I am fortunate to have a stately white oak on my property that is probably about 170 years old. It was a sapling when my grandmother’s grandmother Lucinda was a child in Keokuk, Iowa, in the 1850s. My grandmother told me that her grandmother had fond memories of growing up in Southeast Iowa, and talked often about her life in this area. When she was growing up, Iowa forests and prairies were beginning to be turned into farmland.
At that time, Native Americans managed most of the land for their crops and for hunting with the judicious use of fire to keep forests more open. Lucinda often saw the Sac and Fox Indians canoe up and down the Des Moines River. In summer she enjoyed fishing and swimming in the river. In autumn there were nutting parties to gather hickory nuts, hazelnuts, and black walnuts, and she visited a pawpaw grove near the river bend.
When the river froze, skating parties were nightly events, with large log fires burning along the shore to warm cold toes and fingers. When frozen, the river was the best route for sleighs between neighboring towns. Stories like these now inspire me when I look at the white oak on my property. I want to keep my woodland as Lucinda remembered it when there was a greater diversity of wildlife in Iowa.
Of course, in many respects, there is no going back. The Carolina parakeet that was prevalent when Lucinda was a child is now extinct. The flocks of passenger pigeons were hunted to extinction. The wolf to the north and the prairie chicken to the west were extirpated. Nowadays, bison no longer roam in Iowa, except for a herd at Neal Smith Wildlife Refuge. Today, there are a lot more people in the world that need food. Consequently, almost all of the prairie has been turned into farmland.
And yet the white oak on my property is still here and its acorns still provide food for the many animals I share my land with, such as raccoons, squirrels, chipmunks, deer, and opossums, as well as bobwhite quail, wild turkeys, and bluejays. Since white oak acorns have fewer tannins than red oak acorns, they are more palatable to wildlife. White oak leaves are also the primary source of food for over 275 caterpillars, which are essential food for young birds in the nest.
Since oaks provide so much nourishment for so many species in our ecosystem, they are considered our most important of keystone species, crucial for sustaining our ecosystem.
Other keystone tree species for our eco-region include wild black cherry, black willow, river birch, shagbark hickory, and aspen. Shrubs, especially those that form thickets, are also important to provide cover and nesting sites. Some of the most biodynamic native shrubs include American plum, American hazelnut, chokecherry, and gray dogwood. Our most life-supporting woodland and prairie perennials include goldenrods, asters, and sunflowers. All of these plants provide the supporting structure of food for our native insects, bird, and mammals.
For me, as a horticulturalist, this information created a dilemma. I love all kinds of cultivated plants. What about Asian perennials such as peonies, daylilies, hybrid roses, and hostas? Don’t they support our local ecosystem? According to University of Delaware entomologist Doug Tallamy, who conducted over 40 years of research on the relationship between insects and plants, if at least 70 percent of an area remains in native vegetation, it is still enough to support most native insect, bird, and animal species.
This information provides a way to satisfy my love of plants while simultaneously providing a more compassionate way of living with the native birds and animals on my property. For myself, I keep a small cottage garden of cultivated plants within a 10-foot perimeter between the house and the surrounding picket fence. I line the picket fence with hardware cloth and spray deer repellent on everything within, otherwise deer and rabbits would eat most of it (except for the peonies). Outside the picket fence, there is a small lawn and mowed paths through woods and meadows, which help to keep chigger bites to a minimum. Beyond that, there are three acres where all the insects, birds, and animals I share my property with are free to browse and forage for food, except for a few oak saplings or wild plums that I safeguard with cages.
Winter is warmer now than when Lucinda lived here. When we have winter warm spells, I walk the property and weed out the plant invaders that spread aggressively such as Asian honeysuckle shrubs, multiflora rose, and autumn olive shrubs. These species can quickly take over the landscape and crowd out our native species, which can produce a death spiral for the ecosystem as the invaders deprive our native insects of a food source.
If you look at the leaves of honeysuckle shrubs in Jefferson County Park in November after the leaves of native species have fallen, there is very little evidence that caterpillars have chewed on the leaves. In addition, honeysuckle has allelopathic effects and emits herbicidal chemicals such as luteolin and apigenin from its roots, shoots, and leaves that kill the seedlings of our native species. The long-term effect of this toxin emitted in soil could eventually degrade our ecosystem to just a limited number of adaptive urban species, such as starlings, house sparrows, and the house mouse. Overall, the replacement of keystone species, plus the altered biochemistry in soil from introduced invasive species, contributes to the loss of habitat. For these reasons, Iowa has seen a decline in the populations of bobwhite quail, many warblers, meadowlarks, red-headed woodpeckers, nighthawks, and other grassland and open woodland birds .
I’m not suggesting we should go back to the 1850s, but the good news is that at least on my own property, I have turned around a degraded ecosystem more quickly than I originally thought possible. I’m happy to report that after only a few years, the work I have done has brought back several species indicative of a healthy woodland and woodland edge.
Five years ago, I did not see a single red-headed woodpecker, but in the last three years, they have become permanent residents. I also have field sparrows and the eastern meadowlark, which are important indicators of healthy grasslands and forest edges. And a long list of butterflies and native bees feed on wild geraniums, wild bergamot, woodland sunflowers, wood asters, elm-leaved goldenrod, and white snakeroot. Last year, bluebirds returned and nested. And this year, I heard the distinctive whistle of bobwhite quail; something I hadn’t heard for a very long time. I like to think that would make Lucinda very happy.
Further Reading
“A review on the invasion ecology of Amur honeysuckle; a case study of ecological impacts at multiple scales.” Rachel E.McNeish and Ryan W. McEwan, Department of Biology, University of Dayton, Dayton, OH 45460, Journal of the Torrey Botanical Society, 143(4) 367-385, 2016.
Bringing Nature Home, Douglas W. Tallamy, Timber Press, 2016
For more information, see JeffersonCounty Conservation.com.