Are Christmas songs/carols protected by copyright?

Copyright law is a system designed to encourage composers (lyricists, arrangers) to create, and to offer them protection for the work they have created. Copyright protects not only their rights, but also their livelihoods. If you wish to photocopy or reprint the words and/or music of a Christmas song or carol, you'll need to find out if the work is in copyright. If it is, you will need permission from the copyright owner to reprint it or photocopy it.

 The APRA and AMCOS site provides  information  about  music lyrics, arrangements and public domain. They have  also prepared a list of the most popular Christmas carols and songs, explaining who controls the copyright in certain works, and which works are in the public domain (PD) or are traditional (TRAD)

http://www.apra-amcos.com.au/MusicConsumers/FAQCopyrightChristmasSongsCarols.aspx