In drought-strapped Southwest Colorado, the outlook for fall colors this season is that they likely won’t be as vibrant or last as long as normal, but that doesn’t mean it won’t be worth getting out into nature before the leaves drop.
Southwest Colorado has been in a prolonged, multiyear drought. But this current dry spell began in October 2019 and lasted through the winter. Though high-elevation weather stations recorded about normal snowpack levels, researchers estimated snow levels throughout the region were below average.
This spring was all but void of precipitation. April saw just 10% of normal precipitation levels for the region, making it one of the driest months on record. From October to April, the region saw 70% of its average precipitation levels.
And then, the monsoon failed to show up in full force this summer. For the year, precipitation is about half of normal, according to a weather station at Durango-La Plata County Airport.
The U.S. Drought Monitor has the entire southwest corner of the state listed in an “extreme drought.”
All this to say trees are stressed, and that’s going to affect how bright leaves will be this fall and how long the fall color viewing season will last, said Dan West, an entomologist with the Colorado State Forest Service.
“They’re obviously stressed from lack of water,” he said. “And it looks as though the window for the peak ... is going to be a little bit earlier this year than we would see in a year of average precipitation.”
The driving force for leaves changing their color is day length, West said. But drought-stressed trees can shut down their systems earlier than normal to conserve energy and water.
“For the average person, if you go to the same cabin or location year after year, and know what day it typically peaks, you might see it happen earlier,” West said.
For the past two decades or so, the U.S. Forest Service has maintained and operated a Fall Colors Report for the most up-to-date information about how fall color conditions are shaping up in the forest.
Matt Tuten, a forester with the U.S. Forest Service’s Pagosa and Columbine ranger districts, said fall colors begin with golden yellow quaking aspen at the highest elevations and narrow leaf cottonwoods in low-lying cold areas as early as late August.
But aspens, which put on fall’s brightest show and account for 20% of Colorado’s forests, usually peak near the end of September to early October, which is typically a few weeks later than trees in most of the rest of the state.
“The color will usually last until a windy and wet cold front moves through, which could be as short as a few days or several weeks depending on the weather,” Tuten said.
After a few cold nights at lower elevations, Tuten said Gambel oak brush will turn orange and red. He noted that many low-lying oak woodlands had a hard frost this spring, which killed many new oak leaves.
“In these areas, oak colors will probably be subdued somewhat this year since these trees didn’t fully leaf out,” he said.
Michael Remke, a forest health research associate with Mountain Studies Institute, said as days shorten and temperatures drop, chlorophyll production, which provides trees with food, begins to slow before winter dormancy.
Trees stressed from drought, however, tend to accelerate this process, causing colors to not be as bright and trees to shed their leaves earlier than normal, Remke said.
And it appears, even if some late-season monsoonal rains were to arrive, it’s too late to change the fate of this fall foliage.
“Rain might help with some of the oak,” Remke said. “But at this point in the year, trees are investing more carbon into their roots, so it’s a little too late.”
But West said all things considered, it should be a good show.
“There’s a chance some of the stands will drop leaves earlier, and some of the colors will be muted/diluted because of drought stress,” he said. “But people will still have a decent show. That’s why it’s called Colorful Colorado.”
jromeo@durangoherald.com