Dicksonia antarctica

Dicksonia antarctica
Dicksonia antarctica in natural habitat in Gippsland, Australia.
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Pteridopsida
Order:	Cyatheales
Family:	Dicksoniaceae
Genus:	Dicksonia
Species:	D. antarctica
Binomial name
Dicksonia antarctica Labill. 1807

Shoot

Dicksonia antarctica, known as the Soft Tree Fern, Man Fern or Tasmanian Tree Fern, is an evergreen tree fern native to parts of Australia, namely south-east Queensland, coastal New South Wales and Victoria and Tasmania.

Anatomy and biology

These ferns can grow to 15 m in height, but more typically grow to about 4.5-5 m, and consist of an erect rhizome forming a trunk. They are very hairy at the base of the stipe (trunk). The large, dark green, roughly-textured fronds spread in a canopy of 2-6 m in diameter. The shapes of the stems vary as some grow curved and there are multi-headed ones. The fronds are borne in flushes, with fertile and sterile fronds often in alternating layers.

The "trunk" of this fern is merely the decaying remains of earlier growth of the plant and forms a medium through which the roots grow. The trunk is usually solitary, without runners, but may produce offsets. They can be cut down and, if they are kept moist, the top portions can be replanted and will form new roots. The stump, however, will not regenerate since it is dead organic matter. In nature, the fibrous trunks are hosts for a range of epiphytic plants including other ferns and mosses.

The fern grows at 3.5 to 5 cm per year and produces spores at the age of about 20 years.

Reproduction

Reproduction by this species is primarily from spores, but it can also be grown from plantlets occurring around the base of the rhizome.

In cultivation, it can also be grown as a "cutting", a method not to be encouraged unless the tree-fern is doomed to die in its present position. This involves sawing the trunk through, usually at ground level, and removing the fronds; the top part will form roots and regrow, but the base will die.

Habitat

The fern grows on damp, sheltered woodland slopes and moist gullies, and they occasionally occur at high altitudes in cloud forests. Dicksonia antarctica is the most abundant tree fern in South Eastern Australia.

The plant can grow in acid, neutral and alkaline soils. It can grow in semi-shade. It strongly resents drought or dryness at the roots, but does best in moist soil.

Cultivation

Dicksonia antarctica in an English garden. The trunk is 60 cm high.

It is particularly suited to garden planting and landscaping purposes. As an ornamental plant, it is hardy to about –5 C, succeeding outdoors in the milder areas of Britain where it thrives and often self-sows in Cornish gardens.

It is best to leave old fronds on the plant in order to protect the trunk from cold and desiccation. Winter protection of the trunk is recommended during prolonged or severe cold weather.

They grow best in areas of rainfall of over 1,000 mm per year but in lower rainfall areas do well in moist gullies. They are tolerant of fire and re-shoot readily after re-location. This plant can provide habitat for epiphytes and also provides shelter for more delicate fern species to flourish underneath.

Plant in organic soils and heavily and regularly mulched and water. Dicksonia antarctica generally requires a minimum rainfall of 500 mm (20 inches) per year. In dry climates, a drip irrigation or spray system applied overhead is the most effective method of watering.

Harvesting

Large Dicksonia antarctica available for sale come from old growth Tasmanian forests, and may be hundreds of years old. The logging practices by the company Gunns, who effectively have a state-monopoly on logging and make these plants available, have been criticized by green groups for several decades. ^[1] The trunks are also available legally from local suppliers who licence collection of minor species from Forestry Tasmania, the State Government GBE who manage forestry.

Edibility

Dicksonia antarctica

The Soft Tree Fern can be used as a food source, with the pith of the plant being eaten either cooked or raw. It is a good source of starch^[2].

References

• Plants For a Future: Dicksonia antarctica
• Australian National Botanic Gardens: Dicksonia antarctica – the soft tree fern
• Large, M.F. and J.E. Braggins 2004. Tree Ferns. Timber Press, Inc. ISBN 0-88192-630-2

1. ^ Flanagan, Richard (May 2007). "Out of control: the tragedy of Tasmania's forests". The Monthly 23: 20–31. 
2. ^ http://www.kew.org/plants-fungi/Dicksonia-antarctica.htm

External links

• Fern Files: Dicksonia antarctica