dominated by oaks, including willow, Little bluestem (Schizachyrium scoparium) SOURCE: Carol Reese, University of Tennessee
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2 - 18 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee overcup, cherrybark, pin, and several other scarlet, white, blackjack, and post oaks. More oak species, along with red maple, sweetgum, mesic flat to rolling lands and middle and lower cottonwood, and swamp cottonwood. hill slopes are dominated by white and black oaks with pignut, bitternut, and mockernut Eastern Highland Rim Subsection hickories, along with red maple and blackgum. (Eastern Highland Rim Ecoregion) North-facing and lower elevation slopes as well General Description and Soil Characteristics as more protected dissected areas are dominated The Eastern Highland Rim Subsection is the by mesic forests of sugar maple, beech, tulip eastern continuation of the Western Rim, poplar, yellow buckeye, and white oak, often completing the circle around the Central Basin. with northern red oak, red maple, blackgum, Compared to the Western Rim, there is more and hickories. Examples of mixed mesophytic Copy level (tableland) terrain, but also more rugged forests (see Figure 4 and the "Vegetative terrain toward the edge of the Cumberland Features" box on page 2-8) with beech, Plateau. Numerous narrow valleys, some with tulip poplar, sugar maple, white oak, black waterfalls, cut into the Eastern Rim. The walnut, yellow buckeye, white basswood, and transition region between the Eastern Rim and cucumber tree are on the most protected sites. the Central Basin is rough and dissected because On steep limestone cliffs with thin soils of stream erosion. that are mostly found along rivers, forests are The Eastern Rim averages 25 miles across dominated by red cedar and by chinquapin with a total area of about 2,500 square miles. and Shumard oaks. Bottomland forests include Elevations generally range from 800 to 1,300 silver maple, box elder, sweetgum, river birch, feet and average about 1,000 feet. Short red maple, sycamore, andInstructor slippery elm. Swamp Mountain (in Cannon County), an outlier forests occur in depressions where there are of the Cumberland Plateau, is over 2,000 high water tables, slowly drained soils, or yearly feet high. Water is drained primarily by the flooding. Wetland species found there include Cumberland, Caney Fork, Obey, Roaring, and overcup, willow, water, and pin oaks as well Wolf Rivers in the north and by the headwaters as white oak and red maple. Disturbed area of the Duck and Elk Rivers in the south. forests have a mixture of species that include Common underlying materials are hickories, white ash, red maple, and hackberry. limestone, chert, shale, and dolomite. (See CENTRAL BASIN SECTION Table 1.) An extensive karst region centered (Outer and Inner Nashville Basin Ecoregions) in Warren and White Counties has numerous The Central Basin extends almost to the caves and sinkholes. Soils were mostly formed Kentucky line on the north and slightly into from cherty limestone and are strongly acid TennesseeAlabama on the south. Approximately 50 miles and low in fertility. Lower slopes have shallow wide and 120 miles long, the basin covers about soils over shale rocks, while loess-derived soils 5,500 square miles and resulted from erosion are found on some ridges.of Forests are extensive of the Nashville Dome, causing a depression in most areas and timber is still important. carved out of solid limestone. Northern areas are Scattered barrens, many now converted to drained by the Cumberland, Harpeth, Stones, agricultural land, are especially common and lower Caney Fork Rivers, and southern in Coffee, Cannon, and Warren Counties. areas by the Duck and Elk Rivers. Most Tillable lands support tobacco production recognize an outer and inner basin as described (mostly of the burley type), pastures and and mapped by the late H.R. DeSelm in 1959. livestock, and fields of small grains, corn, and soybeans. In addition, the Warren County area Outer Basin Subsection is home to a significant nursery industry. General Description, Soil, and Vegetation Characteristics Vegetation Characteristics UniversityUpland areas of the Eastern Rim are primarily Steep hills and narrow valleys are common and covered by oak forests. Divided or steeper average 750 feet in elevation, but some hills rise landscapes include chestnut, southern red, to 1,300 feet. Limestone, chert, and shale are
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 19 all common underlying rocks. Soils are mostly Inner Basin Subsection well drained but vary in depth. Many soils can General Description and Soil Characteristics be basic in these regions because they were The now very urban Inner Basin area is mostly formed from the underlying limestone rocks. rolling or flat with poor surface drainage, Level upland soils are productive, especially for karst features, and much exposed limestone. pasture, hay, and forests, with some row crops, Broad flat areas with sheets of limestone including corn, soybeans, and burley tobacco. and shallow soil are referred to as cedar or Ridges and dry slopes are occupied limestone glades. Soil depths range from a by secondary oak–hickory forests with few inches in cedar glades (often none on flat chestnut, white, southern red, northern red, exposed limestone) to several feet near rivers. black, and scarlet oaks, along with pignut Copy and shagbark hickories. On north-facing Vegetation Characteristics slopes and other more moist sites, oaks and Forest vegetation is mostly cedar with hickories are prominent but beech, tulip hackberry; blue and white ashes; chinquapin, poplar, sugar and red maples, and white ash Shumard, white, and red oaks; and hickories. are also present. Terraces and bottomlands Disturbed sites now have sugar maple, white are characterized by sycamore, sweetgum, red ash, and cedar as dominant species, with Tennessee milk maple, green ash, box elder, and willow oak. hackberry; sugarberry; slippery and winged vetch (Astragalus elms; northern red, chinquapin, and Shumard tennesseensis) growing in the cedar glades oaks; shagbark hickory; Osage orange; and blackgum. Mesic sites include more sugar maple, SOURCE: Natalie Bumgarner, University of Tennessee beech, and tulipInstructor poplar. Along streams and in bottoms, silver maple, box elder, sycamore, red maple, and green ash are common. Cedar glades are one of the unique vegetation features of Tennessee, and fortunately several are now state-owned and protected. Their importance has been documented by the lifetime work of Dr. Elsie Quarterman (1910–2014) of Vanderbilt University, followed by decades of work by her students, Drs. Jerry and Carol Baskin (University of Kentucky). The surface is often an open area of rock, gravel, Tennesseeand shallow soils less than 2 inches deep. Their studies show that glade microclimates select for herbaceous species that can survive long growing of seasons, high light, extended drought, limited soil, and extreme soil and air temperatures. Vegetation types in inhospitable glade environments is largely determined by soil depth (including soil accumulation in cracks of the rocks). Glades can be bare or they may be occupied by low-growing mosses, lichens, or herbaceous vegetation, or by scattered individuals and small stands of small eastern red cedar. Such glades are home to a number of endemic species, like the Tennessee University coneflower and Tennessee milk vetch. Exposed gravels are dominated by winter annuals. With more soil development,
2 - 20 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee winter annuals are joined by perennials, and with increasing soil depth, perennial grasses begin to appear. Surrounding the glades and where the soils are deep enough to be occupied by trees, there are thickets of cedar or cedar-deciduous forests with redbud, winged elm, and post, chinquapin, and Shumard oaks as major associates. Copy
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An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 21 The East Tennessee Grand Division extends from the western edge of the Eastern Highland Rim to the eastern state line. It is a region of great contrast that traverses the scenic Cumberland Plateau with its natural bridges, rockhouses (openings at the base of a cliff that resemble a cave), and breath-taking vistas, through the valleys and ridges of East Tennessee and finally to the mountains and coves of the Unakas. Parts of three physiographic provinces are included in this division.
East Tennessee bridges are distinctive features in the northern Copy Physiographic Province 1: areas. Much of the Plateau interior is poorly The Appalachian Plateaus drained. It contains a number of natural ponds, Extending from New York to Alabama, swamps, and wet meadows as well as two The Appalachian Plateaus Province major valleys. The Sequatchie Valley is more crosses Tennessee from north to south. It than 60 miles long and 4 to 5 miles wide with is a geologically old plateau with several escarpments nearly 1,000 feet tall on each side. sections that differ in underlying rock, The smaller Elk Valley is to the north of the Sequatchie Valley, while to the northeast is degree of dissection, and impact of previous Grassy Cove, a large karst depression. glaciers. Two sections occur in Tennessee, Sandstone over shale is common, as are but neither were affected by glaciers. Instructor siltstones and clays with outcrops of limestone CUMBERLAND PLATEAU AND and shale in gorges plus sandstones on slopes. CUMBERLAND MOUNTAINS SECTION Coal beds are most prevalent northward and are a valuable resource, although surface mining (Containing four ecoregions) has devastated the landscape in some sites Extending from the Eastern Highland Rim on and contributed to acid runoff and reduced the west to the Valley and Ridge Province on the water quality. Soils have largely formed from east, the Cumberland Plateau and Cumberland weathering of underlying sandstones and shales GRAND DIVISION 3: EAST TENNESSEE GRAND DIVISION 3: EAST Mountain Section is 70 miles wide at the or from similar soils that have moved down northern end and 50 miles wide to the south. It slope (colluvial soils). Upland soils are shallow, covers 5,000 square miles in 22 counties. Much acidic, and low in natural fertility, while alluvial of the plateau tilts slightly to the west where material can contribute to a higher fertility in water is drained to theTennessee Big South Fork, Wolf, bottomlands and terraces. Obey, and Caney Fork Rivers. The Obed and Vegetation Characteristics Emory Riversof provide drainage to the southeast. The plateau remains largely rural and forested, General Description and Soil Characteristics although logging is prevalent. Urban areas are Numerous valleys, gorges, and ravines are scattered, and agricultural production is limited found on the western border where the Plateau to small fields except in the valleys and some meets the Eastern Rim. The eastern edge is the tablelands. Most farms are devoted to pasture, hay, small grains, vegetables, soybeans, and striking Waldens Ridge cliff (an escarpment), tobacco. which extends from Cumberland and Roane The classic work of Dr. Lucy Braun in the Counties to the Tennessee River gorge near the 1940s and 1950s classified the entire plateau Tennessee–Georgia–Alabama line. Elevations as part of the Mixed Mesophytic Forest of the Plateau average 2,000 feet with a high of Region, but recent work shows that much of 3,534 feet at Cross Mountain. Sandstone cliffs, the plateau is dominated by mixed oak forests, Universitysteep slopes, and waterfalls, such as Fall Creek including chestnut, post, black, scarlet, white, Falls in Van Buren County, are characteristic and blackjack oaks, often with Virginia, pitch, features. Sandstone rockhouses and natural and shortleaf pines, red maple, blackgum, and
2 - 22 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee Appalachian Mixed Mesophytic Forest One of the most prevalent and biologically diverse forest types in the eastern United States is the Appalachian Mixed Mesophytic Forest. Current examples stretch from southwestern Pennsylvania to northern Alabama, encompassing areas of eastern and middle Tennessee. These temperate forests, characterized by a mixture of trees adapted to cool, moist conditions, are biologically diverse, with beech, tulip poplar, sugar maple, white oak, black walnut, yellow buckeye, white basswood, and cucumber tree being the major species. There are still Copy examples of relatively undisturbed Appalachian Mixed Mesophytic Forest in Tennessee, including the Frozen Head and Big South Fork natural areas as well as Scott State Forest.
sourwood. Hickories (pignut, mockernut, and Alabama. In Tennessee, this province extends shagbark) are also present. diagonally about 150 miles across the state from Riparian forests (along waterways) are northeast to southwest, withInstructor the Cumberland dominated by red maple along with river birch, Plateau on the west and the Unaka Mountains sycamore, and giant cane. Forests that have been on the east. It covers about 9,000 square miles. repeatedly logged occur across the plateau and It is drained almost exclusively by the Holston, are dominated by red maple, commonly with French Broad, and Tennessee Rivers. In fact, the blackgum, American holly, and white oak. In Tennessee River begins in this province with the successional fields and on upper slopes that have confluence of the Holston and French Broad been heavily logged or clear cut, Virginia and rivers near Knoxville. shortleaf pine communities are common. Mixed mesophytic communities do occur General Description and Soil Characteristics but are limited to protected sites where beech, The general landscape is a rolling upland tulip poplar, northern red oak, sugar maple, characterized by parallel ridges and valleys. basswood, white ash, buckeye, and shagbark Clinch and Powell Ridges and Bays Mountain hickory are common. Evergreen communities,Tennessee (3,097 feet) are the most common ridges in chiefly on lower slopes of deep ravines and in the north where valleys average 1,000 feet. coves, are dominated by hemlockof and white pine Southward, valleys average 750 feet in elevation, with northern red and white oaks, tulip poplar, and the highest ridge is White Oak Mountain and sweet birch. Sparsely vegetated glades and (1,495 feet) between Chattanooga and barrens occur on sandstone outcrops and nearby Cleveland. thin soils, as well as sandbars of streams and Limestone, shale, siltstone, sandstone, chert, riparian areas. These small, nonforested areas and marble are common bedrock materials. contain complex grassland, herb–shrub, herb– lichen, and small tree–woodland communities. (The area is known for high-quality marble.) Springs and caves are numerous. Soils vary by underlying rock type and are generally shallower East Tennessee over shales and sandstones and deeper over Physiographic Province limestone. Upland soils are often leached, University2: The Valley and Ridge acidic, low in fertility, and commonly used for The Valley and Ridge Province is a narrow band lumber, pasture, and hay. Valley floors, stream 1,200 miles long running from New York to bottoms, and terraces are more agriculturally
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 23 In coves and protected northern and eastern slopes, mixed mesophytic forests including dominant beech, tulip poplar, and sugar maple with white and northern red oaks, yellow buckeye, magnolias, black walnut, and white basswood are common. Hemlock may be a component in deeper ravines, in draws, and along streams. Slowly drained soils of upland depressions include numerous oak species and typical wetland species such as sweetgum. Bottomlands, terraces, and riparian Copy areas along the Tennessee River were once widespread, but Tennessee Valley Authority (TVA) impoundments inundated most of them. Existing riparian habitats are dominated by sycamore, river birch, green ash, and willow. Giant cane is common but few canebrakes remain. Eastern red cedar is a prevalent species on abandoned farms and is an obvious tree along rights-of-way,Instructor fencerows, and in poorly managed pastures. Common associates are persimmon, red maple, sassafras, and tulip poplar. Glades and barrens occur on scattered dry sites where red cedar, along with little bluestem as the dominant perennial grass, usually occur with big bluestem and dropseed. Cedar–oak, cedar–pine, pine, and remnants of the largely extirpated white cedar forests occur on limestone and sandstone river bluffs. Scattered white pine communities dominate on more mesic sites, SOURCE: Carol Reese, University of Tennessee and plantations of white, shortleaf, and loblolly Post oak pines occur in the southern part of the province. (Quercus stellata) Tennessee productive and are used for production of row East Tennessee Physiographic crops, vegetables,of soybeans, and burley tobacco. Province 3: The Blue Ridge Vegetation Characteristics (Unaka Mountains) Early descriptive systems classified the forests The Appalachian Mountains are part of the as oak–chestnut, but American chestnut extensive Appalachian Highland complex that losses prior to 1940 led to a more correct later extends from northern New England into the Appalachian oak designation. (See Figure Southeast. They are remnants of a former, much 4.) The province is currently 50% forested. greater highland area. Many of the mountains White oak is dominant, accompanied by black, are less than half their original height. The Blue chestnut, northern red, scarlet, southern red, Ridge Province extends from Maryland to and post oaks; pignut, shagbark, and mockernut Georgia. In Tennessee, it includes mountains hickories; blackgum; and red maple. On drier adjoining the Valley and Ridge Province. This Universitysites, chestnut oak dominates, but white oak is western crest of the Blue Ridge is called the still a major component. Exposed sites contain Unakas from a Cherokee word meaning "white, Virginia, shortleaf, and pitch pines. hazy, fog-draped."
2 - 24 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee Little bluestem (Schizachyrium scoparium) and eastern red cedar (Juniperus virginiana) Copy
SOURCE: Carol Reese, University of Tennessee Instructor Sassafras (Sassafras albidum) SOURCE: Carol Reese, University of Tennessee
The Unakas, encompassing 2,600 square miles, extend across Tennessee and include the prominent Roan Highlands, Great Smoky, Chilhowee, and English Mountains, among others. Major rivers, including the Holston, French Broad, Pigeon, Little Tennessee, Hiwassee, Tellico, and Ocoee all eventually flow into the Tennessee River. The area is the home of the nation's most-visited park (the Great Smoky Mountains NationalTennessee Park), covering nearly a half-million acres, as well as the Cherokee National Forest.of The Tennessee portion of the Appalachian Trail crosses the state through the Unakas, and these mountains are known worldwide for their diverse flora and phytogeographical (plant geography) relationships with other regions of the world. General Description and Soil Characteristics In the Blue Ridge region, rugged terrain with steep and rocky slopes is traversed by clear, cool, rushing streams, and waterfalls abound. Fertile limestone valleys and coves encircled by Universitymountains, including Cades, Tuckaleechee, and Wear, are some of the best-known landscapes. Elevations generally range from 1,000 feet
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SOURCE:Instructor Natalie Bumgarner, University of Tennessee The Unaka Mountains
in valleys and coves to more than 6,000 feet. Clingmans Dome, the highest point in Tennessee, reaches 6,643 feet, and nearby Roan Mountain is 6,286 feet. A wide range of rock types are found in the province, and soils vary from those formed in place (residuum) to those formed from colluvium. (See Table 1.) Both of these soil types have a range of depth and stone percentages. TennesseeSoils are generally acidic and well drained, with upper ridges and slopes having loamy and rocky soils approximately 1 to 3 feet deep. Deeper of soils on slopes are often rocky but fertile and support high-quality woodlands. Limestone valleys and coves contain deep, productive soils and are often heavily populated if not in public Fraser’s sedge ownership. Cultivated land is minimal when (Cymophyllus fraserianus), compared to other regions, but crops include which is a rare livestock, pasture, hay, corn, truck crops, and perennial found burley tobacco. in the southern Appalachians. There Vegetation Characteristics are no other species In addition to the rugged terrain that provides in this genus widely varying environmental conditions, University elevation changes alter temperatures and precipitation in the Blue Ridge region. These SOURCE: Natalie Bumgarner, University of Tennessee diverse characteristics greatly affect the
2 - 26 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee composition of the forests. An early survey of The main chain of the Unakas lies east of the region reported that oaks comprised over the foothills. Based on studies in the Great 40% of the standing timber, while American Smoky Mountains, forests are generally chestnut accounted for 17%. Hemlock was the described either as those on slopes from 1,000 only other species, accounting for over 5%. to 4,200 feet in elevation or those above 4,200 Foothills of 1,000 to 4,000 feet, including feet. Below 4,200 feet, forests in sheltered coves, Chilhowee, English, and Iron Mountains, are ravines, and on north-facing slopes are occupied the westernmost features. Chilhowee Mountain by mixed mesophytic forests (also called cove is a well-studied example of forests recovering hardwoods), which is the most species-rich of from extensive logging (including clear cuts), our deciduous forests. Major dominants are cultivation on lower slopes, and fires. Major beech, white basswood, sugar maple, yellow Copy forest types are (1) chestnut oak–mixed oak, buckeye, tulip poplar, silverbell, and hemlock. especially on northern and eastern slopes, Common associates are white ash, northern red (2) oak–pine with chestnut and white oaks and white oaks, cucumber tree, black cherry, and pitch and Virginia pines on south and black walnut, bitternut and shagbark hickories, southwest slopes, (3) Virginia pine–pitch pine red maple, and (formerly) chestnut. Also in the on drier south and west slopes with scarlet or canopy are magnolias (umbrella, bigleaf, and chestnut oak as associates, and (4) oak–hickory Fraser’s), yellowwood, and serviceberry, with with chestnut and black oaks and pignut and magnolias plus mountain and striped maples in mockernut hickories on lower north slopes. the subcanopy. The shrub and herbaceous layers Other forest types include mesic sites in low- of these forests have the Instructorhighest species richness elevation coves, stream bottoms, and mountain of Tennessee’s forests. benches dominated by tulip poplar; hemlock– Eastern hemlock, the evergreen of the white pine type restricted to deep ravines and mixed mesophytic forests, occurs over a Hemlock (Tsuga canadensis)branch the base of steep slopes; and a Table Mountain wide range of sites and elevations. At upper showing healthy pine type in small areas near the crests of drier elevations, it is a dominant large tree on foliage without peaks. a number of sites. Moving downslope it indications of feeding by the woolly adelgid SOURCE: Natalie Bumgarner, University of Tennessee
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An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 27 becomes more confined to coves and riparian Above 4,200 feet elevation, communities habitats where its thick, evergreen canopy are less diverse and more acclimated to shorter contributes to the coolness of mountain streams. growing seasons, increased precipitation, and Unfortunately, this species is being eliminated lower average temperatures. With increasing from the Unakas by the exotic hemlock woolly elevations there is more snow, persisting fog, adelgid, an insect that could cause the extinction strong winds, some ice, and extreme cold. of the species throughout its range. Spruce, spruce-fir, and fir forests occupy the On drier and more exposed slopes are most area. found complex oak forests with dominant From about 4,200 to 4,900 feet, red spruce northern red oak on mesic sites and near the is the dominant species with a mixture of Copy altitude limit of the oaks. White oak is found deciduous mesophytes such as yellow buckeye, at lower elevations on mesic and submesic sweet birch, beech, and northern red oak. With sites, with chestnut oak on south- and west- increasing elevation, red spruce and Fraser fir facing leads and ridges. Important associates become codominants, and deciduous species are black, southern red, scarlet, post, and of yellow birch, serviceberry, and mountain ash blackjack oaks. On dry or disturbed sites, pines become fewer. also may be associates. American chestnut was Above 6,200 feet, Fraser fir becomes the sole once important in these oak forests. At lower dominant species. However, the fir and spruce– elevations, the driest and most exposed south- fir forests have undergone drastic changes in the and southwest-facing ridges are more open oak– last 30 years due to fir death from exotic balsam pine and pine forests. Virginia and shortleaf woolly adelgidInstructor damage. Red spruce dieback, pines occur at lower elevations, replaced by mortality, and reduced growth occurred with pitch pine upslope, and then mixed with Table death of fir and increased exposure to ozone An example of a bald in the Mountain pine at the upper limit of pines. and other air pollutants. These conditions can Appalachian White pine becomes more important in the be exacerbated by fog and wind, which carry mountains northeastern part of the province. the pollutants from lower elevations. Because of dominated by grasses SOURCE: Natalie Bumgarner, University of Tennessee
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2 - 28 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee these challenges, the current fir and spruce–fir Bluffs and eastward to the Tennessee River. ecosystems have virtually collapsed and decades This area forms the Coastal Plain with its slow- (at least) will be needed for these systems to flowing, meandering streams, swamp forests, recover. Reelfoot Lake, and broad agricultural fields. Beginning at about 4,200 feet and Cotton was once the major agricultural crop extending to 5,400 feet, with boulder fields of and is still important, although agriculture is surface rocks, the Unaka’s equivalent of northern now more diversified. Memphis is well known hardwood forests is found. These mostly for its medical centers, historical attractions, and deciduous forests are variously dominated by the unique culture, food, and music of the "Bluff beech, yellow buckeye, yellow birch, white City." basswood, sugar maple, and black cherry, often Middle Tennessee, physiographically Copy with hemlock, striped and mountain maples, a broad rim surrounding an eroded basin, is white ash, and red spruce. Beech extends the land of country music, walking horses, upslope into the spruce–fir forests in “beech large military installations, dark-fired tobacco, gaps” on south-facing concave areas between botanical nurseries, a former iron mining and spruce-covered ridge crests. smelting industry, Civil War legacy, and major Scattered at high elevations are small, medical and educational centers. Part of the nonforested sites called balds that are dominated infamous Trail of Tears plus the northern end of by species of the heath family (Ericaceae) and the Natchez Trace (now a National Parkway), grasses. Research indicates that most of these and Nashville, the state's capital, are found here. balds were probably created by post-settlement The Central Basin withInstructor its cedar glades and farmers for pasture. A typical heath bald several endemic plants, the Pennyroyal Plain to has a “canopy” of Catawba rhododendron the north with barrens and extensive grasslands and mountain laurel with a subcanopy of (mostly historical), and barrens and karst areas sand myrtle and a ground cover of galax and to the southeast make Middle Tennessee unique. trailing arbutus. These heath communities High and low dams resulting in impoundments are on south-facing, convex ridge crests and of portions of the Tennessee and Cumberland can be seen developing on exposed slides and Rivers and some of their tributaries provide avalanche scars maintained by soil conditions electricity, flood control, transportation, and and plant activities. Balds dominated by water-related recreation, mostly lacking prior to grasses, particularly mountain oat grass, the 1940s. are found on exposed, chiefly southwest- East Tennessee, the land of the Cherokee, facing slopes. At the lowest elevations, begins with the rugged and beautiful bottomlands, valleys, and valley-likeTennessee coves Cumberland Plateau, a land of rockhouses, were originally forested but many have been natural bridges, waterfalls, the striking eastern cleared for agricultural use and urban areas. escarpment, and tablelands with deep gorges of and ravines. The Big South Fork National SUMMARY Recreation Area is a national treasure. This is the Tennessee is a tremendously diverse state coal-mining region of the state, and the results in terms of its history, culture, agriculture, have been environmentally devastating in some physiography, and vegetation. This diversity places. is due in large part to the long east-to-west In the Valley and Ridge Province, we find dimension of the state that covers physiographic the origin of the "Tanase” (Tennessee) River, regions from coastal-like on the west to the the University of Tennessee’s “Vol Nation,” eastern high mountains. The three Grand and the metropolitan areas of Knoxville and Divisions reflect this diversity. Chattanooga. The rolling uplands, fertile valleys, West Tennessee, the land of the Chickasaw, and rivers provided ideal settlement areas for Universitybegins with the Mississippi River, extends across Native Americans and early Europeans, and they the alluvial plain with its extensive farms, and eventually became major battlegrounds during continues over the loess-covered Chickasaw the Civil War. Impoundments of several rivers
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 29 Copy
SOURCE: Natalie Bumgarner, University of Tennessee Instructor Taylor Hollow in Sumner County is one of the few are significant landscape features today, as in the the majority of the state's physiography is little remaining areas of case of Middle Tennessee. changed since settlement. The plant life has mesophytic forest The Unaka Mountains extend across the suffered, and many of today’s plant communities in middle Tennessee state and provide beauty that almost defies have been severely altered. Yet the awe-inspiring that has had minimal human impact. It is description. High mountains, peaceful valleys spring and summer green of forest canopies and home to a beautiful with agricultural settings, Roan Mountain their understories of wildflowers, followed in fall spring display of (especially when rhododendrons are in bloom), by the diversity of colors and then the starkness blue-eyed Mary (Collinsia verna) that the Great Smokies, the Appalachian Trail, of winter are still there to be observed. are indicative of old Clingmans Dome, and magnificent cove forests Most important, the forests, barrens and growth forest. with carpets of wildflowers are features unlike prairie remnants, wetlands, and glades have the any others in the state.Tennessee The strong, resilient ability to respond favorably to protection and people, mountain churches, Appalachian music, management, even after decades of misuse. This and numerous other features provide a link to is testimony to their inherent resilience and their our state's history.of continuing, renewable nature. Their collective So from Memphis to Mountain City, regrowth, reseeding, and renewal are attributes one can stand at almost any crossroads and that point to a favorable future for Tennessee’s appreciate the beauty and diversity of our plant life. Still, our help is needed, indeed state's physiography and plant life. Certainly, required, in stewarding our natural treasures. centuries of impacts associated with a growing The slogan “Keep Tennessee Green” is certainly human presence have altered the landscape, but still appropriate today.
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2 - 30 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee Common Names with Corresponding Latin Names A F American chestnut (Castanea dentata) Fraser fir Abies( fraseri) American elm (Ulmus americana) Fraser’s magnolia (Magnolia fraseri) American holly (Ilex opaca) American lotus (Nelumbo lutea) G galax (Galax urceolata) B giant cane (Arundinaria gigantea) bald cypress (Taxodium distichum) giant cut-grass (Zizaniopsis miliacea) Copy basswood (Tilia spp.) green ash (Fraxinus pennsylvanica) beech (Fagus grandifolia) big bluestem (Andropogon gerardii) H bigleaf magnolia (Magnolia macrophylla) hackberry ( ) bitternut hickory (Carya cordiformis) Celtis occidentalis hemlock ( ) black cherry (Prunus serotina) Tsuga canadensis hop hornbeam ( ) black oak (Quercus velutina) Ostrya virginiana black walnut (Juglans nigra) black willow (Salix nigra) I blackgum (Nyssa sylvatica) Indian grass (Sorghastrum nutans) blackjack oak (Quercus marilandica) bladderworts (Utricularia spp.) K Instructor blue ash (Fraxinus quadrangulata) kudzu (Pueraria montana) box elder (Acer negundo) buckeye (Aesculus spp.) L buttonbush (Cephalanthus occidentalis) little bluestem (Schizachyrium scoparium) C lizard’s-tail (Saururus cernuus) loblolly pine (Pinus taeda) cane (Arundinaria gigantea) Catawba rhododendron (Rhododendron catawbiense) M cattail (Typha latifolia) cedar (Juniperus virginiana) mallows (Hibiscus spp.) cherrybark oak (Quercus pagoda) mockernut hickory (Carya tomentosa) chestnut oak (Quercus montana) mountain ash (Sorbus americana) chinquapin oak (Quercus muehlenbergiiTennessee) mountain laurel (Kalmia latifolia) common broomsedge (Andropogon virginicus) mountain maple (Acer spicatum) coontail (Ceratophyllum demersum) mountain oat grass (Danthonia compresa) cottonwood (Populus deltoidesof) cow oak (Quercus michauxii) N cucumber tree (Magnolia acuminata) northern white cedar (Thuja occidentalis) D O dropseed (Sporobolus spp.) Osage orange (Maclura pomifera) E overcup oak (Quercus lyrata) eastern gama-grass (Tripsacum dactyloides) eastern red cedar (Juniperus virginiana) UniversityElliott’s broomsedge (Andropogon gyrans)
An Overview of the Physical Environment, Flora, and Vegetation of Tennessee 2 - 31 Common Names with Corresponding Latin Names (continued) P T panic grasses (Panicum spp.) Table Mountain pine (Pinus pungens) pecan (Carya illinoinensis) Tennessee coneflower Echinacea( tennesseensis) persimmon (Diospyros virginiana) Tennessee milk vetch (Astragalus tennesseensis) pickerelweed (Pontederia cordata) trailing arbutus (Epigaea repens) pignut hickory (Carya glabra) tulip poplar (Liriodendron tulipifera) pin oak (Quercus palustris) pitch pine (Pinus rigida) U pondweed (Potamogeton spp.) Copy umbrella magnolia (Magnolia tripetala) post oak (Quercus stellata) V R Virginia pine (Pinus virginiana) red buckeye (Aesculus pavia) red cedar (Juniperus virginiana) W red maple (Acer rubrum) red spruce (Picea rubens) water hickory (Carya aquatica) redbud (Cercis canadensis) water oak (Quercus nigra) river birch (Betula nigra) water tupelo (Nyssa aquatica) rushes (Juncus spp.) water-lily (Nymphaea odorata) water-shield (InstructorBrasenia schreberi) S water-willow (Justicia americana) white ash (Fraxinus americana) sassafras (Sassafras albidum) white basswood (Tilia americana) sand myrtle (Kalmia buxifolia) white oak (Quercus alba) sandbar willow (Salix exigua) white pine (Pinus strobus) scarlet oak (Quercus coccinea) willow (Salix nigra) scouring rush (Equisetum hyemale) willow oak (Quercus phellos) sedges (Carex spp.) winged elm (Ulmus alata) serviceberry (Amelanchier spp.) shagbark (Carya ovata) Y shellbark hickory (Carya laciniosa) shortleaf pine (Pinus echinata) yellow buckeye (Aesculus flava) Shumard oak (Quercus shumardii) yellow pond-lily (Nuphar advena) silver maple (Acer saccharinumTennessee) yellowwood (Cladrastis kentukea) silverbell (Halesia carolina) slippery elm (Ulmus rubra) smartweed (Polygonumof spp.) sourwood (Oxydendrum arboreum) southern red oak (Quercus falcata) spruce (Picea rubens) striped maple (Acer pensylvanicum) sugar maple (Acer saccharum) sugarberry (Celtis laevigata) swamp chestnut oak (Quercus michauxii) swamp cottonwood (Populus heterophylla) swamp privet (Forestiera acuminata) swamp white oak (Quercus bicolor) sweet birch (Betula lenta) Universitysweetgum ( Liquidambar styraciflua) switchgrass (Panicum virgatum) sycamore (Platanus occidentalis)
2 - 32 An Overview of the Physical Environment, Flora, and Vegetation of Tennessee