St. Peter's Dome

State Natural Area (No. 420)

Location: Within the Chequamegon-Nicolet National Forest, Ashland County. T44N-R4W, Section 6. T45N-R4W, Sections 19, 20, 21, 28-33. 5,092 acres.

Access: The site is approximately 15 miles south of Ashland with access from FR 199 (County Line Road), which runs along the western boundary of the site. Hiking, x-country ski, and snowmobile trails give access to the interior.

Description: The highest point on the Chequamegon, St. Peter's Dome features a stream situated on a scenic chasm surrounded by a large block of unfragmented second-growth northern hardwood forest. The stream descends the Lake Superior escarpment in a gorge, which follows a fracture in Keweenawan granite. The gorge contains several low cliffs and occasional vertical cliffs, both moist and dry. Most of the lower gorge slopes are composed of moss-covered boulders 1-3 feet in size. The exposed bedrock features are used extensively by university groups studying Precambrian geology. The upland northern mesic forest contains extensive stands of maturing hemlock-hardwood and rich sugar maple-basswood forest along with significant inclusions of "old growth-like" forest. Other forest types include black ash-white cedar swamp, mixed swamp conifer, and dry-mesic forest. The northern mesic forest is dominated by rich sugar maple and basswood with scattered hemlock, yellow birch, white cedar, and pockets of mature white pine. Regeneration of white pine, hemlock, and white cedar is good and there are stable populations of Canada yew. The understory is rich with one of the most complete species assemblages on the Chequamegon-Nicolet National Forest. Shrubs include mountain maple, alternate-leaved dogwood, red elder, leatherwood, and American fly-honeysuckle. Herbaceous species include Carolina spring-beauty, trillium, bellwort, rosy twisted-stalk, trout-lily, wild leek, wild ginger, red baneberry, and blue cohosh. White mandarin (Streptopus amplexifolius), a species of special concern in Wisconsin is also present. Open cliff faces, talus and cliff tops support an overstory of white pine, red pine, white cedar, mountain maple, gooseberries, blueberry, and bearberry. Herbs include pale corydalis, columbine, long-leaved bluets, and numerous ferns. Of interest is the presence of three rare fern species: fragrant fern (Dryopteris fragrans), spreading wood fern (Dryopteris expansa) and state-threatened Braun’s holly fern (Polystichum braunii). Other notable features include the headwaters of several important cold water streams including Morgan, Frames, and Waboo Creeks, a full range of forest development in a natural matrix, the unroaded and remote nature of the site and the widest elevation gradient on the Forest (500 feet), and the 80 foot waterfall, Morgan Falls. St. Peter's Dome is owned by the US Forest Service and was designated a State Natural Area in 2007.