The cedar swamp forests along the Alligator 

 River are nonalluvial in the sense that the Alligator is 

 an estuary or embayed stream that neither transports 

 a heavy sediment load nor has frequent high over- 

 bank flows. The mainland Dare swamp forests are 

 physiognomically and hydrologically distinct from 

 swamps of brown-water river flood plains; however, 

 they appear to be more similar to those distant 

 riverine swamps than to the nearby pocosins (see 

 Section 7.3, esp. Section 7.3.4). 



Pocosins and pure and mixed cedar forests 

 are found on a similar range of peat depths. Charcoal 

 layers sandwiched within forest peat profiles indicate 

 that fire has occurred in such swamps without subse- 

 quent pocosin development (Otte 1981). Otte con- 

 cludes that water-flow patterns are the major 

 difference between cedar swamp forest and pocosin 

 sites. In these swamp forests, the water flow is pri- 

 marily into and through the systems; in nearby areas 

 supporting pocosins, the major flow is out of the sys- 

 tem. A large amount of Dare County cedar swamp 

 water comes in from surrounding high ground or 

 through flowing streams that carry clay and dis- 

 solved nutrients, whereas the major source of 

 pocosin water is precipitation. Consequently, the 

 peat that supports swamp forests has a higher 

 average mineral content than does peat underlying 

 pocosins (Otte 1981). 



The flat terrain, combined with the high 

 evapotranspiration rate of the dense vegetation and 

 the low hydraulic conductivity of the organic soils of 

 undisturbed cedar wetlands, causes water to move 

 very slowly, predominantly overland, and through the 

 root/litter mat (Skaggs et al. 1980; USFWS, unpubl. 

 b). Historically, drainage patterns would have been 

 overland to stream systems and thence into the 

 nearest river or sound. However, the peninsula has 

 been altered by highway and canal construction 

 resulting in rapid drainage pathways generally less 

 than 1.6 km long (USAGE 1982). The pattern of 

 hydrological change is very similar to that of the 

 Great Dismal (see Section 2.4.1), but the alterations 

 are not as drastic. 



7.2.5 Climate 



The Albemarle-Pamlico peninsula has a 

 temperate climate with warm summers and mild 

 winters. Winter temperatures seldom fall below -12 

 °G and summer temperatures often exceed 32 °G in 

 July and August; humidity is usually high. The 

 freeze-free season in mainland Dare County is 1 80 to 

 220 days long (USAGE 1982). Precipitation 

 averages from 1 14 to 137 cm per year, with peaks 

 generally occurring July as a consequence of sum- 

 mer thunderstorm activity. Fall is usually the season 



of minimum rainfall. Annual amounts may be as low 

 as 89 cm during dry years and as high as 203 during 

 unusually wet years (USAGE 1982). Because the 

 Dare peninsula is surrounded by water, it is subjected 

 to a strong coastal sea breeze regime. Prevailing 

 winds are from the south-southwest, with average 

 speeds of 14 to 17 km/hr (Copeiand et al. 1983; 

 USAGE 1982). 



7.2.6 Tidal Influence 



The Dare peninsula is largely protected from 

 the influence of lunar tides by the coastal barrier is- 

 lands to the east, although dampened lunar tides of 

 small magnitude do occur Wind-generated tides are 

 the principal source of water-level fluctuation within 

 sounds, the Alligator River, and Milltail Creek. In the 

 river and creek, rising tides usually result from west- 

 northwest through east-southeast winds with falling 

 tides usually resulting from southwest through west- 

 southwest winds. Mainland Dare is subject to tidal in- 

 undation only under extreme conditions, and zones 

 of flood-killed vegetation border the sounds where 

 this has occurred (USAGE 1982). 



7.3 VEGETATION 



7.3.1 Introduction 



Atlantic white cedar associations, par- 

 ticularly the dense, monospecific stands, have inter- 

 ested North Carolina botanists and ecologists for 

 sometime (Ashe 1894a, b; Korstian 1924; Wells 1932; 

 Buell and Cain 1943). However, it was not until the 

 early 1 980's, when attention was focused on pocosin 

 and peatland losses, that any descriptive material or 

 quantitative data on the vast coastal cedar peatlands 

 was gathered. Natural area studies for mainland 

 Dare, Hyde, and Tyrrell Counties (McDonald and Ash 

 1981; Peacock and Lynch 1982; and Lynch and 

 Peacock 1982) are the principal published sources of 

 information on white cedar associations of the peat- 

 land region. Unpublished substantiating data has 

 been provided by intensive vegetation sampling by 

 the USFWS Ecological Services Office. Wetland 

 mapping for Dare County as a part of the National 

 Wetlands Inventory project (USFWS, progress 

 reports) has provided additional information. 



Macrofossils in the peat profile indicate that 

 white cedar has long been a component of the mixed 

 swamp forests that dominate the western half of the 

 Dare mainland (Otte 1981). The role that spon- 

 taneous fires, lightning, saltwater flooding, and hurri- 

 cane windthrow played in originally opening habitat 

 for white cedar colonization is completely obscured 

 by the area's history of extensive timbering. The 



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