Catalyzes the conversion of (2E,6E)-farnesyl diphosphate (FPP) to yield the bicyclic sesquiterpenol 7-epi-alpha-eudesmol via a 1,10-cyclization, which requires the abstraction of the pyrophosphate from FPP to yield the (E,E)-germacradienyl cation (PubMed:23307484, PubMed:27829890). The only accepted substrate is (2E,6E)-farnesyl diphosphate (FPP) (PubMed:27829890). (2E,6E)-farnesyl diphosphate + H2O = 7-epi-alpha-eudesmol + diphosphate Binds 3 Mg(2+) ions per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. The Asp-Asp-Xaa-Xaa-Asp (DDXXD) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.