Work doubled with an American chopper used for tree (8)
I believe the answer is:
opopanax
'for tree' is the definition.
I know nothing about this answer so I can't judge whether this works.
'work doubled with an american chopper' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'doubled' indicates the doubling of some letters.
'with' means one lot of letters go next to another.
'american chopper' becomes 'ax' (US spelling of 'axe').
'op' duplicated is 'opop'.
'opop'+'an'+'ax'='OPOPANAX'
'used' is the link.
Can you help me to learn more?
(Other definitions for opopanax that I've seen before include "Protective resin" , "Perfume" , "Sticky matter" .)