Tree
A perennial plant with an elongated stem, or trunk, usually supporting branches and leaves.
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A tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In botany, definitions vary; broader definitions include taller palms, tree ferns, bananas, and bamboos, while narrower definitions require a woody trunk formed by secondary growth. Trees are not a monophyletic group but have independently evolved a trunk and branches to compete for sunlight.
Most tree species are angiosperms (hardwoods); many others are gymnosperms (softwoods). Trees tend to be long-lived, some reaching several thousand years old. The earliest trees evolved around 400 million years ago, and it is estimated that there are around three trillion mature trees in the world currently.
Lore & Background
Trees pull carbon dioxide from the air and lock carbon in their wood. Forests shelter countless animals and plants, with tropical rainforests being some of the most species-rich places on Earth.
People rely on trees for shade, building materials, fuel, and fruit. Across the globe, forests are shrinking as land is cleared for farming. Because they live so long and provide so much, trees have long been honored, with sacred groves appearing in many cultures and playing a part in numerous mythologies.
Reader's Guide
Trees usually reproduce using seeds. Flowering plants have their seeds inside fruits, while conifers carry their seeds in cones, and tree ferns produce spores instead. A tree typically has many secondary branches supported clear of the ground by the trunk, which contains woody tissue for strength and vascular tissue to carry materials.
The trunk is surrounded by bark. Below ground, roots anchor the tree and extract moisture and nutrients. Above ground, branches divide into smaller branches and shoots bearing leaves, which capture light energy for photosynthesis.
Trees are either evergreen or deciduous. The crown is the spreading top of a tree; the uppermost layer in a forest is the canopy. A sapling is a young tree.
Frequently Asked Questions
What is a Tree?
A tree is a long-lived perennial plant defined by a single, elongated woody trunk that typically holds up a canopy of branches and leaves. It persists year after year, growing taller and thicker rather than completing its life cycle in a single season.
Are all trees the same species?
No — 'tree' is not a single taxonomic category at all. It is an ecological body-form that many unrelated plant lineages have independently evolved, each arriving at a trunk-and-branch structure to outcompete neighbors for sunlight.
What distinguishes a tree from a shrub?
The defining feature is one dominant, upright woody trunk that elevates the leafy crown well above the ground. Shrubs, by contrast, are usually multi-stemmed and shorter, lacking that single central column.
Where do most of the world's trees grow?
Roughly 43% of all tree species are found in tropical regions. The remaining diversity is scattered across subtropical, temperate, and even some cold-climate zones.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Tree (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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