Why Restore The Spring Flora Of Our Woodlands?

Compared to prairies and wetlands, there has been little work on species restoration for woodlands. Most woodland restoration is falling short.

That may be partly because good woodlands seemed to be relatively plentiful. Prairie restoration began on former cornfields. Starting from scratch was compelling. People like to demonstrate such Promethean power.

Only later did it emerge that much better prairie restorations could be accomplished by starting with large, degraded remnants. Less quickly dramatic, but more significant for the biota, such restorations have more potential to restore natural prairie composition and structure, in part because much original biota (invertebrate animals, fungi, bacteria, and more) may survive and repopulate. Dr. Ron Panzer found that many remnant-dependent insects were more likely to survive on “large Grade C” prairies than on tiny “Grade A and B” remnants, that at that time were the sole conservation focus. 

Trout lily. Pretty - but is too much of it a bad symptom?

Now we're more and more realizing that, though woodlands may look okay to average eyes, all our oak woods are degraded. They cry out for restoration, now, before they decay further. It would be foolish to focus woodland restoration on planting oak trees in corn fields. Decades to centuries would pass before there was sufficient canopy to restore most other species. And, to paraphrase Jerry Sullivan, comparing a restored natural remnant to a restoration-from-scratch is akin to comparing an amalgam of Beyoncé and Albert Einstein to a stitched-up oaf-creature staggering through the lab with wires hanging out of its neck. 

To put it less poetically, oak woodlands need conservation and restoration as much as prairies, and the best approach is to restore as many, as rich, and as big remnants as possible. 

A carpet of spring beauties and trout lilies.
 Is this the richness of nature? Or degradation?

Many woodlands seem precious because in spring they display an unbroken carpet of trout lily, spring beauty, and a few other survivors. Many people are coming to realize that such “richness” is an illusion, as most plant species of summer and fall have already been shaded out of such woods by excess canopy. Indeed, most spring flora is gone too. The ephemeral display that looks so timeless is a new phenomenon. It's all that remains of much more conservative, diverse (and mostly less ephemeral) species. The "ephemerals" survive by themselves because they get all the sun they need before the leaves close the canopy. What's missing today, in addition to the summer and fall-bloomers, is the larger diversity of less-familiar spring-blooming species that need sun all summer long.

Consider this list of the conservative wildflower species of a natural open oak woodland – all formerly common and widespread species: 

Scientific Name	C	Common Name
Actaea pachypoda	8	white baneberry
Allium burdickii	7	Chicago leek
Allium tricoccum	9	wild leek
Anemone quinquefolia	7	wood anemone
Anemonella thalictroides	7	rue anemone
Camassia scilloides	7	wild hyacinth
Caulophyllum thalictroides	8	blue cohosh
Dicentra cucullaria	7	Dutchmans breeches
Dodecatheon meadia	6	shooting star
Hepatica acutiloba	8	sharp-lobed hepatica
Hydrastis canadensis	10	goldenseal
Hypoxis hirsuta	8	yellow star grass
Lathyrus ochroleucus	10	pale vetchling
Lithospermum latifolium	10	American gromwell
Moehringia lateriflora	8	wood sandwort
Panax quinquefolius	10	ginseng
Pedicularis canadensis	9	wood betony
Taenidia integerrima	10	yellow pimpernel
Thalictrum dioicum	7	early meadow rue
Thaspium trifoliatum	8	meadow parsnip
Trillium grandiflorum	9	large-flowered trillium
Uvularia grandiflora	7	bellwort
Vicia caroliniana	10	wood vetch

If most of these species aren’t frequent in a woods, the reason is degradation. The woodland has been damaged (likely by fire suppression, excess shade, invasives, over-abundant deer, and over-harvest of ginseng, goldenseal, leeks, etc.). Such a woods is suffering. The solution is restoration. 

Here the trout lilies and spring beauties are mixed with large-flowered trillium, wild geranium, hepatica, early meadow rue, shining bedstraw, wood anemone, Penn sedge, woodland sunflower and many others. Vastly more biodiversity, natural quality, animal associates, and sustainability here.

The species on the list above have a quality ranking of 7 or higher in Wilhelm and Rericha (see Endnote 1) – except shooting star – which is on this list as a reminder that there are a great many other species missing from most woodlands today.  Not just the high conservatives, but many with rankings of 6, 5, and even 4 are missing or uncommon in most woods. Some woodland species (stargrass, shooting star, betony, etc.) survive today mostly in prairies, oddly. Such species would probably have a higher coefficient of conservativism if only our woodlands were considered. They remind us how much woodland biota has been lost, without our catching on until so late. 

The list doesn’t include sedges, partly because many people throw up their hands at such complexity, and I don’t want those people to give up at this point. (See Endnote 2.)

Most of the plants on the list above are not ephemerals. To many people these days the phrases “spring flora” and “spring ephemerals” are synonymous. But ephemerals are so called because they die back to their roots after spring is over. Of the 23 species above, only 6 do that. Most require sunlight for photosynthesis throughout the summer. 

Many people have wisely and helpfully cut the buckthorn out of woodlands in their care. Some have started controlled burns. Both are crucial. But few have taken the next steps. If the canopy is still too dense for bur and white oaks to reproduce, then it’s still too dense for most animals and plants of the oak woodlands. If most of the formerly-common flora is missing or rare, then most birds, butterflies, invertebrates, soil biota, etc. are gone or dying out as well.  

After April comes the May spring flora - a little taller.
Blooming here are wild hyacinth, wild geranium, and golden Alexanders.

One of my most educational moments came when Dr. Panzer did his second monitoring of the woodland/savanna complex at Somme Prairie Grove. After his first intensive sample, he told us that little savanna ecosystem survived, because that most characteristic savanna butterfly, the Edwards’ hairstreak, was not there. After a few years of restoration, Panzer was amazed to find the Edwards’ to be the commonest hairstreak on the site. A few apparently had survived on some edge – or, for all we know, around some neighbor’s insecticide-free garden. Most butterflies don’t travel very far. Nor do walking sticks nor even bumblebees.

The Federal-endangered rusty-patch bumblebee has been found at Somme. Some experts believe that the savanna or woodland is likely a key long-term habitat for it. Queens emerge early and need the spring flora. 

Let’s admit it. In the ecosystem, everything needs everything. To some extent. 

At least for some experimental sites, we need to give our oak woodlands the potential of full diversity restoration. 

This post was about “why restore the spring flora.” (See Endnote 3 for more illustrations.) A follow-up post describes how to restore the spring flora.

Endnotes

Endnote 1

Wilhelm, Gerould and Laura Rericha, Flora of the Chicago Region, Indiana Academy of Science. 2017

The “quality rankings” or “coefficients of conservation (C)” represent the degree to which a species is characteristic of an original or restored high-quality natural ecosystem.  

See also: Taft, J. B., Wilhelm, G. S., Ladd, D. M., & Masters, L. A. 1997. Floristic quality assessment for vegetation in Illinois, a method for assessing vegetation integrity. Westville: Illinois Native Plant Society and other regional databases as given in: the Floristic Quality Assessment website.

Keep in mind that these important, excellent coefficients are not based on pristine, healthy nature. They're based on what is. As Dr. Wilhelm has written, we'll learn much as nature recovers. That may be especially true of plant associations. An orchid expert once wrote that the prairie ladyslipper seemed to have an odd affinity for railroad tracks. There was nothing odd about it. We now know that railroad rights-of-way were in many areas the only places where high-quality prairie survived – because they weren't plowed or grazed. Similarly, many species survive in woodlands only along the edges of mowed trails – because those edges have that bit of extra light. We are likely to find that many species that seem restricted today to railroads, trail edges, and especially dry areas will return to the wetter mid-woods areas once there is enough light. Some survive today only in the dry because those areas lose their light more slowly. Some plants that survive today only on sandy soils (where the canopy also closes off more slowly) once were more widespread and may thrive more widely under healthy fire regimes.

Some prairies and sand savannas that have been long been burned and cared for are heart-stoppers. They take your breath away. No oak woodland today (in this region, at least) is even close to prime condition. A substantial woodland-savanna complex probably had five hundred plant species, or more. Most today have just one or two hundred. Well-meaning stewards sometimes refrain from species restoration for fear of “playing God.” It may be a wise, for comparison, to manage some sites without species restoration. But not most. Dr. Robert Betz, who studied prairies, emphasized that every tallgrass prairie in the world had been badly degraded over the decades, in ways we can only begin to understand. They need help to recover. In my own forty years of observing forest preserves, I have seen species after species drop out of site after site. They don’t come back, in most cases; there is no effective seed bank. And in any case, conditions today are different. Climate is changing. So are rain chemistry, animal populations, burn regimes, and so many other factors. At least on some sites, nature needs help in recovering the diversity that it once had ages to develop, without roads, cornfields, and subdivisions blocking the flow. 

Endnote 2

Sedges are important in woodlands. The list below includes some examples. I know them much less well than the forbs and grasses and would be happy to hear suggestions for what a better list would consist of.

Scientific Name	C	Common Name
Carex albursina	8	blunt-scaled wood sedge
Carex gracillima	7	purple-sheathed graceful sedge
Carex grayi	7	common bur sedge
Carex sprengelii	8	long-beaked sedge
Carex tenera	8	narrow-leaved oval sedge
Carex woodii	10	Wood’s stiff sedge

These lists are not “planting lists” for woodland restoration. They indicate species that, if missing, suggest that the ecosystem has been degraded. Thus, these lists are lists of indicators.

In other words, if I was making seed lists for restoration, I’d include these "7 plus" species plus all other missing species "6 and down" species that likely were there. Not just the high conservatives. More on that in the next post “How To Restore Natural Biodiversity To Oak Woodlands.”

Here's a conservative sedge, Carex sprengelii, hobnobbing with the conservative wild hyacinth. Our woodlands deserve all these beauties – and the whole of biodiversity. 

Endnote 3

A few more photos - with necessary captions.

This "gasping for survival" white oak woods looks great in May to some eyes. But there's been no white oak reproduction for a century. Less conservative red oaks at first started taking over, when the fires stopped. But now the tree reproduction is mostly pole maple trees. By June it will be obvious that little is left of the grasses, sedges, and wildflowers that so many animals depend on - and which comprise most of the plant biodiversity.

An early spring herb layer should look as diverse as this, and more. Blooming here are rue anemone, common blue violet, and wood anemone. Visible as foliage (and blooming soon) are wood betony, golden Alexanders, and woodland blue-eyed grass. Not so visible in this photo, but in this patch are yellow stargrass, Pennsylvania sedge, smooth tick-trefoil, meadow parsnip, cream gentian, shooting star, yellow violet, nodding wild onion, violet wood sorrel, and white lettuce. Nature wants to be diverse, if we give it a chance. 

In this woods the old white and bur oaks are dying. Some younger (more shade tolerant as seedlings) red oaks survive. Most reproduction is the densely shady basswood. Impressive numbers of quality natural shrubs survive including hazel, black haw, nannyberry, ninebark, and choke cherry. In spreading areas, buckthorn is dense, to the exclusion of most everything else. Conservative grasses, sedges, and wildflowers survive in pockets where they get more light, such as including pond edges, river bluffs, and trail edges. Such a woods is highly restorable, but less so every year. Many species, which we once gathered here for restoration elsewhere, seem to be no more. Without care, quality goes. 

A final photo - "wood pea" or "pale vetchling" - another reminder of what our woods could luxuriate in, once again. In 1927, H. S. Pepoon considered it "common on hillsides, in open woods." Today it's rarely seen, a threatened species in Illinois. It can revive impressively with restoration - though the deer may take a major toll. At Somme we put cages on some, to protect at least the early leaves (see lower left in photo). Deer seem to leave it alone later. With good restoration (and predation), there will be enough "rare" plants for all wildlife to eat and people to sometimes sit on for a picnic. 

Acknowledgements

Thanks to Kathy Garness and Matt Evans for proofing and edits.