Eucalyptus robusta

Eucalyptus robusta grows commonly as a straight, upright tree to around {{convert|20|–|30|m|ft|sigfig=1}} tall, with a trunk up to {{convert|1|m|ft|abbr=off}} in diameter at breast height (dbh). The trunk and branches are covered with thick red-brown bark, which has a spongy feel and is stringy—peeling in longitudinal strips. The long irregular branches spread laterally, and form a dense canopy with the broad green leaves. Arranged alternately along the stems, these measure {{convert|10|–|16|cm|in|abbr=off}} long by {{convert|2.7|to|4.5|cm|in|abbr=on}} wide. Adult leaves are broadly lanceolate to ovate, green and glossy, and with closely spaced "feather-like" side veins running at greater than 45° angle to the main midrib.

The white or cream flowers are clustered in inflorescences of from 7 to 13 flowers.{{cite book| author = Boland, D. J. | orig-year = 1984| year=2006 | title = Forest Trees of Australia | edition = 4th | isbn = 0-643-06969-0|publisher=CSIRO Publishing|location=Collingwood, Victoria |page = 298 |url = https://books.google.com/books?id=q2v3kb9tFsYC&q=Eucalyptus+robusta+boland&pg=PA298|display-authors=etal}} The flowers appear anywhere from March to September, and peak over May and June.{{cite journal|last=Benson |first=Doug |author2=McDougall, Lyn |year=1998 |title=Ecology of Sydney plant species:Part 6 Dicotyledon family Myrtaceae |journal=Cunninghamia |volume=5 |issue=4 |page=926 |url=http://www.rbgsyd.nsw.gov.au/__data/assets/pdf_file/0008/58049/Cun5Ben808.pdf |archive-url=http://webarchive.loc.gov/all/20090614173442/http://www.rbgsyd.nsw.gov.au/__data/assets/pdf_file/0008/58049/Cun5Ben808.pdf |url-status=dead |archive-date=2009-06-14}} Retrieved 12-24-2011. The buds measure {{convert|2|by|0.8|cm|in|abbr=on}} wide and are distinctive in that the operculum has a prominent long beak,{{cite book|author1=Fairley, Alan |author2=Moore, Philip |title=Native Plants of the Sydney District: An Identification Guide |year=2000 |edition= 2nd|publisher=Kangaroo Press |page=210|location=Kenthurst, NSW |isbn=0-7318-1031-7}} making them fusiform (spindle-shaped).{{NSW Flora Online|genus=Eucalyptus |species=robusta |author=Hill, Ken}} Retrieved 11 April 2012. The woody fruits are cylindrical-shaped, 1 to 1.6 cm long by 0.7 to 1.1 cm wide, pedicellate with descending disc and 3 to 4 valves at rim level or slightly exserted. Seeds are light-brown to yellow to 1.8mm long, pyramidal or obliquely pyramidal in shape.{{cite web|title=EUCLID - Eucalyptus robusta|url=https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_robusta.htm|website=lucidcentral.org|publisher=Centre for Australian Biodiversity Research|access-date=29 May 2020}}

The bangalay (E. botryoides) is similar in appearance, but its flower buds are smaller with a conical operculum and only grow in groups of seven. The fruits are smaller and sessile, rather than on stalks.

File:Eucalyptus robusta (Sowerby).jpg, from James Edward Smith's 1793 A Specimen of the Botany of New Holland]]

Specimens of E. robusta were first collected by First Fleet surgeon and naturalist John White, and the species description was published by James Edward Smith in his 1793 collaboration with George Shaw, Zoology and Botany of New Holland. Shortly afterwards, the description was reprinted verbatim in Smith's A Specimen of the Botany of New Holland, and it is this publication that is usually credited. Smith gave it the specific epithet robusta ("robust") in reference to the size and strength of the full-grown tree.{{cite book | first = James Edward | last = Smith | author-link = James Edward Smith (botanist) | year = 1793 | title = A Specimen of the Botany of New Holland | location = London | publisher = James Sowerby}} The common name of swamp mahogany comes from its preferred habitat of swamps, and its timber's likeness to that of West Indies mahogany (Swietenia mahagoni). Eucalyptus robusta is known as the swamp messmate in Queensland. Swamp stringybark is another common name,{{cite web | title = Australian Plant Common Name Database | url = http://www.anbg.gov.au/common.names/ | access-date = 15 July 2007 | publisher = Australian National Botanic Gardens}} and Gulgong and Gnorpin are old names recorded. It is called robusta eucalyptus in the United States, beakpod eucalyptus in Puerto Rico,{{citation |title=Robusta Eucalyptus|author1=King, James R. |author2=Skolmen, Roger G. |publisher=USDA Forest Service, Northeastern Area State & Private Forestry}} and mkaratusi in Swahili.

Eucalyptus robusta belongs to a group of eight species of spongy red-barked gum trees known as red mahoganies in the section Annulares, and is closely related to the bangalay and red mahogany (E. resinifera). It is distinguished from them by its larger flowers and fruit. The latter species grows in drier habitats.

Eucalyptus robusta often hybridises with forest red gum (E. tereticornis), the resulting plants having been given the name E. patentinervis. Hybrids reported with other species include bangalay, flooded gum (E. grandis), Tasmanian blue gum (E. globulus), woollybutt (E. longifolia) and Bancroft's red gum (E. bancroftii).{{cite web|title=Eucalyptus robusta|url= https://id.biodiversity.org.au/instance/apni/454508|publisher=APNI|access-date=15 December 2019}}

This species occurs in swamps and alongside estuaries in a narrow coastal strip, usually within a few kilometres of the ocean, from Rockhampton, Queensland south to Jervis Bay, New South Wales. It is also found offshore on Great Keppel, Moreton, Fraser and North and South Stradbroke Islands. It is widely planted as a timber tree, and is considered to be invasive in Hawai{{okina}}i and Réunion,[http://www.hear.org/pier/species/eucalyptus_robusta.htm Pacific Island Ecosystems at Risk (PIER) Species info: Eucalyptus robusta]. Retrieved 2009-11-02. and has become naturalised in Florida. It generally grows on heavy clay soils, but is also found on sandy clay and alluvial sand soils. It grows on sand on offshore islands. Found from sea level to altitudes of {{convert|50|m|ft|abbr=on}} above sea level, it grows in swamps or areas where the water table is high, generally fresh or brackish in nature. Older plants are able to tolerate salt but seedlings cannot. Eucalyptus robusta can also grow in highly acidic sulphate estuarine soils with a pH as low as 2.5. It is a dominant tree in swamp forests, often growing in pure stands or with other trees such as red mahogany (E. resinifera), red bloodwood (Corymbia gummifera), pink bloodwood (Corymbia intermedia), swamp sheoak (Casuarina glauca), snow-in-summer (Melaleuca linariifolia), swamp paperbark (M. ericifolia) and, less commonly, forest red gum (E. tereticornis).

The species has been formally assessed for the IUCN Red List as "Near Threatened (NT)" as its population is thought to have declined by 25.7% over the previous three generations. The species has lost much of its habitat to urbanisation and landclearing for agriculture and much of what is left is highly fragmented.

A long-lived tree, Eucalyptus robusta can live for at least two hundred years. Trees regenerate by regrowing from epicormic buds on the trunk after bushfire. The grey-headed flying fox (Pteropus poliocephalus) eats the flowers, and the koala (Phascalarctos cinereus) eats the leaves. Eucalyptus robusta appears to be one of several key species of eucalypt for the koala in the Shire of Noosa in Queensland.{{Cite journal | last1 = Callaghan | first1 = J. | last2 = McAlpine | first2 = C. | last3 = Mitchell | first3 = D. | last4 = Thompson | first4 = J. | last5 = Bowen | first5 = M. | last6 = Rhodes | first6 = J. | last7 = De Jong | first7 = C. | last8 = Domalewski | first8 = R. | last9 = Scott | first9 = A. | doi = 10.1071/WR07177 | title = Ranking and mapping koala habitat quality for conservation planning on the basis of indirect evidence of tree-species use: A case study of Noosa Shire, south-eastern Queensland | journal = Wildlife Research | volume = 38 | issue = 2 | pages = 89–102 | year = 2011 | bibcode = 2011WildR..38...89C }} The musk lorikeet feeds on the nectar of the blossoms.{{cite book |author1=Barker, Robin Dale |author2=Vestjens, Wilhelmus Jacobus Maria | year = 1984 | title = The Food of Australian Birds: (I) Non-passerines | publisher = Melbourne University Press | isbn = 0-643-05007-8 | url=https://books.google.com/books?id=Fh0RYPeTOz8C&q=%22Eucalyptus+robusta%22&pg=PA348|pages = 347–48}} It is a favoured tree species of the critically endangered swift parrot on the mainland.{{cite journal |last1=Birdlife Australia |title=Swift Parrot Identification Guide |url=https://birdlife.org.au/documents/WL-A_Guide_to_Identifying_the_Critically_Endangered_Swift_Parrot.pdf}} It is a keystone species on the New South Wales Central Coast and Illawarra regions, where it is one of few reliable winter-flowering plants. Stands of E. robusta have been drastically reduced by land clearance. Some remnant trees in Robson Park in the Sydney suburb of Haberfield are the last vestiges of the Sydney Coastal Estuary Swamp Forest Complex community in Sydney's inner western suburbs.{{cite web|url=http://www.ashfield.nsw.gov.au/files/environment/state_of_the_environment/state_of_environment_report_2009-2010.pdf|title=State of the Environment Report 2009–2010|last=Ashfield Council|year=2010|publisher=Ashfield Council|access-date=25 April 2012|archive-date=22 March 2012|archive-url=https://web.archive.org/web/20120322042908/http://www.ashfield.nsw.gov.au/files//environment/state_of_the_environment/state_of_environment_report_2009-2010.pdf|url-status=dead}}

Insects, such as psyllids and Christmas beetles from the genus Anoplognathus and the eucalyptus chafer (Xylonichus eucalypti) commonly eat the leaves. The rectangular-lerp forming psyllid Glycaspis siliciflava eats only this species. The scale insects Brachyscelis munita and Opisthoscelis pisiformis form galls. The adult double drummer cicada (Thopha saccata) lives in the tree, while larvae of the small staghorn beetle species Ceratognathus froggattii and another beetle Moechidius rugosus live and pupate within the thick bark. The wood-moth (Aenetus splendens) makes a thick bag-like structure around a branch where it breeds. The beetle species Maecolaspis favosa attacks the leaves in Florida.

Eucalyptus robusta plantations in Madagascar are host to prolific numbers of mushrooms, some of which are edible and widely consumed. Two species of the genus Russula – Russula prolifica and R. madecassense – and several as yet undescribed species of chanterelle of the genus Cantharellus are sold in markets and eaten. The appearance of R. prolifica is enigmatic, as it has only become abundant in the past seventy years, and is unknown in Australia.{{Cite journal | last1 = Buyck | first1 = Bart| title = The Edible Mushrooms of Madagascar: An Evolving Enigma | doi = 10.1007/s12231-008-9029-4 | journal = Economic Botany | volume = 62 | issue = 3 | pages = 509–20 | year = 2008 | bibcode = 2008EcBot..62..509B| s2cid = 39119949}} Introduced Eucalyptus robusta trees developed ectomycorrhizal associations in the Seychelles, with a high correlation with local tree species Vateriopsis seychellarum and ipil (Intsia bijuga), seemingly gaining these relationships from those species.{{cite book|last=Suvi, Triin|title=Mycorrhizal fungi of native and introduced trees in the Seychelles Islands|publisher=Tartu University Press|year=2010|isbn=978-9949-19-297-7 |url=http://dspace.utlib.ee/dspace/bitstream/handle/10062/14622/suvi_triin.pdf?sequence=1}}

File:Eucalyptus robustarbgsyd2.JPG

Eucalyptus robusta adapts well to cultivation, though it often grows too large for home gardens. It has been used as a street tree, and is useful in public areas with wet soils. It can grow very quickly in cultivation and flower profusely.{{cite book | last1=Elliot | first1=Rodger W. | last2=Jones | first2=David L. | last3=Blake | first3=Trevor |title=Encyclopaedia of Australian Plants Suitable for Cultivation: Vol. 4: Eu-Go |year=1992|page=198 |publisher=Lothian Press |location=Port Melbourne |isbn=0-85091-213-X}} It can flower in its third year of growth in cultivation in optimal conditions, and its timing makes it an important source of food during autumn and winter.{{cite web |title=Swamp Mahogany Tree |url=https://www.northernbeaches.nsw.gov.au/council/environment/tree/swamp-mahogany |website=Environment |date=12 June 2012 |publisher=northern beaches council |access-date=23 May 2021}} Birds are attracted to its flower heads. However, in some years its leaves are infested with lerps and detract from its appearance. A row of E. robusta was planted at the Royal Botanic Gardens, Sydney in 1813, and the trees are still healthy.

A cultivar with variegated leaves, E. robusta "Green and Gold" was commercially available in 2005 in Australia. It is smaller than the wild form, reaching {{convert|5|-|8|m}} in height.{{cite book|last=Burke|first=Don|title=The Complete Burke's Backyard: The Ultimate Book of Fact Sheets|publisher=Murdoch Books|year=2005|pages=338|isbn=1-74045-739-0|url=https://books.google.com/books?id=MMMjW6AuzHAC&q=%22Eucalyptus+robusta%22&pg=PA338}}

Eucalyptus robusta is widely grown from equatorial to temperate regions, tolerating a wide range of climates and conditions. Its fast early growth and tolerance for waterlogging have rendered it a useful tree to grow.{{cite book|last=CABI|title=The CABI Encyclopedia of Forest Trees|publisher=CABI|location=Wallingford Oxfordshire|date=2013|pages=189–91|isbn=9781780642369|url=https://books.google.com/books?id=cBf4AgAAQBAJ&q=%22Eucalyptus+regnans%22+plantations&pg=PA189}} It has been widely grown in plantations outside Australia, including Argentina, Brazil, Cameroon, Chile, China, Colombia, Comoros, Congo, Costa Rica, Democratic Republic of Congo, Ethiopia, Fiji, Honduras, Hong Kong, India, Kenya, Madagascar, Malawi, Malaysia, Mauritius, Mexico, Mozambique, Papua New Guinea, Paraguay, Philippines, Puerto Rico, South Africa, Sri Lanka, Taiwan—Republic of China, Tanzania, Uganda, Zanzibar, and the United States of America,{{cite web|url=http://www.worldagroforestry.org/sea/products/afdbases/af/asp/SpeciesInfo.asp?SpID=809|title=Eucalyptus robusta|last=World Agroforestry Centre|work=AgroForestryTree Database: A tree species reference and selection guide|publisher=PROSEA (Plant Resources of South-East Asia)|access-date=11 April 2012|archive-date=16 April 2013|archive-url=https://archive.today/20130416081329/http://www.worldagroforestry.org/sea/products/afdbases/af/asp/SpeciesInfo.asp?SpID=809|url-status=dead}} where it has been grown in Hawaii, southern Florida, southern California and Puerto Rico. Introduction to Florida took place around 1880, Hawaii around 1885, and Puerto Rico in 1929. The tree is used for firewood and as charcoal in many countries, in erosion control, on sand dunes and as a roadside shade tree in many places, and in Uganda is used to drain swamps. Plantation crops are harvested after 4–5 years for fuel wood, 8–10 years for pulp wood, 15–20 years for poles and 30–60 years for logs for sawing.

In cultivation, E. robusta grows to altitudes of {{convert|1600|m}}, withstanding average minimum temperatures of {{convert|3|C|F}} and maxima of {{convert|35|C|F}}. The heartwood is extremely durable and resists marine borers. It is used as a round timber for construction of wharves and fencing. The wood is light reddish brown in colour and coarse-textured. The weight can vary widely between individuals and stands, averaging 38 pounds per cubic foot.{{cite journal|last=Skolmen|first=Roger G.|year=1972|title=Specific Gravity Variation in Robusta Eucalyptus Grown in Hawaii|journal=USDA Forest Research Paper|issue=78|pages=1–7|url=http://www.fs.fed.us/psw/publications/documents/psw_rp078/psw_rp078.pdf}}

File:Eucalyptus robusta - adult leaves 02.jpg|Adult leaves

File:Eucalyptus robustarbgsyd1.JPG|Buds

File:Eucalyptus robusta - buds 02.jpg|Buds

File:Eucalyptus robusta flowers gosford.jpg|Inflorescence

File:Eucalyptus robusta - flowers.jpg|Flowers

File:Eucalyptus robusta - fruit.jpg|Fruit

File:Eucalyptus robusta - trunk bark.jpg|Trunk bark

File:StepStoolByHenryCaroselli2025.jpg|Finger-jointed Eucalyptus robusta was upcycled from a shipping pallet for use in this attractive step stool.

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• {{Commons category-inline|Eucalyptus robusta|Eucalyptus robusta}}
• {{Wikisource-inline|Portal:Eucalyptus robusta|Eucalyptus robusta}}
• {{Wikisource-inline|A specimen of the botany of New Holland/Eucalyptus robusta|A specimen of the botany of New Holland: Eucalyptus robusta}}

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robusta

Category:Myrtales of Australia

Category:Trees of Australia

Category:Flora of New South Wales

Category:Flora of Queensland

Category:Plants described in 1793

Category:Taxa named by James Edward Smith