What lianas do in tropical forests, also in the wild fens (7)
I believe the answer is:
festoon
'what lianas do in tropical forests' is the definition.
The definition suggests a singular noun which matches the answer.
'also in the wild fens' is the wordplay.
'also' becomes 'too' (synonyms).
'in' is an insertion indicator.
'the wild' indicates anagramming the letters.
'fens' with letters rearranged gives 'fesn'.
'too' going within 'fesn' is 'FESTOON'.
Can you help me to learn more?
(Other definitions for festoon that I've seen before include "Decorative chain" , "Decorate with strings of flowers or fabric say" , "swag" , "Decorate with hanging ornaments" , "Ornamental garland" .)