So, If a tree gets parched in a forest and no one is around to hear it, does it make a sound?
Apparently, the answer is yes. Scientists in France say they've discovered that trees make sounds when they're thirsty or starved for water.
The physicists created a sensitive microphone that they attached to trees and found that the thirstier trees become, the louder the sounds.
Now, in order to hear those sounds with your ear, researchers have to slow them down by a thousand times. What you hear, they say, are gurgling sounds, similar to a straw sucking up that last bit of pop or milkshake.
Trees drink by absorbing water through special tubes in their trunks called xylem. When groundwater dries up, the trees have to pull harder on whatever water is left - which can create air bubbles.
"Every time there was a sound, there were bubbles happening inside the tree. When these bubbles appear, it's bad," said Dr. Alexandre Ponomarenko, the lead scientist on the project.
As NPR reports, two out of three trees are dangerously parched around the world, according to a study in Nature late last year.
"If you increase a little bit of stress, potentially, a lot of trees may die from this drought even," according to Ponomarenko.
As part of their research, Ponomarenko's team at Grenoble University created a "test" tree in a lab.
They put a thin piece of pine wood into a gel capsule filled with liquid, to mimic conditions inside a living tree.
Then, they evaporated the water to simulate a drought. The researchers found that about half of the sounds made by the tree were connected to how they drink.
Researchers hope their discovery will help them know exactly when trees want water, when they "cry out", if you will.
In the future, they believe forest officials could use handheld acoustic monitors to find stressed trees that need emergency watering to prevent permanent damage.
Ponomarenko says there could even be a device that would attach to a tree and constantly listen for sounds. If needed, the device could then trigger an emergency-watering system.
All of this could be especially important, if drought becomes more common around the world because of climate change.