View source for Forest

{{Short description|Dense collection of trees covering a relatively large area}}
{{About|a community of trees}}
{{Broader|Plant community}}
{{Not to be confused with|Woodland}}
{{pp-semi-indef|small=yes}}
{{Use dmy dates|date=January 2023}}
[[File:Aerial view of the Amazon Rainforest.jpg|thumb|upright=1.4|The [[Amazon rainforest]] alongside the [[Solimões River]], a [[tropical rainforest]]. These forests are the most [[biodiverse]] and productive [[Ecosystem|ecosystems]] in the world.]]
[[File:Proportion and distribution of global forest area by climatic domain, 2020.svg|thumb|upright=1.4|Proportion and distribution of global forest area by climatic domain, 2020<ref>{{Cite book|doi=10.4060/ca8753en|title=Global Forest Resources Assessment 2020 – Key findings|publisher=FAO|year=2020|isbn=978-92-5-132581-0|location=Rome|s2cid=130116768}}</ref>]]

A '''forest''' is an [[ecosystem]] characterized by a dense [[ecological community|community]] of [[tree]]s.<ref>{{cite web |url=http://dictionary.reference.com/browse/forest |title=Forest |website=Dictionary.com |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20141019171930/http://dictionary.reference.com/browse/forest |archive-date=19 October 2014}}</ref> Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function.<ref>{{cite web |url=http://www.efi.int/files/attachments/publications/ir_06.pdf |title=Compilation of Forestry Terms and Definitions |first1=Andreas |last1=Schuck |first2=Risto |last2=Päivinen |first3=Tuomo |last3=Hytönend |first4=Brita |last4=Pajari |publisher=[[European Forest Institute]] |location=Joensuu, Finland |year=2002 |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20150605064820/http://www.efi.int/files/attachments/publications/ir_06.pdf |archive-date=5 June 2015}}</ref><ref name="cbd">{{cite web |url=http://www.cbd.int/forest/definitions.shtml |title=Definitions: Indicative definitions taken from the Report of the ad hoc technical expert group on forest biological diversity |date=30 November 2006 |publisher=[[Convention on Biological Diversity]] |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20141219030427/http://www.cbd.int/forest/definitions.shtml |archive-date=19 December 2014}}</ref><ref name="unep">{{cite web |url = http://www.unep.org/vitalforest/Report/VFG-01-Forest-definition-and-extent.pdf |archive-url=https://web.archive.org/web/20100726140947/http://www.unep.org/vitalforest/Report/VFG-01-Forest-definition-and-extent.pdf |url-status=dead |archive-date=26 July 2010 |title=Forest definition and extent |date=27 January 2010 |publisher=United Nations Environment Programme |access-date=16 November 2014}}</ref> The United Nations' [[Food and Agriculture Organization]] (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a [[Canopy (biology)|canopy]] cover of more than 10 percent, or trees able to reach these thresholds ''[[in situ]]''. It does not include land that is predominantly under agricultural or urban use."<ref>{{Cite book|url=http://www.fao.org/3/I8661EN/i8661en.pdf |archive-url=https://web.archive.org/web/20190809045851/http://www.fao.org/3/I8661EN/i8661en.pdf |archive-date=9 August 2019 |url-status=live |title=Global Forest Resources Assessment 2020 – Terms and definitions |publisher=[[Food and Agriculture Organization]] |year=2018 |location=Rome}}</ref> Using this definition, ''[[Global Forest Resources Assessment (FRA)|Global Forest Resources Assessment 2020]]'' found that forests covered {{convert|4.06|e9ha|e9acre e6sqkm e6sqmi|abbr=off}}, or approximately 31 percent of the world's land area in 2020.<ref>{{Cite book |url=https://doi.org/10.4060/ca8985en |title=The State of the World's Forests 2020. In brief – Forests, biodiversity and people |publisher=[[Food and Agriculture Organization|FAO]] & UNEP |year=2020 |isbn=978-92-5-132707-4 |location=Rome |doi=10.4060/ca8985en |s2cid=241416114}}</ref>

Forests are the largest [[Terrestrial ecosystem|terrestrial ecosystems]] of [[Earth]] by area, and are found around the globe.<ref name=yude>{{cite journal |title=The Structure, Distribution, and Biomass of the World's Forests |first1=Yude |last1=Pan |first2=Richard A. |last2=Birdsey |first3=Oliver L. |last3=Phillips |first4=Robert B. |last4=Jackson |journal=Annu. Rev. Ecol. Evol. Syst. |year=2013 |volume=44 |issue=1 |pages=593–62 |url=http://www.nrs.fs.fed.us/pubs/jrnl/2013/nrs_2013_pan_001.pdf |doi=10.1146/annurev-ecolsys-110512-135914 |bibcode=2013AREES..44..593P |url-status=live |archive-url=https://web.archive.org/web/20160807012240/http://www.nrs.fs.fed.us/pubs/jrnl/2013/nrs_2013_pan_001.pdf |archive-date=7 August 2016}}</ref> 45 percent of forest land is in the [[Tropical forest|tropical latitudes]]. The next largest share of forests are found in [[subarctic climate]]s, followed by [[Temperate rainforest|temperate]], and [[subtropic]]al zones.<ref name="auto">{{Cite book |url=https://doi.org/10.4060/ca8985en |title=The State of the World's Forests 2020. In brief – Forests, biodiversity and people |publisher=[[Food and Agriculture Organization|FAO]] & UNEP |year=2020 |isbn=978-92-5-132707-4 |location=Rome, Italy |doi=10.4060/ca8985en |s2cid=241416114}}</ref>

Forests account for 75% of the [[gross primary production]] of the Earth's [[biosphere]], and contain 80% of the Earth's plant [[biomass]]. [[Primary production#Gross primary production and net primary production|Net primary production]] is estimated at 21.9 [[gigatonne]]s of biomass per year for [[tropical forest]]s, 8.1 for [[temperate forest]]s, and 2.6 for [[boreal forest]]s.<ref name="yude" />

Forests form distinctly different [[biome]]s at different latitudes and elevations, and with different precipitation and [[evapotranspiration]] rates.<ref>{{Cite book|last=Holdridge |first=L.R. |url=http://reddcr.go.cr/sites/default/files/centro-de-documentacion/holdridge_1966_-_life_zone_ecology.pdf |archive-url=https://web.archive.org/web/20161005035018/http://reddcr.go.cr/sites/default/files/centro-de-documentacion/holdridge_1966_-_life_zone_ecology.pdf |archive-date=5 October 2016 |url-status=live |title=Life zone ecology |publisher=Tropical Science Center |location=San Jose, Costa Rica}}</ref> These biomes include boreal forests in subarctic climates, [[tropical and subtropical moist broadleaf forests|tropical moist forests]] and [[tropical and subtropical dry broadleaf forests|tropical dry forests]] around the [[tropics|Equator]], and [[temperate forest]]s at the [[middle latitudes]]. Forests form in areas of the Earth with high rainfall, while drier conditions produce a transition to [[savanna]]. However, in areas with intermediate rainfall levels, forest transitions to savanna rapidly when the percentage of land that is covered by trees drops below 40 to 45 percent.<ref>{{cite web |last1=Edwards |first1=Lin |title=Forest and savanna can switch quickly |url=https://phys.org/news/2011-10-forest-savanna-quickly.html |website=Phys.org}}</ref> Research conducted in the [[Amazon rainforest]] shows that trees can alter rainfall rates across a region, releasing water from their leaves in anticipation of seasonal rains to trigger the wet season early. Because of this, seasonal rainfall in the Amazon begins two to three months earlier than the climate would otherwise allow.<ref>{{cite web |last1=Rasmussen |first1=Carol |title=New study shows the Amazon makes its own rainy season |url=https://climate.nasa.gov/news/2608/new-study-shows-the-amazon-makes-its-own-rainy-season/ |website=nasa.gov|date=17 July 2017 }}</ref><ref>{{cite web |last1=Loomis |first1=Ilima |title=Trees in the Amazon make their own rain |url=https://www.science.org/content/article/trees-amazon-make-their-own-rain}}</ref> [[Deforestation]] in the Amazon and anthropogenic [[climate change]] hold the potential to interfere with this process, causing the forest to pass a threshold where it transitions into savanna.<ref>{{cite web |last1=Kimbrough |first1=Liz |title=More droughts are coming, and the Amazon can't keep up: Study |url=https://news.mongabay.com/2022/09/more-droughts-are-coming-and-the-amazon-isnt-ready-study/ |website=Mongabay|date=16 September 2022 }}</ref>

Deforestation threatens many forest ecosystems. Deforestation occurs when humans remove trees from a forested area by cutting or burning, either to harvest [[timber]] or to make way for farming. Most deforestation today occurs in tropical forests. The vast majority of this deforestation is because of the production of four commodities: [[wood]], [[beef]], [[soy]], and [[palm oil]].<ref>{{cite web |last1=Derouin |first1=Sarah |title=Deforestation: facts, causes & effects |url=https://www.livescience.com/27692-deforestation.html |website=Live Science|date=6 January 2022 }}</ref> Over the past 2,000 years, the area of land covered by forest in [[Europe]] has been reduced from 80% to 34%. Large areas of forest have also been cleared in [[China]] and in the eastern [[United States]],<ref>{{cite web |title=Deforestation |url=https://education.nationalgeographic.org/resource/deforestation/ |publisher=National Geographic}}</ref> in which only 0.1% of land was left undisturbed.<ref>{{cite web |title=Eastern Deciduous Forest (U.S. National Park Service) |url=https://www.nps.gov/im/ncrn/eastern-deciduous-forest.htm |website=nps.gov}}</ref> Almost half of Earth's forest area (49 percent) is relatively intact, while 9 percent is found in fragments with little or no connectivity. Tropical rainforests and boreal coniferous forests are the least fragmented, whereas subtropical dry forests and temperate oceanic forests are among the most fragmented. Roughly 80 percent of the world's forest area is found in patches larger than {{convert|1|e6ha|abbr=off}}. The remaining 20 percent is located in more than 34 million patches around the world – the vast majority less than {{convert|1000|ha}} in size.<ref name="auto"/>

Human society and forests can affect one another positively or negatively.<ref>{{cite book |chapter=Global Societies and Forest Legacies Creating Today's Forest Landscapes |pages=30–59 |title=Forests and Society: Sustainability and Life Cycles of Forests in Human Landscapes |editor-last=Vogt |editor-first=Kristina A |year=2007 |publisher=CABI |isbn=978-1-84593-098-1}}</ref> Forests provide [[ecosystem services]] to humans and serve as tourist attractions. Forests can also affect people's health.<!--Specific statements supported by refs in "Relationship to human society" section--> Human activities, including unsustainable use of forest resources, can negatively affect forest ecosystems.<!--See same section for refs--><ref>{{Cite web|date=7 February 2019 |title=Deforestation and Its Effect on the Planet |url=https://www.nationalgeographic.com/environment/article/deforestation |archive-url=https://web.archive.org/web/20210219023929/https://www.nationalgeographic.com/environment/article/deforestation |url-status=dead |archive-date=19 February 2021 |access-date=21 July 2021 |website=[[National Geographic]] Environment |language=en}}</ref>

== Definitions ==
[[File:Gate in the forest - geograph.org.uk - 1726119.jpg|thumb|Forest in the [[Scottish Highlands]] ]]
Although the word ''forest'' is commonly used, there is no universally recognised precise definition, with more than 800 definitions of forest used around the world.<ref name="unep"/> Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future,<ref name="ap862">{{cite web |url=http://www.fao.org/docrep/017/ap862e/ap862e00.pdf |title=Forest Resources Assessment Working Paper 180 |first1=Kenneth |last1=MacDicken |publisher=[[Food and Agriculture Organization]] of the United Nations Forestry Department |location=Rome |date=15 March 2013 |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20150924131113/http://www.fao.org/docrep/017/ap862e/ap862e00.pdf |archive-date=24 September 2015}}</ref> or was legally designated as a forest regardless of vegetation type.<ref name="ipcc">{{cite web |url=http://www.ipcc.ch/ipccreports/sres/land_use/index.php?idp=46|title=Land Use, Land-Use Change and Forestry |editor1-first=Robert T. |editor1-last=Watson |editor2-first=David J. |editor2-last=Verardo |editor3-first=Ian R. |editor3-last=Noble |editor4-first=Bert |editor4-last=Bolin |editor5-first=N.H. |editor5-last=Ravindranath |editor6-first=David J. |editor6-last=Dokken |publisher=[[Intergovernmental Panel on Climate Change]] |year=2000 |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20141129020202/http://www.ipcc.ch/ipccreports/sres/land_use/index.php?idp=46 |archive-date=29 November 2014}}</ref><ref>{{cite web |url=http://www.forestfacts.org/l_3/forests_1.htm#1p1 |title=Facts on Forests and Forestry |first1=Nicholas |last1=Menzies |first2=Elisabeth |last2=Grinspoon |publisher= ForestFacts.org, a subsidiary of GreenFacts.org |date=22 October 2007 |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20150508030720/http://www.forestfacts.org/l_3/forests_1.htm#1p1 |archive-date=8 May 2015}}</ref>

There are three broad categories of definitions of forest in use: administrative, [[land use]], and [[land cover]].<ref name="ipcc"/> Administrative definitions are legal designations, and may not reflect the type of vegetation that grows upon the land; an area can be legally designated "forest" even if no trees grow on it.<ref name="ipcc"/> Land-use definitions are based on the primary purpose the land is used for. Under a land-use definition, any area used primarily for harvesting timber, including areas that have been cleared by harvesting, disease, fire, or for the construction of roads and infrastructure, are still defined as forests, even if they contain no trees. Land-cover definitions define forests based upon the density of trees, area of [[tree canopy]] cover, or area of the land occupied by the cross-section of tree trunks ([[basal area]]) meeting a particular threshold.<ref name="ipcc"/> This type of definition depends upon the presence of trees sufficient to meet the threshold, or at least of immature trees that are expected to meet the threshold once they mature.<ref name="ipcc"/>

Under land-cover definitions, there is considerable variation on where the cutoff points are between a forest, [[woodland]], and [[savanna]]. Under some definitions, to be considered a forest requires very high levels of tree canopy cover, from 60% to 100%,<ref>{{cite web |url=http://www.museum.state.il.us/muslink/forest/htmls/intro_def.html |title=Introduction: Definition of a Forest |publisher=MuseumLink Illinois |access-date=16 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20141029231145/http://www.museum.state.il.us/muslink/forest/htmls/intro_def.html |archive-date=29 October 2014}}</ref> which excludes woodlands and savannas, which have a lower [[crown closure|canopy cover]]. Other definitions consider savannas to be a type of forest, and include all areas with tree canopies over 10%.<ref name="ap862"/>

Some areas covered with trees are legally defined as agricultural areas, for example [[Norway spruce]] plantations, under Austrian forest law, when the trees are being grown as Christmas trees and are below a certain height.

== Etymology ==
[[File:Niepolomice oli 2013251.jpg|thumb|right|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.<ref>{{cite web |url=http://earthobservatory.nasa.gov/IOTD/view.php?id=82464 |title=A Polish Royal Forest |publisher=[[NASA Earth Observatory]] |date=29 November 2013 |url-status=live |archive-url=https://web.archive.org/web/20140104205531/http://earthobservatory.nasa.gov/IOTD/view.php?id=82464 |archive-date=4 January 2014}}</ref>]]

The word ''[[Wikt:forest|forest]]'' derives from the [[Old French]] ''forest'' (also ''forès''), denoting "forest, vast expanse covered by trees"; ''forest'' was first introduced into English as the word denoting wild land set aside for hunting<ref>{{cite web |url=http://www.broadland.gov.uk/PDF/Broadsheet_093_-_April_2011_%283%29.pdf |title=Broadsheet: The News Letter for Broadland Tree Wardens |volume=Issue 093 |date=April 2011 |access-date=16 November 2014 |url-status=dead |archive-url=https://web.archive.org/web/20141129030802/http://www.broadland.gov.uk/PDF/Broadsheet_093_-_April_2011_%283%29.pdf |archive-date=29 November 2014}}</ref> without necessarily having trees on the land.<ref>{{cite book|first=E. |last=Ritter |editor-first=D. |editor-last=Dauksta |url=https://books.google.com/books?id=XxB-HZlbTe0C&q=etymology+of+forest&pg=PA180 |title=New Perspectives on People and Forests |volume=9 |series=World Forests |publisher=Springer |year=2011 |isbn=978-94-007-1149-5}}</ref> Possibly a borrowing, probably via [[Old Frankish|Frankish]] or [[Old High German]], of the [[Medieval Latin]] {{Lang|la-x-medieval|foresta}}, denoting "open wood", [[Carolingian]] scribes first used ''foresta'' in the [[Carolingian Empire#Capitularies|capitularies]] of [[Charlemagne]], specifically to denote the royal hunting grounds of the king. The word was not endemic to the [[Romance languages]], e.g., native words for ''forest'' in the Romance languages derived from the [[Latin]] ''silva'', which denoted "forest" and "[[Woodland|wood(land)]]" ([[cf.]] the English ''sylva'' and ''sylvan''; the Italian, Spanish, and Portuguese ''selva''; the Romanian ''silvă''; the Old French ''selve''). Cognates of forest in Romance languages—e.g., the Italian ''foresta'', Spanish and Portuguese ''floresta'', etc.—are all ultimately derivations of the French word.

[[File:The forest near Blatets, Vinitsa.JPG|thumb|A forest near [[Vinica, North Macedonia|Vinitsa]], [[North Macedonia]] ]]

The precise origin of Medieval Latin {{Lang|la-x-medieval|foresta}} is obscure. Some authorities claim the word derives from the [[Late Latin]] phrase ''forestam silvam'', denoting "the outer wood"; others claim the word is a Latinisation of the Frankish *''forhist'', denoting "forest, wooded country", and was assimilated to ''forestam silvam'', pursuant to the common practice of Frankish scribes. The Old High German ''forst'' denoting "forest"; [[Middle Low German]] ''vorst'' denoting "forest"; [[Old English]] ''fyrhþ'' denoting "forest, woodland, game preserve, hunting ground" (English ''[[wikt:frith|frith]]''); and [[Old Norse]] ''fýri'', denoting "[[coniferous forest]]"; all of which derive from the [[Proto-Germanic]] *''furhísa-'', *''furhíþija-'', denoting "a [[Fir wood|fir-wood]], ''coniferous'' forest", from the [[Proto-Indo-European language|Proto-Indo-European]] *''perk<sup>w</sup>u-'', denoting "a ''coniferous'' or [[Mountain forests|mountain forest]], wooded height" all attest to the Frankish *''forhist''.

Uses of ''forest'' in English to denote any uninhabited and unenclosed area are presently considered archaic.<ref name="oed" /> The [[Norman conquest of England|Norman rulers of England]] introduced the word as a legal term, as seen in Latin texts such as [[Magna Carta]], to denote uncultivated land that was legally designated for hunting by feudal [[nobility]] (see [[Royal Forest|royal forest]]).<ref name="oed"/><ref>{{Cite book |title=The American Heritage Dictionary of the English Language |publisher=[[Houghton Mifflin]] Company |location=Boston |year=1996 |edition=3 |chapter=forest, noun |isbn=978-0-395-44895-3}}</ref>

These hunting forests did not necessarily contain any trees. Because that often included significant areas of woodland, "forest" eventually came to connote woodland in general, regardless of tree density.{{Citation needed|date=May 2009}} By the beginning of the fourteenth century, English texts used the word in all three of its senses: common, legal, and archaic.<ref name="oed">{{cite web |url=http://www.oed.com/ |title=forest, noun |website=[[Oxford English Dictionary]] online edition |publisher=[[Oxford University Press]] |access-date=22 May 2009 |url-status=live |archive-url=https://web.archive.org/web/20080111125659/http://www.oed.com/ |archive-date=11 January 2008}}</ref> Other English words used to denote "an area with a high density of trees" are ''firth'', ''frith'', ''holt'', ''weald'', ''wold'', ''wood'', and ''woodland''. Unlike ''forest'', these are all derived from Old English and were not borrowed from another language. Some present classifications reserve ''woodland'' for denoting a locale with more open space between trees, and distinguish kinds of woodlands as ''open forests'' and ''closed forests'', premised on their [[crown cover]]s.<ref>{{cite web |url=http://www.daff.gov.au/brs/forest-veg/nfi/forest-info/what-is |website=Australian Government/Department of Agriculture, Fisheries, and Forestry/Rural Areas |title=What is a Forest? |date=28 March 2007 |access-date=25 November 2010 |archive-url=https://web.archive.org/web/20091009061955/http://www.daff.gov.au/brs/forest-veg/nfi/forest-info/what-is |archive-date=9 October 2009}}</ref> Finally, ''sylva'' (plural ''sylvae'' or, less classically, ''sylvas'') is a peculiar English spelling of the Latin ''silva'', denoting a "woodland", and has precedent in English, including its plural forms. While its use as a [[synonym]] of ''forest'', and as a [[Latin]]ate word denoting a woodland, may be admitted; in a specific technical sense it is restricted to denoting the ''species'' of trees that comprise the woodlands of a region, as in its sense in the subject of [[silviculture]].<ref>Confer John Evelyn, FRS, ''[[Sylva, or A Discourse of Forest-Trees and the Propagation of Timber|Sylva, or A Discourse of Forest-Trees and the Propagation of Timber in His Majesty's Dominions]]'' (1664); and the title of and use ''passim'' in Edward Step, FLS, ''Wayside and Woodland Trees: A Pocket Guide to the British Sylva'' (Frederick Warne and Company Limited, London and New York, [many editions]).</ref> The resorting to ''sylva'' in English indicates more precisely the denotation that the use of ''forest'' intends.

== Evolutionary history ==
The first known forests on Earth arose in the [[Middle Devonian]] (approximately 390 [[Mya (unit)|million years ago]]), with the evolution of [[cladoxylopsid]] plants like ''[[Calamophyton]]''.<ref>{{cite journal|author=Davies, Neil S., McMahon, William J. and Berry, Christopher M.|year=2024|url=https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|title=Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England|journal=Journal of the Geological Society|volume=181 |issue=4 |doi=10.1144/jgs2023-204|bibcode=2024JGSoc.181..204D |archive-url=https://web.archive.org/web/20240309154116/https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|archive-date=2024-03-09|url-status=live}}</ref> Appeared in the [[Late Devonian]], ''[[Archaeopteris]]'' was both tree-like and [[fern]]-like plant, growing to {{convert|20|m|ft}} in height or more.<ref name=Devonian>{{cite web|url=http://www.devoniantimes.org/opportunity/forests.html |title=The First Forests |website=Devonian Times |access-date=9 March 2024 |url-status=dead |archive-url=https://web.archive.org/web/20160510190820/http://www.devoniantimes.org/opportunity/forests.html |archive-date=10 May 2016}}</ref> It quickly spread throughout the world, from the equator to subpolar latitudes.<ref name=Devonian/> It is the first species known to cast shade due to its [[Frond|fronds]] and forming soil from its roots. ''Archaeopteris'' was [[deciduous]], dropping its fronds onto the forest floor, the shade, soil, and forest [[Plant litter|duff]] from the dropped fronds creating the early forest.<ref name=Devonian/> The shed organic matter altered the freshwater environment, slowing its flow and providing food. This promoted freshwater fish.<ref name=Devonian/>

== Ecology<span class="anchor" id="Distribution"></span> ==
{{Main|Forest ecology}}
[[File:Hellyer Gorge, Tasmania.jpg|thumb|[[Temperate rainforest]] in Tasmania's [[Hellyer Gorge]]]]

Forests account for 75% of the [[gross primary productivity]] of the Earth's [[biosphere]], and contain 80% of the Earth's plant biomass.<ref name="yude" /> [[Biomass (ecology)|Biomass]] per unit area is high compared to other vegetation communities. Much of this biomass occurs below ground in the root systems and as partially decomposed plant [[detritus]]. The woody component of a forest contains [[lignin]], which is relatively slow to [[decompose]] compared with other organic materials such as [[cellulose]] or carbohydrate. The world's forests contain about 606 gigatonnes of living biomass (above- and below-ground) and 59 gigatonnes of dead wood. The total biomass has decreased slightly since 1990, but biomass per unit area has increased.<ref name=":0">{{Cite book |title=Global Forest Resources Assessment 2020 – Key findings |publisher=[[Food and Agriculture Organization]] |year=2020 |isbn=978-92-5-132581-0 |location=Rome |doi=10.4060/ca8753en |s2cid=130116768}}</ref>

Forest ecosystems broadly differ based on [[climate]]; latitudes 10° north and south of the [[equator]] are mostly covered in [[tropical rainforest]], and the latitudes between [[53rd parallel north|53°N]] and [[67th parallel north|67°N]] have [[boreal forest]]. As a general rule, forests dominated by [[angiosperms]] (''broadleaf forests'') are more species-rich than those dominated by [[gymnosperms]] (''conifer'', ''montane'', or ''needleleaf forests''), although exceptions exist. The trees that form the principal structural and defining component of a forest may be of a great variety of species (as in [[tropical rainforest]]s and [[temperate deciduous forest]]s), or relatively few species over large areas (e.g., [[taiga]] and arid [[montane]] coniferous forests). The biodiversity of forests also encompasses [[shrubs]], herbaceous plants, [[moss]]es, [[fern]]s, [[lichen]]s, [[fungi]], and a variety of [[animal]]s.

Trees rising up to {{convert|35|meters|ft}} in height add a vertical dimension to the area of land that can support plant and animal species, opening up numerous [[ecological niche]]s for [[arboreal locomotion|arboreal]] animal species, [[epiphyte]]s, and various species that thrive under the regulated microclimate created under the canopy.<ref>{{cite web |last1=Cannon |first1=Charles |last2=Schlesinger |first2=William H. |title=Arboreal Dimensions of Biodiversity |date=2 August 2021 |url=https://blogs.nicholas.duke.edu/citizenscientist/arboreal-dimensions-of-biodiversity/}}</ref> Forests have intricate three-dimensional structures that increase in complexity with lower levels of disturbance and greater variety of tree species.<ref>{{cite web |title=Forests of the world in 3-D: Research team analyses complexity of forest structure |url=https://phys.org/news/2021-02-forests-world-d-team-analyses.html |website=phys.org |publisher=University of Gottingen}}</ref>

The biodiversity of forests varies considerably according to factors such as forest type, geography, climate, and soils – in addition to human use.<ref name=":1">{{Cite book |url=https://doi.org/10.4060/ca8985en |title=The State of the World's Forests 2020. Forests, biodiversity and people – In brief |publisher=[[Food and Agriculture Organization|FAO]] & UNEP |year=2020 |isbn=978-92-5-132707-4 |location=Rome |doi=10.4060/ca8985en |s2cid=241416114}}</ref> Most forest habitats in temperate regions support relatively few animal and plant species, and species that tend to have large geographical distributions, while the montane forests of Africa, South America, Southeast Asia, and lowland forests of Australia, coastal Brazil, the Caribbean islands, Central America, and insular Southeast Asia have many species with small geographical distributions.<ref name=":1" /> Areas with dense human populations and intense agricultural land use, such as Europe, parts of Bangladesh, China, India, and North America, are less intact in terms of their biodiversity.<ref name=":1" /> Northern Africa, southern Australia, coastal Brazil, Madagascar, and South Africa are also identified as areas with striking losses in biodiversity intactness.<ref name=":1" />

=== Components ===
[[File:Brussels Zonienwoud.jpg|thumb|Even, dense [[Old growth forest|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]].]]

A forest consists of many components that can be broadly divided into two categories: biotic (living) and abiotic (non-living). The living parts include [[tree]]s, [[shrub]]s, [[vine]]s, [[grass]]es and other herbaceous (non-woody) plants, [[moss]]es, [[algae]], [[fungi]], [[insect]]s, [[mammal]]s, [[bird]]s, [[reptile]]s, [[amphibian]]s, and microorganisms living on the plants and animals and in the soil, connected by [[mycorrhizal network]]s.<ref>{{cite news|url=https://www.npr.org/sections/health-shots/2021/05/04/993430007/trees-talk-to-each-other-mother-tree-ecologist-hears-lessons-for-people-too|title=Trees Talk To Each Other. 'Mother Tree' Ecologist Hears Lessons For People, Too|date=4 May 2021|first=Dave|last=Davies|publisher=NPR|work=Fresh Air}}</ref>

===Layers===
[[File:Spiny Forest Ifaty Madagascar.jpg|thumb|Spiny forest at Ifaty, [[Madagascar]], featuring various ''[[Adansonia]]'' (baobab) species, ''[[Alluaudia procera]]'' (Madagascar ocotillo) and other vegetation]]

The main layers of all forest types are the [[forest floor]], the understory, and the canopy. The emergent layer, above the canopy, exists in tropical rainforests. Each layer has a different set of plants and animals, depending upon the availability of sunlight, moisture, and food.
* The '''Forest floor''' is covered in dead plant material such as fallen leaves and decomposing logs, which [[detritivores]] break down into new soil. The layer of decaying leaves that covers the soil is necessary for many insects to overwinter and for amphibians, birds, and other animals to shelter and forage for food. [[Leaf litter]] also keeps the soil moist, stops erosion, and protects roots against extreme heat and cold.<ref>{{cite web |last1=Franklin |first1=Brooke |title=This Fall, Leave the Leaves! |url=https://www.usda.gov/about-usda/news/blog/fall-leave-leaves |website=usda.gov}}</ref> The [[Fungi|fungal]] [[mycelium]] that helps form the [[mycorrhizal network]] transmits nutrients from decaying material to trees and other plants. The [[forest floor]] supports a variety of plants, ferns, grasses, and tree seedlings, as well as animals such as [[ants]], [[amphibian]]s, [[spider]]s, and [[millipede]]s. 
* '''Understory''' is made up of bushes, shrubs, and young trees that are adapted to living in the shade of the canopy.
* '''Canopy''' is formed by the mass of intertwined branches, twigs, and leaves of mature trees. The crowns of the dominant trees receive most of the sunlight. This is the most productive part of the trees, where maximum food is produced. The canopy forms a shady, protective "umbrella" over the rest of the forest.
* '''Emergent layer''' exists in a tropical rain forest and is composed of a few scattered trees that tower over the canopy.<ref>{{Cite book|title = The Living World|publisher = D.A.V. College Managing Committee}}</ref>

In botany and countries like Germany and Poland, a different classification of forest vegetation is often used: tree, shrub, herb, and moss layers (see [[stratification (vegetation)]]).

=== Types ===
[[File:La foresta sopra la vista del lago di Ridracoli.jpg|thumb|[[Foreste Casentinesi, Monte Falterona, Campigna National Park|Casentinesi Forests]], Italy]]

Forests are classified differently and to different degrees of specificity. One such classification is in terms of the [[biome]]s in which they exist, combined with leaf longevity of the dominant species (whether they are [[evergreen]] or [[deciduous]]). Another distinction is whether the forests are composed predominantly of broadleaf trees, [[conifer]]ous (needle-leaved) trees, or mixed.
* [[Boreal forest]]s occupy the [[subarctic]] zone and are generally evergreen and coniferous.
* [[Temperate]] zones support both broadleaf deciduous forests (e.g., [[Temperate broadleaf and mixed forests|temperate deciduous forest]]) and evergreen coniferous forests (e.g., [[temperate coniferous forests]] and [[temperate rainforest]]s). Warm temperate zones support broadleaf evergreen forests, including [[laurel forest]]s.
* Tropical and [[subtropical]] forests include [[Tropical and subtropical moist broadleaf forests|tropical and subtropical moist forests]], [[Tropical and subtropical dry broadleaf forests|tropical and subtropical dry forests]], and [[tropical and subtropical coniferous forests]].
* Forests are classified according to physiognomy based on their overall physical structure or [[Ecological succession|developmental stage]] (e.g. [[old growth]] vs. [[Secondary forest|second growth]]).
* Forests can also be classified more specifically based on the climate and the dominant tree species present, resulting in numerous different forest types (e.g., [[Ponderosa pine]]/[[Douglas fir]] forest).

The number of trees in the world, according to a 2015 estimate, is 3 trillion, of which 1.4 trillion are in the tropics or sub-tropics, 0.6 trillion in the temperate zones, and 0.7 trillion in the coniferous boreal forests. The 2015 estimate is about eight times higher than previous estimates, and is based on tree densities [[Forest inventory|measured]] on over 400,000 plots. It remains subject to a wide margin of error, not least because the samples are mainly from Europe and North America.<ref>{{cite web |last1=Amos |first1=Jonathan |title=Earth's trees number 'three trillion' |url=https://www.bbc.co.uk/news/science-environment-34134366 |publisher=BBC |access-date=3 September 2015 |date=3 September 2015 |url-status=live |archive-url=https://web.archive.org/web/20150903082255/http://www.bbc.co.uk/news/science-environment-34134366 |archive-date=3 September 2015}}</ref>

Forests can also be classified according to the amount of human alteration. [[Old-growth forest]] contains mainly natural patterns of biodiversity in established [[seral]] patterns, and they contain mainly species native to the region and habitat. In contrast, [[secondary forest]] is forest regrowing following timber harvest and may contain species originally from other regions or habitats.<ref name="Chazdon">{{cite journal|last=Chazdon|first=Robin L.|author-link=Robin Chazdon|year=2008|title=Beyond deforestation: restoring forests and ecosystem services on degraded lands|url=http://lerf.eco.br/img/publicacoes/2008_2411%20Beyond%20Deforestation%20Restoring%20Forests%20and%20Ecosystem%20Services%20on%20Degraded%20Lands.pdf|url-status=live|journal=Science|volume=320|issue=5882|pages=1458–60|bibcode=2008Sci...320.1458C|doi=10.1126/science.1155365|pmid=18556551|archive-url=https://web.archive.org/web/20161021132745/http://lerf.eco.br/img/publicacoes/2008_2411%20Beyond%20Deforestation%20Restoring%20Forests%20and%20Ecosystem%20Services%20on%20Degraded%20Lands.pdf|archive-date=21 October 2016|s2cid=206511664}}</ref>

Different global forest classification systems have been proposed, but none has gained universal acceptance.<ref name=wcmc>{{cite book |last1=Jenkins |first1=Martin D. |last2=Groombridge |first2=Brian |title=World Atlas of Biodiversity: Earth's Living Resources in the 21st Century |publisher=[[World Conservation Monitoring Centre]], [[United Nations Environment Programme]] |url=https://books.google.com/books?id=_kHeAXV5-XwC&q=UNESCO+forest+and+woodland+subformations&pg=RA3-PA81 |isbn=978-0-520-23668-4 |year=2002}}</ref> [[United Nations Environment Programme|UNEP]]-[[World Conservation Monitoring Centre|WCMC]]'s forest category classification system is a simplification of other, more complex systems (e.g. [[UNESCO]]'s forest and woodland 'subformations'). This system divides the world's forests into 26 major types, which reflect climatic zones as well as the principal types of trees. These 26 major types can be reclassified into 6 broader categories: temperate needleleaf, temperate broadleaf and mixed, tropical moist, tropical dry, sparse trees and parkland, and forest plantations.<ref name=wcmc/> Each category is described in a separate section below.

==== Temperate needleleaf<span class="anchor" id="Coniferous forests"></span> ====
[[Temperate coniferous forest|Temperate needleleaf forests]] mostly occupy the higher latitudes of the [[Northern Hemisphere]], as well as some warm temperate areas, especially on nutrient-poor or otherwise unfavourable soils. These forests are composed entirely, or nearly so, of coniferous species ([[Coniferophyta]]). In the Northern Hemisphere, [[pine]]s ''Pinus'', [[spruce]]s ''Picea'', [[larch]]es ''Larix'', [[fir]]s ''Abies'', Douglas firs ''[[Pseudotsuga]]'', and hemlocks ''[[Tsuga]]'' make up the canopy; but other taxa are also important. In the [[Southern Hemisphere]], most coniferous trees (members of [[Araucariaceae]] and [[Podocarpaceae]]) occur mixed with broadleaf species, and are classed as broadleaf-and-mixed forests.<ref name=wcmc/>

====Temperate broadleaf and mixed====
[[File:Namdapha2.jpg|thumb|upright|Broadleaf forest in [[Bhutan]]]]

[[Temperate broadleaf and mixed forest]]s include a substantial component of trees of the [[Anthophyta]] group. They are generally characteristic of the warmer temperate latitudes, but extend to cool temperate ones, particularly in the southern hemisphere. They include such forest types as the mixed deciduous forests of the United States and their counterparts in China and Japan; the broadleaf evergreen [[rainforest]]s of Japan, [[Chile]], and [[Tasmania]]; the [[sclerophyllous]] forests of Australia, central Chile, the [[Mediterranean Basin|Mediterranean]], and California; and the southern beech [[Nothofagus]] forests of Chile and New Zealand.<ref name=wcmc/>

==== Tropical moist ====
There are many different types of [[Tropical and subtropical moist broadleaf forests|tropical moist forests]], with lowland evergreen broad-leaf [[tropical rainforest]]s: for example [[Várzea forest|várzea]] and [[Cantão#Natural Communities|igapó]] forests and the terra firme forests of the [[Amazon Basin]]; the [[peat swamp forest]]s; [[dipterocarp]] forests of [[Southeast Asia]]; and the [[high forest]]s of the [[Congo Basin]]. [[Seasonal tropical forest]]s, perhaps the best description for the colloquial term "[[jungle]]", typically range from the rainforest zone 10 degrees north or south of the [[equator]], to the [[Tropic of Cancer]] and [[Tropic of Capricorn]]. Forests located on mountains are also included in this category, divided largely into upper and lower [[Montane ecology|montane]] formations, on the basis of the variation of physiognomy corresponding to changes in altitude.<ref>{{cite book|first1=S|last1=Chape|first2=M|last2=Spalding|first3=M|last3=Jenkins|url=https://books.google.com/books?id=HuaGXdMTTmcC&q=Tropical+moist+forests+include+many+different+forest+types&pg=PA53|title=The world's protected areas: status, values and prospects in the 21st century|publisher=Univ de Castilla La Mancha|year=2008|isbn=978-0-520-24660-7}}</ref>

==== Tropical dry ====
[[Tropical and subtropical dry broadleaf forests|Tropical dry forests]] are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest canopy, with most trees being leafless for several months of the year. Under some conditions, such as less fertile soils or less predictable drought regimes, the proportion of evergreen species increases and the forests are characterised as "[[sclerophyllous]]". [[Deserts and xeric shrublands|Thorn forest]], a dense forest of low stature with a high frequency of thorny or spiny species, is found where drought is prolonged, and especially where grazing animals are plentiful. On very poor soils, and especially where fire or herbivory are recurrent phenomena, [[savanna]]s develop.<ref name=wcmc/>

==== Sparse trees and savanna ====
Sparse trees and [[savanna]] are forests with sparse tree-[[Canopy (biology)|canopy]] cover. They occur principally in areas of transition from forested to non-forested landscapes. The two major zones in which these [[ecosystem]]s occur are in the [[boreal ecosystem|boreal]] region and in the seasonally dry tropics. At high latitudes, north of the main zone of boreal forestland, growing conditions are not adequate to maintain a continuously closed [[forest cover]], so tree cover is both sparse and discontinuous. This vegetation is variously called open [[taiga]], open [[lichen]] woodland, and forest tundra. A savanna is a mixed [[woodland]]–[[grassland]] [[ecosystem]] characterized by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken [[herbaceous]] layer that consists primarily of grasses. Savannas maintain an open canopy despite a high tree density.<ref name=wcmc/>

==== Plantations ====
Forest plantations are generally intended for the production of timber and [[pulpwood]]. Commonly mono-specific, planted with even spacing between the trees, and intensively managed, these forests are generally important as habitat for native [[biodiversity]]. Some are managed in ways that enhance their biodiversity protection functions and can provide ecosystem services such as nutrient capital maintenance, [[Drainage basin|watershed]] and soil structure protection and carbon storage.<ref name=Chazdon/><ref name=wcmc/>

== Area ==
[[File:Forest-area-as-share-of-land-area.svg|thumb|upright=1.5|Share of land that is covered by forest|330x330px]]
The annual net loss of forest area has decreased since 1990, but the world is not on track to meet the target of the United Nations Strategic Plan for Forests to increase forest area by 3 percent by 2030.<ref name=":1" />
[[File:Share Of Forest Area In Total Land Area, Top Countries (2021).svg|thumb|330x330px|Share of forest area in total land area, top countries (2021)]]
While [[deforestation]] is taking place in some areas, new forests are being established through natural expansion or deliberate efforts in other areas. As a result, the net loss of forest area is less than the rate of deforestation; and it, too, is decreasing: from {{convert|7.8|e6ha|abbr=off}} per year in the 1990s to {{convert|4.7|e6ha|abbr=off}} per year during 2010–2020.<ref name=":1" /> In absolute terms, the global forest area decreased by {{convert|178 |e6ha|e6acre sqkm sqmi|abbr=off}} between 1990 and 2020, which is an area about the size of Libya.<ref name=":1" />

== Societal significance ==
{{Main|Forestry|Logging|Deforestation}}
[[File:Redwood M D Vaden.jpg|thumb|Redwood tree in northern California redwood forest, where many [[Sequoia sempervirens|redwood]] trees are managed for preservation and longevity, rather than being harvested for wood production]]
[[File:Verbrannter Wald, Thasos.jpg|thumb|[[Wildfire|Burned forest]] on [[Kastro, Thasos|Thasos]]]]

=== Ecosystem services ===
Forests provide a diversity of [[ecosystem services]] including:
* Converting [[carbon dioxide]] into [[oxygen]] and biomass. A full-grown tree produces about {{convert|100|kg}} of net oxygen per year.<ref>{{cite web|author=Luis Villazon|url=https://www.sciencefocus.com/planet-earth/how-many-trees-does-it-take-to-produce-oxygen-for-one-person/|title=How many trees does it take to produce oxygen for one person?|date=16 September 2015 |publisher=Science Focus|access-date=12 August 2019}}</ref>
* Acting as a [[carbon sink]]. Therefore, they are necessary to [[Climate change mitigation|mitigate climate change]].<ref name=IPCC>{{cite book |title=Global Warming of 1.5&nbsp;°C – an IPCC special report on the impacts of global warming of 1.5&nbsp;°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty Summary for Policymakers |url=http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdf |date=6 October 2018 |archive-url=https://web.archive.org/web/20181018003130/http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdf |archive-date=18 October 2018 |publisher=Intergovernmental Panel on Climate Change |page=22 |access-date=11 October 2021}}</ref>
* Aiding in regulating [[climate]]. For example, research from 2017 shows that forests induce rainfall. If the forest is cut, it can lead to [[drought]],<ref name="Rainforest-initiated wet season onset over the southern Amazon">{{cite journal |last1=S. Write |first1=Jonathon |last2=Fu |first2=Rong |last3=R. Worden |first3=John |last4=Chakraborty |first4=Sudip |last5=E. Clinton |first5=Nicholas |last6=Risi |first6=Camille |last7=Sun |first7=Ying |author7-link=Ying Sun (environmental scientist)|last8=Yin |first8=Lei |title=Rainforest-initiated wet season onset over the southern Amazon |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=114 |date=20 July 2017 |issue=Forests, Rainfall |pages=8481–86 |doi=10.1073/pnas.1621516114 |pmid=28729375 |pmc=5558997 |bibcode=2017PNAS..114.8481W |doi-access=free }}</ref> and in the tropics to [[occupational heat stress]] of outdoor workers.<ref>{{Cite news |last=Quaglia |first=Sofia |title=Deforestation making outdoor work unsafe for millions, says study |url=https://www.theguardian.com/environment/2021/dec/17/deforestation-making-outdoor-work-unsafe-for-millions-says-study |date=17 December 2021 |newspaper=The Guardian |access-date=16 February 2022}}</ref>
* Purifying [[water]].
* Mitigating natural hazards such as [[flood]]s.
* Serving as a genetic reserve.
* Serving as a source of [[lumber]] and as [[recreation]]al areas.
* Serving as a source of woodlands and trees for millions of people dependent almost entirely on forests for subsistence for their essential fuelwood, food, and fodder needs.<ref>{{Cite book|url=https://doi.org/10.4060/ca8642en|title=The State of the World's Forests 2020 – Forests, biodiversity and people|publisher=FAO & UNEP|year=2020|isbn=978-92-5-132419-6|location=Rome|doi=10.4060/ca8642en|s2cid=241858489}}</ref>

The main ecosystem services can be summarized in the next table:<ref>{{cite web |title=Primary Forests: Boreal, Temperate, Tropical |url=https://www.woodwellclimate.org/primary-forests-boreal-temperate-tropical/ |website=Woodwell Climate Research Center |date=17 December 2020 |publisher=Woodwell Climate Research Center, INTACT, Griffits University, GEOS institute, Frankfurt Zoological Society, Australian Rainforest Conservation Society |access-date=22 August 2023}}</ref>

{| class="wikitable"
|+ Main ecosystem services of the 3 main types of forest
|-
! Type of forest !! Carbon stored !! Biodiversity !! Other
|-
| Primary [[Boreal forests|Boreal Forests]] || 1,042 billion tonnes of carbon, more than currently found in the atmosphere, 2 times more than all [[Greenhouse gas emissions|human caused emissions]] since the year 1870. || Biodiversity services given by Canada forest alone are estimated as 703 billion dollars per year. Important for almost half of the [[bird]]s in North America. || Contain 60% of world [[Fresh water|surface freshwater]].
|-
| Primary [[Temperate forest|Temperate Forests]] || 119 billion tonnes (like all CO2 emitted by humans in 2005–2017) || [[Old-growth forest|Old growth forest]] has very high biodiversity. Some species link [[terrestrial ecosystem]]s to [[marine ecosystem|marine]]. || Some trees can live 1,000 years providing many services to humans. Help to protect people from [[flood]]s and [[drought]]s.
|-
| Primary [[Tropical forest|Tropical Forests]] || 471 billion tonnes (more than all CO2 emissions from fossil fuel industry from the year 1750) || Contain about two thirds of all [[species]] of terrestrial [[animal]]s and [[plant]]s. || Creates clouds, [[rainfall]].
|}

Some researchers state that forests do not only provide benefits, but can in certain cases also incur costs to humans.<ref name="R Nasi, S Wunder 2002">{{cite conference|first1=R|last1=Nasi|first2=S|last2=Wunder|first3=JJ|last3=Campos A|title=Forest ecosystem services: can they pay our way out of deforestation?|book-title=UNFF II|location=Costa Rica|date=11 March 2002|url=http://www.cifor.org/publications/pdf_files/Books/BNasi0201.pdf|url-status=live|archive-url=https://web.archive.org/web/20141204162356/http://www.cifor.org/publications/pdf_files/Books/BNasi0201.pdf|archive-date=4 December 2014}}</ref><ref>{{cite report|first1=Lucy|last1=Emerton|year=1999|title=Mount Kenya: The Economics of Community Conservation|series=Evaluating Eden Series|issue=Discussion Paper No.4|type=Community Conservation research Working Paper|publisher=University of Manchester Institute of Development Policy and Management|url=http://pubs.iied.org/pdfs/7797IIED.pdf?origin=publication_detail|url-status=live|archive-url=https://web.archive.org/web/20141204162356/http://pubs.iied.org/pdfs/7797IIED.pdf?origin=publication_detail|archive-date=4 December 2014}}</ref> Forests may impose an economic burden,<ref>{{cite report |last1=Lette |first1=Henk |last2=de Boo |first2=Henneleen |title=Economic Valuation of Forests and Nature A support tool for effective decision-making |url=http://library.wur.nl/WebQuery/wurpubs/fulltext/118103 |year=2002 |series=Theme Studies Series 6 Forests |location=Ede, The Netherlands |publisher=Forestry and Biodiversity Support Group, International Agricultural Centre (IAC), Wageningen National Reference Centre for Agriculture, Nature Management and Fisheries (EC-LNV) |access-date=16 February 2022}}</ref><ref>{{cite book|editor-first=Joshua T.|editor-last=Bishop|year=1999|title=Valuing Forests A Review of Methods and Applications in Developing Countries|publisher=Environmental Economics Programme, International Institute for Environment and Development (IIED)|location=London|url=http://siteresources.worldbank.org/INTEEI/214574-1153316226850/20486370/ValuingForestsAReviewOfMethodsAndApplicationsInDevelopingCountriesJuly1999.pdf|url-status=live|archive-url=https://web.archive.org/web/20151123100829/http://siteresources.worldbank.org/INTEEI/214574-1153316226850/20486370/ValuingForestsAReviewOfMethodsAndApplicationsInDevelopingCountriesJuly1999.pdf|archive-date=23 November 2015}}</ref> diminish the enjoyment of natural areas,<ref>{{cite journal|last1=Gray|first1=Emma F.|last2=Bond|first2=William J.|title=Will woody plant encroachment impact the visitor experience and economy of conservation areas?|journal=Koedoe|year=2013|volume=55|number=1|issn=0075-6458|doi=10.4102/koedoe.v55i1.1106|doi-access=free|hdl=11427/24844|hdl-access=free}}</ref> reduce the food-producing capacity of grazing land<ref>{{cite journal|first1=R.J.|last1=Scholes|first2=S.R.|last2=Archer|year=1997|title=Tree-Grass Interactions in Savannas|journal=Annual Review of Ecology and Systematics|volume=28|issue=1 |pages=517–44|url=http://cals.arizona.edu/research/archer/reprints/Scholes_Archer_1997_AnRevEcolSys.pdf|doi=10.1146/annurev.ecolsys.28.1.517|bibcode=1997AnRES..28..517S |url-status=dead|archive-url=https://web.archive.org/web/20141204185831/http://cals.arizona.edu/research/archer/reprints/Scholes_Archer_1997_AnRevEcolSys.pdf|archive-date=4 December 2014}}</ref> and cultivated land,<ref>{{cite book|first1=David|last1=Pimentel|first2=Marcia H.|last2=Pimentel|year=2007|title=Food, Energy, and Society|publisher=CRC Press}}</ref> reduce biodiversity,<ref>{{cite journal|first1=Zakary|last1=Ratajczak|first2=Jesse B.|last2=Nippert|first3=Scott L.|last3=Collins|year=2012|title=Woody encroachment decreases diversity across North American grasslands and savannas|journal=Ecology|volume=93|issue=4|pages=697–703|pmid=22690619|url=http://www.k-state.edu/ecophyslab/pdf%27s/Ratajczak,%20Nippert,%20and%20Collins.%202012.%20Ecology.pdf|doi=10.1890/11-1199.1|url-status=live|archive-url=https://web.archive.org/web/20150307025203/http://www.k-state.edu/ecophyslab/pdf's/Ratajczak,%20Nippert,%20and%20Collins.%202012.%20Ecology.pdf|archive-date=7 March 2015|doi-access=free|bibcode=2012Ecol...93..697R }}</ref><ref>{{cite journal|first1=Catherine L.|last1=Parr|first2=Emma F.|last2=Gray|first3=William J.|last3=Bond|year=2012|title=Cascading biodiversity and functional consequences of a global change–induced biome switch|journal=Diversity and Distributions|volume=18|issue=5|pages=493–503|url=https://www.researchgate.net/publication/259397524|doi=10.1111/j.1472-4642.2012.00882.x|s2cid=84089636|url-status=live|archive-url=https://web.archive.org/web/20170131191537/https://www.researchgate.net/profile/Emma_Gray5/publication/259397524_Cascading_biodiversity_and_functional_consequences_of_a_global_change-induced_biome_switch/links/0046352b6eb15ccff5000000.pdf|archive-date=31 January 2017|doi-access=free|bibcode=2012DivDi..18..493P }}</ref> reduce available water for humans and wildlife,<ref>{{cite conference|last1=Wilcox|first1=B.P.|last2=Kreuter|first2=U.P.|year=2003|title=Woody plant: streamflow interactions as a basis for land management decisions in drylands|conference=Proceedings VIIth International Rangelands Congress|pages=989–96}}</ref><ref>{{cite journal|last=Scott|first=D.F.|year=1999|title=Managing riparian vegetation to sustain streamflow: results of paired catchment experiments in South Africa|journal=Canadian Journal of Forest Research|volume=29|issue=7|pages=1149–51|url=http://researchspace.csir.co.za/dspace/bitstream/10204/2110/3/scott_1999.pdf|doi=10.1139/x99-042|url-status=live|archive-url=https://web.archive.org/web/20141205151715/http://researchspace.csir.co.za/dspace/bitstream/10204/2110/3/scott_1999.pdf|archive-date=5 December 2014}}</ref> harbour dangerous or destructive wildlife,<ref name="R Nasi, S Wunder 2002"/><ref>{{cite journal|last1=Davidson|first1=A|last2=Elliston|first2=L|last3=Kokic|first3=P|last4=Lawson|first4=K|year=2005|title=Native vegetation: cost of preservation in Australia|journal=Australian Commodities|volume=12|issue=3|pages=543–48|url=http://data.daff.gov.au/data/warehouse/pe_abare99001738/ac05_sept.pdf#page=101|url-status=live|archive-url=https://web.archive.org/web/20180201164407/http://data.daff.gov.au/data/warehouse/pe_abare99001738/ac05_sept.pdf#page=101|archive-date=1 February 2018}}</ref> and act as reservoirs of human and livestock disease.<ref>{{cite web | url = http://www.fao.org/docrep/009/a0789e/a0789e03.html | title = Forests and emerging infectious diseases of humans | first1 = B.A. | last1 = Wilcox | first2 = B. | last2 = Ellis | publisher = Food and Agriculture Organization of the United Nations | access-date = 16 November 2014 | url-status=live | archive-url = https://web.archive.org/web/20141129213641/http://www.fao.org/docrep/009/a0789e/a0789e03.html | archive-date = 29 November 2014}}</ref><ref>{{cite journal|title=Small rodents in the forest ecosystem as infectious disease reservoirs|journal=Acta Med Croatica|year=2003|volume=57|issue=5|pages=421–26|pmid=15011471|first=J|last=Margaletic|language=hr}}</ref>

An important consideration regarding carbon sequestration is that forests can turn from a carbon sink to a carbon source if plant diversity, density or forest area decreases, as has been observed in different tropical forests<ref>{{Cite journal |last1=Baccini |first1=A. |last2=Walker |first2=W. |last3=Carvalho |first3=L. |last4=Farina |first4=M. |last5=Sulla-Menashe |first5=D. |last6=Houghton |first6=R. A. |date=2017-10-13 |title=Tropical forests are a net carbon source based on aboveground measurements of gain and loss |url=https://www.science.org/doi/10.1126/science.aam5962 |journal=Science |language=en |volume=358 |issue=6360 |pages=230–234 |doi=10.1126/science.aam5962 |pmid=28971966 |bibcode=2017Sci...358..230B |issn=0036-8075}}</ref><ref>{{Cite journal |last1=Spawn |first1=Seth A. |last2=Sullivan |first2=Clare C. |last3=Lark |first3=Tyler J. |last4=Gibbs |first4=Holly K. |date=2020-04-06 |title=Harmonized global maps of above and belowground biomass carbon density in the year 2010 |journal=Scientific Data |language=en |volume=7 |issue=1 |pages=112 |doi=10.1038/s41597-020-0444-4 |pmid=32249772 |issn=2052-4463|pmc=7136222 |bibcode=2020NatSD...7..112S }}</ref><ref>{{Cite web |date=2017-09-28 |title=Tropical forests have flipped from sponges to sources of carbon dioxide |url=https://www.sciencenews.org/article/tropical-forests-have-flipped-sponges-sources-carbon-dioxide |access-date=2024-01-05 |language=en-US}}</ref> The typical tropical forest may become a carbon source by the 2060s.<ref>{{Cite news |last1=Harvey |first1=Fiona |author-link=Fiona Harvey |date=2020-03-04 |title=Tropical forests losing their ability to absorb carbon, study finds |url=https://www.theguardian.com/environment/2020/mar/04/tropical-forests-losing-their-ability-to-absorb-carbon-study-finds |access-date=2024-01-05 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> An assessment of European forests found early signs of carbon sink saturation, after decades of increasing strength.<ref>{{Cite journal |last1=Nabuurs |first1=Gert-Jan |last2=Lindner |first2=Marcus |last3=Verkerk |first3=Pieter J. |last4=Gunia |first4=Katja |last5=Deda |first5=Paola |last6=Michalak |first6=Roman |last7=Grassi |first7=Giacomo |date=September 2013 |title=First signs of carbon sink saturation in European forest biomass |url=https://www.nature.com/articles/nclimate1853 |journal=Nature Climate Change |language=en |volume=3 |issue=9 |pages=792–796 |doi=10.1038/nclimate1853 |bibcode=2013NatCC...3..792N |issn=1758-6798}}</ref> The [[Intergovernmental Panel on Climate Change|Intergovernmental Panel on Climate Change (IPCC)]] concluded that a combination of measures aimed at increasing forest carbon stocks, andsustainable timber offtake will generate the largest carbon sequestration benefit.<ref>{{Citation |title=Forestry |date=2007 |url=https://www.cambridge.org/core/books/climate-change-2007-mitigation-of-climate-change/forestry/252A8A6E2DAE291C4769FD9385DA26C4 |work=Climate Change 2007 - Mitigation of Climate Change: Working Group III contribution to the Fourth Assessment Report of the IPCC |pages=541–584 |editor-last=Intergovernmental Panel on Climate Change |access-date=2024-01-05 |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/CBO9780511546013.013 |isbn=978-1-107-79970-7}}</ref>

=== Forest-dependent people ===
The term forest-dependent people is used to describe any of a wide variety of livelihoods that are dependent on access to forests, products harvested from forests, or ecosystem services provided by forests, including those of Indigenous peoples dependent on forests.<ref name="auto1">{{cite journal |last1=Newton |first1=Peter |last2=Miller |first2=Daniel C. |last3=Byenkya |first3=Mugabi Augustine Ateenyi |last4=Agrawal |first4=Arun |title=Who are forest-dependent people? A taxo nomy to aid livelihood and land use decision-making in forested regions |journal=Land Use Policy |date=2016 |volume=57 |pages=388–395|doi=10.1016/j.landusepol.2016.05.032 |doi-access=free |bibcode=2016LUPol..57..388N }}</ref> In [[India]], approximately 22 percent of the population belongs to forest-dependent communities, which live in close proximity to forests and practice [[agroforestry]] as a principal part of their livelihood.<ref>{{cite web |last1=Prateek |first1=Gautam |last2=Punia |first2=Sumendera |title=India's forest-dependent communities will benefit from policies recognising their integrated agri-forestry livelihood |url=https://www.downtoearth.org.in/blog/forests/india-s-forest-dependent-communities-will-benefit-from-policies-recognising-their-integrated-agri-forestry-livelihood-86929 |website=DownToEarth|date=4 January 2023 }}</ref> People of [[Ghana]] who rely on [[timber]] and [[bushmeat]] harvested from forests and Indigenous peoples of the Amazon rainforest are also examples of forest-dependent people.<ref name="auto1"/> Though forest-dependence by more common definitions is statistically associated with poverty and [[rural]] livelihoods, elements of forest-dependence exist in communities with a wide range of characteristics. Generally, richer households derive more cash value from forest resources, whereas among poorer households, forest resources are more important for home consumption and increase community resilience.<ref>{{Cite web|url=https://www.iucn.org/news/forests/201611/understanding-human-dependence-forests-overview-iucn%E2%80%99s-efforts-and-findings-and-their-implications|title=Understanding human dependence on forests: An overview of IUCN's efforts and findings, and their implications|date=2 November 2016|website=IUCN}}</ref>

=== Indigenous peoples ===
Forests are fundamental to the culture and livelihood of indigenous people groups that live in and depend on forests,<ref>{{cite web |title=Interview: Deforestation Threatens Indonesia's Indigenous Peoples |url=https://www.hrw.org/news/2019/09/22/interview-deforestation-threatens-indonesias-indigenous-peoples |website=Human Rights Watch|date=22 September 2019 }}</ref> many of which have been removed from and denied access to the lands on which they lived as part of global [[colonialism]]. Indigenous lands contain 36% or more of intact forest worldwide, host more biodiversity, and experience less deforestation.<ref>{{cite web |last1=Cannon |first1=John |title=Indigenous lands hold 36% or more of remaining intact forest landscapes |url=https://news.mongabay.com/2020/01/indigenous-lands-hold-36-or-more-of-remaining-intact-forest-landscapes/ |website=Mongabay|date=16 January 2020 }}</ref><ref>{{cite news |last1=Carrington |first1=Damian |title=Indigenous peoples by far the best guardians of forests – UN report |url=https://www.theguardian.com/environment/2021/mar/25/indigenous-peoples-by-far-the-best-guardians-of-forests-un-report |newspaper=The Guardian|date=25 March 2021 }}</ref><ref>{{cite web |last1=Chemnick |first1=Jean |title=Amazon Deforestation Falls Where Land Is under Indigenous Control |url=https://www.scientificamerican.com/article/amazon-deforestation-falls-where-land-is-under-indigenous-control/ |website=Scientific American}}</ref> Indigenous activists have argued that degradation of forests and indigenous peoples' marginalization and land dispossession are interconnected.<ref>{{cite web |title=Indigenous Peoples Excluded from Political Power, Ejected from Lands, Faced Corporations Bent on Destroying Life-Giving Forests, Permanent Forum Told |url=https://press.un.org/en/2010/hr5021.doc.htm |website=United Nations Meetings Coverage and Press Releases}}</ref><ref>{{cite journal |last1=Doolittle |first1=Amy |title=The Politics of Indigeneity: Indigenous Strategies for Inclusion in Climate Change Negotiations |journal=Conservation & Society |date=2010 |volume=8 |issue=4|page=256 |doi=10.4103/0972-4923.78142 |hdl=10535/8315 |hdl-access=free |doi-access=free }}</ref> Other concerns among indigenous peoples include lack of Indigenous involvement in forest management and loss of knowledge related for the forest ecosystem.<ref>{{cite journal |last1=Carson |first1=Savanna L. |last2=Kentatchime |first2=Fabrice |last3=Nana |first3=Eric Djomo |last4=Njabo |first4=Kevin Y. |last5=Cole |first5=Brian L. |last6=Godwin |first6=Hilary A. |title=Indigenous Peoples' Concerns About Loss of Forest Knowledge: Implications for Forest Management |journal=Conservation & Society |date=2018 |volume=16 |issue=4}}</ref> Since 2002, the amount of land that is legally owned by or designated for indigenous peoples has broadly increased, but land acquisition in lower-income countries by multinational corporations, often with little or no consultation of indigenous peoples, has also increased.<ref>{{cite tech report | last=Savedoff | first=William | title=Competing or Complementary Strategies?: Protecting Indigenous Rights and Paying to Conserve Forests | year=2018 | jstor=resrep29743.4 | page=4–10}}</ref> Research in the Amazon rainforest suggests that indigenous methods of agroforestry form reservoirs of biodiversity.<ref>{{cite journal |last1=Sanabria |first1=Catalina |last2=Achury |first2=Rafael |title=Amazonian indigenous territories as reservoirs of biodiversity - Territorios indígenas amazónicos como reservorio de biodiversidad: The army ants of Santa Sofia (Amazonas – Colombia) |journal=Caldasia |date=2022 |volume=44 |issue=2|doi=10.15446/caldasia.v44n2.92330 |doi-access=free }}</ref> In the U.S. state of [[Wisconsin]], forests managed by indigenous people have more plant diversity, fewer invasive species, higher tree regeneration rates, and higher volume of trees.<ref>{{cite journal |last1=Waller |first1=Donald M. |last2=Reo |first2=Nicholas J. |title=First stewards: ecological outcomes of forest and wildlife stewardship by indigenous peoples of Wisconsin, USA |journal=Ecology and Society |date=2018 |volume=23 |issue=1|doi=10.5751/ES-09865-230145 |doi-access=free }}</ref>

== Management ==
{{Main|Forest management|}}
[[File:World Production Of Selected Forest Products.svg|thumb|World production of selected forest products]]
[[Forest management]] has changed considerably over the last few centuries, with rapid changes from the 1980s onward, culminating in a practice now referred to as ''sustainable forest management''. Forest ecologists concentrate on forest patterns and processes, usually with the aim of elucidating cause-and-effect relationships. [[Forester]]s who practice sustainable forest management focus on the integration of ecological, social, and economic values, often in [[Stakeholder engagement|consultation with local communities and other stakeholders]].
[[File:Checkerboard forest in Idaho.jpg|alt=Priest River winds through mountains with a checkerboard design of trees to its east|thumb|[[Priest River (Idaho)|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]]

Humans have generally decreased the amount of forest worldwide. Anthropogenic factors that can affect forests include logging, [[urban sprawl]], human-caused [[forest fire]]s, [[acid rain]], [[invasive species]], and the [[slash and burn]] practices of swidden agriculture or [[shifting cultivation]]. The loss and re-growth of forests lead to a distinction between two broad types of forest: primary or [[old-growth forest]] and [[secondary forest]]. There are also many natural factors that can cause changes in forests over time, including [[forest fires]], [[Forest pathology#Animals|insects]], [[Forest pathology|diseases]], weather, competition between species, etc. In 1997, the [[World Resources Institute]] recorded that only 20% of the world's original forests remained in large intact tracts of undisturbed forest.<ref>World Resources Institute (1997). [http://www.intactforests.org/pdf.publications/Last.Frontier.Forests.1997.pdf The Last Frontier Forests: Ecosystems and Economies on the Edge] {{webarchive|url=https://web.archive.org/web/20170813235644/http://www.intactforests.org/pdf.publications/Last.Frontier.Forests.1997.pdf |date=13 August 2017 }}.</ref> More than 75% of these intact forests lie in three countries: the boreal forests of Russia and Canada, and the rainforest of Brazil.

According to [[Food and Agriculture Organization]]'s (FAO) ''Global Forest Resources Assessment 2020'', an estimated {{convert|420|e6ha|e9acre|abbr=off}} of forest have been lost worldwide through deforestation since 1990, but the rate of [[forest loss]] has declined substantially. In the most recent five-year period (2015–2020), the annual rate of deforestation was estimated at {{convert|10|e6ha|abbr=off}}, down from {{convert|12|e6ha|abbr=off}} annually in 2010–2015.<ref name=":0" />

=== The forest transition ===
The transition of a region from forest loss to net gain in forested land is referred to as the forest transition. This change occurs through a few main pathways, including increase in commercial tree plantations, adoption of [[agroforestry]] techniques by small farmers, or spontaneous regeneration when former agricultural land is abandoned. It can be motivated by the economic benefits of forests, the ecosystem services forests provide, or cultural changes where people increasingly appreciate forests for their spiritual, aesthetic, or otherwise intrinsic value.<ref>{{cite journal |last1=Wilson |first1=Sarah Jane |last2=Schelhas |first2=John |last3=Grau |first3=Ricardo |last4=Nanni |first4=A Sofia |last5=Sloan |first5=Sean |title=Forest ecosystem-service transitions: the ecological dimensions of the forest transition |journal=Ecology and Society |date=2017 |volume=22 |issue=4|doi=10.5751/ES-09615-220438 |hdl=11336/67453 |hdl-access=free }}</ref> According to the [[Special Report on Global Warming of 1.5&nbsp;°C]] of the [[Intergovernmental Panel on Climate Change]], to avoid temperature rise by more than 1.5 degrees above pre-industrial levels, there will need to be an increase in global forest cover equal to the land area of Canada ({{convert|10|e6sqkm|e6sqmi|abbr=off}}) by 2050.<ref name=IPCC/>

China instituted a ban on logging, beginning in 1998, due to the erosion and flooding that it caused.<ref>{{cite news |title=Ban on Logging Saves Forests |url=http://english.people.com.cn/english/200110/25/eng20011025_83160.html |date=25 October 2001 |url-status=live |archive-url=https://web.archive.org/web/20110629191535/http://english.people.com.cn/english/200110/25/eng20011025_83160.html |archive-date=29 June 2011 |newspaper=[[People's Daily]] |access-date=16 February 2022}}</ref> In addition, ambitious tree-planting programmes in countries such as China, India, the United States, and Vietnam – combined with natural expansion of forests in some regions – have added more than {{convert|7|e6ha|abbr=off}} of new forests annually. As a result, the net loss of forest area was reduced to {{convert|5.2|e6ha|abbr=off}} per year between 2000 and 2010, down from {{convert|8.3|e6ha|abbr=off}} annually in the 1990s. In 2015, a study for ''[[Nature Climate Change]]'' showed that the trend has recently been reversed, leading to an "overall gain" in global biomass and forests. This gain is due especially to [[reforestation]] in China and Russia.<ref>{{cite journal|first1=Yi Y.|last1=Liu|first2=Albert I.J.M.|last2=van Dijk|first3=Richard A.M.|last3=de Jeu|first4=Josep G.|last4=Canadell|first5=Matthew F.|last5=McCabe|first6=Jason P.|last6=Evans|first7=Guojie|last7=Wang|title=Recent reversal in loss of global terrestrial biomass|journal=Nature Climate Change|volume=5|issue=5|page=470|date=30 March 2015|doi=10.1038/nclimate2581|bibcode=2015NatCC...5..470L}}</ref> New forests are not equivalent to old growth forests in terms of species diversity, resilience, and carbon capture. On 7 September 2015, the FAO released a new study stating that over the last 25 years the global [[deforestation]] rate has decreased by 50% due to improved [[forest management|management of forests]] and greater government protection.<ref>{{cite web|title=World deforestation slows down as more forests are better managed|url=http://www.fao.org/news/story/en/item/326911/icode/|website=fao.org|publisher=Food and Agriculture Organization of the United Nation|access-date=2 October 2015|url-status=live|archive-url=https://web.archive.org/web/20151012010007/http://www.fao.org/news/story/en/item/326911/icode/|archive-date=12 October 2015}}</ref><ref>{{cite web|last1=MacDicken|first1=K.|last2=Jonsson|first2=Ö.|last3=Piña|first3=L.|last4=Maulo|first4=S.|last5=Adikari|first5=Y.|last6=Garzuglia|first6=M.|last7=Lindquist|first7=E.|last8=Reams|first8=G.|last9=D'Annunzio|first9=R.|title=Global Forest Resources Assessment 2015|url=http://www.fao.org/3/a-i4793e.pdf|website=fao.org|publisher=Food and Agriculture Organization of the United Nations|date=2015|url-status=live|archive-url=https://web.archive.org/web/20151003140455/http://www.fao.org/3/a-i4793e.pdf|archive-date=3 October 2015}}</ref>

[[File:Proportion of forest in protected areas, by region, 2020.svg|thumb|Proportion of forest in protected areas, by region, 2020<ref name=":0"/>]]

There is an estimated {{convert|726|e6ha|e9acre|abbr=off}} of forest in protected areas worldwide. Of the six major world regions, South America has the highest share of forests in protected areas, at 31 percent. The area of such areas globally has increased by {{convert|191|e6ha|abbr=off}} since 1990, but the rate of annual increase slowed in 2010–2020.<ref name=":0"/>

Smaller areas of [[woodland]] in cities may be managed as [[urban forestry]], sometimes within public parks. These are often created for human benefits; [[Attention Restoration Theory]] argues that spending time in nature reduces stress and improves health, while [[Forest School (education)|forest schools]] and [[Forest kindergarten|kindergartens]] help young people to develop social as well as scientific skills in forests. These typically need to be close to where the children live.

=== Canada ===
{{Main|Forests of Canada}}
[[File:Garibaldi National Park - Garibaldi Mountain.jpg|thumb|[[Garibaldi Provincial Park]], [[British Columbia]]]]

Canada has about {{convert|4|e6km2|e6sqmi|abbr=off}} of forest land. More than 90% of forest land is publicly owned and about 50% of the total forest area is allocated for harvesting. These allocated areas are managed using the principles of sustainable forest management, which include extensive consultation with local stakeholders. About eight percent of Canada's forest is legally protected from resource development.<ref>{{cite web|url=http://www.globalforestwatch.org/country/CAN|title=Canada|publisher=Global Forest Watch Canada|access-date=28 November 2014|url-status=live|archive-url=https://web.archive.org/web/20141204160012/http://www.globalforestwatch.org/country/CAN|archive-date=4 December 2014}}</ref><ref name="nrcan">{{cite web|url=http://www.nrcan.gc.ca/forests|title=Canada's Forests|publisher=Natural Resources Canada|date=14 October 2014|access-date=28 November 2014|url-status=live|archive-url=https://web.archive.org/web/20141120200746/http://www.nrcan.gc.ca/forests|archive-date=20 November 2014}}</ref> Much more forest land—about 40 percent of the total forest land base—is subject to varying degrees of protection through processes such as integrated [[land use planning]] or defined management areas, such as certified forests.<ref name="nrcan"/>

By December 2006, over {{convert|1.2|e6km2|sqmi|abbr=off}} of forest land in Canada (about half the global total) had been certified as being sustainably managed.<ref>{{cite web|url=http://www.certificationcanada.org/en/statistics/ |publisher=Canadian Sustainable Forestry Certification Coalition |website=Certification status – Canada & the globe|title=Statistics|access-date=28 November 2014}}</ref> [[Clearcutting]], first used in the latter half of the 20th century, is less expensive, but devastating to the environment; and companies are required by law to ensure that harvested areas are adequately regenerated. Most Canadian provinces have regulations limiting the size of new clear-cuts, although some older ones grew to {{convert|110|km2|sqmi}} over several years.

The [[Canadian Forest Service]] is the government department which looks after Forests in Canada.

=== Latvia ===
[[File:Latvian Forest Tomes pagasts, Ķeguma novads, Latvia.jpg|thumb|Latvian [[Pine]] Forest in [[Ķegums Municipality]] ]]

Latvia has about {{convert|3.27|e6ha|e6acre sqmi|abbr=off}} of forest land, which equates to about 50.5% of Latvia's total area of {{convert|24938|sqmi|order=flip}} {{convert|1.51|e6ha|e6acre|abbr=off}} of forest land (46% of total forest land) is publicly owned and {{convert|1.75|e6ha|e6acre|abbr=off}} of forest land (54% of the total) is in private hands. Latvia's forests have been steadily increasing over the years, which is in contrast to many other nations, mostly due to the forestation of land not used for agriculture. In 1935, there were only {{convert|1.757|e6ha|e6acre|abbr=off}} of forest; today this has increased by more than 150%. Birch is the most common tree at 28.2%, followed by pine (26.9%), spruce (18.3%), grey alder (9.7%), aspen (8.0%), black alder (5.7%), oak/ash (1.2%), with other hardwood trees making up the rest (2.0%).<ref>{{cite web|title=Forestry in 2015 (only in Latvian) {{!}} Latvijas statistika|url=http://www.csb.gov.lv/en/dati/e-publikacijas/forestry-2015-only-latvian-45361.html|website=www.csb.gov.lv|access-date=21 December 2017|language=en|url-status=live|archive-url=https://web.archive.org/web/20171222053718/http://www.csb.gov.lv/en/dati/e-publikacijas/forestry-2015-only-latvian-45361.html|archive-date=22 December 2017}}</ref><ref>{{cite web|title=Buklets "Meža nozare Latvijā"|url=https://www.zm.gov.lv/mezi/statiskas-lapas/nozares-informacija/publikacijas/buklets-meza-nozare-latvija-?nid=1088#jump|website=www.zm.gov.lv|access-date=21 December 2017|url-status=live|archive-url=https://web.archive.org/web/20171222053235/https://www.zm.gov.lv/mezi/statiskas-lapas/nozares-informacija/publikacijas/buklets-meza-nozare-latvija-?nid=1088#jump|archive-date=22 December 2017}}</ref>

=== United States ===
In the United States, most forests have historically been affected by humans to some degree, though in recent years improved [[forestry]] practices have helped regulate or moderate large-scale impacts. The [[United States Forest Service]] estimated a net loss of about {{convert|2|e6ha|abbr=off}} between 1997 and 2020; this estimate includes conversion of forest land to other uses, including urban and suburban development, as well as [[afforestation]] and natural reversion of abandoned crop and [[pasture]] land to forest. In many areas of the United States, the area of forest is stable or increasing, particularly in many northern states. The opposite problem from flooding has plagued national forests, with loggers complaining that a lack of thinning and proper forest management has resulted in large forest fires.<ref>{{cite web|url=http://www.wildrockiesalliance.org/issues/wildfire/enn.html|archive-url=https://web.archive.org/web/20130509225620/http://www.wildrockiesalliance.org/issues/wildfire/enn.html|archive-date=9 May 2013 |title=Wildfires Ignite Forest Management Debate |publisher=Wildrockiesalliance.org |access-date=3 July 2013}}</ref><ref>{{cite book|first=Emily K.|last=Brock|title=Money Trees: The Douglas Fir and American Forestry, 1900–1944|publisher=Oregon State University Press|year=2015}}</ref>

== See also ==
{{Portal|Ecology|Environment|Trees}}
{{Columns-list|colwidth=15em|
* [[Bioproducts]]
* [[Close to nature forestry]]
* [[Cloud forest]]
* [[Dendrology]]
* [[Dendrometry]]
* [[Forest dynamics]]
* [[Forest migration]]
* [[Forest pathology]]
* [[Kelp forest]] (A forest made mostly if not entirely of [[Kelp]]; an underwater forest)
* [[List of countries by forest area]]
* [[List of national forests of the United States]]
* [[List of old-growth forests]]
* [[Mangrove forest]]
* [[Permaforestry]]
* [[REDD-plus]]
* [[Urban forest]]
* [[Wilderness]]
* [[Woodland management]]
* [[Woodland]]
}}

== Sources ==
{{Free-content attribution
| title = Global Forest Resources Assessment 2020 Key findings
| author = FAO
| publisher = FAO
| page numbers =
| source =
| documentURL = http://www.fao.org/3/CA8753EN/CA8753EN.pdf
| license statement URL = https://commons.wikimedia.org/wiki/File:Global_Forest_Resources_Assessment_2020_%E2%80%93_Key_findings.pdf
| license = CC BY-SA 3.0
}}

{{Free-content attribution
| title = The State of the World's Forests 2020. In brief – Forests, biodiversity and people
| author = FAO & UNEP
| publisher = FAO & UNEP
| page numbers =
| source =
| documentURL = https://doi.org/10.4060/ca8985en
| license statement URL = https://commons.wikimedia.org/wiki/File:The_State_of_the_World%E2%80%99s_Forests_2020._In_brief.pdf
| license = CC BY-SA 3.0
}}

== References ==
{{Reflist}}

== External links ==
{{Sister project links|auto=1|wikt=y|s=The New International Encyclopædia/Forest}}
* [http://www.barrameda.com.ar/ecology/forests-in-danger.htm Forests in danger]
* [https://web.archive.org/web/20150908225225/http://intactforests.org/ Intact Forests] with maps and reports (archived 8 September 2015)
* [http://www.fao.org/docrep/008/a0400e/a0400e00.htm Global Forest Resources Assessment 2005] by the [[Food and Agriculture Organization]]
* {{usurped|1=[https://web.archive.org/web/20080124171741/http://www.coolforests.org/ CoolForests.org – Conservation Cools the Planet]}} (archived 24 January 2008)
* [http://data.worldbank.org/indicator/AG.LND.FRST.ZS Forest area is land under natural or planted stands of trees of at least 5 meters ''in situ'', whether productive or not, and excludes tree stands in agricultural production systems]
* [http://www.google.com/publicdata/explore?ds=d5bncppjof8f9_&ctype=l&strail=false&nselm=h&met_y=ag_lnd_frst_k2&hl=en&dl=en Forest area (sq. km)] data from the [[World Bank]]'s [[World Development Indicators]], made available by Google
* {{cite news|url=http://www.bbc.co.uk/worldservice/specials/948_discovery_2008/page12.shtml|title=The first forests – Discovery 2008|last=Luck Baker|first=Andrew|date=18 November 2008|work=[[BBC Online]]}}
* {{cite web|url=http://www.conservation.org/newsroom/pressreleases/Pages/The-Worlds-10-Most-Threatened-Forest-Hotspots.aspx|title=The World's 10 Most Threatened Forest Hotspots|date=2 February 2011|publisher=[[Conservation International]]}}
* {{Cite EB1911|wstitle=Forests and Forestry|first1=Wilhelm|last1=Schlich|author-link1=Wilhelm Philipp Daniel Schlich|first2=Gifford|last2=Pinchot|author-link2=Gifford Pinchot|volume=10|pages=645–660}}

{{Forestry}}
{{Natural resources}}
{{Vegetation}}
{{Authority control}}

[[Category:Forests| ]]
[[Category:Habitats]]
[[Category:Trees]]
[[Category:Ecosystems]]