Fruit tree posed problem in need of answer (7)
I believe the answer is:
satsuma
'fruit tree' is the definition.
(satsuma is a kind of fruit tree)
'posed problem in need of answer' is the wordplay.
'posed' becomes 'sat' (posed or sat for an artist).
'problem' becomes 'sum' (as in a mathematical problem).
'in need of' says to put letters next to each other.
'answer' becomes 'a' (abbreviation eg in Q and A).
'sat'+'sum'+'a'='SATSUMA'
(Other definitions for satsuma that I've seen before include "A small citrus fruit" , "Small, easily-peeled orange" , "Type of small orange" , "Segmented item" , "sort of orange" .)