Carolina Environmental Diversity Explorations
Wetlands of the coastal plains · By Dirk Frankenberg
Coastal plain bottomland forest
Figure 7. A hardwood community along the Northwest Cape Fear River in Pender County. (Photograph by the author. More about the photograph)
Figure 6 illustrates a fine river to tour: the Northwest Cape Fear, as it appears in Pender County. The wetland type we see on the far bank is a coastal plain bottomland hardwood community.
These communities develop on irregularly flooded habitats along rivers. The specific community is different on blackwater rivers (those that originate in the coastal plain) than along brownwater rivers (those that originate in the piedmont or the mountains). As a result of their smaller drainage basin, blackwater rivers carry less sediment and have more rapid changes in waterflow than their bigger brownwater cousins. The differences between the forests on the two river types is subtle and better left to professional botanists. Both community subtypes are dominated by combinations of oaks, pines, maples and gums. Red maples, magnolia, and hollies occur in the understory beneath the larger trees. The diversity and distribution of plants within these communities is made more variable by their riverside location.
Floods and droughts disturb the soils and plants of these habitats, sometimes eliminating whole sections of forest. As a result, every specific habitat you look at is a mix of recently and long established trees. Forest ecologists call this mix a mosaic community. An example of the loss of one major species in southeastern North Carolina bottomland hardwood forest is the loss of almost all loblolly pines after Hurricane Fran. Salt spray from the storm weakened the trees, winds uprooted others, flooding weakened the survivors still further, and to make matters worse, the warm winter that followed allowed an outbreak of pine bark beetles. The combination eliminated almost all if not all loblollies from lower coastal plain forests of many types. If you look at Figure 7 carefully, you will see dead pines among the leafless but surviving hardwoods.
