Leaf-peeping might not be quite as brilliant due to leaf blight | AspenTimes.com

Leaf-peeping might not be quite as brilliant due to leaf blight

Pockets of trees in the Slate River Valley outside of Crested Butte started hinting at fall late last week.
Scott Condon/The Aspen Times |

My wife, Ann, and I made a 500-mile sweep through the central mountains of Colorado last week and couldn’t help but notice the sickly appearance of swaths of aspen trees.

Rather than looking a healthy green or changing to the vibrant yellow or reddish color, the leaves are a dull brown on patches of trees on the Twin Lakes side of Independence Pass, on Monarch Pass and on Kebler Pass.

The Colorado State Forest Service identified the culprits as leaf spot diseases that proliferated in the wet spring and early summer.

“For about the past month, foresters have been seeing an unusually high degree of leaf blight in the mountains and along the Front Range, as far south as Aspen, the Collegiate Peaks and Colorado Springs,” said a statement issued Sept. 8 by the state forest service.

Leaves of aspen and cottonwood trees are being affected by at least two fungal diseases, the statement said. They cause leaves to get dark brown spots or flecks on the leaves. They fuse into large, black splotches that engulf the entire leaf on severely affected trees, the forest service said.

Some of the blight’s effects are visible on cottonwood trees lining the Roaring Fork River in Snowmass Canyon.

The blight will affect leaf-peeping to an unknown degree this year but trees won’t suffer long-term consequences, the forest service said.

And fortunately, it won’t affect all leaves this year. On our tour, we estimated only about 5 percent of leaves have already turned, as could be expected in early September. There were brilliant pockets that exploded into yellow around Twin Lakes, mostly on north facing slopes but also high on Mount Elbert.

An obscure road between Doyleville and Pitkin in Gunnison County teased us with occasional flashes of yellow and rust in an otherwise thick sea of green aspen leaves and conifers.

Slate River Road outside of Crested Butte was just starting to show signs of turning.

The leaf blight was most noticeable on the lower elevations of Kebler Pass, a renowned destination for leaf-peepers. The upper half might still turn out to be as brilliant as ever, but we witnessed a lot of a dead and dying leaves on trees at and below the Ruby Anthracite Trailhead.


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