Featured Favorite: Quercus Marilandica (Blackjack Oak)

Trees Forever Field Coordinator Debbie Fluegel is always looking for new opportunities to learn about the environment. The Illinois native has a passion for unique ecosystems, and this month she shares a hidden treasure of central Illinois: Henry Allan Gleason Nature Preserve, where the blackjack oak flourishes.

“Blackjack oaks thrive in poor soils and manage to survive where many trees perish,” Fluegel said. “It does well in poorly drained soils.”

Thousands of years ago, melting glaciers set the stage for today’s blackjack oaks. The glaciers left a sandy landscape southwest of Peoria, where the nature preserve now resides. The site is a great area to spot the trees, but this species is sprinkled across the southern parts of Iowa and Illinois.

The deciduous trees grow up to 50 feet. The blackjack oak’s bark is cracked into rectangular-like plates. The green leaves are shaped like eight-inch long dinosaur feet. Those leaves flare out, almost as if each cluster of leaves is like a shamrock growing on branches.

Every other year, the tree produces brown, striped acorns, and a slew of animals show up to harvest the nuts.


“Oaks, as a family, support the most numbers of ‘bird food’, caterpillars of butterflies and moths,” Fluegel says as she explains how wildlife feeds off the tree.

She’s spotted a number of turkeys eating the acorns, but it’s not uncommon for jays, woodpeckers, squirrels and deer to join in the feast.

These acorns are just one of the many examples of how trees are part of the foundation of our ecosystems. 


However, animals aren’t the only ones to benefit. Besides the obvious benefits every tree provides humanity like oxygen and beauty, humans can use the acorns for cooking and the bark for medicinal purposes.

According to PracticalPlants.org, the acorns can be dried and ground into a powder. This powder is sometimes used as a thickening agent in stews or an ingredient in bread.

The same website also cites using the tree bark “to ease childbirth, remove the afterbirth and ease cramps.”


How much you personally will appreciate the blackjack oak will depend on your comfort level, but no doubt, it’s a fascinating species.