Who cares what it's called O.o As someone who celebrates Christmas I don't care if it's called a Festive Tree; call it a Christmas tree if you care that much to hear it be called one.
It's Tane Mahuta, which translates to Lord of the Forest, and he's named after the god of the forest Tane, who was one of the most heard about / important gods.
Not sure if the tree really was worshipped as such, but it's a pretty big tree.