Green material put up around old piece of wood I note (10)
I believe the answer is:
ecological
'green' is the definition.
(I've seen this in another clue)
'material put up around old piece of wood i note' is the wordplay.
I cannot really see how this works, but
'material' could be 'log' (log is a kind of material) and 'log' is present in the answer.
'around' could be 'ca' (circa) and 'ca' is found within the answer.
'old' could be 'o' (abbreviation) and 'o' is located in the answer.
'i' is present in the answer.
'note' could be 'e' (musical note) and 'e' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ecological that I've seen before include "Gaelic cool (anag.)" , "Green" .)