CHICAGO (CBS) — Plumes of smoke have been rising this week from prairies at Fermilab, the Morton Arboretum and other open spaces which naturalists are trying to keep open throughout the Chicago area.

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Manager of Collections Chris Bachtel at the Morton Arboretum says fire was a natural part of life.

“The fire is part of the natural ecosystem of these things and that is why they call Illinois the prairie state, over 95 percent of the state was prairies where they would be burned periodically either by the Native Americans or by lightning starts,” said Bachtel.

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Chris Bachtel says Native Americans used fire to fertilize the soil and promote vigorous growth of diverse plant communities which attracted food in the form of wildlife.

Steve Apfelbaum, the founder of Applied Ecological Services, says fire is and always has been a vital part of prairie life.

“Several of the aggressive plant species will become dominant and suppress the diversity of many of the smaller-growing, shorter stature plant species will disappear,” said Apfelbaum.

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Apfelbaum, whose Applied Ecological Services builds and restores prairies on devastated lands, says this is the time of year for prairie burning when old growth has dried out and can be burnt off without injuring the coming year’s crop of prairie plants.