Tasmanian Tree Fern (Dicksonia antarctica) is an evergreen tree fern native to parts of Australia, namely New South Wales, Tasmania, and Victoria.

Anatomy and biology

These ferns grow to 15 m in height, 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 up to 6 m in diameter. The shapes of the stems vary as some grow curved and there are multi-headed ones.

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. Plants 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 simply 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 a slow rate of about 3.5 to 5 cm per year and produces spores at the age of about 23 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 habitat of this fern is 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 Tasmania.

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

It is particularly suited to garden planting and landscaping purposes and is one of the most popular tree ferns in the world. A very 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.

Trivia

The Tasmanian Tree Fern can be used as a food source, with the pith of the plant being eaten either cooked or raw. It is a very good source of starch.

This species is also known as the Soft Tree Fern, and in Tasmania they are known as Man Ferns.

References

• Tasmanian Tree Fern

• Australian National Botanic Gardens: Dicksonia antarctica – the soft tree fern