Portal:Trees
The Trees Portal
In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. 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 taxonomic group but include a variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. 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 some three trillion mature trees in the world.
A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk 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 parts 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...)
Recognized content - 
Betula pubescens (syn. Betula alba), commonly known as downy birch and also as moor birch, white birch, European white birch or hairy birch, is a species of deciduous tree, native and abundant throughout northern Europe and northern Asia, growing farther north than any other broadleaf tree. It is closely related to, and often confused with, the silver birch (B. pendula), but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch (B. nana).
Three varieties are recognised and it hybridises with the silver and dwarf birches. A number of cultivars have been developed but many are no longer in cultivation. The larva of the autumnal moth (Epirrita autumnata) feeds on the foliage and in some years, large areas of birch forest can be defoliated by this insect. Many fungi are associated with the tree and certain pathogenic fungi are the causal agents of birch dieback disease. (Full article...)Did you know? -
- ... 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?
Selected article -
The existence of a wood economy, or more broadly, a forest economy (in many countries a bamboo economy predominates), is a prominent matter in many developing countries as well as in many other nations with a temperate climate and especially in those with low temperatures. These are generally the countries with greater forested areas. The uses of wood in furniture, buildings, bridges, and as a source of energy are widely known. Additionally, wood from trees and bushes, can be turned into a variety of production, such as wood pulp, cellulose in paper, celluloid in early photographic film, cellophane, and rayon (a substitute for silk).
At the end of their normal usage, wood products can be burnt to obtain thermal energy or can be used as a fertilizer. The potential environmental damage that a wood economy could occasion include a reduction of biodiversity due to monoculture forestry (the intensive cultivation of very few trees types); and CO2 emissions. However, forests can aid in the reduction of atmospheric carbon dioxide and therefore decrease global warming. (Full article...)General images
Since 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.
Northern beech (Fagus sylvatica) trunk in autumn
Priest 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
Dormant Magnolia bud
A forest near Vinitsa, North Macedonia
Diagram 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.
Forest on Mount Dajt, Albania
Buttress roots of the kapok tree (Ceiba pentandra)
Alleé of London plane trees (Platanus × acerifolia) in garden
Tall herbaceous monocotyledonous plants such as banana lack secondary growth, but are trees under the broadest definition.
Latvian Pine Forest in Ķegums Municipality
Broadleaf forest in Bhutan
Tywi Forest, Wales
Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation
Taiga forest near Saranpaul in the northeast Ural Mountains, Khanty–Mansia, Russia. Trees include Picea obovata (dominant on right bank), Larix sibirica, Pinus sibirica, and Betula pendula.
Roof trusses made from softwood
Sugar maple (Acer saccharum) tapped to collect sap for maple syrup
Proportion and distribution of global forest area by climatic domain, 2020
The Adirondack Mountains of Upstate New York form the southernmost part of the Eastern forest-boreal transition ecoregion.
Selling firewood at a market
Form, leaves and reproductive structures of queen sago (Cycas circinalis)
Proportion of forest in protected areas, by region, 2020
Trees in art: Weeping Willow, Claude Monet, 1918
Latex collecting from a rubber tree (Hevea brasiliensis)
Lepidodendron, an extinct lycophyte tree
Yggdrasil, the World Ash of Norse mythology
Redwood tree in northern California redwood forest, where many redwood trees are managed for preservation and longevity, rather than being harvested for wood production
A young red pine (Pinus resinosa) with spread of roots visible, as a result of soil erosion
Buds, leaves, flowers and fruit of oak (Quercus robur)
Palms and cycads as they might have appeared in the middle Tertiary
Forest in the Scottish Highlands
Buds, leaves and reproductive structures of white fir (Abies alba)
Even, 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.
Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree
People trees, by Pooktre
A conifer forest in the Swiss Alps (National Park)
A dry sclerophyll forest in Sydney, which is dominated by eucalyptus trees.
European larch (Larix decidua), a coniferous tree which is also deciduous
Biogradska forest in Montenegro
Recently stripped cork oak (Quercus suber)
Conifers in the Swabian alps
Temperate rainforest in Tasmania's Hellyer Gorge
The General Sherman Tree, thought to be the world's largest by volume
.jpg)
.jpg)
