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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Brachychiton rupestris (commonly known as the narrow-leaved bottle tree or Queensland bottle tree) is a tree in the family Malvaceae, endemic to Queensland, Australia. Described by Sir Thomas Mitchell and John Lindley in 1848, it earned its name from its bulbous trunk, which can be up to 3.5 metres (11 ft) in diameter at breast height (DBH). Reaching around 10–25 metres (33–82 ft) high, the Queensland bottle tree is deciduous, losing its leaves seasonally, between September and December. The leaves are simple or divided, with one or more narrow leaf blades up to 11 centimetres (4 in) long and 2 centimetres (0.8 in) wide. Cream-coloured flowers appear from September to November, and are followed by woody, boat-shaped follicles that ripen from November to May. No subspecies are recognised.

As a drought deciduous succulent tree, much like the baobab (Adansonia) of Madagascar, B. rupestris adapts readily to cultivation, and is quite tolerant of a range of soils and temperatures. It is a key component and emergent tree in the endangered central semi-evergreen vine thickets (also known as bottletree scrub) of the Queensland Brigalow Belt. Remnant trees are often left by farmers on cleared land for their value as shade and fodder trees, and as homes for various birds and animals. (Full article...)

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... that fossil leaves almost identical to those of the Australian rainforest tree Orites excelsus (pictured) have been found in New Zealand?
... that more than 8000 trees were planted in Backmuir Wood to celebrate the 2000 millennium?
... that the name of the newly defined genus of macadamia-like trees, Lasjia, is derived from the initials of Lawrence Alexander Sidney Johnson?
... that at St Athan, a wild fig tree grew out of the cement of the East Orchard chapel walls?
... that in the churchyard of St Mary and St Peter's Church in Wilmington, East Sussex, there is a 1,600-year-old, 23-foot (7 m) wide yew tree?
... that Christopher Werner made a lifelike South Carolina Palmetto tree out of iron, copper, and brass?
... that seed from an endangered Chrysophyllum imperiale tree planted in Royal Botanic Gardens, Sydney in 1868 by Prince Alfred has been sent to its native Brazil to aid in recovering the species there?

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A branch collar is the "shoulder" between the branch and trunk of woody plants; the inflammation formed at the base of the branch is caused by annually overlapping trunk tissue. The shape of the branch collar is due to two separate growth patterns, initially the branch grows basipetally, followed by seasonal trunk growth which envelops the branch.

Branch collars serve as a strong foundation to the branch, and its orientation and internal characteristics allow the branch to withstand stress from numerous directions. Functionally the branch collars also influence the conductivity of nutrients and growth patterns. (Full article...)

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General images

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

Image 1Informal upright style of bonsai on a juniper tree (from Tree)
Image 2Burned forest on Thasos (from Forest)
Image 3Broadleaf forest in Bhutan (from Forest)
Image 4Trees in art: Weeping Willow, Claude Monet, 1918 (from Tree)
Image 5Olive trees in Pakistan (from Trees of Pakistan)
Image 6Conifers in the Swabian alps (from Tree)
Image 7Neem tree at Sant Nenuram Ashram (from Trees of Pakistan)
Image 8Share of forest area in total land area, top countries (2021) (from Forest)
Image 9European larch (Larix decidua), a coniferous tree which is also deciduous (from Tree)
Image 10The General Sherman Tree, thought to be the world's largest by volume (from Tree)
Image 11Lepidodendron, an extinct lycophyte tree (from Tree)
Image 12Even, 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 13Sugar maple (Acer saccharum) tapped to collect sap for maple syrup (from Tree)
Image 14People trees, by Pooktre (from Tree)
Image 15Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree (from Tree)
Image 16A forest near Vinitsa, North Macedonia (from Forest)
Image 17A section of yew (Taxus baccata) showing 27 annual growth rings, pale sapwood and dark heartwood (from Tree)
Image 18Latvian Pine Forest in Ķegums Municipality (from Forest)
Image 19Forest in the Scottish Highlands (from Forest)
Image 20Since 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 21Dormant Magnolia bud (from Tree)
Image 22Cracked thorny skin of a Aesculus tree seed (from Tree)
Image 23Buds, leaves, flowers and fruit of oak (Quercus robur) (from Tree)
Image 24Palms and cycads as they might have appeared in the middle Tertiary (from Tree)
Image 25Fraxinus excelsior (from List of trees of Great Britain and Ireland)
Image 26Wind dispersed seed of elm (Ulmus), ash (Fraxinus) and maple (Acer) (from Tree)
Image 27The Amazon rainforest alongside the Solimões River, a tropical rainforest. These forests are the most biodiverse and productive ecosystems in the world. (from Forest)
Image 28Proportion of forest in protected areas, by region, 2020 (from Forest)
Image 29Malus sylvestris (from List of trees of Great Britain and Ireland)
Image 30The Daintree Rainforest (from Tree)
Image 31Selling firewood at a market (from Tree)
Image 324000 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 33Share of land that is covered by forest (from Forest)
Image 34Alnus glutinosa (from List of trees of Great Britain and Ireland)
Image 35Buds, leaves and reproductive structures of white fir (Abies alba) (from Tree)
Image 36Recently stripped cork oak (Quercus suber) (from Tree)
Image 37Latex collecting from a rubber tree (Hevea brasiliensis) (from Tree)
Image 38Priest 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 39Temperate rainforest in Tasmania's Hellyer Gorge (from Forest)
Image 40Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation (from Forest)
Image 41Diagram 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 42Alleé of London plane trees (Platanus × acerifolia) in garden (from Tree)
Image 43Buttress roots of the kapok tree (Ceiba pentandra) (from Tree)
Image 44Redwood 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 45A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion (from Tree)
Image 46Northern beech (Fagus sylvatica) trunk in autumn (from Tree)
Image 47Roof trusses made from softwood (from Tree)
Image 48World production of selected forest products (from Forest)
Image 49Yggdrasil, the World Ash of Norse mythology (from Tree)
Image 50Rowan tree in Wicklow, Ireland (from List of trees of Great Britain and Ireland)
Image 51Garibaldi Provincial Park, British Columbia (from Forest)
Image 52Proportion and distribution of global forest area by climatic domain, 2020 (from Forest)
Image 53Form, leaves and reproductive structures of queen sago (Cycas circinalis) (from Tree)
Image 54Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition. (from Tree)