Eavesdropping on thirsty trees

Loose Leaf Blog:

It’s long been known that cavitations — air bubbles that block the flow of water throughout the tree — make a sound that can be heard with a microphone. If too many of these cavitations occur, such as we might see in drought conditions, a tree can die.

The problem is that the sounds of cavitations, among other tree activity, are outside our usual range of hearing and can only be heard with the proper equipment. Then, the question of how to tell which sounds are indicative of cavitations — and therefore early warning signs of drought stress — was a bit of a doozy.

Until now. A team of scientists from Grenoble University, Saint-Martin-d’Hères in France, led by physicist Alexandre Ponomarenko, presented a study at last month’s meeting of the American Physical Society that seems to hold the promise of a day when what is now lost in translation could be found. Using a gel capsule-like device developed by Cornell University’s Dr. Abraham Stroock, the scientists were able to take a peek inside a simulated tree and observe the cavitations and other activity at the same time sounds were being recording. Cross referencing the visual and audio data, they were able to distinguish the sounds that corresponded with cavitations from other sounds, such as fractures in the wood.

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A record player that plays cross-sections of trees

What are tree rings if not a record? So was the thinking, it seems, behind German artist Bartholomäus Traubeck’s Years installation, which consists of “Modified turntable, computer, vvvv, camera, acrylic glass, veneer, approx. 90x50x50 cm.” Check out the video (also embedded above). Traubeck explains,

A tree’s year rings are analysed for their strength, thickness and rate of growth. This data serves as basis for a generative process that outputs piano music. It is mapped to a scale which is again defined by the overall appearance of the wood (ranging from dark to light and from strong texture to light texture). The foundation for the music is certainly found in the defined ruleset of programming and hardware setup, but the data acquired from every tree interprets this ruleset very differently.

Thanks to Treehugger for the link. I like their conclusion:

Like any great composition, the sounds produced from reading tree-rings are both aesthetically beautiful while at the same time a strangely ethereal glimpse into the otherwise silent life of our planet’s most essential organisms. And likewise, when presented in such a visceral way, it becomes difficult to imagine Earth’s pristine forests as merely places where life can thrive, and not as quiet musicians recording, in their own way, what it means to be alive.

Four days ago, Traubeck uploaded some additional footage: