Tree on mountain, for example, remains (3)
I believe the answer is:
ash
This clue might be a double definition.
'tree on mountain' is the first definition.
'ash' can be an answer for 'tree' (ash is a kind of tree). I am not certain of the 'on mountain' bit.
'remains' is the second definition.
(remains of a fire)
'for example' acts as a link.
Can you help me to learn more?
(Other definitions for ash that I've seen before include "End of fire" , "Knotty - - (Ken Dodd)" , "Silvery grey" , "One [TYPE OF TREE]" , "Result of burning - deciduous tree" .)