The physical setting of Rock Creek Park brings together characteristics not typically found in one place. The park straddles the Fall Zone—the boundary between the Piedmont and the Coastal Plain. Its Mid-Atlantic climate combines aspects of southern climate with aspects of northern climate, and is influenced by both coastal and continental weather systems.
The diversity in Rock Creek Park's physical setting and the climate supports a diversity of plants and natural communities. Abiotic (non-living) factors—including climate, soils, geology, topography, and watersheds—work together to create different habitats that suit different plants. (Nor is it a one-sided relationship. Plants also affect the physical setting. See Natural Processes for more about the physical interactions among and between abiotic and living components.)
Interactions Among Different Aspects of Physical Setting
Although the subject of physical setting can be broken up into climate, soils, geology, topography, and watersheds, none of these factors exists independently of the others. Together they determine the shape and character of the landscape.
Soils, geology, and topography are especially tightly interwoven. For example, the underlying geology has a major influence on the topography (shape of the landscape), as well as on the chemistry and other properties of soils. In turn, the steep topography at Rock Creek Park creates opportunity for slope processes that transport sediment downslope and cause many hillsides to be blanketed with a thick layer of gravel (called colluvium) whose chemical properties are vastly different from the underlying bedrock.
Precipitation and wind—the agents of climate—also help sculpt the landscape, and the shape of the landscape creates microclimates. Deep, shady ravines at Rock Creek Park are a good example. Their relatively cool and moist microclimate favors species like American basswood, northern red oak, and wild hydrangea—plants that are more common at higher elevations or northern latitudes of the United States. (For more on microclimates, see Topography.)
The interaction of topography, climate, geology, soils, and water at Rock Creek Park leads to a wide spectrum of possible environments and habitats, which helps explain why the park contains such a diverse suite of plants and natural communities.
Explore these topics:
What is the growing season for plants in the vicinity of Rock Creek, and what extremes of weather are plant, animal, and human inhabitants likely to experience?
The ups and downs of the landscape at Rock Creek Park create more than visual interest; they create microclimates! Learn to read the landscape, and become familiar with Rock Creek Park's microclimates. What natural communities are associated with each?
Rock Creek Park covers only a small portion of the entire Rock Creek watershed where a half-million or more residents live. How is it related to the Chesapeake watershed?