Portal:Trees

Portal topics: Activities; Culture; Geography; Health; History; Mathematics; Nature; People; Philosophy; Religion; Society; Technology; Random portal

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. Flowering plants have their seeds inside fruits, while conifers carry their seeds in cones, and 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...)

Refresh with new selections below (purge)

Recognized content - show another

Entries here consist of Good and Featured articles, which meet a core set of high editorial standards.

The canopy of Simarouba amara

Simarouba amara is a species of tree in the family Simaroubaceae, found in the rainforests and savannahs of South and Central America and the Caribbean. It was first described by Aubl. in French Guiana in 1775 and is one of six species of Simarouba. The tree is evergreen, but produces a new set of leaves once a year. It requires relatively high levels of light to grow and grows rapidly in these conditions, but lives for a relatively short time. In Panama, it flowers during the dry season in February and March, whereas in Costa Rica, where there is no dry season it flowers later, between March and July. As the species is dioecious, the trees are either male or female and only produce male or female flowers. The small yellow flowers are thought to be pollinated by insects, the resulting fruits are dispersed by animals including monkeys, birds and fruit-eating bats and the seeds are also dispersed by leaf cutter ants.

Simarouba amara has been studied extensively by scientists in an attempt to understand the tree and also to gain a better understanding of the ecology of the rainforest in general. Many of these studies were conducted on Barro Colorado Island in Panama or at La Selva Biological Station in Costa Rica. Of particular interest is how it competes with other species and with individuals of the same species at different stages in its life cycle. The seedlings are normally limited by the amount of light and nutrients found where they are growing and the saplings are considered relatively light demanding compared to other species. Young individuals are more likely to survive when they grow further away from their parents and when there are few other individuals growing near to them, which may be due to them being able to escape diseases. Plant physiologists have investigated how the leaves of the tree differ depending on their location in the forest canopy finding they are thicker in the canopy and thinner in the understory. They have also measured how the water potential of their leaves changes and when their stomata open and close during the day; the findings suggest that rather than closing their stomata to control water loss, it is controlled by the leaf area instead. Population geneticists have examined the way in which its genes vary, at both the local scale and across its range using microsatellites. It is genetically diverse, indicating gene flow occurs between populations and seeds can be dispersed up to 1 km. The leaves of S. amara are eaten by several species of caterpillar, particularly those in the genus Atteva. Several species of termite and ants live on or around the tree and lianas and epiphytes grow on the tree. (Full article...)

List of recognized articles

Did you know? - show different entries

... that the Easter egg tree (pictured) in Saalfeld, Thuringia, was decorated with 10,000 Easter eggs in 2012?
... that the most popular species for Christmas trees in Denmark and most of Europe is the Nordmann fir?
... that seed of the African teak tree is largely dispersed by fruit bats?
... that Trichia decipiens live on deadwood of conifers and leaf trees all year around?
... that Aecidium mori causes mulberry rust disease on the mulberry flowering plant, which decreases the quantity of leaves on the trees?
... that the satinleaf tree is endangered in its native Florida, but an invasive weed in Hawaii?
... that the Brown Treecreeper spirals up and down tree trunks while foraging?

Start a new article

Selected article - show another

Forest rings are large, circular patterns of low tree density in the boreal forests of northern Canada. These rings can range from 50 metres (160 ft) to nearly 2 kilometres (1.2 mi) in diameter, with rims about 20 metres (66 ft) in thickness. The origin of forest rings is not known, despite several mechanisms for their creation having been proposed. Such hypotheses include radially growing fungus, buried kimberlite pipes, trapped gas pockets, and meteorite impact craters. (Full article...)

List of selected articles

General images

The following are images from various tree-related articles on Wikipedia.

Image 1Yggdrasil, the World Ash of Norse mythology (from Tree)
Image 2Forest in the Scottish Highlands (from Forest)
Image 3Latex collecting from a rubber tree (Hevea brasiliensis) (from Tree)
Image 4Burned forest on Thasos (from Forest)
Image 5Latvian Pine Forest in Ķegums Municipality (from Forest)
Image 6Yellow cassia, an ornamental tree with yellow flowers (from Tree)
Image 7Diagram of secondary growth in a eudicot or coniferous tree showing idealised vertical and horizontal sections. A new layer of wood is added in each growing season, thickening the stem, existing branches and roots. (from Tree)
Image 8Temperate rainforest in Tasmania's Hellyer Gorge (from Forest)
Image 9A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion (from Tree)
Image 10Neem tree at Sant Nenuram Ashram (from Trees of Pakistan)
Image 11Selling firewood at a market (from Tree)
Image 12Share of land that is covered by forest (from Forest)
Image 13Garibaldi Provincial Park, British Columbia (from Forest)
Image 14The Daintree Rainforest (from Tree)
Image 15Trees in art: Weeping Willow, Claude Monet, 1918 (from Tree)
Image 16Rowan tree in Wicklow, Ireland (from List of trees of Great Britain and Ireland)
Image 17Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree (from Tree)
Image 18European larch (Larix decidua), a coniferous tree which is also deciduous (from Tree)
Image 19A forest near Vinitsa, North Macedonia (from Forest)
Image 20Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation (from Forest)
Image 21Buttress roots of the kapok tree (Ceiba pentandra) (from Tree)
Image 22Redwood tree in northern California redwood forest, where many redwood trees are managed for preservation and longevity, rather than being harvested for wood production (from Forest)
Image 23Fraxinus excelsior (from List of trees of Great Britain and Ireland)
Image 24Broadleaf forest in Bhutan (from Forest)
Image 25Even, dense old-growth stand of beech trees (Fagus sylvatica) prepared to be regenerated by their saplings in the understory, in the Brussels part of the Sonian Forest. (from Forest)
Image 26Wind dispersed seed of elm (Ulmus), ash (Fraxinus) and maple (Acer) (from Tree)
Image 27Palms and cycads as they might have appeared in the middle Tertiary (from Tree)
Image 28Dormant buds of ash, Fraxinus excelsior (from Tree)
Image 29Malus sylvestris (from List of trees of Great Britain and Ireland)
Image 30World production of selected forest products (from Forest)
Image 31Proportion and distribution of global forest area by climatic domain, 2020 (from Forest)
Image 32An avenue of London planes (Platanus × hispanica) in a garden in Belgium. (from Tree)
Image 33Buds, leaves, flowers and fruit of pedunculate oak, Quercus robur (from Tree)
Image 34Buds, leaves and reproductive structures of white fir, Abies alba (from Tree)
Image 35The General Sherman Tree, thought to be the world's largest by volume (from Tree)
Image 36Roof trusses made from softwood (from Tree)
Image 37A section of yew (Taxus baccata) showing 27 annual growth rings, pale sapwood and dark heartwood (from Tree)
Image 38People trees, by Pooktre (from Tree)
Image 394000 years old Cypress of Abarqu is the oldest tree in Iran and the second oldest tree in the world. (from List of trees of Iran)
Image 40Conifers in the Swabian alps (from Tree)
Image 41Northern beech (Fagus sylvatica) trunk in autumn (from Tree)
Image 42Casentinesi Forests, Italy (from Forest)
Image 43Recently stripped cork oak (Quercus suber) (from Tree)
Image 44Cracked thorny skin of a Aesculus tree seed (from Tree)
Image 45Informal upright style of bonsai on a juniper tree (from Tree)
Image 46Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition. (from Tree)
Image 47Form, leaves and reproductive structures of queen sago, Cycas circinalis (from Tree)
Image 48Sugar maple (Acer saccharum) tapped to collect sap for maple syrup (from Tree)
Image 49Since the 13th century, the Niepołomice Forest in Poland has had special use and protection. In this view from space, different coloration can indicate different functions. (from Forest)
Image 50Lepidodendron, an extinct lycophyte tree (from Tree)
Image 51Share of forest area in total land area, top countries (2021) (from Forest)
Image 52Alnus glutinosa (from List of trees of Great Britain and Ireland)
Image 53Proportion of forest in protected areas, by region, 2020 (from Forest)
Image 54The Amazon rainforest alongside the Solimões River, a tropical rainforest. These forests are the most biodiverse and productive ecosystems in the world. (from Forest)
Image 55Olive trees in Pakistan (from Trees of Pakistan)
Image 56Priest River winding through Whitetail Butte with lots of forestry to the east—these lot patterns have existed since the mid-19th century. The white patches reflect areas with younger, smaller trees, where winter snow cover shows up brightly to the astronauts. Dark green-brown squares are parcels (from Forest)