Field data for the Vegetation Mapping Inventory Project of Friendship Hill National Historic Site

This reference is an assemblage of field data collected as part the baseline vegetation inventory for the park unit. Typical files here are vegetation plot data, accuracy assessment data, field photos, PDF showing locations of vegetation plots and accuracy assessment data, and other data for this type. All vegetation plot sampling followed the USGS/NPS Vegetation Mapping Program protocols (The Nature Conservancy and Environmental Systems Research Institute 1994b). The protocol recommends that each vegetation association should have been sampled at least three times in order to capture the naturally occurring variation within the park. If each of the formation-level vegetation types listed in Table 2 represented only one association in Friendship Hill National Historic Site, the minimum number of plots needed would have been 25. This assumed that areas labeled with modified Anderson level II categories would not be sampled, and that for formations with less than three polygons, only one plot would be placed in each polygon. However, it is more likely that some formations represent multiple associations. Alternatively, a few of the formation-level vegetation types assigned to the map may actually represent a single association. This occurs because of significant variation in vegetation structure and leaf phenology caused by past land use, natural resource management, and environmental setting. This is contrary to the hierarchical nature of the NVCS, and illustrates why the formation-level map does not accurately reflect each polygon’s NVCS formation. Regardless, the formation-level map is a useful guide to determine the intensity, distribution, and location of vegetation sampling. Based on the formation-level map, our initial reconnaissance of Friendship Hill National Historic Site, and previous vegetation mapping efforts at this and other parks, we concluded that approximately 30 plots would be sufficient to capture the range of vegetation types. Polygons labeled Conical-crowned temperate evergreen forest were not sampled because they represented extremely small remnants of conifer plantations, a vegetation type adequately sampled at other nearby parks. Many of the Medium-tall sod temperate or subpolar grassland polygons were also excluded from sampling because they represented frequently mowed grasslands in which the plants could not be identified.

Field data for the Vegetation Mapping Inventory Project of Friendship Hill National Historic Site

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