Cut round opening in pine for sap (7)
I believe the answer is:
deplete
'sap' is the definition.
(thesaurus)
'cut round opening in pine' is the wordplay.
'cut' becomes 'delete' (I can't explain this - if you can you should believe this answer much more).
'round' is an insertion indicator.
'opening in' indicates taking the first letters.
The initial letter of 'pine' is 'p'.
'delete' enclosing 'p' is 'DEPLETE'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for deplete that I've seen before include "Use up a supply" , "Reduce (amount of supplies etc)" , "Reduce (stocks)" , "Reduce the number of" , "Reduce the quantity of (resources)" .)