"Trees that remain green in the winter have been symbolic of life in the midst of death, and of rebirth, in many cultures. The Christian folk-religious custom of erecting and adorning evergreen trees in the middle of winter was borrowed directly from existing practice, regardless of whether the custom had pagan roots. Some of the existing meaning has been carried over into Christian culture, together with these practices.
"Trees appear with symbolic meaning throughout the Bible: and the Christmas tree alludes to and builds upon this biblical symbolism. From the symbolic tree of knowledge of good and evil, concerning which the Fall of man and the curse of death came, to the tree of life from access to which mankind has been cut off, to the Oak of Mamre which "witnessed" the covenant made with Abraham and the renewal of that covenant with Joshua, to promises concerning the root of Jesse, the Branch, the Messiah, who was hung on a tree to bear the curse, and has been raised up again as a tree of life for the healing of the nations: the Christian story can be told from beginning to end in the symbolic terms of trees.
"To focus on one stream of the development of this late Christian symbol, the Christmas tree symbolizes, in part, the promised "Branch", the Messiah, who must be the "Root of Jesse", the descendant prefigured by Jesse's royal son, David. The tree symbolizes the human geneaology of Jesus and especially his tie to David's royal line through Solomon, which had been perplexingly cut off by God from ever inheriting the throne, after Jeconiah. This connection to the cut-off line is symbolized by the cut-down tree, and is indirectly a symbol of the Son of God. According to Christian tradition, although a descendant of Nathan on his mother's side, Jesus is an heir of Solomon on his supposed father's side. In other words, if Joseph were in fact Jesus's father, then Jesus cannot be the Messiah, because Joseph is descended from Jeconiah, the cut-off line.
"But through his mother, the genealogy of Jesus satisfies the promise of the Messiah in terms of human descent, and this is symbolized by the erect tree. It is an evergreen, because of his eternal origin as God, according to Christian belief. And yet, the tree is also customarily cut down before it is decorated, symbolizing that Jesus is also an heir of the line of Solomon by adoption, through Joseph. So, Christians think that God's word was miraculously fulfilled through the virgin birth, because in that way, the Branch came from the cut-off line of Jesse by adoption, and also by the living line of Jesse. By the birth of Jesus, the promise concerning Jesse's line has been fulfilled, Christians believe, and in this restoration Adam and Eve's line, all mankind, redeemed from futility and death, is symbolized. And that is why the Christmas tree is cut down, but restored erect, evergreen and clothed in light, in symbolic commemoration of the virgin birth."*
*adapted from wikipedia.com
