Eucalyptus marginata

taxobox
name = Jarrah


regnum = Plantae
unranked_divisio = Angiosperms
unranked_classis = Eudicots
unranked_ordo = Rosids
ordo = Myrtales
familia = Myrtaceae
genus = "Eucalyptus"
species = "E. marginata"
binomial = "Eucalyptus marginata"
binomial_authority = Donn ex Sm.
subdivision_ranks = Subspecies
subdivision = "E. marginata" subsp. "marginata" "E. marginata" subsp. "thalassica"|

"Eucalyptus marginata" is one of the most common species of "Eucalyptus" tree in southwest of Western Australia. The tree and the wood are usually referred to by the Aboriginal name Jarrah. Because of the similar appearance of worked jarrah timber to the Honduras mahogany tree, jarrah was once called Swan River mahogany after the river system that runs through Perth.

Description

The tree grows up to 40 m high with a trunk up to 3 m in diameter, and has rough, greyish-brown, vertically grooved, fibrous bark which sheds in long flat strips. The leaves are often curved, 8-13 cm long and 1.5-3 cm broad, shiny dark green above and paler below. The species' scientific name "marginata" refers to the light-coloured vein on the border around its leaves. The stalked flower buds appear in clusters of 7-11; each bud has a narrow, conical bud cap 5-9 mm long. The flowers are white, 1-2 cm diameter, and bloom in spring and early summer. The fruits are spherical to barrel-shaped, and 9-16 mm long and broad.

The bark of this "Eucalyptus" is not shed in patches as it is with many others, but splits into fibrous strips. Jarrah trees are also unusual in that they have a lignotuber, a large underground swelling which stores carbohydrates and allows young trees to regenerate after a fire. Because they are deep-rooted, as much as 40 m, jarrah are drought resistant and able to draw water from great depths during dry periods.

Ecology

Jarrah is an important element in its ecology, providing numerous habitats for animal life - especially birds and bees - while it is alive, and in the hollows that form as the heartwood decays. When it falls, it provides shelter to ground-dwellers such as the chuditch ("Dasyurus geoffroii"), a marsupial cat.

Jarrah has shown considerable adaptation to different ecologic zones - as in the Swan Coastal Plain and further north, and also to a different habitat of the lateritic Darling Scarp. [Powell, Robert James and Emberson, Jane (1978)."An old look at trees : vegetation of south-western Australia in old photographs" Perth : Campaign to Save Native Forests (W.A.). ISBN 0959744932 - has photographs of significant large old Jarrah trees from the Swan Coastal Plain in the late 1800s and early 1900s]

Jarrah is very vulnerable to "dieback", the alga "Phytophthora cinnamomi", which causes root-rot. In large sections of the Darling Scarp there have been various measures to reduce the spread of dieback by washing down vehicles, and restricting access to areas of forest not yet infected.

Uses

Jarrah flowers are used to make honey, but its wood is its main use. It is a heavy timber, with a specific gravity of 1.1 when green. Its long, straight trunks of richly coloured and beautifully grained termite-resistant timber make it valuable for cabinet making, flooring, panelling and outdoor furniture. The finished timber has a deep rich reddish-brown colour and an attractive grain. When fresh, jarrah is quite workable but when seasoned it becomes so hard that conventional wood-working tools are useless. It is very durable, even in wet and weathered situations, making it a choice structural material for bridges, wharves, railway sleepers, ship building and telegraph poles.

Jarrah wood is very similar to that of Karri, "Eucalyptus diversicolor". Both trees are found in the south west of Australia, the two timbers are frequently confused. They can be distinguished by cutting an unweathered splinter and burning it: karri burns completely to a white ash, whereas jarrah forms charcoal. Most of the best jarrah has been cut out of south Western Australia.

A large amount was exported to the United Kingdom, where it was cut into blocks and covered with asphalt for roads. One of the large exporters in the late nineteenth century was M. C. Davies who had mills in the Margaret River to Augusta region of the south west, and ports at Hamelin Bay and Flinders Bay.

The local poet 'Dryblower Murphy' wrote a poem in the early twentieth century about the potential to extract alcohol from jarrah timber "Comeanavajarrah" [ found in "Jarrahland Jingles"] , suggesting that the resource was an endless one for exploitation. Significantly most of the companies that exploited jarrah in the early twentieth century no longer exist.

Jarrah has become more highly prized, and supports an industry that recycles it from demolished houses. Even so, in 2004, old 4 inch by 2 inch (10 cm by 5 cm) recycled jarrah is routinely advertised in Perth papers for under AUD $1.50 per metre. Larger pieces of the timber were produced in the early history of the industry, from trees of great age, and these are also recovered from the demolition of older buildings.

Offcuts and millends, dead and fire affected jarrah also sell as firewood for those using wood for heating in Perth, and 1 tonne loads can now [Winter 2005] exceed AUD $160 per load. Jarrah tends to work well in slow combustion stoves and closed fires and generates a greater heat than most other available woods.

Jarrah is used in musical instrument making, for percussion instruments and guitar inlays.

Because of it's remarkable resistance to rot, jarrah is used to make hot tubs.

ee also

* "Eucalyptus patens"
* "Jarrah forest"
* "Jarrah-Karri forest and shrublands

References

Further reading

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External links

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