I don't know much about the history of Christmas traditions. Whatever its origin, I'm struck by the paradoxical and strange nature of the Christmas tree. In the depths of winter we bring a green tree into our house and place it at the centre of our celebrations, and the locus of the abundance of the season in the form of our gift giving. Because of the tree Christmas is always united in my mind with green, with verdant beautiful forest green, despite its temporal home in the depths of winter.
The bringing of green things into the home reminds me of the Jewish holiday of Shavuot, during which it is traditional to decorate the inside of the home with green plants. This associative connection between the two holidays leads me to contemplate the commonality between the two: both celebrate revelation. Shavuot celebrates the giving of the Torah on Mt Sinai. Christmas celebrates the incarnation of the Torah as a person- Jesus Christ. In both cases the revelation of God's face is associated with green things- the pure force of life, or as Dylan Thomas put it "the force that through the green fuse drives the flower".
The tree in Christmas also celebrates life in the depth of the sleeping death of winter and is an obvious symbol for the resurrection and more broadly redemption in Christ. To my mind green things speak of the life and wisdom of the Father, and of the creation of all things in and through Christ. The evergreen at the heart of our homes speaks of the robust indestructibility of the love of the Father and the Son, its green branches and the tang of pine quickening our senses amidst the quiet, desolate stillness of winter. Life fertile and eternal pulses there.