A tree trunk is the thick, central part of a tree that supports its branches and leaves. It is made up of several layers, including the bark, which protects the tree, and the wood, which provides strength. The trunk helps transport water and nutrients from the roots to the rest of the tree, allowing it to grow tall and healthy. The size and shape of a tree trunk can vary greatly depending on the type of tree, such as an oak or a pine. A strong trunk is essential for the tree's stability, especially during storms or high winds, helping it withstand nature's challenges.