Anoka Ecosystems:
Aspen Woodland
Aspen woodlands are early successional communities, which means they are short-lived and historically maintained by fire. Occurring as an intermediate between aspen or oak forests and upland prairies, the incidence of aspen woodlands in Anoka County has increased as fire suppression techniques have been used. Fire supression allows smaller, more vulnerable trees and shrubs to thrive, thus supporting aspen woodlands.
The tree cover of Aspen woodlands are comprised of at least 70% aspens, though less than 25% may be conifers and herbaceous species may make up les than 30%. The canopy is dominated by quaking aspen, although in other regions big-toothed aspens or balsam poplars may be common. The understory is usually composed primarily of woody species including hazelnut, dogwoods, chokecherry and willows. The shrub layer often includes American hazel, downy arrowwood, Juneberry, and prairie willow, and characterized by tall and dense species. The community is present on dry and wet sites in association with other communities including oak and aspen forests along with wet meadows and wet-mesic prairies.
Though once thought to be found in several places in Anoka County, today this ecosystem is all but nonexistent in the region. The community is often relatively short-lived, so with the addition of human disturbance, the ecosystem became extremely rare. Disturbed aspen groves which resemble native woodlands can be found in Anoka County on drained wetlands, but these are not true apen woodlands because their understory is composed of only invasive species, such as reed canary-grass, common blackberry, or stinging nettle.
Sources:
"Minnesota Land Cover Classification System: User Manual." Version 5.3 Minnesota Department of Natural Resources, Central Region, 2004.
"Minnesota's Native Vegetation: A Key to Natural Communities" Version 1.5 Minnesota Department of Natural Resources, Natural Heritage Program, 1993.
Wovcha, D, B. Delaney, G. Nordquist. Minnesota's St. Croix River Valley and Anoka Sandplain: A Guide to Native Habitats Minneapolis: University of Minnesota, 1995.
