Rock Island Woods

State Natural Area (No. 382)

Location: Located within Rock Island State Park, Door County. T34N-R30E, Sections 14, 22, 23, 24. 570 acres.

Access: Most visitors reach the area by taking the Washington Island ferry from Northport to Detroit Harbor then drive to Jackson Harbor and take the passenger ferry to Rock Island. No motorized vehicles are allowed.

Description: Rock Island Woods features a mosaic of plant community types including a northern hardwood forest, northern wet-mesic forest, forested seeps, and shaded cliff community. The interior plateau of Rock Island contains a mature mesic hardwood forest dominated by beech and sugar maple. Canopy associates include basswood and red oak. Groundlayer species are wild leek, spring-beauty, trout-lily, large-flowered trillium, common lady fern, blue cohosh, and jack-in-the-pulpit. Rare plants include drooping sedge (Carex prasina), Chilean sweet cicely (Osmorhiza berteroi), broad-leaf sedge (Carex platyphylla), and climbing fumitory (Adlumia fungosa). Several moist swales and forested seeps are found on north-facing depressions within the forest containing herbaceous species such as ostrich fern, clustered snakeroot, hairy sedge, and squirrel corn. Dolomite cliffs and ledges occur on the margins of the forest and some support an upland stand of nearly pure white cedar with some balsam fir and white birch along the rocky coastline. About 4 linear kilometers of low moist shaded dolomite cliffs are found in the interior of Rock Island. These moist seepage slopes support a lush growth of ferns with bulbet bladder, fragile, walking, slender cliff brake, northern wood, and intermediate wood ferns. Bird life is diverse with spotted sandpiper, cliff swallow, veery, ovenbird, American redstart, and Canada, blackburnian, and black-throated green warblers. Rare plants and animals include common tern (Sterna hirundo), Caspian tern (Sterna caspia), northern ringneck snake (Diadophis punctatus edwardsii), rock whitlow-grass (Draba arabisans), and mystery vertigo (Vertigo paradoxa), a land snail. Rock Island Woods is owned by the DNR and was designated a State Natural Area in 2002.