In botany, a tree is a perennial woody plant with a single main trunk taller than about 2 metres, with xylem tissue in the trunk and branches that continues to enlarge during the life of the plant by the process of secondary growth.
In common usage, the definition of tree may be narrower, including only very tall plants or those that could yield significant wood. The definition can instead be broader, including tall plants without secondary growth such as the taller palms and the tree ferns. Bamboo is a tall woody plant that is not usually considered to be a tree.
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. 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 chemical energy by photosynthesis, providing the food needed by the tree for its growth and development.
Flowers and fruit may also be present, but some trees such as conifers instead have pollen cones and seed cones, and others such as tree ferns produce spores instead.
Trees tend to be long-lived, some reaching several thousand years old. The tallest known specimen on Earth is 115.6 m (379 ft) and they have a theoretical maximum height of 130m (426 ft). Trees have been in existence on the Earth for 370 million years. Trees are not a taxonomic group but are a number of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants and make full use of the sunlight.
Trees play a significant part in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. 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. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered and they play a role in many of the world's mythologies.
Other articles related to "tree":
... Chief among the scenic attractions is the Lone Cypress Tree (36°34′07″N 121°57′55″W / 36.568738°N 121.965321°W / 36.568738 -121.965321 (Lone ... Smith, said "The image of the tree has been trademarked by us," and that it intended to control any display of the cypress for commercial purposes ... that "they cannot even use existing pictures of the tree for commercial purposes." Other legal commentators have questioned the Pebble Beach Company's ability to invoke intellectual property laws to ...
... When Auckland was founded as a colonial town a tree stood near the summit which gave the hill its English name ... This tree was cut down by a white settler in 1852, in an act of vandalism in one account, or for firewood in another ... It seems likely this was a different tree from the totara (Podocarpus totara) which, as a sacred tree, had given the hill one of its Maori names ...
... The Paramount Hay Tree is a California State Historical Landmark ... It is a still standing mature camphor tree remembered for its importance to the hay trading marketplace of the towns of Hynes and Clearwater, which later incorporated as Paramount ... The hay traders met under the tree each working day to discuss the price of hay ...
... It is cited as a timber tree, and also it is used as a urban tree ... The tree is also used as an ornamental tree in landscaping ... Extracts from the tree, known as "ipê-preto", are used locally as medicine for cancer and skin-diseases ...
... Usage of the name may (or may not) include the tree that yields this wood ... Diesel Tree, Kerosene Tree, Kupa'y, Cabismo, or Copaúva Diospyros blancoi, Mabolo, Velvet Apple, or Kamagong native to the Philippines Erythrophleum ... Red ironwood Lyonothamnus floribundus, Lyon tree Mesua ferrea, Rose chestnut or Ceylon ironwood or Nahar Nestegis apetala, Coastal maire, Broad-leaved maire or Ironwood ...
Famous quotes containing the word tree:
“The tree which moves some to tears of joy is in the eyes of others only a green thing that stands in the way. Some see nature all ridicule and deformity ... and some scarce see nature at all. But to the eyes of the man of imagination, nature is imagination itself.”
—William Blake (17571827)
“the scythers, Time and Death,
Helmed locusts, move upon the tree of breath;”
—Robert Lowell (19171977)
“As a tree my sin stands
To darken all lands;
Death is the fruit it bore.”
—Christina Georgina Rossetti (18301894)