Historical Patterns and Contemporary Processes in Northern Lake States Old-Growth Landscapes

Abstract

Understanding the value of remaining old-growth forest requires that we evaluate it in the spatial context in which it occurs and in the alterations of that context over the last 150 years. We can see this visually at the regional scale. The northern Lake States forests of Minnesota, Wisconsin, and Michigan, are at the northwestern edge of the north temperate forest of eastern North America (plate 4). This generalized map of forests before widespread Euro-American settlement shows a legacy of responses to physical environment and disturbance, with the upper Midwest ecotone or tension zone generally separating the more northern evergreen-deciduous forested region from the more southwestern oak savanna and prairie. Western limits of beech, hemlock, and yellow birch as major dominants are indicated by black lines. The edges of the beech and hemlock range were particularly abrupt. Yellow birch was in scattered stands and locally abundant as it declined in abundance into northeastern Minnesota. Pines are generalized here but usually occurred over large areas as one or two dominant species.