Green areas in deserts (5)
I believe the answer is:
oases
'green areas in deserts' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oases that I've seen before include "These sanctuaries" , "Fertile tracts in a desert" , "Green desert spots" , "Fertile desert places" , "Fertile areas in deserts" .)