If you’ve got photos, please send them in. I have about a week’s worth now, but in a week they’ll be gone. Thanks!
Today’s photos are contributed by reader Gregory Zonerowich, who directs the graduate program in ent0mology at Kansas State University in Manhattan, Kansas. This series shows a controlled burn on the prairie. Gregory’s notes are indented, and you can enlarge the photos by clicking on them.
These are all taken at the Konza Prairie Biological Station just a few miles south of Manhattan, KS. The station is 8,600 acres of tallgrass prairie and is one of the original NSF Long-Term Ecological Research sites. Only about 2-3% of tallgrass prairie remains in the US.
The station maintains a herd of bison (Bison bison) to study the effects of native grazers. The lighting was not very good for this photo but the bull had such a regal pose.
Controlled burns are a common land management practice in this region and are necessary to preserve the prairie. We start at the upwind side of a watershed with two crews moving in opposite directions. Here a torcher widens the initial buffer along the edge of burn. There may hundreds of acres involving more than one watershed during a burn. Often the two crews are out of sight so we use radios to monitor each other’s progress. Communication and coordination can be critical given the direction of the wind and the natural twists and turns of the watersheds.
Backfires are low intensity and move very slowly against the wind, sometimes only about a foot per minute.
A nice comparison of a backfire and a head fire. The backfire is low and moves slowly against the wind, the head fire moves with the wind as a tall, hot, and fast wall of flame.
Universities and government agencies such as the EPA and US Forest Service conduct various studies at the station, including fire behavior and the gases and microbes found in smoke. Here a drone is taking smoke samples.
After the two burn crews meet at the downwind side of the watershed and the watershed has been ringed by fire, the head fire moving with the wind creates a surprisingly noisy maelstrom of smoke and flames. I used to wonder how people out in the open could be caught and consumed by wildfires, but I’ve seen many head fires I could not outrun.
It’s pretty easy to get dramatic photos while out on a prairie burn.
The result of a controlled burn, blackened earth that will soon green up with new grass after a spring rain. The burns expose the rocky soil and show why much of this prairie was spared from the plow.
Two watersheds are burned during the summer of every other year, hence the very dense smoke with the sun peeking through. “Bambi” is a military surplus vehicle equipped with a large water tank to refill the 300-gallon water tanks the burn crews have on their vehicles.
I liked the contrast between the black burned prairie, the tan unburned area, and the blue sky.
I’m always fascinated by the physics that produce smoke tornados, or “ashnados”. Sometimes they are just a few inches wide at the base but they also can be several feet wide at the base. These can dangerous because they might pick up hot ash or embers and drop them into an unburned watershed, creating a wildfire. For scale, the red truck is a Ford F-350 dually with a 300-gallon water tank on the back.
This tall white ashnado was right behind the site manager.
The station has a number of creeks and seeps. They run in most years but will dry up during a drought.
For folks who may be interested in controlled burns:
Nice drone view of a prairie burn:
Why burns benefit the prairie:
What a fascinating post! Thank you for sharing that.
I grew up near a patch of well maintained natural prairie, and it was a great teacher to me. Some years ago I had visited it again, and apparently under new management, the regular controlled burns had been stopped. It was well on its way to becoming forest, just like any other forest in the area.
What a great post! I was wondering how they did controlled burns.
Thanks!
Fabulous stills and videos of the fires and ashnados. Since it looks like you work on controlled burns, I’ve always had a question about what happens to the small wildlife (rabbits, rodents, reptiles, non-flying insects, etc.) potentially trapped in the center. Do they all have sufficient escape holes and air in those holes to ride out the fires below ground? Even if they do, once they emerge it seems like they would suffer a lack of food for at least several weeks and serious exposure to predators. Someone must have investigated this. Any good references? Thanks.
Those are great questions. The watersheds with bison often have shorter, less dense vegetation due to grazing, or many areas where the grass is grazed down enough it won’t sustain any flames. Thus, they usually do not get the fast, tall wall of head fire like an ungrazed watershed gets. The bison just wander out of the way of the fire. They do know that after an area is burned the new and nutritious grass will appear soon, often in 7-10 days if it rains. Deer, rabbits, coyotes, and the occasional elk are fast enough to get through a low backfire without harm or get through an area that does not yet have fire on it. There are are instances where an adjacent watershed was recently burned so we don’t have to light along that border, which leaves an escape route for animals. I’ve been helping out since 2001 and occasionally we will find a snake or lizard that got caught in the flames. I’ve also saved a few horned toads. Most of the watersheds are burned in March and April before a lot of insects are out. Those that overwinter in the soil or under rocks are safe, but any exposed pupae or larvae won’t make it. There is a fair amount of literature on the effects of fire on insects. It’s hard to make general statements since fire can affect each species in a different way.
Thank you for the response!
Thank you – I enjoyed learning about your work. The photo with the tree and burned/unburned areas is beautiful.
Ditto to both of Janet’s comments.
Interesting!
A really informative photo essay! I used to be on the crew at my college but got too old and then retired. Most of our prescribed burns were in oak forests, but we had one small prairie. I miss the experience. Thanks!
Ashnado? That’s new to me. This was a very fascinating post. Thank you very much for taking the time putting it together and explaining what is going on. Great videos as well.
Appreciate this specific, up close look at an important process – counterintuitive!