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
31
m
Field Height
1
m
Tree Cover
75
%
Field Cover
40
%
Misc Fields:
Observation Narrative
Plot is located ca. 300 m from the main channel of the Meherrin River, near the outer edge of an extensive, deeply flooded backswamp that was drawn down but still quite wet on the date of sampling, despite months of extended drought. The forest vegetation is completely dominated by medium-size to large Nyssa aquatica, with water marks averaging ca. 50 cm above the soil surface. Other parts of the stand have a moderately dense shrub layer of Fraxinus caroliniana and very sparse herbs, but we chose to sample a portion with virtually no woody understory and a more diverse herb flora. Stand age was estimated by International Paper as > 99 years. Flooding at this site is deep and persistent enough to mostly limit herbaceous species to 1) floating aquatics and species capable of rooting in shallow water, e.g., Azolla caroliniana, Lemna perpusilla (dominant in some areas), Proserpinaca pectinata, and Hydrocotyle verticillata var. verticillata, and 2) species capable of rooting on mossy tree bases and logs, e.g., Bidens discoidea (dominant), Bidens connata, Triadenum walteri, Lycopus rubellus, and Ludwigia leptocarpa. Adjacent to this stand toward the river is a beaver-impacted area of sparse, standing-dead trees, patches of Typha, and abundant Bidens spp.
0-5 cm: black organic matter, silt, and litter
5-15+ cm: dense gray clay with orange mottling
Soil wet at time of survey.
Disturbance Data:
Disturbance Type
Disturbance Intensity
Disturbance Comment
unknown
Adjacent beaver activity appears to currently impact this stand only indirectly. However, it may have increased the prevalent hydroperiod, and there are many small, old stumps throughout the swamp; it is unclear whether these are from altered hydrologic conditions over time or from very old beaver cuttings.
