"Why should I consider investing in a high quality Christmas tree bag?"
The box may work for the first year or two. (be sure to seal it well)
A high quality tree storage system, such as those listed below will provide the following benefits: 1) Maximum structural protection for the tree. Compressing all of the branches to the center pole will protect the branches from getting bent and broken. 2) Easy to manage handles so two people can carry the tree. 3) Some of the bags have wheels for easy movement.