Portal:Trees

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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...)

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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...)

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... that the Top 10 New Species of the past year include a 40 foot (12 m) tall tree (pictured), a crustacean that looks like a skeleton, a protist that acts like a sponge, and a fungus named after the King of the Netherlands?
... that the Pass Christian Light was deactivated in part because neighboring property owners refused to trim their trees?
... that Cossinia trifoliata trees endemic to New Caledonia have become vulnerable to extinction, according to the International Union for Conservation of Nature's 1998 assessment?
... that the Hanlon Expressway is named after Felix Hanlon, who helped cut the first tree to inaugurate Guelph, Ontario?
... that British architect Richard Feilden was killed by a falling tree whilst creating a woodland memorial for his recently deceased father?
... that according to tradition the Church of the Holy Archangels, Rogoz was built from two huge elm trees?
... that the oak tree under which Goethe allegedly wrote Faust's Walpurgis Night scene stood inside Buchenwald concentration camp and was sketched by French Volontaires de la Liberté member and camp inmate Léon Delarbre?

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Adansonia digitata in Tanzania

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...)

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General images

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

Image 1Broadleaf forest in Bhutan (from Forest)
Image 2Even, 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 3Wind dispersed seed of elm (Ulmus), ash (Fraxinus) and maple (Acer) (from Tree)
Image 4Temperate rainforest in Tasmania's Hellyer Gorge (from Forest)
Image 5Malus sylvestris (from List of trees of Great Britain and Ireland)
Image 6Recently stripped cork oak (Quercus suber) (from Tree)
Image 7Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree (from Tree)
Image 8Neem tree at Sant Nenuram Ashram (from Trees of Pakistan)
Image 9European larch (Larix decidua), a coniferous tree which is also deciduous (from Tree)
Image 10Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation (from Forest)
Image 11A section of yew (Taxus baccata) showing 27 annual growth rings, pale sapwood and dark heartwood (from Tree)
Image 12Diagram 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 13Informal upright style of bonsai on a juniper tree (from Tree)
Image 14Rowan tree in Wicklow, Ireland (from List of trees of Great Britain and Ireland)
Image 15The Daintree Rainforest (from Tree)
Image 16Buttress roots of the kapok tree (Ceiba pentandra) (from Tree)
Image 17Trees in art: Weeping Willow, Claude Monet, 1918 (from Tree)
Image 18Palms and cycads as they might have appeared in the middle Tertiary (from Tree)
Image 19Cracked thorny skin of a Aesculus tree seed (from Tree)
Image 20Proportion and distribution of global forest area by climatic domain, 2020 (from Forest)
Image 21Redwood 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 224000 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 23A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion (from Tree)
Image 24World production of selected forest products (from Forest)
Image 25Dormant Magnolia bud (from Tree)
Image 26Share of land that is covered by forest (from Forest)
Image 27Sugar maple (Acer saccharum) tapped to collect sap for maple syrup (from Tree)
Image 28Burned forest on Thasos (from Forest)
Image 29Proportion of forest in protected areas, by region, 2020 (from Forest)
Image 30Conifers in the Swabian alps (from Tree)
Image 31Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition. (from Tree)
Image 32Form, leaves and reproductive structures of queen sago (Cycas circinalis) (from Tree)
Image 33Buds, leaves and reproductive structures of white fir (Abies alba) (from Tree)
Image 34Alleé of London plane trees (Platanus × acerifolia) in garden (from Tree)
Image 35Selling firewood at a market (from Tree)
Image 36Yggdrasil, the World Ash of Norse mythology (from Tree)
Image 37Fraxinus excelsior (from List of trees of Great Britain and Ireland)
Image 38Garibaldi Provincial Park, British Columbia (from Forest)
Image 39Lepidodendron, an extinct lycophyte tree (from Tree)
Image 40Northern beech (Fagus sylvatica) trunk in autumn (from Tree)
Image 41Share of forest area in total land area, top countries (2021) (from Forest)
Image 42Priest 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)
Image 43A forest near Vinitsa, North Macedonia (from Forest)
Image 44Forest in the Scottish Highlands (from Forest)
Image 45Olive trees in Pakistan (from Trees of Pakistan)
Image 46Latvian Pine Forest in Ķegums Municipality (from Forest)
Image 47Alnus glutinosa (from List of trees of Great Britain and Ireland)
Image 48Roof trusses made from softwood (from Tree)
Image 49The Amazon rainforest alongside the Solimões River, a tropical rainforest. These forests are the most biodiverse and productive ecosystems in the world. (from Forest)
Image 50People trees, by Pooktre (from Tree)
Image 51The General Sherman Tree, thought to be the world's largest by volume (from Tree)
Image 52Buds, leaves, flowers and fruit of oak (Quercus robur) (from Tree)
Image 53Latex collecting from a rubber tree (Hevea brasiliensis) (from Tree)
Image 54Since 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)