Trees on the CU campus. Courtesy photo

The Ancient Trees of Boulder County


This is the oldest resident in Boulder County. She took roots in Boulder in 1878 or ‘79, making her about 140 years old.

She’s so old that moved here just a few years after Colorado became recognized as a state. So old that cows roamed the campus when she arrived, and CU had recently hired its first ever female professor, Mary Rippon. The school itself was only three years old and taught 44 students.

This ancient resident of Boulder is a plains cottonwood tree, and she lives on the south side of Old Main on the University of Colorado campus. She’s believed to be one of the oldest trees in Boulder, according to the CU website.

The old cottonwood on the CU campus. Photo from CU’s website

This tree was planted along with 42 other seedlings, but she’s the lone survivor, made even more miraculous by the fact that a typical cottonwood only lives to be about 80. She towers taller than 100 feet.

While Boulder is packed with trees — the city’s urban forestry division alone manages about 51,000 public trees — the CU campus is one of the best places in the city for tree-lovers.

It wasn’t always that way. In fact, the campus started as a treeless stretch of earth. Today, it is home to about 5,000 trees, spanning more than 100 different species, including 50-plus-year-old littleleaf lindens, honey locust trees and 14 of Colorado’s 24 native trees.

Because of this, CU has been named a Tree Campus USA by the Arbor Day Foundation for eight years in a row.

To be named a Tree Campus, a school must have a specific tree care plan, have a tree advisory committee, dedicate money to its tree program and more.

You can stroll through campus and learn about the trees in a Tree Walk Self-Guided Tour. Also, make sure you download the Tree Walk Map.

If you want to dive in deeper, CU’s Museum of Natural History offers several guided tree walks every year, usually in May and October. The walks are free and open to the public. You’ll learn about the different trees and their significance to Boulder. For tour dates and times, check

A map of the trees of Thompson Park. Courtesy photo

Thompson Park in Longmont

The nearby Boulder County city of Longmont has about 1,461 acres of trees, but the best place to experience a group of them is at Thompson Park.

This beautiful park has more than 182 trees over five acres, and the diversity is impressive. You will find 74 different types of trees here.

Thompson Park is one of the city’s first original parks. Back in the late 1800s, it was used for grazing cows. The first trees planted here were kept alive with buckets of water carried from the St. Vrain River. These trees still thrive today.

Take a self-guided tour of Thompson Park and learn more about its ancient residents with The Trees of Thompson Park document.

One Response

  1. I loved your article. Cottonwoods are so important to the environment. My research shows cottonwoods can live up to 150 years old, do you think it might be the difference between the four species?

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts

december, 2023

Sponsored Business

Boulder, CO
7:04 am4:36 pm MST
Feels like: 30°F
Wind: 0mph WSW
Humidity: 59%
Pressure: 29.73"Hg
UV index: 0
3 am4 am5 am6 am7 am
43°F / 34°F
55°F / 34°F
61°F / 37°F
63°F / 39°F
59°F / 34°F