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FIRE CRUCIAL TO MANAGING MINNESOTA'S EARLY PRAIRIES
Ten thousand years ago, a 1-1/2 mile-thick sheet of ice covered the land we're living on. As the glaciers melted and receded north, the surface of the land became a sea of debris - skeletons mixed in with many types of sediment. This helps explain why southern Minnesota has such a random and helter-skelter mix of soil types.
Gradually, as the climate warmed and dried, humans began to discover that fire was an ally that discouraged trees and promoted grass. Lush stands of prairie grasses attracted elk and bison. Although prairie fires were set throughout the year, the ideal time to burn was October. Fires raged so intensely that settlers reported that they often couldn't see the horizon because the sky was completely filled with smoke.
October fires ensured that spring grass would get a one-month jump on growth, which meant that elk and bison would visit the burned area up to a month earlier than unburned prairie. And the arrival of elk and bison translated into plentiful food.
The presence of bison in burned areas kept prairie growth in check so it wouldn't burn as readily as tall-grass prairies. The next year, fires elsewhere in the prairie would stimulate a new flush of growth that attracted grazing animals. For this reason, the prairie was always moving.
These are some of the facts about prairies I learned recently from Wayne Feder, founder of Feder's Prairie Seed Company of Blue Earth. Feder's business involves managing and harvesting 150 acres of prairie flowers and grasses.
Feder says we'll never again see prairies like the original prairies because huge fires and grazing bison were important contributors to the prairie ecosystem.
Since weather patterns were never the same two years in a row, the prairie never grew in the same pattern as the previous year. One summer, the prairie might be solid purple with blazing star that had been waiting for just the perfect year to flourish. The next year, blazing star may not even appear. Prairie seeds can stay dormant for decades, just waiting for perfect conditions to sprout.
Feder says that it is very difficult for new seedlings to get established in a prairie. About the only two factors that permitted new seeds to sprout were pocket gopher activity and the powerful footsteps of bison.
Prairies also change constantly through the growing season, according to Feder. One of the first plants to appear and bloom in the spring are buttercups, followed in the weeks ahead by taller plants. Every plant simply wants its "time in the sun" for two or three weeks, Feder explains. The earliest plants to bloom in the spring are short. By fall, 6 ft. plants dominate the landscape and the once-colorful buttercups are buried at the bottom of the tangle of plant life.
The Big Woods that stretched to Mankato several hundred years ago wasn't always wooded, Feder explains. The Big Woods may have existed in this area for only 200 or 300 years and its emergence and growth may have coincided with when Native Americans got guns and gradually stopped burning the prairie. As they quit burning, the tree population exploded.
Early pioneers on the treeless prairie, according to Feder, often felt like they were living in a giant hole with a horizon at each end. Trees in our landscape give us depth perception, in other words.
Many prairie plants are drought resistant because their roots can plumb to a depth of 12 ft. These tremendous root systems keep the soil porous and loose so rainfall can soak in.
Many of southern Minnesota's earliest farms are located on hilltops and at the east end of lakes, according to Feder, because these were the location of bur oak trees. Most fires avoided hilltops and the east end of lakes due to prevailing winds. Also, the thick bark on bur oaks enabled these trees to survive prairie fires while other more thin-barked tree species were consumed by fire.
To create a prairie today, Feder says that, for the first season or two, prairie plants will spend most of their energy producing deep root systems in preparation for the periodic droughts which plague prairie climates. As a result, during the first year or two, it will appear as if annual weeds are taking over the area. Given a little light, however, by the third year, prairie plants will grow up and spread out, smothering and crowding out the weeds. The key to a successful prairie planting, therefore, is to remember to mow at regular intervals and to be patient.
The two best times to plant prairie seeds, according to Feder, are spring after the soil has warmed, and early fall until freeze-up. Feder's 12-page catalog includes guidelines on seedbed preparation, seeding, maintenance and weed control. To receive a copy, contact Feder's at 12871 - 380th Ave., Blue Earth, MN 56013, Phone 507-526-3049, Fax 507-526-3509, Email feder@bevcomm.net.
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PUTTING DOWN ROOTS:
A Delightful Blend of
Gardening Wisdom, Wit
and Whimsy
$10 + $2 for shipping
by Cliff Johnson |
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