A 266-year-old bur oak found near Nine Mile Creek

In 2024, University of Minnesota Professor Daniel Griffin, PhD issued findings from a study that he and his students conducted on bur oak trees near Nine Mile Creek.

According to their research, the oldest trees were around 15-20 inches diameter with stunted growth, due to partial shading by younger and faster growing trees. Of the 34 bur oak trees sampled along the bluffs above Nine Mile Creek, the team found 22 (65%) were more than 150 years old, seven (20%) were more than 200 years old and at least one tree was more than 266 years old.

“This old growth woodland is an important legacy of Minnesota’s natural heritage and is a critical remnant of long-term biodiversity in the state,” said Griffin. “This and future research could be useful for informing sustainability.”

So far, the oaks in the area have been resilient to changes in natural fire occurrences and urban encroachment but face new challenges, including climate extremes, diseases and blight and invasive nonnative insects.

What is a bur oak?

Bur oaks are massive oak trees native to central and eastern sections of the U.S. with a life span of up to 300 years. They have stout trunks and broad, rounded open crowns with stout and crooked branches. Their common name, mossycup oak, comes from the mossy scale or bur around its acorns.