Chris Lea, National Park Service, Natural Resource Information Division, Vegetation Mapping Program, Denver, CO Lesley Sneddon, NatureServe USGS/CSS/Core Science Analytics and Synthesis 20110931 vector digital data http://www1.usgs.gov/vip/thst/thstgeodata.zip doi:10.5066/F7NP22FT Field point features represent locations of vegetation classification sampling plots used to develop an association-level vegetation classification of Thomas Stone National Historic Site. From July 16-20, 2001, National Park Service staff collected vegetation and other environmental data at 23 plots. On August 1, 2001, data were collected from three additional plots, making a total of 26 plots. Plots were subjectively placed to be most representative of the stand. The position of the center of each plot was recorded by a GPS in Universal Transverse Mercator (UTM) Zone 18 North, North American Datum 1983 (NAD83), meters. Observation point features represent locations of "rapid assessment" observation points from which vegetation data were collected in May 2001. The position of each observation point was recorded using a Trimble Pro XR Global Positioning System (GPS). Accuracy Assessment point features in this dataset represent the center point of field plots where data were collected to assess thematic accuracy of the map of vegetation associations at Thomas Stone National Historic Site. In total, data were collected from 133 accuracy assessment sampling plots. Most points were visited during the week of October 6-10, 2003. On November 7, 2003 points in cultural (managed) vegetation, the map class representing storm residue (blowdowns from the 2002 tornado), and remaining natural vegetation were sampled. Following analysis of the results, it was determined that several situations contributed to high error rates between some similar classes. The observers had not had adequate practice with the key or the concepts in the descriptions, nor had the key itself been tested on observers in representative vegetation in order to correct key errors. As a result, it was decided to treat the initial accuracy assessment effort as a map validation to improve the classification, the map, and the key. Modifications were made to the classification scheme, the descriptions, and key for most of the map classes/associations representing natural vegetation. Because these modifications were made from information gained by the validation, a subsequent, independent accuracy assessment was conducted in June 2004 for each map class/association that was modified. Accuracy assessment data collected in 2003 for classes/associations not modified were retained. Plot data were collected to derive the vegetation classification. The purposes of this initial systematic assessment were to: (1) observe a large number of vegetation stands representing the full range of vegetation diversity, (2) collect limited quantitative (tree species composition) and qualitative (dominant or characteristic species) information to allow preliminary grouping of vegetation types into broad classes to maximize the efficiency of more intensive plot sampling, and (3) increase the number of spatially referenced training points for interpretation of remote sensing images. These data were collected to assess the thematic accuracy of the USNVC association level map developed for Thomas Stone National Historic Site 20010716 20040606 ground condition Complete None planned Thomas Stone National Historic Site and environs -77.044808 -77.029939 38.536523 38.521690 National Park Service Theme Category Thesaurus Vegetation plot Observation point thematic accuracy assessment ISO 19115 Topic Category Biology biota none Vegetation classification Vegetation mapping Wetlands National Park System Unit Name Thesaurus Thomas Stone National Historic Site National Park System Unit Code Thesaurus THST none Port Tobacco, Maryland Charles County, Maryland None Standardized National Vegetation Classification System vegetation classification alliance community association Kingdom Plantae none none Dennis Skidds National Park Service Data Manager mailing and physical address

Northeast Coastal & Barrier Network

National Park Service

University of Rhode Island

Rm. 105, 1 Greenhouse Rd.

Kingston RI 02881 USA 401-874-4305 Dennis_Skidds@nps.gov http://www1.usgs.gov/vip/thst/thstplots.pdf Locations of vegetation plots; low resolution for web browsing. PDF http://www1.usgs.gov/vip/thst/thstaa.pdf Locations of thematic accuracy assessment sites; low resolution for web browsing. PDF Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3000 Chris Lea, National Park Service, Natural Resource Information Division, Vegetation Mapping Program, Denver,CO; Lesley A. Sneddon, NatureServe, Boston, MA; Elizabeth Eastman, North Carolina State University, Raleigh, NC 201102 Technical Report NPS/NER/NRTR Philadelphia, PA U.S. Department of the Interior, National Park Service, Northeast Region ESRI point geometry Each vegetation plot, observation point and accuracy assessment point is represented by one point in the geodatabase. During July 16-20, 2001, seven National Park Service staff collected vegetation and other environmental data at 23 plots in both representative stands based on TWINSPAN analysis of observation point data, and in small-patch vegetation types identified in the field as likely representing distinct types. On August 1, 2001, data were collected from three additional plots, making a total of 26 plots. Plots were subjectively placed to be most representative of the stand. Most plots were 400 m2 in area, with the default dimensions for plots set at 16 m x 25 m. Field crews visually assigned the vegetation in each plot to strata (tree canopy, tree subcanopy, tall shrub, short shrub, herbaceous), and recorded all the vascular plant species of each stratum. The abundance of each species in each stratum in each plot was recorded as belonging to one of nine cover classes. In addition to floristic data, the following environmental information was recorded on field forms: soil profile description, flooding regime, soil moisture regime, soil texture, slope, aspect, and evidence of disturbance. A topographic cross-section profile was sketched by hand to represent the location and setting of the plot. Three soil samples were taken from subjectively chosen representative locations within the plot by inserting a 1.905 cm (3/4 in) diameter soil probe at least 25 centimeters (when possible) beneath the soil surface to extract the sample. A soil profile depicting changes in soil color and composition with depth was sketched for each 25 cm deep soil sample. The position of the center of each plot was visually estimated and recorded by a GPS in Universal Transverse Mercator (UTM) Zone 18 North, North American Datum 1983 (NAD83), meters. Plot data were entered into the USGS/NPS VMP PLOTS 2.0 database (http://biology.usgs.gov/npsveg/links.html). A second analysis was conducted in 2007 in which the vegetation plots from Thomas Stone National Historic Park were added to a larger data set analyzed for the vegetation classification of the National Park Service's National Capital Region. This analysis, conducted by Virginia Natural Heritage Program, included plots from all eleven National Capital Region parks, as well as other plot data previously collected in the vicinity by the natural heritage programs in Virginia, West Virginia, and Maryland. Once the classification was finalized, the resulting units were subjectively compared to existing USNVC associations. All of the units were assigned to an existing association. Unknown In late May 2001, the principal investigator made a two-day site visit to conduct a "rapid assessment" of the park vegetation. At each observation point, the investigator rotated in a full circle and counted the number of trees of each species filling the basal area factor 5 opening of a Jim-Gem Cruz-All timber cruising tool. Such a count yields an estimate of the basal area of each species in square feet per 0.2 acre. Each count was multiplied by 5 to yield an estimated basal area in square feet / acre (=0.2296 m2 / ha) for each species at each observation point. Notes were made on dominant and/or characteristic understory species. The position of each observation point was recorded using a Trimble Pro XR Global Positioning System (GPS). The observation point data collected during the rapid assessment were entered into a Microsoft Excel spreadsheet and converted to a format suitable for analysis using PC-ORD v. 3.04. The initial units derived from analysis of the observation point data were used in three ways: a) to identify all USNVC associations likely to occur at a potential sampling site; b) to identify vegetation stands that would maximize efficiency of plot data collection; and c) for supplemental information to more fully describe the respective associations. Unknown A dichotomous key to the vegetation associations was developed, and, with the local descriptions of associations, was provided to researchers conducting the accuracy assessment. Accuracy assessment was conducted during the week of October 6-10, 2003, when most of the points were visited. On November 7, 2003, points in cultural (managed) vegetation, the map class representing storm residue (blowdowns from the 2002 tornado), and remaining natural vegetation were sampled. Following analysis of the results, it was determined that several situations contributed to high error rates between some similar classes. The observers had not had adequate practice with the key or the concepts in the descriptions, nor had the key itself been tested on observers in representative vegetation in order to correct key errors. As a result, it was decided to treat the initial accuracy assessment effort as a map validation to improve the classification, the map, and the key. Modifications were made to the classification scheme, the descriptions, and key for most of the map classes/associations representing natural vegetation. Because these modifications were made from information gained by the validation, a subsequent, independent accuracy assessment was conducted in June 2004 for each map class/association that was modified. Accuracy assessment data collected in 2003 for classes/associations not modified were retained. Accuracy assessment largely followed the protocols of the USGS/NPS VMP (Environmental Systems Research Institute and The Nature Conservancy 1994). Deviations of this protocol are as follows: Because of the small size of Thomas Stone National Historic Site, the total number of polygons in the map is small, with no map class having more than 7 polygons inside the park boundaries, and the maximum area included in any single map class about 35 hectares. The USGS/NPS VMP protocols would recognize two map classes at Thomas Stone National Historic Site as rare, and all others as very rare, and would recommend 43 accuracy assessment points for the entire park and a maximum of 5 accuracy assessment points for any map class. While 43 points would produce narrow enough confidence intervals to give a reasonable assessment of the overall accuracy for the project, stratifying by map class according to the protocols would not have been fruitful, since no map classes would have sample confidence intervals narrow enough to be meaningful. However, we chose to exceed the number of accuracy assessment points recommended by USGS/NPS VMP protocols, since the points can still be considered independent observations. As a result, we weighted accuracy assessment points proportionally by area of map class occupied. The maximum number of accuracy assessment points (up to 30) that could be accommodated by the configuration of vegetation polygons within a map class without spatial overlap was selected for each class. This alternative design may be useful for assessing thematic accuracy at other small parks. Photointerpretation was conducted at a relatively high spatial resolution at Thomas Stone National Historic Site, For this reason, the accuracy assessment was conducted at the scale of a 0.25 hectare minimal mapping unit, rather than the 0.5 hectare minimal mapping unit assumed by the USGS/NPS VMP protocols. This mapping unit size is delineated on the ground by a circular observation plot with a radius of 28.2 meters around an accuracy assessment sample point. Using ESRI ArcMapTM 8.3, a 60 meter grid, with an origin established by a randomly selected x (easting) and y (northing) coordinate, was placed over the mapped polygons within park boundaries). Each point on the grid represented a potential accuracy assessment point to serve as the center of a circular observation plot (sample unit). Points that were within 20 meters of a polygon boundary were excluded from the population of sample points in order to eliminate possible confounding of causes of error (i.e., ground positioning error using a global positioning system (GPS)). For each map class/association for which 30 or fewer points were available within polygons in that class, all points falling within polygons representing that map class were selected as accuracy assessment points. For map classes/association that could accommodate more than 30 points, individual points were selected randomly and sequentially until a sample of 30 points was achieved. In three forested polygons, the delineated map unit was smaller than the minimum mapping unit. Each stand was visited during plot data collection, and was mapped in the field using a GPS. In these cases, a single accuracy assessment point was located in each polygon at the polygon centroid. Since each of these polygons had been thoroughly mapped and assessed on the ground, any errors in these classes could be assumed to be from interpretation of the vegetation key and descriptions, rather than from photointerpretion error. A total of 133 accuracy assessment sampling points were selected for Thomas Stone National Historic Site. The coordinates of the points were loaded into a GPS (Garmin 76S or Garmin II+ Differential unit). Typical accuracy of these units is 15m without Wide Area Augmentation System (WAAS) enabled (Garmin 2006-2010). Accuracy is greater with WAAS, which was enabled in July 2003, prior to the accuracy assessment field season. The accuracy assessment observers used the GPS to navigate to each accuracy assessment point. Upon arriving at the point, the observer used the field key and descriptions to assess what association (or Anderson Level II land cover category) occupied the observation area 28.2 meters around the point. The appropriate association was recorded on a field form. If other associations were found in the observation area, or if the vegetation could reasonably be interpreted to be more than one map class/association, the alternative types were noted as well. This information was used to assist in assessing cause for errors. The position of the point as measured by the GPS and the GPS error were recorded in the field to assess whether positional error may be confounding in assessing error causes for individual points. 2004 The shapefile was imported into a geodatabase by the USGS/CSS/Core Science Analytics and Synthesis. 201206 Metadata imported. 201206 Vector Entity point 235 Universal Transverse Mercator 18 0.999600 -75.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000100 0.000100 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 THST_VegPoints Feature class attribute table National Park Service OBJECTID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Plot_Code Unique identifier for this Accuracy Assessment, Observation or Plot point NPS Geodatabase V3.2 Unique plot number. Pnts_Type Point type (accuracy assessment point, observation point or plot point) NPS Geodatabase V3.2 Accuracy Assessment Point AA Point NPS Geodatabase V3.2 Observation Point Observation Point NPS Geodatabase V3.2 Plot Point Plot Point NPS Geodatabase V3.2 X_Coord X Coordinate (UTM Easting) NPS Geodatabase V3.2 Easting coordinate. Y_Coord Y Coordinate (UTM Northing) NPS Geodatabase V3.2 Northing coordinate. rc_VegPoints_tAA_tPlots Defines relationship between Veg points and basic AA/plot attributes National Park Service USGS/CSS/Core Science Analytics and Synthesis USGS-NPS Vegetation Characterization Program Coordinator mailing and physical address

Denver Federal Center, Building 810, MS 302

Denver Colorado 80225 (303) 202-4220 303-202-4219 gs-b-npsveg@usgs.gov Downloadable Data The U.S. Geological Survey and the National Park Service shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data and related graphics (if available) are not legal documents and are not intended to be used as such. The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. Any related graphics (if available) are intended to aid the data user in acquiring relevant data; it is not approriate to use the related graphics as data. The U.S. Geological Survey and the National Park Service gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from an U.S. Geological Survey and National Park Service servers and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. Mention of trade names or commercial products in this metadata report does not constitute endorsement or recommendation for use by the U. S. Department of the Interior, U. S. Geological Survey and National Park Service. HTML http://www.usgs.gov/core_science_systems/csas/vip/parks/thst.html Internet Access None 20110516 20120617 USGS/CSS/Core Science Analytics and Synthesis USGS-NPS Vegetation Characterization Program Coordinator mailing and physical address

Denver Federal Center, Building 810, MS 302

Denver Colorado 80225 (303) 202-4220 303-202-4219 gs-b-npsveg@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999 http://www.usgs.gov/core_science_systems/csas/metadata/index.html