Early May 2024

The morning was deliciously foggy. As I walked by this grassy pond, a Virginia rail and a sedge wren flew up, freshly back from the south. Welcome back. Our stewardship is as much for the animals as the plants. 

We don't see the rails often. We do hear their calls. We are glad to feel their neighborly presence. 

At the edge of the oaks, the rare wood betony (red-purple) bloomed side by side with the commoner prairie betony (yellow). The red form seems to like the woods more than the prairie. 

Burn scars shock some people. Looking raw and wounded, they're from tree-clearing last winter and are a valuable part of the woodland ecosystem. Diversity requires such scars ...

... for some biota. Those are the species that evolved for a specialized niche - created when the fallen trunk of an ancient tree finally passes through the final stage of its life cycle. For many trees in savanna and woodland ecosystems, that stage is not rot. It's fire. As these scars succeed they host impressive waves of algae, mosses, and vascular plants. The endangered Bicknell's geranium is one of many species that we find only or mostly where wood burns out the competition for a while. 

Fire is obviously violent. But there are more subtle kinds of violence:

Our many big cottonwood trees are shady invaders, not typical of a healthy savanna. Their seedlings can't compete in a competitive turf. Their shade kills some species that would otherwise thrive. Is not death by shade a kind of violence? 

Worse in the photo above, the dense shrubs and trees in the background represent a more final brutality. As they wipe out all natural plants and animals beneath, how ruthless should we be in return? We cut, burn, sow, and pamper. 

In Somme Prairie Grove's bur oak woodland areas ...

... we have, over the decades, eliminated or thinned buckthorn, ash, hickory, box elder, and more. At least 90% of the woody stems belonged to invaders. Red oaks (shorter-lived than bur or white) help by falling down dead; other trees grow bigger. The thin-barked hop hornbeam in the foreground was girdled to kill it. Hornbeams make deep shade. To the top left above, you can see other trees so dense they look like a picket fence. They should go. We'll get to them.

With shade reduction at the right pace, a thrillingly complex turf of rare plants develops. More and more conservative species move around and increase, year after year. 

Oak woodland is now recognized as one of our rarest and most threatened ecosystem types. In Paul Nelson's drawings below - not as sunny as a savanna; not as shady as a forest - oak woodland is in the third panel down: 

Looking at the same visual from above:

                Prairie                              Savanna                         Woodland                         Forest

The "herb layer" of the woodland may be as rich or richer than a prairie:

Plants shown above: In bloom, wood betony, white trillium, and rue anemone. 

In the open savanna, scarlet painted cups are visible. This species is almost gone from the region. Somme has an over-population of white-tailed deer. The blooming one above is in a deer-exclusion cage. Below it, to the right, is one in a vole exclusion cage. How will we divide what time we allot to caging which species this year? 

 

Last year was a painted-cup bonanza, a bit of which is shown below:

In this patch we counted 358 plants. Overall we counted 572 plants in 19 separate populations. Since we first seeded this species from a nearby population in 2016, every year it has been a thrill to see the first ones emerge, and then more and more, in some years. But we continue to puzzle over its fickle unpredictability. 

Scarlet Painted-cup Numbers at Somme Prairie Grove

	2016	2017	2018	2019	2020	2021	2022	2023	2024	2025
# of plants	45	1	73	29	162	85	101	572

A native shrub thicket (hard to manage) in a wet area where most fires, like this year's, burn up to the edge, and then stop. When we pass this thicket during the year's Breeding Bird Census, we regularly see orchard orioles, willow flycatchers, hummingbirds, indigo buntings, and more. They like it.

Seen from another angle, this thicket shows top-killed gray dogwood to the left and monstrous cottonwoods behind, towering over the mature bur oaks, behind them. Those cottonwoods should go. In their area they "take up all the oxygen in the room." Nature can't recover under their shade and level of water consumption. 

Counterintuitively, a main problem for oak savannas and woodlands is too many trees. Decades without fire left the bur oaks (below) too close together. 

We girdled some to kill them. Tall, skinny trees fighting for the light do not lead to healthy oak woodland. 

Here a half-dozen stems of bastard toadflax have invaded the top of a mound of dropseed grass. The toadflax, wood betony, and scarlet painted-cup are hemiparasites. We now know that many parasitic animals, plants, fungi, and bacteria play crucial and ultimately healthful roles. 

In this Illinois Nature Preserve, visitors are required to stay on the path system unless authorized to step off for stewardship or scientific study. Somme Prairie Grove includes 2.7 miles of maintained trails. These footpaths are minimal ...

... but they're designed to resist erosion and are reinforced, where they pass through wetlands, with the wood of cut invasives. 

In the photo below, a path winds through open savanna.    

Here the oaks are mostly small. Farmers had cut most long ago. Bur oak was the principal tree species here. The dark young tree to the right (above) is a bur oak we had protected from deer and fire. One to a few trees per acre are enough for a savanna. How much time will we invest in protecting more? 

In the map below, most trees are invaders. The original bur oaks survived farming in three small areas. Bur oaks return, but they're slow.  

The pussy willow patch below got protected. For decades it was a minor presence, stems never more than a foot tall, as it was occasionally burned by fire and the re-sprouting stems then eaten by deer. 

Willows are a valuable component of the wet savanna community. So a few years ago we found time to put a cage around this one, and we watched it grow to a size that seemed secure. But buck deer responded by raking their antlers on its trunks last fall until the bark was gone ...

... killing most stems. Scores of new shoots are now emerging, which the deer will probably eat. Cage it again? 

At the end of March, we notice woodhen nests.  

As it happens, a few times each spring, snowfall nearly buries the hen. We see her head in the whiteness. She is devoted.

On April 28th, she's still there. Incubation takes 20-21 days. I peek in again on May 2nd ...

... and only egg shells remain. For 14 days, until they can fly, she'll do her best to keep the chicks safe and protected. We emulate her dedication and persistence. 

Acknowledgements

For a longer and more technical version of this post, click here.

Cook County Forest Preserve staff deserve credit for technical supervision and prescribed burns. We volunteer stewards do most of the rest. Illinois Nature Preserves System staff, Commissioners, and protective laws are important back-up protection, as are Friends of Illinois Nature Preserves. 

Thanks to Paul Nelson (and the Tallgrass Restoration Handbook) for the drawings showing the structure of prairie, savanna, woodland ,and forest. 

Base preserve map by Carol Freeman. Graphic edits by Linda Masters.

The splendid Virginia Rail photo is from Tinyfishy on Flickr.

Thanks for proofing and edits to Eriko Kojima.