If you’ve ever walked through a forest of ancient Southern Beech (Nothofagus spp.) you can be forgiven for believing that you have just stepped into another world. You often find these trees growing as rings of giant trunks, covered in hundreds of epiphytes and mosses, but don’t be fooled.
The rings of trunks are just the one tree! It’s called coppicing; the tree sends out new shoots radially from the base of the original trunk, and these shoot eventually grow into clones of the parent tree forming a ring of tunks, all belonging to the one tree.
These circles of moss laiden, gnarly, 50 metre high trees, coupled with the mists of high altitude forests create an atmosphere of ancient druid forests. Almost mystical. But in reality, these forests are from a world that existed long before Gandalf and the druids.
The southern beech forests evolved some 100 million years ago, when dinosaurs roamed and Australia was still part of the super-continent, Gondwana. Between 160 and 65 million years ago Gondwana split apart, forming today’s southern land masses: Antarctica, South America, Africa, Madagascar, Australia, New Guinea, New Caledonia and New Zealand.
Nothofagus provide a classic example of how continental drift influenced species distribution. As the pieces of Gondwana moved to their present positions, they carried these ancient trees with them. That’s why Nothofagus forests are only found in South America (Chile & Patagonia), New Zealand, Australia (Tasmania and from Victoria to southern Queensland), New Guinea, and New Caledonia.
Fossilised pollen grains of Nothofagus have also been found in Antarctica – showing that Antarctica was once warmer than today, forested and connected to the other southern land masses.
Being on different continents for thousands of years has let these trees evolve independently but they are still classed as the one family (Nothofagaceae).
Conditions in Australia 65 million years ago were temperate and moist with high rainfall. Nothofagus and other rainforest species were widespread across the continent and fossil evidence suggests that these Gondwanan forests hosted a huge diversity of plants and animals. As Australia continued to move northward the climate got warmer and drier. The Nothofagus forests retreated to the moister east coast and the highlands.
Since then, European settlement, land clearing for agriculture and logging of the forests has reduced the Nothofagus to small fragments of forest throughout south eastern Australia, mainly in national parks.
There are three species of Nothofagus in Australia. Stands of Nothofagus cunninghamii (Myrtle beech) exist in the Tarkine Forest of Tasmania, an area well known for its ancient gondwanan forests, but an area yet to receive national park or world heritage status. There are also some small stands of this species in the Great Otway National Park, in Victoria.
The deciduous Antarctic beech (N. gunnii) also occurs in Tasmania and is the only deciduous tree to have evolved in Australia.
The Antarctic beech (N. moorei) is found between Barrington Tops National Park in New South Wales and Lamington National Park in southern Queensland. Almost all of the forest fragments of this species are protected as part of the Gondwana Rainforests of Australia World Heritage Area.
When Australia was covered by Gondwanan forests, Nothofagus supported a great diversity of life. So we ask, do today’s fragmented forests still support a high level of biodiversity?
The patches of Nothofagus forest throughout NSW and Qld still have an extremely high conservation value and provide habitat for more than 200 rare and threatened plant and animal species, including the giant barred frog (Mixophyes iteratus). Nothofagus forests within the Border Ranges National Park in northern NSW support the greatest concentration of frog, snake, bird and marsupial species in Australia .
The forests within the Gondwanan Rainforests of Australia world heritage area support more than 400 species of plants, including 50 species of climbers and 40 species of epiphytes (plants that grow on other plants) . In Tasmania, the Nothofagus forests of the Tarkine also support an enormous array of fish, amphibians, reptiles, birds and mammals.
So yes, despite being fragmented and isolated, Australia’s Nortofagus forests are very biodiverse.
It’s reassuring to know that some protection is now in place for Australia’s remaining Nothofagus forests however, many of these forest fragments are surrounded by fire prone eucalypt forest and agricultural areas.
Nothofagus are slow to recover from fire, unlike Australian eucalypt species, which have adapted to Australia’s hot, dry climate and fire regime . Climate scientists predict the intensity and frequency of bush fires in Australia to increase with slight changes in regional temperature (1 – 2°C). Unfortunately this is bad news for Nothofagus because they are slow to regenerate. Increases in fire frequency may threaten the existence of these ancient forests in Australia.
So next time you’re walking through these Gondwanan forests and see a ring of trees, remember they’re probably just one individual of an ancient species with relatives in other distant southern lands.
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 http://www.publish.csiro.au/paper/SB9930429 (CSIRO 1993)
 (Journal of Ecology) http://www3.interscience.wiley.com/journal/118509737/abstract