Con-man in twisted tree (8)
I believe the answer is:
cinnamon
'tree' is the definition.
(cinnamon is a kind of tree)
'con-man in twisted' is the wordplay.
'twisted' is an anagram indicator.
'con'+'man'+'in'='conmanin'
'conmanin' with letters rearranged gives 'CINNAMON'.
(Other definitions for cinnamon that I've seen before include "The spice is oddly non-manic" , "Yellow-brown spice from bark of Asian tree" , "Aromatic tree bark used as a spice" , "'Spice in con man, strangely (8)'" , "Yellowish-brown - spice" .)