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This OAKtober, Celebrate Oak Trees’ Critical Role in Local Ecosystems

Swamp white oak leaves and acorns at Harms Woods-South.

From tiny acorns on the trails to full tree crowns in the forest canopy, oak trees support hundreds of plants and animals in the Chicagoland area. Because of their environmental impact—maintaining a rich mix of plants, insects, birds and other animals wherever they grow—they’re considered a keystone species. They also play a significant role throughout the Forest Preserves of Cook County by improving soil quality, purifying the air and regulating the temperature. OAKtober: Oak Awareness Month, proclaimed by the governor of Illinois in 2015, helps by recognizing the importance of oaks in the community as more than one-third of all oak species are now facing extinction.

There are approximately twenty species of oak trees that are native to Illinois. You may be familiar with white oaks (Quercus alba), the state tree of Illinois but can you also identify a swamp white oak (Quercus bicolor)? Swamp white oaks are a widespread tree species in wet, wooded areas in the Chicago region. They also make excellent street trees and you may see one planted alongside the busy streets in Chicago’s Loop.

It is common to encounter swamp white oaks and many other related species across our 70,000 acres. If you want to test your ID skills, the best way to learn is to look at the actual trees! During your visits to the Forest Preserves, use the Field Museum’s Common Oaks of the Chicago Region guide to help you identify features on real oak trees. And if you’re planning a trip to the North Branch Trail System, check out our North Branch oak maps. (Hint: you should be able to find a plethora of swamp white oaks in the North Branch picnic groves and preserves.) Feel free to give them a big hug after you learn their names. No judgment!

Be on the lookout for tree maps of other Forest Preserves regions in the future. We’ll be sharing more tree information as we continue to gather data for our picnic grove tree inventory.


OAKtober Events

This month, we’re hosting events to celebrate OAKtober! The Chicago Region Trees Initiative also offers OAKtober activities through its partners.