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A Cottonwood Tree Makes Sounds, or “Sings”

A Cottonwood Tree Makes Sounds, or “Sings”

The “singing” of cottonwood trees are a function of its natural regulatory processes– a sound emitted when trees try to maintain internal osmotic pressure– and are only one sound from a larger ecosystem. Dr. Bernie Krause conducts research into the sounds of the natural world and has put those online (in GoogleEarth and GoogleMaps form) at Wild Sanctuary. This is another great interview found on

What is most remarkable, which is something discussed in the full version of his talk, “The Great Animal Orchestra,” is that the sounds made by animals fill in niches of sound pitch and timing, just like music; this is a system that Dr. Krause calls the “biophony.” As a hypothetical example, a bird may sing in the upper registers, and at the moment they stop, an insect may instantaneously jump in to communicate in that register until the bird resumes. There is a relationship between the animals in that ecosystem, and it is one that most people don’t think about– at least I didn’t.

The significance– beyond the elaborate timings and impressive coordination on the part of the organisms involved– is that the analysis or visual graphing of sound can show the impacts that people have on the environment in far greater detail than visual examination. Dr. Krause talks about selective logging, and how the loggers can said “Look, the environment looks exactly the same,” (yep, a little heavy-handed on emphasizing the visual) but the auditory data indicates a big hole when comparing the before-logging and after-logging “biophonies.” This work is different in that it regards the scope of sound in an ecosystem as a whole unit, instead of focusing on capturing the sounds of individual animals, as other studies have done.

Here is the singing cottonwood clip:

For the whole program, click on the “Watch Full Program” button in the bottom right corner of the player, or go here.

The image is of Dr. Bernie Krause in the field, taken from the Wild Sanctuary website.