Tree

Tree

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. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight.

Characteristics

Trees tend to be long-lived, some reaching several thousand years old. The world's oldest known tree, a bristlecone pine tree, is estimated to be over 5,000 years old. Trees have been in existence for 370 million years. They are a crucial part of the Earth's ecosystem due to their role in photosynthesis, the process by which light energy is converted into chemical energy.

Classification

Trees are usually classified based on their leaf type. There are two main types of trees: deciduous and evergreen. Deciduous trees lose their leaves in the autumn and grow new ones in the spring. Evergreen trees, on the other hand, retain their leaves year-round.

Importance

Trees play a significant role in reducing erosion and moderating the climate by removing carbon dioxide from the atmosphere and storing large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of animals and plants. They also provide shade, wood for building and fuel, food, and medicine.

See also

• Forest
• Wood
• Lumber
• Photosynthesis
• Carbon dioxide