In August of 1834, a German by the name of Karl Neidhard rode through the decade-old city of Ann Arbor on his way to Pleasant Lake. The sparse terrain intrigued him, and he would later note in his diary how “the monotonous landscape ceases near Ann Arbor; and here the country becomes more interesting … the dense forests disappear and lakes surrounded by pretty hills and park-like woods, which the Americans call ‘oak openings’ meet the traveler’s eye.”
182 years later, at an informational meeting for Ann Arbor’s controlled burn program, David Borneman, the director of Ann Arbor’s Natural Area Preservation department, began by having audience members read Neidhard’s account out loud. As they munched on complimentary coffee and organic cookies, he then launched into a sermon-like explaination of controlled burns.
“If we’re going to restore our ecosystems, let’s get a firm idea of what we’re restoring to,” Borneman said.
If you overheard the terms “invasive” or “non-native” nowadays, you might assume that someone was talking about the current presidential election. But in Ann Arbor, and the United States as a whole, these terms are better applied to plants. According to the United States Department of Agriculture, invasive species “are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm.” This harm is both aesthetic and ecological. The National Wildlife Federation estimates that 42% of threatened or endangered species in America are in their state because of invasive species.
In Ann Arbor, the threat is primarily aesthetic. With over 100 invasive species present in city parks, including commonly seen greenery like Oriental Bittersweet and European Buckthorn, many of them are overgrown. Unusual for a city, Ann Arbor has combatted invasive species and overgrowth by conducting controlled burns since 1993. By torching a plot of public land, officials hope to clear away invasive species and dead plant life, allowing fire-resistant native species to flourish. Although burns are conducted on public land, coordinators receive complaints from residents worried about smoke inhalation and potential property damage.
“Even though we’ve been doing this for 20 years, when new people move in, they’re often concerned about having a fire next to their fence,” said Tina Stephens, an outreach coordinator for the Ann Arbor City Government.
Beyond safety concerns, though, coordinators must ask a question with no real answer: what is Ann Arbor supposed to look like?
People have been setting fires in Ann Arbor for over 5,000 years. Native Americans used flames to drive out game, clear away dead plant life and fertilize the soil. Since European colonization, the landscape has gradually been overrun by excessive non-native species and dead detritus. In Ann Arbor, this detritus incubates icy ground, preventing native flowers from blooming. In dryer areas, like Oklahoma or Idaho, excess dry material can equal forest fires.
“The fires we have today are the result of years of Smokey the Bear saying all fires are bad,” Bornemann said in an interview. “It took us too many decades to learn that it’s not if, but when [forest fires will occur].”
In Oklahoma, where the majority of American forest fires are currently burning, government agencies will, ironically, sometimes torch as many as 10,000 acres at a time in order to prevent forest fires several times that size. In Ann Arbor, the scale is much smaller — five to fifteen acres are burned on a normal day, and the burns are mostly cosmetic. However, the proximity to residential areas provides its own set of difficulties, one of the reasons many cities are reluctant to perform them. In April 2015, for example, the Los Angeles County Parks Department tried to perform a small controlled burn, but strong winds spread the fires over 70 acres, destroying a car and forcing the evacuation of a middle school.
To prevent episodes like this, Ann Arbor burns can be conducted on weekdays, preferably during the afternoon when people are out of their houses. Care is also taken to ensure that no homeless encampments are in the path of the fire. They’re only decided upon the morning of, because the burns are so weather-dependent; above fifty-percent relative humidity or strong winds will make for weak, directionless fires. The actual burn is conducted in several steps. First, a “backing fire” is formed at one end of the land plot, to burn away fuel and form a fireproof barrier. Next, volunteers, clad in a fireproof fabric called nomex, use drip-torches spread burning diesel along the perimeter, forming a “flanking fire.” A “head fire” is then lit at the end opposite the “break,” which gradually burns the length of the plot. Finally, volunteers move in with water sprayers and hand tools to do a “mop up,” removing any remaining sparks or embers. While the fire burns, other volunteers act as smoke monitors, gauging how much smoke the fire is producing. Smoke is a far bigger danger than fire to everyone nearby — smoke particles can travel hundreds of yards and be as small as a grain of pollen.
No matter how well the fire is contained, it will inevitably maim or kill wildlife. To prevent any undue harm, the burn team employs both a herpetologist and an ornithologist to examine each site and assess the cost-benefit ratio to the animals living in it.
“Of course, the short-term impact could harm an animal,” said Patrick Terry, the staff herpetologist. “But the burns are a natural succession for the environment.”
Borneman had a similarly holistic attitude.
“If we want butterflies here long-term, we might end up killing some of them in our fires,” he said
Be it about reptiles, birds, plants, or simply scenery, this seems to be the guiding philosophy for the Natural Area Preservation team. In an ecosystem which has been altered by humans for so long, the definition of “natural” is now in human hands. Ann Arbor, and its controlled-burn team, apply this definition to the ultimate human ecosystem: the city.