There are several types of trees that can be used as a Christmas tree. The most common and traditional choice is the Norway Spruce, which has dark green needles and a classic Christmas tree shape. Other popular choices include the Douglas Fir, the White Fir, and the Balsam Fir. These trees all have a natural cone shape and soft needles, making them ideal for decorating and displaying ornaments. For a more unique look, some people opt for artificial trees made from PVC or other materials.