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BY CYNTHIA PARSONS STORIES OF THE HEARTLAND
In Minnesota, oak savannahs( open grasslands with scattered trees) and oak woodlands were once widespread, covering about 10 % of native vegetation. Oak trees would have made up the majority of the forest canopy with an understory of native grasses and forbs( wildflowers). Prescribed fire, sometimes referred to as a prescribed or controlled burn, is a management strategy used to restore and maintain oak savannahs and oak woodlands which are transitional ecosystems. Transitional ecosystems sit right between wide-open grasslands( prairies) and closed-canopy forests. They rely heavily on fire to clear accumulated dead wood and prompt highly nutritious green grass to sprout. Fire rejuvenates pastures for cattle grazing and reduces the risk of uncontrollable
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wildfires.
Most of Minnesota’ s ecosystems were fire dependent or at least fire tolerate and subject to frequent cultural burnings by indigenous Americans. For thousands of years, these landscapes were primarily managed by fire and the grazing activity of wild herds of elk, deer, bison, etc. depending on where you lived in the state. These natural landscapes have been almost entirely degraded and converted to farming and / or residential homestead areas.
When Europeans settled in Minnesota in the mid-1800s, they suppressed fire over large parts of the state. Most of the suppression was a result of converting lands to agricultural crops, pastures, and roads. Europeans brought over buckthorn to plant as ornamental hedges or to use as property fences. Buckthorn’ s leaves emerge early in the spring and remain until late into the fall, creating
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dense shade. Buckthorn out-competes many native plants for nutrients, light, and moisture. According to the Minnesota Department of Natural Resources, buckthorn can grow up to 25 feet high in either shrub form or as a single-trunk tree.
Tyler Carlson is the Forestry and Prescribed Fire Lead for the Sustainable Farming Association( SFA) of Minnesota. His background is in regenerative grazing and agroforestry( the practice of growing trees into crop fields and animal pastures). He was first exposed to the principles of agroforestry while studying restoration ecology and sustainable agriculture at the University of Minnesota where he received his Bachelor of Science degree. Carlson went on to complete the Agroforestry Academy program through the University of Missouri Center for Agroforestry.
Leading the silvopasture programming
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at SFA since 2020, Carlson is currently writing a grant on silvopasture by subtraction. Silvopasture is actively managing land by intentionally combining trees, forage( grasses and plants), and livestock on the same piece of land. Silvopasture by subtraction is removing some trees from existing woodland to let sunlight in so grass can grow for more cattle grazing. Carlson said,“ Our aim is to utilize silvopasture as a means to restore or reclaim some of these landscapes on private lands. In the course of that work, buckthorn, a non-native invasive shrub, has become a big part of our work as many of these savannahs and woodlands have been invaded by or will soon be invaded by buckthorn.”
It is the perfect condition for buckthorn to grow and develop and dominate the sites, Carlson said.
“ You end up with a few oak trees, some other native trees which have grown up
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