Leave tree on way to start (2,5)

'start' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'leave tree on way' is the wordplay.
I cannot quite understand how this works, but
'leave' could be 'go' (to go is to depart or leave) and 'go' is located in the answer.
'tree' could be 'fir' (fir tree is a kind of tree) and 'fir' is found within the answer.
'way' could be 'st' (abbreviation for street) and 'st' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).

'to' is the link.

Can you help me to learn more?