Involved in the biosynthesis of (+)-O-methylkolavelool. Catalyzes the conversion of geranylgeranyl diphosphate into (+)-kolavenyl diphosphate. (2E,6E,10E)-geranylgeranyl diphosphate = (+)-kolavenyl diphosphate The Asp-Xaa-Asp-Asp (DXDD) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.