Big Eau Pleine Woods

State Natural Area (No. 235)

Location: Within Big Eau Pleine County Park, Marathon County. T26N-R5E, Section 13. T26N-R6E, Section 18. 105 acres.

Access: From the intersection of State Highways 107 and 153 just east of Halder, go east on 153 0.3 mile to Eau Pleine Park Road, then south 6.3 miles to the parking area for the Giant Hardwoods Nature Trail west of the road.

Description: Big Eau Pleine Woods is an old-growth northern mesic forest located on a sloping peninsula that projects south into the Big Eau Pleine Reservoir, an impoundment of the Big Eau Pleine River. Sugar maple dominates the old growth forest with basswood, yellow birch, hemlock, and red oak. The largest trees occur on a small hilltop with a younger mixed-species forest occurring on the slopes. The gently rolling moraine contains numerous tip-up mounds and fallen, decaying trees afford a variety of microhabitats for plants and animals. The understory is rich with a diversity of spring ephemerals such as trillium, violets, hepatica, and bloodroot. Rare and uncommon nesting birds include cerulean warbler (Dendroica cerulea), Acadian flycatcher (Empidonax virescens), olive-sided flycatcher, and yellow-throated vireo. Big Eau Pleine Woods is owned by the Marathon County and was designated a State Natural Area in 1990.