What you get from burning a tree (3)
I believe the answer is:
ash
I believe this is a double definition.
'what you get from burning' is the first definition.
'a tree' is the second definition.
(ash is a kind of tree)
(Other definitions for ash that I've seen before include "Variety of tree" , "Rowan tree is also called the mountain . . ." , "at village near Whitchurch in Shropshire" , "Hardwood" , "It's used for flooring" .)