From a small plane above Colorado’s mountains, Dan West has been getting a bird’s-eye view of the state’s trees. He conducts forest surveys and has been watching for the first patches of autumnal yellow and orange to emerge.
But this year, the early fall colors come with a caveat: For many trees, it’s not the seasons shifting that’s making them change. It’s drought.
“Really this year we’re seeing a lot more effects from the drought than we are just from that autumnal kind of seasonal change that we would typically see,” said West, the state’s Forest Service lead entomologist.
Trees across the state are showing signs of drought stress, and that’s causing some to change color and drop their leaves earlier than they normally would. And, West said, the fall foliage is running about a week ahead of its typical schedule in many places.
“It’s just hard to be a tree in Colorado,” he said. “And it’s really hard for us to think about recreating and all the things that we all love to do in our forests when trees are struggling so mightily. But also, we all need water and we all live in Colorado for a reason – many of us for the recreation values and just the ability to get to the mountains and be able to drive up and just see some of our nature and a lot of that is being threatened.”
That could make for an earlier leaf-peeping season – but it may not necessarily mean a better one.
Under normal conditions, trees take their cue to begin changing color from the shortening days of late summer and early fall. As daylight decreases, trees begin forming a separation layer between their leaves and branches. Chlorophyll, the pigment that makes leaves green, breaks down and reveals the yellow and orange pigments that were already there.
Cool nights and sunny days help produce the vivid colors people associate with Colorado leaf peeping season.
But drought adds another stressor. As of early September, nearly 89% of Colorado’s land area was classified as being in drought, according to the U.S. Drought Monitor. Parts of central and western Colorado are experiencing extreme or exceptional drought.
When trees don’t have enough water, keeping leaves alive can become costly. Trees lose water through their leaves during photosynthesis, so a drought-stressed tree can essentially decide it can’t afford to keep them around.
“Trees are dropping those leaves early because they’re like, ‘Well, if I keep going through photosynthesis, then I’m losing more water,’ and as they’re losing more water, of course they’re suffering,” West said. “And so they’re like, ‘Well, I’ll just shut this down early and drop these leaves early.’ And that’s typically what I’m seeing through a lot of the central part of Colorado.”
That means some of the yellowing and browning visible around Colorado right now isn’t necessarily the beginning of a spectacular fall display. It can be a sign that trees are shutting down early to conserve water. And West said he’s seeing trees grow smaller leaves and fewer leaves overall, which could ultimately mean a less impressive fall display in some places.
Because of that, he said this leaf-peeping season will be a “mixed bag” across the entire state.
He said Colorado has seen a pattern in recent years of drought and above-average temperatures alternating with more typical conditions – a pattern he sees as increasingly familiar. That could change the way people think about Colorado’s traditional leaf-peeping calendar.
While the timing of peak color has never been fixed, historically predictable trips to a favorite mountain cabin or trail may become harder to plan as temperature and precipitation patterns fluctuate.
“We’re moving now into our new normal,” West said.
For leaf-peepers, that may mean the best strategy this fall is to go a little earlier, watch the weather and choose locations where trees have had better access to moisture.
The outlook isn’t uniformly bleak.
West said northern Colorado has fared better in part because of monsoonal moisture, and he expects some of the best leaf-peeping opportunities this season to be in the northern mountains. For those planning a trip, he said colors are running about a week earlier than they would in a more typical year. That means the window for peak color is shifting earlier, too.
Early- to mid-September – northern Colorado mountains
Steamboat Springs, Buffalo Pass, Rabbits Ear Pass and the Colorado 14 corridor: Early color is beginning at higher elevations as early as this week. West said the weekend of Sept. 19-20 may be particularly fruitful for early leaf peeper hopefuls. He said northern Colorado is among the best bets this year, thanks in part to better monsoonal moisture.
Mid-September – central Colorado
Kenosha Pass, Guanella Pass, Peak to Peak Scenic Byway and Rocky Mountain National Park: Fall color typically progresses from higher elevations downward through September.
Late-September to early-October – Gunnison/Crested Butte area
Kebler Pass and surrounding West Elk Mountains: One of Colorado’s largest aspen stands, with the pass generally becoming a major fall-color destination in September and early October.
Late-September through early-October – Western Slope, San Juan Mountains and southern Colorado
Grand Mesa and the Grand Mesa Scenic and Historic Byway: Look for golden aspens and other fall foliage around Grand Mesa and the communities of Cedaredge and Paonia. Silverton, Ouray, Telluride and the San Juan Skyway. The 236-mile loop through Southwest Colorado is one of the state’s classic fall-color routes.
La Veta Pass and the Sangre de Cristo Mountains: Higher-elevation foliage typically arrives before lower-elevation areas, with La Veta Pass among the notable fall drives.
Early October – lower elevations
The foothills, river corridors and lower-elevation communities: Cottonwoods, willows and other lower-elevation trees generally change later than the high-country aspens. Colorado’s typical fall season below 8,500 feet extends from late September into early November.
