Tree

Common ash (Fraxinus excelsior), a deciduous broad-leaved (angiosperm) tree
European larch (Larix decidua), a coniferous tree which is also deciduous

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. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody 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. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world.[1]

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.

Definition

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.

Although "tree" is a term of common parlance, there is no universally recognised precise definition of what a tree is, either botanically or in common language.[2] In its broadest sense, a tree is any plant with the general form of an elongated stem, or trunk, which supports the photosynthetic leaves or branches at some distance above the ground.[3] Trees are also typically defined by height,[4] with smaller plants from 0.5 to 10 m (1.6 to 32.8 ft) being called shrubs,[5] so the minimum height of a tree is only loosely defined.[4] Large herbaceous plants such as papaya and bananas are trees in this broad sense.[2][6]

A commonly applied narrower definition is that a tree has a woody trunk formed by secondary growth, meaning that the trunk thickens each year by growing outwards, in addition to the primary upwards growth from the growing tip.[4][7] Under such a definition, herbaceous plants such as palms, bananas and papayas are not considered trees regardless of their height, growth form or stem girth. Certain monocots may be considered trees under a slightly looser definition;[8] while the Joshua tree, bamboos and palms do not have secondary growth and never produce true wood with growth rings,[9][10] they may produce "pseudo-wood" by lignifying cells formed by primary growth.[11]

Aside from structural definitions, trees are commonly defined by use; for instance, as those plants which yield lumber.[12]

Other Languages
Afrikaans: Boom
Alemannisch: Baum
አማርኛ: ዛፍ
Ænglisc: Trēow
العربية: شجرة
aragonés: Árbol
ܐܪܡܝܐ: ܐܝܠܢܐ
armãneashti: Arburi
অসমীয়া: বৃক্ষ
asturianu: Árbol
Avañe'ẽ: Yvyra
Aymar aru: Quqa
azərbaycanca: Ağac (bitki)
تۆرکجه: آغاج
bamanankan: Yiri
বাংলা: বৃক্ষ
Bân-lâm-gú: Chhiū
башҡортса: Ағас
беларуская: Дрэва
беларуская (тарашкевіца)‎: Дрэва
भोजपुरी: फेड़
български: Дърво
Boarisch: Baam
བོད་ཡིག: ཤིང་།
bosanski: Drvo (stablo)
brezhoneg: Gwez (plant)
буряад: Модон
català: Arbre
Чӑвашла: Йывăç
čeština: Strom
chiShona: Muti
Cymraeg: Coeden
Deitsch: Baam
Deutsch: Baum
eesti: Puu
Ελληνικά: Δέντρο
emiliàn e rumagnòl: Élber
эрзянь: Чувтт
español: Árbol
Esperanto: Arbo
euskara: Zuhaitz
eʋegbe: Atí
فارسی: درخت
føroyskt: Trø
français: Arbre
Frysk: Beam
furlan: Arbul
Gaeilge: Crann
Gaelg: Billey
Gàidhlig: Craobh
galego: Árbore
贛語:
客家語/Hak-kâ-ngî: Su (chhṳ̍t-vu̍t)
한국어: 나무
Hausa: Bishiya
հայերեն: Ծառ
हिन्दी: वृक्ष
hrvatski: Stablo
Ido: Arboro
Ilokano: Kayo
Bahasa Indonesia: Pohon
interlingua: Arbore
Iñupiak: Napaaqtuq
Ирон: Бæлас
isiXhosa: Umthi
íslenska: Tré
italiano: Albero
עברית: עץ
Basa Jawa: Wit
ಕನ್ನಡ: ಮರ
Kapampangan: Pun dutung
ქართული: ხე
қазақша: Ағаш
kernowek: Gwydh
Kinyarwanda: Igiti
Kiswahili: Mti
коми: Пу
Kreyòl ayisyen: Pyebwa
kurdî: Dar
Кыргызча: Дарак
лакку: Мурхь
Latina: Arbor
latviešu: Koks
Lëtzebuergesch: Bam
лезги: Ттар
lietuvių: Medis
Limburgs: Boum
lingála: Nzeté
lumbaart: Alber
македонски: Дрво (растение)
മലയാളം: വൃക്ഷം
Māori: Rākau
मराठी: झाड
مازِرونی: دار
Bahasa Melayu: Pokok
Mìng-dĕ̤ng-ngṳ̄: Chéu
Mirandés: Arble
монгол: Мод
မြန်မာဘာသာ: သစ်ပင်
Nāhuatl: Cuahuitl
Nederlands: Boom (plant)
Nēhiyawēwin / ᓀᐦᐃᔭᐍᐏᐣ: ᒥᔥᑎᒄ
नेपाली: रूख
नेपाल भाषा: सिमा
日本語:
нохчийн: Дитт
Nordfriisk: Buum
norsk: Tre
norsk nynorsk: Tre
Nouormand: Bouais
occitan: Arbre
олык марий: Пушеҥге
oʻzbekcha/ўзбекча: Daraxt
ਪੰਜਾਬੀ: ਰੁੱਖ
پنجابی: رکھ
پښتو: ونه
Patois: Chrii
Picard: Ape
Tok Pisin: Diwai
Plattdüütsch: Boom
polski: Drzewo
português: Árvore
română: Arbore
Romani: Rukh
Runa Simi: Sach'a
русский: Дерево
саха тыла: Мас
ᱥᱟᱱᱛᱟᱲᱤ: ᱫᱟᱨᱮ
संस्कृतम्: तरुः
Scots: Tree
Seeltersk: Boom
sicilianu: Àrvulu
සිංහල: ගස්
Simple English: Tree
سنڌي: وڻ
slovenčina: Strom
slovenščina: Drevo
ślůnski: Strům
Soomaaliga: Geed
کوردی: دار
српски / srpski: Дрво
srpskohrvatski / српскохрватски: Stablo
Basa Sunda: Tangkal
suomi: Puu
svenska: Träd
Tagalog: Puno
தமிழ்: மரம்
Taqbaylit: Ttejṛa
tarandíne: Àrvule
татарча/tatarça: Агач
తెలుగు: చెట్టు
тоҷикӣ: Дарахт
ᏣᎳᎩ: ᏡᎬ
Tsetsêhestâhese: Hoohtsêstse
Türkçe: Ağaç
Türkmençe: Agaç
удмурт: Писпу
українська: Дерево
اردو: درخت
Vahcuengh: Faex
vèneto: Àlbaro
vepsän kel’: Pu
Tiếng Việt: Cây thân gỗ
Võro: Puu
walon: Åbe
Winaray: Puno
Wolof: Garab
吴语:
ייִדיש: בוים
粵語:
Zazaki: Dare
žemaitėška: Medis
中文: