The days are getting shorter, the nights a bit cooler, late season wildflowers have bloomed and many have gone to seed. Not only that, patches of aspen are already showing off their autumn colors. Many are predicting aspen colors to peak early and have muted color this year because of the drought. True?
The short answer is maybe. The standard line of thought is that when there are severe drought conditions during the growing season, a line of cells along the junction of the leaf and stem begins to form earlier than usual. This layer of cells, called an abscission, blocks the flow of sugars from the leaf and nutrients to the leaf. It also, blocks the movement of chlorophyll into the leaf.
Chlorophyll, which provides the green color in leaves, has a limited shelf life and fades when its supply chain is cut off. As the green disappears, the more stable yellow and orange colored pigments below are exposed providing the autumn color we all enjoy. Some say these pigments aren’t as brightly colored during drought years, so not only would the leaves change early, but their colors wouldn’t be as vibrant.
Last winter’s snows were meager and melted off early, and this year’s monsoons were on the light side. In fact, this is the 4th driest year in the upper Rio Grande since 1890 based on river flow data. So, does this mean we should expect an early color change with dull colors? Maybe. I readily admit my memory isn’t the best, but as a photographer, I pay attention to fall colors. And in 2002, our driest year since 1890, I don’t recall a significantly early change in fall colors.
Temperature also plays a role with how early the trees turn color, and temperature and wind impact how quickly the leaves fall off. And since it is difficult to accurately predict the weather further out than a week, I would argue it is hard to predict what is in store this year.
One thing I know for sure, though, is that there are many excellent areas in the upper Rio Grande watershed to catch the autumn colors. One of my personal faves is the Silver Thread Scenic Byway running along Highway 149 from South Fork to Lake City. The aspen along this route often peak around the third week of September. If you have moderate clearance on your vehicle, I would also recommend taking a side trip up Forest Service Road 522, the Fern Creek Road, into the Papoose burned area. The aspen that sprouted after the fire are thick and six feet tall.
There are many options for catching the fall colors on the Saguache Ranger District. Adventurous folks with four-wheel drive would certainly enjoy a trip up Kerber Creek and then jump off onto FSR 880 before reaching Bonanza and looping down Findley Gulch to Highway 114. This route passes through a variety of forest types, including aspen stands, while also mixing in some views of old mines.
The classic autumn driving route on FSR 250 in the southern part of the Forest is hard to beat. This route runs through extensive aspen stands in both Alamosa and Conejos Canyons. The photo opportunities are especially good in Conejos Canyon with many of the aspen stands positioned right below rugged cliffs.
While Colorado’s aspen typically get all the attention in the autumn, don’t forget to check out the beautiful color change among the sedges, shrubs and herbaceous plants. I often point my camera down and focus close to photograph the reddish purple leaves of fireweed, the orange three-leaf sumac, and the red berries against yellow leaves of red berry elder.
Autumn is such a special time of year and while it is fun to catch the big views while driving, I would argue that it is even better to get out of your car and stretch your legs a bit on a walk. I find I take my best photographs when I slow down.
Mike Blakeman is the public affairs officer for the Rio Grande National Forest. He spends much of his free time scrambling around the mountains with a camera in his hand.