Sweet tree may fall thus (7)
I believe the answer is:
gumdrop
'sweet' is the definition.
(gumdrop is a kind of sweet)
'tree may fall thus' is the wordplay.
I cannot really understand how this works, but
'tree' could be 'gum' (gum is a kind of tree) and 'gum' is found in the answer.
'fall' could be 'drop' (synonyms) and 'drop' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for gumdrop that I've seen before include "chew" , "It may be sucked" , "Fungus attacking wood" , "Gelatinous type of sweet" , "Jelly-like sweet" .)