Tree tapped for sap (5)
I believe the answer is:
'tree tapped for sap' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for maple that I've seen before include "Ample sort of tree" , "Tree of Acer genus" , "Tree of the sycamore family" , "Tree; sugar from it" , "----- leaf: symbol of Canada" .)