Carolina Environmental Diversity Explorations
Large sand volume barrier islands · By Dirk Frankenberg
Fort Macon State Park
Figure 12. Dunes at Fort Macon State Park on Bogue Banks. (Photograph by the author. More about the photograph)
Figure 12 shows the dunefield at Fort Macon State Park on Bogue Banks. This is a typical setting for maritime shrub and forest development. Note the large and well vegetated dunes. These raised mounds of sand are called hummocky dunes — a form that normally develops when 45 to 75 percent of the dune surface is vegetated. That level of vegetation must have occurred some time in the past, because these dunes are clearly more heavily vegetated than that now.
The live oak trees in the foreground have dead twigs in their crowns. These were killed back by salt spray. Their repeated die-off causes the forest canopy to be wedge-shaped, as you can see behind the hummocky dunes in the background. This wedge shape is the multiplant equivalent of the flagging we saw on an individual live oak on Bear Island. As is the case with flagging, wedged forest canopies tell you the direction from which the most salt-laden wind has been blowing. Note that all the wedges have their lowest edge facing in the same direction.
