Sierra Summit

Conversations and observations about California's mountains

September 29, 2009
Alpine wildflowers and climate change
sky pilot.jpg
Some of the prettiest wildflowers you'll ever see in the Sierra Nevada grow above timberline, including this wonderfully-named Sky Pilot, which I photographed at 12,500 feet above sea level at the Middle Palisade glacier near Big Pine earlier this month (Sept. 09)

The Sky Pilot is also emblematic of a rugged, windswept and starkly beautiful ecosystem that is now in danger because of global warming.

"As the climate gets warmer, the tree-line moves up," Ann Dennis, a retired vegetation ecologist with the U.S. Forest Service told me in an interview. "If tree-line goes all the way up to the top of the mountains, there will be very little habitat left for these species."

The risk is more acute in the northern Sierra, including the Lake Tahoe region, because  forests already creep close to the summits in many places, she said. "The alpine zone is really just a tiny little slice at the top of the peaks. Once the trees get up to the top of those peaks, there really isn't going to be habitat in the Tahoe area for a number of species."

Dennis is working with the Global Observation and Research Initiative in Alpine Environments, or GLORIA, for short ( to study changes in the alpine zone. Research is underway in the Sierra Nevada and White Mountains and more information can be found at:

"I think it is a very genuine cause for concern," Dennis told me. "I care, personally, because I love the high mountains. And I have been going up to very high places since I was a little child. My heart sings in these places. I love it."

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About Sierra Summit

The Author
Tom Knudson lives in the Sierra Nevada and travels widely throughout the range. His hobbies include fly-fishing, backpacking and cross-country skiing. He is the recipient of numerous journalistic awards, including two Pulitzer Prizes, one for a 1992 Sacramento Bee series "Sierra in Peril," a watershed work about environmental threats to the mountain range. E-mail Tom at

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