Prairie
Forest Border
It's not prairie, it's not forest, it's border!
Source: NatureServe
Prairie
Forest Border
Source: NatureServe
The prairie-forest border is a unique area that represents the region
where the northern woodlands of Minnesota meet the prairie-dominated southern
areas of Minnesota. Because of the reoccurrence of natural fires,
natural firebreaks (bodies of water, geographic formations, etc.) are the
main factors in defining and sustaining the prairie-woodland line (Grimm).
In Rice County, the Cannon and Straight Rivers provide the major natural
firebreaks.
1847-1907 Natural Vegetation of Minnesota Source: Minnesota DNR 
1847-1907 Natural Vegetation of MinnesotaCurrent Rice County Prairie-Forest Border
Source: St. Olaf Biology Dept. WebpageCurrent Rice County Prairie-Forest Border
Fires are believed
to have been responsible for preventing the spread of deciduous forest into the
prairie. Although they did not burn every area each year, periodic fires
at intervals of 10 or 20 years were sufficient to kill most invading trees and
shrubs, thus maintaining a distinct border region. Controlled burns are
used in conservation strategies to mimic natural occurring fires and thus restore
prairie areas.
Mainly consisting of fire-tolerant oaks and aspen, the border region
varies in width, strongly dependent upon both the presence of additional
fire breaks, and the topography of the land. These factors help maintain
the border by shaping fire ranges and allowing prairie fires to kill back
any forest vegetation that is extending into the prairie (Tester).
The measurement of this irregular border line is described by determining
the expanse of the zones that are predominantly oak and aspen. Data
has also been collected where border zones (oak-aspen regions) do not even
exist (Grimm).
For more information on the history and development of this border environment, check out these links:
The Effects of Fire on the Prairie/Forest Border
in Southern Minnesota -- Erin Withers
The Role of Fire in the Distribution of
Oak Savannas before European Settlement of Minnesota -- Jenny
Makosky