Portal:Trees
The Trees Portal
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. 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 monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are around three trillion mature trees in the world.
A tree typically has many secondary branches supported clear of the ground by the trunk, which 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 sugars by photosynthesis, providing the food for the tree's growth and development.
Trees usually reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms, bananas, and bamboos also produce seeds, but tree ferns produce spores instead.
Trees play a significant role 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 among 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 much 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, with sacred groves in various cultures, and they play a role in many of the world's mythologies. (Full article...)
Ficus obliqua, commonly known as the small-leaved fig, is a tree in the family Moraceae, native to eastern Australia, New Guinea, eastern Indonesia to Sulawesi and islands in the southwestern Pacific Ocean. Previously known for many years as Ficus eugenioides, it is a banyan of the genus Ficus, which contains around 750 species worldwide in warm climates, including the edible fig (Ficus carica). Beginning life as a seedling, which grows on other plants (epiphyte) or on rocks (lithophyte), F. obliqua can grow to 60 m (200 ft) high and nearly as wide with a pale grey buttressed trunk, and glossy green leaves.
The small round yellow fruit ripen and turn red at any time of year, although ripening peaks in autumn and winter (April to July). Known as a syconium, the fruit is an inverted inflorescence with the flowers lining an internal cavity. Ficus obliqua is pollinated by two species of fig wasp—Pleistodontes greenwoodi and P. xanthocephalus. Many species of bird, including pigeons, parrots and various passerines, eat the fruit. The range is along the east coast from Queensland, through New South Wales in rainforest, savanna woodland, sclerophyll forest and gallery forest. It is used as a shade tree in parks and public spaces, and is well-suited for use as an indoor plant or in bonsai. All parts of the tree have been used in traditional medicine in Fiji. (Full article...)Did you know? -
- ... that President Bill Clinton said he would personally pay the bill to keep the National Christmas Tree (pictured) lit during the government shutdown resulting from disagreements on the 1996 federal budget?
- ... that global precedence is the tendency to see the forest, and not the trees?
- ... that the mistletoe species Amyema congener of eastern Australia can grow on non-native peach, plum and pear trees?
- ... that foliage from the Australian rainforest tree Grevillea baileyana was used in the floral arrangements handed to medal winners at the 2000 Summer Olympics in Sydney?
- ... that most of the habitat of the vulnerable tree Eucalyptus benthamii has disappeared under Warragamba Dam or been cleared?
- ... that the inspiration for the Paustian House in Copenhagen came to architect Jørn Utzon while he was walking through a forest of beech trees?
- ... that Washington was the second largest tree of its kind until its collapse in 2005?
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Adansonia is a genus made up of eight species of medium-to-large deciduous trees known as baobabs (/ˈbaʊbæb/ or /ˈbeɪoʊbæb/) or adansonias. They are placed in the Malvaceae family, subfamily Bombacoideae. They are native to Madagascar, mainland Africa, and Australia. The trees have also been introduced to other regions such as Asia. A genomic and ecological analysis has suggested that the genus is Madagascan in origin.
The generic name honours Michel Adanson, the French naturalist and explorer who described Adansonia digitata. The baobab is also known as the "upside down tree", a name that originates from several myths. They are among the most long-lived of vascular plants and have large flowers that are reproductive for a maximum of 15 hours. The flowers open around dusk, opening so quickly that movement can be detected by the naked eye, and are faded by the next morning. The fruits are large, oval to round and berry-like and hold kidney-shaped seeds in a dry, pulpy matrix. (Full article...)General images
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