It's turning out nice for a tree (7)
I believe the answer is:
conifer
'a tree' is the definition.
(I know that conifer is a type of gymnospermous tree)
'it's turning out nice for' is the wordplay.
'it's turning out' indicates anagramming the letters.
'nice'+'for'='nicefor'
'nicefor' is an anagram of 'CONIFER'.
(Other definitions for conifer that I've seen before include "Fir or larch, for example" , "one branching out" , "The tree keeps its leaves" , "Evergreen (generally)" , "Tree such as pine, yew etc" .)