Ape eats second and third banana on top of the forest (6)
I believe the answer is:
canopy
'top of the forest' is the definition.
(upper branches of a forest)
'ape eats second and third banana' is the wordplay.
'ape' becomes 'copy' (synonyms).
'eats' means one lot of letters goes inside another.
'second and' becomes 'a' (I can't justify this - if you can you should believe this answer much more).
'third banana' becomes 'n' (3rd letter of 'banana').
'a'+'n'='an'
'copy' placed around 'an' is 'CANOPY'.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for canopy that I've seen before include "Cover above four-poster" , "Overhead covering, on bed or throne say" , "in the topmost branches" , "Uppermost branches of forest trees" , "Ornamental covering" .)