Whilst listening to the headphones hanging from the tree’s branches you will hear two sounds:
- A deep rumbling sound that is produced by the tree moving.
- And in the background you will hear a quiet popping sound that is produced by the water passing through the xylem tubes and mixing with air on its way up to the leaves.
In Order to get the water up to the leaves a high pressure is generated and it is when the water and air mix under pressure that we can hear it.
This water movement is what keeps the tree alive by providing the leaves with the necessary water to keep the tree cool and to turn into sugar (sap).
An average sized oak tree will drink around 200 litres of water on a warm, sunny day.