Mistletoe derives its food for survival from trees like the spruce. It serves as a parasitic plant as it cannot survive without taking resources from another plant.
The feeding structures of the mistletoe, which are known as haustoria, grow directly into the vascular system of the tree. In doing so, the mistletoe can pull the nutrients that it needs for growth directly from the sap flow on the tree.
To remove the mistletoe from the spruce tree can be a lengthy process. A knife must be used to remove the mistletoe from the limb. It is also important to use the knife to cut the feeding structures from the vascular system of the tree in order to ensure that it does not grow back.