II 



Cowardin et al. 



Fig. 11. Examples of palustrine scrub-shrub wetlands, (a) Northern leatherleaf bog and (b) pocosin. 



Palustrine Scrub-Shrub Wetlands 



Freshwater wetlands dominated by woody vegetation 

 less than 20 feet tall represent palustrine scrub-shrub wet- 

 lands (Figure 11). Although not as abundant as palustrine 

 emergent and forested wetlands, they occur widely 

 throughout the Nation. These shrub-dominated wetlands 

 are commonly called "bog", "pocosin". "shrub-carr", or 

 "shrub swamp" in different parts of the country. 



Northern and southern peat bogs are particularly inter- 

 esting types of scrub-shrub wetlands. Both types are rare- 

 ly flooded and are generally characterized by a saturated 

 organic soil with the water table at or near the surface for 

 most of the year. Northern bogs are prevalent in isolated 

 depressions, along river courses and along the margins of 

 lakes in states like Alaska, Maine, Michigan, Minnesota, 

 New York and Wisconsin. Typical northern bog plants 

 include leatherleaf, sweet gale, cotton grass, peat moss, 

 bog rosemary. Labrador tea, cranberry, bog laurel, and 

 sedges as well as stunted trees of black spruce, larch, 

 lodgepole pine, and balsam fir. Southern bogs occur 

 along the southeastern Coastal Plain and are locally called 

 "pocosins." They are found on broad flat plateaus usually 

 apart from large streams. Pocosins are dominated by 

 evergreen shrubs of pond pine, sweet bay, inkberry, fet- 

 terbush and titi. Other important scrub-shrub wetlands in 

 the U.S. are characterized by buttonbush. alders, wil- 

 lows, dogwoods and saplings of tree species like red 

 maple and Cottonwood. 



Palustrine Forested Wetlands 



Forested wetlands dominated by trees taller than 20 

 feet occur mostly in the eastern half of the United States 

 and Alaska (Figure 12). In the East, they are the most 

 abundant wetland type. They include such diverse types 

 as black spruce bogs, cedar swamps, red maple swamps, 

 and bottomland hardwood forests. In the Prairie Pothole 



Region of the Dakotas, forested wetlands are relatively 

 uncommon. As in other inland wetlands, flooding is ex- 

 tremely variable depending on regional climate, topo- 

 graphic position and local hydrology. In the North, 

 important trees of the wetter swamps are red maple, 

 ashes, northern white cedar, black spruce and larch. Bald 

 cypress, water tupelo. red maple, black gum. Atlantic 

 white cedar, overcup oak, and black willow are common 

 in southern wet swamps. In the Northwest, western hem- 

 lock, red alder and willows are important species. Drier 

 swamps, those flooded only briefly during the growing 

 season, are characterized by silver maple, pin oak, syca- 

 more and beech in the North and by sweet gum, loblolly 

 pine, slash pine, tulip poplar, beech, black walnut, syca- 

 more, water hickory, pignut hickory and various oaks 

 (e.g., water, laurel, and willow) in the South. Cotton- 

 wood, box elder, willows, green ash and elms dominate 

 riparian wetlands along western streams. Black spruce, 

 larch, lodgepole pine and balsam poplar are the major 

 forested wetland species in Alaska. 



References 



Cowardin. L.M., V. Carter, F.C. Golet. and E.T. LaRoe. 1979. Classi- 

 fication of Wetlands and Deepwater Habitats of the United States. 

 U.S. Fish and Wildlife Service. FWS/OBS-79/31. 103 pp. 



Hofstetter, R.H. 1983. Wetlands in the United States. In: A. J. P. Gore 

 (editor). Mires: Swamp, Bog. Fen and Moor. Elsevier Scientific 

 Publishing Co.. Amsterdam, pp. 201-244. 



MacDonald. K.B. 1977. Plant and animal communities of Pacific North 

 American salt marshes. In: V.J, Chapman (editor). Wet Coastal 

 Ecosystems. El.sevier Scientific Publishing Co.. Amsterdam, pp. 

 167-191. 



Reimold, R.J. 1977. Mangals and salt marshes of eastern United States. 

 In: V.J. Chapman (editor). Wet Coastal Ecosystems. Elsevier Scien- 

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Shaw, S.P. and C.G. Fredine. 1956. Wetlands of the United States. 

 Their Extent and Their Value lo Waterfowl and Other Wildlife. U.S. 

 Fish and Wildlife Service. Circular 39. 67 pp. 



Stewart, R.E. and H. A. Kantrud. 1972. Vegetationof Prairie Potholes, 

 North Dakota, in Relation to Quality of Water and Other Environ- 

 mental Factors. U.S. Geol. Survey. Prof. Paper 585-D. 36 pp. 



