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Study Sites & Design

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BNWR near Cambridge, MD is located on the eastern shore of the Chesapeake Bay on a low-lying terrace of the Delmarva mainland in an area of low elevation and relief. The marsh is brackish and dominated by Olney 3-square (Schoenoplectus americanus), saltgrass (Distichlis spicata), saltmarsh cordgrass (Spartina patens) and black needlerush (Juncus roemerianus). This marsh is typical of those brackish marshes found along the eastern and Gulf coasts of the United States.

MixedMarshSpartinaRegrowth
photos by Jim Lynch
 
Fig. 6. (left) Mixed Spartina patens and Schoenoplectus americanus community in BNWR and (right) new shoots of Spartina patens following a prescribed burn at BNWR

BWBlocks

In 1998, BNWR initiated a long-term prescribed burn experiment in response to concerns about the potential impacts of annual burns on soil organic matter accumulation, and ultimately marsh loss.  Three study areas, or blocks, were selected for the experiment within BNWR (Fig. 7). Each of the three blocks is subdivided into 4 subunits to which one of 4 treatments (annual burn, 3 - 5 year burn rotation, 7 - 10 year burn rotation and no burn control) is applied. Prescribed burns are conducted within each block from January 1 to March 15 following a formula used since 1970 of temperature, humidity, winds, and soil moisture that ensures a surface burn with 1 – 2” of vegetative stubble remaining. For this study, we established 3 plots within each treatment level–block combination for a total of 36 experimental plots in which we measured elevation change and other biological and chemical variables (e.g., Fig. 8).


Fig. 7. Aerial imagery showing BNWR boundaries
and location of experimental blocks

 

 

Treatments

Fig. 8. Aerial imagery showing an experimental block, including subunits, burn treatment applications, and experimental plots.

 

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