Chance Discovery Reveals Illinois' Largest Basswood Tree

Scientists find towering specimen in Jersey County nature preserve

Apr. 6, 2026 at 9:55am

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Researchers from the National Great Rivers Research and Education Center were surveying trees in the Palisades Nature Preserve near Grafton, Illinois, when they stumbled upon an unusually large American basswood tree. After verifying its measurements, the team submitted the tree to the Illinois Big Tree Register, which has now recognized it as the largest recorded basswood in the state.

Why it matters

American basswood trees are not commonly found in Illinois, making this discovery of a true champion specimen an exciting find for the state's natural heritage. The tree's location within a protected nature preserve also highlights the importance of conservation efforts in preserving rare and significant flora.

The details

While conducting routine tree surveys in the Palisades Nature Preserve, researchers from the National Great Rivers Research and Education Center noticed an exceptionally large American basswood tree. After taking initial measurements, they contacted the Illinois Big Tree Register to begin the verification process. The tree's circumference, height, and crown spread exceeded that of any other recorded basswood in the state, earning it the title of Illinois' largest.

  • The tree was discovered by researchers in the summer of 2025.
  • The National Great Rivers Research and Education Center submitted the tree's measurements to the Illinois Big Tree Register later that year.
  • The Illinois Big Tree Register has now officially recognized the Palisades Nature Preserve specimen as the largest recorded American basswood in the state.

The players

Chris Sedivy

Research specialist at the National Great Rivers Research and Education Center.

Dan Runge

Seasonal field technician at the National Great Rivers Research and Education Center.

Lyle Guyon

Senior scientist at the National Great Rivers Research and Education Center, which manages the Palisades Nature Preserve.

Illinois Big Tree Register

A program run by the University of Illinois Extension that tracks and recognizes the largest trees of each species in the state.

National Great Rivers Research and Education Center

A research and education organization that manages the Palisades Nature Preserve in Jersey County, Illinois.

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What they’re saying

“(Seasonal field technician) Dan Runge said, 'That's a big tree,' Basswood trees don't usually get that big.”

— Chris Sedivy, Research specialist

“We contacted the Illinois Big Tree Register and started the process of submitting the tree as a candidate for listing. We went through the verification process and found out we had a state champion.”

— Lyle Guyon, Senior scientist

What’s next

The National Great Rivers Research and Education Center plans to continue monitoring the champion basswood tree and exploring the Palisades Nature Preserve for other potential state record-holders.

The takeaway

The discovery of Illinois' largest recorded basswood tree highlights the importance of conservation efforts and scientific exploration in protecting the state's natural heritage. This rare find underscores the value of maintaining diverse ecosystems and the potential for unexpected ecological treasures to be uncovered, even in well-studied regions.