Involved in the biosynthesis of cis-abienol, a labdane diterpene that can be used as synthesis precursor of ambergris substitution fragance products. 8-hydroxycopalyl diphosphate = cis-abienol + diphosphate Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed specifically in trichomes. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). The expression of both CPS2 and ABS is necessary and sufficient to catalyze the biosynthesis of cis-abienol from geranylgeranyl diphosphate in a heterologous system. Belongs to the terpene synthase family.