Vegetation Classification and Mapping at George Washington Birthplace National Monument, Virginia

Patterson, Karen

Accurate and up-to-date vegetation maps are recognized by the National Park Service (NPS) Inventory and Monitoring Program as one of twelve basic data sets for every national park with significant natural resources. The National Park Service (NPS) and the U.S. Geological Survey (USGS) have put forth standards and protocols for classification and mapping of vegetation communities on NPS lands. The USGS-NPS Vegetation Mapping Program recognizes the United States National Vegetation Classification (USNVC) as the standard vegetation classification to be used in these mapping projects. Vegetation data collected from seven national parks in Virginia were combined with over 2,000 existing plot samples from throughout the Mid-Atlantic Piedmont and Coastal Plain and used to refine the USNVC for the mid-Atlantic region. This classification was used to map and describe the vegetation in those seven national parks. This report documents the classification and mapping of vegetation and other land-use classes at George Washington Birthplace National Monument. Nineteen map classes representing 16 USNVC associations, two nonstandard park-specific vegetation classes, and four Anderson Level II land-use categories were used to map the 223 ha (551 ac) park. Vegetation map classes were determined through extensive field reconnaissance, data collection, and analysis. The map was based on 2002 aerial photography and field sampling conducted in 2002 and 2003. Spatial data were digitized onscreen over digital orthophoto mosaics created from scanned color infrared, stereo pair 1:6,000 scale aerial photography using a 0.5 ha minimum mapping unit. Four cultural map classes cover 49% (113 ha [279 ac]) of the park: Cultural Meadow; Other Urban or Built-Up Land; Transportation, Communications, and Utilities; and Semipermanent Impoundment. Early successional or transitional vegetation covers approximately 19% (44 ha [109 ac]) of park land: Loblolly Pine Plantation / Early-Successional Loblolly Pine Forest, Disturbed Calcareous Forest, Disturbed Acidic Slope Forest, Successional Red-cedar Forest, Successional Sweetgum Forest, and Successional Black Locust Forest. Tidal wetlands account for approximately 7% (16.5 ha [40.7 ac]) of the park: Beaches, Tidal Oligohaline Marsh, Tidal Mesohaline and Polyhaline Marsh (Low Salt Marsh), and Tidal Shrub Swamp (Iva Type). Nontidal forested wetlands cover just 3% (7.5 ha [18.5 ac]) of the park land: Coastal Plain / Piedmont Acidic Seepage Swamp and Non-Riverine Saturated Forest. The remaining 16% (35.8 ha [88.5 ac]) of the park land is mapped as later successional forests: Coastal Plain Dry Calcareous Forest and Loblolly Pine - Hardwood Forest. A vegetation map of George Washington Birthplace National Monument was created following the USGS-NPS Vegetation Mapping Program protocols. Vegetation map classes were crosswalked to the Natural Communities of Virginia and to the USNVC in order to provide a regional and global context for the park’s vegetation. A field key to the map classes and detailed descriptions for map classes or vegetation associations within a map class were developed to assist with field recognition and classification. Additional products associated with this project include: leaf-on and leaf-off orthophoto mosaics, database of vegetation plot data, digital photos of vegetation associations, and spatial data files for the vegetation map and plot sample points with associated Federal Geographic Data Committee (FGDC)-compliant metadata.

Vegetation Classification and Mapping at George Washington Birthplace National Monument, Virginia

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