Eucalyptus camaldulensis

taxobox
name = River Red Gum

---

image_caption = Main trunk of a 700 yr old Red River Gum in the Wonga Wetlands, NSW
regnum = Plantae
unranked_divisio = Angiosperms
unranked_classis = Eudicots
unranked_ordo = Rosids
ordo = Myrtales
familia = Myrtaceae
genus = "Eucalyptus"
species = "E. camaldulensis"
binomial = "Eucalyptus camaldulensis"
binomial_authority = Dehnh.|

The River Red Gum ("Eucalyptus camaldulensis") is a tree of the genus "Eucalyptus". It is a plantation species in many parts of the world but is native to Australia where it is widespread especially beside inland water courses. Oddly, it is named for a garden near the Camaldoli monastery near Naples (L'Hortus Camaldulensis di Napoli), from where the first specimen came to be described.

It is a familiar and iconic tree seen along many watercourses right across inland Australia. The tree produces welcome shade in the extreme temperatures of central Australia, and plays an important role in stabilising river banks, holding the soil and reducing flooding.

Description

The tree can grow to 45 metres tall; its thick (30mm) spongy, bark is dappled with red, grey, green and white.

River Reds have an ominous name, "Widow Maker", as they have a habit of dropping large (often half the diameter of the trunk) boughs without warningFact|date=September 2008. This may be a means of saving water or simply a result of their brittle wood. This is also an efficient way of attracting wildlife that live in the holes formed which gives the red gum a source of natural fertiliserFact|date=September 2008.

Ecology

The "snags" formed when River Red Gums fall into rivers such as the Glenelg, are an important part of river ecosystems, and vital habitat and breeding sites for native fish like River Blackfish. Unfortunately most snags have been removed from these rivers due to short-sighted water management.

Hollows start to form at around 120 – 180 years of age, creating habitat for many wildlife species.

The Superb Parrot, a threatened species, is amongst the bird species which nest in the River Red Gum [IUCN2006|assessors=BirdLife International|year=2004|id=17962|title=Polytelis swainsonii|downloaded=31 October 2006] .

Formation of the Barmah Red Gum Forests

The formation of the famous Barmah Red Gum Forests is due to a relatively recent geological event in the Murray-Darling Basin involving the Cadell fault.

River Red Gum seeds germinate readily after floods and require regular spring floods throughout their life to survive. In the Murray-Darling Basin, such floods are now rare due to river regulation for irrigation, and as a result, 75% of River Red Gums in the lower Murray are stressed, dead or dying.

The largest remaining stand of River Red Gum is the 65,000ha Barmah-Millewa forest straddling the border of Victoria and New South Wales, due north of Melbourne. It retains enormous cultural significance to the Indigenous traditional owners, the Yorta Yorta Nation. Like many stands of River Red Gum, the Barmah-Millewa has been drastically altered by over 100 years of timber harvesting. There is a paucity of old hollow-bearing trees which provide habitat for rare and threatened fauna such as the Superb Parrot, Brush-tailed Phascogale and Inland Carpet Python. The increasing scale of logging machinery is creating large areas of intensive soil disturbance and bare earth, which is likely to increase weed invasion and increase the likelihood of the extinction of rare understorey plants.

About 25,000 years ago, displacement occurred along the Cadell fault, raising the eastern edge of the fault (which runs north-south) 8-12 metres above the floodplain. This created a complex series of events. A section of the original Murray River channel immediately behind the fault was abandoned, and exists today as an empty channel known as Green Gully. The Goulburn River was dammed by the southern end of the fault to create a natural lake. The Murray River flowed to the north around the Cadell Fault, creating the channel of the Edward River which exists today and through which much of the Murray River's waters still flow. Then the natural dam on the Goulburn River failed, the lake drained, and the Murray River avulsed to the south and started to flow through the smaller Goulburn River channel, creating "The Barmah Choke" and "The Narrows" (where the river channel is unusually narrow), before entering into the proper Murray River channel again.

The primary result of the Cadell Fault however is that the west-flowing water of the Murray River strikes the north-south running fault and diverts both north and south around the fault in the two main channels (Edwards and ancestral Goulburn) as well as a fan of small streams, and regularly floods a large amount of low-lying country in the area. These conditions are perfect for River Red Gums, which rapidly formed forests in the area. Thus the displacement of the Cadell Fault 25,000 BP lead directly to the formation of the famous Barmah River Red Gum Forests.

Cultivation

"E. camaldulensis" readily germinates from both fresh seed and seed stored in cool dry conditions. It quickly toughens up and can withstand drought even whilst in forestry tubes. It makes an excellent bonsai and will readily regrow both from the base and from epicormic buds.

Uses

Red gum is so named for its brilliant red wood, which can range from a light pink through to almost black, depending on the age and weathering. It is somewhat brittle and is often cross-grained, making hand working difficult. Traditionly used in rot resistant applications like stumps, fence posts and sleepers, more recently it has been recognised in craft furniture for its spectacular deep red colour and typical fiddleback figure. It needs careful selection as it tends to be quite reactive to changes in humidity (moves about a lot in service). It is quite hard, dense (about 900 kg/m³), can take a fine polish and carves well. It is a popular timber for wood turners, particularly if old and well-seasoned.

It is also popular for use as firewood. Significant amounts of Victoria and NSW's firewood comes from Red Gums in the Barmah forest.

The wood makes fine charcoal, and is successfully used in Brazil for iron and steel production. In addition, this plant is used for beekeeping in Brazil and Australia.

It is one of the most widely planted eucalypts in the world (ca 5,000 km² planted) (NAS, 1980a). Plantations occur in Argentina, Arizona, Brazil, California, Egypt, Kenya, Morocco, Nigeria, Pakistan, Senegal, Sierra Leone, Spain, Sri Lanka, Sudan, Tanzania, Upper Volta, Uruguay, and Zimbabwe.

References

*CSIRO, 2004. "Eucalyptus camaldulensis" Dehnh. River Red Gum. [http://www.cmis.csiro.au/healthycountry/CCScience/TB/Eucalyptus-camaldulensis/index.html]
*Mackay, Norman and David Eastburn (eds) 1990. "The Murray". Murray-Darling Basin Commission, Canberra. ISBN 1-875209-05-0.

See also

* Mountain ash
* Alpine Ash
* Snow Gum

External links

* [http://www.hort.purdue.edu/newcrop/duke_energy/Eucalyptus_camaldulensis.html Center for New Crops & Plant Products, Purdue University]