A tree is composed of many parts, each with its own unique characteristics. The TRUNK is the main stem of the tree and is typically the thickest part. The ROOT is the part of the tree that is underground and helps to anchor the tree in the ground. ROOTS also absorb water and nutrients from the soil. Leaves are the green, flat parts of the tree that produce food for the tree through photosynthesis. Limbs are the branches of the tree that extend out from the TRUNK. BARK is the protective outer layer of the tree that helps protect it from disease and pests. Boughs are large branches that extend out from the TRUNK. Branches are smaller limbs that extend out from the boughs. Finally, the BOLE is the main stem of the tree, just below the branches.