Rib Mountain Talus Forest

State Natural Area (No. 532)

Location: Within Rib Mountain State Park, T28N-R7E, Sections 8, 17. 215 acres.

Access: From the County N exit of Highway 51/I-39, go west on County N 0.2 miles to Park Road. Follow the road 2.3 miles to a parking area. Hiking trails wind through the site.

Description: Rib Mountain Talus Forest is a unique site that supports three rare plant species found among the scattered quartzite rocks on the south side of Rib Mountain. Formed 1.5 billion years ago and standing 640 feet above the surrounding landscape, the mountain is composed of a single large block of quartzite, as are its two nearest neighbors, Mosinee Upper Hill and Hardwood Hill. Rib Mountain is actually a monadnock, a general term for a conspicuous hill that stands above the surrounding plain on account of the resistance of the rock of which it is composed. Being made of hard, durable quartzite, Rib Mountain has thus resisted being worn down to the same degree as the surrounding rocks. The site supports an extensive second-growth mesic forest of sugar maple, paper birch, red oak, and big-tooth aspen. Larger trees present in patches or as individuals including basswood, white ash, red maple, and yellowbud hickory. Scattered conifers are occasionally present but are greatly reduced from their historic abundance. Richer areas support groundlayer plants such as Virginia water-leaf and maidenhair fern while areas with thin soils where quartzite outcrops and talus occur contain plants associated with drier and generally more infertile conditions. Unique microhabitats within crevices of the jumbled talus support rare plants including purple clematis (Clematis occidentalis), Missouri rock-cress (Arabis missouriensis), and the state-threatened drooping sedge (Carex prasina). Rib Mountain Talus Forest is owned by the DNR and was designated a State Natural Area in 2005.