Oak Savanna Conservation

If you could go back in time 200 years, you would find the landscape of McHenry County to be a patchwork of prairies, wetlands and oak-hickory savannas (open woodlands). Most of the prairies were converted to farmfields 150 years ago, and many of the wetlands were drained for farming in the early part of the 20th Century. But many oak groves survived the area’s settlement as part of farms. The open woodlands offered a good place for livestock to graze, plus in an earlier time, the family woodlot provided fuel for heating and cooking.

There are oak and hickory trees in McHenry County that were here before European settlers moved into the area in the 1830s. Imagine the stories these sentinels could tell!

Sadly, however, many of these old friends are reaching the end of their lifespans. The trees’ age plus the stress of living in a developing area could mean that the oak groves – like those you see at Emricson Park – may not survive the next 20 years.

An oak savanna is much more than just a grove of trees. A whole community of plants, animals, birds and insects are found in oak savannas and not other woodlands.

Historically, fires pushed through the woodlands every few years, keeping all but the most flame-tolerant species in check. This kept the woods open, and a certain set of plants and animals adapted to this environment – and to each other.

Several bat species, many birds like Cooper’s hawk and American bluebird and a large number of butterflies like the Karner blue have a strong preference for the open “structure” of an oak savanna. The over-grown thickets that we find today do not accommodate a diversity of plants and animals – they tend to be dominated by just a few species that drive the others out.

There are simple things we can do to ensure the local heritage of oak savannas survives for future generations. These include:

Give oak trees the opportunity to regenerate.
In other words, the oaks need to have the right conditions to produce seedlings, and those seedlings need to have the opportunity to mature into trees. Today, it is common in yards and public areas to see mowed grass under oak groves, creating a “park-like” appearance. From the oaks’ perspective, this means the seedlings that sprout will never have the chance to become trees, because they will be mowed down to maintain the lawn. If homeowners, businesses and local governments convert part of the lawns to a naturalized landscape with native grasses and flowers, young trees will have a chance to grow in these “lawnmower free” zones.

Another problem that keeps oaks from regenerating is the growth of invasive shrubs like buckthorn and honeysuckle. The invaders crowd out the oak seedlings, and while they do not directly kill the older oaks, they effectively ensure that they will not be able to reproduce. Clearing the brush out from under oaks will help sustain the oak groves by allowing seedlings the chance to grow and one day take the place of their aging parents.

Preserve oak groves as part of development projects.
Today, federal and local regulations protect wetlands and streams, but there are very few communities with regulations that protect trees. Woodstock has tree preservation standards for the City’s site plan review process, but there are no rules to keep a landowner from cutting down all the trees on his property tomorrow.

Conservationist John Muir once said: “Going to the woods is going home, for I suppose we came from the woods originally.” Let’s make sure our great-grandchildren are able to go home to the oak woods where our great-grandmothers made their homes once upon a time.

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Resource information:

Each spring, the McHenry County Soil & Water Conservation District in Woodstock holds a tree sale. They sell a variety of native oak trees (white, bur, chinkapin) and native shrubs to go along with the oaks. You can contact them at 815-338-0099 x3, or visit their website at www.mchenryswcd.org to obtain an order form. Orders can be placed up until March 24 th.