Spruce Lake Bog

State Natural Area (No. 59)

Location: Within Northern Unit Kettle Moraine State Forest, Fond du Lac County. T14N-R19E, Sections 22, 23. 140 acres.

Access: From the intersection of State Highway 67 and County Highway F in Dundee, go west on F 0.2 mile, then north on Vista Drive 1.3 miles, then west on Airport Road 0.5 mile to a parking area north of the road. A trail and boardwalk lead to the lake.

Description: Spruce Lake Bog features an undisturbed shallow seepage bog lake situated in one of the many kettle holes characteristic of the interlobate glacial deposits scattered throughout the area. The 35-acre lake has moderately hard water with a pH of 7.5 and supports a dense, floating-leaved aquatic flora of water shield and water lilies. The site is particularly rich in plants more characteristic of northern Wisconsin sphagnum bogs and greatly resembles them in appearance. Black spruce, which is common in the swamp forest, is near its southern range limit in Wisconsin. Distinct vegetation zones encircle the lake with a floating sedge mat of cotton grass, three-fruited sedge, royal fern, pitcher plant, round-leaved sundew, moccasin flower, wintergreen, and small cranberry grading into a bog forest of tamarack and black spruce. An outer zone of swamp hardwoods includes tamarack, black ash, red maple, yellow birch, and white cedar and contains species more commonly associated with northern coniferous forests including three-leaved gold-thread, American starflower, partridgeberry, common winterberry, and yellow blue-bead lily. The diversity of shrubs on the sedge mat and in the forest is indicative of the area’s high quality. Species include speckled alder, black chokeberry, willow, round-leaved and red-osier dogwood, Labrador-tea, bog birch, leather-leaf, bog-rosemary, poison sumac, mountain holly, meadowsweet, huckleberry, cranberry, and blueberry. Several bird species with northern affinities nest here, including northern waterthrush, Nashville warbler, Canada warbler, and white-throated sparrow. Spruce Lake Bog has been designated a national natural landmark by the US Park Service. Spruce Lake Bog is owned by the DNR and was designated a State Natural Area in 1968.