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 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...)

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Betula pendula, commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found at higher altitudes. Its range extends into Siberia, China, and southwest Asia in the mountains of northern Turkey, the Caucasus, and northern Iran. It has been introduced into North America, where it is known as the European white birch or weeping birch and is considered invasive in some states in the United States and parts of Canada. The tree can also be found in more temperate regions of Australia.

The silver birch is a medium-sized deciduous tree that owes its common name to the white peeling bark on the trunk. The twigs are slender and often pendulous and the leaves are roughly triangular with doubly serrate margins and turn yellow and brown in autumn before they fall. The flowers are catkins and the light, winged seeds get widely scattered by the wind. The silver birch is a hardy tree, a pioneer species, and one of the first trees to appear on bare or fire-swept land. Many species of birds and animals are found in birch woodland, the tree supports a wide range of insects and the light shade it casts allows shrubby and other plants to grow beneath its canopy. It is planted decoratively in parks and gardens and is used for forest products such as joinery timber, firewood, tanning, racecourse jumps, and brooms. Various parts of the tree are used in traditional medicine and the bark contains triterpenes, which have been shown to have medicinal properties. (Full article...)

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... that Gregory's tree (pictured), near Timber Creek in Australia's Northern Territory, bears inscriptions by 19th-century explorers and is registered as both a heritage place and an Aboriginal sacred site?
... that the Balderschwang Yew is possibly the oldest tree in Germany?
... that black truffles suppress plant growth around their host tree, creating an area that looks burned?
... that root extracts from the tree species Pycnanthus angolensis can be used to treat parasitic infections, such as schistosomiasis?
... that the lime trees of Duncliffe Wood are reputedly among the oldest living things in the county of Dorset?
... that trees of the New Guinea genus Finschia have stilt roots coming off the trunk up to 1.8 m (6 ft) off the ground?
... that in the early 1980s, a team of surveyors discovered the World War II-era Avro Anson Memorial near Clackline, Western Australia, which had been overgrown by shrubs and trees?

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Norway spruce (Picea abies)

A spruce is a tree of the genus Picea (/paɪˈsiː.ə/ py-SEE-ə), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. Picea is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m (about 60–200 ft) tall when mature, and have whorled branches and conical form.

Spruces can be distinguished from other genera of the family Pinaceae by their needles (leaves), which are four-sided and attached singly to small persistent peg-like structures (pulvini or sterigmata) on the branches, and by their cones (without any protruding bracts), which hang downwards after they are pollinated. The needles are shed when 4–10 years old, leaving the branches rough with the retained pegs. In other similar genera, the branches are fairly smooth. (Full article...)

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General images

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

Image 1Yellow cassia, an ornamental tree with yellow flowers (from Tree)
Image 2Share of land that is covered by forest (from Forest)
Image 3Dormant buds of ash, Fraxinus excelsior (from Tree)
Image 4Malus sylvestris (from List of trees of Great Britain and Ireland)
Image 5Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation (from Forest)
Image 6Olive trees in Pakistan (from Trees of Pakistan)
Image 7Northern beech (Fagus sylvatica) trunk in autumn (from Tree)
Image 8European larch (Larix decidua), a coniferous tree which is also deciduous (from Tree)
Image 9An avenue of London planes (Platanus × hispanica) in a garden in Belgium. (from Tree)
Image 10The Amazon rainforest alongside the Solimões River, a tropical rainforest. These forests are the most biodiverse and productive ecosystems in the world. (from Forest)
Image 11Since 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 12Palms and cycads as they might have appeared in the middle Tertiary (from Tree)
Image 13Temperate rainforest in Tasmania's Hellyer Gorge (from Forest)
Image 14Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree (from Tree)
Image 15A forest near Vinitsa, North Macedonia (from Forest)
Image 16Garibaldi Provincial Park, British Columbia (from Forest)
Image 17Sugar maple (Acer saccharum) tapped to collect sap for maple syrup (from Tree)
Image 18A section of yew (Taxus baccata) showing 27 annual growth rings, pale sapwood and dark heartwood (from Tree)
Image 19Neem tree at Sant Nenuram Ashram (from Trees of Pakistan)
Image 20The Daintree Rainforest (from Tree)
Image 21Buds, leaves and reproductive structures of white fir, Abies alba (from Tree)
Image 22Buds, leaves, flowers and fruit of pedunculate oak, Quercus robur (from Tree)
Image 23Conifers in the Swabian alps (from Tree)
Image 24Trees in art: Weeping Willow, Claude Monet, 1918 (from Tree)
Image 25Rowan tree in Wicklow, Ireland (from List of trees of Great Britain and Ireland)
Image 26Roof trusses made from softwood (from Tree)
Image 27Even, 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 28Informal upright style of bonsai on a juniper tree (from Tree)
Image 29Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition. (from Tree)
Image 30The General Sherman Tree, thought to be the world's largest by volume (from Tree)
Image 31Selling firewood at a market (from Tree)
Image 32Recently stripped cork oak (Quercus suber) (from Tree)
Image 33Alnus glutinosa (from List of trees of Great Britain and Ireland)
Image 34Latex collecting from a rubber tree (Hevea brasiliensis) (from Tree)
Image 35Casentinesi Forests, Italy (from Forest)
Image 36Redwood 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 37World production of selected forest products (from Forest)
Image 38Latvian Pine Forest in Ķegums Municipality (from Forest)
Image 39Share of forest area in total land area, top countries (2021) (from Forest)
Image 40Broadleaf forest in Bhutan (from Forest)
Image 41Lepidodendron, an extinct lycophyte tree (from Tree)
Image 42Proportion and distribution of global forest area by climatic domain, 2020 (from Forest)
Image 43Forest in the Scottish Highlands (from Forest)
Image 44Cracked thorny skin of a Aesculus tree seed (from Tree)
Image 45Proportion of forest in protected areas, by region, 2020 (from Forest)
Image 46Wind dispersed seed of elm (Ulmus), ash (Fraxinus) and maple (Acer) (from Tree)
Image 47Yggdrasil, the World Ash of Norse mythology (from Tree)
Image 48People trees, by Pooktre (from Tree)
Image 494000 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 50Form, leaves and reproductive structures of queen sago, Cycas circinalis (from Tree)
Image 51Buttress roots of the kapok tree (Ceiba pentandra) (from Tree)
Image 52Fraxinus excelsior (from List of trees of Great Britain and Ireland)
Image 53Priest 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 54A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion (from Tree)
Image 55Diagram 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 56Burned forest on Thasos (from Forest)