It seems everyday more and more information is being uncovered about trees and the many mysteries within them. We know that they are alive, but it seems they are even more alive than we may have thought. Trees are interconnected underground, we also now know that trees can communicate with one another, but recently scientists have discovered that trees actually have a sort of heartbeat, it is just so slow that they’ve never noticed before.
Up until recently scientists had thought that water moved through trees by the process of osmosis, in a sort of continuous matter, but now they’ve discovered that the trunks and branches of the trees are actually contracting and expanding and essentially pumping water up from the roots to the leaves, kind of like how our heart pumps blood throughout our bodies.
Unlike our bodies and our pulse however, a tree’s is much slower and beats only once every two hours or so and instead of regulating blood pressure it actually regulates the water pressure flowing through the tree.
According to András Zlinszky of Aarhus University in the Netherlands, “We’ve discovered that most trees have regular periodic changes in shape, synchronized across the whole plant, which imply periodic changes in water pressure.”
How Did They Find This Out?
A study conducted in 2017 Zlinsky and his colleague, Anders Barfod, used terrestrial laser scanning to monitor 22 different tree species in an effort to observe the shape of their canopies and how they changed.
All measurements were taken in greenhouses at night in order to rule out the sun and also the wind as factors in the movements in the trees. In several of the trees it was observed that branches moved up and down about a centimeter every couple of hours. After finishing up the night study the researchers came up with a theory about what they believe that movement represents. They believe that the motion is a signal that the trees are pumping water up from their roots and distributing it through their branches.
The researchers believe that this discovery indicates that trees might actually have a type of heartbeat. “In classical plant physiology, most transport processes are explained as constant flows with negligible fluctuation in time,” Zlinszky told New Scientist. “No fluctuations with periods shorter than 24 hours are assumed or explained by current models.”
Unfortunately at this time there is still no explanation as to how the pumping action works. They speculate that perhaps the trunk squeezes the water pushing it up through the xylem, which is a system of tissue in the trunk that transports water and nutrients to all the branches and the leaves.