Steers away from horse, making for trees (4)
I believe the answer is:
elms
'for trees' is the definition.
(elm is a kind of tree)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for elms that I've seen before include "Deciduous trees with rough serrated leaves" , "Trees (of late, prone to disease)" , "may have many leaves" , "Trees sound like Cockney steering devices" , "rugged feature of country churchyard" .)