Alpine Tree Study Points to Climate Change

http://www.idahopress.com/news/?id=7692
Idaho Press-Tribune
Monday, April 21st, 2008

Tree study points to climate change

POCATELLO – Trees are now surviving at heights in the Intermountain
West where scientists previously said they couldn’t.

For the past 13 years, Idaho State University associate biology
professor Matt Germino has planted evergreen seedlings on regional
mountain tops, and the evidence he’s gathered by studying them shows
significant change in Idaho’s climate.

The speed at which a long-standing rule of nature seems to be
breaking down is hard to fathom, even for a researcher who seeks the
evidence.

When he started his alpine study in 1995, Germino’s seedlings
required man-made structures designed to bump up the temperature to
live in the windy and cold conditions above the tree line.

But in more recent years, the seedlings have grown fine without help.

Though there are still many who refute that human-caused global
climate change is occurring, all of Germino’s data on trees growing
now at higher altitudes in Idaho are consistent with the theory.

The tools of science

Scientific instruments and a spiderweb of wires covered the baked-mud
infield of the baseball diamond by ISU’s new Rendezvous Center.

On a breezy Monday afternoon, the propeller of an anemometer – a
device used for measuring wind speed – whirled steadily, sending data
to a computer system inside a metal box. The computer also
simultaneously recorded radiation levels and 70 different temperature
readings relayed by the wires.

Several of the wires ran below coffee table-like inventions with
clear, Plexiglas surfaces. Germino, an athletic 37-year-old with
short brown hair, designed the structures to mimic the effects of
global warming.

“This is the guts of experimental climate change research,” Germino
said, surveying his project.

A few of Germino’s tables had flat, clear surfaces designed to
magnify the infrared radiation enough to generate an extra 30 watts
per meter squared of radiant energy.

Other devices researchers use to replicate global warming are
cumbersome or require electricity. Germino’s tables, however, are
cheap to make, easy to transport and particularly useful in remote
areas.

Since 1995, when he started climate research at tree lines within the
Snowy Range of Wyoming, the design has served Germino well. But he
pointed out one major deficiency: The solid, flat top doesn’t allow
rain or snow to penetrate to the seedlings covered by the structures.

To remedy the flaw, he’s designed a new table in which the radiation
is intensified through a series of thin strips of Plexiglas laid out
like Venetian blinds. As basic as the design is, it’s an innovation
years in the making for Germino.

“I actually thought about patenting it, but I want people to use it,”
Germino said.

An undergraduate student specializing in plant physiology, Dennis
Demshar, built 24 of the flat-top tables last summer and is helping
to build 24 more with the new, louvered design.

Last summer’s experiment covered various elevations of Fred’s
Mountain, located in the Tetons above Grand Targhee Ski Resort, with
896 subalpine fir, Englemann spruce and whitebark pine trees. Some
seedlings were covered by the tables, and others were cooled by a
special plastic designed to filter the long-wave radiation that
carries heat. Control groups of seedlings were planted in the open.

It’s an ongoing study that will likely last for years. Germino said
it’s gotten international recognition, and new mountain ranges
throughout the West are being added to the study all the time.

“If you change any little thing about the surrounding microclimate of
a plant, it’s going to have drastic drawbacks to it,” Demshar said.
“There’s been a lot of talk that in the next 100 years, global
warming could change the temperature by 5 to 7 degrees.”

On a personal level, Demshar’s research experience has also helped
him identify a career path.

“Any time anyone can be involved in a novel procedure it is really
good because you are working on this big global mindset which is
science, and it’s all moving forward,” Demshar said. “Me happening to
be an undergrad, it is just amazing, and it is a huge opportunity. I
love it. It has really solidified in my mind that I want to be in
science.”

The Snowy Range

Historically, trees in this region haven’t fared well above 10,000
feet due to the stress posed by the combination of nighttime frost
and intense daytime radiation.

It’s at night when global climate change most affects alpine tree
survival, Germino explained.

“The least ambiguous symbol (of global warming from my studies) is in
that nighttime minimum temperature,” Germino said. “The increase in
tree seedlings in the alpine with warmer nighttime temperatures is an
early bellwether of future ecosystem responses to warming.”

When Germino started his research in the mid-1990s at Wyoming’s Snowy
Range, there were only about five frostless nights throughout the
summer in the alpine. And about 99.5 percent of seedlings that
sprouted in such conditions died within the first few months of
germinating.

After a careful examination of alpine meadows in the range, he
observed 2-inch seedlings somehow managed to survive by the bases of
larger “nurse” trees. Germino hypothesized the nurse trees helped the
seedlings in the daytime by casting shadows and at night by radiating
heat. In those days, Germino found that a single degree of extra heat
could reduce the occurrence of nighttime frost by a third.

So he packed in his heating tables and a bunch of seedlings and
sought to mimic the scenario away from a nurse tree by manipulating
the temperature by a single degree.

The experiment worked as predicted.

When Germino returned to survey his seedlings, the ones he planted
beneath the heating tables, which simulated the nurse trees,
survived. He also planted several exposed seedlings, which all
perished.

In the summers of 2002 and 2003, Germino returned to the Snowy Range
to study the fungi in the soils. Less than a decade had passed, but
he dealt with frosty nights only 5 percent of the time during both
summers.

In 2007, Germino repeated the Snowy Range experiment with Demshar in
the Tetons. Again, the seedlings under the heat tables survived. Only
this time, many of the trees they planted in exposure also lived with
no augmentation whatsoever.

“They didn’t care. Low temperatures were no longer restraining the
seedlings from growing in the alpine,” Germino said. “We put the
treatments on them, and they hardly had any effect. Where the tree
line is now, there’s no longer much of a temperature restraint for
seedlings to establish.”

A warning from the Douglas fir

One of Germino’s doctoral students, Sheel Bansal, planted 500
evergreen seedlings on Fred’s Mountain above Grand Targhee Ski Resort
in 2005 seeking to collect data about how trees utilize carbon
dioxide at various elevations.

But the most eye-popping aspect of the Ph.D. student’s research had
nothing to do with the intended subject matter.

Bansal planted Douglas fir and subalpine fir seedlings at both 8,000
feet and 10,000 feet. Conventional wisdom suggests Douglas firs
shouldn’t survive above 9,000 feet in that region.

He fully expected colder temperatures would make short work of the
Douglas firs he planted higher up.

Bansal was somewhat startled when he returned in late 2005 and saw
they were thriving. And after the snow melted in June of 2006, about
as many Douglas firs as subalpine firs were still there. He
eventually pulled the saplings up because his experiment was over.

Germino called his student’s findings a “jaw dropper.”

“I was stunned. I didn’t believe the data at first,” Germino said. “I
was like, ‘You sure you got these species right, because they look
kind of similar.'”

Bansal argues the Douglas fir’s ability to survive at new heights is
a clear, local indicator of climate shift with great long-term
ramifications for the ecosystem. He noted, however, it could take a
long time for the distribution of tree species to change because
trees grow so slowly at high elevations.

“Kind of by seeing Doug fir grow so well up there, what that could
imply is that the temperatures have already changed to favor a shift
in the communities, but we just haven’t seen the plants catch up
yet,” Bansal said. “If the Doug fir comes to the top, the subalpine
fir is going to have nowhere to go, and the whitebark pine is going
to have nowhere to go.”

Eventually, he said the shift could result in extinctions. In the
short term, Bansal believes the story told by fir trees should serve
as a warning that if society fails to change its ways, other dramatic
changes could be on the horizon.

Spreading the word

Germino’s discoveries have been published in about a dozen trade
journals and have passed the litmus test of peer review.

On Friday, he presented some of his findings in Boston at the
American Association for Geography’s Special Session on Climate and
Alpine Treeline Feedbacks.

His research was corroborated at the forum by eight separate
presentations from colleagues throughout the Rocky Mountains. They,
too, reported an increase in tree establishment in the alpine.

“All of our data collectively are beginning to really paint the
picture for us,” Germino said.

Germino is also collaborating with scientists from other research
institutions to unravel a complex issue that’s finally gotten the
world’s attention.

He and some researchers from California have a $1 million Department
of Energy Grant for an experiment involving heat lamps in the
Colorado alpine.

He’s also assembled a team of top experts in paleoecology – the study
of past ecological change – from the University of Arizona and the
University of Washington. By examining tree rings, they’ll help
Germino look back in time to get a better picture of treeline
responses to climate.

“We’re hoping to learn more about this from the whole Western U.S.,”
Germino said. “Just in the time I’ve been doing this, there’s been a
pretty substantial warming trend. The disruption is an opportunity to
learn more about plant communities.”

And of course, he’ll continue climbing the region’s tallest peaks to
study the treeline, using his rudimentary heating tables to advance
our understanding of what is possible in climate science.

To Germino, trees and plants are an underutilized canary in a coal
mine. The data they convey gives him no cause for trepidation, high
as the stakes may be. He stops short of classifying the looming
change as either good or bad.

He’ll tell you he’s a researcher, and there’s never been a more
exciting time to study the climate.

http://www.idahopress.com/news/?id=7692

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