Summer 1998

[TEXT ARCHIVE WEB-PUBLISHED MARCH 2002.
ORIGINAL PRINT PUBLICATION DATE: SUMMER 1998.]

Born to Burn

By Alex Blumberg

For most of the last few thousand years, two seas converged on the spot where Chicago now stands. One was blue, the other green. The blue sea, Lake Michigan, still pounds against the shore as it always has. But of the green one, the prairie, little remains. To see it as it once was, we have only the accounts of awestruck settlers.

"The view beggars all description," confessed W.R. Smith, traveling through the Wisconsin prairie circa 1835. Smith was not alone in his opinion. The prairie confounded every 19th century diarist, letter writer, and scribe who sought to render its grandeur in prose. Here's what the plucky Smith came up with:

"An ocean of prairie surrounds the spectator whose vision is not limited to less than 30 or 40 miles. This great sea of verdure is interspersed with delightfully varying undulations, like the vast waves of the ocean."

It must have been a stunning landscape to produce such breathless and ineffectual description. The irony is that the same settlers who preserved it for posterity in their journals plowed and grazed it nearly to oblivion. Tallgrass prairie once covered 60 percent of Illinois. Today, less than one-tenth of one percent of the landscape fits that description.

How Prairies Evolved

Mountains trap weather. They catch the prevailing wind and bind it into clouds, corral those clouds, and fatten them until they rain. To the lands leeward, mountains serve as a giant dehumidifier, draining the air of all its moisture before letting it pass. They cast what is called a rain shadow. Around 20 million years ago, give or take an eon, the two tectonic plates that met along the western half of North America collided, crumpling what had been a relatively smooth section of a relatively smooth continent into the jagged wreckage of the Rocky Mountains. It was in the rain shadow of the Rockies, five to seven million years ago, that the North American prairie probably began to evolve.

Conditions are tough in the rain shadow. It's dry. Temperatures regularly top 90 degrees F in summer and drop below zero in winter. Then there's the ungulate problem. The appearance in the fossil record of long-legged beasts with high-crowned teeth good for grinding vegetation coincides with the appearance of the first prairie plants. That's the thing about natural selection. As soon as you come on the scene, something else evolves to eat you.

The plants of the prairie, under the ruthless guidance of natural selection, adapted to these new conditions. They developed ingenious techniques to convert as much of the sun's light into energy as was possible without simultaneously overheating. These included growing their leaves small and thin to maximize both surface area and the wind's convection-cooling effects, blanketing them with hairy spindles to diffuse the sun's rays, or coating them in waxy residue to prevent water loss.

Most prairie grasses use a distinctive chemical pathway that allows them to photosynthesize quickly and use water efficiently at high temperatures. And the roots of many prairie plants burrow deep into the ground, some as far as 20 feet. This serves the dual purpose of storing water and nutrients during drought seasons and facilitating regrowth after grazing. But desert grasslands would have turned to scrub and tallgrass become forest except for one lively characteristic of this planet: lightning starts fires.

Fire

In the rain shadow, dry winds and cyclic drought turn grassland to tinder, making wildfires sparked by electrical storms a frequent occurrence. By locating their buds underground, where they are insulated from the flames, the prairie plants evolved to withstand these semi-regular torchings.

But calling the prairie fire-adapted is like calling human beings oxygen-adapted. It's not that the prairie survives in spite of fire. The prairie needs fire to survive. Fire keeps the prairie free of faster-growing, sun-stealing weeds less tolerant of immolation. Fire clears the prairie of brush and allows sunlight to penetrate to the young grasses and flowers below. In years without fire, excess organic matter accumulates, plant populations decline, and the prairie slowly chokes on its own detritus. But after a fire, the prairie produces twice as much biomass as it did the previous year.

In other ecosystems, plants' parts decay rapidly, leaving little behind to fuel a fire. Maple leaves, for example, melt quickly into the forest floor soon after falling. Prairie plants, by contrast, might as well cover themselves with dried newspaper every autumn. Their stalks persist — brittle, stiff, and highly combustible — for seasons on end. The grassland was made to burn. On flat land, in almost any climate conducive to periodic wildfires, it flourishes.

The prairie was a huge place and species varied widely depending on soil conditions, drainage, temperature, and rainfall. Even within a one-acre plot, conditions could shift from wetland fen to dry gravel prairie. Generally, though, the entire prairie biome can be divided into three distinct regions — shortgrass prairies to the west, tallgrass prairies to the east, and mixed grass prairies where they overlap. Shortgrass prairies, which dominate from the base of the Rockies to central Nebraska, consist of plants a foot or less in height and requiring less than 20 inches of precipitation a year. Further east, the rain shadow starts to blur, precipitation increases, and the tallgrass prairie rules.

The tallgrass prairie incorporates species from the shortgrass prairies to the west, but also drought and fire-adapted species that evolved on the dunes, plains, and oak or pine savannas of the Atlantic seaboard. This mix, combined with higher precipitation levels, produces taller plants, some up to six or eight feet in height.

But higher precipitation also favors non-grassland ecosystems. While the western edge of the shortgrass prairie has held stable at the Rockies for millions of years, the eastern edge of the tallgrass prairie has surged and receded in a constant battle with the hardwood forests across the Mississippi River. Ice ages, periods of warming and cooling, precipitation, and drought all contribute to the boundary's continuous redrawing. Most scientists agree that our current prairie arrived in Illinois about 8,000 years ago, when a period of dry, hot weather called the hypsothermic interval probably gave the prairie the edge it needed to roll east, forming "the prairie peninsula" through most of Illinois, and parts of Wisconsin, Indiana, and even Ohio.

According to Dr. Roger Anderson, a biologist at Illinois State University, "[M]ost ecologists believe that prairie vegetation in the eastern United States would have largely disappeared during the past 5,000 years had it not been for the nearly annual burning of the prairies by the North American Indians and the prairie fires set by lightning." Early settler accounts describe Native Americans using fire to hunt bison. Other experts theorize that pre-settlement peoples ignited the prairie with the less direct goal of resource management. Grazers such as elk, deer, and bison prefer newly burned prairie. Perhaps tribes in the region burned to maintain the productivity of their hunting grounds.

Humans have played both steward and scourge to the prairie. This ancient ecosystem's survival into the 21st century requires our mastering a new role — savior.

A Prairie Dies

There's a photograph, taken in 1907, of a meadow east of where Brookfield Zoo now stands, in Cook County, Illinois. Bluestem and June grass bow in the wind, wild onions droop petaled globes, and compass plants align their fan-like leaves to face the sun. A 1947 photograph from the same vantage point shows a different landscape: a field mottled with hawthorn thickets. The journey from the photograph of 1907 to the photograph of 1947 — from primeval wilderness to young brushland — is chronicled in a small paper published in 1959 in the American Midland Naturalist. It's titled "The Disappearance of an Area of Prairie in the Cook County, Illinois, Forest Preserve District."

What was surprising about the disappearance of this field, called the Riverside Prairie, was that it was not sacrificed on any of the typical altars: cropland, cow pasture, or strip mall. In their quest to find out why it still died, the authors of the paper, the eminent ecologist Victor E. Shelford and his colleague G.S. Winterringer, demonstrate how in the face of thunderous and widespread human impact on the environment, doing nothing to the land can be just as destructive as covering it with parking lot. One would think the prairie's demise would have started in 1870.

Developers that year gouged a wide, arching corridor of dirt out of the prairie's eastern half, the beginning of what they dreamed would be a tree-lined street in a wealthy residential neighborhood. But when the development scheme tanked at the collapse of the Chicago real estate market, the prairie surged back to reclaim the bare earth. By the time the spot was photographed in 1907, only the slightest grade in the land gave any hint the prairie ever suffered disturbance.

The prairie's downfall came later, but not when the authors say it did. They trace its decline back to 1926, when a particularly bad year for mosquitoes provoked an unfocused but intensive abatement program. The authors describe one of the measures taken this way: "[O]n or before 1934 the mosquito abaters made a ditch about two feet deep east of the shoulder of the First Avenue pavement." "Mosquito abaters" and their ilk continued to work, digging more ditches, paving roads, constructing a retention pond. Although the prairie itself was not touched, cumulatively the modifications wrought profound changes on the area's hydrological dynamics. The scientists' conclusion: "The invasion of the prairie by scattered trees and shrubs was without doubt largely due to a general lowering of the water table and weakening of the grasses."

In identifying hydrological tampering as the principal culprit, the authors picked the wrong guy from the line-up. Many years of research later, any expert will confirm that prairie flourishes in a wide range of soil moistures, but to survive it must burn regularly.

This dependence on fire is a challenge for conservationists. What do Americans think of fire? It burns down houses and scorches lawns. If consumed by flames, humans and our belongings don't sprout anew in spring. Much of what people construct on the landscape — roads, irrigation ditches, bluegrass lawns, and fire departments — intentionally or accidentally retards the progress of flame across field. Thus modern humans deprived the prairie of an element critical to its survival. Today, scientists realize, had the forest preserve managers simply set fire to the Riverside Prairie once every couple of years, they could have saved it.

But this prairie was not saved. Today it's a thick tangle of European buckthorn, an inverted distortion of the diversity there before, and a lesson that we as a species persist in not learning: even in a "hands-off" forest preserve our actions have consequences beyond what we can see.

Saving a Jewel

Santa Fe Drive runs through an industrial park at the confluence of I-55 and I-294 near Hodgkins in southwestern Cook County. Vehicles that can't be operated with a standard drivers license rumble up and down its length. Football-field-sized hangars with names like Petrovend Chemical, Sealed Air Corporation, and Wonder Bread line its sides.

But there are other sights along Santa Fe Drive. Between the gravel berm of the Burlington Northern/Santa Fe (BNSF) train tracks and the frontage road along the Des Plaines River lurks one of the last virgin wildernesses in Illinois, the Santa Fe Prairie.

The 1979 Illinois Natural Areas Inventory (INAI) identified this 10.8-acre site as grade A mesic and dry mesic gravel prairie. This means it's a pristine prairie growing on gravelly, moderately wet soil. The INAI originally identified three prairies of this type. One has since disappeared beneath the wheels of progress. Santa Fe is the largest of the remaining two in Illinois, perhaps in the world.

The Santa Fe Prairie survived initially by belonging to the Santa Fe Railroad. Railroad rights-of-way are typical places for prairies to survive. The first railroad companies generally acquired land in its pristine state.

A young Ph.D. candidate by the name of Robert Betz gave Santa Fe its second break. He was led there by the legendary plant taxonomist Floyd Swink, who had discovered the Santa Fe Prairie in 1946. Betz would later become "Mr. Prairie," and his visit in 1959 as part of a field trip initiated the prairie restoration movement much as the apple falling on Newton's head gave birth to the science of physics.

"I'd grown up in Bridgeport in Chicago, playing on vacant lots that we called prairies," says Betz, now a retired professor of biology, "but when I got to Santa Fe and saw what an actual prairie was, why, I guess you could say I got prairie fever." Betz continued his official career in molecular biology, but put most of his spirit in a parallel volunteer career. He developed an apostle's passion for locating and restoring prairie remnants throughout the Midwest. In the mid-1960s, when BNSF considered covering the prairie with fill from the newly constructed I-55, Betz intervened. His appeals eventually persuaded the railroad not to develop the land.

Fast forward 20 years to Stan Johnson, a semi-retired research chemist at Argonne National Laboratories by day, executive director and chairman of the Illinois & Michigan Canal National Heritage Corridor Civic Center Authority (CCA) in his spare time. Johnson had heard about the Santa Fe Prairie, understood that it fell within CCA's jurisdiction, but knew no one with first-hand knowledge of it. "In 1989," he says, "I went to a natural areas stewardship conference at Moraine Valley Community College expecting to find the people representing the prairie. I kept asking around, but there was no group associated with it."

Johnson volunteered his organization to coordinate advocacy efforts for the prairie, and some weeks later, accompanied by several stalwarts of the prairie restoration movement, he visited the site. "We were horrified to find that a giant oval track for off-road vehicle races had been carved in the middle of the prairie," Johnson recalls. Following a certain amount of negotiation, the railroad generously granted volunteers permission to begin managing the land. The volunteers blocked vehicle access, put up signs, and began the process of restoring the degraded areas. Johnson started writing inch-thick grants, wading through multilevel corporate and governmental bureaucracies, and traveling down numerous dead ends. After a decade of Johnson's hard work, a relatively intact Santa Fe Prairie finally concluded its passage from post-glacial landscape to 21st century wilderness haven when BNSF donated the land to the CCA. On June 16, 1998, a ceremony commemorated the site's official dedication as an Illinois Nature Preserve, a legal status that should guarantee its survival in perpetuity. Why does it deserve such a status? According to Karen Stasky, one of Santa Fe's volunteer stewards, because it's "the Midwest's equivalent to a patch of rain forest." Santa Fe harbors more than 250 plant species, including lilies, orchids, coneflowers, and wild grasses, most of which won't grow anywhere but high-quality prairie. Amid the loading docks and asphalt lots, the prairie persists much as it has for centuries, perhaps millennia.

Prophet of the Prairie

Dr. Robert Betz says every sentence as if it has a time limit. If the common name of the plant he's describing doesn't come to him, he'll use the scientific name instead. When he talks excitedly about something, which is pretty much all the time, he suggests a priest challenging the record for fastest Latin mass. It's the verbal quirk of a man always trying to do more than he can in the time allotted, and the biggest project he's been working on for the last 20 years is no exception. On 1,000 acres of cropland turned research facility at the Enrico Fermi National Laboratory in Batavia, Illinois, Betz seeks to create in one lifetime something nature took eons to assemble — a Midwestern tallgrass prairie.

For years, Betz had practiced a particular form of prairie restoration called remnant restoration. He searched the back roads and train tracks of Illinois, Indiana, and Missouri for pieces of the landscape that somehow escaped two centuries worth of plowing, so-called "prairie remnants." He often discovered them lurking in old settler cemeteries never planted with crops — tiny islands of native vegetation amid a patchwork sea of European and native cultivars like corn and wheat. Even if these unplowed cemeteries were overrun with weeds, the original vegetation hid out. One or two good burnings, a bit of strategic weeding, and the exotics faded out, the native species resurged. "The prairie was there, you see," Betz explains. "You just had to give it room to come back." He traveled the state convincing local cemetery boards to let him light fire to old cemeteries, sprouting one- and two-acre pieces of prairie in his wake.

But one- and two-acre patches scattered among the corn fields do not make an ecosystem. The larger the prairie parcel, the greater diversity of fauna it can support. At the moment, not one high-quality black-soil prairie remnant exists in Illinois large enough to support a single pair of prairie birds. Betz dreamed of a restoration that could one day sustain a small herd of bison. He persuaded Fermilab to lend its grounds to his vision.

Since the Fermilab grounds had been previously farmed, the techniques of remnant restoration would not work there. Betz and his volunteers would have to attempt a plowed-ground restoration. The difference between the two types of restoration is the difference between healing the sick and bringing the dead back to life.

How do you grow an ecosystem from scratch? First, volunteers gathered seed from every prairie remnant in the area. After sowing them in the fall, Betz and crew returned in the spring to find, as he says in mock horror, "a whole field of weeds." Specifically ragweed, amaranth, witch grass — the same exotic and native opportunists you'll find on every abandoned lot in Chicago. But hidden throughout, like grains of rice in a shag carpet, poked minute seedlings of the big bluestem, Indian grass, prairie dock, and other species the volunteers had actually planted. "I knew that these plants held a long-term ecological advantage," remembers Betz, "and would eventually push out the weeds." By the third year the balance had shifted, and that fall there was enough dried material to support a burn. "That's when things really took off," Betz recalls.

Based on his experience in degraded corners of the cemetery prairies, Betz predicted the prairie would return to Fermilab in three stages. The first stage consists of what he called "matrix species," those prairie plants with wider ecological tolerances, able to compete with nonnative weeds and shrubs on plowed and open ground. The 20-odd matrix plants include prairie dock, big bluestem, Indian grass, and wild quinine to name just a few. Once the matrix establishes itself, more conservative species like rattlesnake master and prairie dropseed begin to appear amid the original mix. The third stage prairie most closely resembles the presettlement landscape: an intricate jumble of 100 to 150 different species. Betz recites the names of the third stage plants — "the gentians, the lilies, prairie clovers, Mead's milkweed" — in a reverent litany, the way a child might describe the things she wants most for Christmas.

The poignancy is enhanced by the fact that Christmas still has not come to Fermilab. If one throws seed of a stage-three species like white prairie clover (Petalostemum candidum) into a degraded remnant prairie, within five to 10 years, Betz explains, "you get them blooming in flocks." But after nearly 25 years, not one stage-three plant has propagated on its own at Fermilab. The few that grew from the original sowing will stay alive and scatter their seed year after year, but they don't spread; they don't penetrate into the system. Betz's high-quality remnant restorations, like the Markham Prairie in southern Cook County, now bloom throughout the summer in successive waves of conservative stage-three flowers. At Fermilab, he concedes, "the best plots, the very first plots that we planted, are still only 40 percent of the way there." Betz proposes an explanation cautiously, affecting a scientific restraint at odds with his ebullient manner, "It would appear that it has to do with the mycorrhizae."

Mychorrizal fungi typify a category of microscopic organisms — bacteria, fungi, and their ilk — on which certain stage-two and three prairie plants seem to depend. In earth that was never plowed or grazed, these organisms still teem much as they have for millennia. In earth below cropland, pasture, or pavement, however, they're largely absent. These organisms appear to form symbiotic relationships with the more conservative prairie species — the lilies, gentians, and clovers from Betz's litany. These relationships seem to boost the plants' ability to carve out territory from the more ecologically tolerant matrix species, although no one can really say why or how. The soil below Fermilab is devoid of these crucial fungi and putting them back is much harder than making them go away.

Still, Bob Betz isn't panicking, so neither should you. In the world of prairie restoration, where success is measured by the quarter acre, the Fermilab prairie is nothing short of a miracle. In 1974, Betz sowed his first 10-acre plot with prairie seed. Today, more than 1,000 acres rest beneath a swaying carpet of native grasses and wildflowers. A dedicated group of Fermilab groundspeople and volunteers manage the land carefully, conducting prescribed burns and quashing invasion by exotic weeds. Betz points out that "the soil folks [scientists from Argonne National Laboratory] have finally gotten together with the prairie people," in a collaboration he's certain will reveal new ways to improve and accelerate the restoration process.

And the species count grows every year. Betz projects the confidence of a man who, eventually, solves every problem he faces. Sure, remaking an annihilated ecosystem is a task similar to what faced a certain king, when a fabled egg took a great fall. But one suspects that if Bob Betz had been there at that wall, Humpty would by now be together again.

Alex Blumberg works as a freelance print and radio journalist in Chicago. His work has appeared in the Chicago Reader, The Seattle Weekly, and on the national public radio program, This American Life.