A standard set in reconstruction of larch thicket (9)
I believe the answer is:
chaparral
'thicket' is the definition.
(I've seen this before)
'a standard set in reconstruction of larch' is the wordplay.
'standard' becomes 'par' (standard of play in golf).
'set in' means one lot of letters goes inside another.
'reconstruction of' indicates anagramming the letters (I've seen 'reconstructions of' mean this).
'a'+'par'='apar'
'larch' anagrammed gives 'chral'.
'apar' going within 'chral' is 'CHAPARRAL'.
(Other definitions for chaparral that I've seen before include "US growth area" , "thicket" .)