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How do tree branches form? © Getty Images

How do tree branches form?

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Trees can branch out with a little help from buds, the growth hormone auxin, and their apical meristem...

Asked by: James Slatter, Feltwell


As tree trunks grow upwards, buds are produced on either side. These buds are initially dormant because the growing tip at the top, called the ‘apical meristem’, produces the hormone auxin, which inhibits their development. Once the apical meristem has grown far enough away, the concentration of auxin near the bud drops and it can begin growing sideways. This sideways shoot also lays down its own buds, which are in turn kept dormant until the shoot’s own growing tip has advanced enough.


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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.


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