Leaves home? (4)
'leaves home?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tree that I've seen before include "Maybe plane" , "Large plant with trunk" , "Large woody plant (4)" , "Diagram representing different relationships" , "Eg, cypress" .)
(Other definitions for tori that I've seen before include "rings" , "doughnuts" , "Large mouldings on columns" .)
(Other definitions for limb that I've seen before include "as part of plane, say" , "Bough" , "Eg, arm, leg" , "Eg wing" , "Wing, perhaps" .)