Science Focus - the home of BBC Science Focus Magazine
Why do trees lose their leaves? © iStock

Why do trees lose their leaves?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Whatever the weather, whether it’s good or bad, you’ll need that rake to clear them up.

Asked by: Barry Cull, by email

Advertisement

Deciduous trees shed their leaves as an active process that evolved to conserve resources and protect the tree from being blown over in the windier winter months. The process is controlled by the plant hormone auxin.

As light levels and temperatures drop, the flow of auxin to the leaves slows and levels of another hormone, ethene, rise. This signals the cells at the base of the leaf to weaken their cell walls, at the same time as other cells expand to break the connections between the weakened cells. The result is like tearing perforated paper, and the leaf drops to the ground.

Read more:


Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.

Authors

luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

Advertisement
Advertisement
Advertisement

Sponsored content