Sesquiterpene synthase that catalyzes the formation of sesquiterpenes and sesquiterpenoid alcohols (PubMed:27231873). Converts farnesyl diphosphate (FPP) to 10-epi-juneol (PubMed:27231873). Converts FPP to tau-cadinol (PubMed:27231873). 10-epi-juneol is the major product (PubMed:27231873). (2E,6E)-farnesyl diphosphate + H2O = 10-epi-juneol + diphosphate (2E,6E)-farnesyl diphosphate + H2O = diphosphate + tau-cadinol Binds 3 Mg(2+) ions per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. Highly expressed in leaves (PubMed:27231873). Expressed in roots and flowers (PubMed:27231873). The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.