Editing Eucalyptus

{{Short description|Genus of flowering plants in the myrtle family}}{{About|the plant genus|other uses|Eucalyptus (disambiguation)}}
{{Automatic taxobox
| oldest_fossil = Eocene (possible Cenomanian record) <ref>{{cite web |title=ash near westwater, UT (Cretaceous to of the United States) |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=103148&is_real_user=1 |website=PBDB.org}}</ref>
| image = Eucalyptus tereticornis flowers, capsules, buds and foliage.jpeg
| image_caption = Buds, capsules, flowers and foliage of ''[[Eucalyptus tereticornis|E. tereticornis]]''
| display_parents = 2
| taxon = Eucalyptus
| authority = [[Charles Louis L'Héritier de Brutelle|L'Hér.]]<ref name=APC>{{cite web|title=''Eucalyptus''|url=https://biodiversity.org.au/nsl/services/apc-format/display/102507|publisher=Australian Plant Census|access-date=11 March 2019}}</ref>
| type_species = ''[[Eucalyptus obliqua]]''
| type_species_authority = [[Charles Louis L'Héritier de Brutelle|L'Hér. 1789]]
| subdivision_ranks = Species
| subdivision = *[[List of Eucalyptus species|List of ''Eucalyptus'' species]]
| synonyms = * ''Aromadendrum'' <small>W.Anderson ex R.Br., 1810</small>
* ''Eudesmia'' <small>R.Br., 1814</small>
* ''Symphyomyrtus'' <small>Schauer in J.G.C.Lehmann, 1844</small>
| synonyms_ref = <ref name="APC" />
| range_map = Eucalyptus distribution.png
| range_map_caption = Natural range
}}

'''''Eucalyptus''''' ({{IPAc-en|ˌ|juː|k|ə|ˈ|l|ɪ|p|t|ə|s}})<ref>{{cite book |title=Sunset Western Garden Book |year=1995 |pages=606–7 |publisher=Sunset Publishing Corporation |isbn=978-0-376-03851-7 |edition=6th |oclc=32666922 }}</ref> is a [[genus]] of more than 700 species of [[flowering plant]]s in the family [[Myrtaceae]]. Most species of ''Eucalyptus'' are trees, often [[Mallee (habit)|mallees]], and a few are shrubs. Along with several other genera in the tribe [[Eucalypteae]], including ''[[Corymbia]]'' and ''[[Angophora]]'', they are commonly known as [[eucalypt]]s or "gum trees". Plants in the genus ''Eucalyptus'' have bark that is either smooth, fibrous, hard, or stringy and leaves that have oil [[Gland (botany)|glands]]. The [[sepal]]s and [[petal]]s are fused to form a "cap" or [[Operculum (botany)|operculum]] over the [[stamen]]s, hence the name from Greek ''eû'' ("well") and ''kaluptós'' ("covered").<ref name=":2">{{Cite book |last=Genaust |first=Helmut |date=1976 |title=Etymologisches Wörterbuch der botanischen Pflanzennamen |url=http://dx.doi.org/10.1007/978-3-0348-7650-6 |doi=10.1007/978-3-0348-7650-6|isbn=978-3-0348-7651-3 }}</ref> The fruit is a woody [[Capsule (botany)|capsule]] commonly referred to as a "gumnut".

Most species of ''Eucalyptus'' are [[Indigenous (ecology)|native]] to Australia, and every state and territory has representative species. About three-quarters of Australian forests are eucalypt forests. Many eucalypt species have adapted to [[wildfire]], are able to resprout after fire, or have seeds that survive fire.

A few species are native to islands north of Australia, and a smaller number are only found outside the continent. Eucalypts have been grown in plantations in many other countries because they are fast-growing, have valuable timber, or can be used for [[pulpwood]], [[honey]] production, or [[essential oil]]s. In some countries, however, they have been removed because of the danger of [[forest fire]]s due to their high flammability.

==Description==
===Size and habit===
Eucalypts vary in size and [[Habit (biology)|habit]] from shrubs to tall trees. Trees usually have a single main stem or [[Trunk (botany)|trunk]] but many eucalypts are mallees that are multistemmed from ground level and rarely taller than {{convert|10|m|ft|0|abbr=off}}. There is no clear distinction between a mallee and a shrub but in eucalypts, a shrub is a mature plant less than {{convert|1|m|ftin|0|abbr=on}} tall and growing in an extreme environment. ''[[Eucalyptus vernicosa]]'' in the [[Tasmania]]n highlands, ''[[Eucalyptus yalatensis|E. yalatensis]]'' on the [[Nullarbor Plain|Nullarbor]] and ''[[Eucalyptus surgens|E. surgens]]'' growing on coastal cliffs in [[Western Australia]] are examples of eucalypt shrubs.<ref name="CANBR">{{cite web |title=Learn about eucalypts |url=http://keyserver.lucidcentral.org:8080/euclid/data/02050e02-0108-490e-8900-0e0601070d00/media/Html/learn.htm |publisher=Euclid: Centre for Australian National Biodiversity Research |access-date=14 March 2019}}</ref>

The terms "[[Mallet (habit)|mallet]]" and "[[marlock]]" are only applied to [[Western Australia]]n eucalypts. A mallet is a tree with a single thin trunk with a steeply branching habit but lacks both a [[lignotuber]] and [[Epicormic shoot|epicormic buds]]. ''[[Eucalyptus astringens]]'' is an example of a mallet. A marlock is a shrub or small tree with a single, short trunk, that lacks a lignotuber and has spreading, densely leafy branches that often reach almost to the ground. ''[[Eucalyptus platypus]]'' is an example of a marlock.<ref name="CANBR" /><ref name="Boland">{{cite book |last1=Boland |first1=Douglas J. |last2=Brooker |first2=M. Ian |last3=McDonald |first3=Maurice W. |last4=Chippendale |first4=George M. |title=Forest Trees of Australia |url=https://archive.org/details/foresttreesaustr00bola |url-access=limited |date=2006 |isbn=0643069690 |page=[https://archive.org/details/foresttreesaustr00bola/page/n363 331]|publisher=Csiro }}</ref><ref name="ANBG">{{cite web |title=Habit |url=http://www.anbg.gov.au/cpbr/cd-keys/Euclid/sample/html/habit.htm |publisher=Euclid: Australian National Botanic Gardens |access-date=29 May 2019 |archive-date=11 March 2007 |archive-url=https://web.archive.org/web/20070311014631/http://www.anbg.gov.au/cpbr/cd-keys/Euclid/sample/html/habit.htm |url-status=dead }}</ref>

''Eucalyptus'' trees, including mallets and marlocks, are single-stemmed and include ''[[Eucalyptus regnans]]'', the tallest known flowering plant on Earth.<ref name=tallest-tree>{{Cite web|url=https://www.bbc.com/earth/story/20141222-the-worlds-new-tallest-tree|title=Tasmania's giant ash trees may be world's tallest|first=Jane|last=Palmer|website=www.bbc.com|access-date=Sep 11, 2020}}</ref> The tallest reliably measured tree in Europe, ''Karri Knight'', can be found in [[Coimbra]], Portugal in Vale de Canas. It is a ''[[Eucalyptus diversicolor]]'' of 72.9 meters height and of 5.71 meters girth.<ref>Karri 'Karri Knight' in the Valle de Canas, Valle de Canas, Centro, Portugal, MonumentalTrees.com https://www.monumentaltrees.com/en/prt/centro/coimbra/4104_valledecanas/8314/ {{Webarchive|url=https://web.archive.org/web/20191227101558/https://www.monumentaltrees.com/en/prt/centro/coimbra/4104_valledecanas/8314/|date=27 December 2019}}</ref>

Tree sizes follow the convention of:
* Small: to {{convert|10|m|ft|abbr=on}} in height
* Medium-sized: {{convert|10|-|30|m|ft|abbr=on}}
* Tall: {{convert|30|-|60|m|ft|abbr=on}}
* Very tall: over {{convert|60|m|ft|abbr=on}}<ref>{{Cite web|url=https://homeguides.sfgate.com/eucalyptus-tree-information-38193.html|title=Eucalyptus Tree Information|website=Home Guides &#124; SF Gate|date=14 August 2012 |access-date=Sep 11, 2020}}</ref>
<gallery class="center">
Tasmania logging 08 Mighty tree.jpg|''[[Eucalyptus regnans]]'', a forest tree, showing crown dimension, [[Tasmania]]
TocumwalTownBeach.jpg|''[[Eucalyptus camaldulensis|E. camaldulensis]]'', immature woodland trees, showing collective crown habit, [[Murray River]], [[Tocumwal]], [[New South Wales]]
Eucalyptus cretata.jpg|''[[Eucalyptus cretata|E. cretata]]'', juvenile, showing low branching 'mallee' form, [[Melbourne]], [[Victoria, Australia|Victoria]]
Eucalyptus angustissima1.jpg|''[[Eucalyptus angustissima|E. angustissima]]'', showing shrub form, Melbourne
Eucalyptus platypus.jpg|''[[Eucalyptus platypus|E. platypus]]'', showing 'marlock' form, Melbourne
</gallery>

===Bark===
All eucalypts add a layer of [[Bark (botany)|bark]] every year and the outermost layer dies. In about half of the species, the dead bark is shed exposing a new layer of fresh, living bark. The dead bark may be shed in large slabs, in ribbons or in small flakes. These species are known as "smooth barks" and include ''[[Eucalyptus sheathiana|E. sheathiana]]'', ''[[Eucalyptus diversicolor|E. diversicolor]]'', ''[[Eucalyptus cosmophylla|E. cosmophylla]]'' and ''[[Eucalyptus cladocalyx|E. cladocalyx]]''. The remaining species retain the dead bark which dries out and accumulates. In some of these species, the fibres in the bark are loosely intertwined (in stringybarks such as ''[[Eucalyptus macrorhyncha|E. macrorhyncha]]'' or peppermints such as ''[[Eucalyptus radiata|E. radiata]]'') or more tightly adherent (as in the "boxes" such as ''[[Eucalyptus leptophleba|E. leptophleba]]''). In some species (the "ironbarks" such as ''[[Eucalyptus crebra|E. crebra]]'' and ''[[Eucalyptus jensenii|E. jensenii]]'') the rough bark is infused with gum resin.<ref name="CANBR" />

Many species are 'half-barks' or 'blackbutts' in which the dead bark is retained in the lower half of the trunks or stems—for example, ''[[Eucalyptus brachycalyx|E. brachycalyx]]'', ''[[Eucalyptus ochrophloia|E. ochrophloia]]'', and ''[[Eucalyptus occidentalis|E. occidentalis]]''—or only in a thick, black accumulation at the base, as in ''[[Eucalyptus clelandii|E. clelandii]]''. In some species in this category, for example ''[[Eucalyptus youngiana|E. youngiana]]'' and ''[[Eucalyptus viminalis|E. viminalis]]'', the rough basal bark is very ribbony at the top, where it gives way to the smooth upper stems. The smooth upper bark of the half-barks and that of the completely smooth-barked trees and mallees can produce remarkable colour and interest, for example ''[[Eucalyptus deglupta|E. deglupta]]''.<ref name=FieldGuide/>

''[[Eucalyptus globulus|E. globulus]]'' bark cells are able to photosynthesize in the absence of foliage, conferring an "increased capacity to re-fix internal CO<sub>2</sub> following partial defoliation".<ref>{{Cite journal|last=Eyles|display-authors=etal|first=A|date=2009|title=Role of corticular photosynthesis following defoliation in Eucalyptus globulus|journal=Plant, Cell & Environment|volume=32|issue=8|pages=1004–14|doi=10.1111/j.1365-3040.2009.01984.x|pmid=19344333|doi-access=free|bibcode=2009PCEnv..32.1004E }}</ref> This allows the tree to grow in less-than-ideal climates, in addition to providing a better chance of recovery from damage sustained to its leaves in an event such as a fire.<ref>{{Cite journal|last=Saveyn|display-authors=etal|first=A.|date=Summer 2010|title=Woody tissue photosynthesis and its contribution to trunk growth and bud development in young plants|url=http://onlinelibrary.wiley.com/store/10.1111/j.1365-3040.2010.02197.x/asset/j.1365-3040.2010.02197.x.pdf;jsessionid=2DF8853EB94016F034D5922B3E11AB6A.f01t04?v=1&t=j335k1pl&s=2bcf5c5de958a434bce7596540f55ee86e269f4e|journal=Plant, Cell & Environment|volume=33|issue=11|pages=1949–58|via=Wiley|doi=10.1111/j.1365-3040.2010.02197.x|pmid=20561249|doi-access=free|bibcode=2010PCEnv..33.1949S }}</ref>

Different commonly recognised types of bark include:{{cn|date=June 2024}}
* [[Stringybark]]—consists of long fibres and can be pulled off in long pieces. It is usually thick with a spongy texture.
* [[Ironbark]]—is hard, rough, and deeply furrowed. It is impregnated with dried [[kino (gum)|kino]] (a [[sap (plant)|sap]] exuded by the tree) which gives a dark red or even black colour.
* Tessellated—bark is broken up into many distinct flakes. They are [[cork (material)|corkish]] and can flake off.
* Box—has short fibres. Some also show tessellation.
* Ribbon—has the bark coming off in long, thin pieces, but is still loosely attached in some places. They can be long ribbons, firmer strips, or twisted curls.

<gallery class="center">
Apple box bark.jpg|Bark detail of ''[[Eucalyptus angophoroides|E. angophoroides]]'', the apple-topped box
Eucalyptus deglupta-trees.jpg|Coloured bark of ''[[Eucalyptus deglupta|E. deglupta]]'' native to Southeast Asia
Eucalyptus bark.jpg|'Box' bark of ''[[Eucalyptus quadrangulata|E. quadrangulata]]'', the white-topped box
Eucalyptus sideroxylon - bark.jpg|Dark, fissured '[[ironbark]]' of ''[[Eucalyptus sideroxylon|E. sideroxylon]]''
</gallery>

===Leaves===
[[File:Eucalyptus leucoxylon1.jpg|upright|thumb|''[[Eucalyptus leucoxylon]]'' var. 'Rosea' showing flowers and buds with [[Operculum (botany)|operculum]] present]]
[[File:Eucalyptus tetragona - glaucous leaves close.jpg|thumb|''[[Eucalyptus tetragona|E. tetragona]]'', showing glaucous leaves and stems]]

Nearly all ''Eucalyptus'' are [[evergreen]], but some tropical species lose their leaves at the end of the dry season. As in other members of the [[Myrtaceae|myrtle]] family, ''Eucalyptus'' leaves are covered with oil glands. The copious oils produced are an important feature of the genus. Although mature ''Eucalyptus'' trees may be towering and fully leafed, their shade is characteristically patchy because the leaves usually hang downwards.{{Citation needed|reason=This section lacks citations|date=March 2019}}

The leaves on a mature ''Eucalyptus'' plant are commonly [[lanceolate]], [[Leaf#Characteristics of the petiole|petiolate]], apparently [[Alternate leaf|alternate]] and waxy or glossy green. In contrast, the leaves of seedlings are often [[Opposite leaf|opposite]], [[Leaf#Characteristics of the petiole|sessile]] and [[Leaf#Surface of the leaf|glaucous]]. But many exceptions to this pattern exist. Many species such as ''[[Eucalyptus melanophloia|E. melanophloia]]'' and ''E. setosa'' retain the juvenile leaf form even when the plant is reproductively mature. Some species, such as ''[[Eucalyptus macrocarpa|E. macrocarpa]]'', ''[[Eucalyptus rhodantha|E. rhodantha]]'', and ''[[Eucalyptus crucis|E. crucis]]'', are sought-after ornamentals due to this lifelong juvenile leaf form. A few species, such as ''[[Eucalyptus petraea|E. petraea]]'', ''[[Eucalyptus dundasii|E. dundasii]]'', and ''[[Eucalyptus lansdowneana|E. lansdowneana]]'', have shiny green leaves throughout their life cycle. ''[[Eucalyptus caesia]]'' exhibits the opposite pattern of leaf development to most ''Eucalyptus'', with shiny green leaves in the seedling stage and dull, glaucous leaves in mature crowns. The contrast between juvenile and adult leaf phases is valuable in field identification.{{Citation needed|reason=This section lacks citations|date=March 2019}}

Four leaf phases are recognised in the development of a ''Eucalyptus'' plant: the 'seedling', 'juvenile', 'intermediate', and 'adult' phases. However, no definite transitional point occurs between the phases. The intermediate phase, when the largest leaves are often formed, links the juvenile and adult phases.<ref name=FieldGuide>Brooker & Kleinig (2001)</ref>

In all except a few species, the leaves form in pairs on opposite sides of a square stem, consecutive pairs being at right angles to each other (decussate). In some narrow-leaved species, for example ''[[Eucalyptus oleosa|E. oleosa]]'', the seedling leaves after the second leaf pair are often clustered in a detectable [[spiral]] arrangement about a five-sided stem. After the spiral phase, which may last from several to many nodes, the arrangement reverts to decussate by the absorption of some of the leaf-bearing faces of the stem. In those species with opposite adult foliage the leaf pairs, which have been formed opposite at the stem apex, become separated at their bases by unequal elongation of the stem to produce the apparently alternate adult leaves.{{Citation needed|reason=This section lacks citations|date=March 2019}}

===Flowers and fruits===
[[File:Yellow Box blossoms and gumnuts.jpg|right|thumb|''[[Eucalyptus melliodora]]'', showing flowers and opercula]]
[[File:Eucalyptus camaldulensis seeds00.jpg|thumb|Seeds of ''[[Eucalyptus camaldulensis]]'']]

The most readily recognisable characteristics of ''Eucalyptus'' species are the distinctive flowers and fruit (capsules or "gumnuts"). Flowers have numerous fluffy [[stamen]]s which may be white, cream, yellow, pink, or red; in bud, the stamens are enclosed in a cap known as an [[Operculum (botany)|operculum]] which is composed of the fused sepals or petals, or both. Thus, flowers have no petals, but instead decorate themselves with the many showy stamens. As the stamens expand, the operculum is forced off, splitting away from the cup-like base of the flower; this is one of the features that unites the genus. The woody fruits or capsules are roughly cone-shaped and have valves at the end which open to release the seeds, which are waxy, rod-shaped, about 1&nbsp;mm in length, and yellow-brown in colour. Most species do not flower until adult foliage starts to appear; ''E. cinerea'' and ''E. perriniana'' are notable exceptions.{{Citation needed|reason=This section lacks citations|date=March 2019}}

==Taxonomy==
The genus ''Eucalyptus'' was first formally described in 1789 by [[Charles Louis L'Héritier de Brutelle]] who published the description in his book ''Sertum Anglicum, seu, Plantae rariores quae in hortis juxta Londinum'' along with a description of the [[Type (biology)|type species]], ''[[Eucalyptus obliqua]]''.<ref name=APNI>{{cite web|title=''Eucalyptus''|url=https://id.biodiversity.org.au/instance/apni/455721 |publisher=APNI|access-date=11 March 2019}}</ref><ref name="l'Herit.">{{cite book |last1=L'Héritier de Brutelle |first1=Charles Louis |title=Sertum Anglicum, seu, Plantae rariores quae in hortis juxta Londinum |date=1789 |publisher=Petri Francisci Didot |location=Paris |page=11 |url=https://www.biodiversitylibrary.org/item/43456#page/35/mode/1up |access-date=11 March 2019}}</ref> The name ''Eucalyptus'' is derived from the [[Ancient Greek]] words "eu" meaning 'well' and "calyptos" 'covered', referring to the [[Operculum (botany)|operculum]] covering the flower buds.<ref name="CANBR" /><ref name="Sharr">{{cite book |last1=Sharr |first1=Francis Aubi |last2=George |first2=Alex |title=Western Australian Plant Names and Their Meanings |date=2019 |publisher=Four Gables Press |location=Kardinya, WA |isbn=9780958034180 |page=80 |edition=3rd}}</ref><ref name="Stearn">{{cite book |last1=Stearn |first1=William T. |title=Botanical Latin |date=1992 |publisher=Timber Press |location=Portland, Oregon |page=407}}</ref>

The type specimen was collected in 1777 by [[David Nelson (botanical collector)|David Nelson]], the gardener-botanist on [[James Cook|Cook's]] [[Third voyage of James Cook|third voyage]]. He collected the specimen on [[Bruny Island]] and sent it to de Brutelle who was working in [[London]] at that time.<ref name="CANBR" />

==History==
Although eucalypts must have been seen by the very early European explorers and collectors, no botanical collections of them are known to have been made until 1770 when [[Joseph Banks]] and [[Daniel Solander]] arrived at [[Botany Bay]] with [[Captain James Cook]]. There they collected specimens of ''E. gummifera'' and later, near the [[Endeavour River]] in northern ''Queensland'', ''E. platyphylla''; neither of these species was named as such at the time.{{cn|date=June 2024}}

In 1777, on Cook's third expedition, David Nelson collected a eucalypt on [[Bruny Island]] in southern [[Tasmania]]. This specimen was taken to the [[British Museum]] in [[London]], and was named ''Eucalyptus obliqua'' by the French botanist [[Charles Louis L'Héritier de Brutelle|L'Héritier]], who was working in London at the time.<ref>{{ cite book |last=L'Héritier |first=Charles Louis |author-link=Charles Louis L'Héritier de Brutelle |year=1788 |title=Sertum Anglicum, seu, Plantae rariores quae in hortis juxta Londinum : imprimis in horto regio Kewensi excoluntur, ab anno 1786 ad annum 1787 observatae |place=Paris |publisher=Petri Francisci Didot |page=11 |language=la |url=https://www.biodiversitylibrary.org/page/11832429 }}</ref> He coined the generic name from the Greek roots ''eu'' and ''calyptos'', meaning "well" and "covered" in reference to the [[operculum (botany)|operculum]] of the flower bud which protects the developing flower parts as the flower develops and is shed by the pressure of the emerging [[stamens]] at flowering.<ref name=":2" />

The name ''obliqua'' was derived from the Latin ''obliquus'', meaning "oblique", which is the [[botany|botanical]] term describing a [[leaf]] base where the two sides of the leaf blade are of unequal length and do not meet the petiole at the same place.{{cn|date=June 2024}}

''E. obliqua'' was published in 1788–89, which coincided with the European colonisation of Australia. Between then and the turn of the 19th century, several more species of ''Eucalyptus'' were named and published. Most of these were by the English botanist [[James Edward Smith (botanist)|James Edward Smith]] and most were, as might be expected, trees of the [[Sydney]] region. These include the economically valuable ''E. pilularis'', ''E. saligna'' and ''E. tereticornis''.{{cn|date=June 2024}}

The first endemic Western Australian ''Eucalyptus'' to be collected and subsequently named was the Yate (''[[Eucalyptus cornuta|E. cornuta]]'') by the French botanist [[Jacques Labillardière]], who collected in what is now the [[Esperance, Western Australia|Esperance]] area in 1792.<ref name=FieldGuide/>

Several Australian botanists were active during the 19th century, particularly [[Ferdinand von Mueller]], whose work on ''eucalypts'' contributed greatly to the first comprehensive account of the genus in [[George Bentham]]'s ''Flora Australiensis'' in 1867. The account is the most important early systematic treatment of the genus. Bentham divided it into five series whose distinctions were based on characteristics of the stamens, particularly the anthers (Mueller, 1879–84), work elaborated by [[Joseph Henry Maiden]] (1903–33) and still further by [[William Blakely|William Faris Blakely]] (1934). The anther system became too complex to be workable and more recent systematic work has concentrated on the characteristics of buds, fruits, leaves and bark.

===Species and hybrids===
{{Main|List of Eucalyptus species}}
Over 700 [[species]] of ''Eucalyptus'' are known. Some have [[divergent evolution|diverged]] from the mainstream of the [[genus]] to the extent that they are quite isolated [[genetics|genetically]] and are able to be recognised by only a few relatively invariant characteristics. Most, however, may be regarded as belonging to large or small groups of related species, which are often in geographical contact with each other and between which [[gene]] exchange still occurs. In these situations, many species appear to grade into one another, and intermediate forms are common. In other words, some species are relatively fixed genetically, as expressed in their [[morphology (biology)|morphology]], while others have not diverged completely from their nearest relatives.{{cn|date=June 2024}}

Hybrid individuals have not always been recognised as such on first collection and some have been named as new species, such as ''E. chrysantha'' (''E. preissiana'' × ''E. sepulcralis'') and ''E.'' "rivalis" (''E. marginata'' × ''E. megacarpa''). Hybrid combinations are not particularly common in the field, but some other published species frequently seen in Australia have been suggested to be hybrid combinations. For example, ''[[Eucalyptus × erythrandra]]'' is believed to be ''E. angulosa'' × ''E. teraptera'' and due to its wide distribution is often referred to in texts.<ref name=FieldGuide/>

[[Renantherin]], a phenolic compound present in the leaves of some ''Eucalyptus'' species, allows [[chemotaxonomy|chemotaxonomic]] discrimination in the sections [[renantheroideae]] and [[renantherae]]<ref>{{cite journal |doi=10.1016/S0031-9422(00)82772-7 |volume=6 |title=Polyphenols in the leaves of eucalyptus: A chemotaxonomic survey—II. |year=1967 |journal=Phytochemistry |pages=259–274 |last1=Hillis |first1=W.E.|issue=2 |bibcode=1967PChem...6..259H }}</ref> and the ratio of the amount of [[leucoanthocyanin]]s varies considerably in certain species.<ref>{{cite journal |doi=10.1016/S0031-9422(00)83632-8 |volume=5 |title=Variation in polyphenol composition within species of Eucalyptus l'herit |year=1966 |journal=Phytochemistry |pages=541–556 |last1=Hillis |first1=W.E.|issue=4 |bibcode=1966PChem...5..541H }}</ref>

===Related genera===
[[File:Tasmania logging 16 Styx a tree in danger.jpg|thumb|right|upright=0.9|''Eucalyptus regnans'' exceeding {{Convert|80|m|ft}}, in an area of extensive logging, Tasmania]]
''Eucalyptus'' is one of three similar [[genera]] that are commonly referred to as "[[eucalypt]]s", the others being ''[[Corymbia]]'' and ''[[Angophora]]''. Many species, though by no means all, are known as gum trees because they exude copious [[Kino (gum)|kino]] from any break in the [[bark (botany)|bark]] (e.g., [[Eucalyptus haemastoma|scribbly gum]]). The generic name is derived from the [[Ancient Greek|Greek]] words ευ (''eu'') "well" and καλύπτω (''kalýpto'') "to cover", referring to the [[Operculum (botany)|operculum]] on the [[Sepal|calyx]] that initially conceals the [[flower]].<ref>{{cite book |url=https://books.google.com/books?id=NJ6PyhVuecwC |title=The Names of Plants |first=D. |last=Gledhill |edition=4 |publisher=Cambridge University Press |isbn=978-0-521-86645-3 |year=2008 |page=158 |access-date=2013-11-22}}</ref>

==Distribution==
According to [[Plants of the World Online]], there are more 715 species of plants in the genus ''Eucalyptus'' and most are native to Australia; a very small number are found in adjacent areas of [[New Guinea]] and [[Indonesia]].<ref name="PoWO">{{cite web |title=''Eucalyptus'' |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:27534-1#children |publisher=Plants of the World Online |access-date=25 January 2025}}</ref> One species, ''[[Eucalyptus deglupta]],'' ranges as far north as the [[Philippines]]. Of the 15 species found outside Australia, just nine are exclusively non-Australian. Species of ''Eucalyptus'' are cultivated widely in the tropical and temperate world, including the [[Americas]], [[Europe]], [[Africa]], the [[Mediterranean Basin]], the [[Middle East]], [[China]], and the [[Indian subcontinent]]. However, the range over which many eucalypts can be planted in the temperate zone is constrained by their limited cold tolerance.<ref name="Sellers1910" />

Australia is covered by {{convert|92000000|ha|acre}} of eucalypt forest, comprising three quarters of the area covered by native forest.<ref>{{cite web|url=http://www.agriculture.gov.au/abares/forestsaustralia/profiles/eucalypt-forest|title=Eucalypt forest|access-date=29 January 2017|publisher=Commonwealth of Australia|year=2017}}</ref> The [[Blue Mountains (New South Wales)|Blue Mountains]] of southeastern Australia have been a centre of eucalypt diversification;<ref name="UNESCO_BlueMountains">{{cite web |url=https://whc.unesco.org/en/list/917|title=Greater Blue Mountains Area|date=2019|website=whc.unesco.org|publisher=UNESCO World Heritage Centre|access-date=2019-05-11}}</ref> their name is in reference to the blue haze prevalent in the area, believed derived from the volatile [[terpenoid]]s emitted by these trees.<ref name="Bohlmann2008">{{cite journal|last1=Bohlmann|first1=J.|last2=Keeling|first2=C. I.|title=Terpenoid biomaterials|journal=The Plant Journal|volume=54|issue=4|year=2008|pages=656–669|doi=10.1111/j.1365-313X.2008.03449.x|pmid=18476870|doi-access=free}}</ref>

==Fossil record==
The oldest definitive ''Eucalyptus'' fossils are from [[Patagonia]] in [[South America]], where eucalypts are no longer native, though they have been introduced from Australia. The fossils are from the early [[Eocene]] (51.9 Mya), and were found in the [[Laguna del Hunco Formation]] in [[Chubut Province]] in [[Argentina]].<ref>{{cite journal |last1=Gandolfo |first1=MA |last2=Hermsen |first2=EJ |last3=Zamaloa |first3=MC |last4=Nixon |first4=KC |last5=González |first5=CC |display-authors=etal |year=2011 |title=Oldest Known Eucalyptus Macrofossils Are from South America |journal=PLOS ONE |volume=6 |issue=6|page=e21084 |doi=10.1371/journal.pone.0021084 |bibcode=2011PLoSO...621084G |pmid=21738605 |pmc=3125177|doi-access=free }}</ref><ref>{{Cite journal |last1=Giraldo |first1=L. Alejandro |last2=Wilf |first2=Peter |last3=Donovan |first3=Michael P. |last4=Kooyman |first4=Robert M. |last5=Gandolfo |first5=Maria A. |date=28 November 2024 |title=Fossil insect-feeding traces indicate unrecognized evolutionary history and biodiversity on Australia's iconic Eucalyptus |journal=[[New Phytologist]] |language=en |volume=245 |issue=4 |pages=1762–1773 |doi=10.1111/nph.20316 |issn=0028-646X |pmc=11754931 |pmid=39605238 }}</ref> This shows that the genus had a [[Gondwana]]n distribution. Fossil leaves also occur in the Miocene of New Zealand, where the genus is not native today, but again have been introduced from Australia.<ref>{{cite web|url=https://mikepole.wordpress.com/2014/09/22/eucalyptus-fossils-in-new-zealand-the-thin-end-of-the-wedge/|title=Eucalyptus fossils in New Zealand - the thin end of the wedge - Mike Pole|date=2014-09-22}}</ref>

Despite the prominence of ''Eucalyptus'' in modern Australia, estimated to contribute some 75% of the modern vegetation, the fossil record is very scarce throughout much of the [[Cenozoic]], and suggests that this rise to dominance is a geologically more recent phenomenon. The oldest reliably dated macrofossil of ''Eucalyptus'' is a 21-million-year-old tree-stump encased in basalt in the upper Lachlan Valley in [[New South Wales]]. Other fossils have been found, but many are either unreliably dated or else unreliably identified.<ref name="Hill, R. S 1994">{{cite book |first=R.S. |last=Hill |chapter=The history of selected Australian taxa |chapter-url={{GBurl|loBrTOJDojoC|p=390}} |title=History of the Australian vegetation: Cretaceous to Recent |publisher=Cambridge University Press |date=1994 |isbn=978-0-521-40197-5 |pages=390 }}</ref>

It is useful to consider where ''Eucalyptus'' fossils have not been found. Extensive research has gone into the fossil floras of the [[Paleocene]] to [[Oligocene]] of South-Eastern Australia, and has failed to uncover a single ''Eucalyptus'' specimen. Although the evidence is sparse, the best hypothesis is that in the mid-Tertiary, the continental margins of Australia only supported more mesic noneucalypt vegetation, and that eucalypts probably contributed to the drier vegetation of the arid continental interior. With the progressive drying out of the continent since the [[Miocene]], eucalypts were displaced to the continental margins, and much of the mesic and rainforest vegetation that was once there was eliminated.<ref name="Hill, R. S 1994"/>

The current superdominance of ''Eucalyptus'' in Australia may be an artefact of human influence on its ecology. In more recent sediments, numerous findings of a dramatic increase in the abundance of ''Eucalyptus'' pollen are associated with increased charcoal levels. Though this occurs at different rates throughout Australia, it is compelling evidence for a relationship between the artificial increase of fire frequency with the arrival of Aboriginals and increased prevalence of this exceptionally fire-tolerant genus.<ref name="Hill, R. S 1994"/>

==Tall timber==
Several eucalypt species are among the [[List of tallest trees|tallest trees]] in the world. ''[[Eucalyptus regnans]]'', the Australian 'mountain ash', is the tallest of all flowering plants ([[angiosperm]]s); today, the tallest measured specimen named [[Centurion (tree)|Centurion]] is {{convert|100.5|m|ft|0|abbr=on}} tall.<ref name=tallest>{{cite web|url=http://www.gianttrees.com.au/tall.htm |title=Tasmania's Ten Tallest Giants|publisher=Tasmanian Giant Trees Consultative Committee|access-date=2009-01-07 |archive-url=https://web.archive.org/web/20080718214955/http://www.gianttrees.com.au/tall.htm <!-- Bot retrieved archive --> |archive-date=2008-07-18}}</ref> [[Coast Douglas-fir]] is about the same height; only [[Sequoia sempervirens|coast redwood]] is taller, and they are [[conifer]]s ([[gymnosperm]]s). Six other eucalypt species exceed 80 metres in height: ''[[Eucalyptus obliqua]]'', ''[[Eucalyptus delegatensis]]'', ''[[Eucalyptus diversicolor]]'', ''[[Eucalyptus nitens]]'', ''[[Eucalyptus globulus]]'' and ''[[Eucalyptus viminalis]]''.{{cn|date=June 2024}}

==Frost intolerance==
Most eucalypts are not tolerant of severe cold.<ref name="Sellers1910">{{cite book |last=Sellers |first=C.H. |title=Eucalyptus: Its History, Growth, and Utilization|url=https://archive.org/details/eucalyptusitshis00sell|year=1910|publisher=A.J. Johnston|page=[https://archive.org/details/eucalyptusitshis00sell/page/13 13] |oclc=903889267}}</ref><ref name="Sekella2003">{{cite journal |last=Sekella |first=D. |title=Cold Hardiness of Five Eucalypts in Northern California |journal=Pacific Horticulture |volume=64 |issue=1 |date=January 2003 |url=http://www.pacifichorticulture.org/articles/cold-hardiness-of-five-eucalypts-in-northern-california/ |access-date=2016-08-31}}</ref><ref name="Hasey1990">{{cite journal |last1=Hasey |first1=J. K. |last2=Connor |first2=J. M. |title=Eucalyptus shows unexpected cold tolerance |journal=California Agriculture |volume=44 |issue=2 |pages=25–27 |date=1 March 1990 |doi=10.3733/ca.v044n02p25 |doi-broken-date=1 November 2024 |url=http://calag.ucanr.edu/Archive/?article=ca.v044n02p25 |access-date=2016-08-31 |doi-access=free |archive-date=2016-09-15 |archive-url=https://web.archive.org/web/20160915090629/http://calag.ucanr.edu/Archive/?article=ca.v044n02p25 |url-status=dead }}</ref> Eucalypts do well in a range of climates but are usually damaged by anything beyond a light frost of {{convert|-5|°C|0|abbr=on}};<ref name="Sellers1910" /><ref name="Sekella2003" /><ref name="Hasey1990" /> the hardiest are the snow gums, such as ''[[Eucalyptus pauciflora]]'', which is capable of withstanding cold and frost down to about {{convert|-20|°C|0|abbr=on}}.<ref name=KEW>{{cite web|title=''Eucalyptus pauciflora''|url=http://apps.kew.org/trees/?page_id=115|archive-url=https://web.archive.org/web/20130312182144/http://apps.kew.org/trees/?page_id=115|archive-date=2013-03-12|url-status=dead|publisher=[[Kew Royal Botanic Gardens]]|access-date=26 July 2013}}</ref> Two subspecies, ''E. pauciflora subsp. niphophila'' and ''E. pauciflora subsp. debeuzevillei'' in particular are even hardier and can tolerate even quite severe winters. Several other species, especially from the high plateau and mountains of central [[Tasmania]] such as ''[[Eucalyptus coccifera]]'', ''[[Eucalyptus subcrenulata]]'' and ''[[Eucalyptus gunnii]]'',<ref name=ATS>{{cite web|title=''Eucalyptus gunnii'' subsp. ''divaricata'' (Miena Cider Gum)|work=[Australian] Threatened species & ecological communities|publisher=Dept. of the Environment [Australia]|url=http://www.environment.gov.au/node/16369|access-date=23 November 2013}}</ref> have also produced extreme cold-hardy forms and it is seed procured from these [[genetics|genetically]] hardy strains that are planted for ornament in colder parts of the world.

==Animal relationships==
An [[essential oil]] extracted from ''Eucalyptus'' leaves contains compounds that are powerful natural disinfectants and can be toxic in large quantities. Several [[marsupial herbivore]]s, notably [[koala]]s and some [[Phalangeriformes|possums]], are relatively tolerant of it. The close correlation of these oils with other more potent toxins called formylated [[phloroglucinol]] compounds ([[euglobal]]s, [[macrocarpal]]s and [[sideroxylonal]]s)<ref>{{Cite journal|pmid=10913843|year=2000|last1=Eschler|first1=BM|last2=Pass|first2=DM|last3=Willis|first3=R|last4=Foley|first4=WJ|title=Distribution of foliar formylated phloroglucinol derivatives amongst Eucalyptus species|volume=28|issue=9|pages=813–824|journal=Biochemical Systematics and Ecology|doi=10.1016/S0305-1978(99)00123-4|bibcode=2000BioSE..28..813E }}</ref> allows koalas and other [[marsupial]] species to make food choices based on the smell of the leaves. For koalas, these compounds are the most important factor in leaf choice.

A wide variety of insects also feed exclusively on ''Eucalyptus'' leaves, such as beetles in the genus ''[[Paropsisterna]]''.<ref>{{Cite web |title=Genus Paropsisterna |url=https://bugguide.net/node/view/115171 |access-date=2024-10-31 |website=bugguide.net |language=en}}</ref>

The [[eusocial]] beetle ''[[Austroplatypus incompertus]]'' makes and defends its galleries exclusively inside eucalypts, including some species of ''Eucalyptus'' and ''Corymbia''.<ref name="USDA">{{cite web |last1=Kliejunas |first1=John T. |last2=Burdstall |first2=Harold H. |last3=DeNitto |first3=Gregg A. |last4=Eglitis |first4=Andris |last5=Haugen |first5=Dennis A. |last6=Haverty |first6=Michael I. |last7=Micales |first7=Jessie A. |last8=Tkacz |first8=Borys M. |last9=Powell |first9=Mark R. |title=Pest Risk Assessment of the Importation Into the United States of Unprocessed Logs and Chips of Eighteen Eucalypt Species From Australia |url=https://www.fpl.fs.usda.gov/documnts/fplgtr/fplgtr137.pdf |publisher=United States Department of Agriculture |access-date=28 October 2023}}</ref>

{{Gallery
|Koala-ag1.jpg|[[Koala]] (''Phascolarctos cinereus'') eating the leaves
|Sawfly larvae - Pergidae sp.jpg|[[Spitfire sawfly|Sawfly]] larvae feeding on the leaves
}}

==Diseases on plants==
Fungal species ''[[Mycosphaerella]]'' and ''[[Teratosphaeria]]'' have been associated with leaf disease on various ''Eucalyptus'' species.
<ref name="Quaedvlieg2014">{{cite journal |last1=Quaedvlieg |first1=W. |last2=Binder |first2=M. |last3=Groenewald |first3=J.Z. |last4=Summerell |first4=B.A. |last5=Carnegie |first5=A.J. |last6=Burgess |first6=T.I. |last7=Crous |first7=P.W. |title=Introducing the Consolidated Species Concept to resolve species in the Teratosphaeriaceae |journal=Persoonia - Molecular Phylogeny and Evolution of Fungi |date=December 2014 |volume=33 |pages=1–40 |doi=10.3767/003158514X681981 |pmid=25737591|pmc=4312929 }}</ref> Several fungal species from [[Teratosphaeriaceae]] family are causal agents in leaf diseases and stem cankers of ''Eucalyptus'' in [[Uruguay]],<ref name="perez2009">{{Cite journal | doi = 10.1111/j.1439-0329.2009.00598.x | volume = 39 | issue = 5 | pages = 349–360 | last = Pérez | first = C. A. |author2=M. J. Wingfield |author3=N. A. Altier |author4=R. A. Blanchette  | title = Mycosphaerellaceae and Teratosphaeriaceae associated with Eucalyptus leaf diseases and stem cankers in Uruguay | journal = Forest Pathology | date = October 2009 | bibcode = 2009FoPat..39..349P | citeseerx = 10.1.1.722.6028 }}</ref><ref name="perez2013">{{Cite journal | doi = 10.1016/j.funbio.2012.12.002 | pmid = 23452947 | volume = 117 | issue = 2 | pages = 94–102 | last = Pérez | first = C. A. |author2=M. J. Wingfield |author3=N. Altier |author4=R. A. Blanchette  | title = Species of Mycosphaerellaceae and Teratosphaeriaceae on native Myrtaceae in Uruguay: evidence of fungal host jumps | journal = Fungal Biology | date = 2013-03-01 | bibcode = 2013FunB..117...94P | hdl = 2263/30796 | hdl-access = free }}</ref> and [[Australia]].<ref name="crous2009">{{Cite journal | doi = 10.3767/003158509X479531 | pmid = 20198165 | pmc = 2802729 | volume = 23 | pages = 119–146 | last = Crous | first = P. W. |author2=B. A. Summerell |author3=A. J. Carnegie |author4=M. J. Wingfield |author5=Johannes Z. Groenewald  | title = Novel species of Mycosphaerellaceae and Teratosphaeriaceae | journal = Persoonia | date = 2009-12-31 }}</ref><ref name="perez2012">{{Cite journal | doi = 10.1111/j.1365-294X.2012.05714.x | pages = 4452–71| last = Pérez | first = Guillermo |author2=Bernard Slippers |author3=Michael J. Wingfield |author4=Brenda D. Wingfield |author5=Angus J. Carnegie |author6=Treena I. Burgess  | title = Cryptic species, native populations and biological invasions by a eucalypt forest pathogen | journal = Molecular Ecology | date = 2012-08-10 | volume=21 | issue = 18| pmid=22882273| bibcode = 2012MolEc..21.4452P| hdl = 2263/19758| s2cid = 2835791| url = http://researchrepository.murdoch.edu.au/id/eprint/10815/| hdl-access = free }}</ref>

==Adaptation to fire==
{{main|Bushfires in Australia}}
[[File:Epicormic Shoots from an Epicormic Bud on Eucalyptus following Bushfire 2, near Anglers Rest, Vic, Aust, jjron 27.3.2005.jpg|right|thumb|[[Epicormic shoots]] sprouting vigorously from epicormic buds beneath the [[Bushfires in Australia|bushfire]] damaged bark on the trunk of a ''Eucalyptus'' tree]]
[[File:Eucalyptus forest2.jpg|thumb|''Eucalyptus'' forest in a state of regeneration]]
[[File:Post bushfire epicormic regrowth in eucalyptus, Blue Mountains, NSW, Australia 05.jpg|thumb|Epicormic growth shooting after the [[2019–2020 Australian bushfire season]]]]
Eucalypts originated between 35 and 50&nbsp;million years ago, not long after [[Australia-New Guinea]] separated from [[Gondwana]], their rise coinciding with an increase in fossil charcoal deposits (suggesting that fire was a factor even then), but they remained a minor component of the Tertiary rainforest until about 20&nbsp;million years ago, when the gradual drying of the continent and depletion of soil nutrients led to the development of a more open forest type, predominantly ''[[Casuarina]]'' and ''[[Acacia]]'' species.{{cn|date=June 2024}}

The two valuable timber trees, alpine ash ''[[Eucalyptus delegatensis|E. delegatensis]]'' and Australian mountain ash ''[[Eucalyptus regnans|E. regnans]]'', are killed by fire and only regenerate from seed. The same 2003 bushfire that had little impact on forests around [[Canberra]] resulted in thousands of hectares of dead ash forests. However, a small amount of ash survived and put out new ash trees as well.{{cn|date=June 2024}}

===Fire hazard===
[[File:San Diego Firestorm 2007.jpg|thumb|right|''Eucalyptus'' trees bent over due to the high winds and heat of the [[October 2007 California wildfires]]. They are located in the [[San Dieguito River Park]] of San Diego County and leaning west.]]
''Eucalyptus'' oil is highly flammable and at high enough temperatures the oil expands quickening the spread of wildfires.<ref name=SantosProblems>{{cite web |url=http://www.library.csustan.edu/bsantos/section3.htm |archive-url=https://web.archive.org/web/20060910202218/http://www.library.csustan.edu/bsantos/section3.htm |url-status=dead |archive-date=2006-09-10 |title=Section Three: Problems, Cares, Economics, and Species |work=The Eucalyptus of California |first=Robert L. |last=Santos |publisher=California State University |year=1997}}</ref><ref>{{cite web |url=http://www.robertsward.com/eucmore.htm |title=Eucalytus Roulette (con't) |publisher=Robert Sward: Poet, Novelist and Workshop Leader |url-status=dead |archive-url=https://web.archive.org/web/20070726134311/http://www.robertsward.com/eucmore.htm |archive-date=2007-07-26 }}</ref> [[Bushfires in Australia|Bushfires]] can travel easily through the oil-rich air of the tree crowns.<ref>{{cite conference |last1=Dold |first1=J.W. |last2=Weber |first2=R.O. |last3=Gill |first3=M. |date=2005 |title=Unusual phenomena in an extreme bushfire |book-title=Proceedings of the 5th Asia Pacific Conference on Combustion, ASPACC 2005 |isbn=9780975785508 |oclc=156798384 |url=https://eprints.maths.manchester.ac.uk/877/}}</ref><ref>{{cite journal |first=C. |last=Williams |title=Ignition impossible: When wildfires set the air alight |journal=New Scientist |volume=195 |issue=2615 |pages=38–40 |date=2007 |doi=10.1016/S0262-4079(07)61969-1 }}</ref> Eucalypts obtain long-term fire survivability from their ability to regenerate from [[epicormic shoot|epicormic buds]] situated deep within their thick bark, or from [[lignotuber]]s,<ref name=Reid/> or by producing [[Serotiny|serotinous]] fruits.<ref>{{Cite magazine|url=https://www.wired.co.uk/article/australia-wildfire-recovery|title=This is how Australia could recover from its devastating wildfires|last=Beall|first=Abigail|date=2020-01-13|magazine=Wired UK|access-date=2020-01-16|issn=1357-0978}}</ref>

In seasonally dry climates oaks are often fire-resistant, particularly in open grasslands, as a grass fire is insufficient to ignite the scattered trees. In contrast, a ''Eucalyptus'' forest tends to promote fire because of the volatile and highly combustible oils produced by the leaves, as well as the production of large amounts of [[Plant litter|litter]] high in phenolics, preventing its breakdown by [[Fungus|fungi]] and thus accumulating as large amounts of dry, combustible fuel.<ref name=Reid>Reid, J.B. & Potts, B.M. (2005). Eucalypt Biology. In: Reid ''et al.'' (eds.) Vegetation of Tasmania., pp. 198–223. Australian Government.</ref> Consequently, dense eucalypt plantings may be subject to catastrophic firestorms. In fact, almost thirty years before the [[Oakland firestorm of 1991]], a study of ''Eucalyptus'' in the area warned that the litter beneath the trees builds up very rapidly and should be regularly monitored and removed.<ref>{{cite journal |title=Eucalyptus: Fuel Dynamics and Fire Hazard in the Oakland Hills |journal=California Agriculture |date=September 1973 |url=http://ucce.ucdavis.edu/files/repositoryfiles/ca2709p13-64054.pdf |access-date=2011-07-07 |author1=J. K. Agee |author2=R. H. Wakimoto |author3=E. F. Darly |author4=H. H. Biswell |archive-url=https://web.archive.org/web/20110927074519/http://ucce.ucdavis.edu/files/repositoryfiles/ca2709p13-64054.pdf |archive-date=2011-09-27 |url-status=dead }}</ref> It has been estimated that 70% of the energy released through the combustion of vegetation in the Oakland fire was due to ''Eucalyptus''.<ref name=NPS>{{cite report |title=A Transcontinental Legacy: Fire Management, Resource Protection, and the Challenges of Tasmanian Blue Gum |publisher=U.S. Government Printing Office |date=March 2006 |url=http://biomass.forestguild.org/casestudies/1001/Eucalyptus.pdf |access-date=2011-07-09 |url-status=dead |archive-url=https://web.archive.org/web/20110811011531/http://biomass.forestguild.org/casestudies/1001/Eucalyptus.pdf |archive-date=2011-08-11 }}</ref> In a [[National Park Service]] study, it was found that the fuel load (in tons per acre) of non-native ''Eucalyptus'' woods is almost three times as great as native oak woodland.<ref name=NPS/>

During [[World War II]], one California town cut down their ''Eucalyptus'' trees to "about a third of their height in the vicinity of [[Anti-aircraft warfare|anti-aircraft guns]]" because of the known fire-fueling qualities of the trees, with the mayor telling a newspaper reporter, "If a [[Shell (projectile)|shell]] so much as hits a leaf, it's supposed to explode."<ref>Treanor, Tom, "The Home Front," ''Los Angeles Times'', 1942-01-27, p. A. </ref>

==<span id="Unexpected branch drops"></span>Falling branches==
[[File:Fallen Eucalyptus camaldulensis limbs (1).jpg|thumb|Fallen ''E. camaldulensis'' limbs on a walking track]]
Some species of ''Eucalyptus'' drop branches unexpectedly. In Australia, [[Parks Victoria]] warns campers not to camp under [[Eucalyptus camaldulensis|river red gums]].<ref name=ParksVicTreeRisk>{{cite web|title=Tree Risk|url=http://www.parkweb.vic.gov.au/1process_content.cfm?section=185&page=2|publisher=Parks Victoria|access-date=22 November 2013|archive-url=https://web.archive.org/web/20110707030617/http://www.parkweb.vic.gov.au/1process_content.cfm?section=185&page=2 |archive-date=2011-07-07 |url-status=dead}}</ref> Some councils in Australia such as [[Gosnells, Western Australia]], have removed eucalypts after reports of damage from dropped branches, even in the face of lengthy, well publicised protests to protect particular trees.<ref name=WAToday>{{cite web|last=Thomson|first=Chris|title=Tree man's gum an Eastern States 'widow maker'|url=http://www.watoday.com.au/wa-news/tree-mans-gum-an-eastern-states-widow-maker-20100310-py5r.html|publisher=WA Today|access-date=29 January 2011|date=2010-03-10}}</ref> A former Australian National Botanic Gardens director and consulting arborist, Robert Boden, has been quoted referring to "summer branch drop".<ref name=CanberraTimes>{{cite news |last=Thistleton|first=John |title=Beware of falling gum trees in summer heat, arborists warn |url=http://www.canberratimes.com.au/news/local/news/general/beware-of-falling-gum-trees-in-summer-heat-arborists-warn/215094.aspx |access-date=2013-11-22 |newspaper=Canberra Times|archive-url=https://web.archive.org/web/20080918060141/http://www.canberratimes.com.au/news/local/news/general/beware-of-falling-gum-trees-in-summer-heat-arborists-warn/215094.aspx |archive-date=2008-09-18 |url-status=dead}}</ref> Dropping of branches is recognised in Australia literature through the fictional death of Judy in ''[[Seven Little Australians]]''. Although all large trees can drop branches, the density of ''Eucalyptus'' wood is high<ref>{{cite web|last1=Seely|first1=Oliver|title=Physical Properties of Common Woods|url=http://www.csudh.edu/oliver/chemdata/woods.htm|website=California State University, Dominguez Hills|access-date=8 September 2017|archive-date=9 June 2010|archive-url=https://web.archive.org/web/20100609005909/http://www.csudh.edu/oliver/chemdata/woods.htm|url-status=dead}}</ref> due to its high resin content,<ref name="Hiwale2015">{{cite book|first=S.|last=Hiwale|title=Sustainable Horticulture in Semiarid Dry Lands|url=https://books.google.com/books?id=fr1nBwAAQBAJ&q=resin%20content|date=16 March 2015|publisher=Springer|isbn=978-8132222446}}</ref> increasing the hazard.

==Cultivation and uses==
[[File:Eucalyptus niphophila - Mount Ginini - Namadgi National Park.jpg|thumb|[[Eucalyptus pauciflora|Snow gum]] in [[Namadgi National Park]]]]
Eucalypts were introduced from [[Australia]] to the rest of the world following the [[James Cook|Cook]] expedition in 1770. Collected by [[Joseph Banks|Sir Joseph Banks]], [[botanist]] on the expedition, they were subsequently introduced to many parts of the world, notably [[California]], southern Europe, Africa, the [[Middle East]], South Asia and South America. About 250 species are under cultivation in California.<ref>{{cite book |author-link=Matt Ritter |first=Matt  |last=Ritter |title=The Digital Jepson Manual |publisher=University of California Press |edition=2nd |date=2012 |isbn=978-0-520-95137-2 |pages=913–4 |jstor=10.1525/j.ctt1pn9sv |oclc=797855571 |url=https://www.jstor.org/stable/10.1525/j.ctt1pn9sv }}</ref> In [[Portugal]] and also [[Spain]], eucalypts have been grown in plantations for the production of [[pulpwood]]. ''Eucalyptus'' are the basis for several industries, such as sawmilling, pulp, charcoal and others. Several species have become [[invasive species|invasive]] and are causing major problems for local ecosystems, mainly due to the absence of [[wildlife corridor]]s and rotations management.{{citation needed|date=April 2021}}

Eucalypts have many uses which have made them [[Economics|economically]] important trees, and they have become a [[cash crop]] in poor areas such as [[Timbuktu]], Mali<ref name=Timbuktu>[[WorldWatch Institute]]. (2007) ''[[State of the World (book series)|State of the World]]: Our Urban Future''.</ref>{{Rp|22|date=May 2009}} and the [[Peru]]vian [[Andes]],<ref name=Peruvian>{{cite journal |first=J. |last=Luzar |title=The Political Ecology of a "Forest Transition": Eucalyptus forestry in the Southern Peruvian |journal=Ethnobotany Research & Applications |volume=5 |pages=85–93 |date=2007 |doi=10.17348/era.5.0.85-93 |url=http://ethnobotanyjournal.org/index.php/era/article/download/121/107|doi-access=free |hdl=10125/222 |hdl-access=free }}</ref> despite concerns that the trees are [[Invasive species|invasive]] in some environments like those of [[South Africa]].<ref name=invasive/> Best-known are perhaps the varieties [[Eucalyptus diversicolor|karri]] and [[Eucalyptus melliodora|yellow box]]. Due to their fast growth, the foremost benefit of these trees is their wood. They can be chopped off at the root and grow back again. They provide many desirable characteristics for use as [[Ornamental plant|ornament]], timber, firewood and pulpwood. Eucalyptus wood is also used in a number of industries, from fence posts (where the oil-rich wood's high resistance to decay is valued) and charcoal to [[cellulose]] extraction for [[biofuel]]s. Fast growth also makes eucalypts suitable as [[windbreak]]s and to reduce [[erosion]].{{cn|date=June 2024}}<ref>{{Cite journal |last=Minshew |first=Chimene |date=April 2021 |title=Growth and Survival of Eucalyptus species as Windbreak Plantings in California's Central Valley |url=https://www.nrcs.usda.gov/plantmaterials/capmctn13794.pdf |journal=TECHNICAL NOTES - U.S. Department of Agriculture}}</ref>

Some ''Eucalyptus'' species have attracted attention from horticulturists, [[development economics|global development]] researchers, and environmentalists because of desirable traits such as being fast-growing sources of wood, producing oil that can be used for cleaning and as a natural [[insecticide]], or an ability to be used to drain [[swamp]]s and thereby reduce the risk of [[malaria]]. [[Eucalyptus oil]] finds many uses like in fuels, fragrances, insect repellence and antimicrobial activity. ''Eucalyptus'' trees show [[allelopathic]] effects; they release compounds which inhibit other plant species from growing nearby. Outside their natural ranges, eucalypts are both lauded for their beneficial economic impact on poor populations<ref name=Peruvian/><ref name=Timbuktu/>{{Rp|22|date=May 2009}} and criticised for being "water-guzzling" [[Invasive species|aliens]],<ref name=invasive/> leading to controversy over their total impact.<ref name=SantosProblems/>

Eucalypts draw a tremendous amount of water from the soil through the process of [[transpiration]]. They have been planted (or re-planted) in some places to lower the [[water table]] and reduce [[soil salination]]. Eucalypts have also been used as a way of reducing [[malaria]] by draining the soil in Algeria, Lebanon, Sicily,<ref>{{cite web |url=http://www.botanical.com/botanical/mgmh/e/eucaly14.html |title=A Modern Herbal:Eucalyptus |author=Mrs. M. Grieve |access-date=2005-01-27}}</ref> elsewhere in [[Europe]], in the Caucasus (Western [[Georgia (country)|Georgia]]), and California.<ref>{{cite web |author=Santos, Robert L |url=http://www.library.csustan.edu/bsantos/section2.htm |archive-url=https://web.archive.org/web/20060910202206/http://www.library.csustan.edu/bsantos/section2.htm |url-status=dead |archive-date=2006-09-10 |title=Section Two: Physical Properties and Uses |work=The Eucalyptus of California |publisher=California State University |year=1997}}</ref> Drainage removes [[swamp]]s which provide a habitat for [[mosquito]] [[larva]]e, but can also destroy ecologically productive areas. This drainage is not limited to the soil surface, because the ''Eucalyptus'' roots are up to {{convert|2.5|m|ftin|abbr=on}} in length and can, depending on the location, even reach the [[phreatic zone]].{{citation needed|date=February 2012}}

===Pulpwood===
{{see also|Paper industry}}
''Eucalyptus'' is the most common short fibre source for [[pulpwood]] to make [[Pulp (paper)|pulp]].<ref name=marketpulp>{{Cite book|last=Nanko |first=Hirko |author2=Button, Allan |author3=Hillman, Dave |title=The World of Market Pulp |publisher=WOMP, LLC |year=2005 |location=Appleton, WI, USA |pages=107–9 |isbn=978-0-615-13013-2 }}</ref> The types most often used in [[papermaking]] are ''[[Eucalyptus globulus]]'' (in temperate areas) and the ''[[Eucalyptus urophylla]]'' x ''[[Eucalyptus grandis]]'' hybrid (in the tropics).<ref>{{cite web|url=https://www.goldenscapetreeafrica.org/eucalyptus.html|website=GoldenscapeTreeAfrica.org|title=Goldenscape Tree Africa|publisher=Goldenscape Tree Africa|access-date=2018-03-27|archive-url=https://web.archive.org/web/20180327212013/https://www.goldenscapetreeafrica.org/eucalyptus.html|archive-date=2018-03-27|url-status=dead}}</ref> The fibre length of ''Eucalyptus'' is relatively short and uniform with low coarseness compared with other hardwoods commonly used as pulpwood. The fibres are slender, yet relatively thick walled. This gives uniform paper formation and high [[opacity (optics)|opacity]] that are important for all types of [[fine paper]]s. The low coarseness is important for high quality [[coated paper]]s.<ref name=marketpulp /> ''Eucalyptus'' is suitable for many [[tissue paper]]s as the short and slender fibres gives a high number of fibres per gram and low coarseness contributes to softness.<ref name=marketpulp />

===''Eucalyptus'' oil===
{{Main |Eucalyptus oil}}
[[Eucalyptus oil]] is readily [[steam distillation|steam distilled]] from the leaves and can be used for cleaning and as an industrial solvent, as an antiseptic, for deodorising, and in very small quantities in [[food]] supplements, especially [[sweets]], [[cough drops]], [[toothpaste]] and decongestants. It has insect-repellent properties,<ref>{{cite journal |last1=Jahn |first1=Gary |title=Ant Repellent Activity of Eucalyptus Extracts in Choice Tests, 1988 |journal=Insecticide and Acaricide Tests |date=1 January 1991 |volume=16 |issue=1 |page=293 |url=https://academic.oup.com/amt/article/16/1/293/4573406 |access-date=16 January 2019}}</ref> and serves as an active ingredient in some commercial mosquito-repellents.<ref>{{cite journal |last1=Fradin |first1=Mark S. |last2=Day |first2=John F. |title=Comparative Efficacy of Insect Repellents against Mosquito Bites |journal=New England Journal of Medicine |volume=347 |issue=1 |pages=13–18 |date=7 October 2009 |doi=10.1056/nejmoa011699 |pmid=12097535 |doi-access=free }}</ref> [[Aromatherapy|Aromatherapists]] have adopted ''Eucalyptus'' oils for a wide range of purposes.<ref>
{{cite book|year=2002|chapter=Composition of essential oils and other materials: Popular essences|editor1-last=Clarke|editor1-first=Sue|title=Essential Chemistry for Aromatherapy|url=https://books.google.com/books?id=3n8KkOb9ZuYC|edition=2|location=Edinburgh|publisher=Elsevier Health Sciences|publication-date=2009|page=175|isbn=9780443104039|access-date=2020-04-28|quote=The eucalyptus essential oils find widespread applications [...]. For aromatherapy, the oils can be used for skin care, the respiratory system, the nervous system, the urino-genital system and the musculo-skeletal system.
}}</ref> ''[[Eucalyptus globulus]]'' is the principal source of ''Eucalyptus'' oil worldwide.

===Musical instruments===
Eucalypt wood is also commonly used to make [[didgeridoo]]s, a traditional [[Australian Aboriginals|Australian Aboriginal]] [[wind instrument]].<ref>{{cite web|url=https://www.didjshop.com/shop1/HowDidgeridooIsMade-MythAndFacts.html|title=How a Didgeridoo is Made - Myth and Facts|access-date=28 February 2018|publisher=Didjshop}}</ref> The trunk of the tree is hollowed out by termites, and then cut down if the bore is of the correct size and shape.<ref>{{cite web|url=https://www.didgeridoodojo.com/didgeridoo-buyers-guide/what-material-wood-should-my-didgeridoo-be-made-fro/|title=What Material or Wood Should my Didgeridoo be made from?|access-date=28 February 2018|publisher=Didgeridoodojo}}</ref>

Eucalypt wood is also being used as a [[tonewood]] and a fingerboard material for acoustic guitars, notably by the California-based Taylor company.<ref>{{cite web |last1=Sampson |first1=William |title=Taylor debuts guitars with urban sourced eucalyptus wood |url=https://www.woodworkingnetwork.com/news/woodworking-industry-news/taylor-debuts-guitars-urban-sourced-eucalyptus-wood |website=Woodworking Network |date=30 September 2022 |publisher=CCI Media |access-date=18 May 2023}}</ref>

===Dyes===
All parts of ''Eucalyptus'' may be used to make [[dye]]s that are substantive on [[protein]] fibres (such as [[silk]] and [[wool]]), simply by processing the plant part with [[water]]. Colours to be achieved range from yellow and orange through green, tan, chocolate and deep rust red.<ref>India Flint, Botanical Alchemist. "The Scent of Eucalyptus." http://www.indiaflint.com/page6.htm {{Webarchive|url=https://web.archive.org/web/20100614044746/http://www.indiaflint.com/page6.htm |date=2010-06-14 }}</ref>

===Prospecting===
''Eucalyptus'' trees in the Australian outback draw up gold from tens of metres underground through their root system and deposit it as particles in their leaves and branches. A Maia detector for x-ray elemental imaging at the [[Australian Synchrotron]] clearly showed deposits of gold and other metals in the structure of ''Eucalyptus'' leaves from the Kalgoorlie region of Western Australia that would have been untraceable using other methods. The microscopic leaf-bound "nuggets", about 8 [[micrometre]]s wide on average, are not worth collecting themselves, but may provide an environmentally benign way of locating subsurface mineral deposits.<ref>{{Cite web|url=https://newatlas.com/eucalyptus-gold-leaf-csiro/29520/|title="Gold leaf" trees discovered in the Australian outback|date=2013-10-23|website=newatlas.com|language=en}}</ref><ref>{{Cite web|url=https://news.nationalgeographic.com/news/2013/10/131022-gold-eucalyptus-leaves-mining-geology-science/|archive-url=https://web.archive.org/web/20131023141717/http://news.nationalgeographic.com/news/2013/10/131022-gold-eucalyptus-leaves-mining-geology-science/|url-status=dead|archive-date=October 23, 2013|title=Gold Grows On Eucalyptus Trees|date=2013-10-23|website=National Geographic News|access-date=2019-03-29}}</ref>

==''Eucalyptus'' as plantation species==

In the 20th century, scientists around the world experimented with ''Eucalyptus'' species. They hoped to grow them in the tropics, but most experimental results failed until breakthroughs in the 1960s-1980s in species selection, silviculture, and breeding programs "unlocked" the potential of eucalypts in the tropics. Prior to then, as Brett Bennett noted in a 2010 article, eucalypts were something of the "[[El Dorado]]" of forestry. Today, ''Eucalyptus'' is the most widely planted type of tree in plantations around the world,<ref>Bennett (2010)</ref> in [[South America]] (mainly in [[Brazil]], [[Argentina]], [[Paraguay]] and [[Uruguay]]), [[South Africa]], [[Australia]], [[India]], [[Galicia, Spain|Galicia]], [[Portugal]] and many more.<ref name=gitmap>{{cite web|title=Global Eucalyptus Map 2009... in Buenos Aires!|url=http://git-forestry-blog.blogspot.com/2009/10/global-eucalyptus-map-2009-in-buenos.html|work=GIT Forestry Eucalyptologics|access-date=22 November 2013}}</ref>

===North America===
;California
In the 1850s, ''Eucalyptus'' trees were introduced to [[California]] by Australians during the [[California Gold Rush]]. Much of California is similar in climate to parts of Australia. By the early 1900s, thousands of acres of eucalypts were planted with the encouragement of the state government. It was hoped that they would provide a renewable source of timber for construction, furniture making and [[railway sleeper]]s. It was soon found that for the latter purpose ''Eucalyptus'' was particularly unsuitable, as the ties made from ''Eucalyptus'' had a tendency to twist while drying, and the dried ties were so tough that it was nearly impossible to hammer [[Rail fastening system|rail spikes]] into them.<ref name="Santos" />

<blockquote>They went on to note that the promise of ''Eucalyptus'' in California was based on the old virgin forests of Australia. This was a mistake, as the young trees being harvested in California could not compare in quality to the centuries-old ''Eucalyptus'' timber of Australia. It reacted differently to harvest. The older trees didn't split or warp as the infant California crop did. There was a vast difference between the two, and this would doom the California ''Eucalyptus'' industry.<ref name="Santos">{{cite web |last1=Santos |first1=Robert L. |title=''The Eucalyptus of California - Seeds of good or seeds of evil?'' |url=https://library.csustan.edu/ld.php?content_id=55856157 |publisher=University Library - Stanislaus State |access-date=31 March 2021}}</ref></blockquote>

[[File:Howard-Ralston Eucalyptus Tree Rows.jpg|thumb|upright|The Howard-Ralston Eucalyptus Tree Rows, planted in [[Burlingame, California]], in the 1870s, are listed on the [[National Register of Historic Places]].]]
The species ''[[Eucalyptus camaldulensis|E. camaldulensis]], [[Eucalyptus tereticornis|E. tereticornis]],'' and ''[[Eucalyptus cladocalyx|E. cladocalyx]]'' are all present in California, but the blue gum ''[[Eucalyptus globulus|E. globulus]]'' makes up by far the largest population in the state.<ref>{{Cite web|url=https://books.google.com/books?id=EVIzzgEACAAJ|title=Growth of Eucalyptus in California Plantations|first=Woodbridge|last=Metcalf|date=Oct 1, 1924|publisher=University of California Print. Office|accessdate=Oct 1, 2022|via=Google Books}}</ref> One way in which the ''Eucalyptus'', mainly the blue gum ''[[Eucalyptus globulus|E. globulus]]'', proved valuable in California was in providing windbreaks for highways, orange groves, and farms in the mostly treeless [[Central Valley (California)|central part of the state]]. They are also admired as shade and ornamental trees in many cities and gardens.{{cn|date=June 2024}}

''Eucalyptus'' plantations in California have been criticised, because they compete with native plants and typically do not support native animals. ''Eucalyptus'' has historically been planted to replace California's [[Quercus agrifolia|coast live oak]] population, and the new ''Eucalyptus'' is not as hospitable to native flora and fauna as the oaks. In appropriately foggy conditions on the California Coast, ''Eucalyptus'' can spread at a rapid rate. The absence of natural inhibitors such as the [[koala]] or pathogens native to Australia have aided in the spread of California ''Eucalyptus'' trees. This is not as big of an issue further inland, but on the coast invasive eucalypts can disrupt native ecosystems. ''Eucalyptus'' may have adverse effects on local streams due to their chemical composition, and their dominance threatens species that rely on native trees. Nevertheless, some native species have been known to adapt to the ''Eucalyptus'' trees. Notable examples are [[heron]]s, [[great horned owl]], and the [[monarch butterfly]] using ''Eucalyptus'' groves as habitat. Despite these successes, eucalypts generally has a net negative impact on the overall balance of the native ecosystem.<ref name=":1" />

A heavy concern regarding Eucalypts in California is their status as a fire hazard.<ref>{{Cite news |date=2006 |title=Fire Management Newsletter: Eucalyptus: A Complex Challenge |url=https://home.nps.gov/pore/learn/nature/upload/firemanagement_fireeducation_newsletter_eucalyptus.pdf |access-date=Oct 29, 2024 |work=U.S. National Park Service}}</ref> ''Eucalyptus'' trees were a catalyst for the spread of the [[1923 Berkeley, California fire|1923 fire]] in Berkeley, which destroyed 568 homes.<ref name=":1">{{Cite web|last=Liza|first=Gross|date=June 12, 2013|title=Eucalyptus: California Icon, Fire Hazard and Invasive Species|url=https://www.kqed.org/science/4209/eucalyptus-california-icon-fire-hazard-and-invasive-species#:~:text=The%20California%20Invasive%20Plant%20Council,need%20certain%20conditions%20to%20thrive.&text=Once%20established%2C%20the%20trees%20can,mineralization%20rates%20and%20soil%20chemistry.|website=KQED}}</ref> The 1991 [[Oakland firestorm of 1991|Oakland Hills firestorm]], which caused US$1.5 billion in damage, destroyed almost 3,000 homes, and killed 25 people, was partly fueled by large numbers of eucalypts close to the houses.<ref>{{cite web |last=Williams |first=Ted |title=America's Largest Weed |publisher=Audubon Magazine |date=January 2002 |url=http://magazine.audubon.org/incite/incite0201.html |url-status=dead |archive-url=https://web.archive.org/web/20060708221528/http://magazine.audubon.org/incite/incite0201.html |archive-date=2006-07-08 }}</ref>

Despite these issues, there are calls to preserve the ''Eucalyptus'' plants in California. Advocates for the tree claim its fire risk has been overstated. Some even claim that the ''Eucalyptus's'' absorption of moisture makes it a barrier against fire. These experts believe that the herbicides used to remove the ''Eucalyptus'' would negatively impact the ecosystem, and the loss of the trees would release carbon into the atmosphere unnecessarily. There is also an aesthetic argument for keeping the ''Eucalyptus''; the trees are viewed by many as an attractive and iconic part of the California landscape. Many say that although the tree is not native, it has been in California long enough to become an essential part of the ecosystem and therefore should not be attacked as invasive. These arguments have caused experts and citizens in California, especially in the [[San Francisco Bay Area]], to debate the merits of ''Eucalyptus'' removal versus preservation. However, the general consensus remains that some areas urgently require ''Eucalyptus'' management to stave off potential fire hazards.<ref name=":0">{{Cite web|last=Emma|first=Marris|date=November 30, 2016|title=The Great Eucalyptus Debate|url=https://www.theatlantic.com/science/archive/2016/11/the-great-eucalyptus-debate/509069/|website=The Atlantic}}</ref>

Efforts to remove some of California's ''Eucalyptus'' trees have been met with a mixed reaction from the public, and there have been protests against removal.<ref name=":0" /> Removing ''Eucalyptus'' trees can be expensive and often requires machinery or the use of herbicides. The trees struggle to reproduce on their own outside of the foggy regions of Coastal California, and therefore some inland ''Eucalyptus'' forests are predicted to die out naturally.<ref>{{Cite web|last=Daniel|first=Potter|date=February 1, 2018|title=Eucalyptus: How California's Most Hated Tree Took Root|url=https://www.kqed.org/news/11644927/eucalyptus-how-californias-most-hated-tree-took-root-2|website=KQED}}</ref> In some parts of California, eucalypt plantations are being removed and native trees and plants restored. Individuals have also illegally destroyed some trees and are suspected of introducing insect pests from Australia which attack the trees.<ref name="Henter2005">{{cite web |title=Tree Wars: The Secret Life of Eucalyptus |first=Heather |last=Henter |date=January 2005 |publisher=University of California, San Diego |work=Alumni |url=http://alumni.ucsd.edu/magazine/vol2no1/features/wars.htm|access-date=2013-11-23 |archive-url=https://web.archive.org/web/20090317055602/http://alumni.ucsd.edu/magazine/vol2no1/features/wars.htm |archive-date=2009-03-17 |url-status=dead}}</ref>

Certain ''Eucalyptus'' species may also be grown for ornament in warmer parts of the Pacific Northwest—western [[Washington (state)|Washington]], western [[Oregon]] and southwestern [[British Columbia]].{{cn|date=June 2024}}

===South America===
;Argentina
It was introduced in Argentina around 1870 by President [[Domingo F. Sarmiento]], who had brought the seeds from Australia and it quickly became very popular. The most widely planted species were ''[[Eucalyptus globulus|E. globulus]]'', ''[[Eucalyptus viminalis|E. viminalis]]'' and ''[[Eucalyptus rostrata (disambiguation)|E. rostrata]]''. Currently, the [[Humid Pampas]] region has small forests and ''Eucalyptus'' barriers, some up to 80 years old, about 50 meters high and a maximum of one meter in diameter.<ref>{{Cite web|url=https://carlosfelice.com.ar/blog/2014/11/el-eucalipto-arbol-fundamental-en-el-campo-argentino/|title=El eucalipto, árbol fundamental en el campo argentino|access-date=Sep 11, 2020}}</ref>

;Uruguay
[[Antonio Lussich]] introduced ''Eucalyptus'' into [[Uruguay]] in approximately 1896, throughout what is now [[Maldonado Department]], and it has spread all over the south-eastern and eastern coast. There had been no trees in the area because it consisted of dry sand dunes and stones. Lussich also introduced many other trees, particularly ''[[Acacia]]'' and [[pine]]s, but they have not expanded so extensively.{{cn|date=June 2024}}

Uruguayan forestry crops using ''Eucalyptus'' species have been promoted since 1989, when the new National Forestry Law established that 20% of the national territory would be dedicated to forestry. As the main landscape of Uruguay is grassland (140,000&nbsp;km<sup>2</sup>, 87% of the national territory), most of the forestry plantations would be established in prairie regions.<ref>MGAP, 1999. Uruguay Forestal: antecedentes, legislacion y política, desarrollo actual y perspectives. Ministerio de Agricultura y Pesca,
Montevideo, Uruguay.</ref><ref name="Ribeiro_1999">{{Cite web |url=http://www4.fao.org/cgi-bin/faobib.exe?rec_id=540374&database=faobib&search_type=link&table=mona&back_path=%2Ffaobib%2Fmona&lang=eng&format_name=EFMON |title=J., Ribeiro, C.M., 1999. Tendencias y perspectivas de la economı ́a forestal de los países del Conosur (&#91;&#91;Argentina&#93;&#93;, &#91;&#91;Brasil&#93;&#93;, &#91;&#91;Chile&#93;&#93;, Uruguay). Oficina Regional FAO para America Latina y el Caribe, Santiago, Chile. |access-date=2019-12-11 |archive-url=https://web.archive.org/web/20030927134020/http://www4.fao.org/cgi-bin/faobib.exe?rec_id=540374&database=faobib&search_type=link&table=mona&back_path=%2Ffaobib%2Fmona&lang=eng&format_name=EFMON |archive-date=2003-09-27 |url-status=dead }}</ref><ref name="Perez-Arrarte_1993">Perez-Arrarte, C., 1993. Desarrollo forestal y medio ambiente (compilation). [[Centro Interdisciplinario de Estudios sobre el Desarrollo en Uruguay|CIEDUR]] Montevideo, Uruguay</ref>
The planting of ''Eucalyptus'' sp. has been criticised because of concerns that soil would be degraded by [[nutrient depletion]] and other biological changes.<ref name="Ribeiro_1999" /><ref name="Perez-Arrarte_1993" /><ref name="Caffera_1991">Caffera, R.M., Cespedes, C., Gonzalez, A., Gutierrez, M.O., Panario, D.H., 1991. Hacia una evaluacion de effectos ambientales de la forestacion en Uruguay con especies introducidas. CIEDUR, Montevideo, Uruguay.</ref> During the last ten years, in the northwestern regions of Uruguay the ''Eucalyptus'' sp. plantations have reached annual forestation rates of 300%. That zone has a potential forested area of 1&nbsp;million hectares, approximately 29% of the national territory dedicated to forestry, of which approximately 800,000 hectares are currently forested by monoculture of ''Eucalyptus'' spp.<ref>[http://www.mgap.gub.uy DIEA, 2010. Anuario Estadístico Agropecuario 2010. Dirección de Estadísticas Agropecuarias, Ministerio de Agricultura, Ganadería y Pesca. Editorial Hemisferio Sur, Montevideo, Uruguay, 220p.].</ref> It is expected that the radical and durable substitution of vegetation cover leads to changes in the quantity and quality of [[soil organic matter]]. Such changes may also influence [[soil fertility]] and soil physical and chemical properties. The [[soil quality]] effects associated with ''Eucalyptus'' sp. plantations could have adverse effects on soil chemistry;<ref name="Caffera_1991" /><ref name="AgganganO'Connell1999">{{cite journal|last1=Aggangan|first1=R.T.|last2=o'Connell |first2=A.M.|last3=McGrath |first3=J.F.|last4=Dell |first4=B.|title=The effects of ''Eucalyptus globulus'' Labill. leaf letter on C and N mineralization in soils from pasture and native forest|journal=Soil Biology and Biochemistry|volume=31|issue=11 |year=1999|pages=1481–7|issn=0038-0717|doi=10.1016/S0038-0717(99)00052-8|bibcode=1999SBiBi..31.1481A }}</ref><ref name="GriersonAdams2000">{{cite journal|last1=Grierson|first1=P.F|last2=Adams|first2=M.A|title=Plant species affect acid phosphatase, ergosterol and microbial P in a Jarrah (''Eucalyptus marginata'' Donn ex Sm.) forest in south-western Australia|journal=Soil Biology and Biochemistry|volume=32|issue=13 |year=2000|pages=1817–27 |issn=0038-0717 |doi=10.1016/S0038-0717(00)00155-3|bibcode=2000SBiBi..32.1817G }}</ref> for example: soil acidification,<ref>Bandzouzi, J., 1993. Variabilite spatiale de quelques caracteristiques edaphiques des sols sableux sous ''Eucalyptus'' du littoral congolais. Memoire I.D.R., Universite de Rennes, France.</ref><ref name="Bernhard-Reversat1999">{{cite journal|last1=Bernhard-Reversat|first1=France|title=The leaching of ''Eucalyptus'' hybrids and ''Acacia auriculiformis'' leaf litter: laboratory experiments on early decomposition and ecological implications in congolese tree plantations|journal=Applied Soil Ecology|volume=12|issue=3|year=1999|pages=251–261|issn=0929-1393|doi=10.1016/S0929-1393(99)00005-0|bibcode=1999AppSE..12..251B }}</ref><ref>{{Cite web|url=http://www.befac.net/index.php?choix=200&page_courante=109&x_3=-1&e_p=-1&tpr_pk=1519&c_s=xxxiii&lim_c_q_a=4480&c_q_a=8&m_a_m_i=0%7CLoubelo,|title=澳门华都官网-澳门华都娱乐场-澳门华都赌场|website=www.befac.net|access-date=Sep 11, 2020|archive-date=December 1, 2020|archive-url=https://web.archive.org/web/20201201211642/http://www.befac.net/index.php?choix=200&page_courante=109&x_3=-1&e_p=-1&tpr_pk=1519&c_s=xxxiii&lim_c_q_a=4480&c_q_a=8&m_a_m_i=0%7CLoubelo,|url-status=dead}}</ref> iron leaching, [[allelopathic]] activities<ref name="Bernhard-Reversat1999" /> and a high C:N ratio of litter.<ref name="AgganganO'Connell1999" /><ref>{{cite journal |first=P.K. |last=Khanna |title=Evaluating various indices for measuring N and P status of forest stand with examples from pine and eucalypt sites |journal=Interciencia |volume=19 |pages=366–373 |date=1994 |issn=0378-1844 }}</ref><ref name="MadeiraAndreaux1989">{{cite journal|last1=Madeira|first1=M.A.V.|last2=Andreaux|first2=F.|last3=Portal|first3=J.M.|title=Changes in soil organic matter characteristics due to reforestation with ''Eucalyptus globulus'', in Portugal|journal=Science of the Total Environment|volume=81–82|year=1989|pages=481–8|issn=0048-9697|doi=10.1016/0048-9697(89)90157-5|bibcode=1989ScTEn..81..481M}}</ref><ref>{{cite book |first=M.A.V. |last=Madeira |chapter=Influence of Mineral Nutrients Redistribution in Eucalyptus Plantations on Soil Properties |chapter-url= |editor-last=Berthelin |editor-first=J. |title=Diversity of Environmental Biogeochemistry |series=Development in Geochemistry |publisher=Elsevier |volume=6 |date=1992 |isbn=978-0-444-88900-3 |pages=485–494 |doi=10.1016/B978-0-444-88900-3.50052-7}}</ref> Additionally, as most scientific understanding of land cover change effects is related to ecosystems where forests were replaced by grasslands or crops, or grassland was replaced by crops, the environmental effects of the current Uruguayan land cover changes are not well understood.<ref name="AltesorDi Landro1998">{{cite journal|last1=Altesor|first1=A.|last2=Di Landro|first2=E.|last3=May|first3=H.|last4=Ezcurra|first4=E.|title=Long-term species change in a Uruguayan grassland|journal=Journal of Vegetation Science|volume=9|issue=2 |year=1998|pages=173–180 |issn=1100-9233|doi=10.2307/3237116|jstor=3237116|bibcode=1998JVegS...9..173A }}</ref> The first scientific publication on soil studies in western zone tree plantations (focused on pulp production) appeared in 2004 and described soil acidification and [[soil carbon]] changes,<ref name="Carrasco-LetelierEguren2004">{{cite journal|last1=Carrasco-Letelier|first1=L.|last2=Eguren |first2=G.|last3=Castiñeira |first3=C.|last4=Parra |first4=O.|last5=Panario|first5=D.|title=Preliminary study of prairies forested with ''Eucalyptus'' sp. at the northwestern Uruguayan soils|journal=Environmental Pollution|volume=127 |issue=1|year=2004|pages=49–55 |issn=0269-7491|doi=10.1016/S0269-7491(03)00258-6|pmid=14553994|bibcode=2004EPoll.127...49C }}</ref> similar to a [[podzolisation]] process, and destruction of clay (illite-like minerals), which is the main reservoir of potassium in the soil.<ref name="Céspedes-PayretPiñeiro2012">{{cite journal|last1=Céspedes-Payret|first1=Carlos|last2=Piñeiro |first2=Gustavo|last3=Gutiérrez|first3=Ofelia|last4=Panario |first4=Daniel|title=Land use change in a temperate grassland soil: Afforestation effects on chemical properties and their ecological and mineralogical implications|journal=Science of the Total Environment|volume=438 |year=2012|pages=549–557 |issn=0048-9697|doi=10.1016/j.scitotenv.2012.08.075|pmid=23064181|bibcode=2012ScTEn.438..549C}}</ref> Although these studies were carried out in an important zone for forest cultivation, they cannot define the current situation in the rest of the land area under eucalyptus cultivation. Moreover, recently Jackson and Jobbagy have proposed another adverse environmental impact that may result from ''Eucalyptus'' culture on prairie soils—stream acidification.<ref name="FarleyPiñeiro2008">{{cite journal|last1=Farley|first1=Kathleen A.|last2=Piñeiro|first2=Gervasio|last3=Palmer|first3=Sheila M.|last4=Jobbágy|first4=Esteban G.|last5=Jackson|first5=Robert B.|s2cid=53526927|title=Stream acidification and base cation losses with grassland afforestation|journal=Water Resources Research|volume=44|year=2008|issn=0043-1397|doi=10.1029/2007WR006659|issue=7 |bibcode=2008WRR....44.0A03F|hdl=11336/135148|hdl-access=free}}</ref>

The ''Eucalyptus'' species most planted are ''E. grandis'', ''E. globulus'' and ''E. dunnii''; they are used mainly for pulp mills. Approximately 80,000 ha of ''E. grandis'' situated in the departments of Rivera, Tacuarembó and Paysandú is primarily earmarked for the solid wood market, although a portion of it is used for sawlogs and plywood. The current area under commercial forest plantation is 6% of the total. The main uses of the wood produced are elemental chlorine free pulp mill production (for [[cellulose]] and [[paper]]), [[sawlog]]s, [[plywood]] and [[bioenergy]] ([[thermoelectric]] generation). Most of the products obtained from [[sawmill]]s and [[pulp mill]]s, as well as plywood and [[Trunk (botany)|logs]], are exported. This has raised the income of this sector with respect to traditional products from other sectors. Uruguayan forestry plantations have rates of growth of 30 cubic metres per hectare per year and commercial harvesting occurs after nine years.{{cn|date=June 2024}}

;Brazil

[[File:Plantação de Eucalipto, Parque do Itaim - Taubaté.jpg|thumb|260x260px|A c. 13-year-old plantation, in [[Taubaté]], [[São Paulo (state)|São Paulo]]]]

Eucalypts were introduced to [[Brazil]] in 1910, for [[timber]] substitution and the [[charcoal]] industry. It has thrived in the local environment, and today there are around 7&nbsp;million hectares planted. The wood is highly valued by the charcoal and pulp and paper industries. The short rotation allows a larger wood production and supplies wood for several other activities, helping to preserve the native forests from logging. When well managed, the plantation soils can sustain endless replanting. ''Eucalyptus'' plantings are also used as [[windbreak|wind breaks]]. Brazil's plantations have world-record rates of growth, typically over 40 cubic metres per hectare per year,<ref name="Brazil">{{cite web|url=http://lamar.colostate.edu/~binkley/Brazileucalyptus.htm|title=Brazil Eucalyptus Potential Productivity|publisher=Colorado State University|url-status=dead|archive-url=https://archive.today/20121212024604/http://lamar.colostate.edu/~binkley/Brazileucalyptus.htm|archive-date=2012-12-12}}</ref> and commercial harvesting occurs after years 5. Due to continual development and governmental funding, year-on-year growth is consistently being improved. ''Eucalyptus'' can produce up to 100 cubic metres per hectare per year. Brazil has become the top exporter and producer of ''Eucalyptus'' round wood and pulp, and has played an important role in developing the Australian market through the country's{{Clarify|date=May 2009}} committed research in this area. The local iron producers in Brazil rely heavily on sustainably grown ''Eucalyptus'' for [[charcoal]]; this has greatly pushed up the price of charcoal in recent years. The plantations are generally owned and operated for national and international industry by timber asset companies such as [[Thomson Forestry]], Greenwood Management or cellulose producers such as [[Aracruz Cellulose]] and [[Stora Enso]].{{Citation needed|date=September 2017}}

Overall, South America was expected to produce 55% of the world's ''Eucalyptus'' round-wood by 2010. Many environmental NGOs have criticised the use of exotic tree species for forestry in Latin America.<ref>An example of a poster from a campaign against ''Eucalyptus'' culture is [http://www.redes.org.uy/wp-content/uploads/2012/07/Banner-Forestales-RIO-OK-.pdf here.]</ref>

===Africa===
;Angola
In the East of Angola, the [[Benguela railway]] company created eucalyptus plantations for firing its steam locomotives.{{cn|date=June 2024}}

;Ethiopia
Eucalypts were introduced to [[Ethiopia]] in either 1894 or 1895, either by Emperor [[Menelik II of Ethiopia|Menelik II]]'s French advisor [[Mondon-Vidailhet]] or by the Englishman Captain O'Brian. Menelik II endorsed its planting around his new capital city of [[Addis Ababa]] because of the massive [[deforestation]] around the city for [[firewood]]. According to Richard R.K. Pankhurst, "The great advantage of the eucalypts was that they were fast growing, required little attention and when cut down grew up again from the roots; it could be harvested every ten years. The tree proved successful from the onset".<ref>{{harvnb|Pankhurst|1968|p=246}}</ref> Plantations of eucalypts spread from the capital to other growing urban centres such as [[Debre Marqos]]. Pankhurst reports that the most common species found in Addis Ababa in the mid-1960s was ''[[Eucalyptus globulus|E. globulus]]'', although he also found ''[[Eucalyptus melliodora|E. melliodora]]'' and ''[[Eucalyptus rostrata (disambiguation)|E. rostrata]]'' in significant numbers. David Buxton, writing of central Ethiopia in the mid-1940s, observed that eucalyptus trees "have become an integral -- and a pleasing -- element in the [[Shewa|Shoan]] landscape and has largely displaced the slow-growing native 'cedar' (''[[Juniperus procera]]'')."<ref>{{cite book |first=David |last=Buxton |title=Travels in Ethiopia |edition=2nd |publisher=Benn |year=1957 |oclc=3105137 |page=48}}</ref>

It was commonly believed that the thirst of the ''Eucalyptus'' "tended to dry up rivers and wells", creating such opposition to the species that in 1913 a proclamation was issued ordering a partial destruction of all standing trees, and their replacement with [[Morus (plant)|mulberry]] trees. Pankhurst reports, "The proclamation however remained a dead letter; there is no evidence of eucalypts being uprooted, still less of mulberry trees being planted."<ref>{{harvnb|Pankhurst|1968|p=247}}</ref> Eucalypts remain a defining feature of Addis Ababa.

;Madagascar
Much of Madagascar's original native forest has been replaced with ''Eucalyptus'', threatening biodiversity by isolating remaining natural areas such as [[Andasibe-Mantadia National Park]].{{cn|date=June 2024}}

;South Africa
Numerous ''Eucalyptus'' species have been introduced into [[South Africa]], mainly for [[timber]] and [[firewood]] but also for ornamental purposes. They are popular with [[beekeeper]]s for the [[honey]] they provide.<ref name="palgrave">{{cite book |last1=Palgrave |first1=K.C. |first2=R.B. |last2=Drummond |first3=E.J. |last3=Moll |first4=M.C. |last4=Palgrave |date=2002 |title=Trees of Southern Africa |publisher=Struik Publishers |isbn=9781868723898 |oclc=51494099}}</ref> However, in South Africa they are considered invasive, with their water-sucking capabilities threatening water supplies. They also release a chemical into the surrounding soil which kills native competitors.<ref name="invasive">{{cite web |first=D. |last=Robertson |title=South Africa Water Project Clears Water-Guzzling Alien Plant Infestations |date=2005-03-22|url=http://www.voanews.com/english/archive/2005-03/2005-03-22-voa19.cfm |access-date=2013-11-22 |archive-url=https://web.archive.org/web/20090115005010/http://www.voanews.com/english/archive/2005-03/2005-03-22-voa19.cfm |archive-date=2009-01-15 |url-status=dead}}</ref>

''Eucalyptus'' [[seedling]]s are usually unable to compete with the indigenous [[grass]]es, but after a fire when the grass cover has been removed, a seed-bed may be created. The following ''Eucalyptus'' species have been able to become naturalised in South Africa: ''[[Eucalyptus camaldulensis|E. camaldulensis]]'', ''[[Eucalyptus cladocalyx|E. cladocalyx]]'', ''[[Eucalyptus diversicolor|E. diversicolor]]'', ''[[Eucalyptus grandis|E. grandis]]'' and ''[[Eucalyptus lehmannii|E. lehmannii]]''.<ref name="palgrave" />

;Zimbabwe
As in South Africa, many ''Eucalyptus'' species have been introduced into [[Zimbabwe]], mainly for timber and firewood, and ''[[Eucalyptus robusta|E. robusta]]'' and ''[[Eucalyptus tereticornis|E. tereticornis]]'' have been recorded as having become naturalised there.<ref name="palgrave" />

===Europe===
====Portugal====
Eucalypts have been grown in Portugal since the mid 19th century, the first thought to be a specimen of ''[[Eucalyptus obliqua|E. obliqua]]'' introduced to [[Vila Nova de Gaia]] in 1829.<ref>{{cite web |title=Qual a origem do eucalipto e como chegou a Portugal? |url=https://florestas.pt/saiba-mais/qual-a-origem-do-eucalipto-e-como-chegou-a-portugal/ |publisher=florestas.pt |access-date=5 March 2021}}</ref> First as an ornamental but soon after in [[plantation]]s, these eucalypts are prized due to their long and upright trunks, rapid growth and the ability to regrow after cutting. These plantations now occupy around 800,000 hectares, 10% of the country's total land area, 90% of the trees being ''[[Eucalyptus globulus|E. globulus]]''. As of the late 20th century, there were an estimated 120 species of ''Eucalyptus'' in Portugal.<ref>{{cite web |title=Floresta industrial - Silvicultura do eucalipto em Portugal |url=https://www.e-globulus.pt/biblioteca-online/dossiers/silvicultura-eucalipto-portugal |publisher=e-globulus.pt |access-date=5 March 2021}}</ref> The genus has also been subject to various controversies. Despite representing a large part of the agricultural economy, eucalypt plantations have a negative impact on soil destruction, inducing resistance to water infiltration and increasing the risks of erosion and soil loss, they are highly flammable, aggravating the risk for wildfires. Various Portuguese laws on eucalypt plantations have been formed and reformed to better suit both sides.<ref>{{cite web |last1=Marques |first1=José Trincão |title=A expansão descontrolada do eucalipto em Portugal: "E pur si muove" |date=11 September 2018 |url=https://www.mediotejo.net/a-expansao-descontrolada-do-eucalipto-em-portugal-e-pur-si-muove-por-jose-trincao-marques/ |publisher=mediotejo.net |access-date=5 March 2021}}</ref>

There are various ''Eucalyptus'' species of public interest in Portugal, namely a [[Karri]] in [[Coimbra]]'s Mata Nacional de Vale de Canas, considered to be Europe's tallest tree at {{convert|72|m|ft|abbr=on}} high.<ref>{{cite web |title=Árvores Monumentais de Portugal |url=http://www2.icnf.pt/portal/florestas/aip/aip-monum-pt |publisher=[[ICNF]] |access-date=5 March 2021 |archive-date=9 January 2015 |archive-url=https://web.archive.org/web/20150109230442/http://www2.icnf.pt/portal/florestas/aip/aip-monum-pt |url-status=dead }}</ref><ref>{{cite web |title=Eucaliptos de interesse público: um roteiro em Portugal |date=10 July 2020 |url=https://myplanet.pt/artigos/eucaliptos-de-interesse-publico/ |publisher=myplanet.pt |access-date=5 March 2021}}</ref>

====Italy====
In [[Italy]], the ''Eucalyptus'' only arrived at the turn of the 19th century and large scale plantations were started at the beginning of the 20th century with the aim of drying up swampy ground to defeat malaria.<ref>{{Cite web |title=Italian Health Tip: Eucalyptus Branches in Shower |url=http://www.grandvoyageitaly.com/1/post/2015/10/italian-health-tip-eucalyptus-branches-in-shower.html |access-date=2024-05-29 |website=GRAND VOYAGE ITALY |language=en}}</ref> During the 1930s, [[Benito Mussolini]] had thousands of ''Eucalyptus'' planted in the marshes around Rome.<ref>{{Cite web|url=https://www.timesofmalta.com/articles/view/20130911/environment/The-eucalyptus-tree.485697|title=The eucalyptus tree|last=Portelli|first=Paul|date=September 11, 2013|website=timesofmalta.com|access-date=October 21, 2018}}</ref> This, their rapid growth in the Italian climate and excellent function as windbreaks, has made them a common sight in the south of the country, including the islands of [[Sardinia]] and [[Sicily]].<ref>{{Cite web|title=The Seasonality of Honey|url=https://gustiblog.gustiamo.com/the-seasonality-of-honey/|access-date=28 July 2020|website=Gustiblog|date=9 November 2016 }}</ref> They are also valued for the characteristic smelling and tasting [[honey]] that is produced from them.<ref>{{Cite book|date=2010-06-01|title=Lives of the trees: an uncommon history}}</ref> The variety of ''Eucalyptus'' most commonly found in Italy is ''[[Eucalyptus camaldulensis|E. camaldulensis]]''.<ref>{{cite web|url=http://www.europaoggi.it/content/view/791/114/|title=Europa Oggi - Italia terra da miele|first=Gianni|last=Martino}}</ref>

====Greece====
In [[Greece]], eucalypts are widely found, especially in southern Greece and [[Crete]]. They are cultivated and used for various purposes, including as an ingredient in pharmaceutical products (e.g., creams, elixirs and sprays) and for leather production. They were imported in 1862 by botanist Theodoros Georgios Orphanides. The principal species is ''E. globulus''.<ref>{{Cite journal |last1=Khan |first1=Naushad |last2=Fahad |first2=Shah |last3=Faisal |first3=Shah |last4=Akbar |first4=Ayasha |last5=Naushad |first5=Mahnoor |date=2020-07-06 |title=Socio-Economic and Medicinal Review of Eucalyptus Tree in the World |url=https://papers.ssrn.com/abstract=3644215 |journal=SSRN |location=Rochester, NY |doi=10.2139/ssrn.3644215|ssrn=3644215 |s2cid=233757310 }}</ref>

====Ireland====
''Eucalyptus'' has been grown in Ireland since trials in the 1930s and now grows wild in South Western Ireland in the mild climate.<ref>{{cite web|url=https://www.brc.ac.uk/plantatlas/plant/eucalyptus-globulus|title=''Eucalyptus globulus''|website=brc.ac.uk|year=1973|publisher=John Murray|access-date=2021-12-19|archive-date=2021-12-19|archive-url=https://web.archive.org/web/20211219202146/https://www.brc.ac.uk/plantatlas/plant/eucalyptus-globulus|url-status=dead}}</ref>

===Asia===
''Eucalyptus'' seeds of the species ''E. globulus'' were imported into [[Palestine (region)|Palestine]] in the 1860s, but did not acclimatise well.<ref name="Shemesh">{{cite journal|author=Abraham O. Shemesh |title=Planting eucalyptus trees in the new settlements In nineteenth- to twentieth-century Palestine as reflected in rabbinic documents |journal=Modern Judaism |year=2016 |volume=36 |number=1 |pages=83–99|doi=10.1093/mj/kjv038|s2cid=170476555 }}</ref> Later, ''E. camaldulensis'' was introduced more successfully and it is still a very common tree in [[Israel]].<ref name="Shemesh" /> The use of ''Eucalyptus'' trees to drain swampy land was a common practice in the late nineteenth and early twentieth centuries.<ref name="Shemesh" /><ref name="ElEini" /> The German Templer colony of [[Sarona (colony)|Sarona]] had begun planting ''Eucalyptus'' for this purpose by 1874, though it is not known where the seeds came from.<ref>{{cite book |first1=Helmut |last1=Glenk |first2=Horst |last2=Blaich |first3=Manfred |last3=Haering |title=From Desert Sands to Golden Oranges: The History of the German Templer Settlement of Sarona in Palestine 1871-1947 |publisher=Trafford Publishing |date=2005 |isbn=978-1-4120-3506-4 |pages=6 |url={{GBurl|tr-Z3uCI5DEC|dq=Eucalyptus|pg=PR49}}}}</ref> Many Zionist colonies also adopted the practice in the following years under the guidance of the [[Mikveh Israel|Mikveh Israel Agricultural School]].<ref name="Shemesh" /><ref name="ElEini">{{cite journal |author=Roza I. M. El-Eini |title=British forestry policy in Mandate Palestine, 1929–48: Aims and realities |journal=Middle Eastern Studies |year=1999 |volume=35 |issue=3 |pages=72–155|doi=10.1080/00263209908701280 }}</ref> ''Eucalyptus'' trees are now considered an [[invasive species]] in the region.

In India, the [[ICFRE#Research Institutes under the Council|Institute of Forest Genetics and Tree Breeding, Coimbatore]] started a ''Eucalyptus'' breeding program in the 1990s. The organisation released four varieties of conventionally bred, high yielding and genetically improved clones for commercial and research interests in 2010.<ref name="ifgtb">{{cite news|title=Union Minister announces Rs. 25-crore fund for IFGTB|url=http://www.thehindu.com/todays-paper/tp-national/tp-tamilnadu/union-minister-announces-rs-25crore-fund-for-ifgtb/article713273.ece|access-date=21 November 2013|newspaper=[[The Hindu]]|date=19 February 2010}}</ref><ref name="tnieifgtb">{{cite news|title=Let scientists decide what is good for us|url=http://newindianexpress.com/states/tamil_nadu/article213505.ece|archive-url=https://web.archive.org/web/20131202222924/http://newindianexpress.com/states/tamil_nadu/article213505.ece|url-status=dead|archive-date=December 2, 2013|access-date=21 November 2013|newspaper=[[The New Indian Express]]|date=21 November 2013}}</ref><ref>{{cite web|title=Van Vigyan Newslatter|url=http://ifgtb.icfre.gov.in/pdf_files/enewsletter_jan_mar_2010.pdf|work=Institute of Forest Genetics and Tree Breeding|access-date=21 November 2013|page=2|date=January–March 2010|url-status=dead|archive-url=https://web.archive.org/web/20131202223924/http://ifgtb.icfre.gov.in/pdf_files/enewsletter_jan_mar_2010.pdf|archive-date=2 December 2013}}</ref>

''Eucalyptus'' trees were introduced to [[Sri Lanka]] in the late 19th century by [[tea]] and [[coffee]] planters, for wind protection, shade and fuel. Forestry replanting of ''Eucalyptus'' began in the 1930s in deforested mountain areas, and currently there are about 10 species present in the island. They account for 20% of major reforestation plantings. They provide [[railway sleeper]]s, [[utility pole]]s, sawn [[timber]] and [[fuelwood]], but are controversial because of their adverse effect on biodiversity, hydrology and soil fertility. They are associated with another invasive species, the [[Gall wasp|eucalyptus gall wasp]], ''[[Leptocybe]] invasa''.<ref>{{Cite web|url=http://www.fao.org/3/AC772E/ac772e0l.htm|title=Eucalyptus Plantations in Sri Lanka: Environmental, Social, Economic and Policy Issues - H.M. Bandaratillake|website=www.fao.org|access-date=Sep 11, 2020}}</ref><ref>{{Cite web|url=http://www.sundaytimes.lk/100627/Plus/plus_01.html|title=Another pest, another tree|access-date=Sep 11, 2020}}</ref>

===Pacific Islands===
In [[Hawaii]], some 90 species of ''Eucalyptus'' have been introduced to the islands, where they have displaced some native species due to their higher maximum height, fast growth and lower water needs. Particularly noticeable is the rainbow eucalyptus (''[[Eucalyptus deglupta]]''), native to Indonesia and the Philippines, whose bark falls off to reveal a trunk that can be green, red, orange, yellow, pink and purple.<ref>{{Cite web|url=https://www.to-hawaii.com/trees/eucalyptus.php|title=Eucalyptus Tree|website=www.to-hawaii.com|access-date=Sep 11, 2020}}</ref>

==Non-native ''Eucalyptus'' and biodiversity==
Due to similar favourable climatic conditions, ''Eucalyptus'' plantations have often replaced [[oak]] woodlands, for example in California, Spain and Portugal. The resulting monocultures have raised concerns about loss of biological diversity, through loss of [[acorn]]s that [[mammal]]s and birds feed on, absence of hollows that in oak trees provide shelter and nesting sites for birds and small mammals and for bee colonies, as well as lack of downed trees in managed plantations. A study of the relationship between birds and ''Eucalyptus'' in the San Francisco Bay Area found that bird diversity was similar in native forest versus ''Eucalyptus'' forest, but the species were different.<ref>{{cite journal |title=Equal diversity in disparate species assemblages: a comparison of native and exotic woodlands in California |author=Sax, Dov F. |year=2002 |journal=Global Ecology and Biogeography |pages=49–57 |doi=10.1046/j.1466-822X.2001.00262.x |volume=11 |issue=1 |bibcode=2002GloEB..11...49S |doi-access=free }}</ref> One way in which the avifauna (local assortment of bird species) changes is that cavity-nesting birds including woodpeckers, owls, chickadees, wood ducks, etc. are [[depauperate]] in ''Eucalyptus'' groves because the decay-resistant wood of these trees prevents cavity formation by decay or excavation. Also, those bird species that glean insects from foliage, such as warblers and vireos, experience population declines when ''Eucalyptus'' groves replace oak forest.{{cn|date=June 2024}}

Birds that thrive in ''Eucalyptus'' groves in California tend to prefer tall vertical habitat. These avian species include herons and egrets, which also nest in redwoods.<ref>{{cite report |title=Birds and Eucalyptus on the Central California Coast: A Love-Hate Relationship |author=David L. Suddjian |publisher=David Suddian Biological Consulting |date=2004-06-03 |url=http://www.elkhornsloughctp.org/uploads/1108147180Suddjian-unpublished%20conference%20notes.pdf |access-date=2013-11-22 |archive-url=https://web.archive.org/web/20120326062119/http://www.elkhornsloughctp.org/uploads/1108147180Suddjian-unpublished%20conference%20notes.pdf |archive-date=2012-03-26 |url-status=dead}}</ref><ref name="Kelly1993">{{cite journal|last1=Kelly|first1=J.P.|last2=Pratt|first2=H.M.|last3=Greene|first3=P.L.|title=The Distribution, Reproductive Success, and Habitat Characteristics of Heron and Egret Breeding Colonies in the San Francisco Bay Area|journal=Colonial Waterbirds |volume=16|issue=1|year=1993|pages=18–27|doi=10.2307/1521552 |jstor=1521552}}</ref> The [[Point Reyes Bird Observatory]] observes that sometimes short-billed birds like the [[ruby-crowned kinglet]] are found dead beneath ''Eucalyptus'' trees with their nostrils clogged with pitch.<ref name="NPS" />

[[Monarch (butterfly)|Monarch]] butterflies use ''Eucalyptus'' in California for overwintering, but in some locations have a preference for [[Monterey pine]]s.<ref name="NPS" />

=== ''Eucalyptus'' as an invasive species ===
''Eucalyptus'' trees are considered invasive to local ecosystems and negatively impact water resources in countries where they are introduced.<ref name="invasive" />

'''South Africa'''

In South Africa, ''Eucalyptus'' tree species ''E. camaldulensis'', ''E. cladocalyx'', ''E.'' ''conferruminata,'' ''E. diversicolor'', ''E. grandis'' and ''E. tereticornis'' are listed as Category 1b invaders in the [[National Environmental Management Act, 1998|National Environmental Management]]: Biodiversity Act. This means most activities with regards to the species are prohibited (such as importing, propagating, translocating or trading) and it should be ensured that it does not spread beyond a plantation's domain.<ref>{{Cite journal |title=South African Government Gazette: Number 37320 |url=https://archive.gazettes.africa/archive/za/2014/za-government-gazette-dated-2014-02-12-no-37320.pdf |journal=[[Government Gazette of South Africa]] |volume=584 |pages=28}}</ref>

''E. cladocalyx'' and ''E. diversicolor'' are considered [[Fynbos]] invaders,<ref>{{Citation |last1=Le Maitre |first1=David C. |title=Impacts of Plant Invasions on Terrestrial Water Flows in South Africa |date=2020 |work=Biological Invasions in South Africa |pages=431–457 |editor-last=van Wilgen |editor-first=Brian W. |series=Invading Nature - Springer Series in Invasion Ecology |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-32394-3_15 |isbn=978-3-030-32394-3 |last2=Blignaut |first2=James N. |last3=Clulow |first3=Alistair |last4=Dzikiti |first4=Sebinasi |last5=Everson |first5=Colin S. |last6=Görgens |first6=André H. M. |last7=Gush |first7=Mark B. |s2cid=216398000 |editor2-last=Measey |editor2-first=John |editor3-last=Richardson |editor3-first=David M. |editor4-last=Wilson |editor4-first=John R.|doi-access=free }}</ref> and use up to 20% more water than the native fynbos vegetation; with invasive species including ''Eucalyptus'' being cleared that reduce Cape Town's water resource by 55 billion litres or two months worth of water supply.<ref>{{Cite web|url=https://www.nature.org/content/dam/tnc/nature/en/documents/GCTWF-Business-Case_2018-11-14_Web.pdf|title=THE GREATER CAPE TOWN WATER FUND - ASSESSING THE RETURN ON INVESTMENT FOR ECOLOGICAL INFRASTRUCTURE RESTORATION}}</ref><ref>{{Cite web |last=Coles |first=Wayne |date=2020-01-21 |title=Eucalyptus - the 'thirsty' trees threatening to 'drink' South Africa dry |url=https://blog.invasive-species.org/2020/01/21/eucalyptus-the-thirsty-trees-threatening-to-drink-south-africa-dry/ |access-date=2023-09-09 |website=Invasive Species Blog |language=en-GB}}</ref>

==Photo album==
<gallery>
<!-- Please only add pictures where the species or variety of tree has been identified and the location — there are many varieties of eucalyptus and it is not encyclopaedic to say merely "eucalyptus"-->
File:Eucalyptus macarthurii UC.jpg|Mature ''[[Eucalyptus macarthurii]]'', at the [[University of Canterbury]]
File:E.sideroxylon, branchlets, stems, leaves, capsules & buds.jpg|''[[Eucalyptus sideroxylon]]'', showing fruit (capsules) and buds with [[Operculum (botany)|operculum]] present.
File:Bach dan.jpg|''Eucalyptus'' forest in [[Shire of East Gippsland|East Gippsland]], [[Victoria (Australia)|Victoria]]. Mostly ''E. albens'' (white box).
File:Applebox.JPG|''[[Eucalyptus bridgesiana|E. bridgesiana]]'' (apple box) on [[Red Hill, Australian Capital Territory]].
File:euc.uk.600pix.jpg|''[[Eucalyptus gunnii|E. gunnii]]'' planted in southern [[England]]. The lower part of the trunk is covered in [[ivy]].
File:Eucalyptus cinera x pulverulenta.jpg|''[[Eucalyptus cinerea]]'' x ''[[Eucalyptus pulverulenta|pulverulenta]]'' - National Botanical Gardens Canberra
File:Eucalyptus gall.jpg|''Eucalyptus'' gall
File:CPonte Eucalyptus.jpg|''[[Eucalyptus grandis|E. grandis]]''. Province of [[Buenos Aires]], [[Argentina]].
File:Eucalipto Galicia.JPG|''Eucalyptus'' plantation near [[Viveiro]], in [[Galicia (Spain)|Galicia]] in Northwest [[Spain]]. Mostly ''E. globulus''
File:Snow Gum1.JPG|A [[snow gum]] (''E. pauciflora''), in winter in the [[Australian Alps]]
File:Eucalyptus rubida.jpg|''[[Eucalyptus rubida|E. rubida]]'' ([[candlebark gum]]) in [[Burra, New South Wales]].
File:Sydney Blue Gums Kippara Forest via Wauchope.JPG|[[Sydney blue gum]]s west of [[Port Macquarie]], New South Wales
File:Eucalyptus Chapmaniana 5198.JPG|''[[Eucalyptus chapmaniana]]'' (bogong gum) in [[Royal Botanic Gardens, Kew|Kew Gardens]], [[London]]
File:Sherbrooke forest Victoria 220rs.jpg|''[[Eucalyptus regnans|E. regnans]]'' trees in [[Sherbrooke Forest]], [[Victoria (Australia)|Victoria]]
File:Dean-Nicolle-Deanei.JPG|''[[Eucalyptus deanei|E. deanei]]'', [[Blue Mountains National Park]], [[Australia]]
File:Prospectcreek.jpg|Eucalypt woodland area near [[Prospect Creek (New South Wales)|Prospect Creek]] in western [[Sydney]]. Mostly ''[[Eucalyptus amplifolia|E. amplifolia]]'' and ''[[Eucalyptus tereticornis|E. tereticornis]]''.
</gallery>

== References ==
{{Reflist}}
{{refbegin}}
* {{cite journal|doi=10.1017/S0020859010000489|title=The El Dorado of Forestry: The Eucalyptus in India, South Africa, and Thailand, 1850–2000|journal=International Review of Social History|volume=55|pages=27–50|year=2010|last1=Bennett|first1=Brett M.|doi-access=free}}
* {{cite book |first=W.F. |last=Blakely |title=A Key to the Eucalypts: with descriptions of 522 species and 150 varieties |publisher=Forest and Timber Bureau |location=Canberra |date=1972 |isbn=978-0-642-95077-2 |oclc=27495079 |edition=reprint (3rd) |orig-year=1965}}
* {{Cite book |last=Boland |first=D.J. |title=Forest Trees of Australia |publisher=CSIRO Publishing |location=Collingwood, Victoria |year=2006|author2=M.I.H. |author3=McDonald |author4=M.W. |author5=Chippendale |author6=G.M. |author7=Hall |author8=N. |author9=Hyland, B.P.M.| author-link9=Bernie Hyland | author10=Kleinig |author11=D.A. |author-link5=George Chippendale |edition=5th |isbn=0-643-06969-0}}
* {{Cite book |last1=Brooker |first1=M.I.H. |last2=Kleinig |first2=D.A. |series=Field Guide to Eucalyptus |publisher=Bloomings |location=Melbourne |year=2006 |edition=3rd |isbn=1-876473-52-5 |volume=1 |title=South-eastern Australia}}
* {{cite book |last1=Kelly |first1=Stan |first2=G.M. |last2=Chippendale |first3=R.D. |last3=Johnston |title=Eucalypts |publisher=Nelson |location=Melbourne |date=1989 |isbn=978-0-670-90178-4 |volume=1 |oclc=27558064 |edition=Revised}}
* {{Cite book |last=L'Héritier de Brutelles |first=C. L. |title=Sertum Anglicum |publisher=Didot |location=Paris |year=1789}}
* {{Cite journal |last1=Myburg |first1=Alexander A. |last2=Grattapaglia |first2=Dario |last3=Tuskan |first3=Gerald A. |last4=Hellsten |first4=Uffe |last5=Hayes |first5=Richard D. |last6=Grimwood |first6=Jane |last7=Jenkins |first7=Jerry |last8=Lindquist |first8=Erika |last9=Tice |first9=Hope |last10=Bauer |first10=Diane |last11=Goodstein |first11=David M. |last12=Dubchak |first12=Inna |last13=Poliakov |first13=Alexandre |last14=Mizrachi |first14=Eshchar |last15=Kullan |first15=Anand R. K. |last16=Hussey |first16=Steven G. |last17=Pinard |first17=Desre |last18=Van Der Merwe |first18=Karen |last19=Singh |first19=Pooja |last20=Van Jaarsveld |first20=Ida |last21=Silva-Junior |first21=Orzenil B. |last22=Togawa |first22=Roberto C. |last23=Pappas |first23=Marilia R. |last24=Faria |first24=Danielle A. |last25=Sansaloni |first25=Carolina P. |last26=Petroli |first26=Cesar D. |last27=Yang |first27=Xiaohan |last28=Ranjan |first28=Priya |last29=Tschaplinski |first29=Timothy J. |last30=Ye |first30=Chu-Yu |display-authors=1 |year=2014 |title=The genome of Eucalyptus grandis |journal=Nature |volume=510 |issue=7505 |pages=356–362 |doi=10.1038/nature13308 |pmid=24919147 |bibcode=2014Natur.510..356M |doi-access=free|hdl=1854/LU-5655667 |hdl-access=free }}
* {{Cite book |last=Pankhurst |first=Richard K. P. |title=Economic History of Ethiopia |location=Addis Ababa |publisher=Haile Selassie I University |year=1968|author-link=Richard Pankhurst (academic) }}
{{refend}}

==External links==
{{commonscat}}
* [http://keyserver.lucidcentral.org:8080/euclid/player.jsp?keyId=2&thumbnails=true Lucid Online Player - EUCLID Eucalypts of Australia] ([[Multi-access key]]) to 917 species/subspecies taxonomy as of December 2009.
* {{cite web |title=''Eucalyptus'', ''Corymbia'' and ''Angophora'' |work=ANPSA Plant Guide |url=https://anpsa.org.au/genera/eucalypts-eucalyptus-corymbia-angophora/}}
* [http://www.dn.com.au/ Currency Creek Arboretum - Eucalypt Research]
* [http://www.eucalyptus.com.br/index_eng.html ''Eucalyptus'' Online Book & Newsletter] by [http://www.celso-foelkel.com.br/english.html Celso Foelkel] (2005-current)
* [http://www.gutenberg.org/files/38937/38937-h/38937-h.htm#Eucalyptus L'Héritier's original diagnosis of the genus online on Project Gutenberg]
* {{cite web |first=James A. |last=Duke |title=Handbook of Energy Crops |date=1983 |publisher= |url=http://www.hort.purdue.edu/newcrop/duke_energy/Eucalyptus.html}}
* [http://library.csustan.edu/sites/default/files/Bob_Santos-The_Eucalyptus_of_California.pdf ''The Eucalyptus of California: Seeds of Good or Seeds of Evil?''] {{Webarchive|url=https://web.archive.org/web/20190927101659/http://library.csustan.edu/sites/default/files/Bob_Santos-The_Eucalyptus_of_California.pdf |date=2019-09-27 }} Santos, Robert. 1997 Denair, CA : Alley-Cass Publications
* {{cite news |first=Jared |last=Farmer |title=The Rise and Fall of the Gum Tree: How California Came to Love—then Disown—Eucalyptus |newspaper=Zócalo Public Square |date=2014 |publisher= |url=http://www.zocalopublicsquare.org/2014/01/03/the-rise-and-fall-of-the-gum-tree/ideas/nexus/ }}
* [http://git-forestry-blog.blogspot.com/ EUCALYPTOLOGICS: Information Resources on ''Eucalyptus'' cultivation around the World] Iglesias Trabado, Gustavo (2007-current)
* {{cite web |title=''Eucalyptus'' L'Hér. |work=Atlas of Living Australia |url=https://bie.ala.org.au/species/https://id.biodiversity.org.au/taxon/apni/51360942}}

{{Taxonbar|from=Q45669}}
{{Authority control}}

[[Category:Eucalyptus|*]]
[[Category:Taxa described in 1789]]
[[Category:Taxa named by Charles Louis L'Héritier de Brutelle]]
[[Category:Flora of the Australasian realm]]