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."

September 28, 2009
Arctic warming (it's about more than polar bears)
musk ox1.jpg
Climate change is especially severe in the Arctic - and it's not just polar bears that are feeling the heat. 
That's the conclusion of an article in Science magazine this month (Sept. 09) that combs the scientific literature for information about the ecological impacts of warming in the Arctic - and here are some of the findings: 
  • Unusually early spring rains in northern Canada have led to the melting and collapse of birth lairs of ringed seals, leaving pups exposed on bare ice. 
  • The northward expansion of moths in Scandanavia has led to the severe defoliation of birch forests.
  • Shrub species are moving north, too, threatening plant diversity. But so far, grazing by caribou and musk ox - such as this one I saw in Canada's Northwest Territories in 2004 -  has slowed the advance. 
  • Increased melting of winter snows in Norway has led to a rapid increase in reindeer population, through increased fecundity and less starvation. Elsewhere, less snow-cover has been associated with the collapse of small mammal populations, including lemmings. 
  • Plants are blooming up to 20 days earlier over the past decade in some places.
It makes sense that colder landscapes - those attuned to cycles of snowfall and snow melt - would be among the first to exhibit the impacts of warming. We have one of those landscapes here in California, too - the majestic Sierra Nevada, a glistening white water tower, wildlife sanctuary and recreational bonanza - much of it tied to life around the freezing point. Stay tuned as I explore, in periodic blog posts, the impact of climate change across the Sierra Nevada, California's cold zone. 

September 25, 2009
Sierra Nevada birds and climate change
The more they look, the more scientists find the signposts of climate change across the California landscape. 

In the Sierra, such signals have been detected in more destructive wildfire, earlier spring run-off and the movement of small mammals - such as the alpine chipmunk - uphill toward more hospitable environments. 

A new study - published in the online journal Proceedings of the National Academy of Sciences earlier this month - has turned up more evidence in the behavior of birds, such as the western bluebird, show here.  

The study found that 48 of 53 Sierra species - including the bluebird - have adjusted to climate change over the past century by moving to sites with more desirable temperature and precipitation conditions. 

Some birds shifted to warmer locales while others preferred chillier habitats, the study found. Overall, 82 sites surveyed have seen an average 1.4 degree Fahrenheit temperature increase and nearly a quarter of an inch more rainfall during the breeding season since the early 1900s. The study builds upon the pioneering field work of  U.C. Berkeley zoologist Joseph Grinnell who traveled extensively across the Sierra between 1911 and 1929 and meticulously recorded what he saw. As our climate changes, the study found, birds tend to seek out conditions that existed in habitats - or ecological niches - that Grinnell documented and wrote about in his journals. 

Certain species, such as the Dusky Flycatcher and Green-tailed Towhee were more sensitive to temperature changes, while others, including the Yellow-rumped Warbler and Lazuli Bunting  reacted to precipitation changes. About a fourth of the species studied responded to both temperature and precipitation. 

"Understanding how species will respond to climate change allows us to take steps now to restore key habitats and create movements corridors that will help them respond to the changes we have coming," said Morgan Tingley, lead author of the study and a Ph.D. student at U.C. Berkeley, in a press release. 

To read the actual paper, click on this link:

Photo courtesy of Morgan Tingley

September 8, 2009
A modern-day Johnny Appleseed
Tree-planting is popular these days but few people know more about it - or do more of it - than Mike Landram, regional silvaculturist for the Forest Service in California. 

Today, Mike is being award the John R. McGuire Award - named for the former Forest Service Chief who helped draft the National Forest Management Act - for his efforts to replant large patches of California forests burned by increasingly high severity wildfire, including the 2007 Moonlight fire in the northern Sierra.

Tree planters don't get enough kudos. They are the care takers of tomorrow, custodians of the forests that your children's children will enjoy later this century or early next. But restoring forests in an era of climate change is not simple. Late last year, I talked to Mike about some of the challenges - and during our conversation his passion for reforestation was clear. Here is some of what he told me:

"I think the Forest Service has a fundamental obligation to keep forest land forested. Aren't these forests in a public trust because they're forests?"

"The thing I worry about most are the big, burned out patches. They are not characteristic in an evolutionary sense...."

Because such fires inflict so much damage, tree-planting efforts are critical, he said. Nature needs an assist. But as temperatures rise, planting strategies need to change.   "The good news is that most of these planted trees are reasonably able to adapt to changing conditions once they get established. But if we think the temperature is going to increase six degrees - and we know the place we are working is already at the warmest edge of where it will grow - don't bother to plant it."

Instead, plant what you expect to grow there in the future. "We call that assisted migration," he said. "That is something the reasearch community is aimed at trying to help us to do."

Change is inevitable.  Forests today don't look like they did during the Gold Rush. "We can rest comfortable that the future will be different than today," Landram said.

But the important thing, he said, is to do something.... to plant a tree. "We as a society usually want to focus on the controversy of the day - not on the kind of forest we are going to create for future generations. And we lose focus on what kind of legacy we are leaving the next generation." 

To read more about Mike and his award from the National Association of Forest Service Retirees, click on this link:

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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