Träd are perennial plants characterized by an elongated stem, or trunk, that supports branches and leaves. They play a crucial role in the ecosystem by producing oxygen through photosynthesis and providing habitats for various species. Common types of trees include ek, gran, and björk. Trees can vary significantly in size, shape, and lifespan. Some, like the sequoiadendron giganteum, can grow to be thousands of years old and reach impressive heights. Trees also contribute to soil health, prevent erosion, and help regulate the climate by absorbing carbon dioxide from the atmosphere.