My five favorite tree locations: the diversity of tree sounds
(1) A maple twig in suburbia: sonifying the heartbeat of a tree.
Twigs have a daily heartbeat as water pulses through them. I measured this 24-hr cycle with a sensor, then used a computer to make the cycle audible to human ears. We hear the twig’s diameter changing in the notes of an electronic piano. The fatter the twig, the higher the note.
One 24 hour period. The twig is full of water at midnight (high notes), then shrinks after sunrise as water starts to flow and draws the twig inward (lower notes). Last, the twig rehydrates in the evening and early nighttime (notes rise again):
A multi-day sequence. The overall pitch increases because in addition to its daily pulse, the twig is adding new wood each day, getting wider:
(2) Sounds recorded from a very high treetop in the Amazon rainforest. The mind-blowing diversity of the forest breaks forth in sound at dawn: monkeys, birds, insects.
Below, plant diversity is manifest in the varied sounds of rain falling on leaves with radically different shapes, like a collection of botanical drumskins:
(3) The sounds of the city, flowing up from the ground into the wood of a street tree in Manhattan. These vibrations become part of the tree, causing it to grow different kinds of wood. The tree in turn then changes the texture of the soundscape of the street. I made this recording using an accelerometer run through a sound digitizer. We hear the subway (vibrations coming up through the ground) and the sound of a sparrow (vibrations arriving in the air):
(4) What the roots of a palm tree on the beach experience. I recorded this with a hydrophone. Rapid erosion was eating away the sand around this old palm tree. Shortly after this recording, the palm was felled by a spring tide.
(5) Sounds of the fierce mouthparts of a thumb-sized beetle larva chewing wood inside a dead tree. You can also hear the beetle’s mortal enemy: tapping of hairy woodpecker further along the trunk.
Additional sounds and soundscapes from the trees:
Sabal palm, St Catherine’s Island, GA:
“…walking on fallen fronds we hear volleys of cellulosic guns, the crackling breakage of hundreds of stiff bonds.” Recorded as my students walked under the sabal palm:
“atonal panic, sensory tumult that overwashes all else … Prospero’s rough magic and roaring war.” The sound of storm and high tide at the base of the sea-felled palm. This recording captures the tumult, but the lowest frequencies (felt in my chest rather than heard in my ears) cannot be conveyed through mp3s:
“I scoop some foam into my hands and thousands of bubble surfaces pop as I lift them, a sizzle like fish frying in a pan. The smell of foam is a distillation of ocean, like an inhalation after diving through a collapsing breaker, head wet with spray.” Sea foam recorded under the sabal palm. To record this quiet fizzle, I scooped foam into my hands then ran up the beach to shelter under the trees and thus get away from the overpowering sound of the waves. I held the microphone a few millimeters from the foam:
Ponderosa Pine, Colorado:
“I strap a thumb-size ultrasonic sensor to a ponderosa twig and wire the electronic device to a computer. Then I wait, “listening” through the intermediary of a graph on the screen. Every time the twig releases an ultrasonic pop, the graph’s line jolts up by one step.” The sound sample below comes from a well-hydrated twig gradually drying. I converted ultrasonic data into audible “clicks.” As the twig dries, the rate of clicking increases. The 41 second sound sample is a compressed version of about 12 hours, a morning (when water is more plentiful) through the afternoon (when dryness increases, then eases as the sun sets) on one day:
Mitsumata, Echizen, Japan:
“I stopped at mountain water, at a pool of cool ablution. The craft of papermaking takes the same route: we cannot make paper without first dipping into cold water.” Washing hands at Kawakami Gozen’s shrine:
“I passed through the torii gate onto gold-leafed flagstones, spent ginkgo softening footfall to the kami’s shrines.” Sounds of fallen ginkgo and Japanese cedar leaves underfoot:
Hazel, near Edinburgh, Scotland:
“The tree’s remains are swathed in plastic and enclosed in a cardboard sarcophagus. The archival box is marked with sample and location codes. Inside, labeled sacks keep order: Charcoal, Bone, Nutshell.” The sound of an archaeological storage bag opening, then 10,000 -year-old nut shells sluicing out onto a petri dish:
Cottonwood, Denver, CO:
“Puffs of wind set the cottonwood tree tapping, hard leaf edges batting one another. Stiffer wind brings slaps as the waxy leaves strike with glancing blows. These are the sounds of a fast-growing cottonwood tree. Despite the heat and low air humidity, the slap of the leaves reveals their full hydration.” Cottonwood leaves recorded at Confluence Park, Denver. In the background, South Platte River flows over the South Platte river weir and Denver traffic noise:
Olive, Israel and the West Bank:
“The olives here are young trees of new varieties, bred to grow fast and yield much oil. A harvesting machine as tall as a house — a modified grape picker — straddles the rows and roars as it thrashes olives from twigs to hopper.” Olive-picking machine working down a row of young olive trees in a plantation in Israel:
Japanese White Pine, Japan and Washington DC:
“Trees in Miyajima grow surrounded by the sound of prayers. In front of shrines, wooden balls the size of oranges are threaded onto loops of rope that pass over pulleys mounted to the shrines’ doorways. When pilgrims haul the ropes, the balls rise with the rope, then overtop the pulley and fall against one another, clacking and delivering a sonic petition to the shrine deities.”
“…kindled a gas flame amid the cenotaphs and mass graves of the city’s Peace Park.” The sound of the Flame of Peace at Hiroshima Peace Memorial Park, with the Children’s Peace Monument memorial bells ringing in the background:
Balsam fir, boreal forest in western Ontario:
“A forest’s intelligence emerges from many kinds of interlinked clusters of thought. Nerves and brains are one part, but only one, of the forest’s mind.” Bird song in the boreal forest in summer. Recorded next to the balsam fir:
Green ash, Sewanee, Tennessee:
“The tear in the canopy caused by the tree’s fall created an inverted geyser of light. After a year under the abundant flow of photons, what were small herbs have turned into bushes.” Hooded warbler and others singing from dense undergrowth along the fallen ash’s trunk:
David George Haskell 