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Central Maine Embayment

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About the Central Maine Embayment

The Central Maine Embayment is a large region in the interior of Maine. This regions is both high in biodiversity and important to humans.

This region consists of rolling plains with some hills of varying sizes. There are numerous small lakes, some swamps and bogs, and some large river valleys and low to moderate gradient streams. The bedrock consists of metasedimentary rocks of varying grain sizes, but many of them calcium-rich. There is also some granite and metavolcanic rock. This is covered with more recent marine deposits and glacial till, and there are glacial features including eskers and kame terraces. The high calcium content in soils tends to buffer this region's soils and waterways against acidity, and make it more suitable for farming than most areas this far north.

Plant biodiversity is high relative to the surroundings, and many species reach their northern limits here. Original forest cover was mostly a transitional white pine - mixed forest ecosystem. White pine-mixed conifer forests featured eastern white pine (Pinus strobus), red spruce (Picea rubens), eastern hemlock (Tsuga canadensis), and red maple (Acer rubrum). There was also northern hardwood forest featuring sugar maple (Acer saccharum), American beech (Fagus grandifolia), and yellow birch (Betula alleghaniensis), and oak-pine forest featuring red oak, white pine, red maple, and paper birch (Betula papyrifera). Floodplains featured silver maple (Acer saccharinum), red maple, American elm (Ulmus americana), black ash (Fraxinus nigra), and bur oak (Quercus macrocarpa).

Current land use is a mix of forest and agriculture. There is some pastureland as well as cropland that produces mostly silage corn, potatoes, and hay. This is the most populous interior region of Maine, including the cities of Augusta, Lewiston, and Waterville, and it has a dense road network, which leads the forests here to be highly fragmented, even if total forest cover is high. There is some forestry, but generally less than some of the more interior regions.

To the south, this region is bordered by the Midcoast, a region with a more ocean-moderated climate and often rockier soils. To the west there is a border with the Sebago-Ossipee Hills and Plains, and north of that, the Western Maine Foothills; these regions are higher elevation, cooler, and have less fertile soils and lower plant biodiversity. In the north there is a small border directly with the Quebec/New England Boundary Mountains, but most of the region is bordered to the north by the Central Foothills, a transitional region to those mountains. To the east lies the Penobscot Lowlands, and south of that there is a small border to the east with the Eastern Maine-Southern New Brunswick Plains. There is also a small border to the southeast with the Downeast Coast.

References

1. Griffith, G.E., Omernik, J.M., Bryce, S.A., Royte, J., Hoar, W.D., Homer, J.W., Keirstead, D., Metzler, K.J., and Hellyer, G. "Ecoregions of New England (Poster)", U.S. Geological Survey (2009) Web.