1. Gravity: The primary force at play is gravity. Fruits and leaves are attached to the branches by a relatively weak connection, called a petiole for leaves and a stalk for fruits. When the tree is shaken, the force of gravity pulls on these structures, overcoming the holding force of the connection.
2. Weakening of the Attachment: The petiole or stalk weakens over time, especially as the fruit ripens or the leaf ages. This weakening makes them more susceptible to detaching when shaken.
3. Wind Resistance: Leaves, especially broad leaves, are designed to catch the wind and move. When a tree is shaken, the wind resistance on the leaves can amplify the shaking force, making them more likely to detach.
4. Mechanical Stress: The shaking itself creates mechanical stress on the branches and leaves, which can weaken the attachments and cause them to break off.
5. Natural Dispersal Mechanism: For some trees, shaking can be a natural dispersal mechanism for their seeds. The wind can carry the seeds further away from the parent tree, increasing the chances of successful germination.
It's important to note: While shaking a tree can cause fruits and leaves to fall, doing so excessively can damage the tree. It's best to avoid shaking trees unless necessary.
