DETROIT—On a bright, breezy morning this summer, Orin Gelderloos, a biologist, climbs a steep hillside through a thicket of trees, flowers, and tall grass. He notes the precipitous ravines and admires the elevated view in the otherwise flat terrain.
Then he asks, "Has anyone ever checked around here for hazardous material?"
His concern is prompted by a rusty steel barrel near the bottom of the slope. Bricks and cement shards also protrude from the ground.
This is not a hill in Michigan's pristine North Woods; it is an illegal dump site at the edge of an abandoned neighborhood along Huber Avenue in the middle of Detroit. The discarded soil and construction materials have morphed into a mound covered with vegetation. It rises two stories and sprawls across an area the size of two baseball infields. Some trees are 30 feet (9 meters) tall.
"This is a very, very interesting combination of things," says Gelderloos, a professor of biology and environmental studies at the University of Michigan-Dearborn. He identifies nine species of plants and six species of trees growing from the mound. "It's a fascinating area."
The Huber Avenue mound is among the biggest of hundreds of dump sites across Detroit reverting to nature. Some are the size of a few automobiles; others are as small as a pup tent. A new two-story pile of dirt on the west side is just starting to turn green. Older ones are resplendent with Queen Anne's Lace, thistle, goldenrod, grass, and weeds. The oldest are sprouting cottonwoods, silver maples, and other trees.
Virtually all the mounds are byproducts of the bankrupt city's epic abandonment as its population fell from about two million residents in the early 1950s to about 688,000 today. (Related: "In Detroit, Water Crisis Symbolizes Decline, and Hope.")
For years scofflaws have avoided fees at commercial dumps by unloading such heavy materials as cement, soil, metal, and wood on vacant patches where homes and businesses once stood. In Detroit, a sprawling city of 139 square miles (360 square kilometers), this empty landscape is estimated to cover as much as 40 square miles (104 square kilometers), which is more space than Lansing, the state capital, occupies.
Nature Creeps Back
The city's shorthanded police force, busy with serious crime, has little time to patrol these areas or enforce laws against illegal dumping, and similarly strapped public works crews have been unable to keep up with the deposits. So the piles sit, sometimes for a decade or more, and nature gradually reasserts itself, covering the clutter with a verdant facade.
Gelderloos, whose interests include urban vegetation and "ruderal species," or plants that are the first to colonize disturbed lands, said that only certain species will grow on a site that has been disrupted by dumping, which alters the soil's makeup. Debris such as concrete, for example, contains limestone, which increases the soil's alkalinity.
"You can't go planting petunias here," he says. "The soil and water aren't great. These are hardy, hardy plants."
The mounds add to Detroit's unruly and lush appearance in summer, which is flamboyantly emphasized by trees growing on the roofs and inside of abandoned buildings. Camilo José Vergara, an internationally known sociologist and photographer who has chronicled the decline of Detroit and other cities, has called this transformation "a veil of vegetation creeping across the city."
There is no official estimate of the number of mounds in Detroit, partly because few city officials appear to have noticed them.
Even though the mounds have made their mark on the city's topography for more than a decade, in many ways they are hiding in plain sight. Many are in sparsely occupied neighborhoods rarely visited by outsiders. Illegal dumping is less risky in such isolated spots.
Ron Brundidge, director of the city's Department of Public Works, said he couldn't recall seeing any. But Brundidge knows all too well the city's problem with fresh illegal dump sites that nature hasn't yet covered, and he said Mayor Mike Duggan, who took office in January, has made blight removal a priority.
"For the past four months, we have [had] 40 to 50 workers targeting illegal dumpsites and hauling away an average of 600 tons of debris a week," Brundidge says.
The mounds, though, are a source of fascination for some people whose jobs or avocations take them to distant corners of Detroit.
I discovered them in 2007, when I drove all of the approximately 2,100 streets in the city while working on a project for the Detroit Free Press. I saw as many as ten mounds each week during the 4½ months that I drove around the city, but I didn't realize they were dump sites until I noticed new ones with debris still visible under the slowly spreading vegetation.
"We've seen them all over the city," says Dean Hay, an arborist who serves as director of green infrastructure for The Greening of Detroit, a nonprofit that since 1989 has planted trees and worked to improve the city's open spaces and urban agriculture. "My interpretation of this phenomenon is that most of the piles contain biodegradable items or items that 'capture' soil-less airborne particles along the surface of the pile. When enough medium is collected as a top layer, seeds begin to be trapped, [then] germinate and create a green cover."
Scott Hocking, a well-known Detroit artist who uses the city's landscape and artifacts in his work, has investigated the mounds for years. "This is really a big interest of mine," he says. "I know where these things are, all over the city. And they're everywhere."
Hocking has paid special attention to the neighborhood around the Huber Avenue mound. It's 189 wild and spooky acres of lavish vegetation interspersed with piles of tires, furniture, and other trash. In years past, pleasure boats have even been dumped there.
This urban detritus occupies the grid of streets and alleys from what was once a densely packed working-class neighborhood, but now all the buildings are gone. Hocking calls the area "The Zone."
"There are a ton of illegal dumps-turned-mounds throughout The Zone," he says. "Tons of smaller ones have appeared along the blocked roadways over the years."
As Detroit winds its way through federal bankruptcy court to resolve its severe financial problems, a number of groups are looking to the future of a rejuvenated Detroit and devising strategies for the city's abandoned land—even leaving some of it empty.
Hay, the arborist, says the city must find ways to stop illegal dumping, but it might also think about creative ways to use the mounds. "We see vacant land as an asset," he says. "You could use the mounds to perhaps trap stormwater or to give a little more free form to these areas. And you could do it without spending a lot of money."