In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species.
In botany, trunk refers to the main wooden axis of a tree, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the trunk to the top, depending on the species.
Botany, also called plant science, plant biology or phytology, is the science of plant life and a branch of biology.
Plants, also called green plants, are multicellular eukaryotes of the kingdom Plantae.
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 botany, secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate, and gives rise to primary tissue.
Wood is a porous and fibrous structural tissue found in the stems and roots of trees, and other woody plants.
Lumber is wood that has been processed into beams and planks, a stage in the process of wood production.
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.
In looser senses, the taller palms, the tree ferns, bananas and bamboos are also trees.
A fern is a member of a group of about 10,560 known extant species of vascular plants that reproduce via spores and have neither seeds nor flowers.
The banana is an edible fruit, botanically a berry, produced by several kinds of large herbaceous flowering plants in the genus Musa.
The Arecaceae are a botanical family of perennial climbers, shrubs, acaules and trees commonly known as palm trees.
Trees tend to be long-lived, some reaching several thousand years old.
The tallest known tree, a coast redwood named Hyperion, stands 115.6 m high.
Hyperion is the name of a coast redwood in Northern California that was measured at 115.61 m, which ranks it as the world's tallest known living tree.
Sequoia sempervirens is the sole living species of the genus Sequoia in the cypress family Cupressaceae.
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 strength, and vascular tissue to carry materials from one part of the tree to another.
Vascular plants, also known as tracheophytes and also higher plants, form a large group of plants that are defined as those land plants that have lignified tissues for conducting water and minerals throughout the plant.
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants.
Xylem is one of the two types of transport tissue in vascular plants, phloem being the other.
For most trees it is surrounded by a layer of bark which serves as a protective barrier.
Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil.
Above ground, the branches divide into smaller branches and shoots.
The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development.
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities.
Flowers and fruit may also be present, but some trees, such as conifers, instead have pollen cones and seed cones; others, such as tree ferns, produce spores instead.
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 12 extant division-level taxa within the Kingdom Plantae and 10 within the extant land plants.
In biology, a spore is a unit of asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavorable conditions.
Tea is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the Camellia sinensis, an evergreen shrub native to Asia.
Trees play a significant role in reducing erosion and moderating the climate.
Climate is the statistics of weather, usually over a 30-year interval.
They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues.
The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity.
Carbon dioxide is a colorless and odorless gas vital to life on Earth.
Carbon is a chemical element with symbol C and atomic number 6.
Trees and forests provide a habitat for many species of animals and plants.
Tropical rainforests are one of the most biodiverse habitats in the world.
Tropical rainforests occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation value of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest.
Biodiversity, a contraction of "biological diversity," generally refers to the variety and variability of life on Earth.
Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses.