Hahahaha Kokuma. xD Yes, I remember our teacher (she was the Finnish German teacher too, hehe!) who taught us what all the words meant.
It was really funny, something like:
O'Tannenbaum, O'Tannenbaum (shrill)
*something or other* sind deine Blätte
*something or other* in Sommerzeit
und denn in Winter, und wenn ist schneit.
O'Tannenbaum, O'Tannenbaum
*something or other* deine Blätte
*happy Jiro likes the website* (

)
It's nice to listen to at Christmas, hehe.