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 evolved around 370 million years ago, and it is estimated that there are around three trillion mature trees in the world currently.
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 the trunk 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...)
The United Kingdom, being in the British Isles, is ideal for tree growth, thanks to its mild winters, plentiful rainfall, fertile soil and hill-sheltered topography. In the absence of people, much of Great Britain would be covered with mature oaks as well as savannah-type of plains, except for Scotland. Although conditions for forestry are good, trees face threats from fungi, parasites and pests. Nowadays, about 13% of Britain's land surface is wooded. European countries average 39%, but this varies widely from 1% (Malta) to 66% (Finland). As of 2021, government plans call for 30,000 hectares to be reforested each year.[needs update] Efforts to reach these targets have attracted criticism for planting non-native trees, or trees that are out of place for their surroundings, leading to ecological changes.
The UK's supply of timber was depleted during the First and Second World Wars, when imports were difficult, and the forested area bottomed out at under 5% of Britain's land surface in 1919. That year, the Forestry Commission was established to produce a strategic reserve of timber. (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?
Selected article -
The coconut tree (Cocos nucifera) is a member of the palm tree family (Arecaceae) and the only living species of the genus Cocos. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the fruit, which botanically is a drupe, not a nut. They are ubiquitous in coastal tropical regions and are a cultural icon of the tropics.
The coconut tree provides food, fuel, cosmetics, folk medicine and building materials, among many other uses. The inner flesh of the mature seed, as well as the coconut milk extracted from it, forms a regular part of the diets of many people in the tropics and subtropics. Coconuts are distinct from other fruits because their endosperm contains a large quantity of an almost clear liquid, called "coconut water" or "coconut juice". Mature, ripe coconuts can be used as edible seeds, or processed for oil and plant milk from the flesh, charcoal from the hard shell, and coir from the fibrous husk. Dried coconut flesh is called copra, and the oil and milk derived from it are commonly used in cooking – frying in particular – as well as in soaps and cosmetics. Sweet coconut sap can be made into drinks or fermented into palm wine or coconut vinegar. The hard shells, fibrous husks and long pinnate leaves can be used as material to make a variety of products for furnishing and decoration. (Full article...)General images
Selected lists
Subcategories
Related portals
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikispecies
Directory of species -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus