Which Christmas special, directed by Bill Melendez, featured an aluminum Christmas tree?
Aluminum Christmas tree:  The aluminum Christmas tree was used as symbol of the commercialization of Christmas in the highly acclaimed and successful 1965 television special, "A Charlie Brown Christmas", which discredited its suitability as holiday decoration. A Charlie Brown Christmas:  Produced by Lee Mendelson and directed by Bill Melendez, the program made its debut on CBS on December 9, 1965.
A Charlie Brown Christmas