Coffey Swamp

State Natural Area (No. 276)

Location: On Washington Island, Door County. T34N-R30E, Sections 29, 30. 189 acres.

Access: From Detroit Harbor, go north and east on County W 5.8 miles. Park along the road and walk north into the natural area.

Description: Coffey Swamp occupies a former embayment of Lake Michigan along the northern coast of Washington Island. The natural area features a shallow, hard water seepage pond with a substrate of pure marl that nearly dries up in late summer and during years when the water level of Lake Michigan is low. Surrounding the pond is an open, treeless, boreal-rich fen dominated by wire-leaved sedges, sweet gale, and hoary willow. Boreal-rich fens are similar to their southern Wisconsin counterparts in having alkaline, saturated, peaty soils. They differ compositionally by having species more typical of nutrient poor northern wetlands such as round-leaved sundew, pitcher plant, cotton-grass, bog-rosemary, Labrador-tea, and bogbean. The fen also supports many rare plants, including tussock bulrush (Scirpus cespitosus), and false asphodel (Tofielda glutinosa). Adjoining the fen is a northern wet-mesic forest dominated by white cedar situated on peat over gravel and sand ridges. Deer browse is heavy and some areas are lacking in cedar reproduction. Coffey Swamp is owned by the DNR and was designated a State Natural Area in 1994.