Shout when trunks fall down! (6)
I believe the answer is:
timber
'down' is the definition.
The definition and answer can be both natural objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for timber that I've seen before include "Wood prepared for use in carpentry or building" , "Deal possibly" , "Ash perhaps" , "Trees suitable for building or carpentry" , "Feller's warning cry" .)