Wood's the chap in the car (5)
I believe the answer is:
cedar
'wood's' is the definition.
(cedar is a kind of wood)
'chap in the car' is the wordplay.
'chap' becomes 'Ed' (short for Edward).
'in the' indicates putting letters inside.
'ed' inserted within 'car' is 'CEDAR'.
'the' acts as a link.
(Other definitions for cedar that I've seen before include "Tree giving fragrant wood" , "Cypress-like tree" , "Deodar" , "Fragrant conifer" , "Raced around noble tree" .)