Vegetation Classification and Mapping at Johnstown Flood National Memorial

Perles, Stephanie; Podniesinski, Gregory; Zimmerman, Ephraim; Millinor, William; Sneddon, Lesley

Vegetation classification and mapping was conducted at Johnstown Flood National Memorial, creating a current digital geospatial vegetation database for the park. Seven vegetation associations, Red Maple – Black Cherry Successional Forest / Woodland, Eastern Hemlock – Northern Hardwood Forest, Conifer Plantation, Silky Willow Shrub Swamp, Old Field, Cattail Marsh, and Riverine Scour Vegetation, that occur within the park were identified and described in detail. These vegetation types reflect the land use history, ongoing management, and varied environmental settings of the park. The vegetation association that covers the largest area of the park is Old Field, with three subtypes, Herbaceous, Wet Meadow, and Hawthorn, represented in different sections of the park. Red Maple – Black Cherry Successional Forest / Woodland is the most common forest type in the park, although its vegetation structure and composition varies. Two small remnants of Eastern Hemlock – Northern Hardwood Forest occur on shallow north-facing slopes in the park. The Conifer Plantation areas are remnants from the pine stands planted in the lakebed in the middle of last century. The Cattail Marsh and Silky Willow Shrub Swamp are maintained by the railroad berm that influences the hydrology in the immediate area. The Riverine Scour Vegetation is located on bars, islands, and spits in the South Fork of the Little Conemaugh River and is influenced by water and ice scour from the river. The effects of land use history and past and current management on these vegetation associations are discussed. Such land uses and management include creation and removal of plantations, lakebed hydroseeding, management of woody plants and exotic plant species, and natural succession. The habitat value of these vegetation associations for birds, reptiles, amphibians, and mammals is also discussed. A map showing the locations of these vegetation associations in the park was created following the USGS/NPS Vegetation Mapping Program protocols (The Nature Conservancy and Environmental Systems Research Institute 1994a, b, c). These vegetation associations were crosswalked to the National Vegetation Classification System (NVCS) in order to provide a regional and global context for the park’s vegetation. A dichotomous field key was developed for these vegetation associations to assist with field recognition and classification. This project documents the vegetation associations of Johnstown Flood National Memorial based on 2003 aerial photography and 2004 field sampling, and completes one of 12 basic inventory data sets for the park.

Vegetation Classification and Mapping at Johnstown Flood National Memorial

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