What can protect wood in burnt arboretum (3)
I believe the answer is:
tar
'what can protect wood' is the definition.
I can't tell whether this definition defines the answer.
'in burnt arboretum' is the wordplay.
'in' says the answer is hidden in the clue.
'TAR' is hidden in the letters of 'burnt arboretum'.
Can you help me to learn more?
(Other definitions for tar that I've seen before include "Old salt or liquid from coal" , "Road-dressing for a sailor?" , "Black substance in cigarettes" , "Black coat" , "Dark flammable liquid" .)