releve Virginia Division of Natural Heritage, see http://www.dcr.virginia.gov/natural_heritage/documents/nh_plotform_instructions.pdf
Overall Taxon Cover Values are Automatically Calculated?
no
Stem Observation Area
400
m²
Plot Quality Fields:
Plot Validation Level
(2) classification plot: sufficient for inclusion in a classification revision
Overall Plot Vegetation Fields:
Tree Height
9
m
Shrub Height
6
m
Field Height
1
m
Tree Cover
2
%
Shrub Cover
50
%
Field Cover
40
%
Nonvascular Cover
15
%
Misc Fields:
Observation Narrative
The plot is located on a large, rocky bar which developed at a knickpoint where diamictite bedrock extends into the Potomac river and forms the channel shelf. Much of the bedrock is now covered, or weathered into large boulders and stones by frequent high-energy scouring. Small pools among the rocks were dry on the date of sampling. Much of this area supports Justicia americana herbaceous vegetation, but the plot captures a small inclusion (not much larger than the 400 sq. m. plot) of flood-battered woodland dominated by Diospyros virginiana and Platanus occidentalis. The associated herbaceous flora is very diverse but contains numerous weedy exotics. The hydrology and soil moisture regime are ambiguous and difficult to characterize. The rocky substrate is apparently inundated for large portions of the year but subject to droughty conditions when exposed for prolonged periods in the summer and fall.
