Tree bark is the outer covering of a tree's trunk, branches, and roots. It serves as a protective layer, shielding the tree from pests, diseases, and harsh weather. Bark comes in various textures and colors, depending on the type of tree, such as the smooth birch or the rough oak. Bark is also important for the tree's health. Inside the bark lies the phloem, which transports nutrients and sugars produced by the leaves to the rest of the tree. This process is vital for growth and survival, making bark an essential part of a tree's structure and function in nature.