Trees in fresco needing to be touched up (8)
I believe the answer is:
conifers
'trees' is the definition.
(conifer is a kind of tree)
'in fresco needing to be touched up' is the wordplay.
'in fresco' can be anagrammed to 'CONIFERS'.
Though, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for conifers that I've seen before include "Pines, firs, cypresses" , "Evergreen trees" .)