Yes, deer can eat Christmas trees. While Christmas trees are typically not a part of a deer's natural diet, they can be a tempting snack for deer when the trees are readily available. Deer have strong jaws and sharp teeth that allow them to easily bite into and chew through the branches and needles of a Christmas tree. However, eating too much of the tree can cause digestive problems and lead to stomach aches. It is important to keep Christmas trees out of reach of deer to prevent them from eating them and risking injury.