What is the origin of the Christmas tree and is it accepted in all Christian traditions?
I'm certainly not aware of a "Christmas" tree appearing in the Christmas story, so I'm curious when it was associated with the holiday.
The origin of the Christmas tree is very well documented elsewhere, including Wikipedia.
There are some groups that do not use Christmas trees, for various reasons.
It has it's origins in the reformation.
One German legend claims that Martin Luther was responsible for introducing the use of Christmas trees in the home, in Germany. According to the legend, on his way home one evening, Martin Luther was so overcome by the beauty of a fir tree and stars in the sky, he wanted to tell his family about it. However, upon returning home, words failed him, so he went out and chopped the down and brought it home to share with his family. To mimic the stars that hung over the manger where Christ was born, Martin Luther decorated the tree with candle tapers. This was thought to be the first traditional Christmas tree in Germany.
The History of Christmas Trees
The first documented use of a tree at Christmas and New Year celebrations is argued between the cities of Tallinn in Estonia and Riga in Latvia! Both claim that they had the first trees; Tallinn in 1441 and Riga in 1510. Both trees were put up by the 'Brotherhood of Blackheads' which was an association of local unmarried merchants, ship owners, and foreigners in Livonia (what is now Estonia and Latvia).
Little is known about either tree apart from that they were put in the town square, were dance around by the Brotherhood of Blackheads and were then set on fire. This is like the custom of the Yule Log. The word used for the 'tree' could also mean a mast or pole, tree might have been like a 'Paradise Tree' or a tree-shaped wooden candelabra rather than a 'real' tree.
In the town square of Riga, the capital of Latvia, there is a plaque which is engraved with "The First New Year's Tree in Riga in 1510", in eight languages. You can find out more about the Riga Tree from this website: www.firstchristmastree.com.
A picture from Germany in 1521 which shows a tree being paraded through the streets with a man riding a horse behind it. The man is dressed a bishop, possibly representing St. Nicholas.
In 1584, the historian Balthasar Russow wrote about a tradition, in Riga, of a decorated fir tree in the market square where the young men “went with a flock of maidens and women, first sang and danced there and then set the tree aflame”. There's a record of a small tree in Breman, Germany from 1570. It is described as a tree decorated with "apples, nuts, dates, pretzels and paper flowers". It was displayed in a 'guild-house' (the meeting place for a society of business men in the city). - The History of Christmas Trees.
German tradition tells us that it was Martin Luther who first introduced the Christmas Tree into the home. This is how the story goes:
The first first person to bring a Christmas Tree into a house, in the way we know it today, may have been the 16th century German preacher Martin Luther. A story is told that, one night before Christmas, he was walking through the forest and looked up to see the stars shining through the tree branches. It was so beautiful, that he went home and told his children that it reminded him of Jesus, who left the stars of heaven to come to earth at Christmas. Some people say this is the same tree as the 'Riga' tree, but it isn't! The Riga tree originally took place a few decades earlier. Northern Germany and Latvia are neighbors. - The History of Christmas Trees.
The Christmas Tree tradition is not accepted by all Christians. In fact the Jehovah’s Witnesses do not celebrate Christmas at all.
Some Christian communities do not celebrate Christmas because the actual date of Christ's birth is unknown or because it replaced a pagan holiday.
As covered in Ken Graham's answer, the Christmas tree tradition can be traced back to the Baltic states. However, the trees in, for example, Riga were put up by the "Brotherhood of Blackheads" which was an organisation of foreign Christian merchants. We can assume they were displaying their Christian faith, not paganism. The tree was burned but not till some days after Christmas. It was not "like a Yule log".
Why would they use a tree as a symbol of Christianity? Well the association between Christ and Adam is long standing and scriptural. There is an early reference in the writings of Hippolytus (c 200 AD) referring to Christ as our "new tree of life".
This association lead, I believe, to medieval "mystery" plays performed at Christmas including in their cycle of plays the story of Adam and Eve - an account of creation and the fall, the loss of access to the tree of life - to be followed by the account of the birth of Christ - our Redeemer, our new Tree of life.(e.g the Oberufer cycle of plays)
The staging instructions for one of these plays ("Le Jeu D'Adam") includes the following:
"Let paradise be constructed in a prominently high place [constituatus paradisus loco eminentori]; let curtain and silken hangings be placed around it at such a height that those persons who will be in paradise can be seen from the shoulders upwards; let sweet-smelling flowers and foliage be planted; within let there be various trees, and fruits hanging on them, so that the place may seem as delightful as possible"
The description of the early Christmas trees talk about decorating with fruit and nuts. Early glass baubles were made in the shape of fruits.
I conclude that the custom of erecting a Christmas tree probably originated in its use in mystery plays to represent the Tree of life and hence, metaphorically, Christ himself.