stratification (canopy-subcanopy-tall shrub) . On the best 

 sites swamp black gum forms a closed canopy. Isolated 

 large gums up to 32 inches dbh are scattered throughout 

 the community along with several other species which 

 reach the canopy but are not dominant: loblolly pine 

 ( Pinus taeda ) , bald cypress ( Taxodium distichum) , sweet- 

 bay ( Magnolia virginiana) , and Atlantic white cedar 

 ( Chamaecyparis thyoides) . The subcanopy dominated by 

 red maple also contains the tree species mentioned above. 

 Redbay forms a dense tall shrub layer ranging from 10-25 

 feet in height. There is no dominant ground cover al- 

 though species such as chain ferns ( Woodwardia areolata , 

 W. virginica, sedges (Carex spp.) , and royal fern 

 ( Osmunda regalis var. spectabilis) are scattered through- 

 out. 



Vines are abundant in the community and include high- 

 climbing species such as poison ivy ( Rhus radicans ) , grape 

 ( Vitis sp.) , laurel-leaved greenbriar (Smilax laurifolia) 

 and yellow jessamine ( Gelsemium sempervirens) . During 

 April when the yellow jessamine is in bloom, the flowers 

 attract myriads of swallowtail butterflies including 

 species such as palamedes , black, tiger, and spicebush . 



There are minor variations in species composition of 

 the three layers . In some areas red maple does not form 

 a dense subcanopy. In other places red maple and sweet- 

 bay are co-dominants in the subcanopy. Truly large speci- 

 mens of sweetbay are common throughout. Individuals of 10 

 inches dbh are common and some trees measure up to 14 inches 

 dbh. Many are 60-75 feet tall. Sweet pepperbush (Clethra 

 alnifolia) forms a locally dense low shrub layer, particu- 

 larly along the canal banks where mineral spoil soils are 

 exposed. 



The swamp blackgum stands represent the least dis- 

 turbed sections of the swamp forest. Scattered very old 

 stumps of Atlantic white cedar and cypress indicate the 

 area was selectively timbered, probably during the early 

 1900' s, a period during which many extensive logging oper- 

 ations were underway in Washington County (Pat White, pers . 

 coram., 1982) . In those days, narrow gauge tramroads were 

 built into the vast swamp areas and mostly high quality 

 boles of cypress and cedar were removed. Today, large 

 cull trees of deformed cypress and cedar remain in the 

 swamp. Some cull cypress trees are up to 4 feet in di- 

 ameter and over 100 feet tall. Probably the original 

 swamp forest vegetation type of Van Swamp was cypress/ 

 swamp blackgum- Atlantic white cedar. Early descriptions 

 of cypress-dominated swamp forests are common in the 

 literature (Pinchot and Ashe, 1897; Ashe, 1894). 



15 



