Description
In botany, a tree is a perennial plant with an extended stem, or trunk, that supports branches and leaves in most species. In some contexts, the term “tree” may be used to refer only to woody plants with secondary growth, plants that can be used to make lumber, or plants that are taller than a particular height. Trees are a diverse group of plant species that have independently evolved woody trunks and branches to tower over other plants and compete with them for sunlight. Trees are not a taxonomic group. The average lifespan of a tree is hundreds to thousands of years. The larger palm trees, tree ferns, bananas, and bamboo are considered trees by more liberal definitions. Three hundred seventy million years have passed since trees first appeared. Over 3 trillion mature trees are thought to exist on the entire earth. A tree often has numerous secondary branches that the trunk supports above the ground. Typically, this trunk has circulatory tissue to transport materials from one section of the tree to another and woody tissue for strength. For most trees, a layer of bark acts as a barrier of protection around it. The tree is anchored by deep, branched roots that reach considerably beneath the earth’s surface. These roots also draw moisture and nutrients from the soil. The branches split into smaller branches and shoot above ground.
Reviews
There are no reviews yet.