The science behind Colorado's picture-perfect fall foliage this year
DENVER — Leaf peeping, the practice of driving into nature and photographing fall foliage, has become a customary event in Colorado. Places like Highway 285 over Kenosha Pass can turn into parking lots with eager drivers on the lookout for the subject of their next Instagram post.
But this fall, people in the Denver metro area hardly had to leave their front porch to experience the majesty of autumn in Colorado. And the season was especially beautiful in contrast to the truncated autumn of 2020.
Patrick Bohin is an arborist based in Boulder. He pointed out that in 2020, the fall colors were cut short by sudden temperature changes and early snowfall. On September 5, 2020, Denver hit 100 degrees. Three days later, the city recorded an inch of snow.
“It froze the leaves and the poor trees, they didn’t even have a chance to go into fall colors,” Bohin said about the dramatic temperature swing. “The leaves just turned brown and they froze.”
In 2021, however, the conditions could hardly have been better for pretty fall colors.
As the nights got colder and the days became shorter, the trees stopped producing chlorophyll, the pigment responsible for absorbing light that gives leaves their green color. With the green color gone, other pigments that produce yellow, orange and red leaves come to the surface, Bohin said.
“As the chlorophyll gets pulled away, those other colors show,” he added.
Bohin's passion for trees was apparent when he discussed the various fall colors, from the yellows of the cottonwoods to the carindal-colored leaves of the red oaks. But for Bohin, nothing compares to the sugar maple, which he called a “quintessential fall-color tree with the beautiful reds and orange colors.”
Temperatures are beginning to drop in the Denver area, with overnight lows near freezing. Soon, trees will be bare. Thankfully, we can always visit our camera rolls to relive the beauty of 2021’s autumn.
A gorgeous fall day out there today 🍂#cowx pic.twitter.com/ncX95i1M2l
— Rocky Mountain PBS (@rmpbs) October 22, 2021
If you have pictures of fall foliage you’d like to share, Rocky Mountain PBS would love to see them! Email your photos to coloradovoices@rmpbs.org.
Julio Sandoval is a multimedia journalist at Rocky Mountain PBS. You can reach him at juliosandoval@rmpbs.org.
Kyle Cooke is the digital media manager at Rocky Mountain PBS. You can reach him at kylecooke@rmpbs.org.
“Oh, my God, the colors are beautiful,” Bohin said. “The trees are so big; you can’t miss them.”
Bohin explained that even though the summer was dry in the Denver and Boulder area, particularly in the latter half of the season, the rainfall in the spring was tremendously beneficial for the trees. You may recall that the National Weather Service said that Denver had its wettest start to a spring since around World War II.
“We had a really good spring with good rain,” Bohin added. “The trees were able to take up water and be well hydrated and fairly healthy.”
And without an early snowfall, the fall colors stuck around longer than usual this year. “We’re not used to it,” Bohin said with a smile.