I started to do a little internet research and came across the story of monk Crediton Devonshire. In the 7th Century he was traveling around teaching the word of God and would use the fir tree to explain the Holy Trinity: the Father, Son and the Holy Spirit.
The fir tree became an adopted symbol of Christianity and in the 12th Century Europeans would hang the tree from their ceilings. Read more HERE.
Another story suggests that the Ancient Egyptians started the Christmas tree trend when the winter solstice came (around December 20-23), Egyptians would bring palm leaves into their home to symbolize the victory of life over death. Read more HERE.
Some believe the Bible points to the origination of the Christmas tree:
Jeremiah 10:1-5 (King James Version):
There are many more cultures that were speculated to use the "Christmas tree." Regardless, I think it's lost meaning in our current society--seems like people just do things and buy things because it's "tradition."
 Hear ye the word which the Lord speaketh unto you, O house of Israel:
 Thus saith the Lord, Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them.
 For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the axe.
 They deck it with silver and with gold; they fasten it with nails and with hammers, that it move not.
 They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good.