Environment

Arboreal ‘Heartbeat’

Dutch researchers say they have found evidence of a kind of “heartbeat” in trees that causes them to change shape in a regular rhythm that is much shorter than a day-night cycle.

András Zlinszky and colleague Anders Barfod at Aarhus University scanned 21 species of trees in windless and lightless conditions and found seesaw oscillations in branches that were most pronounced in magnolia trees.

Branches move up and down an average of 0.6 inch during cycles that are 2 to 6 hours in duration.

The pair thinks the pulses are evidence that trees have a “heartbeat” in which they actively squeeze water upward from their roots.