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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Old Tjikko

Old Tjikko is an approximately 9,566 years-old Norway spruce, located in the Dalarna province in Sweden. Old Tjikko originally gained fame as the "world's oldest tree". Old Tjikko is, however, a clonal tree that has regenerated new trunks, branches and roots over millennia rather than an individual tree of great age. Old Tjikko is recognized as the oldest living Picea abies and the fourth-oldest known clonal tree.

The age of the tree was determined by carbon dating of genetically matched plant material collected from under the tree, as dendrochronology does not work for clonal trees. The trunk itself is estimated to be only a few centuries old, but the plant has survived for much longer due to a process known as layering (when a branch comes in contact with the ground, it sprouts a new root), or vegetative cloning (when the trunk dies but the root system is still alive, it may sprout a new trunk). (Full article...)

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... that veneration of the Amla tree (pictured), in particular on Amalaka Ekadashi, is due to the belief that the god Vishnu resides in and near the tree?
... that the future of the tropical tree Milicia regia for timber production is threatened by a gall fly, Phytolyma lata?
... that the churchyard of All Saints Church, Ulcombe in England contains a yew tree claimed to be more than 2,000 years old?
... that seeds of the extinct tree Eucommia eocenica have been found with latex covered fossils?
... that the fruits of the Lecythis ampla tree resemble little wooden pots with lids?
... that fossilized seeds of the extinct tree Eucommia montana are found from British Columbia to Colorado?
... that the Australian tree Agathis atropurpurea is known as the black kauri or the blue kauri because of the colour of its bark?

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Illegal logging has been a problem in Madagascar for decades and is perpetuated by extreme poverty and government corruption. Often taking the form of selective logging, the trade has been driven by high international demand for expensive, fine-grained lumber such as rosewood and ebony. Historically, logging and exporting in Madagascar have been regulated by the Malagasy government, although the logging of rare hardwoods was explicitly banned from protected areas in 2000. Since then, government orders and memos have intermittently alternated between permitting and banning exports of precious woods. The most commonly cited reason for permitting exports is to salvage valuable wood from cyclone damage, although this reasoning has come under heavy scrutiny. This oscillating availability of Malagasy rosewood and other precious woods has created a market of rising and falling prices, allowing traders or "timber barons" to stockpile illegally sourced logs during periodic bans and then flood the market when the trade windows open and prices are high. Over 350,000 trees were illegally felled in Madagascar between 2010 and 2015, according to TRAFFIC.

The unsustainable exploitation of these tropical hardwoods, particularly rosewood from the SAVA Region, has escalated significantly since the start of the 2009 Malagasy political crisis. Over 350,000 trees were illegally felled in Madagascar between 2010 and 2015, according to TRAFFIC. Thousands of poorly paid Malagasy loggers have flooded into the national parks—especially in the northeast—building roads, setting up logging camps, and cutting down even the most difficult to reach rosewood trees. Illegal activities are openly flaunted, armed militia have descended upon local villages, and a rosewood mafia easily bribes government officials, buying export permits with ease. These illegal operations are funded in part by advance payments for future shipments (financed by Chinese expatriates and Chinese importers) and by loans from large, international banks. Demand is fueled mostly by a growing Chinese middle class and their desire for exotic imperial-style furniture. European and American demand for high-end musical instruments and furniture have also played a role. However, public scrutiny has put significant pressure on shipping companies involved in the trade, and the United States is starting to enforce the Lacey Act by investigating companies with suspected involvement in the illegal trade of Malagasy precious woods. (Full article...)

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General images

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

Image 1European larch (Larix decidua), a coniferous tree which is also deciduous (from Tree)
Image 2Temperate rainforest in Tasmania's Hellyer Gorge (from Forest)
Image 3Northern beech (Fagus sylvatica) trunk in autumn (from Tree)
Image 4World production of selected forest products (from Forest)
Image 5Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree (from Tree)
Image 6The Daintree Rainforest (from Tree)
Image 7Yggdrasil, the World Ash of Norse mythology (from Tree)
Image 8Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition. (from Tree)
Image 9Olive trees in Pakistan (from Trees of Pakistan)
Image 10Conifers in the Swabian alps (from Tree)
Image 11Lepidodendron, an extinct lycophyte tree (from Tree)
Image 12A forest near Vinitsa, North Macedonia (from Forest)
Image 13Cracked thorny skin of a Aesculus tree seed (from Tree)
Image 14Garibaldi Provincial Park, British Columbia (from Forest)
Image 15The General Sherman Tree, thought to be the world's largest by volume (from Tree)
Image 16Buds, leaves, flowers and fruit of pedunculate oak, Quercus robur (from Tree)
Image 17An avenue of London planes (Platanus × hispanica) in a garden in Belgium. (from Tree)
Image 18Wind dispersed seed of elm (Ulmus), ash (Fraxinus) and maple (Acer) (from Tree)
Image 19Forest in the Scottish Highlands (from Forest)
Image 20Form, leaves and reproductive structures of queen sago, Cycas circinalis (from Tree)
Image 21Even, 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 22Buds, leaves and reproductive structures of white fir, Abies alba (from Tree)
Image 23Rowan tree in Wicklow, Ireland (from List of trees of Great Britain and Ireland)
Image 24Broadleaf forest in Bhutan (from Forest)
Image 25A section of yew (Taxus baccata) showing 27 annual growth rings, pale sapwood and dark heartwood (from Tree)
Image 26Redwood 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 27Since 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 28Palms and cycads as they might have appeared in the middle Tertiary (from Tree)
Image 294000 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 30Neem tree at Sant Nenuram Ashram (from Trees of Pakistan)
Image 31The Amazon rainforest alongside the Solimões River, a tropical rainforest. These forests are the most biodiverse and productive ecosystems in the world. (from Forest)
Image 32People trees, by Pooktre (from Tree)
Image 33Diagram 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 34Share of forest area in total land area, top countries (2021) (from Forest)
Image 35Casentinesi Forests, Italy (from Forest)
Image 36Burned forest on Thasos (from Forest)
Image 37Fraxinus excelsior (from List of trees of Great Britain and Ireland)
Image 38Roof trusses made from softwood (from Tree)
Image 39Proportion of forest in protected areas, by region, 2020 (from Forest)
Image 40A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion (from Tree)
Image 41Dormant buds of ash, Fraxinus excelsior (from Tree)
Image 42Malus sylvestris (from List of trees of Great Britain and Ireland)
Image 43Trees in art: Weeping Willow, Claude Monet, 1918 (from Tree)
Image 44Informal upright style of bonsai on a juniper tree (from Tree)
Image 45Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation (from Forest)
Image 46Priest 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 47Latvian Pine Forest in Ķegums Municipality (from Forest)
Image 48Sugar maple (Acer saccharum) tapped to collect sap for maple syrup (from Tree)
Image 49Recently stripped cork oak (Quercus suber) (from Tree)
Image 50Yellow cassia, an ornamental tree with yellow flowers (from Tree)
Image 51Selling firewood at a market (from Tree)
Image 52Latex collecting from a rubber tree (Hevea brasiliensis) (from Tree)
Image 53Share of land that is covered by forest (from Forest)
Image 54Proportion and distribution of global forest area by climatic domain, 2020 (from Forest)
Image 55Buttress roots of the kapok tree (Ceiba pentandra) (from Tree)
Image 56Alnus glutinosa (from List of trees of Great Britain and Ireland)