Plant Communities


Introduction
Up until this point, we have considered the human and physical aspects of the property.  The next layer to add to our understanding is plant communities - associations of plants often found together. 

In our region, nearly all areas will grow up into forest over time, so we will focus on forest types on this page.  The few exceptions to this truism are excessively wet, dry, steep, or high areas in which trees cannot grow.  At Wortroot, a few areas are maintained as open plant communities (fields) by artificial disturbance (mowing), one area remains unforested due to the steep and dry terrain, and a few other areas are open due to waterlogged soil.  All other parts of the property are forest communities. 


Factors Influencing Tree Composition of a Forest
There are many different types of forest communities in the eastern United States.  The type of forest community which can be found in a given area is influenced by many factors, which I will discuss briefly below. 

On the large scale, temperature and rainfall are probably the most important factors determining which trees will grow in a given area.  Our region has plant communities which could not survive during an extremely cold, extended winter but which also could not compete in a tropical climate.

On a smaller scale, soil moisture is perhaps the most important factor.  Hilltops and steep slopes tend to be dry, so only plants able to cope with drought can grow there.  In contrast, sheltered hillsides (particularly those which face north) and small valleys (often known as hollows or coves) host a variety of plants which appreciate wet conditions. 

Age of the forest also influences what trees will be found in a given area.  Over time, different trees will grow in the same forest.  A very young forest will consist of short-lived trees with wind- or bird-dispersed seeds which can sprout in direct sunlight.  Over time, slower-growing trees whose seeds sprout in the shade begin to take over the forest.  This change in forest composition over time is known as forest succession, the young forest is known as early successional, and the old forest is known as late successional.  Many scientists believe that, given enough time, a specific type of land area will always grow up with the same composition of tree species - known as the climax forest. 

Other factors are also important.  Geology and soil type influence what trees can grow in a certain area.  The disturbance history (grazing, logging, snowstorms, insect infestations, etc.) of an area also influence the health and composition of a forest. 


Introduction to the Communities List
The rest of this page is devoted to a description of each type of plant community found at Wortroot.  I have mentioned the rough location of each community type on the property, but have not included a map delineating the community boundaries since plant communities tend to intergrade at the edges. 

For each of Wortroot's communities, I have listed the dominant tree species as well as other typical plant and animal species found in the community.  As you will begin to notice, plant communities do not merely refer to a specific set of tree species, but instead refer to a conglomeration of plant and animal species typically found together. 

Identifying a plant community is more of an art than a science, requiring an understanding of which species are most typical of a given community.  No single species is diagnostic of a plant community, and every species listed as typical of a community is not found in every area.  You will also notice that some plant and animal species are generalists which are found in several different plant communities.

Finally, these community descriptions are merely a snapshot in time.  As the forest is allowed to age, the composition and extent of each community type will change. 

                    
Source
Kricher, J.C.  1988.  Ecology of Eastern Forests.  Houghton Mifflin Company, Boston. 


Cove Hardwood Forest

Location at Wortroot: A large percentage of the property is covered by cove hardwood forest.  Cove bottoms are all cove hardwood forest, but so are many of the slopes.  In particular, cove species can be found nearly up to the top of Middle Cave Ridge and Upper Cave Ridge.

Dominant Tree Species: No one tree species defines the cove hardwood forest.  This exclusively southern Appalachian plant community is defined instead by the many different kinds of trees found therein.  At Wortroot, cove hardwood forests often include Beech, Black Birch, Tulip-tree, Red Maple, Sugar Maple, Box-Elder, Sycamore, Black Walnut, Buckeye, White Ash, Cucumber-tree, Fraser's Magnolia, Basswood, White Pine, and a few scattered oaks and hickories. 

Other Plants:  The understory of a cove hardwood forest is typically made up of younger versions of the trees found in the canopy, with the addition of Spicebush, Pawpaw, Ironwood, Witch Hazel, Elm, Redbud, and Red Mulberry.  The forest floor is also very diverse, although more so in coves and near the bottoms of slopes than higher on the hills.  Herbaceous (non-woody) plants are represented by a great variety of species, many of which bloom in the early spring.  These early spring ephemerals form astonishing stands on the east side of Middle Cave Ridge.  Some of the more typical herb species found in cove hardwood forests at Wortroot are: Mandarin, Trout-Lily, Trillium, Bellwort, Crested Dwarf Iris, Spring-Beauty, Rue Anemone, Hepatica, Blue Cohosh, Twinleaf, Bloodroot, Celandine Poppy, Toothwort, Mitrewort, Foamflower, Wild Geranium, Jewelweed, Violets, Jacob's Ladder, Fern-leaf Phacelia, Blue-eyed Mary, Lousewort, Great Blue Lobelia, and Bigleaf Aster.
Trillium
A fading bloom on a Large-flowered Trillium.


Wildlife: Most of the animals which are used as indicators of cove hardwood forests require large expanses of mature forest.  Since the cove forest on the property is relatively young, many of these species cannot be found at Wortroot.  Of course, a great variety of species which can be found in neighboring plant communities are also found in cove hardwood forests and some of these (Carolina Chickadee, Tufted Titmouse, Carolina Wren, Pileated Woodpecker, Wild Turkey, Wood Thrush, Ovenbird) can be indicators of this community type.  As the forest ages, I would expect to see a greater diversity of salamanders and to see many more mature-forest birds (such as Hooded Warbler, Worm-eating Warbler, Louisiana Waterthrush, Summer Tanager, and Acadian Flycatcher) taking up residence in Wortroot's cove hardwood forests.  In terms of mammals, White-tailed Deer are already relatively common here, and if the forest were connected to a larger tract of forest it could be home to Black Bears. 

Age/Successional Stage: Land which is conducive to the growth of cove hardwood trees is also often the best land for farming and pasture.  As a result, most of the cove hardwood forest on the property is quite young.  Some portions of the forest, which were pasture only thirty years ago or even more recently, have not even grown up to a stage that is recognizable as cove hardwood forest.  These areas are described in the section on early successional forests.  Many of the older areas are on such steep hillsides that the forest has taken a good deal longer than expected to develop.  The entire property was logged in the past, definitely within the last hundred years and probably much more recently, so none of the forest has really reached its climax composition.


Mixed Oak Forest

Location at Wortroot: Oak forest at Wortroot is found at the very tops of Middle Cave Ridge, Upper Cave Ridge, and on the various spurs which run off these two ridges.  Typically, the hillsides of the ridges and spurs have a strong cove hardwood affinity, with cove species only absent from the very peak of each area. 

Dominant Tree Species: Field guides tend to refer to this forest type as "oak-hickory forest."  However, in our region, oaks (primarily Chestnut Oak and Northern Red Oak at Wortroot) are the dominant species with only a few hickories (primarily Shagbark Hickory) mixed in.  American Chestnut also used to be an important component of this forest type until it was wiped out by the chestnut blight; small sprouts and one large chestnut tree can still be found on the property in this forest type.  Other dominant trees found in the mixed oak forest include Beech, Red Maple, Shagbark Hickory, and Blackgum.  However, in all but the driest areas, a large number of cove species are mixed into the forest, especially Sugar Maple, Tulip-tree and White Ash.

Other Plants:  The understory tends to contain the same species found in the overstory, with the addition of Sassafras, Serviceberry, and Redbud.  In addition, residuals of a younger forest (including Wild Black Cherry and Elm) are sometimes mixed in.  The forest floor is much less well-endowed than in the cove hardwood forest.  Drought-tolerant species such as Naked-flowered Tick-trefoil and Spotted Wintergreen are often found here along with Violet Wood-Sorrel. 

Wildlife: Mixed oak forests host a diversity of wildlife which are attracted to the nuts (acorns, hickory nuts, and beech nuts.)  Squirrels, White-tailed Deer, Wild Turkeys, and Blue Jays are all commonly found here. 

Age/Successional Stage: The forest is relatively young, but includes a few large trees which were probably overlooked during the last round of logging.  Large trees can also be found along the property boundaries.  There are plenty of oaks which are old enough to drop acorns, an important food source for many animal species. 


Beech Forest

Location at Wortroot: Relatively mature forest areas on Beech Bluff.

Dominant Tree Species: This forest type does not really match any of the forest types described in the Peterson Field Guide.  Beeches are by far the most common trees, but the forest also has trees from both the mixed oak forest and the cove hardwood forest.  Common species include Red Maple, hickories, Sourwood, Tulip-tree, Sugar Maple, Red Oak, Sassafras, Umbrella Tree, White Ash, and an occasional Eastern Hemlock.  The large component of Beech is probably due to the relative maturity of the forest and to the underlying limestone geology.

Other Plants: The most common tree in the understory is Sugar Maple.  In addition, the species found in the canopy are well represented, along with elm, Flowering Dogwood, and Spicebush.  Near Solomon Cove, the shrub layer is dominated by Buffalo-Nut.  The herb community is less diverse than in the cove hardwood forest (but with some of the same species) and is more diverse than in the mixed oak community.  Beechdrops are very common. 

Wildlife: Common animals include squirrels and all of the typical forest birds. 

Age/Successional Stage: The forest is approximately contemporary in age to the mixed oak forest.


Early Successional Forest

Location at Wortroot:  Early successional forest at Wortroot is primarily found in the white areas on the map below.  The main areas are on the top of Beech Bluff and along the south side of Middle Cave Ridge.
Age of forest.

Dominant Tree Species: There are three different types of early successional forest at Wortroot.  All types can include Tulip-tree, Redbud, Flowering Dogwood, Wild Black Cherry, Persimmon, Sumac, Red Cedar, Virginia Pine, Pitch Pine, and a few species from the nearby mature forest.  The three types differ in the proportion of each species found in the forest.  Which type of forest will grow up in a given spot depends primarily on soil type and on land use history. 
Other Plants: Since the trees are young and small in early successional forest, a great deal of light is able to reach the forest floor.  Dense patches of Poison Ivy are common, while patches of Ground Pine can be found beneath the conifers.  Many old field species survive in these young forests, including grasses, brambles, and several invasives.  Only a few forest herbs can be found here. 

Wildlife: Some animals, such as Ruffed Grouse and White-tailed Deer, are most frequently seen in early successional forest.  Many other species will wander into the young forest from nearby, older forests in order to feed.  Field animals may go into young forests for shelter.  Many species, though, will not use early successional forest.  The young forest lacks standing dead trees (snags) which many birds and mammals use for nesting or denning.  The ground has not yet built up a dense enough layer of leaf litter to protect salamanders.  Many forest interior birds will not nest in these areas, or if they do will inevitably lose all of their eggs to nest predators such as Raccoons, Virginia Opossums, and Brown-headed Cowbirds.   

Age/Successional Stage:  The map shown above was produced in 1989, so the forest in these areas is 15 years old or younger.


Artificial Open Areas

Location at Wortroot:  Open areas at Wortroot are primarily made and maintained by man.  They include the hay field at the southwest end of the property, the new site field, the yard and garden around the house, and the meadow along Raccoon Branch. 

Plants: This community is dominated by grasses and short-lived (annual and biennial) herbs which do not require tree cover.  Many of the species are alien, including Fescue and Crown Vetch. 

Wildlife: Our region does not have many species which are found exclusively in open areas, and the open areas on the property are too small to provide habitat for the few which do live in our region.  Birds such as Eastern Meadowlarks, Field Sparrows, White-eyed Vireos, and American Kestrels occasionally visit the open areas on the property from nearby pastures.  Many more species can be found on the edges between woods and open areas.  These brambly areas are home to Indigo Buntings, Eastern Towhees, Northern Mockingbirds, and Brown Thrashers, among other bird species, and are often frequented by mammals such as Eastern Cottontails. 

Age/Successional Stage: The open areas found on the property are the first stage in succession.  If they were not maintained by mowing, they would grow up into early successional forest and then into one of the mature forest types found on the property. 

Management Note: Open areas can be quite diverse.  However, a great deal of the diversity consists of alien invasive species (such as European Starlings and Brown-headed Cowbirds) and open areas can act as pathways for the dispersal of these alien species.  At Wortroot, most of the open areas are at the edges of the property and do not seem to be assisting the spread of alien species into the interior. 


Natural Open Areas

A few natural, or semi-natural, open areas can also be found on the property.  Tree falls in the forest create gaps in the canopy, but these areas are usually too small to host open area species and are quickly taken over by forest species.  The pines which have been killed by the southern pine beetle have opened up a much larger gap which acts more like an artificial open area turning into forest. 

There is one open area on the property of ecological interest.  It is a small patch found on the southeast side of Middle Cave Ridge above the meadow.  This area was probably originally opened up by man for pasture, but may now be a self-perpetuating open area due to the steepness of the hillside.  More likely, the forest will grow back eventually as buildup of organic matter slowly exceeds the soil loss due to erosion.  In any case, the open area is currently acting like a barrens community, with a variety of small herbs as well as some Sumacs.  Of particular interest was the sighting of a couple of individuals of the rare Northern Metalmark butterfly in the barrens area. 


Wetlands

Location at Wortroot:  A variety of small wetlands can be found on the property.  These include the damp areas bordering creeks, small seep areas in the woods, and a small, open marsh near the new site.  In addition, two ponds have been built on the property. 

Plants: Seeps in the woods are usually dominated by Jewelweed.  Wetlands which are in the open house a variety of species such as cattails, rushes, and Northern Swamp Buttercup.  At the edges grow trees which enjoy having wet feet - sycamores, willows, etc.  

Wildlife: A few wetland birds visit the property, but the wetlands here are not extensive enough to provide them a permanent residence.  Great Blue Herons occasionally come to the ponds and creeks.  Canada Geese occasionally visit the ponds.  The ponds do provide important breeding territory for frogs and newts, though.  In addition, many animal species which live in other habitats visit the wetlands for food or water.  

Age/Successional Stage: Ponds will eventually fill with silt and become wetlands, but the other wet areas on the property should be self-perpetuating in their current state. 




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Last updated 9/04.