Sheep found under tree in Hindu retreat (6)
I believe the answer is:
ashram
'hindu retreat' is the definition.
(type of South Asian religious retreat)
'sheep found under tree' is the wordplay.
'sheep' becomes 'ram' (male sheep).
'found under' is a charade indicator (letters next to each other).
'tree' becomes 'ash' (ash is a kind of tree).
'ram' put after 'ash' is 'ASHRAM'.
'in' is the link.
(Other definitions for ashram that I've seen before include "Retreat -- a marsh (anag)" , "Hindu hermitage" , "religious community" , "Guru's community" , "Place of religious retreat for Hindus" .)