By Published: Dec. 15, 2014

Old Main Cottonwood in front of Old Main

‘Woodman, spare that tree!’ Oh, that’s what you’re doing? Cool!

When the young CU student saw two workers with ropes and helmets getting ready to climb the giant plains cottonwood tree outside of Old Main, terror struck her, and a feeling of impending doom grew in her stomach. Were they going to cut down this tree, the oldest and tallest on campus, which had given beauty and shade to the CU community on the Norlin Quadrangle for over 100 years?

She ran across the quad in a panic and confronted the workers. “What are you doing?” she demanded.

“We’re going to clone the tree,” replied Vince Aquino, an arborist with CU-Boulder’s Facilities Management. “We have to climb up into the canopy of the tree to take some cuttings.”

Aquino smiled as he saw the apprehension in the student’s face slowly fade. “Don’t worry,” he reassured her, “we’re not cutting the tree down.”

The student exhaled with relief, and her frown gave way to a smile. “I love CU-Boulder!” she exclaimed. She thanked the arborists and skipped off to class, grateful that this magnificent tree would continue to live in the quad, and also appreciative of the fact that her campus cared so much about the trees.

The Old Main Cottonwood is indeed getting new life. In October, cuttings were taken from the canopy of the tree by Facilities Management arborists Aquino and Joel Serafin. (See related video of the cloning above.)

The baby-cottonwood clones are developing roots.

The baby-cottonwood clones are developing roots.

The cuttings were then handed off to the care of Tom Lemieux, manager of the CU Ecology and Evolutionary Biology (EBIO) Greenhouse on 30th Street in Boulder. The cuttings have rooted and will remain in the greenhouse until sometime in 2015, when they will be planted outside. The cuttings will produce a clone: an exact genetic duplicate of the Old Main Cottonwood.

“Plains cottonwoods are actually relatively easy to clone because they naturally propagate by breaking into pieces and falling in the water and then re-rooting elsewhere,” says Aquino.

“It will be an identical genetic clone, without any genetic engineering,” explains Lemieux. “All we do is take cuttings and root them, which is the traditional method of vegetative propagation.”

“They should be ready next spring or early summer,” Lemieux predicts. “I think we’ll have enough cuttings for Vince to plant that genotype in several areas around campus.”

Joel Serafin and Vince Aquino, arborists

Joel Serafin and Vince Aquino, arborists

Plains cottonwoods (Populus deltoides subsp. monilifera) are known as the “pioneer trees of the plains” because of their hardiness and ability to withstand harsh weather conditions. Plains cottonwoods have an average lifespan of 70 years and reach about 60-80 feet in height.

The Old Main Cottonwood is between 135 and 140 years old, 108 feet tall and 19 feet in circumference at the base of the trunk. Thanks to its superior genetics and its proximity to the Anderson Ditch (which has allowed it to consume as much water as it needed), it is now the oldest and tallest tree on campus.

The Old Main Cottonwood, with its above-average age and height, makes it an ideal candidate for cloning.

Old Main, completed in 1876, was the first building on campus. Sepia-toned photographs show it standing tall and alone on a windswept mesa, surrounded by a bleak and arid landscape with nothing but rocks, rabbits and sagebrush. Joseph A. Sewall, CU’s first president, and his wife, Ann, lived in Old Main from 1877 until 1884.

Tom Lemieux, manager of the CU-Boulder greenhouse

Tom Lemieux, manager of the CU-Boulder greenhouse

President Sewall was the driving force behind the mission to improve the appearance of the CU campus through the planting of groves of trees. Timothy W. Stanton, who graduated from CU in 1883, recalled Sewall’s endeavors to beautify the campus with trees.

“His tall slender figure with a hoe or shovel guiding the water to the cottonwood trees, some of which he had himself planted around the university, was a familiar sight,” Stanton wrote in “Reminiscences of a University 65 Years Ago.”

The Old Main Cottonwood was planted in 1879 or 1880. An 1879 voucher from the CU archives showed the university spent $35 out of its general fund for 42 plains cottonwoods, which had a one-year warranty. Click here for PDF file of entire voucher.

1879 voucher for purchase of cottonwood trees.

1879 voucher for purchase of cottonwood trees.

In 1880, a second voucher showed the university purchased 43 more cottonwoods, at a price of only $17.50, suggesting that some of the first batch of cottonwoods planted might not have survived.

In 1888, faculty members and students started the tradition of planting trees on campus every Arbor Day, an annual tradition that continues to this day. In 2011, CU-Boulder officially became a “Tree Campus USA,” a designation awarded by the Arbor Day Foundation to recognize CU’s outstanding commitment to trees on campus.

The grove of cottonwoods that used to surround Old Main has dwindled over the years, as the trees have succumbed to age and died, but the Old Main Cottonwood continues to thrive on the south side of the building. However, at almost twice the average age of a plains cottonwood, its days may be numbered.

“It’s a huge, beautiful, majestic tree, and it’s got remarkable health for its age and species, but we have to keep a close eye on it because it’s quite old,” says Aquino.

With cottonwoods, there is the danger that falling branches might cause property damage or harm people on the ground. “It’s a species that grows very quickly, so it can have very soft wood that is prone to breakage,” Aquino explains.

Safety is the first priority for the arborists on campus. “We don’t cut corners with our risk assessment. When this tree becomes past an acceptable threshold of risk, it will have to be removed. That’s probably going to be within the next five to 10 years. Hopefully, it will be here longer than that, but we have to be realistic about it.”

With dedicated arborists Aquino and Serafin on duty, it’s hard to imagine the Old Main Cottonwood in better hands. “We keep a close eye on this tree. It gets climbed every year by a team of climbers who inspect literally every foot of it to check for defects and decay. We’re hopeful every year to get a clean bill of health, but we have to be realistic, and this tree, unfortunately, is near the end of its lifespan.”

“We do everything we can to keep it around as long as we can,” says Aquino. Now, thanks to the new baby-cottonwood clones taking root in the CU Greenhouse, even after the majestic beauty outside of Old Main eventually perishes, the genetics of this celebrated tree can live on in CU history for many future generations of students to admire and enjoy.


Special thanks to David Hays of the CU Archives for providing the pictures of Old Main below. Thanks also to Harvey Gardiner, former CU archivist, for an article on the cottonwoods in the Carillon (4/20/2001).

Old Main cottonwoods through the years

Laura Kriho is web and publications coordinator for the College of Arts and Sciences.