salvaging knowledge from loss

Much of my childhood was spent amidst suburban sprawl. Through the 1960s, my once low density neighborhood almost completely filled in with residential and commercial development. Soon I lived in an inner suburb, and the sprawl had progressed many miles outward.

Later, I would rebel against this sprawl. But as a grade school student, all I could do was ride my bicycle greater and greater distances to explore the remaining open spaces.

Most of these open spaces were part of the Cook County Forest Preserve District system. Set aside much earlier than most other regional districts, they were for the most part exactly what the name implied: They preserved forests. In my greater neighborhood, they existed as bands along the Des Plaines River to the west, and the Chicago River to the east. Some were recreational places, mixed lawns, picnic groves, and softball fields surrounded by oaks. Others were simply dense bands of trees, with an occasional trail. What open places there were would eventually, without management, also become forest.

For a while, there were some fairly large privately owned open places, and I spent a great deal of time on a few of these. I watched as, one by one, they were destroyed.

One special place was located a few miles from my home. It was on the east bank of the Des Plaines River, and between Route 58 and Central Avenue. A narrow band of Forest Preserve with a horse trail marked the eastern part of this several hundred acres of open space, but most of it was in private hands.

We called it Carle Woods. In the late 1940s, Orlando Park had taken his Northwestern University ecology classes there on field trips, and there were various animals in the collections of the Field Museum and the Chicago Academy of Sciences with that name on the tags.

Many years later, I would sit over dinner with Richard Edgren in his Woodside, California home, and listen to stories of those field trips. He had been one of Park's students, and he told me of the detailed collections undertaken, the small plots marked off, everything for several inches down removed and sifted through to characterize that square meter of forest floor.

But in 1971 and 1972 I had only a name, and the knowledge that in one of those museum collections was a wood frog collected a long time ago, with a tag that read "Carle Woods."

Carle Woods was a very special place, and I would often wander it for many hours. I came to know the place very well. Near the river, the trees were tall, majestic,and it was easy to walk beneath them. There was only leaf litter and a few wildflowers and scattered shrubs, and never any standing water. To the east, the trees became smaller and the shrub cover denser and walking more difficult, and each spring the ground would flood to a depth well above my knees. It wasn't just a pond; the entire eastern edge of the woods was one unending swamp. But by mid-summer, it would be completely dry. Once, in this vast wetland, I heard the elusive wood frog call. But I never saw it there.

To the southeast, the site opened up. Here a rail line passed diagonally through the county-owned part of the site, and a set of power lines. It was wet here too, a continuation of the wooded wetland, but this area was kept open by periodic late summer mowing. Here, I found snakes in abundance, of several different species. I also found frogs, chorus frogs and leopard frogs, species typical of open and sunlit shallow wetlands. One day I came face to face with a gray fox, both of us startled and frozen in place. A moment later it vanished into the tall grass.

One day Carle Woods was sold, and soon the new campus of Oakton Community College was built there. Parts of the woods were left intact, in the sense that trees still stood there. But they were now small and fragmented, a pathetic shadow of what had been. The once vast wooded wetland was drained and reduced to a couple of vernal ponds, perhaps 100 feet across. The more open parts in county ownership remained much as they had been, with small trees encroaching into some once open areas, other parts little changed.

In the mid-1980s I received an inquiry about a specimen I'd collected at Carle Woods and later deposited in the collection of the Illinois Natural History Survey. By this time I had a better understanding of habitat, and I delved into available information to learn more about the site.

I started with the General Land Office Survey notes, which laid out township and section lines (in the 1850s, in this case). Using plat maps and witness tree data from these, I was able to partially reconstruct, at a coarse scale, what this place had been like just after the time of Euro-American settlement. Then, I visited a local historical society, and found a wealth of more recent records... maps of crop fields with records of annual yields and types of crops grown, plat maps showing ownership.

Not long before this, I'd met Robbin Moran a few miles to the north at Ryerson Conservation Area, which occupied a similar landscape position on the east bank of the Des Plaines River. Reading Robbin's paper on the presettlement vegetation of Lake County, and walking through the woods with him and asking questions, I came to understand more about what these places had once been, and why.

In the mid-1800s, most of the land west of the river had been treeless prairie for as far as the eye could see. Frequent fires, mostly set in the fall right after the first hard frost by Native Americans, had burned to the river but usually were unable to cross it. The river acted as a firebreak.

Trees lined the east, or downwind bank. First there was a very narrow band of floodplain forest, often only a few meters wide. East of this was a mesic forest, dominated by sugar maple and basswood. This higher terrace flooded infrequently, but did flood in 100-year events. Soils were loose, well-drained. Early spring wildflower displays would have been impressive, and as late as the early 1980s spectacular beds of trillium and mayapple covered the ground.

A little more to the east, where fine clays and silts washed down from the adjacent Park Ridge Moraine had accumulated, the soils became nearly impermeable. This sticky yellowish clay held ponded water each spring, then in mid-summer it would become very dry. Stunted oaks grew around the numerous ponds. Eventually, moving east and up the moraine slope, the trees opened into savannas or prairies.

It was a remnant of this ecosystem I'd once walked through at Carle Woods. The impressive trees near the river were sugar maples and basswoods. The denser community to the east was northern flatwoods, with swamp white oak, white oak, and an understory of sedges and shrubs. It was in these vast flatwoods ponds that I'd heard, but not seen, a wood frog at Carle Woods. At Ryerson, I did see them, did catch and photograph a few, before they faded away there as well in the late 1980s.

At Carle Woods, the treeline had once extended well to the east, another quarter mile or so. There was sugar maple and red oak in the western part of the woods, and to the east white oak and hickory. The modern treeline followed straight lines and 90-degree corners, so it wasn't surprising that almost half of it had been cut. The fields had been farmed until the 1930s and 1940s, when the Forest Preserve District had begun to buy them one by one and allowed them to go fallow. The snakes I found had occupied the newly fallow fields; originally those species would have been in other fields, natural grasslands and wetlands, a bit to the east.

I wrote those findings up, documented how the treeline had shifted over time, documented how those snakes I'd found correlated with those habitat types. It was one of the first scientific papers I ever wrote. Although it remained unpublished, it was later cited by others.

That experience awakened me to the temporal dynamism of plant communities. What we see today often bears little resemblance to what once was on the same bit of land. But the clues are there, for the careful observer.

There was one more lesson yet to come. A few years later, the college "restored" a section of prairie on former farmland along Rt. 58. It was very close to the river, very near where those 1850s surveyors had marked sugar maples and red oaks as witness trees.

There had been no prairie on the land now owned by the college, at least not anytime in the past 150 years, except for a tiny triangle where their entrance road crossed west of the river. It was easy enough to check; a shovel in the ground at the edge of that "restoration" produced light-colored forest soils. To adopt regulatory jargon, they hadn't restored prairie... they had created it (or at least a simplified mimic of it) where forest had once been.

Ever since writing that unpublished paper in about 1984, ever since documenting how the landscape of Carle Woods had changed, my first step on any potential restoration site has been to reach an understanding of what had been there before... and why it had been there. Successful restoration is more likely when one works with ecological processes, instead of fighting against them.