Prescribed burns ignite Michigan wildlife habitat growth
May 8, 2014
Spring is fire season in Michigan. The retreating snow and ice of winter leave behind a landscape of dead vegetation that serves as prime fuel for wildfires. At the same time, the vegetation also provides fuel for fires that state land managers want to see - fires that thin out overgrown vegetation or prepare the landscape for planting.
Employees within the Department of Natural Resources' Forest Resources Division (FRD) are responsible for both, putting out wildfires and igniting prescribed burns on land that can be managed using fire.
On a recent mid-April morning, Dan Laux, a fire management specialist with FRD, assembled his crew of 12 to burn about an eighth of Verona State Game Area in Huron County. The project, which would take nearly three long days to complete, is part of an ongoing effort to improve pheasant habitat as part of the Michigan Pheasant Restoration Initiative.
According to Laux, the burns were conducted with a three-step process. First, a firebreak was created with a plow around the perimeter of the area to be burned. Then, DNR fire officers - as well as DNR personnel from other divisions who have been trained to work a fire line - created a "black line" by setting fire to the area immediately inside the firebreak.
"You're widening your safety buffer so when the hotter fire gets to that part of the field, there's less chance of a problem," Laux said.
Once the black lines have been established the crew begins burning the field, using drip torches - containers with a mixture of three parts diesel fuel to one part gasoline - to ignite the vegetation. Burns are started on the downwind side of the field to prevent the fire from getting out of control.
The prescribed burns at Verona were of two varieties, explained DNR wildlife biologist Don Bonnette, who oversees the area. Some are simply "maintenance burns" to thin out the undesirable vegetation that has grown on the area. Other areas were burned to prepare the ground for seeding with what Bonnette calls "the Big Four" - a mixture of big bluestem, little bluestem, Indian and switch grasses - for pheasant habitat.
"You want to burn as much as you can when you're going to replant," Bonnette said. "No-till seeders can get plugged up by the grass."
While Laux and his crew were working at Verona, another crew assembled at Fish Point Wildlife Management Area about 25 miles away in neighboring Tuscola County. The burn boss - Lee Osterland, another FRD fire management specialist - had a crew of 13 on hand to burn about 280 acres of marsh in the area's refuge. The marsh, long overgrown with cattails and phragmites (an invasive grass), has been scheduled for burns since 2008, but conditions were never right.
The area hadn't been burned in 25 years, and the vegetation was choking out the wetlands. The burn had originally been planned for winter, and the DNR Wildlife Division crew at Fish Point had sprayed the phragmites and begun pumping water from the wetland in December in preparation for it. Excessive snow and ice made that impossible. The fire wouldn't burn down to the root stock of the vegetation with the snow cover, and the vegetation would just come back in the spring.
Because of residences to the north and adjacent highways, the crew needed a north-to-northwest wind to burn safely without sending too much smoke in the wrong directions, Osterland said.
"We don't want to impact the local residents or the highways," he said. "Years ago, the only way we could do this was in the winter because we didn't have the amphibious equipment we have now."
Site preparation was similar to those at Verona, but the crew did not need to cut a firebreak as ditches, dikes, roads and open water ringed the perimeter. The crew created black lines along the perimeter - paying special attention to areas around the utility poles that run through the marsh - before setting the larger fire.
The prescribed burn was accomplished in a matter of hours and achieved its objectives, Osterland said.
Fire is a common tool for wetlands management, said Joe Robison, the wildlife biologist who oversees the DNR managed waterfowl areas of southern Michigan.
"Burning is part of our management to eradicate phragmites," he explained. "We typically spray it, then burn it to get rid of it, then put water on top of it to deter it from growing back. Then we try to keep the water level high enough to keep it from coming back and allow the native plant species back in.
"With cattail marshes, sometimes they become a single monoculture," Robison continued. "It becomes solid cattails. We try to manage them as hemi-marshes - half open water and half vegetation. That's a great mix for waterfowl for their whole cycles - staging, food availability, nesting and brood-raising."
Every prescribed burn is different, Robison said.
"There's no cookbook recipe," he said. "The habitat manager has to look at it and make a decision on what he's trying to accomplish."
It's been a busy season for FRD fire crews as the division has completed some 54 burns through late April, more than were conducted all of last year. Wildlife Division has more on its wish list, but prescribed burns are time, equipment and labor intensive.
"This is a direct result of us being able to direct $500,000 toward habitat improvement this year," said Wildlife Division Chief Russ Mason. "And that's a direct result of the change in the license fee structure."
Though spring will soon shift into summer, FRD is by no means finished burning for the season.
"We've got a lot of burns to do yet," Osterland said. "We do a lot of burns in the spring - a lot of them call for the burn prior to growing season. But you have different mixtures of vegetation with cool-season grasses and warm-season grasses responding differently. Sometimes we'll burn in the summer so we'll get a little bit different kind of vegetation coming up.
"We conducted late burns in June last year in elk habitat to set back brush."
Similarly, FRD will be conducting prescribed burns for its own purposes.
"We often conduct slash fires (from timber sales) during the summer as the debris has dried out and the surrounding greenery makes it easier to control the fire," Osterland said. "That makes it easier to get the equipment in for planting an area."
For more information on prescribed burning and the DNR's Fire Program, visit www.michigan.gov/firemanagement.