Timber suppliers (5)
I believe the answer is:
trees
'timber suppliers' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for trees that I've seen before include "Ashes, perhaps?" , "Woods" , "Steer into the plants" , "Elms, pines etc" , "Elders perhaps" .)