What's left after burning trees? (5)
I believe the answer is:
ashes
'trees?' is the definition.
(ash is a kind of tree)
'what's left after burning' is the wordplay.
I cannot quite understand how this works, but
'what's left after burning' could be 'ash' (I've seen this before) and 'ash' is located in the answer.
The remaining letters 'es' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ashes that I've seen before include "Cinders - which were once kept in the 3 20 at 18" , "Test cricket series" , "Residue form fires" , "Eng/Aus test series" , "''... to ..., dust to dust'' (burial service)" .)