Fire and flowers return to the prairie
Around the US, native ecosystems are being restored because of their environmental benefits.
Every morning throughout April and early May, a cadre of highly trained men and women meets as the sun rises over suburban Minneapolis and St. Paul to decide whose lawn to ignite.
"You can't plan ahead," says Ron Bowen. "You have to take them one at a time and pick the ones that you can burn today with the least problems. You have to be spontaneous. It's a matter of wind, temperature, and moisture."
Mr. Bowen owns Prairie Restorations of Princeton, Minn. For years he's been involved in planting and managing large prairie ecosystems for clients such as the Nature Conservancy and state agencies. More recently he's turned to suburbia - turning expanses of lawn into gardens of more ecologically sensitive native plants.
"On the outer fringe of metropolitan areas there are more people that have one-to-five-acre lots and are mowing edge to edge," he laments. "On even a one-acre plot it would work well to have 50 to 75 percent in something other than mowed [grass]. That could be dry prairie, open woodland and native grasses, or a wetland with native grasses."
Bowen, whose company has established these kinds of plantings as far afield as Maryland, grew up on the fringes of suburban St. Paul. He watched as, like a prairie fire, civilization swept out from the city and the wild places he loved were covered in pavement or grass.
"I saw those woods get cut down and the streams get put into culverts and fields turned into housing lots. I felt there was something wrong," Bowen remembers.
His passion has placed him smack in the middle of the relatively new field of restoration ecology.
Restoration ecologists study how to successfully repair ecosystems damaged or destroyed by mining, stream erosion, or industrial brown fields.
That's not an easy task. There are dozens of different prairie ecosystems, and the species diversity in just one can be greater than a complex forest ecosystem.
"On a good-quality native prairie remnant of one acre there's about 250 species," Bowen says.
Each prairie ecosystem - whether a wooded savannah, a dry upland, or a wetland - has a different species mix. Bowen sees the work of designing a planting as being something like an artist choosing just the right colors for a painting.
"A residential site can have a number of different conditions from wet to dry or from woodland to full sun, so if you were really fine-tuning it you'd have a minimum of a couple different seed mixes," he says. "Your short list of grasses might include little bluestem and sideoats grama. If you get into the lower areas or more on the property's periphery, where you can do a little design work with height, you put big bluestem, Indian grass, maybe a little bit of switch grass if [the site is] wet. Then you'd add a whole complement of flowers like butterfly weed, black-eyed Susans, common oxeye [daisy], and in a wet area, gentian and iris."
Across the country, other companies are also offering homeowners the option of growing something other than turf grass around their homes.
In California, where grasslands and fire were a major part of the indigenous ecosystems, Elkhorn Native Plant Nursery of Moss Landing, Calif., works with customers to re-create what ecologist Jean Ferreira calls coastal prairies.
"I'm on a ranch that's 1,100 acres, and I would imagine that probably 800 acres was originally native coastal prairie," she says.
Although she does big projects, Ms. Ferreira perks up when she talks about the half-dozen small residential plantings she helped design and plant last season. The one she put in her yard is typical.
"It is about 20 feet by 10 feet," she says. "I have foothill sedges all around the edges and tufted hair grass inside of that and in the very center taller species like purple needle grass. Most of our native grasses are bunch grasses so I plant flowers in between. I didn't have to mow it, and it breaks the lawn's flat monotony."
Although all of the coastal prairie species evolved to thrive on fire, Ferreira hand-weeded her prairie garden. Elkhorn does use fire to manage grasslands, but not as extensively as Prairie Restorations.
Next to the beauty of the prairie flowers and grasses, fire is the most dramatic part of managing retro-lawns. For the pyrotechnicians who work for Bowen - they prefer being called restorationists - managing fire is like walking the dog.
Using back sprayers filled with water, backpack drip torches that lay down blobs of flaming kerosene, and the wind as tools, they can make fire turn corners, burn circles around trees, and almost roll over.
Rather than just torching a yard, Bowen's crew first lights little fires that establish fire barriers of ash around trees and buildings their clients don't want turned to ash. Once those are protected with a circle of black, they'll release the whole yard to flame. It'll all be over within less time than it would take to mow it.
But why fire?
Fire is a critical event in natural prairie ecosystems. It is a tonic to rejuvenate grasses and flowers. On a planted prairie a controlled conflagration should happen every three years.
"We had a pasture of native red fescue that we had established as a demonstration," says Elkhorn's Ferreira. "It was patchy and not filling in. Then we burned it, and it filled in nicely." She also uses fire to combat weeds and exotic species.
Fire works well only on plantings that are three or more years old. Prior to that there isn't enough fuel to support flames to cleanse the prairie of weeds and encourage the native species.
Burning a lawn usually costs less than mowing. State Farm Insurance in Woodbury, Minn., reports that maintaining its 45-acre prairie costs an eighth of the cost to manage a similar turf area. Large plantings have economies of scale but, Bowen estimates, the outlay for a residential prairie can will be less than half the cost of a sodded and irrigated lawn.
Native prairie grasses are more adapted to drought than are the grasses used in most lawns. Purple needle grass, for instance, has six-foot-deep roots. Commonly planted lawn grasses, such as bluegrass, have roots a few inches long. Drought-resistant lawns that require no watering can help prevent water shortages and rationing in rapidly expanding suburbs, according to Steve Kernik, an environmental planner for the city of Woodbury, Minn., a suburb of St. Paul.
Woodbury has an ordinance that encourages prairie plantings because, in part, they use less water. City officials also appreciate the controlled use of fire.
"We really like this approach," says assistant fire chief Rob Miller. "If they didn't do it now in a managed way, we might have to be up here [later] to put out a much bigger fire."
"When you burn in suburbia you need a permit, and ... the right equipment," Bowen says. "In suburban areas, and even in urban areas, the physical danger from the fire is minimal. It's usually surrounded by good fire breaks like mowed grass, blacktop, and sidewalks.
"But there are two problems," he adds. "Neighbors and street traffic. My biggest fear is that smoke will cross the road and there'll be an accident."
That's why, each morning this spring, Bowen and his crew will wait to see which way the wind is blowing before they decide whose lawn to ignite.