Row about Dr Wood (6)
I believe the answer is:
timber
'wood' is the definition.
(I know that timber is a type of wood)
'row about dr' is the wordplay.
'row' becomes 'tier' (a tier is a row of things).
'about' indicates putting letters inside.
'dr' becomes 'MB' (Bachelor of Medicine).
'tier' going around 'mb' is 'TIMBER'.
(Other definitions for timber that I've seen before include "board" , "Feller's warning cry" , "Deal possibly" , "Trees suitable for building or carpentry" , "Sawn wood" .)