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VEGETATION CLASSIFICATION
AND MAPPING
OF
HOPEWELL FURNACE NATIONAL HISTORIC SITE
Technical Report NPS/NER/NRTR--2005/012
Greg Podniesinski
Stephanie Perles
Lesley Sneddon1
Bill Millinor2
Pennsylvania Science Office
The Nature Conservancy
208 Airport Drive
Middletown, PA 17057
1NatureServe
11 Avenue de Lafayette, 5th Floor
Boston MA 02111
2 North Carolina
State University Center for Earth Observation
5112 Jordan Hall
Box 7106 Raleigh, NC 27695
March 2005 (revised October 2005)
U.S. Department of the Interior
National Park Service
Northeast Region
Philadelphia, Pennsylvania
________________________________
Executive Summary
The vegetation
of Hopewell Furnace National Historic Site was mapped during 2002 and
2003 as part of the U.S. Geological Survey (USGS) / National Park Service
(NPS) Vegetation Mapping Program. The goal of the mapping effort was
to produce an up-to-date digital geospatial vegetation database for
the park. New aerial photography was obtained for the park in spring
2002 by Kucera International and converted to a digital orthophoto mosaic
image by the North Carolina State University Center for Earth Observation
in early summer 2002. The Pennsylvania Science Office of The Nature
Conservancy (PSO/TNC) interpreted the photography and developed a digital
formation-level vegetation map. PSO/TNC sampled 35 vegetation classification
plots during the summer of 2003. Data analysis identified 12 natural
or semi-natural vegetation types. Vegetation analysis information was
used to reclassify formation-level polygons to develop an alliance-level
vegetation map. Accuracy assessment of the alliance-level map constituted
a complete census of natural and semi-natural vegetation polygons. Overall
accuracy, as measured by the Kappa Index, was 88.77% ± 8.16%
(90% C.I.). The majority of mapping errors were associated with Tulip
Poplar Forest and Modified Successional Forest. NatureServe provided
crosswalk information between park vegetation types and National Vegetation
Classification System (NVCS) alliance types as well as alliance descriptions.
The resulting vegetation mapping product represents current vegetation
types within the park and is consistent with the standards of the USGS/NPS
Vegetation Mapping Program.
Natural vegetation types that are relatively undisturbed were easily
crosswalked to the corresponding NVCS alliance. Disturbed vegetation
types, especially the modified successional forest, had no NVCS equivalent
and were noted as park-specific types. The Eastern Red Cedar Woodland
was crosswalked to the Eastern Red Cedar Forest Alliance as no NVCS
woodland alliance currently exists for a red cedar woodland. Anthropogenic
vegetation types were not crosswalked to the NVCS, with the exception
of managed grasslands, which were crosswalked to the Orchard Grass–Sheep-sorrel
Herbaceous Alliance.
The most common
vegetation types were the Dry Oak–Heath and Dry Oak–Mixed
Hardwood Forests which, combined, covered approximately 203 ha of the
park (approximately 56% of park). Of the upland forests, these two forest
types tended to be the most intact with respect to low invasive and
exotic species abundance. The least common natural vegetation types
included the Birch Rocky Slope Woodland (limited to a single [0.75 ha]
patch on a bouldery slope in the southwest corner of the park). Other
uncommon vegetation types included shrub wetlands (Buttonbush Wetland
and Highbush Blueberry–Meadowsweet Wetland). The single occurrence
of the Buttonbush Wetland is within the active pasture and is very degraded.
None of the vegetation types described at Hopewell Furnace NHS are rare
in Pennsylvania.
Natural vegetation quality within the park ranged from fair (dry oak
forests) to poor (Buttonbush Wetland, some Red Maple Palustrine Forest),
reflecting the relative ease with which invasive species can colonize
wet and mesic soils. In addition, all portions of the park, especially
forests of all types, appear to have heavy deer browse damage visible
on tree regeneration and shrubs.
___________________________
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Appendix F:
Photos of vegetation classification sampling plots with index to photos
photos 1-6
photos 7-16
photos17-26
photos 27-36