ACROSS
9. Because lock of hair removed from stronghold. (3) [F _ R] (I think the answer is 'for', but need confirmation of this; fortress minus the tress by any chance?)
12. Duke has foam added, bringing timber. (5,3) [F _ _ _ D _ A _]
DOWN
5. Allow odd grow-man a source of bitter mortification and grief. (8,3,4) [_ O _ _ _ O _ D _ N _ G _ L _]