Huffington Post - Dominique Mosbergen
Two Stanford researchers have transformed data of a dying Alaskan tree into song.
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| Yellow cedar trees are shown in abundance in
Glacier Bay National Park, left. The image on the right, south of the
park in the Tongass National Forest, reveals the impact climate change
on this tree. Lauren Oakes |
Quick, bright piano notes open the melody. It's lively,
almost playful; conjuring images of birds chirping through sun-dappled
forests.
Then suddenly, a shift. The piano notes quieten; the
silence interrupted only by the lament of a lone flute. But soon, other
instruments compete for the listener's attention, the strings and a
clarinet jostle to be heard.
The piece becomes a roller coaster of sound and emotion,
until finally it ends with a trill of a flute — almost abruptly— much
more subdued than how it began.
This is a 100-year-old story captured in a 3-minute song;
the story of a dying tree and its changing forest home. It's a song
about life and death. It's a song about climate change:
Two Stanford researchers collaborated to create the music through an emerging analytical tool known as
data sonification. It captures the ecological transformation of
Alexander Archipelago, a 300-mile chain of islands off the southeastern coast of
Alaska.
There, yellow cedars have been dying in staggering numbers over the
past century. Other trees have been moving in to take their place.
The piano in the song represents the dying yellow cedar; violin and
viola symbolize mountain hemlock; the clarinet is shore pine; cello and
bass are Sitka spruce; and western hemlock, the conifer which has
successfully usurped the cedar in some swathes of the archipelago, is
played by the mournful flute.
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| Dead yellow cedar trees on Chichagof Island in the Tongass National Forest. Lauren Oakes |
Yellow cedar has long been a culturally,
ecologically and economically valuable tree in southeastern Alaska. Many
of the trees are ancient, aged between 700 and 1,200 years old. Their
leaves and surrounding soils play host to unique bacterial communities;
animals rely on the trees for food and shelter, while humans prize them
for their durable, closed-grained wood.
For the past 100 years, however, the yellow cedar has been
dying off in large numbers across Alaska and British Columbia. As of
2012, 60 to 70 percent of yellow cedar in a 600,000-acre area in the
region have died.
Climate change is to blame for this die-off, scientists
say. They've concluded that though the trees could withstand centuries
of bugs, rot and injury, their shallow roots are
vulnerable to freezing when the surrounding soil is not protected by a layer of insulating snow.
Alaska has been
melting for decades. The average temperature across the state has increased by about 3
degrees Fahrenheit over the past 60 years. That's more than twice the
warming recorded in the rest of the U.S., according to the Environmental
Protection Agency.
Interested in these dying cedars and, more specifically,
the environmental changes that the tree deaths had triggered, ecologist
Lauren Oakes visited the Alexander Archipelago in the summers of 2011
and 2012 to conduct field research. Oakes, then a doctoral student at Stanford's Emmett Interdisciplinary Program in Environment and Resources, started
in the north of the archipelago in Glacier Bay National Park where
healthy yellow cedar forests still thrive. She steadily moved south to
areas increasingly afflicted by warming temperatures and dying cedars,
finally ending her research at the base of Slocum Arm in the remote
wilderness of the Tongass National Forest.
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| Oakes' field crew during their Alaskan research expedition in 2012. Lauren Oakes |
Wherever Oakes and her team of field
assistants went, they identified trees and other plants in the forest,
taking note of measurements including the height and diameter of each
specimen. Her data set ended up containing nearly 30 variables for more
than 2,000 conifers. Oakes published her findings in an article for
the journal Ecosphere in 2014. But as with most academic writing, it was not widely-read beyond a select group of academicians.
That didn't sit well with Oakes.
"My path in life
to date has been at the intersection of environmental research and
communications — so I'm always looking for interesting ways to share
important stories of environmental change with a broad public," she
shared with The Huffington Post in an email last week.
Oakes double-majored in environmental
studies and visual art, specializing in film and photography, at Brown
University. She later worked on a series of environmental documentaries,
including one for PBS' Frontline, and wrote
for The New York Times Green blog. She recently began work on a book about her Alaskan research for a mainstream audience. It's due to be published in 2018.
"In any project I tackle, I want to
publish the research in journals for the science community, [but also]
work to communicate what I learn through other creative means to a
broader public," she said.
So when Nik Sawe, then also a PhD student at Stanford, emailed her earlier this year about his pioneering work in data sonification, Oakes said she was instantly intrigued and replied immediately. Sawe had been looking for interesting datasets to sonify.
Data sonification is, essentially, the
transmutation of data into music. It involves a computer and a composer,
who feeds information into a special modeling software that
reinterprets data so it'll make sense to a musical instrument digital
interface, or MIDI.
Similar to the more mature tools of data
visualization, sonification is meant to help uncover or better explore
patterns and trends. These patterns, in turn, could unveil news way to
see the world.
The tool is still in its infancy, but
many interesting sonification projects have already emerged. Musician
Brian Foo has sonified
income inequality in New York City and
air quality in Beijing. Chris Chafe, director of the Center for Computer Research in Music and Acoustics, Stanford's computer music research center, and a mentor of Sawe's, has sonified electrode recordings
from epileptic patients.
And then, there's the climate change
music — the result of the sonification of Oakes' data from Alaska. The
music maps Oakes' journey from the healthy cedar forests of the north to
the dying ones of the south. "What I was really looking for was not
just a pattern but a narrative," Sawe said. "The decline of the yellow
cedars and the link to climate change was a very clear story in the
data. The trick was trying to represent that in audio."
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| Yellow cedars in Glacier Bay National Park, left, and in Tongass National Forest. Lauren Oakes |
Then Sawe realized that Oakes' trip had, in effect, been a journey back in time.
"As Lauren went further south along the
Alaskan coast, the forests had been wrestling with climate change for a
longer time. So that travel through space, from north to south, became
time in the song. We first hear the forests in the north — still largely
untouched by climate change — and as we travel south the changing
landscape becomes more and more evident," he said.
Every moment in Sawe's composition is
meaningful. Every note is a tree and every species plays a different
instrument. The pitch of each note is related to the height of the tree;
how hard the note is hit is linked to the diameter at the base, and the
duration correlates to tree health.
"We spend the same amount of time in
every place that Lauren visited, so if there are say, 40 yellow cedars
in one location, they'll play very quickly and lively; if there are 3,
they'll be long slow notes," Sawe said. "But here's perhaps the most
important part of the mapping: dead trees count as silences. So in a
place with 3 live trees and 30 dead, we'd hear 3 sporadic notes
surrounded by silence. And that's why you can really hear, about midway
through the song, this abrupt change in the liveliness of the yellow
cedar. More and more of the trees in the forest are dead."
In the recording below, the yellow cedar's piano melody is
isolated, allowing for closer listening to the individual tree. Note
the silences that begin near the middle of the song:
Sonification of data
involves a precise, scientific process — but there's artistic flair
intertwined in it too. In the case of the Alaskan forest
composition, for instance, Sawe made two obvious aesthetic choices. One
was the use of cello and bass to represent Sitka spruce, which is a tree
whose wood is often used to make stringed instruments.
The other was the key. "I picked D minor as it sounded rather poignant," Sawe said.
The song seems to take on an elegiac
quality as a result, a ballad to the dying cedar tree. But a different
key could've perhaps reflected something else Oakes discovered in her
research.
"This is a story of death, yes, but it's also a story of
regeneration, and a new forest community taking shape," she said. "In
the song, you hear yellow cedar trees drop out and then other species
regenerate. In the middle, you hear a busy flurry of instruments as
various species compete to regenerate. Then over time, in the end, you
hear more flute ― Western hemlock dominates."
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| The outer coast of Glacier Bay National Park where yellow cedar trees still thrive. Lauren Oakes |
Sonification could change the way scientists, and the public, analyze and appreciate data.
"For scientists to interpret their data
in a new way, this could be really valuable," said Sawe, who is
currently working on another research project at Stanford to sonify
California's drought. "In terms of how we explore our data, and what
questions we ask next as we endeavor to do good science, this is a
really promising tool."
The accessibility and emotiveness of music means that broader audiences can also be reached ― and touched.
"You don't have to understand statistics or how to read a
graph, you don't need access to an academic journal, you don't have to
dig through the raw data where Lauren painstakingly recorded the
attributes of thousands of trees. I can describe what you're about to
hear in 20 seconds and then you've got it, and you're able to hear every
single tree that Lauren visited down the Alaskan coast inside of 3
minutes," said Sawe, adding that the emotional quality of music allows
for listeners to experience data "viscerally."
Next spring, a live orchestra will be
playing Sawe's climate change composition on Stanford's campus. He and
Oakes, now both lecturers at the university, say they hope to also
launch a public exhibition that will showcase the music as well as the
photos Oakes captured in the Alaskan wilderness.
"I'd like our work to communicate science
in a more accessible way and for it also to help raise awareness about
the kinds of impacts occurring as a result of climate change," said
Oakes. "As Nik would tell you, information alone isn't often enough to
motivate action. Feeling motivated is often connected to emotion, and we
tend to strip emotion from science."
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