It’s Oaktober!

An oak tree at The Morton Arboretum

This month we celebrate our national tree,

the magnificent oak (genus Quercus). More than 90 species of oaks are native to the United States and eight are native to the Chicago region specifically. Due to their longevity (they can live hundreds of years), oaks symbolize endurance, strength and wisdom. Prior to European settlement, oaks were the most abundant tree in northeast Illinois, accounting for more than 60% of the forest canopy. Today, oaks make up less than a third of the tree canopy of Lisle.

Oaks are a keystone species within an ecosystem, which means they serve as the foundation for other species to exist. Whether insects, birds and other wildlife, no other tree supports as much biodiversity as the oak. Some studies estimate that oaks support at least 500 different species, not including bacteria, mycorrhizae and other fungi. They also provide other vital ecosystem services, such as carbon sequestration, stormwater filtration, and the cooling of our suburban “heat islands” during warm months.

 As a “keystone” species, the removal and non-reintroduction of oaks has far-reaching consequences for the ecosystems in which we all live. Several studies list oaks as a “threatened” keystone species, both in the U.S. and globally. The Morton Arboretum and the Chicago Trees Initiative, among other local organizations, are working together to raise awareness about the need for oaks within our suburban and urban spaces.

 As individuals, we can learn more about the significance of oaks for our health and that of the planet. We can encourage our municipality to plant more oaks and to protect the ones that remain. We can become “tree keepers” for Openlands, a local conservation organization. We can also plant an oak tree in our own gardens, if we have the space and light. Future generations will thank us.

Resources:

Chicago Region Trees Initiative’s “Oak Ecosystems Recovery Plan”: http://chicagorti.org/sites/chicagorti/files/OERP-Full-Report-lowres.pdf

Lisle’s “Urban Forest” Summary: https://maps.fieldmuseum.org/CRTI/MuniCanopy/Lisle/Lisle.PDF

Morton Arboretum’s “Conservation Gap Analysis of Native U.S. Oaks”: https://mortonarb.org/app/uploads/2021/05/conservation-gap-analysis-of-native-US-oaks_sm.pdf.

Openlands “TreeKeepers” initiative: https://openlands.org/what-we-do/trees/treekeepers/.