Mesic Hardwood Forest Ecological System

The Mesic Hardwood Forest Ecological System is widespread at Rock Creek Park, covering large areas of the rolling uplands and lower slopes of shallow and deep ravines. Its physical setting is characterized by conditions that are not extreme—not too wet, not too dry, not too steep.

Natural Communities in This Ecological System

Mesic Hardwood Forest Ecological System in Rock Creek Park

  • on mesic to dry, rolling slopes and ravines (common in park)
  • some tuliptree along with American beech or mesic-site oaks in the forest canopy
  • lower layers may have high species richness

Natural Community: Mesic Mixed Hardwood Forest

  • dominant community in park—just about everywhere except on the highest and driest, or steepest, or lowest and wettest parts of the landscape
  • canopy generally includes some mix of American beech with lesser amounts of tuliptree and white oak

Natural Community: Coastal Plain Oak Forest

  • on level to gently sloping terrain
  • on sandy soils in Coastal Plain
  • trees more typical of the Coastal Plain such as southern red oak, willow oak, and American holly

Natural Community: Basic Mesic Hardwood Forest

  • in deep, shaded, moist ravines, or on cool, groundwater-fed lower slopes
  • species-rich, with profusion of wildflowers and ferns

The soils in the Mesic Hardwood Forest Ecological System are not too coarse, not too shallow, and are fairly well-drained. Due to the lack of extremes, a wide diversity of plant species—both native and non-native—thrive in this ecological system.

Tip: to see ecological systems on the interactive map of Rock Creek Park, use Layers On/Off to switch the main data layer to Ecological Systems.

Images of This Ecological System

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Physical Setting

The physical setting of the Mesic Hardwood Forest Ecological System is a Goldilocks setting for plants—not too wet, not too dry, but just right. In Rock Creek Park, the Mesic Hardwood Forest Ecological System is found on gently to moderately sloping terrain, on concave lower slopes, and in ravines.

Soils are also unexceptional, ranging from fertile to rather strongly acidic, and from mesic (moist but not saturated) to somewhat dry (some becoming quite dry during droughts).

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Where to See It in Rock Creek Park

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Natural Processes That Maintain This System

Natural processes are responsible for maintaining the character of an ecological system.

Soil Formation

Soil formation is an important natural process in the Mesic Hardwood Forest Ecological System, which tends to have deeper and oftentimes more nutrient-rich soil than either the Dry Oak - Pine Forest Ecological System or the Hardwood Forest Ecological System. Read more about soils and soil formation in Ecology Basics|Physical Setting.

Canopy Gaps

Another important process is the creation of canopy gaps through natural disturbances. Since many kinds of trees require direct sunlight during part of their life cycle, sunlit canopy gaps scattered in the forest are important for perpetuating a mix of tree species. These small patches of sunlight in the forest are created when one or more natural disturbances such as wind, ice, insects, and diseases kill and/or topple mature trees.

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Ecological Threats to This System


Fire is infrequent to absent in the Mesic Hardwood Forest Ecological System. If fire does penetrate, it may have significant ecological effects. Both tuliptree and American beech have thin bark that does not protect them in forest fires. Many understory species common in this community are also susceptible to fire mortality. Forests in the Mesic Hardwood Forest Ecological System that have burned can completely lose their former character for decades or centuries. Early on in their recovery, they tend to be predominantly populated by successional canopy trees—trees such as tuliptree or loblolly pine in moister areas, and Virginia pine or sassafras in drier areas, depending on what seed sources are around. Ecobit: Forest Succession—Clues to the Past

Non-Native Invasive Plants

At Rock Creek Park, non-native invasive plants may be the biggest threat to the Mesic Hardwood Forest Ecological System. Here are some of the most common culprits:

Most non-native invasive plants get established along the edges of trails, roads, and recreational areas where the sunlight is best and foot traffic may have spread their seed. Many do just as well in shadier conditions, however, and creep their way into intact forests. Over time, non-native invasive plants can out-compete the native wildflowers, ferns, and shrubs for limited nutrients, sunlight, and water. This can result in a decrease in the abundance and diversity of native species—especially ones that require the most nutrients, including many delicate wildflowers. Read more about how non-native invasive plants outcompete native plants in Ecology Basics.

Over-Browsing by Deer

Another major threat to the Mesic Hardwood Forest Ecological System is an excess of white-tailed deer, which consume plants in the understory faster than many can recover. This could eventually wipe out the diverse field layer (including wildflowers) at Rock Creek Park as it has elsewhere in the region. Furthermore, deer's seeming avoidance of American beech seedlings could lead to the eventual dominance of that species in the canopy of this ecological system. Ecobit: Case Study: American Beech Mature American beech already currently dominates the canopy of some sites—possibly where oaks and chestnuts were preferentially logged in past centuries.

Other Threats

Historically, American chestnut was an important component of parts of the Mesic Hardwood Forest Ecological System—its absence is testimony to the devastating effects of non-native diseases. Ecobit: Chestnut Blight Today, several other non-native diseases and insects pose threats to some of the native plants of this system. White ash trees are seriously threatened by the emerald ash borer. Slippery elm could succumb to Dutch elm disease or elm yellows. Beech bark disease threatens American beech, and the viburnum leaf beetle threatens southern arrow-wood, blackhaw, and mapleleaf viburnum. Gypsy moth and sudden oak death are potential threats to oaks. The Asian long-horned beetle could threaten maples and elms.

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Range Beyond Rock Creek Park

A common ecological system of the Atlantic Coastal Plain, the Mesic Hardwood Forest Ecological System ranges from southern New Jersey south to Georgia. It typically occurs over hundreds of acres, occasionally interrupted by wetlands or other ecological systems.

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Abbreviated Name: Mesic Hardwood Forest (Southern Atlantic Coastal Plain)
Ecological System Code: CES203.242