Above is a typical Bigwoods Remnant Forest in SE Minnesota |
Bigwoods
of Minnesota
A Brief History |
Oak Savanna/Woodland |
The Bigwoods were a large area of deciduous forest surrounded by prairie that occupied much of south-central Minnesota. The existence of this tongue of forest surrounded by prairie -- and its associated fires -- was the cause of much discussion in the 19th century and has been the subject of several research projects since. J. McAndrews in the 1960s and Eric Grimm again in the 1980s reconstructed the long-term history of the Bigwoods based on pollen analysis and changes in sedimentation. Both suggested that a reduction in fire frequency coincident with the onset of the 'Little Ice Age' ( cool/moist period from ~1250 AD to 1850) was the trigger for the expansion of the Big Woods; a competing hypothesis is that a reduction in Native American populations due to disease was responsible for a drop in fires but there is very little data to address this hypothesis directly. Grimm showed that the borders of the Bigwoods corresponded with the location of rivers and lakes and other features of the landscape that would have acted as fire breaks. My students and I are trying to better
understand the relationship of fire to the rise of the Big Woods, examining
I have also been working with Phil Camill (Carleton), Christoph Geiss (Trinity College), and Becky Teed (LRC, University of MInnesota) on cores from two lakes in the Bigwoods (Kimble Pond and Sharkey Lake) both of which have sediment records that extend 10-12000 years. We have published several papers based on these two sites. The results from this work indicate that the Big Woods has been a mosaic of woodland and grassland since at least 9000 years ago and that changes in fire (frequency and/or intensity) may be the product of climate-driven changes in fuels. Selected References |
Close-up of Prairie in Fall |
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Prairie Fire |