This French horn arrangement of O Christmas Tree is in the key of G (concert C). Select the image below for a printable PDF of the melody. The chords for the song are written in the key for French horn. See the main page for O Christmas Tree to read the chords in concert key. The O Christmas Tree Band Play-Along page has more versions of this song, enabling you to play it with other woodwind or brass instruments. The string arrangement of the carol is also in the key of C, so you can play it with violin, viola, cello, or bass. The O Christmas Tree main page features the carol in many different keys, if you are looking for something in a more comfortable range.