My first prescribed burn(s)

I've been volunteering with the forest preserves near my hometown of Chicago for a little less than two years. The work we do varies with the season. In the winter, we're cutting and burning buckthorn and other invasive/over-abundant trees and shrubs. Spring, we pull invasives like garlic mustard, dame's rocket, and sweet clover. Summer, we collect seeds to distribute more widely in our preserve and others in the area. And in the fall, we continue with seed collecting, seed cleaning, and eventually switch back to cutting and burning. I love all of this work— okay, pulling garlic mustard gets old pretty fast— and find it immensely rewarding.

But this fall, I had the chance to train to be a volunteer on prescribed burn crews in the area. It was a weekend well spent. I got to join three burns during the short fall burn season, and they were awesome.

Admittedly, I look like a dork... but it's cool, I promise!

A lot of people I've talked to assume that prescribed burning in the Midwest has the same function as it does out West: it's done to remove dead litter that can build up over years, contributing to massive wildfires. I can't blame anyone for making that assumption, since it's all we hear about on the news in the summer, but in Illinois most of the remaining natural areas are so scattered and small that rogue wildfires generally aren't a huge concern.

But historically, much of the Midwest would have experienced frequent fires. The major pre-colonial ecosystems in much of the heartland of the U.S.— prairie and savanna— have adapted to fire over thousands of years. In addition to natural burns caused by lightning strikes, Native Americans intentionally used fire to keep land open for hunting, to herd animals such as bison, and to encourage the growth of specific crops, among other things ^[1] .

But then came the American settlers, and increasing development... I bet you can guess where this is going.

Backpack sprayers to make sure the fire didn't spread to some highly-flammable cattails on the right

Fire was generally suppressed during the 20th century. You can imagine why. If there weren't reliable methods for controlling a blaze, I probably wouldn't have wanted the land near my house to burn either. It took a long time for people to intuit that when an ecosystem is adjusted to some condition (like fire) over a very long term, maintaining that condition is probably best for the diversity of the ecosystem. Regular burns are the main thing preventing trees from invading a prairie or darkening a savanna into a woodland, and crowding out those species that need the extra light.

But fires look so damn destructive! How could it be good for plants and trees to get burnt to a crisp twice a year?

Well, as hinted at earlier, species native to fire-prone areas are... shocker... kind of used to it. A prime example is the bur oak: a beautiful, stately tree . Its thick, corky bark helps protect it from burns; while young trees might not survive a ground fire , mature ones will generally do just fine in a lower-intensity blaze. And this gives it a competitive edge in its ecosystem: other, faster-growing native trees like shagbark hickory are more likely to get killed during a burn, leaving more light for the bur oaks.

See?? The trees are fine!

And there are plenty more examples. Perennial prairie plants start their growth from buds below the soil ^[2] , meaning they aren't killed if their above-ground components are burned up— just set back a bit. (And if the burn is in the late fall, they probably aren't even set back at all since they would've had to grow from the ground up in the spring anyway.) Some species, like Bicknell's geranium, thrive in the wake of a fire and won't germinate until another such disturbance reduces the nearby competition.

A burned-off section, with more unburned big bluestem and other fuel to the left

Smoldering prairie after the headfire ran across the preserve

But this is all to say that fire is, on the whole, good for prairies and savannas. It's an effective land management tool for maintaining the biodiversity of our oh-so-precious natural areas. And it's an awesome spectacle.