''Eucalyptus'' () is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of over seven hundred species of
flowering
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s, shrubs or
mallees in the
myrtle family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
, Myrtaceae. Along with several other genera in the
tribe
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...
Eucalypteae
Eucalypteae is a large tribe of flowering plants in the family Myrtaceae; members of this tribe are known as eucalypts. In Australia the genera ''Angophora'', ''Corymbia'', and ''Eucalyptus'' are commonly known as gum trees, for the sticky substa ...
, including ''
Corymbia'', they are commonly known as
eucalypt
Eucalypt is a descriptive name for woody plants with capsule fruiting bodies belonging to seven closely related genera (of the tribe Eucalypteae) found across Australasia:
''Eucalyptus'', ''Corymbia'', ''Angophora'', '' Stockwellia'', ''Allosyn ...
s. Plants in the genus ''Eucalyptus'' have bark that is either smooth, fibrous, hard or stringy, leaves with oil
glands
In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).
Structure
De ...
, and
sepal
A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...
s and
petal
Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...
s that are fused to form a "cap" or
operculum over the
stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s. The fruit is a woody
capsule commonly referred to as a "gumnut".
Most species of ''Eucalyptus'' are
native
Native may refer to:
People
* Jus soli, citizenship by right of birth
* Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory
** Native Americans (disambiguation)
In arts and entert ...
to Australia, and every state and territory has representative species. About three-quarters of Australian forests are eucalypt forests.
Wildfire
A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...
is a feature of the Australian landscape and many eucalypt species are adapted to fire, and resprout after fire or have seeds which 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 and have valuable timber, or can be used for
pulpwood, for
honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
production or
essential oils. In some countries, however, they have been removed because of the danger of
forest fires due to their high inflammability.
Description
Size and habit
Eucalypts vary in size and
habit
A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously. from shrubs to tall trees. Trees usually have a single main stem or
trunk but many eucalypts are mallees that are multistemmed from ground level and rarely taller than . There is no clear distinction between a mallee and a shrub but in eucalypts, a shrub is a mature plant less than tall and growing in an extreme environment. ''
E. vernicosa'' in the
Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
n highlands, ''
E. yalatensis'' on the
Nullarbor
The Nullarbor Plain ( ; Latin: feminine of , 'no', and , 'tree') is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to its ...
and ''
E. surgens'' growing on coastal cliffs in
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
are examples of eucalypt shrubs.
The terms "
mallet" and "
marlock A marlock or moort is a shrubby or small-tree form of ''Eucalyptus'' found in Western Australia. Unlike the mallee, it is single-stemmed and lacks a lignotuber. It has a dense canopy of leaves which often extends to near ground level.
Marlock spec ...
" are only applied to
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
n eucalypts. A mallet is a tree with a single thin trunk with a steeply branching habit but lacks both a
lignotuber
A lignotuber is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire. Other woody plants may develop basal burls as a similar survival strategy, often as a response t ...
and
epicormic buds
An epicormic shoot is a shoot growing from an epicormic bud, which lies underneath the bark of a trunk, stem, or branch of a plant.
Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up ...
. ''
E. 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. ''
E. platypus'' is an example of a marlock.
''Eucalyptus'' trees, including mallets and marlocks, are single-stemmed and include ''
Eucalyptus regnans
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as euc ...
'', the tallest known flowering plant on Earth.
Tree sizes follow the convention of:
* Small: to in height
* Medium-sized:
* Tall:
* Very tall: over
Tasmania logging 08 Mighty tree.jpg, ''Eucalyptus regnans
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as euc ...
'', a forest tree, showing crown dimension, Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
TocumwalTownBeach.jpg, '' E. camaldulensis'', immature woodland trees, showing collective crown habit, Murray River
The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest r ...
, Tocumwal
Tocumwal ( ) is a town in the southern Riverina region of New South Wales, Australia, in the Berrigan Shire local government area, near the Victorian border. The town is situated on the banks of the Murray River, north of the city of Melbourne ...
, New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
Eucalyptus cretata.jpg, '' E. cretata'', juvenile, showing low branching 'mallee' form, Melbourne
Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...
, Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
Eucalyptus angustissima1.jpg, '' E. angustissima'', showing shrub form, Melbourne
Eucalyptus platypus.jpg, '' E. platypus'', showing ‘marlock’ form, Melbourne
Bark
All eucalypts add a layer of 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 ''
E. sheathiana'', ''
E. diversicolor'', ''
E. cosmophylla'' and ''
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 ''
E. macrorhyncha'' or peppermints such as ''
E. radiata'') or more tightly adherent (as in the "boxes" such as ''
E. leptophleba''). In some species (the "ironbarks" such as ''
E. crebra'' and ''
E. jensenii'') the rough bark is infused with gum resin.
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, ''
E. brachycalyx'', ''
E. ochrophloia'', and ''
E. occidentalis''—or only in a thick, black accumulation at the base, as in ''
E. clelandii''. In some species in this category, for example ''
E. youngiana'' and ''
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 ''
E. deglupta''.
[
'' E. globulus'' bark cells are able to photosynthesize in the absence of foliage, conferring an "increased capacity to re-fix internal CO2 following partial defoliation". 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.
Different commonly recognised types of bark include:
* Stringybark—consists of long fibres and can be pulled off in long pieces. It is usually thick with a spongy texture.
* ]Ironbark
Ironbark is a common name of a number of species in three taxonomic groups within the genus ''Eucalyptus'' that have dark, deeply furrowed bark.
Instead of being shed annually as in many of the other species of ''Eucalyptus'', the dead bark accum ...
—is hard, rough, and deeply furrowed. It is impregnated with dried kino
Kino may refer to:
Arts, entertainment and media Broadcasters
* KINO, a radio station in Arizona, U.S.
* Kino FM (98.0 FM – Moscow), a Russian music radio station
* KinoTV, now Ruutu+ Leffat ja Sarjat, a Finnish TV channel
Fictional entiti ...
(a sap
Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant.
Sap is distinct from latex, resin, or cell sap; it is a separ ...
exuded by the tree) which gives a dark red or even black colour.
* Tessellated—bark is broken up into many distinct flakes. They are 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.
Apple box bark.jpg, Bark detail of '' E. angophoroides'', the apple-topped box
Eucalyptus deglupta-trees.jpg, Coloured bark of '' E. deglupta'' native to Southeast Asia
Eucalyptus bark.jpg, 'Box' bark of '' E. quadrangulata'', the white-topped box
Eucalyptus sideroxylon - bark.jpg, Dark, fissured 'ironbark
Ironbark is a common name of a number of species in three taxonomic groups within the genus ''Eucalyptus'' that have dark, deeply furrowed bark.
Instead of being shed annually as in many of the other species of ''Eucalyptus'', the dead bark accum ...
' of '' E. sideroxylon''
Leaves
Nearly all ''Eucalyptus'' are evergreen
In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...
, but some tropical species lose their leaves at the end of the dry season. As in other members of the 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.
The leaves on a mature ''Eucalyptus'' plant are commonly lanceolate
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...
, petiolate, apparently alternate
Alternative or alternate may refer to:
Arts, entertainment and media
* Alternative (''Kamen Rider''), a character in the Japanese TV series ''Kamen Rider Ryuki''
* ''The Alternative'' (film), a 1978 Australian television film
* ''The Alternative ...
and waxy or glossy green. In contrast, the leaves of seedlings are often opposite, sessile
Sessility, or sessile, may refer to:
* Sessility (motility), organisms which are not able to move about
* Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant
* Sessility (medicine), tumors and polyps that ...
and glaucous, but many exceptions to this pattern exist. Many species such as '' E. melanophloia'' and ''E. setosa'' retain the juvenile leaf form even when the plant is reproductively mature. Some species, such as '' E. macrocarpa'', '' E. rhodantha'', and '' E. crucis'', are sought-after ornamentals due to this lifelong juvenile leaf form. A few species, such as '' E. petraea'', '' E. dundasii'', and '' E. lansdowneana'', have shiny green leaves throughout their life cycle. '' E. 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.
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.[Brooker & Kleinig (2001)]
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 '' 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.
Flowers and fruits
The most readily recognisable characteristics of ''Eucalyptus'' species are the distinctive flowers and fruit (capsules or "gumnuts"). Flowers have numerous fluffy stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s which may be white, cream, yellow, pink, or red; in bud, the stamens are enclosed in a cap known as an 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 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.
Taxonomy
The genus ''Eucalyptus'' was first formally described in 1789 by Charles Louis L'Héritier de Brutelle
Charles Louis L'Héritier de Brutelle (; 15 June 1746 – 18 August 1800) was an 18th-century French botanist and civil servant. Born into an affluent upper-class Parisian family, connections with the French Royal Court secured him the position of ...
who published the description in his book ''Sertum Anglicum, seu, Plantae rariores quae in hortis juxta Londinum'' along with a description of the type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
, ''Eucalyptus obliqua
''Eucalyptus obliqua'', commonly known as messmate stringybark or messmate, but also known as brown top, brown top stringbark, stringybark or Tasmanian oak, is a species of tree that is endemic to south-eastern Australia. It has rough, stringy or ...
''. The name ''Eucalyptus'' is derived from the Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
words meaning 'good, well, true, beautiful, very' and meaning '(I) cover, conceal, hide' referring to the operculum covering the flower buds.
The type specimen was collected in 1777 by David Nelson, the gardener-botanist on Cook's third voyage. He collected the specimen on Bruny Island
Bruny Island ( Nuenonne: Lunawanna-alonnah) is a island located off the south-eastern coast of Tasmania, Australia. The island is separated from the Tasmanian mainland by the D'Entrecasteaux Channel, and its east coast lies within the Tasman ...
and sent it to de Brutelle who was working in London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
at that time.
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
Sir Joseph Banks, 1st Baronet, (19 June 1820) was an English naturalist, botanist, and patron of the natural sciences.
Banks made his name on the 1766 natural-history expedition to Newfoundland and Labrador. He took part in Captain James ...
and Daniel Solander
Daniel Carlsson Solander or Daniel Charles Solander (19 February 1733 – 13 May 1782) was a Swedish naturalist and an apostle of Carl Linnaeus.
Solander was the first university-educated scientist to set foot on Australian soil.
Biography ...
arrived at Botany Bay
Botany Bay (Dharawal: ''Kamay''), an open oceanic embayment, is located in Sydney, New South Wales, Australia, south of the Sydney central business district. Its source is the confluence of the Georges River at Taren Point and the Cook ...
with Captain James Cook
James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean and ...
. There they collected specimens of ''E. gummifera'' and later, near the Endeavour River
The Endeavour River ( Guugu Yimithirr: ''Wabalumbaal''), inclusive of the Endeavour River Right Branch, the Endeavour River South Branch, and the Endeavour River North Branch, is a river system located on Cape York Peninsula in Far North Queens ...
in northern ''Queensland'', ''E. platyphylla''; neither of these species was named as such at the time.
In 1777, on Cook's third expedition, David Nelson collected a eucalypt on Bruny Island
Bruny Island ( Nuenonne: Lunawanna-alonnah) is a island located off the south-eastern coast of Tasmania, Australia. The island is separated from the Tasmanian mainland by the D'Entrecasteaux Channel, and its east coast lies within the Tasman ...
in southern Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
. This specimen was taken to the British Museum
The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...
in London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
, and was named ''Eucalyptus obliqua'' by the French botanist L'Héritier, who was working in London at the time. He coined the generic name from the Greek roots ''eu'' and ''calyptos'', meaning "well" and "covered" in reference to the 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
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
at flowering. It was most likely an accident that L'Héritier chose a feature common to all eucalypts.
The name ''obliqua'' was derived from the Latin ''obliquus'', meaning "oblique", which is the botanical
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...
term describing a leaf
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...
base where the two sides of the leaf blade are of unequal length and do not meet the petiole at the same place.
''E. obliqua'' was published in 1788–89, which coincided with the first official European settlement 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 James Edward Smith may refer to:
* James Edward Smith (botanist), English botanist and founder of the Linnean Society
* James Edward Smith (murderer), American murderer
* James Edward Smith (politician), Canadian businessman and mayor of Toronto
* ...
and most were, as might be expected, trees of the Sydney
Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...
region. These include the economically valuable ''E. pilularis'', ''E. saligna'' and ''E. tereticornis''.
The first endemic Western Australian ''Eucalyptus'' to be collected and subsequently named was the Yate ('' E. cornuta'') by the French botanist Jacques Labillardière
Jacques-Julien Houtou de Labillardière (28 October 1755 – 8 January 1834) was a French biologist noted for his descriptions of the flora of Australia. Labillardière was a member of a voyage in search of the La Pérouse expedition. He pub ...
, who collected in what is now the Esperance area in 1792.[
Several Australian botanists were active during the 19th century, particularly ]Ferdinand von Mueller
Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...
, whose work on ''eucalypts'' contributed greatly to the first comprehensive account of the genus in George Bentham
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studi ...
'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
Joseph Henry Maiden (25 April 1859 – 16 November 1925) was a botanist who made a major contribution to knowledge of the Australian flora, especially the genus ''Eucalyptus''. This botanist is denoted by the author abbreviation when citing ...
(1903–33) and still further by William Faris Blakely
William Faris Blakely (November 1875 – 1 September 1941) was an Australian botanist and collector. From 1913 to 1940 he worked in the National Herbarium of New South Wales, working with Joseph Maiden on ''Eucalyptus'', Maiden named a ''red g ...
(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
Over 700 species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of ''Eucalyptus'' are known. Some have diverged from the mainstream of the genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
to the extent that they are quite isolated genetically
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ...
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
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
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
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
, while others have not diverged completely from their nearest relatives.
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.[
Renantherin, a phenolic compound present in the leaves of some ''Eucalyptus'' species, allows chemotaxonomic discrimination in the sections renantheroideae and renantherae and the ratio of the amount of ]leucoanthocyanin
Leucoanthocyanidin (flavan-3,4-diols) are colorless chemical compounds related to anthocyanidins and anthocyanins. Leucoanthocyanins can be found in ''Anadenanthera peregrina'' and in several species of ''Nepenthes'' including '' N. burbidgeae ...
s varies considerably in certain species.
Related genera
''Eucalyptus'' is one of three similar genera that are commonly referred to as "eucalypt
Eucalypt is a descriptive name for woody plants with capsule fruiting bodies belonging to seven closely related genera (of the tribe Eucalypteae) found across Australasia:
''Eucalyptus'', ''Corymbia'', ''Angophora'', '' Stockwellia'', ''Allosyn ...
s", the others being '' Corymbia'' and '' Angophora''. Many species, though by no means all, are known as gum trees because they exude copious kino
Kino may refer to:
Arts, entertainment and media Broadcasters
* KINO, a radio station in Arizona, U.S.
* Kino FM (98.0 FM – Moscow), a Russian music radio station
* KinoTV, now Ruutu+ Leffat ja Sarjat, a Finnish TV channel
Fictional entiti ...
from any break in the bark (e.g., scribbly gum). The generic name is derived from the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
words ευ (''eu'') "well" and καλύπτω (''kalýpto'') "to cover", referring to the operculum on the calyx that initially conceals the flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
.
Distribution
There are more than 700 species of ''Eucalyptus'' and most are native to Australia; a very small number are found in adjacent areas of New Guinea
New Guinea (; Hiri Motu
Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea).
It is a simplified version of ...
and Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
. One species, ''Eucalyptus deglupta
''Eucalyptus deglupta'' is a species of tall tree, commonly known as the rainbow eucalyptus, Mindanao gum, or rainbow gum that is native to the Philippines, Indonesia, and Papua New Guinea. It is the only ''Eucalyptus'' species that usually liv ...
,'' ranges as far north as the Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
. 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
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
, Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, the Mediterranean Basin
In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and w ...
, the Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, and the Indian subcontinent
The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
. However, the range over which many eucalypts can be planted in the temperate zone is constrained by their limited cold tolerance.
Australia is covered by of eucalypt forest, comprising three quarters of the area covered by native forest. The Blue Mountains of southeastern Australia have been a centre of eucalypt diversification; their name is in reference to the blue haze prevalent in the area, believed derived from the volatile terpenoid
The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes" ...
s emitted by these trees.
Fossil record
The oldest definitive ''Eucalyptus'' fossils are from Patagonia
Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...
in South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, where eucalypts are no longer native, though they have been introduced from Australia. The fossils are from the early Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
(51.9 Mya), and were found in the Laguna del Hunco Formation in Chubut Province
Chubut ( es, Provincia del Chubut, ; cy, Talaith Chubut) is a province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes ra ...
in Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. This shows that the genus had a Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
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.
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
The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
, 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
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
. Other fossils have been found, but many are either unreliably dated or else unreliably identified.[Hill, R. S. "The history of selected Australian taxa." History of the Australian vegetation: Cretaceous to Recent (1994): 390.]
It is useful to consider where ''Eucalyptus'' fossils have not been found. Extensive research has gone into the fossil floras of the Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...
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
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
, eucalypts were displaced to the continental margins, and much of the mesic and rainforest vegetation that was once there was eliminated entirely.
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.
Tall timber
Several eucalypt species are among the tallest trees in the world. ''Eucalyptus regnans
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as euc ...
'', the Australian 'mountain ash', is the tallest of all flowering plants (angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s); today, the tallest measured specimen named Centurion
A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 ...
is tall. Coast Douglas-fir
''Pseudotsuga menziesii'' var. ''menziesii'', commonly known as Coast Douglas-fir, Pacific Douglas-fir, Oregon pine, or Douglas spruce, is an evergreen conifer native to western North America from west-central British Columbia, Canada southward t ...
is about the same height; only coast redwood
''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995:606–607 is the sole living species of the genus '' Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast redwood, coastal ...
is taller, and they are conifers (gymnosperm
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνό ...
s). Six other eucalypt species exceed 80 metres in height: ''Eucalyptus obliqua
''Eucalyptus obliqua'', commonly known as messmate stringybark or messmate, but also known as brown top, brown top stringbark, stringybark or Tasmanian oak, is a species of tree that is endemic to south-eastern Australia. It has rough, stringy or ...
'', ''Eucalyptus delegatensis
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...
'', ''Eucalyptus diversicolor
''Eucalyptus diversicolor'', commonly known as karri, is a species of flowering plant in the family Myrtaceae and is endemic to the south-west of Western Australia. It is a tall tree with smooth light grey to cream-coloured, often mottled bark ...
'', ''Eucalyptus nitens
''Eucalyptus nitens'', commonly known as shining gum or silvertop, is a species of tall tree native to Victoria and eastern New South Wales. It has smooth greyish bark, sometimes with thin, rough bark near the base, lance-shaped adult leaves, flo ...
'', ''Eucalyptus globulus
''Eucalyptus globulus'', commonly known as southern blue gum or blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. This ''Eucalyptus'' species has mostly smooth bark, juvenile leaves that are whitish and waxy on ...
'' and ''Eucalyptus viminalis
''Eucalyptus viminalis'', commonly known as the manna gum, white gum or ribbon gum, is a species of small to very tall tree that is endemic to south-eastern Australia. It has smooth bark, sometimes with rough bark near the base, lance-shaped to c ...
''.
Frost intolerance
Most eucalypts are not tolerant of severe cold. Eucalypts do well in a range of climates but are usually damaged by anything beyond a light frost of ; the hardiest are the snow gums, such as ''Eucalyptus pauciflora
''Eucalyptus pauciflora'', commonly known as snow gum, cabbage gum or white sally, is a species of tree or mallee that is native to eastern Australia. It has smooth bark, lance-shaped to elliptical leaves, flower buds in clusters of between sev ...
'', which is capable of withstanding cold and frost down to about . 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
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
such as ''Eucalyptus coccifera
''Eucalyptus coccifera'', commonly known as the Tasmanian snow gum, is a small to medium-sized tree endemic to Tasmania. It has smooth, grey and cream-coloured bark, elliptic to lance-shaped adult leaves, flower buds in groups of between three a ...
'', '' Eucalyptus subcrenulata'' and ''Eucalyptus gunnii
''Eucalyptus gunnii'', commonly known as cider gum, is a species of small to medium-sized tree endemic to the island of Tasmania, Australia. It has mostly smooth bark, lance-shaped to egg-shaped adult leaves, flower buds in groups of three, whi ...
'', have also produced extreme cold-hardy forms and it is seed procured from these genetically
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ...
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 herbivores, notably koala
The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the w ...
s and some possums
Possum may refer to:
Animals
* Phalangeriformes, or possums, any of a number of arboreal marsupial species native to Australia, New Guinea, and Sulawesi
** Common brushtail possum (''Trichosurus vulpecula''), a common possum in Australian urban a ...
, are relatively tolerant of it. The close correlation of these oils with other more potent toxins called formylated phloroglucinol
Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isomers are hydroxyqu ...
compounds ( euglobals, macrocarpals and sideroxylonals) allows koalas and other marsupial
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...
species to make food choices based on the smell of the leaves. For koalas, these compounds are the most important factor in leaf choice.
''Eucalyptus'' flowers produce a great abundance of nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
, providing food for many pollinators including insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s, birds, bats
Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bir ...
and possums
Possum may refer to:
Animals
* Phalangeriformes, or possums, any of a number of arboreal marsupial species native to Australia, New Guinea, and Sulawesi
** Common brushtail possum (''Trichosurus vulpecula''), a common possum in Australian urban a ...
. Many lizard species in Australia feed on ''Eucalyptus'' sap as well, famously in the case of the Dubious dtella
Dubious dtella, the native Australian house gecko, or dubious four-clawed gecko (''Gehyra dubia'') is a species of gecko in the genus '' Gehyra'', native to Northeastern Australia (Queensland and northern New South Wales as well as islands of the ...
. Although ''Eucalyptus'' trees are seemingly well-defended from herbivores by the oils and phenolic compounds, they have insect pests. These include the eucalyptus longhorn borer '' Phoracantha semipunctata'' and the aphid-like psyllid
Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants ...
s that create "bell lerps", both of which have become established as pests throughout the world wherever eucalypts are cultivated.
The eusocial
Eusociality (from Greek εὖ ''eu'' "good" and social), the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping gen ...
beetle ''Austroplatypus incompertus
''Austroplatypus incompertus'' is a species of ambrosia beetle belonging to the true weevil family, native to Australia, with a verified distribution in New South Wales and Victoria. It forms colonies in the heartwood of ''Eucalyptus'' trees and ...
'' makes and defends its galleries exclusively inside ''Eucalyptus'' plants.
The trunks and branches of the ''Eucalyptus'' tree allow the largest known moth, ''Zelotypia stacyi'' (the bentwing ghost moth, having a wingspan up to 250 mm) to feed and protect their larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
and pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...
, respectively.
Adaptation to fire
Eucalypts originated between 35 and 50 million years ago, not long after Australia-New Guinea
The continent of Australia, sometimes known in technical contexts by the names Sahul (), Australia-New Guinea, Australinea, Meganesia, or Papualand to distinguish it from the country of Australia, is located within the Southern and East ...
separated from Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
, 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 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
''Casuarina'' is a genus of 17 tree species in the family Casuarinaceae, native to Australia, the Indian subcontinent, southeast Asia, islands of the western Pacific Ocean, and eastern Africa. It was once treated as the sole genus in the fami ...
'' and ''Acacia
''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...
'' species.
The two valuable timber trees, alpine ash '' E. delegatensis'' and Australian mountain ash '' E. regnans'', are killed by fire and only regenerate from seed. The same 2003 bushfire that had little impact on forests around Canberra
Canberra ( )
is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...
resulted in thousands of hectares of dead ash forests. However, a small amount of ash survived and put out new ash trees as well.
Fire hazard
''Eucalyptus'' oil is highly flammable; ignited trees have been known to explode. Bushfires
A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identif ...
can travel easily through the oil-rich air of the tree crowns. Eucalypts obtain long-term fire survivability from their ability to regenerate from epicormic buds
An epicormic shoot is a shoot growing from an epicormic bud, which lies underneath the bark of a trunk, stem, or branch of a plant.
Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up ...
situated deep within their thick bark, or from lignotuber
A lignotuber is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire. Other woody plants may develop basal burls as a similar survival strategy, often as a response t ...
s,[ or by producing ]serotinous
Serotiny in botany simply means 'following' or 'later'.
In the case of serotinous flowers, it means flowers which grow following the growth of leaves, or even more simply, flowering later in the season than is customary with allied species. Havi ...
fruits.
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.[Reid, J.B. & Potts, B.M. (2005). Eucalypt Biology. In: Reid ''et al.'' (eds.) Vegetation of Tasmania., pp. 198-223. Australian Government.] 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. It has been estimated that 70% of the energy released through the combustion of vegetation in the Oakland fire was due to ''Eucalyptus''. 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.[
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.”
]
Falling branches
Some species of ''Eucalyptus'' drop branches unexpectedly. In Australia, Parks Victoria warns campers not to camp under Eucalyptus camaldulensis, river red gums. 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. A former Australian National Botanic Gardens director and consulting arborist, Robert Boden, has been quoted referring to "summer branch drop". 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 due to its high resin content, increasing the hazard.
Cultivation and uses
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
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
, South Asia and South America. About 250 species are under cultivation in California. 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 corridors and rotations management.
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[WorldWatch Institute. (2007) ''State of the World (book series), State of the World: Our Urban Future''.] and the Peruvian Andes,[Luzar J. (2007). The Political Ecology of a "Forest Transition": Eucalyptus forestry in the Southern Peruvian. ''Ethnobotany Research & Applications''.] despite concerns that the trees are Invasive species, invasive in some environments like those of South Africa.[ 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. Eucaplytus 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 biofuels. Fast growth also makes eucalypts suitable as windbreaks and to reduce erosion.
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 swamps 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][ and criticised for being "water-guzzling" Invasive species, aliens,][ leading to controversy over their total impact.][
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, elsewhere in ]Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, in the Caucasus (Western Georgia (country), Georgia), and California. Drainage removes swamps which provide a habitat for mosquito larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
e, but can also destroy ecologically productive areas. This drainage is not limited to the soil surface, because the ''Eucalyptus'' roots are up to in length and can, depending on the location, even reach the phreatic zone.
Pulpwood
''Eucalyptus'' is the most common short fibre source for pulpwood to make Pulp (paper), pulp. The types most often used in papermaking are ''Eucalyptus globulus
''Eucalyptus globulus'', commonly known as southern blue gum or blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. This ''Eucalyptus'' species has mostly smooth bark, juvenile leaves that are whitish and waxy on ...
'' (in temperate areas) and the ''Eucalyptus urophylla'' x ''Eucalyptus grandis'' hybrid (in the tropics). 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 papers. The low coarseness is important for high quality coated papers. ''Eucalyptus'' is suitable for many tissue papers as the short and slender fibres gives a high number of fibres per gram and low coarseness contributes to softness.
''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, and serves as an active ingredient in some commercial mosquito-repellents. Aromatherapy, Aromatherapists have adopted ''Eucalyptus'' oils for a wide range of purposes. ''Eucalyptus globulus
''Eucalyptus globulus'', commonly known as southern blue gum or blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. This ''Eucalyptus'' species has mostly smooth bark, juvenile leaves that are whitish and waxy on ...
'' is the principal source of ''Eucalyptus'' oil worldwide.
Musical instruments
Eucalypt wood is also commonly used to make didgeridoos, a traditional Australian Aboriginals, Australian Aboriginal wind instrument. The trunk of the tree is hollowed out by termites, and then cut down if the bore is of the correct size and shape.
Dyes
All parts of ''Eucalyptus'' may be used to make dyes 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. The material remaining after processing can be safely used as mulch or fertiliser.
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 micrometres wide on average, are not worth collecting themselves, but may provide an environmentally benign way of locating subsurface mineral deposits.
''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, in South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
(mainly in Brazil, Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
, Paraguay and Uruguay), South Africa, Australia, India, Galicia, Spain, Galicia, Portugal and many more.
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 sleepers. 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.
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.
The species ''Eucalyptus camaldulensis, Eucalyptus rostrata, Eucalyptus tereticornis, E. tereticornas,'' and '' E. cladocalyx'' are all present in California, but the blue gum '' E. globulus'' makes up by far the largest population in the state. One way in which the ''Eucalyptus'', mainly the blue gum '' 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.
''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
The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the w ...
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 herons, 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.
Fire is also a problem. Eucalypts has been noted for their flammable properties and the large fuel loads in the understory of eucalypt forests. ''Eucalyptus'' trees were a catalyst for the spread of the 1923 Berkeley, California fire, 1923 fire in Berkeley, which destroyed 568 homes. 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.
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 ''Eucalypti'' 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 and the San Francisco Bay Area, 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.
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. 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. 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.
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.
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 '' E. globulus'', '' 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.
;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
''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...
'' and pines, but they have not expanded so extensively.
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 km2, 87% of the national territory), most of the forestry plantations would be established in prairie regions.[Perez-Arrarte, C., 1993. Desarrollo forestal y medio ambiente (compilation). Centro Interdisciplinario de Estudios sobre el Desarrollo en Uruguay, CIEDUR Montevideo, Uruguay]
The planting of ''Eucalyptus'' sp. has been criticised because of concerns that soil would be degraded by nutrient depletion and other biological changes.[Caffera, R.M., Cespedes, C., Gonzalez, A., Gutierrez, M.O., Panario, D.H., 1991. Hacia una evaluacion de efectos ambientales de la forestacion en Uruguay con especies introducidas. CIEDUR, Montevideo, Uruguay.] 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 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. 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; for example: soil acidification, iron leaching, allelopathic activities and a high C:N ratio of litter. 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. 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, similar to a podzolisation process, and destruction of clay (illite-like minerals), which is the main reservoir of potassium in the soil. 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.
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), sawlogs, plywood and bioenergy (thermoelectric generation). Most of the products obtained from sawmills and pulp mills, 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.
;Brazil
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 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, 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 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.
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.
Africa
;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". 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 '' 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'')."
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." 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.
;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 beekeepers for the honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
they provide.[Palgrave, K. C. 2002: ''Trees of Southern Africa''. Struik Publishers, Cape Town.] 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.
''Eucalyptus'' seedlings are usually unable to compete with the indigenous grasses, 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: '' E. camaldulensis'', '' E. cladocalyx'', '' E. diversicolor'', ''Eucalyptus grandis, E. grandis'' and ''Eucalyptus lehmannii, E. lehmannii''.[
;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.][
]
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. First as an ornamental but soon after in plantations, 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 '' E. globulus''. As of the late 20th century, there were an estimated 120 species of ''Eucalyptus'' in Portugal. 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 inflamable, aggravating the risk for wildfires. Various Portuguese laws on eucalypt plantations have been formed and reformed to better suit both sides.
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 high.
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. During the 1930s, Benito Mussolini had thousands of ''Eucalyptus'' planted in the marshes around Rome. 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. They are also valued for the characteristic smelling and tasting honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
that is produced from them. The variety of ''Eucalyptus'' most commonly found in Italy is '' E. camaldulensis''.
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 ''Eucalyptus globulus''.
Ireland
''Eucalyptus'' has been grown in Ireland since trials in the 1930s and now grows wild in South Western Ireland in the mild climate.
Asia
''Eucalyptus'' seeds of the species ''E. globulus'' were imported into Palestine (region), Palestine in the 1860s, but did not acclimatise well. Later, ''E. camaldulensis'' was introduced more successfully and it is still a very common tree in Israel.[ The use of ''Eucalyptus'' trees to drain swampy land was a common practice in the late nineteenth and early twentieth centuries.][ 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. Many Zionist colonies also adopted the practice in the following years under the guidance of the Mikveh Israel, Mikveh Israel Agricultural School.] ''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.
''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 sleepers, utility poles, 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''.
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
''Eucalyptus deglupta'' is a species of tall tree, commonly known as the rainbow eucalyptus, Mindanao gum, or rainbow gum that is native to the Philippines, Indonesia, and Papua New Guinea. It is the only ''Eucalyptus'' species that usually liv ...
''), native to Indonesia and the Philippines, whose bark falls off to reveal a trunk that can be green, red, orange, yellow, pink and purple.
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 acorns that mammals 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. 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.
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. 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.[
Monarch (butterfly), Monarch butterflies use ''Eucalyptus'' in California for over-wintering, but in some locations have a preference for Monterey pines.][
]
Photo album
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 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
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
.
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 gums west of Port Macquarie, New South Wales
File:Eucalyptus Chapmaniana 5198.JPG, ''Eucalyptus chapmaniana'' (bogong gum) in Royal Botanic Gardens, Kew, Kew Gardens, London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
File:Sherbrooke forest Victoria 220rs.jpg, '' 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
Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...
. Mostly ''Eucalyptus amplifolia, E. amplifolia'' and ''Eucalyptus tereticornis, E. tereticornis''.
References
General source
*
* Blakely, W.F., ''A Key to the Eucalypts: with descriptions of 522 species and 150 varieties''. Third Edition, 1965, Forest and Timber Bureau, Canberra.
* 5th edition.
* Third edition. vol. 1. ''South-eastern Australia''.
* Kelly, Stan, text by G. M. Chippendale and R. D. Johnston, ''Eucalypts: Volume I''. Nelson, Melbourne 1969, 1982, etc.
*
*
*
External links
Lucid Online Player - EUCLID Eucalypts of Australia
(Multi-access key) to 917 species/subspecies taxonomy as of December 2009.
ANPSA Plant Guide: ''Eucalyptus'', ''Corymbia'' and ''Angophora''
Currency Creek Arboretum - Eucalypt Research
b
(2005-current)
* [http://www.hort.purdue.edu/newcrop/duke_energy/Eucalyptus.html Handbook of Energy Crops] Duke, James A. 1983.
''The Eucalyptus of California: Seeds of Good or Seeds of Evil?''
Santos, Robert. 1997 Denair, CA : Alley-Cass Publications
"The Rise and Fall of the Gum Tree: How California Came to Love—then Disown—Eucalyptus"
Farmer, Jared. 2014.
EUCALYPTOLOGICS: Information Resources on ''Eucalyptus'' cultivation around the World
Iglesias Trabado, Gustavo (2007-current)
{{Authority control
Eucalyptus, *
Taxa described in 1789
Taxa named by Charles Louis L'Héritier de Brutelle
Australasian realm flora