Kirby Lake Hardwoods

State Natural Area (No. 558)

Location: Within the Peshtigo River State Forest, Marinette County. T32N-R19E, Section 22. 111 acres.

Access: From the intersection of County Highway W and A in Crivitz, go west on County W 5.7 miles, then north on Kirby Lake Road 0.8 miles. The site lies east of the road. The natural area is located on both sides of the river.

Description: Located above the Sandstone Flowage, Kirby Lake Hardwoods is situated along a one-mile stretch of the Peshtigo River, here free-flowing through a narrow valley. The site supports patches of cedar swamp and mesic northern hardwood forest on the river terraces. Scattered mature red and white pines are found on the step sloes of the river. Hilly uplands are comprised of red oak, red maple, aspen forest with some areas of red oak, basswood, and sugar maple forest. Of note are areas of spring seepage that support a high quality northern wet-mesic forest (white cedar swamp) that contains a good amount of white cedar reproduction. Other species present include white pine, paper birch, and black spruce. The dense ground layer contains species such as three-leaved goldthread, naked miterwort, Canada mayflower, field horsetail, cinnamon fern, Canada bunchberry, yellow bluebead lily, and large-leaved aster. Rare plants include white adder’s-mouth (Malaxis monophyllos) and sheathed sedge (Carex vaginata). Kirby Lake Hardwoods is owned by the DNR and was designated a State Natural Area in 2007.