Crossing Open Ground takes its title from a book by Barry Lopez, to whom it is dedicated and whose rhapsodic nature writing has prompted comparisons with Henry David Thoreau, bard of Walden. The first thing to know about attending the performance is that you’re welcome to bring your own blanket or a “low outdoor chair.” More to the point, bring comfortable shoes—the sine qua non, per Birgit Nilsson, for singing the role of Isolde, but that’s another story. John Luther Adams—often reflexively described as an “environmentalist” composer, though the label seems reductive—lists this recent creation among his works for orchestra and large ensemble; it’s designed for self-discovery on the part of listeners as well as musicians. From its Aspen premiere in 2023, it migrated—courtesy of the Juilliard School—to Lincoln Center for Earth Month 2024. This April, the LA Philharmonic sponsored a performance by musicians from the USC Thornton School. The scoring is for 40 players (or multiples of 40) on woodwinds, brass, and percussion. Here the count is 40, drawn from the Boston University Tanglewood Institute. (Every iteration so far has had an academic affiliation.) “The piece,” we are advised, “offers an opportunity to rediscover and reconsecrate our sense of place.” All present are free—would it be too bossy to say “encouraged”?—to follow their own individual path through the landscape, physical and musical. “I have traveled a great deal in Concord,” Thoreau once said. Lopez traveled a great deal from pole to pole and all around the Equator. Maybe that’s why the duration of this crossing, per the composer’s works catalogue—can vary from 54 minutes to 81. Latitude indeed. —Matthew Gurewitsch