Why Prescribed Burns are Needed

By Steve Weisman

Each spring we can see clouds of smoke billowing up from both state wildlife areas and on private tracts of grassland all across northwest Iowa. Oftentimes I will hear people questioning or complaining about the fire eating up the spent grasses from the previous year or even several years.

For me however, it is a welcome sign. These burns, known as prescribed burns, are done by landowners (both public and private) to maintain the health of the grasslands, often tall grass prairie, by helping manage weeds and helping to eliminate volunteer trees and invasive plants. The prescribed burns also help restore nutrients and improve the quality of the land. On private Conservation Reserve Program (CRP) lands, the prescribed burns are known as mid-contract burns.

Sometimes, people really get upset with these prescribed burns and ask, “Why would you want to get rid of those trees? Why not leave things alone?” The answer is kind of complicated. Yes, we like to plant trees and see wooded areas develop. However, prairie is prairie, and it is meant to be prairie.

Historically speaking
Take a look at the early days when the Europeans crossed our country. They found miles and miles of prairie described by some as an ocean of tall grass prairie. Yes, it was solid grass and had been that way for years and years with no trees or shrubs. In addition to grasses such as big bluestem, little bluestem and Indian grass, the prairie ecosystem included a host of wildflowers. From the early spring through the growing season, different forbes would open up in bloom. Historians note that Iowa was in the very heart of the tall grass prairie and that 75 to 80 percent of the state was once covered in prairie. The Iowa Natural Heritage Foundation estimates that this was the largest percentage in the nation.

Yes, there were trees, but they were mostly found along creeks and streams. Between the thick stand of native tall grasses, the ever so often prairie burn started by a lightning strike and the grazing of the buffalo, the invasive saplings didn’t stand much of a chance.
So, simply put prairie is prairie! Doug Harr, president of Iowa Audubon and former State Coordinator of the Iowa DNR’s Wildlife Diversity Program, visited with me a few years ago about this topic. He said, ““Trees do belong in some places, and they certainly don’t belong in others.” The first question we must ask ourselves is this: “What is this parcel of land supposed to be and are we trying to return it to what it was before humans broke it up and turned it into agriculture land?”

Back to today
Today is a far cry from the tall grass prairie days. Most of that land has become some of the richest crop producing land in the world. Today, historians say less than 0.1 percent of the original tallgrass prairie is left in Iowa. Instead, there are managed remnants and tracts of CRP land that have been planted into a mix of tallgrass prairie and forbes. To manage these acres, prescribed burns are part of the management plan.

However, it’s not as simple as just going out and starting a fire. On state-owned land, DNR crews are trained to safely orchestrate a prescribed burn, there are professionally trained private companies and also area fire departments that have been trained in safely performing a prescribed burn.

While the burns rejuvenate the grasses, they also work on destroying small volunteer invasive trees and shrubs. Managers have found if the invasive are allowed to grow, over time they will begin to shade and crowd out the prairie. The volunteer trees that show up on this prairie ground are invasives: ash, willows, cottonwood trees, cedar trees, mulberry bushes, hackberry trees, dogwood shrubs…and, yes, even tame grasses like brome These cool-season grasses which grow quickly in the early spring and can be set back by burns, allowing the summer-flowering native prairie grasses to flourish. They all need to be controlled. If left alone, they will grow and expand until you don’t really know what you have: prairie or woodland or just a hodgepodge that isn’t really worth much of anything.

Many of these lands also have wetlands and sloughs. It is here that the willows really take off. They like the wet soil, and in a few years many sloughs are lined by willows that can soon overtake the slough. What is neat about the burn is that everything is clear except for any larger saplings. So, it becomes easy to walk around and cut down any of those larger saplings. That, however, must be done or the invasive trees will continue to grow.

A personal battle
For over 32 years, my wife and I have owned a farm near Graettinger, IA that is really hilly. About 60 percent of it should never be cropped. So, we have worked with the USDA and NRCS to put in several conservation practices. Let me tell you just how aggressive these invasive trees and shrubs can be. If I had left them alone, never did a mid-contract prescribed burn and never treated those invasives that survived the burns, I would now have one huge mess of volunteer tress not worth anything. It would no longer be a prairie, and it certainly would not be a desirable woodland or forest. It would simply be a mess.

We have four small wetlands on the property, and in the fall of 2019, it was time to renew the contract with the USDA. Three of the wetlands I had done a good job of keeping the sloughs free of trees. Willows are always popping up; they love the wet soil and moisture of the pond. On three of the ponds I had battled the willows and through cutting and herbicides (safe for grasses and waterways) had been able to stay ahead of them. Each year I battled the willows and found a good rule of thumb: eradicate them when they’re small, and you win.

Wait too long, and it’s time for big time reinforcements.

Unfortunately, one slough I let get away from me. I thought to myself, “Oh well. What the heck. Let it go!” However, the USDA informed me early last fall that if I wanted to renew the contract, I had to get rid of those willows. They were all sizes ranging from a half inch in diameter to up to 3-4 inches in diameter. What a mess. It looked like a willow cornfield. I had a friend lined up to take a chainsaw to the larger ones, but cutting them all down by hand would have taken days.

Luckily, I have some of the best neighbors around. I talked to one, and he brought his heavy-duty brush cutter in and in a matter of hours, he had cut them down to mere stubs! I then sprayed each individual stump. Next came the chainsaw to take down the bigger willows, and then I followed up with a stump application.

Then this spring I contracted the Graettinger Fire Department to burn each of those wetlands. They have done all of my prescribed burns over the years and have always done a tremendous job. Much better than doing it myself and having it get away from me and burn the neighbors’ ground.

What is neat about the burn is that everything burned off, and invasive saplings are easy to spot. So, I simply cut down any of those larger saplings and then sprayed them so they wouldn’t come back.

Now as the burned areas green up around the wetlands (clear of all saplings), it looks pristine with the glistening waters of the ponds. I am now ahead of the game, almost like starting all over again. However, I know that each year I must walk these acres and look for those little invasive trees to show up. The same holds true with the main CRP acres. I must always be on top of things and not let an invasive get away.