Treeless plains (7)
I believe the answer is:
steppes
'treeless plains' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for steppes that I've seen before include "Russian treeless plains" , "grassy areas" , "Eurasian grasslands" , "Dry grassy plains of Russia" , "Great plains of Russia" .)