Rockton's Keefer Nature Reserve is home to NLI August Tree of the Month: a Chinkapin Oak

The William and Gayle Keefer Nature Reserve in Rockton, Ill., a 36-acre natural area owned by Natural Land Institute (NLI), is home to the August tree of the month: a Chinkapin Oak (Quercus muehlenbergii). The height of this Chinkapin is 82.5 feet, the average crown spread is 73.25 feet and the trunk circumference is 112 inches. Though the NLI doesn't claim this as a state record tree, it is about as tall as this oak variety gets. The April, May and June trees of the month are likely to be state records.

Chinkapin Oak is the least common native oak to Winnebago County and northwestern Illinois.  They occur only as isolated individuals or small groves in areas that are shallow to bedrock – mainly on bluffs along the Rock River, Kishwaukee Gorge and occasionally such habitat of its tributaries including Keith Creek at Aldeen and Alpine Parks as well as along Hall Creek (Howard D. Colman Dells Nature Preserve).

Alan Branhagen, NLI Executive Director, says, “Keefer Nature Reserve is a remnant bluff along the Rock River and just three mature trees adorn the crown of the hill – including our legacy tree which is the largest individual we know of in our region.”

Indigenous peoples valued the chinkapin oak for food: it's an acorn with the least amount of tannin so it's most easily cooked into a staple carbohydrate. Wildlife also values the mast of acorns produced from this tree, while the foliage is host to numerous insects that start the intricate web of life that surrounds us and ultimately helps us with all its free ecosystem services (cleansing air and water, pollination, food production, carbon sequestration, nutrient recycling and more).  

The tree is in the white oak group with a distinctive leaf that has blunt serrations down each edge of the leaf and without lobes like our other oak species. Local chinkapin oak trees are often gnarly, multi-trunked or of sculptural form rather than the straight growing trunks of most of our oaks. This helped spare them from the saw and each one a sort of living sculpture to admire, especially in the winter landscape when they are leafless. The leaves do turn a rich palate of orange to orange-red in the fall.

It's hard to know how old this tree is but it’s certainly been on this site for well over a century if not more. With its wide spreading crown, it’s a good indicator that this was open savanna at one time and prairie probably lapped against its west side. N.L.I.’s stewardship team plans to open this area up and restore its original habitat which will benefit the tree. The tree is in very good health and easily has another century or two of gracing this beautiful site.

“Chinkapin oaks make great street trees and landscape trees but for whatever reason are hard to find in nurseries,” said Branhagen. “They can grow quite fast once established, putting on two growth spurts in one growing season and are tolerant of all soils except those that are continually wet. They are exceedingly drought tolerant and climate resilient and we recommend you make the extra effort to find a chinkapin oak to plant – and help diversify our oak plantings which are so critical to the Nature around us. We plan on collecting acorns from this tree and offer them as legacy trees to our membership. Come see the tree in person at our Keefer Nature Reserve open house September 26th.”

Keefer Nature Reserve will officially open to the public on Thursday, Sept. 26, 2024 at a public opening event, 4:00 – 6:30 p.m. Attendees will be able to take guided tours and explore on their own, and see the legacy chinkapin oak. Light refreshments will be served. Rockton Township Historical Society and Burpee Museum of Natural History will be there to share historical and geological information about this preserve. Registration is requested for this free event at www.NaturalLand.org. Event parking and check in will be at Woodlands Park in Rockton (corner of Falcon Point Place and Park View Court).

Natural Land Institute launched the Legacy Tree Program in January 2024. It includes recognition of one tree a month that may be the largest of its kind, or have historical or cultural significance. Anyone may nominate a tree on private or public land from NLI’s 12 county region. Other components of the program, a list of the 12 counties, the online nomination form, and the tree of the month since January can be found at: https://www.naturalland.org/nlis-legacy-tree-program-january/, call 815-964-6666 or email info@naturalland.org.

About the Natural Land Institute:

The Natural Land Institute, an accredited land trust, is a 501(c)3, not-for-profit land conservation organization based in Rockford, Illinois and has protected 18,000 acres of natural land in Illinois since 1958. NLI’s mission is to create an enduring legacy of natural land in northern Illinois for people, plants and animals. For more information and to donate: www.NaturalLand.org or call 815-964-6666.