Protective garment needed by chap in a forest (8)
I believe the answer is:
pinafore
'protective garment' is the definition.
(I've seen this before)
'needed by chap in a forest' is the wordplay.
'needed by' indicates a hidden word (the solution letters are needed to write the clue).
'PINAFORE' is hidden in the letters of 'chap in a forest'.
(Other definitions for pinafore that I've seen before include "Protective garment worn over front" , "Musical craft" , "gives homely protection" , "Sort of apron" , "Apron-like garment" .)