Coastal Plain Oak Forest in Rock Creek Park

How to Recognize It

You’ll come across this natural community in the parts of Rock Creek Park that are in the Coastal Plain, usually in areas that were cleared during the Civil War era. Willow oak, southern red oak, and white oak form the canopy of the Coastal Plain Oak Forest, and vines (native and non-native) are common in the understory.
Listen to a podcast about this natural community.

• Natural Community: Coastal Plain Oak Forest

  
  

  If you trace the historic Civil War defenses circling Washington, D.C., you will find this forest east of Rock Creek.

  Credit / Author:

  Alison Shapiro

  Audio Transcript

  Through the brush, you spot a flash of gunfire. Across the horizon, enemies make their way toward your forts, bayonets swinging.

  During the Civil War, the Union army cleared the forests to build a ring of defensive forts around D.C. and to maintain open sight lines. But the Coastal Plain Oak Forest has since advanced, with tall oaks reclaiming their territory and vines growing up in a sneak attack of their own. Urban neighborhoods have also sprung up all around these former forts.

  On the flat to rolling terrain of this natural community, located east of the Rock Creek Valley, grow willow oaks (Quercus phellos), as well as southern red oak (Quercus falcata), white oak (Quercus alba), and pine trees (Pinus spp.). Native greenbriers (Smilax spp.) and poison ivy (Toxicodendron radicans) are also common here.

  Native birds like the red-bellied woodpecker can also be seen in these trees. You may spot the occasional red-shouldered hawk at the edge of the forest. This natural community is usually found near wetlands, but in this case is found near urban neighborhoods and on hillsides along the old Civil War forts of D.C.

  With such life and dense greenery, it can be easy to forget the war that reshaped this natural community long ago.

Identifying This Natural Community

Can you find this combination of key features?

• Mix of oak species, often including one or more of these: southern red oak (leaves with velvety, tan undersides), willow oak (leaves nearly pencil-thin), white oak (leaves with curvy outlines)
• (Optional) sweet gum and/or evergreen loblolly pine trees
• Vines (non-native and/or native) in the understory
• Near-absence of heath family shrubs and American beech trees
• Located on flat or rolling areas east of the core of Rock Creek Park

If so, welcome to Rock Creek Park’s Coastal Plain Oak Forest!

back to top

Seasonal Highlights

Spring Highlights

Plants & Landscape

Animals

• Pale green leaves emerging on vines (greenbrier), trees and shrubs
• Long clusters of tiny white flowers: black cherry (late spring)
• A pink or coral tinge to some oak leaves as they are just emerging
• Huge leaf buds of sweet gum
• An occasional white bouquet of flowering dogwood blooms
• Pairs of reddish winged seeds from red maple, twirling as they fall
• A thin layer of yellow pine pollen over everything during April
• Often loads of non-native invasive plants: Green knee-high garlic mustard*, vining lavender Chinese wisteria, and non-native viburnum shrubs flowering white
• Silky nests of eastern tent catepillars (often in cherry trees)
• Birds arguing over territory, building and sitting on nests; some young being hatched
• A flock of crows ranting at barred owl or red-tailed hawk—potential predators of nest young

Summer Highlights

Plants & Landscape

Animals

• Long clusters of tiny black berries on trees: black cherry
• Three-parted leaves of poison ivy growing as knee-high stems or climbing up trees, some forming green berries
• Young birds emerging from nests (early summer)

Autumn Highlights

Plants & Landscape

Animals

• Acorns and fallen oak leaves of various fascinating shapes and sizes
• Yellowing three-parted leaves of poison ivy falling to the ground in parts
• Birds eating pales berries of poison ivy or deep blue berries of greenbrier vines

Winter Highlights

Plants & Landscape

Animals

• Lingering clusters of deep blue berries on greenbrier vines
• Evergreen needle bundles of loblolly or Virginia pine
• Sharp-edged leaves of evergreen American holly, contrasted with female trees’ red berries—winter food for hungry birds
• Onion-shaped winter buds of the occasional flowering dogwood
• Thick hairy roots of poison ivy clinging to tree trunks

back to top

Where to See It

The Coastal Plain Oak Forest occurs only in the eastward Coastal Plain portion of Rock Creek Park where it may be found, among other places, at Barnard Hill, and at Fort Totten.

Area Occupied: 46.0 acres (18.6 hectares)

Map of Coastal Plain Oak Forest at Rock Creek Park.

NPS

back to top

Plants and Animals

• Plants

• Animals

Plants

Mature oaks and occasional pines populate the canopy of the Coastal Plain Oak Forest. Smaller native and non-native trees grow below that, and a riot of vines (mostly non-native or thorny or poisonous) and shrubs (mostly non-native) often grow tangled below that. Not much sunlight is left for the forest floor, which helps explain why the shade-loving non-native invasive garlic mustard is abundant there.

Two of the characteristic oaks, willow oak and southern red oak, are common oaks in Coastal Plain areas where the ground has been heavily disturbed. Mature Virginia pine (another clue to past soil disturbance) is finally aging out of some of these stands, but is still significant in others. In brief, the oldest vegetation here gives clues to this land's disturbed past.

Canopy Trees

The trees whose crowns intercept most of the sunlight in a forest stand. The uppermost layer of a forest.

• southern red oak
• Virginia pine
• white oak
• willow oak
• black locust (occasional)
• chestnut oak (occasional)
• loblolly pine (occasional)
• northern red oak (occasional)
• scarlet oak (occasional)

The canopy of this community consists mainly of oaks with occasional pines. The most common oaks here are southern red oak, willow oak, and white oak, with occasional other oaks, such as northern red, chestnut, and scarlet. Pine trees may include Virginia pine or loblolly pine.

Willow oak is more common in D.C.'s Coastal Plain than Piedmont, and helps set the Coastal Plain Oak Forest apart from other oak communities in Rock Creek Park's Piedmont. Southern red oak is also more common here than elsewhere in the park.

Understory Trees

Small trees and young specimens of large trees growing beneath the canopy trees. Also called the subcanopy.

• American holly
• black cherry
• blackgum
• elm
• red maple
• flowering dogwood (occasional)
• sweetgum (occasional)

Blackgum, red maple, black cherry, American holly, and elm can be found in the understory, along with an occasional flowering dogwood or sweetgum.

Sweetgum is more common in D.C.'s Coastal Plain than Piedmont, and helps set the Coastal Plain Oak Forest apart from other natural communities at Rock Creek Park.

Shrubs, Saplings, and Vines

Shrubs, juvenile trees and vines at the right height to give birds and others a perch up off the ground but below the trees.

• greenbriers
• eastern poison ivy
• blackberries (occasional)
• sassafras (occasional)
• white ash (occasional)

Vines are common here—greenbriers, eastern poison ivy, and non-native species—and so are non-native shrubs. You might also find native sassafras or white ash saplings, and blackberries.

Low Plants (Field Layer)

Plants growing low to the ground. This includes small shrubs and tree seedlings.

The field layer is sparse, and unfortunately, often composed of non-native invasive plants.

Non-Native Invasive Plant Species

A significant component of this community is the numerous non-native invasive species, from trees to low-growing plants!

Animals

The home range of the eastern gray squirrel averages 2 to 5 acres (1 to 2 hectares).

Matt Jones

Since these forest stands are generally small, and bordered by urban neighborhoods, animals that thrive here are the types that don't need vast stretches of good habitat to get by. The acorns are good wildlife food for small mammals like squirrels. Birds can feed on berries and seeds from vines, trees, and shrubs such as blackgum, red maple, black cherry, pine trees, American holly, eastern poison ivy, greenbriers, and flowering dogwood.

The Carolina chickadee is around all year.

Matt Jones

The Coastal Plain Oak Forest is a good place to see resident (non-migrating) birds such as the robin, cardinal, Carolina chickadee, tufted titmouse, Carolina wren, blue jay, white-breasted nuthatch, eastern towhee, song sparrow, mockingbird, mourning dove, or red-bellied woodpecker. Because of all the forest edges, expect to occasionally see red-shouldered hawks preying on squirrels or birds.















back to top

Physical Setting

Area Occupied: 46.0 acres (18.6 hectares)
Stand Size: Small to medium stands
Landscape Position: Sloping to nearly level terrain
Soils: Infertile, loamy, acidic soils
Geology: Coastal Plains sediments

The Coastal Plain Oak Forest is closely aligned with the location of sandy soils in the Coastal Plain region of the park. Sediments in the Coastal Plain were deposited by rivers and reworked by the ocean. Below the sediments lie metamorphic rocks similar to those in the Piedmont and Mountains. Much of the Coastal Plain terrain administered by Rock Creek Park (including the Fort Circle Parks east of Rock Creek) was cleared during the Civil War in the 1860s to build forts and maintain open sight lines for soldiers defending the nation’s capital. This oak forest has grown up since then in these disturbed areas.

Notable Variations

At Rock Creek Park, the Coastal Plain Oak Forest does not border wetlands, as would be typical for this natural community. Instead it’s surrounded by urban neighborhoods or occurs on hillsides along the circle of Civil War forts ringing D.C. It may be that the presence of the Coastal Plain Oak Forest in these places is a clue to the previous existence of wetlands nearby and/or an underlying clay layer that slows the drainage of water. Or perhaps a larger Coastal Plain Oak Forest once inhabited a more typical setting nearby, and these are remnants. At this point, these forested stands are not entirely understood.

Maybe, on the other hand, these oak forests in Rock Creek Park's Coastal Plain will prove to need a separate classification—a new name to set them apart from the Coastal Plain Oak Forest that truly does border wetlands. Not every acre of forested land in the Mid-Atlantic has been assessed. In the future there may be many more acres of similar forest found, with no adjacent wetlands. If there prove to be significant differences in function and form between these oak stands in the Fort Circle Parks and the true Coastal Plain Oak Forest, it may warrant a new name.

Lumping and Splitting

Lumping and Splitting

Natural communities change over time, as does the scientific understanding of those communities. Sometimes important distinctions are discovered within a natural community. When these distinctions are notable enough, two natural communities, rather than one, are then recognized. In such cases, a new name is added to the National Vegetation Classification (NVC).

In other cases, the opposite may be true: distinctions between two natural communities are discovered to be less important as more information is collected, and the two natural communities are lumped together under one name.

back to top

Natural Processes

Natural processes shape the land, create soil and topsoil, influence the water supply, and help determine the plants and animals that live in each natural community. Some natural processes act on large scales and affect more than one natural community at a time.

In This Community

Important natural processes in the Coastal Plain Oak Forest include

• soil formation
• canopy gap regeneration
• microclimate
• processes that create soils that are not too wet, not too dry

In the Broader Landscape

Some natural processes act on large scales and affect more than one natural community at a time. For example, in Rock Creek Park three natural communities are found in similar positions in the landscape. The Coastal Plain Oak Forest, the Mesic Mixed Hardwood Forest and the Basic Mesic Hardwood Forest all occur on rolling uplands and lower slopes of ravines, where they are protected from extreme weather conditions—such as the exposure to sun and wind at higher elevations, and flooding at lower elevations. Because of their landscape position, these communities share a similar microclimate.

In fact, these three natural communities are all part of a larger unit that ecologists refer to as the Mesic Hardwood Forest Ecological System. An ecological system is a group of several natural communities that share many of the same natural processes and aspects of physical setting. By extension, they may also share many of the same plant and animal species.

back to top

Ecological Threats

Each natural community faces ecological threats that could change its defining features, leading to its decline.

Non-Native Invasive Plants

The understory of the Coastal Plain Oak Forest in Rock Creek Park is full of non-native bushes and vines. The harms caused by non-native invasive plants include competition with natives for soil nutrients, sunlight, and pollinators, and degradation of animal habitat. (* indicates non-native)

• bush honeysuckles*
• non-native cherry species* (trees)
• Chinese wisteria* (vine)
• chocolate vine* (vine)
• common periwinkle*
• English ivy* (vine)
• garlic mustard* (low plant)
• Japanese honeysuckle* (vine)
• mulitflora rose* (bush)
• Norway maple* (tree)
• non-native viburnum species* (bushes)

Diseases, Pests, and Other Threats

Current and potential ecological threats for the Coastal Plain Oak Forest in Rock Creek Park include the following:

• Excessive deer browse: decimation of shrubs and oak seedlings and shrubs
• Gypsy moth: damage to oaks
• Sudden oak death (potential): damage to oaks
• Viburnum leaf beetle (potential): non-native invasive viburnums could harbor this pest which also attacks native viburnums in nearby communities
• Asian long-horned beetle (potential): damage to red maple and elms
• Dogwood anthracnose: decline of flowering dogwood

back to top

Making a Difference

The well-being of natural communities depends not only on land managers, but on all of us—neighbors, visitors, fellow inhabitants of Earth!

Park Management

Park staff monitor and protect natural communities in many ways to help deal with threats from non-native invasive plants and insects, diseases, and more.

Here are a few ways park staff are managing some of the ecological threats to the Coastal Plain Oak Forest:

• Excessive deer browse: deer management plan in place since 2012 using lethal and non-lethal means
• Gypsy moth: bacterial and viral insecticides, naturalized fungus, release of parasitic wasps
• Removal of non-native, invasive plant species: NPS staff, in collaboration with NPS partners and volunteers actively remove non-native invasive plants from previously selected areas, utilizing a variety of methods of removal.
• Potential arrival of diseases and invasive insects: Vigilance of park staff and visitors

Ecobit: An Extra Set of Eyes

An Extra Set of Eyes (Rock Creek Park)

Emerald ash borer (Agrilus planipennis) is a threat to Rock Creek Park's ash trees along streams and in mesic natural communities.
Leah Bauer, USDA FS Northern Research Station

It takes a village to keep natural communities healthy. Alert Rock Creek Park staff if you see any of the following along the trail:

• diseased vegetation
• infestations by non-native insect pests
• infestations by non-native plants
• dumped mattresses, tires, appliances and other environmentally damaging trash
• unauthorized trails
• homeless camps
• issues with stormwater runoff
• anything that looks amiss.

If you do see something you’d like to share, make a note of your location and jot down a description of what you see. If possible, take a picture. Contact Rock Creek Park's Chief of Resources Management at 202-895-6010.

For more about what to look for, explore the Plants and Animals section.

If you happen across a display of wildflowers or other beautiful scene, Park staff would probably enjoy hearing about that too!

You Can Help, Too!

If you are interested in helping to take care of the natural communities of Rock Creek Park, here are some ideas:

Volunteer

• Learn about volunteering at Rock Creek Park.
• Team up with Rock Creek Conservancy, a citizen-based, non-profit organization that hosts volunteer restoration events for the benefit of the lands and waters of Rock Creek. Contact: www.rockcreekconservancy.org, [phone], and [e-mail].
• Team up with Dumbarton Oaks Park Conservancy, another citizen-based, non-profit organization that hosts volunteer restoration events in partnership with the National Park Service to restore a 27-acre historic gem on one of Rock Creek’s tributaries in the nation’s capital.

In the Park

Trails:

Stay on trails and respect fences. Park staff sometimes put up fences to keep out deer or to discourage foot traffic in erosion-prone areas. You can help by staying out of fenced-in areas.

Pets:

Keep your pet on a leash so that it does not disturb animals or dig up plants. Clean up after your pet to help keep streams and rivers clean.

Keep Your Eyes Open:

Alert park staff if you see any of the following along the trail: diseased vegetation, infestation by non-native insects, invasion by non-native vegetation (especially Early Detection Rapid Response species), trash, unauthorized trails, or anything that looks amiss. Make a note of your location, take a picture if you can, and contact Rock Creek Park’s Chief of Resources Management at 202-895-6010.

At Home

Landscape with Natives:

Many non-native invasive plants started out as—or still are—popular landscaping plants, so you can help limit their spread by choosing native plants for your yard. If you do plant non-natives, remove seeds and berries before wind and animals spread them. English ivy won’t produce berries unless it’s climbing a vertical surface, so keep it off trees and walls.

Protect Streams:

Keep litter, fertilizer, pet waste, and yard waste off the streets where it can wash into the storm drains that lead directly to creeks. Consider installing a rain garden in your yard to slow down stormwater run-off and help recharge the groundwater.

back to top

Conservation Status and Classification

How vulnerable is a natural community to being eliminated? How similar or dissimilar is it to other natural communities? These questions are answered by naming and classifying natural communities, which helps us identify them and understand where each is found.

The U.S. National Vegetation Classification is the standard often used to classify natural communities.

Conservation Status

Conservation status indicates how vulnerable a natural community is. Conservation status can be measured globally and regionally.

Global Conservation Status: GNR – Not yet assessed
Subnational Conservation Status: D.C.: SNR – Not yet assessed

Classification

Official names reduce the confusion by providing a common language for talking about natural communities.

Abbreviated Common Name: Coastal Plain Oak Forest
Common Name: Mesic Oak Forest (Coastal Plain)
Scientific Name: Quercus falcata - Quercus michauxii / Ilex opaca Forest
Scientific Name Translated: Southern Red Oak - Swamp Chestnut Oak / American Holly Forest
Classification Code: CEGL006390
Associated Ecological System: Mesic Hardwood Forest Ecological System in Rock Creek Park

back to top