Thump Thump: Trees Exhibit ‘Heartbeat’

Scientists have discovered that some trees raise and lower their branches several times in the course of the night, indicating a cycle of water and sugar transportation, but they didn’t know why. Plants need water to photosynthesize glucose, the basic building block from which their more complex molecules are formed. For trees, this entails drawing water from the roots to the leaves. Dr. András Zlinszky, at Aarhus University, Denmark, used a laser scanning technique to measure the exact location of branches and leaves of 22 tree and shrub species, and published his observations of substantial unexpected movement cycles. He says, “We detected a previously unknown periodic movement of up to 0.4 inches in cycles of two to six hours. The movement has to be connected to variations in water pressure within the plants, and this effectively means that the tree is pumping. Water transport is not just a steady-state flow, as we previously assumed.” Some might call that pumping action a heartbeat.