That's a great question! Christmas trees are usually evergreen, meaning they retain their leaves throughout the year. Most commonly, Christmas trees are either fir or spruce trees, which have a rich green color and strong branches that are perfect for hanging ornaments and lights. However, there are also some types of evergreen trees that can make great Christmas trees, like cedar and pine trees. These trees also have a wonderful Christmas scent that can add to the atmosphere of the holiday season.