The ecology of Atlantic white cedar wetlands - USGS National ...

1.4 ORIGINS AND MIGRATION OF CEDARFORESTSThe advance and wasting of glaciers stronglyInfluenced the topography of the land both underrhs glaciers and over the entire continent's coastalarea, due to direct glacial action, isostatic crustalmovement, and major variations in sea level. Duringaariior Interglacial periods, the northeast coast of theUnited States has been as far as 72 km further inlandthan today's shore; during the Wisconsin glaciation,stscl Ievei was as much as 60 to 80 m lower than itscurrent height (Bloom 1983). The extent and timingof sea level rise and fall remains controversial (Bloom1 983).Glacial melting from 17,000 to 10,000 yearsbefore the present (B.P.) led tothe formation of glaciallakes and outwash beds of various sizes. Glaciallakebeds, kettleholes of the glacial moraine, and outwashplain streambeds are landscape features thatnow support cedar communities in the Northeast(Figure 5). Further south, glacial meltwaters filledrivers and streams, the remnants of which now formthe stream bank and backswamp wetlands (Figure 6)in the New Jersey Pine Barrens, the Delmarva peninsula,Florida, and elsewhere. Such environmentsprovide habitats for cedar growth. Conditionspeculiar to the mid-Atlantic region are discussed inthe Dare County case study (Chapter 7).Figure 4 Cumloden Swamp. Falmouth. Massachusetts. Permanent high water, the result of damming by a'~(iway, IS causing tho slow death of mature cedars. This picture was taken fwe years after the road wasbuilt, and an@ year before the death of the last cedars.