Araucaria bidwillii

Araucaria bidwillii
Conservation status
Least Concern
Scientific classification
Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Araucariaceae
Genus:	Araucaria
Species:	A. bidwillii
Binomial name
Araucaria bidwillii (Molina) K. Koch

Araucaria bidwillii is a large evergreen coniferous tree in the genus Araucaria, family Araucariaceae. It is native to south-east Queensland with two small disjunct populations in northern Queensland's World Heritage listed Wet Tropics, and many fine old specimens planted in New South Wales. It can grow up to 50 m.

The bunya pine (A. bidwillii) is the last surviving species of the Section Bunya of the genus Araucaria. This section was diverse and widespread during the Mesozoic with some species having cone morphology similar to A. bidwillii, which appeared during the Jurassic. Fossils of Section Bunya are found in South America and Europe.

Distribution

A. bidwillii has a limited distribution within Australia and, part of the reason for the remnant sites, was the drying out of Australia with loss of rainforest and poor seed dispersal. The remnant sites at the Bunya Mountains, Jimna area and at Mt Lewis in Queensland have genetic diversity at these scattered sites. The cones are large, soft-shelled and nutritious and fall intact to the ground beneath the tree before dehiscing. The possibility of past larger animal as vectors since the Jurassic, such as dinosaurs and large mammals should be considered, but is obviously unprovable for the bunya.

Ecology

Although there are no reported dispersal agents for the seeds of A. bidwillii, macropods and various species of rats are know as predators of the seeds and tubers. It was observed the bush rat (Rattus fuscipes) was caching bunya seeds a limited distances uphill from parent trees, possibly allowing ridge-top germination. Brushtail possums (Trichosurus spp.) were mentioned as carrying the seeds up trees. From a study in 2006, the short-eared possum (Trichosurus caninus) was shown to disperse the seed of A. bidwillii.

A. bidwillii has unusual cryptogeal seed germination in which the seeds develop to form an underground tuber from which the aerial shoot later emerges. The actual emergence of the seed is then known to occur over several years presumably as a strategy to allow the seedlings to emerge under optimum climatic conditions or, it has been suggested, to avoid fire. This erratic germination has been one of the main problems in silviculture of the species.

Natural populations of this species have been reduced in extent and abundance through exploitation for its timber, the construction of a dam and historical clearing. Most populations are now protected in formal reserves and national parks.

The fruit of Bunya, commonly known as the Bunya nut.

The cones are 20-35 cm in diameter, and disintegrate when mature to release the large (3-4 cm) seeds.

Cultural significance

A. bidwillii was a sacred tree for the Aboriginal people. The vernacular name is Bunya, Bonye, Bunyi or Bunya-bunya, from various tribes or European variations of the Australian Aboriginal name for the tree; it is also often called Bunya Pine (though this is inaccurate as it is not a pine). It is also commonly referred to as the False Monkey Puzzle, despite its obvious physical differences from the Monkey Puzzle tree (Araucaria araucana). The seeds are edible, and are similar to pine nuts, and have been an important food resource for Australian Aboriginal people; groves of the trees were often under particular tribal ownership. They are eaten both raw and cooked. Traditionally they were also ground and made into a paste, which was eaten directly or cooked in hot coals to make bread.

Cultivation

A pair of Bunya seedlings showing the change in leaf colour. The cotyledons are hypogeal, remaining below the ground.

Bunya nuts are slow to germinate. A set of 12 seeds sown in Melbourne took on average about six months to germinate (with the first germinating in 3 months) and only developed roots after 1 year. The first leaves form a rosette and are dark brown. The leaves only turn green once the first stem branch occurs. Unlike the mature leaves, the young leaves are relatively soft. As the leaves age they become very hard and sharp.

They can be found in southern Texas and Florida.

Once established Bunyas are quite hardy and can be grown as far south as Hobart in Australia (42° S) and Christchurch in New Zealand (43° S) and as north as Sacramento in California (38° N).

References

• Template:IUCN2006
• Haines R. J. (1983) Embryo development and anatomy in Araucaria Juss. Australian Journal of Botany. 31, 125-140.
• Haines R. J. (1983) Seed development in Araucaria Juss. Australian Journal of Botany. 31, 255-267.
• Hernandez-Castillo, G. R., Stockey R. A.(2002) Palaeobotany of the Bunya Pine In (Ed. Anna Haebich) ppl 31-38. ‘On the Bunya Trail’ Queensland Review – Special Edition, Volume 9, No. 2, November 2002 (University of Queensland Press: St Lucia).
• Pye M.G., Gadek P. A. (2004) Genetic diversity, differentiation and conservation in Araucaria bidwillii (Araucariaceae), Australia's Bunya pine. Conservation Genetics .5, 619-629.
• Smith I. R., Withers K., Billingsley J. (2007) Maintaining the Ancient Bunya Tree (Araucaria bidwillii Hook.) - Dispersal and Mast Years. 5th Souther Connection Conference, Adelaide, South Australia 21-25th January 2007.
• Smith I. R. (2004) Regional Forest Types-Southern Coniferous Forests In ‘Encyclopedia of Forest Sciences’ (eds. Burley J., Evans J., Youngquist J.) Elsevier: Oxford. pp 1383-1391.
• Smith I. R., Butler D (2002) The Bunya in Queensland’s Forests, In (Ed. Anna Haebich) ppl 31-38. ‘On the Bunya Trail’ Queensland Review – Special Edition, Volume 9, No. 2, November 2002 (University of Queensland Press: St Lucia).

External links

• Gymnosperm Database: Araucaria bidwillii
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