Tree of longer standing (5)

I believe the answer is:

elder

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'tree' is the definition.
(elder is a kind of tree)

I can't explain the remainder of the clue.

(Other definitions for elder that I've seen before include "Senior leader" , "Wise guy" , "Bush" , "more mature" , "Kind of tree or sage person" .)

I've seen this clue in the Sydney Morning Herald.

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