VEGETATION CLASSIFICATION AND MAPPING
AT
PETERSBURG NATIONAL BATTLEFIELD,
VIRGINIA

Technical Report NPS/NER/NRTR—2008/127

Karen D. Patterson

Virginia Department of Conservation and Recreation
Division of Natural Heritage
217 Governor Street, 3rd Floor
Richmond, VA 23219

June 2008

U.S. Department of the Interior
National Park Service
Northeast Region
Philadelphia, Pennsylvania
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Summary

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 at the seven national parks in Virginia.

This report documents the classification and mapping of vegetation at Petersburg National Battlefield. Twenty map classes representing 13 USNVC associations, five nonstandard, park-specific vegetation classes, and three Anderson Level II land-use categories were used to map the 1,092 ha (2,698 ac) park. Vegetation map classes were determined through extensive field reconnaissance, data collection, and analysis. Aerial photography from February 2002 served as the base map, and field sampling was conducted from 2002–2006. Spatial data was digitized onscreen over digital orthophoto mosaics created from scanned color infrared, stereo pair 1:6,000 scale aerial photography using a 0.5 hectare minimum mapping unit.

Early successional or transitional vegetation covers 60% of the land in the park (654 ha [1,616 ac]). Cultural map classes cover almost 16% (170 ha [420 ac]) of the park and include the Anderson land-use categories and other man-made or maintained areas in the park. Six map classes representing later successional vegetation cover just over 24% of the land in the park (268 ha [662 ac]). These six map classes can be broadly characterized based on different environmental settings as upland forests and forested wetlands (three map classes each).

A vegetation map of Petersburg National Battlefield was created following the USGS-NPS Vegetation Mapping Program protocols. When possible, vegetation map classes were crosswalked to the Natural Communities of Virginia and the USNVC in order to provide a regional and global context for the park’s vegetation. Ninety-eight randomly selected accuracy assessment sampling points were collected throughout the park and used to assess the thematic accuracy of the map. The Kappa Index for the final vegetation map was 82.9±9%, with an overall accuracy of 85.7%.

A field key to the map classes, and detailed descriptions for map classes or 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, a database of vegetation plot data and accuracy assessment data, digital photos of vegetation associations, and spatial data files for the vegetation map, plot sample points, and accuracy assessment sample points with associated Federal Geographic Data Committee (FGDC)-compliant metadata.

Products for Petersburg National Battlefield and similar national park vegetation mapping projects can be accessed at the USGS-NPS Vegetation Mapping Program website:
http://biology.usgs.gov/npsveg/.

Keywords: vegetation association, vegetation classification, vegetation mapping, Petersburg National Battlefield.

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The Body of the Report

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Appendix A through Appendix I: Successional Tuliptree Forest

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Appendix I: Acidic Oak-Hickory Forest