Fall colors hard to predict, but Vail Valley’s color season may be a good one | VailDaily.com

Fall colors hard to predict, but Vail Valley’s color season may be a good one

EAGLE COUNTY — Despite a summer of drought and fire, the season's fall colors appear to be on schedule — maybe.

In this part of the state, peak leaf season hits between roughly the last week in September and the first week in October. Thanks mainly to cooling temperatures and declining sunlight, northern areas can put on their fall displays a little earlier, while the south's colors may peak a bit later.

Colorado State Forest Service Entomology Program Specialist Dan West said it's hard to tell with any precision just how one leaf season may change from another. There's a lot at play, from geography to elevation to weather to whether a hillside gets more or less daylight.

A prolonged heat wave can affect fall foliage. So can a wet spring, an early frost or early snow storm. Any of those things can bring enough of a shock to trees to cause leaves to simply turn brown and fall off.

Usually, though, trees ease gradually into the changing seasons. As temperatures cool and daylight hours shorten, trees stop making chlorophyll. Leaves then trade their summer green for underlying colors of red, yellow and orange. That's where fall colors come from.

Trees usually depend on "abundant" moisture in the growing season, West said. While moisture has been generally near seasonal norms in the northern part of the state and the Front Range, much of the state's Western Slope has been at some level of drought for more than a year. The state's southwest corner has been particularly hard hit.

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Trees under stress

The Dolores River, which flows near Durango, was recently running at 9 percent of its normal flows.

West said the crippling drought in that part of the state could lead to fall colors emerging somewhat earlier than normal. Without enough water, trees can stop making chlorophyll earlier than normal, leading to a premature color show.

Again, though, forecasts are imprecise at best, West said.

At the Colorado State University Cooperative Extension office in Mesa County, horticulture specialist Susan Carter said she's seen some stress-induced color starting to appear in the leaves of cottonwood trees in lower elevations. Trees on the Grand Mesa, which tops out at just more than 10,000 feet elevation, are also starting to show some color here and there, she said.

Part of this is believed to be due to drought.

"From a tree's point of view, we've been dry since late last summer," Carter said.

Could smoke contribute?

Assistant State Climatologist Becky Bolinger's office doesn't deal much with botany. But, she said, she's heard theories that smoky skies can also affect trees' seasonal behavior. Trees respond to both daylight and temperature, and smoke in the sky can affect the amount of light plants receive.

"In drought, there are certain types of vegetation that are in stress," Bolinger said. "They may go into dormancy to protect themselves."

West said some of that may happen in southern Colorado. Again, though, only the trees know, and they aren't telling.

Overall, though, clearing skies and continued dry conditions can lead to good fall colors.

Given that the current forecast for the state calls for mostly dry conditions, blue skies, cool nights and little rain are a good recipe for fall foliage, West said.

"I think we're set up for a perfect season," West said.

On the other hand, West said people interested in fall color tours need to build a little flexibility into their plans.

"If I go on the same drive at the same time every year," the colors may not be there this year, West said.

Vail Daily Business Editor Scott Miller can be reached at smiller@vaildaily.com and 970-748-2930.

Where to leaf-peep

Here’s a look at a handful of fall color drives in and around Eagle County

• Up north: Take Colorado Highway 131 north of Wolcott to Colorado Highway 134. Drive east to U.S. Highway 40 and then south to Kremmling. From there, take Colorado Highway 9 into Summit County.

• The drive south of Eagle to Sylvan Lake State Park can be a stunner.

• From Gypsum, take the Cottonwood Pass road into Garfield County.

• From the top of Vail Pass, take Shrine Pass down into Red Cliff.