Oregon Repertory Singers and Youth Choir welcome Union High School’s string orchestra for its “Glory of Christmas” concert from 4 to 5:30 p.m. Dec. 3 at First United Methodist Church, 1838 S.W. Jefferson St., Portland. Additional performances are 4 to 5:30 p.m. Dec. 9 and 10. This season marks Union High School orchestra director Tom Siess’ 40th year of teaching. He is also a long-time member of Oregon Repertory Singers. The choir and orchestra will combine for movements of Vivaldi’s “Gloria” as well as music by Ola Gjeilo, Randall Thompson and a new orchestration of “Written for You” by accompanist Naomi Laviolette. The choir will also sing holiday favorites including Eriks Esenvalds’ “Stars” for choir and tuned wine-glasses and Ethan Sperry’s “Medley of Hannukah Songs.” Tickets range from $25 to $45. Learn more at orsingers.org.