Unpacking the ornaments and the tinsel, untangling the lights, and dusting off the angel are perfunctory tasks that go along with decorating the Christmas tree every holiday season. Adorning the evergreen from top to bottom with wondrous garnishes has become a staple for many during the winter holiday. The history of this tradition spans the millennia.
The importance of the evergreen tree traces back to the Egyptians and Romans.
“The Egyptians were part of a long line of cultures that treasured and worshipped evergreens,” according to Christmas-tree.com. 
1000 years ago, Romans and Christians used branches and even whole trees  to decorate temples and yards for the winter solstice. This idea stemmed from the Egyptians’ earlier culture of treasuring the fir tree as as symbol of eternal life.
Legend has it that St. Boniface, a monk from Devonshire, England, used the Christmas tree to convert pagans. He employed its triangular shape to describe the Holy Trinity of God the Father, Son and Holy Spirit. The converts came to revere the evergreen fir as God’s tree.
During the Middle Ages, people started to bring the trees inside instead of planting them in bowls outside or keeping them planted in the ground. This movement was the platform for the next phase of Christmas tree evolution: embellishment. 

“The first documented use of a tree at Christmas and New Year celebrations is in town square of Riga, the capital of Latvia, in the year 1510,” according to whychristmas.com. 
Martin Luther began the tradition of decorating trees to celebrate Christmas. In the year 1500, while walking in the woods on Christmas Eve, he was struck by the beauty of the evergreens. When he went home, he set up a little fir tree indoors and decorated it with candles in honor of Christ’s birth.
These candles inspired others, notably Germans, to decorate their trees in alternative fashions. Soon, adorning trees with strings of gingerbread, gold covered apples, wafers, and sweets became a common practice in Northern Europe. This beautification inspired glass makers to make small ornaments similar to the decorations used today.
The Baby Jesus was used as the first tree-topper, followed by other variations including angels, shepherds, and stars. Tinsel, among other materials, was added to the growing plethora of tree decorations.
After the tree-decorating ritual traveled around Europe, the Christmas tree arrived in America. Some claim that it was brought by the Hessian troops during the American Revolution, while others say that German immigrants brought the traditions with them in the 1850s.
Over the years, these traditions have been adapted and many families have put their own spin on the tree festivities. Several members of the Convent of the Sacred Heart community have especially unique rituals.
“Every year my mom gets my siblings and me one of those hallmark keepsake ornaments, so we have huge collections. They each have a significant meaning. We put them up together each year,” senior Regina Ferrara said.
Tree-decorating festivities have even been adapted to other celebratory events, like the advent tradition of decorating the Jesse tree. 

The Jesse tree is adorned with ornaments that represent Old Testament figures and events that lead to Jesus’ birth. Every day of advent, a new ornament is added. It helps children and adults alike locate Jesus in the lineage of David, King of Israel and son of Jesse.
“The Jesse Tree records the spiritual ancestors of Jesus. All of them are part of salvation history leading up to the birth of Jesus, our Savior. This ‘tree’ is rooted in Jesse, the father of Kind David,” Mrs. Pregiato, Chair of the Theology Department, said. “Jesus is from the line of David who had received the promise from God that his dynasty would last forever. All of us today are spiritual descendants of Jesus.”
– Isabelle Jeffrey, Staff Writer
Sources:
http://www.whychristmas.com/customs/trees.shtml
http://www.xmyase.com/why-do-we-decorate-a-christmas-tree.php
http://www.christmasarchives.com/trees.html
http://www.christmas-tree.com/where.html
http://www.crossroadsinitiative.com/library_article/811/Jesse_Tree_an_Advent_Tradition.html