Tan Dun conducts two Tan Dun world premieres. As we go to press, one is still unnamed. The second is listed as Requiem for Nature, a title almost too close to the bone to contemplate. The piece features a prominent solo part for Jörgen van Rijen, trombone. Familiar to New Yorkers as the artistic director of the Park Avenue Armory, the trailblazing French Lebanese theater artist Pierre Audi is preparing a so-called mise-en-espace, so expect something unusual to look at. —M.G.