As much as I love the prairie in full bloom, wandering through Midewin after a controlled burn is uniquely revelatory. Last week, I had arrived for my weekly walk just in time to catch the last licks of flame flaring and crackling along Prairie Creek, consuming the head-high herbage. Fire, of course is a vital component of a healthy prairie ecosystem — especially one in recovery. Fire purges the land of invasive plant species and restores critical nutrients to the soil. Fire also reveals stories about Midewin’s rich and varied history.
Following a fire, I look forward to revisiting rocks. Erratics. Boulders that were left behind by the last of several glaciers that shaped the Grand Prairie of Illinois. One of the largest erratics at Midewin is easily viewable year-round — weighing in at 19 tons, it lies along the Henslow Trail, near to where it crosses Explosives Road.
Otherwise, it takes fire to reveal Midewin’s erratics — remembrances of its Ice Age legacy intertwined with its agricultural past. Many large erratic boulders were gathered by pioneers to clear land for plowing and to fence property lines. Walking the stone fence lines following a fire reveals and reminds us how the prairie was platted and divvied up like a giant checkerboard.
Farmers cleared smaller erratics, as well, using them as part of the concrete mix for the foundations of homes, barns and other outbuildings. The relic walls and foundations are pretty much all that’s left of the 250 or so farms acquired and razed by the United States government in order to build the Joliet Arsenal Ammunition Plant.
Controlled burns vary in their duration and intensity due to a number of factors. Many burns, as planned and managed, roll through a landscape quickly. Occasionally, especially if there is a burn pile — comprised of invasive Osage Orange trees, for instance — the fire can last longer and burn very hot. Hot enough to flake and crack and shatter stone. Erratics are metamorphic rocks, born of intense heat and pressure deep within the bowels of the earth. They migrated to the surface through eons of uplift and erosion before being carried by Ice Age glaciers from Canada. They were left behind as the glaciers retreated, there to be subjected to millennia of prairie wild fires and, now, the controlled burns of restoration.
In the midst of the prairie burn acreage, I came across the fire-kissed remains of a bur oak tree, which immediately brought to mind the Burnscapes artworks of Suze Woolf, featured in a recent exhibition at the Roger Tory Peterson Institute entitled Art that Matters to the Planet: Wild America. Woolf created these works because she is very much concerned about the world ending in fire. Fire is a hugely destructive force. It is also a force for healing, understanding and insight. Standing in the well of the tree’s hollow base, the span well wider than than the reach of my arms, the charred beauty of the heartwood invited me to reflect on the story of this ancient oak. As witness to the seasonal encampments of Potawatomi and grazing bison, its thick bark protecting it from periodic prairie fires. As witness to the permanent settlements of farmers with their domesticated livestock, and the suppression of fire. As witness to the building of the largest, most sophisticated munitions factory of its time, site of the largest accidental munitions explosion during WWII. As witness to the return of Midewin to its prairie roots, succumbing to age and returning its nutrients to the soil through the return of fire.
Love how you connect prairie burns to geology, the pioneers and even art. Well done and interesting. Having burned a northern flatwoods today with some gusting winds, an ember landed in an upper crotch of a large dead oak and became engulfed in flame in short order. Despite a high powered pump and hundreds of gallons of water, we had to chainsaw this giant to the ground so embers didn’t travel to the cedar-shake roofs of the adjoining subdivision. The oak, dead itself, now lays flat like a ancient beast too tired to stand upright — to become the host of moss and lichens and insects with Blue-spotted salamanders burrowing underneath. The life cycle continues even with death of an ancient oak. Thanks for your connective essay.
Thanks, my friend, the keeper of the flame — both metaphorical and actual. It is your goodly work in the world that is the hope for maintaining the health of our native ecosystems.