Importance of tree
Importance of tree In botany , a tree is a perennial plant with an elongated stem, or trunk , supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth , plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. Trees tend to be long-lived, some reaching several thousand years old. In looser definitions, the taller palms , tree ferns , bananas and bamboos are also trees. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world. A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typically contains woody tissue for