Artist Scott Kildall waves his microcontroller over a Joshua tree, recording wavelengths of light that humans cannot perceive.
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Artist Scott Kildall waves his hand over the contours of a Joshua tree, just inches away from its prickly green, bayonet-shaped leaves.
“If I get too close to it, it stings me and makes me bleed,” he said. “And it’s been done before.”
In the palm of his hand is a microcontroller – about the size of a credit card. It has a few wires sticking out and an infrared sensor, which picks up wavelengths of light far beyond what the human eye can perceive.
“It was like magic,” Kildall said. “And the magic is just revealing something that is beyond our level of awareness.”
Magic is part of Kildall’s latest sound installation — a work he calls Infrared reflection. He developed this piece as an artist-in-residence at Joshua Tree National Park this spring, and it turns near-infrared light reflected from the iconic skinny yuccas into a shimmering mosaic of otherworldly music – essentially turning the Joshua tree into a musical instrument.
Kildall is not a computer scientist or musician, although he plays the ukulele. This work of art draws on both principles, as Kildall needed to build the sensors, route their data to a computer, process and smooth that data, and convert it all into something spectacular.
“With art and technology, you have to constantly think about wearing many hats. Are you an IT person? Are you an artist? And you have to be able to fix problems quickly,” he said.
The installation is based on the fundamental interaction between the sun and the Joshua tree. When sunlight hits a plant, the cells in its healthy leaves absorb much of the red and blue light, while reflecting most of the green – which is why leaf clusters penetrating at the end of the branches of a Joshua tree that appears green to the human eye. . (It’s also why most plants on Earth appear green to us.)
Sharp Joshua trees grow in Arthur B. Ripley Desert Woodland State Park, north of Los Angeles.
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But other types of light also rain down on Joshua trees, including wavelengths we can’t see, like near-infrared light. The tree’s rough, gray-brown bark doesn’t reflect much infrared rays, but its healthy leaves — filled with compounds like water, carbohydrates and defense chemicals — reflect more. And that’s exactly what Kildall saw when he moved his sensors from the yucca’s dead bark to its bright green leaf buds.
“Beyond our awareness lies a whole realm of invisible data,” he explains. “And so what I do is find some kind of invisible phenomenon like water quality, air quality, or infrared light reflection, and then map that data into sound so we can get can hear that data.”
That technique is called sonification, and Kildall has previously designed installations The sound of water flowing in the treesor tap into the mushroom’s electrical signal. Infrared reflection follows that vein, but it’s much more location specific – it’s designed to play on Joshua trees, which are endemic to the Mojave Desert.
Kildall needed a speaker and a bag of equipment on site to create his music.
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With that in mind, early this morning, Kildall carried his laptop, box of electronics and giant speaker into a field of Joshua trees at Arthur B. Ripley Desert Woodland State Park, north of Los Angeles. Angeles.
The winds blow across the high desert here and Kildall looks at each Joshua tree with the excitement of a kid at Guitar Center, ready to pick up an ax.
“I saw a Joshua tree about 100 feet away that was shaking a little in the wind and had lots of leaves and bark,” he said. “And that one really looked like it was asking for an ultrasound.”
Kildall’s speaker sat next to some Joshua trees.
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After a short walk, Kildall put down the speaker and began using his laptop. It sat on a camping chair, in direct sunlight, and refused to start — a reminder, Kildall said, of how preparing for a field installation is like planning a NASA space mission. (although stakes are not lethal.)
“You want to reduce the number of failure points. And with the system I have, I have backup electronics, I just have a laptop. So that’s the only point of failure that I’m really worried about.”
But not fear. The machine will soon boot up with a local Wi-Fi network — connecting a small infrared sensor to the computer — and Kildall is ready to go.
View of Joshua trees at Arthur B. Ripley Desert Woodland State Park.
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This is the same landscape seen through a thermal infrared camera. It captures a different part of the infrared spectrum than what Kildall captured with his sensor, but gives a sense of how different these plants look when viewed at different wavelengths of light. .
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As he caressed the air just above the tree, the Theremin’s cry rose and fell from the speakers, creating an eerie soundtrack to the otherwise foreign-looking scene. A few hikers passed by, but didn’t seem to notice the guy performing reiki in the Joshua tree. After all, the high desert is known for its eccentricities.
Kildall designed three additional “instruments” to play like this, along with the Theremin sound.
His preference is to combine the sound of the theremin with spiraling arpeggios.
Another sound sounds more like a haunting electric guitar, echoing in a cathedral.
The final sound is softer and simpler – like a child playing the piano.
“In some ways, it feels a little more direct and accessible because we all understand how to hit random notes on the piano,” Kildall explains. “And when I move the sensor over these leafy spots in the sun, those spots create a higher pitch on the piano.”
As he slid the sensor deeper down the branch, into the bark, the notes got lower and lower, moving deeper into the bass clef.
Kildall held his device a few inches away from the thorny Joshua tree to avoid being stabbed.
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It’s a fascinating way to make music. The infrared sensor technology at the heart of the research is also something that scientists have used for decades.
“From airplanes or our satellites, we use it to separate living plants from dead plants,” said Greg Asner of Arizona State University in Hawaii. “That’s very important in grassland – is the grassland dry and ready to smoke in a fire or is it wet, green and alive? And so we can translate that to fuel grasslands.”
Joshua tree seen through thermal infrared camera.
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Asner also flew above the Amazon basin, measuring infrared signals from the plane – this allowed him to identify individual tree species, based on fingerprints of infrared light emitted from the trees.
“When I flew over the rainforest using infrared sensors, the maps really looked like Willy-Wonka candy store style variation. They are amazing to look at,” he said.
“So there is enormous diversity of plants when you look at them under infrared light. And unfortunately, a lot of people only see them in green because that’s all we can see with our limited eyesight. There is more diversity out there. And it’s a very beautiful world when you look at it in infrared.”
Asner says he’s excited to see artists experimenting with similar technology.
Left: Close-up of Joshua tree. Right: Thermal infrared image of Kildall holding his device in front of a Joshua tree.
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“Our research for decades has been stuck in scientific corridors. And this will help translate what we already understand, use and love as scientists – it will translate it to a wider audience.”
In a sense, Kildall said, that was his goal.
“One of the things I like to do is engage people with nature and climate change and ecological issues through means other than scientific articles,” he said. . “The scientific articles are very good. I read them all the time. However, they don’t engage people on a more visual storytelling level like works of art.”
And although this setting was conceived and developed with the Joshua tree at the center, it could work with the infrared reflections of other trees, if Kildall calibrated his code – which is a good thing, because Kildall calls San Francisco home.
“There aren’t any Joshua trees in San Francisco so maybe I’ll have to go to Golden Gate Park and see what I come up with.”
