Drought-stressed trees are experiencing a multitude of problems across the state

The hits just keep on coming. 

Following one of, if not the worst, snowpack years for the state, Colorado also just officially recorded its hottest summer on record, according to NOAA. This spells bad news for the annual brilliant displays of color dotting landscapes across the West and the trees producing them. 

“Aspens like things cool and moist. So when it’s hot and dry, they’re not having the time of their lives,” said John Murgel, a horticulture expert with Colorado State University’s extension program.

As the deciduous trees begin to enter dormancy, they naturally break down the green-colored chlorophyll back from their leaves into their branches, trunk and roots for later use, causing the leaves to turn bright shades of yellow, orange and red.

“If a tree is not stressed, then it can take its time and have an orderly descent into dormancy,” Murgel said.

When under environmental stress, though, this process can be rushed or abandoned altogether.

The result may be an earlier than normal, more muted and quicker display of colors than in a typical year.

Some reports indicate leaves are changing a full week earlier than normal, which is usually mid-September through early October. 

While Colorado doesn’t track how much of its nearly $30 billion tourism economy is from fall leaf peeping, a shorter window could have notable implications for mountain towns known for their fall colors. 

Murgel doesn’t envision a widespread hit to leaf peepers’ hopes, thanks in part to Colorado’s diverse topography and elevation.

“Even if the overall show of aspens in any one particular spot is shorter across the state, I don’t know that we should expect things to be noticeably shorter more broadly across the region,” he said. 

It’s still too early for Murgel and other experts to tell what the overall effect of the drought will have on aspens this year, and there is little certainty even after the seasons change. Without a control group to study, effectively diagnosing this drought’s impact on aspens’ colors would be difficult to pinpoint, Murgel noted. 

One thing for certain, though, is that peak fall foliage is coming and is coming quickly.

“It shouldn’t be long now that you’re able to go and head up,” Murgel said.