Vegetation Classification and Mapping Project Report - USGS

USGS-NPS Vegetation Mapping Program
Colonial National Historical Park
Vegetation Classification and Characterization
Discussion
A comprehensive regional analysis resulted in the classification of over 100 USNVC
associations, spanning nearly all major physiographic provinces in the region. Thirty-five of the
associations are represented in the seven national parks included in this study. An additional 19
associations and 12 nonstandard, park-specific classes representing disturbed, cultural, or exotic
vegetation were also recognized from the seven parks. This study at Colonial National Historical
Park identified and characterized 40 map classes, representing 31 USNVC associations, seven
Anderson Level II land-use classes (Anderson et al. 1976), and seven nonstandard, park-specific
vegetation classes (Table 11). The diversity seen in the vegetation map reflects the varied
environmental settings of Colonial National Historical Park, as well as the park’s location in the
midst a rapidly developing urban/suburban area, and its mandate to preserve historic and cultural
features.
Transitional vegetation and cultural map classes cover 56.7% of the land in Colonial National
Historical Park. Transitional vegetation alone covers 37.4% of the land in the park (1308.4 ha
[3233.0 ac]). This vegetation is the result of relatively recent (20-80 years) abandonment of pine
plantations and fields, or tree canopy removal by disturbances such as pine bark beetle
infestation, wind, beaver activity, and timber harvests or other silvicultural practices.
Transitional uplands are dominated by early successional, weedy tree species in the canopy and
subcanopy, and can have high cover of nonnative plants in the shrub and herbaceous layers.
Transitional vegetation is also found fringing roadways and parking areas where upland and
wetland vegetation has been disturbed or fragmented by road construction. Beaver-disturbed
areas, or areas artificially impounded, typically occur as semipermanently flooded habitats
variously dominated by trees, shrubs, herbs, or open water. Where roads or berms have altered
the natural tidal flooding regime of formerly tidal vegetation, disturbed wetlands exist that are
transitional between oligohaline and freshwater systems. Each of these map classes are rapidly
changing in species composition and vegetation structure. In the absence of beaver and
nonnative plant species invasions, some of these stands would eventually succeed into one of the
later successional forest types mapped in the park. Map classes representing transitional
vegetation include: Disturbed Calcareous Forest, Disturbed Depressional Wetland, Disturbed
Seepage Swamp, Disturbed Tidal Hardwood Swamp, Semipermanent Impoundment,
Successional Black Walnut Forest, Successional Mixed Scrub, Successional Sweetgum Forest,
Successional Tree-of-Heaven Forest, and Successional Tuliptree - Loblolly Pine Forest. These
map classes are described in Appendix I.
Cultural map classes cover 19.3% of the park’s acreage (676.6 ha [1671.9 ac]). Cultural map
classes include Anderson land-use classes as well as vegetation resulting from planting or active
cultivation. Cultural Meadow is the most common cultural map class in the park, covering 363.0
ha (897.0 ac). Cultural Meadow includes all mowed or maintained fields and agricultural leases
in the park, as well as mowed roadsides over 0.5 ha in size. Most of the Cultural Meadow areas
are managed to keep an open landscape similar to the open farmland conditions found during the
18th century. Other cultural map classes include Dense Hardwood Regeneration, Golden
Bamboo Shrubland, Loblolly Pine Plantation, Industrial and Commercial Complexes, Mixed
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