How Does a Tree Know When to Lose Its Leaves?

Imagine a tree is like a sleepy kid who knows when it's time to go to bed. Inside the tree, there’s a special kind of message called phytochrome that helps it know if it's day or night, and whether it's summer or winter. When the days get shorter and the light changes, this message tells the leaves it's time to say goodbye and fall off. It's like the tree is listening for the sound of a clock ticking in the sky.

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Examples

A tree loses its leaves when the light changes, just like a person knows it's time for bed when it gets dark.
When the days get shorter, a tree starts preparing to let go of its leaves, kind of like how you start packing your suitcase before a trip.
Leaves fall off when they receive more far-red light, which is why trees in the forest lose their leaves later than those on the edge.

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Categories: Environment · trees,seasons,botany