Nothing smells as wonderful to me as a fresh Fraser fir tree in the living room. Many, or even most, Westerners are currently enjoying the same thing (unless of course, they have fallen to the plastic tree gods). The evergreen tree, decked out in lights and various ornaments is a very old tradition, despite such modernizations as multicolor LED lights. So, how old is this tradition?
The modern Christmas tree is actually derived from a few ancient traditions. However, most common traditions came from Scandinavia. In ancient Scandinavian cultures, people celebrated the winter solstice by decorating evergreen trees with apples. It's pretty cold and snowy in Scandinavian countries, particularly on the shortest day of the year, so seeing a tree that stays pretty and green all year was a ray of hope that the winter would end and spring would come again. Decorations such as fruit (for harvest), nuts (for fertility), and coins (for wealth) decorated both Germanic trees and Celtic druid trees during the winter. The cut wood was then burned (Yule log) as a promise and celebration that the sun would return again.
Eventually, with the spread of Christianity, the church adopted the evergreen tree and other winter greenery to more easily convert Germanic pagans. Though some Christian symbolism has been loosely attached to the modern tannenbaum, it is still a Pagan tradition. In fact, I found many articles arguing whether some Bible verses condemn the idea of decorating a tree in reference to all the ancient celebrations.
As you are aware, there are many different plants that are associated with the winter holidays other than the evergreen tree. I will go through them over the next few days.