Scientists have discovered that trees may have a heartbeat. However, it is extremely slow, which is why we haven’t been able to notice it until now.
The study found that trunks and branches contract and expand to pump water throughout the tree’s body so that it can reach the roots and the leaves. It is a mechanism quite similar to what we know as the cardiovascular system.
However, while the cardiovascular system found in animals and humans is actively working, trees only do it every two hours, approximately. The study also revealed that a tree’s “heartbeat” also reduces water pressure within its body.
The study was published in 2017 by scientists Zlinszky and Anders Barford. The partners utilized terrestrial laser scanning to observe 22 different species of trees and see whether their shapes fluctuated within a given period.
These measurements were conducted at night to discard environmental factors like the wind or the sun as the potential causes.
Many of the trees ended up “moving” their branches up and down by at least one centimeter every two hours.
Then, the scientist theorized that the movement could be that the trees are actually “pumping” water from their roots. Essentially, it would work almost exactly as the cardiovascular system.
As of now, it’s unknown how the “pumping” mechanism actually works. The researchers say that it could be due to the trunk “squeezing” the water and pushing it upward through the xylem, a tissue system that transports water and nutrients throughout the tree’s body.
The study was published via Plant Signaling and Behavior.
Likewise, Zlinszky and his co-authors published another research paper that proved that birch trees sleep during the night.
The study suggests that birch trees “drop” their branches before dawn because the internal water pressure of the tree has changed. Since there’s not enough sunlight during the night to activate photosynthesis, trees may “relax” their branches to save energy.
Plus, the research says that the birch movements follow the day-night cycle.
However, there are key differences between both studies. The “pumping” movement happens with more frequency than the “dropping” of the branches. Still, both discoveries are extremely exciting and could suggest that we still have many things to understand about trees and their behavior.
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