Aspen Autumn Color in Colorado

Old Buildings with Golden Aspen. Shawnee, Colorado

We were in Denver last week, visiting my parents. Since it is fall, we took several trips into the mountains to see the yearly color show in the mountains. In early fall, the shimmering leaves of the aspen, the quintessential Colorado tree, turn to a positively glowing shade of gold, sending locals and visitors rushing to the mountains. The glorious colors don’t last long, however, usually from mid-September to the beginning of October. On this trip we followed the North Fork of the South Platte river out of Denver to Kenosha Pass on Route 285. The trip goes by fairly quickly, only about hour and a half to the summit of Kenosha Pass. The photo above was taken in Shawnee last week.

Map of the Area of the North Fork of the South Platte River, Colorado

North Fork of the South Platte River near Bailey, Colorado

Brook Trout from the North Fork of the Platte River. Courtesy of MileHighAngler — Brook Trout from the North Fork of the Platte River. Courtesy of Mile High Anglers

Cutthroat Trout. North Fork of the Platte River, Colorado

The North Fork of the South Platte River is a tributary of the South Platte River, approximately 50 miles (80 km) long, in central Colorado. It rises at the continental divide on the eastern side of legendary Kenosha Pass. The North Fork is extremely small and expeditious for the first several miles until it joins forces with diverted water from the bottom of Dillon Reservoir via the Roberts Tunnel. Another tributary, Geneva Creek, further adds a substantial quantity of water to the North Fork near the small town of Grant. Downstream from Grant it is followed by U.S. Highway 285 until Bailey, where it cuts through a remote section of the foothills. It joins the South Platte from the west at the lower end of the Platte Canyon in the mountains approximately 20 miles (32 km) southwest of Denver. The area around Guanella and Kenosha pass is particularly good for sightseeing during the fall color show of the aspen. The North Platte is also home to excellent fishing both in public areas and on private ranches.

Golden Aspen in October. Kenosha Pass, Colorado

Yellow Aspen in October. Shawnee, Colorado

Aspens make up about 20 percent of Colorado's forests and usually are found between 6,900 feet and 10,500 feet in elevation. The golden color is actually always on the leaves, but chlorophyll production in the long days and bright sunlight keeps them green. As the days shorten and nights get cooler, chlorophyll production slows and a membrane forms between the branch and leaf stem. The green color fades and the golden leaf eventually drops to the ground.

Golden Aspen in October. Shawnee, Colorado

In some regions, such as New England, a few tree species dominate the forests and the color change tends to be rapid and uniform. But anyone who has gone leaf-peeping in Colorado knows, while one area might be a blaze of gold by the third week of September, in the next valley over the leaves might be green or already dropped. The reason is aspens are clonal, from a handful to several hundred trees all sharing the same root system. In fact, some aspen groves rank as the largest single organisms on the continent, though there are some fungal colonies that compete for that title. In the picture above, you can see green Aspen from one root system in front of a riot of yellow Aspen just behind.

Kenosha pass was used by Ute bands to reach the hunting grounds of South Park on the west side of the pass, headwaters of the South Platte. In the 19th century the pass was used by white trappers to traverse the Front Range. During the Pike's Peak Gold Rush of the 1860s, the pass was heavily used by prospectors eager to reach the placer gold fields at the headwaters of the South Platte near Fairplay and other South Park mining communities. In 1879 the pass was traversed by the narrow gauge Denver, South Park and Pacific Railroad, providing the first rail link between Denver and the South Park mining communities such as Fairplay. The tracks were removed in 1938, but the modern highway follows the old road and the railroad route over the pass, most of which is still visible. During this same year of 1879, the poet Walt Whitman crossed the pass and described its summit with these words, later published in Specimen Days:

I jot these lines literally at Kenosha summit, where we return, afternoon, and take a long rest, 10,000 feet above sea-level. At this immense height the South Park stretches fifty miles before me. Mountainous chains and peaks in every variety of perspective, every hue of vista, fringe the view…so the whole Western world is, in a sense, but an expansion of these mountains.

Mount Bierstadt and Mount Evans. Kenosha Pass, Colorado

In the distance you can see Mount Bierstadt and the slightly higher Mount Evans behind it. They are two of 54 fourteeners (mountains with peaks over 14,000 feet (4,300 m) in elevation) in Colorado. It was named for Albert Bierstadt, a popular painter of Colorado's Rockies of the 19th century. The most popular base from which to begin ascent of Mount Bierstadt is Guanella Pass, located to the west. Guanella Pass connects the tiny town of Grant to Georgetown.

Idaho Springs Waterfall with Turning Aspen. Idaho Springs, Colorado

The next day we saw the turning leaves at the Idaho Springs Waterfall on Interstate 70 on the way to Georgetown. I decided to include it here, in the mountain color post. The waterwheel beside the falls is from the 1800's. The mountain aspen are in full “bloom” right now, if you are in Colorado or planning to visit, don't miss this beautiful sight.

References:

Shawnee History: http://www.historicshawnee.com/