A tree is a tall plant with a woody trunk, branches, and leaves (or needles) that lives for many years. Unlike smaller plants that might last just one season, trees can live for decades, centuries, or even thousands of years, growing stronger and taller as time passes.

Trees start as tiny seeds. An acorn becomes an oak, a pinecone's seed becomes a pine, and a helicopter-shaped seed becomes a maple. The trunk provides structure and carries water from the roots up to the leaves, while the bark protects the tree like armor. Branches spread out to catch sunlight, which trees use to make their own food through a process called photosynthesis.

Different trees have different personalities. Evergreens like pines and firs keep their needles year-round and smell wonderful. Deciduous trees like maples and oaks lose their leaves each fall in a brilliant display of color, then grow them back in spring. Some trees, like willows, droop gracefully, while others, like redwoods, shoot straight up toward the sky.

Trees provide homes for countless creatures (from squirrels to owls to insects), shade on hot days, lumber for building, paper for books, and oxygen for every breath we take. Many trees you see today were planted by people who knew they'd never sit in their shade, giving a gift to future generations.