Tree not recorded after start of operation (5)
I believe the answer is:
olive
'tree' is the definition.
(I've seen this before)
'not recorded after start of operation' is the wordplay.
'not recorded' becomes 'live' ('live' is the opposite to 'recorded').
'after' means one lot of letters go next to another.
'start of' says to take the initial letters.
The first letter of 'operation' is 'o'.
'live' put after 'o' is 'OLIVE'.
(Other definitions for olive that I've seen before include "Type of green" , "This branch is offered in peace gesture" , "woman" , "One's stoned" , "Oil producer" .)