Manassas Bluff Flora

This database includes groundflora (including shrubs) and tree data collected as part of a survey of cliff vegetation in Manassas National Battlefield Park, Virginia, USA during May and August of 2014. Cliffs were defined as expanses of exposed, mostly vertical bedrock and associated slopes with significant exposed rock and a slope angle exceeding approximately 45 degrees. "Bluffs" include stretches of spatially related cliffs and slopes; "Blocks" comprising bluffs are differentiated from each other by slope, aspect, geologic strata, or the amount of exposed bedrock.\r\n\r\nEnvironmental data for each block include slope (degrees), aspect, and the percent cover of rock, bare soil, moss and lichen, leaf litter, down dead wood, and root and bole of live woody stems, and whether or not blocks end in water or include a seep. Groundflora and shrubs were identified to species and their percent foliar cover (see table "Cover values") within each block was estimated. Trees with a diameter at breast height (DBH) greater than or equal to 10 cm were identified to species and DBH was measured to the nearest centimeter. Photos were taken at various points along each bluff. A full description of the methods used to collect data can be found in the USGS data series that accompanies this database (Stroh and other, 2015)\r\n\r\nThis database uses forms and reports to provide quick access to data about specific bluffs or blocks. Forms allow you to specify which bluff or block for which to retrieve data. Photos were assigned a name based on the bluff, block, and a number. These can be accessed via hyperlinks in the "Photos" table.\r\n\r\nStroh, E.D., Struckhoff, M.A., and Grabner, K.W., 2015, A floral survey of cliff habitats along Bull Run at Manassas National Battlefield Park, Virginia, 2014: U.S. Geological Survey Data Series 940, 20 p.,\r\nhttp://dx.doi.org/10.3133/ds940.