Converts farnesyl diphosphate to the bicyclic olefins alpha-copaene, (E)-beta-caryophyllene, and to the macrocyclic sesquiterpene germacrene D (PubMed:21607717). Mediates also the biosynthesis of minor sesquiterpene hydrocarbons including delta-cadinene (PubMed:21607717). Involved in indirect defense by producing volatile signals attracting natural enemies of herbivores (PubMed:21607717). (2E,6E)-farnesyl diphosphate = alpha-copaene + diphosphate (2E,6E)-farnesyl diphosphate = (+)-germacrene D + diphosphate (2E,6E)-farnesyl diphosphate = (-)-(E)-beta-caryophyllene + diphosphate (2E,6E)-farnesyl diphosphate = delta-cadinene + diphosphate Secondary metabolite biosynthesis; terpenoid biosynthesis. Monomer. 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.