Tree exudation (5)
I believe the answer is:
resin
'tree exudation' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for resin that I've seen before include "hashish, say" , "Rinse out this substance from trees" , "Tree gum" , "Unprocessed pine secretion" , "Lac" .)