The Eastern Transition and Great Lakes Forest Zones cover most of Wisconsin. Both are primarily mixed meadow and woodland, a far cry from presettlement periods when 85 percent of the state was covered by forest and the rest by tall grass. By the mid-19th century, those numbers had dipped to 63 percent forest, 28 percent savanna, and 9 percent grassland. Today, the state’s forest cover is 37 percent, and precious little of that is original. Of the two million acres of prairie that once covered the state, only 2,000 scattered acres survive. In all, Wisconsin has more than 2,100 species of plants, approximately a tenth of which are classified as rare, and some of them are threatened.

Four major vegetation types cover Wisconsin: boreal forest, a subarctic coniferous spread near Lake Superior; deciduous forest makes up the second-largest swath of Wisconsin woodlands; mixed forest, consisting of species of both, is found throughout the state; and nonforest/grasslands are found throughout the southern third of the state and up into west-central Wisconsin along the Mississippi River.

In settlement periods, Wisconsin had a huge expanse of wetlands, including more than 10,000 acres along Green Bay alone. Today, that amount has dwindled by more than half but still constitutes the largest amount remaining on the Great Lakes—a pathetic indication of rapacious development and overuse.