Big Woods Forest
This was the most common type of forest in Rice County at the time of Euroamerican settlement in the 1850s. Today this forest is dominated by sugar maple and basswood and you will also see many red oak. Look also for white and green ash, black walnut, and even a few sulfur-bud hickory. Elm used to be the most important tree in this forest but was virtually eliminated by Dutch Elm disease. The forest floor is home to a rich array of ferns and spring ephemerals. Spring ephemerals grow, flower and go dormant in just two months (April-May) taking advantage of fact that leaves on trees are not fully expanded. Common spring ephemerals include trout lily, spring beauty, trillium and hepatica. Approximately 60% of the Cannon River Wilderness Area is lowland forest.
Lowland forest is associated with rivers and is characterized by periodic flooding and water-logged soils. The soils are silty and easily erodible. Common trees include ash, silver maple, box elder and black willow. Elm used to be an important species until Dutch Elm disease wiped out the older trees in the late 1970s. Notice how many of the trees have multiple trunks; this is most often a result of damage by ice and other debris during spring flooding. Approximately 12% of the Cannon River Wilderness Area is lowland forest.
Fen and Meadow
The wetland beyond this sign is a calcareous fen surrounded by a sedge meadow. The fen is calcareous because it is fed by cold, oxygen-poor groundwater rich in calcium and magnesium which accumulates as a whitish ‘marl’ in pools. As a result of the characteristics of the water, peat (partially decomposed plant material) accumulates and if you look carefully you will see that the entire fen area is elevated by 6-10 feet above the surrounding ground. This fen has many unique and rare plant species. The most abundant plant in this fen is the ‘tussock’ sedge that forms mounds. Sedges look like grasses but the base of a sedge is triangular, not round like a grass. Willow and other shrubs – including hazelnuts near the edge — are invading the fen which is why controlled burns are used to maintain the open nature of the fen. This area represents about 6% of the park but another 20% of the park, near the river is non-calcareous sedge wetland.
This area is known as an oak savanna which were once common throughout Rice County. A savanna is a grassy prairie area with scattered “open-grown” oaks. “Open grown” means the main branches of the trees are spreading. Oaks were the most common tree in savannas because their thick bark made them resistant to the many fires that burned the grasses and killed more fire sensitive trees and shrubs. This savanna is a bit unusual in that the most com tree is a red oak. White oak and burr oak are also found here. The most common prairie grass in this savanna is little bluestem which turns a beautiful purple in the Fall. Notice also the round-headed bush clover. Fire and brush cutting are currently being used as tools to keep this savanna open.