The ritualistic donning of the evergreen Christmas tree is seeped deep in the tradition of man, and has nothing to do with religion.
The evergreen tree has played a role in Winter celebrations since ancient times, as a symbol of fertility and reproduction. Evergreens were set up in the home as symbolic idols, adorned with apples and other fruit. Decorations were intended as fruit offerings, and it is speculated that is where the idea of putting gifts under the tree originated.
Many pagan festivals used evergreen trees to honor gods and spirits. Nords used trees as a symbol that Winter would pass and the green of Spring would return. The Druids of ancient England and France decorated oak trees with fruit and candles in honor of their gods at harvest time. Romans would decorate their trees with trinkets, candles and small pieces of metal for Saturnalia ceremonies.
The modern custom of the Christmas tree is said to originate in Germany. German would bring trees in their homes to decorate. In areas where evergreen trees were scarce, families would build a Christmas pyramid out of wood and adorn it with branches and chandles.
It’s unknown the exact date that trees were first decorated in America, but the term “Christmas Tree” did not come into common use until 1830 when it spread throughout the land with the arrival of German immigrants. One of the first public displays of the Christmas Tree was set up by German settlers in Pennsylvania at a time when most considered the tree to be a pagan symbol. They would bake fancy ornaments for their trees, and eat them once the tree was taken down.
German glassblowers began producing lightweight glass balls to replace the heavier, natural decorations which weighed down the tree limbs. The trimmings were said to represent the joy and light of Christmas, with a star on top to represent the “Star of the East.”
English royalty made the Christmas tree popular with the first tree at Windsor Castle in 1841. Prince Albert, husband of Queen Victoria, adorned the first English Christmas tree with candles, candies, fruits and gingerbread. Soon the custom spread throughout England.
The tree is said to have gained its Christian symbolism by St. Boniface and later, by Martin Luther.
Source: Christmas Tree (Wikipedia) & Nova Reinna