Pretty tree ahead (6,2)

I believe the answer is:

spruce up

I'm a little stuck... Click here to teach me more about this clue!

'pretty tree ahead' is the definition.
I can't tell whether this definition defines the answer.

'tree ahead' is the wordplay.
'tree' becomes 'spruce' (spruce is a kind of tree).
'ahead' becomes 'up' (similar in meaning).
'spruce'+'up'='SPRUCE UP'

Can you help me to learn more?

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

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.