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Monday, April 21, 2025

"Bonfire Palooza" Raises Questions

 A good Instagram comment (by "mangigoroka") responded to recent photos of the Illinois Beach "Chainsaw Bonfire Palooza." 

Chicago region restorationists seem bound and determined to burn every last scrap of course woody debris. Is there scientific research to back this practice of making everything "clean"? Why burn course woody debris that a prescribed fire left behind- shouldn't repeated prescribed burns take down the coarse woody debris to"natural levels"? Don't you need those logs for 1) carbon sequestration 2) habitat for fungi and invertebrates 3) "nurse logs" and microclimate for certain plants? I wonder if there has been an overcorrection for fire suppression. Messy landscapes have more structural diversity. No? I appreciate the restoration work. I just question the strong emphasis in "cleaning" everything up in the Chicago region.

We appreciate these questions. We can’t speak for all “the Chicago Region restorationists.” It doesn’t seem impossible that there may be “over-correction” at some sites, but we haven’t seen it. We can speak for our work to reduce log piles at Illinois Beach.  



Large areas south of Dead River are badly and increasingly degraded by piles of pine logs. For some reason, these logs and branches are very slow to degrade. They don’t burn, perhaps because they’ve killed the grasses and forbs that would have provided the fuel to ignite them. Crown vetch is one of the few species that thrives under the pines, and from there it marches destructively out into the surrounding vegetation. 

Notice that the lower leaves of the black oaks in the background have been killed by a recent fire. That fire, like many before, had little impact on the log piles. 

We suppose these logs would ultimately rot or burn or be covered by blowing sand if we waited long enough. But they cover a substantial area, and every acre here is precious. A few animal and species are dropping out, possibly because their populations are too small to adapt to changing conditions. So we try to help.

South of Dead River we don’t pile or burn any logs beside the pines. Sadly, at the rate we’re going, it would be decades before we got them all burned up. But we see benefits in doing what we can and strategizing on how to do better.

As for the work last week, which drew the thoughtful comment that starts this post, that was a special case, which is now pretty much finished. Many trees along the main Dune Trail heading south from the parking lot had been cut to prevent them from falling on the trail. There were too many, and they were causing problems similar to the pines south of Dead River, killing the pricelessly high-quality savanna flora underneath. There were also, along the Dead River Trail, brush piles where trees had been cut up and piled because they indeed had fallen across the trails. Some people give arguments in favor of brush piles for animals to hide in. But this is a Nature Preserve where we don't want artificial structures. There are still vast numbers of naturally fallen trees, which serve that function. 

The wood cut and burned at this weekend’s palooza were all along those two popular hiking trails, generating questions from park visitors and hikers who passed, and prompting good discussions among visitors and stewards. Removing that ugly and unnatural mess not only benefits the ecosystem, it also makes this beautiful savanna more visible to those who visit it, some of whom therefore may be motivated to help care for it. 
At noon, we had lunch break ... and a bit of planning and discussion. Our log seats for lunch were later added to the fires. Notice smoke from two fires behind us along the trail. Notice also that there is still plenty of natural downed wood, as a natural part of the ecosystem. 

We are tickled to report that under some logs we picked up we found - brace yourself - native cockroaches. We love them, along with the rest of the fairly unique flora and fauna that thrive here. We help all as best we can and are so happy to have these opportunities. 

Three more photos of the evil log piles and the struggling flora near them: 




Here Sharon Rosenzweig points to the killer crown vetch that proliferates under some of the piles. She will spray herbicide on it. 

            Quality flora survives near the piles, but it's thinner and weaker than farther away. 

Downy yellow painted cup is one of many endangered or rare species that would appreciate a bit more living space restored. 

For other Illinois Beach posts, click here and here

Acknowledgements

Thanks to Zoey Raines for good edits. 

Tuesday, April 1, 2025

Morton Grove Prairie Nature Preserve Rises Again!

Morton Grove Prairie seemed mostly gone. Years of minimal stewardship had left most of the site without prairie plants or animals. Instead the occasional visitors mostly walked through head-high brush and stands of tall goldenrod. 

This sad story was told in a post in October 2023.

Whose fault was it? Not the Morton Grove Park District that owned it. This good agency had no ecosystem scientists on staff, unsurprisingly, and they responded to what minimal input they got. Keeping rare Nature Preserves healthy in most cases is too hard without multiple inputs - including public participation and support. 

Now - an amazing comeback was recently reported by the stewards team, empowered by Friends of Illinois Nature Preserves. It is reproduced below:

It Takes a Village to Save a Prairie

Admiring a Year of Good Stewardship ... Inspiring the Year Ahead 

March 18th 2024 - a new chapter begins for Morton Grove Prairie. 
A new community of neighbors assembled by Friends and the North Branch Restoration Project starts to battle the brush.


On April 3rd, 2024 the neighbors were joined by the Peregrines - a travelling Friends group of stewards mostly in their twenties and thirties. Gray dogwood, brambles, and willow bit the dust. Eileen Sutter, in the foreground, began recording the many prairie species that survived, many in small numbers.

Some of the early leaders - Eriko, Larry, Maria, Stone and Rebeccah - squint towards the camera. They claimed they were blinded by the prairie's bright future.

In May, the Morton Grove Park District removed many cottonwood trees that had grown and gradually shaded the eastern edge of the prairie. Without this important "heavy lifting" - restoration of much of the site would not be possible. 

Bit by bit the new stewards team identified needs and divided up responsibilities.

Ken heroically brushcut tall goldenrod, sumac resprouts, and other aggressive species throughout the growing season. And he taught others to do the same!

By summer, some of the better parts of the site were looking good.

But most of the prairie was just gone. It would not come back without help.

Weekday evening workdays focus on collecting seeds in the better areas. The work delivered many picturesque golden hours and dreamy sunsets. Here, Maria searches for seed seed of early-blooming species.


Here that selfsame Maria stands with seed bounty collected in the prairie by the new group in 2024 - in total, about 7 gallons of roughly 35 species. A generous supplement of hyper-diverse seeds also was donated to the cause by the nearby North Branch Restoration Project. Some of the genes in those species came from Morton Grove Prairie in the first place.

January 12th, 2025 - Those seeds were planted in every needy place.

March 27th, 2025 - the prairie burned! 
Trained and certified staff and volunteers with the Friends managed the fire. 
Bit by bit health is returning. 


Congratulations to All.

Here's to another Great Year Ahead!

Endnote: Prairie Species Rediscovered Here in 2024.

Achillea millefolium (common yarrow)

Agrimonia gryposepala (tall agrimony)

Allium canadense (wild garlic)

Amorpha canescens (leadplant)

Andropogon gerardii (big bluestem)

Anemone canadensis (Ccanada anemone)

Anemone cylindrica (thimbleweed)

Antennaria neglecta (field pussytoes)

Antennaria sp. (plantaginifolia or parlinii)

Apocynum cannabinum (hemp dogbane)

Asclepias purpurascens (purple milkweed)

Asclepias syriaca (common milkweed)

Asclepias tuberosa (butterfly milkweed)

Asclepias verticillata (whorled milkweed)

Caenothus americanus (new jersey tea)

Calamagrostis canadensis (blue joint grass)

Carex stricta (tussock sedge)

Carex bicknellii (bicknell's sedge)

Carex buxbaumii (buxbaum's sedge)

Cirsium discolor (field thistle)

Comandra umbellata (bastard toadflax)

Coreopsis tripteris (tall coreopsis)

Cuscuta sp. (dodder sp.)

Dalea purpurea (purple prairie clover)

Danthonia spicata (poverty oat grass)

Desmodium canadense (showy tick trefoil)

Dichanthelium scribneranium (scribner's panicgrass)

Dodecatheon meadia (eastern shooting star)

Elymus canadensis (canada wild rye)

Erechtites hieraciilfolius (american burnweed)

Erigeron philadelphicus (philadelphia fleabane)

Eryngium yuccifolium (rattlesnake master)

Eupatorium altissimum (tall boneset)

Euphorbia corollata (flowering spurge)

Euthamia graminifolia (grass-leaved goldenrod)

Fragaria virginiana (wild strawberry)

Galium obtusum (blunt-leaf bedstraw)

Gentianella quinquefolia (stiff gentian)

Geum laciniatum (rough avens)

Heuchera richardsonii (prairie alumroot)

Helianthus grosseserratus (sawtooth sunflower)

Hesperostipa spartea (porcupine grass)

Hypoxis hirsuta (yellow star grass)

Juncus tenuis (path rush)

Lactuca canadensis (canada wild lettuce)

Lespedeza capitata (round-headed bush clover)

Liatris spicata (dense blazing star)

Lobelia spicata (pale-spiked lobelia)

Maianthemum stellatum (false solomon's seal)

Monarda fistulosa (wild bergamot)

Oenothera gaura (biennial gaura)

Oenothera pilosella (prairie sundrops)

Oligoneuron rigidum (stiff goldenrod)

Oxalis stricta (tall woodsorrel)

Oxypolis rigidior (stiff cowbane)

Packera paupercula (balsam ragwort)

Panicum vergatum (switch grass)

Parthenium integrifolium (wild quinine)

Pedicularis canadensis (wood betony)

Penstemon digitalis (foxglove beardtongue)

Persicaria amphibia (water smartweed)

Phlox pilosa (downy phlox)

Polygonatum biflorum (smooth Solomon's seal)

Pycnanthemum virginianum (Virginia mountain mint)

Ratibida pinnata (gray-headed coneflower)

Roegneria subsecunda (bearded wheat grass)

Rudbeckia hirta (black-eyed Susan)

Rosa carolina (carolina rose)

Rosa blanda (smooth wild rose)

Schizachyrium scoparium (little bluestem)

Scutellaria parvula var. leonardii (prairie skullcap)

Silphium integrifolium (rosinweed)

Silphium laciniatum (compass plant)

Silphium perfoliatum (cup plant)

Silphium terebinthenaceum (prairie dock)

Sisyrinchium albidum (white blue-eyed grass)

Solidago altissima (tall goldenrod)

Solidago juncea (early goldenrod)

Solidago nemoralis (gray goldenrod)

Sorghastrum nutans (indian grass)

Spartina pectinata (prairie cordgrass)

Sporobolus heterolepis (prairie dropseed)

Stachys sp. (hedge nettle sp.)

Symphyotrichum ericoides (heath aster)

Symphyotrichum laeve (smooth blue aster)

Symphyotrichum novae-angliae (New England aster)

Symphyotrichum oolentangiense (sky blue aster)

Symphyotrichum pilosum (old field aster)

Teucrium canadense (american germander)

Thalictrum dasycarpum.(purple meadow rue)

Tradescantia ohiensis (Ohio spiderwort)

Trillium recurvatum (prairie trillium)

Triosteum perfoliatum (late horse gentian)

Verbena urticifolia (white vervain)

Veronicastrum virginicum (culver's root)

Viola sororia (common blue violet)

Zizia aurea (golden Alexanders)


Credits

The language and photos of this post were assembled by the Morton Grove Prairie Nature Preserve stewards community. 


Wednesday, March 12, 2025

Hard-hitting Headfire - a video captures it

As this 51-second video unfolds, Dave, Eriko, and Jo have happy smiles on their faces. They've spent more than two and a half hours putting in the backfire and the sidefires for this 158-acre burn. Once they're secure and the headfire shown in the video is lit, the human work is done, and the powerful - seemingly unstoppable (but see Endnote 1) - force of fire takes over.

Here, on March 10, 2025, Dave ignites the headier with a rake (see Endnote 2). The fire trailing behind him for its first half a minute is barely noticeable. But watch what happens next.  

Dave is pulling a rake of burning grass. The fire behind him is minimal, at first. But bits of burning grass fall off, starting little fires - and the rake picks up more grass as it goes - which then starts to burn and fall off in pieces - starting little fires every foot or two as he walks. He mostly just hikes the north edge of the trail, but he veers off a bit to avoid some areas where the grass along the trail is thin.

Next, our eyes are drawn to the increasingly intense fire that runs with the wind from the little flames Dave ignites. It's this raging fire that does the work the preserve needs. 

But, for contrast, watch the video again, and focus on the little fires which continue burning back toward the trail, flames just a few inches tall - a good contrast between a backfire and a headfire. 

Illinois Beach hosts one of the finest, largest, and most important remnant natural areas in the state. More than sixty endangered species populations depend on these savanna, prairie, and wetland habitats - as do thousands of other species of rare animals, plants, fungi, bacteria, and more. Parts of these habitats have been under-burned and suffering, ecologically, because of lack of resources. (See Endnote 3.)

The evidence of degradation due to that lack of resources is widespread. Growing patches of such aliens as buckthorn, crown vetch,  and Japanese silverberry are only a part of the problem. Overabundant native woody species are the bigger part; they grow so dense that they shade out the grassland matrix on which this savanna depends. These out-of-balance species include grape, ash, aspen, and even oak. 

Thus those black oaks with persistent dead leaves exploding into fire represent some of the most important work that this burn is accomplishing. The oaks, like the grasses, are key to this ecosystem, but they need fire to keep them in balance. Many of these oaks will be "top-killed" by this fire, but they'll all re-sprout. Savanna oaks often live for long periods of time as "grubs" - or repeatedly re-sprouting oak bushes. The bigger oaks and some of the smaller ones will continue to grow larger. 

The crew that gets the credit for this fire consisted of one excellent burn boss from the Illinois Department of Natural Resources supervising a dozen folks in two teams (of mostly volunteers) from Friends of Illinois Nature Preserves. The 360 degrees of fire breaks added up to 2.4 miles, all carefully walked and tended by the two crews (one for the east half of the perimeter and one for the west). (See Endnote 4.) There will be another, longer post on the compelling details on this and another burn that we did on the same day - "coming soon" on this blog. 

Endnotes

Endnote 1.

This fire looks ferocious. Is it now unstoppable? Given the mix of loose sands, dense brush, and wetlands, it's probably not stoppable with vehicles. But there's a way to stop it. The answer is to fight fire with fire, that is, build a controlled backfire down wind. If we wanted to stop it, we'd go to a deer path or trail or road or whatever was handy and set a line of those little backfires that looked so mild on the video. We'd use rakes, water, and flappers to keep those fires from going downwind.  That fire would back slowly toward the coming headfire and use up the fuel. If needed, for speed, we might light a serious of close, parallel strip fires - from firebreak to firebreak - and when the headfire reached the line of no fuel, it would just go out. 

Endnote 2.

Igniting with a rake seems old-fashioned to some. Most crews use a drip torch. But some of us find rakes to have advantages in some situations. They're lighter to carry on a long day. They never run out of fuel or get plugged up. The lessen the amount of petrochemicals being deposited in the ecosystem. And when you're not igniting, that same rake is useful to reduce fuel around benches, signs, and certain young trees or shrubs, which we may want to spare from the burn for various reasons. 

Endnote 3.

The Friends of Illinois Nature Preserves assembled in 2019 because our Nature Preserves System, long a global model, was deteriorating from lack of sufficient staff, contract funding, and volunteers. The Friends work through education, advocacy, and training and empowering volunteers - especially expert volunteer leaders.

This burn was a good example. Illinois Department of Natural Resources (IDNR) heritage biologist Melissa Grycan, the logical person to lead today's burn, was required to be in central Illinois to burn another needy preserve on that prime day. There are more than 600 Nature Preserves, most of which need controlled burns, and only a handful of active burn bosses among the State staff. 

March 10th had the best burn weather in months, and Melissa trusted the Friends crew sufficiently that she did the work of rounding up Division of Forestry burn boss Dave Griffith, to be staff leader on the team today. He and the whole team deserve credit and thanks. Two certified Friends burn bosses were in the crew today, and more staff and volunteer burn bosses are in training - today for example. Many of the volunteers working and getting experience today may well become much needed burn leaders. And it will be a great growing season for the cherished ecosystem at Illinois Beach. 

Endnote 4.

An aerial photo showing the extent of the burn.

The principal (easy) firebreaks were the park road to the north, a wide trail to the northeast, Lake Michigan to the southeast, a park trail on the south, Dead River to the southwest, and the Dead River Trail and Nature Center parking lot and entrance road on the northwest. 


Acknowledgements

Thanks to Rebeccah Hartz, Jo Sabbath, Kathy Garness and Amy Doll for proofing and edits. 



Wednesday, February 19, 2025

Moving Ecosystems

What determined in whether a spot was prairie or woodland? 

Another way to ask, annoyingly to some (see Endnote 1): What determined "the most advanced stages of succession” for our prairies and forests for any given place. 

  

Southern Wisconsin, northern Illinois, and much of adjacent states, when first entering recorded EuroAmerican history, consisted of patches of prairie and timber (a word often used then for savanna and woodland). In some areas it was said that every 80-acre farm had some prairie and some timber. 

 

Henry Allan Gleason and other smart observers puzzled over the seemingly random nature of these patches in some areas. Gleason noticed prairie sites where the evidence suggested they once were woods - and visa versa. While it’s true (and reassuring to the orderly mind) that prairie occurred predominantly wherever the land was level (or on southwest-facing slopes) and that timber was predominant wherever the land was hilly (especially on north-facing slopes), striking exceptions were common.   


Fire tends to burn hotter and spread faster uphill than downhill. North slopes tend to be wetter and more likely wooded. Southwest slopes are the driest as they’re baked by the afternoon sun. Rivers may stop fires, so the east sides of rivers tended to be wooded. Wetlands sometimes stop fires; then again, with increased fuel loads, when they do burn they can burn very hot. Oaks (especially bur oak) tend to resist fire damage. But maple, the “climax” tree of long-unburned areas, tends to be wiped out when chance brings a hot fire through it. 

 

And what other principles might apply? Might knowledge of them help conservation decisions be rescued from the “playing God” charge - by appealing to history? 


One day it came to me, having watched brush patches and prairie patches move in response to controlled burns, that in this region the “climaxes” moved. Indeed there was order, but it was a different kind of order. 

 

I had noticed as I managed little nature preserve areas that patches of trees and shrubs sometimes shaded out and killed off nearby prairie areas. But also, with fires predominantly from the west, vigorous prairie fires sometimes killed trees and shrubs to the east of the grassland.

 

What could have prevented this sort of thing from operating on the larger scale … especially where so many patches made such a complex mosaic? Also, what could have prevented one community type from just taking over?

 

My hypothesis came to be that the “climax” vegetation in some areas was the northeast edge of both prairie and timber patches. There was a “rock, paper, scissors” dynamic going on here. On average, given the prevailing westerly winds, a prairie would tend to burn into and replace timber on the east edge of the prairie (the west edge of the woods). Also, because here in the temperate zone the sun at midday shines not from straight above but from the south, patches of timber would tend to shade out and replace prairie on the north edges. 


Oak Groves Move Northeast - Passing Two Hills

In this graphic, up is north, and the nested circles represent topo lines of hills.
Green represents oak woodland. White is open prairie. (See Endnote 2.)

Some hilly, north-facing slopes were prairie. And some flat, rich areas were timber. Most any piece of land in complex mosaic areas might alternate between prairie or timber. But perhaps the patches would move (at varying speeds, depending on topographics) generally northeast, irregularly, like giant amoebas. The southwest-facing slopes would last longest as prairie, but (except in extreme situations) they’d eventually be shaded by woody plants and become savanna or woodland for a while. Northeast-facing slopes (except in ravines and other extremes) would last longest in the woodland phase.


It's tempting to think that savannas might have been more stable, as their rich turfs had components of most all prairie and woodland species. But it would also be tempting to think that during periods of mild burning a savanna might evolve into woodland, and during periods of severe burns, pure prairie might win out. 

 

Such processes may have made for the grassland and woodland biodiversity that we find today and which is vanishing so rapidly and completely in many areas from lack of good stewardship … and understanding. 

 

Endnotes

 

1. Many wise people over the years have argued strenuously that “succession” is a word that is not useful today; it has been made scientifically confusing and misleading by misuse. The problem with “succession” (a fact that happens in nature, as keenly noticed by Henry Chandler Cowles) is that the concept was ossified wrongly by Frederick Clements. People began to believe that what happens without fire or other “disturbance” is true nature. It's “good” and leads to nature's most noble state, according to which most land in the Midwest would be maple forest. 


Even as late as Curtis (The Vegetation of Wisconsin 1959), the perspective was that oak woodlands would naturally become maple. But our understanding of “nature” now includes “biodiversity.” Curtis himself described how a diverse mesic oak woodland (with hundreds of species of plants and thousands of species of animals) loses most of its species when shady maples take over. Most conservationists today would see that as an ecologically tragic loss of a rare remnant of nature – resulting from neglect or mismanagement. 

 

On the other hand, if we’re not to use the word succession, we need other words to describe what happens in situations when, after some form of degradation followed by good stewardship, conservative species gradually displace most “weedy” species. Some people refer to prairies and savannas as examples of "fire climax."   


A related question: how much attention should we pay to such “climax” states when making conservation decisions? Some people look back on the past for our model. And whether or not we seek to restore past states, knowing a site's former ecological state can certainly inform conservation decisions. 

 

2. The graphic above is considerably less than half-baked and way simplified. How this dynamic would work in various areas would also depend on soils and many other features. Also, the panel representing "Future, Sometime" would only hold if we had fires as ferocious as past fires sometimes were. 


3. It may be a minor question what the “original vegetation” of a site was. For millions of years, our grassland and woodland communities evolved under the influence of lightning-caused fires. Following the retreat of the most recent glacier, lightning fire is widely believed to have been largely replaced by human-set fires. But the species, relationships, and communities were largely those same millions-of-years-old ones. 

 

Consider this thought experiment: A patch of prairie, in the absence of fire for a century or two, is invaded by the plants and animals of adjacent savanna and oak woodland. Many of the conservative prairie plants and animals die out, and many conservative savanna animals and plants become established in a mosaic of rich savanna and oak woodland communities. Then the adjacent former prairie and original savanna/woodland get destroyed. But the "patch of former prairie" becomes a nature preserve. Would it be best to cut down the trees to return this preserve to its original prairie state - if it loses its savanna/woodland biodiversity in the process and gains back no prairie biodiversity, because it no longer exists nearby? To me the answer in clearly no; save the inter-relationships among the oaks and the other savanna species; this is especially true as savanna biodiversity is even rarer than prairie biodiversity.  

 

4. Timber patches vs Prairie patches. It would be interesting to use existing topographies and ask a computer to model how vegetation patterns might have changed over time. The graphic above shows a "prairie grove" moving through surrounding grasslands. But an isolated patch of prairie might move through timber somewhat similarly. In an area that had equal amounts of both, the amoeba-like movements would be endlessly blending into each other or swallowing each other. The principles followed would include: 

  • Prairie patches on flat ground would tend to expand into timber to the north and east, where fire would be hottest. They'd need to shrink on their south edges because of shade and from their west edges because fire would have no momentum there. 
  • Timber patches on flat ground would head (and last longest) to the north because of shade and, to some degree, to the east because fire in frequently burned woods is moderated by lack of fuel. And a grassland on the east edge of timber might get shaded out by young trees because fire would have little opportunity to build momentum and heat while burning through the woods.
  • Prairie would spread fastest and last longest on south and southwest-facing slopes, in proportion to how steep the slopes were.
  • Timber would spread fastest and last longest on north and east-facing slopes. 
  • Timber would also spread fastest and last longest when protected by bodies of water to the west and to a lesser extent to the south, because fires would tend to have to back into those places (giving the prevailing west or southwest winds during fire season); a backfire is much less destructive of timber than a head fire. 

5. How fast did these patches travel? Once again, the answer would depend on soils, slope, aspect (the direction the slope faces), nearby water bodies, etc. But two additional elements are fun to think about. Bur oak is the principal tree in this dynamic because they are so much more resistant to fire than any other. The other tree species grow behind the protection of the bur oaks.


Bur acorns are big and heavy (It's hard to get established in a dense turf of grasses.) and thus not dispersed by birds or wind. They're planted by squirrels. Gray squirrels tend not to go more than 50 yards (?) from trees to cache their acorns. (Might fox squirrels have been different?) It takes many years for those oaks to grow big enough to make new habitat that the squirrels feel confident to venture out from.  


Bur oaks live for 300 or 400 years - said to be this region's longest-lived tree. It might be hard for fire to dislodge mature oaks from an area. If so, would that suggest that an area colonized by bur oaks would comfortably remain as timber for three or four hundred years? Other tree species can in time grow where bur oak reduces prairie fire intensity, but bur oak cannot reproduce in the shade of most other tree species. Perhaps intense fire has a better chance to eat away at the edge of a grove once the other species have replaced the bur oaks. 


6. The map below by Marlin Bowles and Jenny McBride shows the 1880s vegetation of six townships along the north edge of Cook County. Yellow is prairie. Green is timber. Blue is wet. 

Deer Grove is the large woods to the northwest. Busse Woods is the large woods in the south middle township, northeast of a wetland.

Timber is on the east side of the DesPlaines river, which spans this map from north to south on the east.

The Somme preserves are in the upper right (northwest) corner. Somme Prairie is west of the West Fork of the North Branch of the Chicago River. Notice that the prairie crosses the river there. The savanna and woodland are on the poorer soils of the moraine.


And what about the many smaller, isolated prairie groves? Isn't it fun to imagine what was going on with them?!

7. The maps of McHenry and Lake Counties, Illinois, shown below were suggested by Don Osmond. 

The striking difference between McHenry (left) and Lake (right) probably reflects differences in what the map-makers wanted to bother with more than differences on the ground. That is, the Lake County map seems more detailed.


Don also supplied a letter from 1835 in which a settler (C. Fletcher) described the prairie southeast of Wauconda with these words: “Traveling on them you are out of sight of land, as it is called here, that is timber. Then a grove of timber that runs along by some stream a mile or two wide, and then prairie as far as you can see except small groves of one to five acres.”

Map Key

beige = prairie

pale green = savanna

dark green = woodland or forest

blue = water


On the above map in Lake County (right), there are a dozen small prairie openings in the oak savanna and about that many isolated denser groves surrounded by prairie or savanna. But these maps were extrapolated from the original Public Land Survey which mostly mapped features that crossed survey lines, so there may have been many more smaller prairies or groves. McHenry County (left) looks very different, but that may just mean a less detailed mapping. 


For the letter by C. Fletcher, see here.


8. John Curtis, author of the Vegetation of Wisconsin (1959), is one of the people who has wondered about these questions. In a somewhat different context, on page 304 he wrote: 

Thus it appears probable that the mesic prairies moved eastward by a series of jumps, each following a catastrophic destruction of the pre-existing forest. If that forest had developed sufficiently close to a climax condition so that it would have eliminated the oaks, then a true prairie resulted, whereas if the forest contained any proportion of oak (other than red oak), then a brush prairie was likely. 


9. When this "moving ecosystem edges" concept first filled my mind for a while, decades ago, I was thrilled with it. I imagined there might be here – if not a “Great Discovery” – at least something useful. Then I forgot about it. There are so many competing challenges in conservation, and life can get busy. But Will Overbeck recently remembered a conversation about all this and asked if I had a graphic for his Wild Things talk. So I resurrected it. Thanks, Will. Perhaps some people will find it interesting.