Tree increasing? Get trimmer (6,2)

I believe the answer is:

spruce up

'get trimmer' is the definition.

'tree increasing?' is the wordplay.
'tree' becomes 'spruce' (spruce is a kind of tree**).
'increasing?' becomes 'up'.
'spruce'+'up'='SPRUCE UP'

(Other definitions for spruce up that I've seen before include "Become smart" , "groom" , "Make smarter" , "Titivate" .)

I've seen this clue in The Guardian.

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