Involved in the biosynthesis of cis-abienol, a labdane diterpene that can be used as synthesis precursor of ambergris substitution fragance products. Bifunctional class I/II enzyme in which both the bicyclization and water capture occur in the class II active site, resulting in an intermediary labda-13-en-8-ol diphosphate, which undergoes cleavage of the diphosphate group and final deprotonation at the class I active site. No activity with copalyl diphosphate as substrate. 8-hydroxycopalyl diphosphate = cis-abienol + diphosphate (2E,6E,10E)-geranylgeranyl diphosphate + H2O = 8-hydroxycopalyl diphosphate Binds 3 Mg(2+) ions per subunit. Terpene metabolism; oleoresin biosynthesis. The Asp-Xaa-Asp-Asp (DXDD) motif is important for the catalytic activity in the class II active site relevant for the cyclization of GGPP. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity in the class I active site, presumably through binding to Mg(2+). Belongs to the terpene synthase family. Tpsd subfamily.