The Carnegie Museum of Art and Natural History's annual display of five fresh trees this year incorporates iconic Pittsburgh sights, including bridges, mills, steel and rivers, among other things. One of the five trees carries a birthday party theme to celebrate Pittsburgh's 250th anniversary. The display continues through Jan. 8. The museums at 4400 Forbes Ave. in the Oakland section of Pittsburgh will observe the following changes in hours: 10 a.m. to 5 p.m. Dec. 29 and closed Dec. 25 and Jan. 1. Regular hours are 10 a.m. to 5 p.m. Tuesdays through Saturdays, with additional hours until 8 p.m. Thursdays, and noon to 5 p.m. Sundays. Closed major holidays. Admission is $15 for adults, $12 for senior citizens, and $11 for students and children age 3 and older, and free for members and children younger than 3. Call 412-622-3131 or visit the Web site, www.carnegiemuseums.org.