Eucalyptus globulus

Eucalyptus globulus
E. globulus in Hawaii
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Myrtales
Family: Myrtaceae
Genus: Eucalyptus
Species: E. globulus
Binomial name
Eucalyptus globulus
Labill.

Eucalyptus globulus, the Tasmanian bluegum,[1] southern blue-gum[2] or blue gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30–55 m (98–180 ft) tall. The tallest currently known specimen in Tasmania is 90.7 m (298 ft) tall.[3] There are historical claims of even taller trees, the tallest being 101 m (331 ft).[4] The natural distribution of the species includes Tasmania and southern Victoria (particularly the Otway Ranges and southern Gippsland). There are also isolated occurrences on King Island and Flinders Island in Bass Strait and on the summit of the You Yangs near Geelong. There are naturalised non-native occurrences in Spain and Portugal, and other parts of southern Europe incl. Cyprus, southern Africa, New Zealand, western United States (California), Hawaii, Macaronesia,[5] and the Caucasus (Western Georgia).[6]

The d'Entrecasteaux expedition made immediate use of the species when they discovered it, the timber being used to improve their oared boats.[7] The Tasmanian blue gum was proclaimed as the floral emblem of Tasmania on 27 November 1962. The species name is from the Latin globulus, a little button, referring to the shape of the operculum.

Description

The bark sheds often, peeling in large strips. The broad juvenile leaves are borne in opposite pairs on square stems. They are about 6 to 15 cm long and covered with a blue-grey, waxy bloom, which is the origin of the common name "blue gum". The mature leaves are narrow, sickle-shaped and dark shining green. They are arranged alternately on rounded stems and range from 15–35 cm (5.9–13.8 in) in length. The buds are top-shaped, ribbed and warty and have a flattened operculum (cap on the flower bud) bearing a central knob. The cream-coloured flowers are borne singly in the leaf axils and produce copious nectar that yields a strongly flavoured honey. The fruits are woody and range from 1.5–2.5 cm (0.59–0.98 in) in diameter. Numerous small seeds are shed through valves (numbering between 3 and 6 per fruit) which open on the top of the fruit. It produces roots throughout the soil profile, rooting several feet deep in some soils.

The plant was first described by the French botanist Jacques Labillardière in his publications Relation du Voyage à la Recherche de la Pérouse (1800) and Novae Hollandiae Plantarum Specimen (1804).[8][9] The author collected specimens at Recherche Bay during the d'Entrecasteaux expedition in 1792.[7]

Plantations

Large blue gum eucalyptus in Pleasanton, California, 46.5 m (153 ft) in height and 10.5 m (34 ft) in circumference.

Blue gum is one of the most extensively planted eucalypts. Its rapid growth and adaptability to a range of conditions is responsible for its popularity. It is especially well-suited to countries with a Mediterranean-type climate, but also grows well in high altitudes in the tropics.[10]

It comprises 65% of all plantation hardwood in Australia with approximately 4,500 km2 (1,100,000 acres) planted.[11] The tree is widely cultivated elsewhere in the world. It is primarily planted as a pulpwood, and also as an important fuelwood in many countries.

Blue gums have historically been used as street trees but are now regarded as unsuitable by many municipalities due to their rapid growth and mature size.

In California, thousands of E. globulus were planted from the late 1800s onward, notably by the ranch owners as windrows to protect citrus groves from the harsh Santa Ana winds, particularly in Orange County. With the decline and eventual disappearance of the citrus business and rapid suburbanisation of the area, the surviving E. globulus became increasingly seen as an important part of the suburban landscape and are currently protected by various city ordinances.

In circa 1860 Francis Cook planted the tree on Monserrate Palace his property at Sintra in Portugal and within twenty years it had attained the height of 100 m and a diameter of 5 m. By 1878 the tree ″... had spread from one end of Portugal to the other″. In 1878 the tree was also planted, partly on Cook's recommendation, in Galway, Ireland to reclaim ″... useless bog land″.[12]

Uses

Timber

Blue gum timber is yellow-brown, fairly heavy, with an interlocked grain, and is difficult to season.[13] It has poor lumber qualities due to growth stress problems, but can be used in construction, fence posts and poles.[14]

Pulpwood

Essential oil

Eucalyptus globulus essential oil in clear glass vial

The leaves are steam distilled to extract eucalyptus oil. E. globulus is the primary source of global eucalyptus oil production, with China being the largest commercial producer.[15][16] The oil has therapeutic, perfumery, flavoring, antimicrobial and biopesticide properties.[17][18][19] Oil yield ranges from 1.0-2.4% (fresh weight), with cineole being the major isolate. E. globulus oil has established itself internationally because it is virtually phellandrene free, a necessary characteristic for internal pharmaceutical use.[20] In 1870, Cloez, identified and ascribed the name "eucalyptol" — now more often called cineole — to the dominant portion of E. globulus oil.[21]

Herb tea

Tasmanian blue gum leaves are used as an herbal tea.[22]

Honey

Blue gum flowers are considered a good source of nectar and pollen for bees.

Phenolics

E. globulus bark contains quinic, dihydroxyphenylacetic and caffeic acids, bis(hexahydroxydiphenoyl (HHDP))-glucose, galloyl-bis(HHDP)-glucose, galloyl-HHDP-glucose, isorhamentin-hexoside, quercetin-hexoside, methylellagic acid (EA)-pentose conjugate, myricetin-rhamnoside, isorhamnetin-rhamnoside, mearnsetin, phloridzin, mearnsetin-hexoside, luteolin and a proanthocyanidin B-type dimer, digalloylglucose and catechin.[23] The hydrolyzable tannins tellimagrandin I, eucalbanin C, 2-O-digalloyl-1,3,4-tri-O-galloyl-β-D-glucose, 6-O-digalloyl-1,2,3-tri-O-galloyl-β-D-glucose, as well as gallic acid and (+)-catechin can also be isolated.[24] Tricetin is a rare flavone aglycone found in the pollen of members of the Myrtaceae, subfamily Leptospermoideae, such as E. globulus.[25]

Environmental weed

It was introduced to California in the mid-19th century, partly in response to the Southern Pacific Railroad's need for timber to make railroad ties, and is prominent in many parks in San Francisco and throughout the state. Naturalists, ecologists, and the United States National Park Service consider it an invasive species due to its ability to quickly spread and displace native plant communities, while local authorities, especially many fire departments across California consider them to be a major fire hazard,[26][27][28] although the United States Department of Agriculture does not list it among its "Invasive and Noxious plants" list in California.[29] Due to such reasons, programs across the state of California have been taken to remove all eucalyptus growth and restore native biomes in some park areas, such as on Angel Island in San Francisco Bay, and in the Hills of Oakland, California.

Related species

Many botanists treat the Tasmanian Blue Gum as a subspecies of a broader species concept. This broader E. globulus includes the following subspecies:

The broader E. globulus concept is supported by Royal Botanic Gardens, Melbourne[30] and the Tasmanian Herbarium,[31] but not by Royal Botanic Gardens, Sydney[32] where the four taxa are considered distinct species.

See also

References

  1. ↑ "Eucalyptus globulus". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 19 January 2016.
  2. ↑ "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-02-25. Retrieved 2014-10-17.
  3. ↑ Giant Trees Consultative Committee
  4. ↑ Lewin, D. W. 1906: The Eucalypti Hardwood Timbers of Tasmania
  5. ↑ "GRIN Taxonomy for Plants - Eucalyptus globulus". United States Department of Agriculture.
  6. ↑ ka:ევკალიპტი ევკალიპტი
  7. 1 2 Mulvaney, John (c. 2006). "4. Botanising". ‘The axe had never sounded’: place, people and heritage of Recherche Bay, Tasmania (Online ed.). Australian National University. ISBN 978-1-921313-21-9. Retrieved 2009-02-16.
  8. ↑ "Eucalyptus globulus Labill.". Australian Plant Name Index (APNI), IBIS database. Centre for Plant Biodiversity Research, Australian Government.
  9. ↑ IPNI citation: Eucalyptus globulus Labill. Voy. i. 153. t. 13; Nov. Holl. Pl. ii. 121.
  10. ↑ Hillis, W.E., Brown, A.G., Eucalypts for Wood Production, Academic Press, 1984, p20, ISBN 0-12-348762-5
  11. ↑ Australia's Plantations 2006 (PDF). Bureau of Rural Sciences. Retrieved 2007-01-24.
  12. ↑ "The Eucalyptus for the West of England". The Cornishman (16). 31 October 1878. p. 5.
  13. ↑ Cribb, A.B. & J.W., Useful Wild Plants in Australia, Collins 1982, p25 ISBN 0-00-636397-0
  14. ↑ Index of Species Information, Eucalyptus globulus
  15. ↑ Edited by Boland,D.J., Brophy, J.J., and A.P.N. House, Eucalyptus Leaf Oils - Use, Chemistry, Distillation and Marketing, Inkata Press, 1991, p4.
  16. ↑ Eucalyptus Oil, FAO Corporate Document Repository
  17. ↑ Eucalyptus globulus Monograph, Australian Naturopathic Network
  18. ↑ Eucalyptus globulus, Association of Societies for Growing Australian Plants (ASGAP)
  19. ↑ Young-Cheol Yang, Han-Young Choi, Won-Sil Choi, J. M. Clark, and Young-Joon Ahn, Ovicidal and Adulticidal Activity of Eucalyptus globulus Leaf Oil Terpenoids against Pediculus humanus capitis (Anoplura: Pediculidae), J. Agric. Food Chem., 52 (9), 2507 -2511, 2004.
  20. ↑ Edited by Boland,D.J., Brophy, J.J., and A.P.N. House, Eucalyptus Leaf Oils - Use, Chemistry, Distillation and Marketing, Inkata Press, 1991, p3., & pp78-82.
  21. ↑ Boland, D.J., Brophy, J.J., and A.P.N. House, Eucalyptus Leaf Oils, 1991, p6 ISBN 0-909605-69-6
  22. ↑ Eucalyptus Globulus Labill Leaf Pieces Tea
  23. ↑ Santos, SA; Freire, CS; Domingues, MR; Silvestre, AJ; Pascoal Neto, C (2011). "Characterization of phenolic components in polar extracts of Eucalyptus globulus Labill. Bark by high-performance liquid chromatography-mass spectrometry". Journal of Agricultural and Food Chemistry 59 (17): 9386–93. doi:10.1021/jf201801q. PMID 21761864.
  24. ↑ Hou, Ai-Jun; Liu, Yan-Ze; Yang, Hui; Lin, Zhong-Wen; Sun, Han-Dong (2000). "Hydrolyzable Tannins and Related Polyphenols fromEucalyptus globulus". Journal of Asian Natural Products Research 2 (3): 205–12. doi:10.1080/10286020008039912. PMID 11256694.
  25. ↑ The Unique Occurrence of the Flavone Aglycone Tricetin in Myrtaceae Pollen. Maria G. Campos, Rosemary F. Webby and Kenneth R. Markham, Z. Naturforsch, 2002, 57c, pages 944-946 (article)
  26. ↑ "Conflagration Overview". Sfmuseum.org. 1991-10-20. Retrieved 2013-08-18.
  27. ↑ Jim Staats (2008-09-13). "Eucalyptus tree removal riles Tamalpais Valley - Marin Independent Journal". Marinij.com. Retrieved 2013-08-18.
  28. ↑ California Invasive Plant Council (Cal-IPC) Invasive Plant Inventory 2006 http://www.cal-ipc.org/ip/inventory/pdf/Inventory2006.pdf
  29. ↑ "California State Noxious Weeds List | USDA PLANTS". Plants.usda.gov. 2003-10-20. Retrieved 2013-08-18.
  30. ↑ "A Census of the Vascular Plants of Victoria". Royal Botanic Gardens, Melbourne.
  31. ↑ "The Tasmanian Herbarium".
  32. ↑ "Flora of New South Wales". Royal Botanic Gardens, Sydney.

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