Fieldnotes: Tasmania: Dicksonia antarctica

Facing south from Tasmania, say at the mouth of the River Derwent, or from the outlook at The Neck on Bruny Island, I’m looking towards Antarctica, a place that hardly seemed real to me before coming here. This year the hundredth anniversary of Douglas Mawson’s Australasian Antarctic Expedition of 1911-1914 was widely celebrated in Hobart. Mawson and his party spent two years on the icy continent, initiating Australian involvement with the place.

Both Australian and French Antarctic research stations are supplied from Hobart, and tours to Antarctica often dock here. At the moment the Australian research icebreaker and supply ship, Aurora Australis is sailing to the rescue of a Russian research and tour boat that became locked in ice on its way there. Yesterday a Chinese ice-breaker itself became stuck in an attempt to break through to the Russian ship.

But the Antarctic is present here in other ways too. Dicksonia antarctica is the largest of three species of tree ferns found in Australia. Antarctica here refers to the southern polar region where the fern grows. Dicksonia honours James Dickson (1738-1822), a Scottish nurseryman who ran a business in Covent Gardens. He was one of the original members of the British Linnean Society, and a frequenter of Joseph Banks’s library and collections.

Tree ferns are one of the most spectacular plants I’ve encountered in Tasmania. D. Antarctica, the only one I know for sure I’ve seen, grows up to 15 metres in height, spreads a canopy up to 6 metres wide, and looks to have a trunk. The trunk is really the stem, where older fronds have dried and fallen away. These ferns grow 3.5 to 5 cm per year and take about 20 years before they produce spores.

I first encountered tree ferns when I was here in 2009, and heard them called man ferns because of their size. They have a remarkable presence. Other common names are Australian tree fern, Tasmanian tree fern, hardy tree fern, soft tree fern, woolly tree fern. I encountered them again on Christmas Eve, when we stopped for a short walk to Nelson Falls on our drive to Corinna. (For more about Nelson Falls see http://www.parks.tas.gov.au/?base=1568)

Tree fern on the walk to Nelson Falls

In poet Gwen Harwood’s letters she describes man ferns lining the streets of Hobart when the king and queen came to visit. In later letters she notes their decline in the forest on Mount Wellington. These spectacular giant ferns have long been in demand for landscape gardens in Europe and North America. They are keystone species in wet forests, and have been sold by lumber companies clear-cutting in rainforest and old growth tracts.