Tasmania possesses a large number of plant species that occur nowhere else in the world. Our
alpine communities are particularly significant habitats for these endemic plants. One group of plants occurring in these habitats, the native conifers, is of particular botanical significance. The conifers evolved and became the dominant land plants during the era of the dinosaurs. Many of Tasmania's conifers are very primitive. In most areas of Australia conifers have been replaced in importance by flowering plants. Tasmania is one of the few places in Australia where these primitive species can be easily seen dominating forest. Conifers have also played an important part in Tasmania's convict and industrial history.
(None of Tasmania's conifers are strictly pines, that is, belonging to the genus
. The common names, whilst resulting from a misappropriation of this word, are too embedded in common use to be changed.)
The Huon pine (Lagarostrobos franklinii)
derives its common name from the stands which once occurred along the Huon River, itself named after Huon de Kermandec, commander of the French ship, L'Esperance. The species is restricted to western and southern Tasmania, where it is largely confined to riverine habitats. The value of Huon pine timber for boat building and furniture making led to the establishment of the pining industry very early in the history of European settlement of Tasmania. Convicts at Macquarie Harbour harvested Huon pines along the Gordon River and built ships at Sarah Island.
The genus Lagarostrobos
evolved 68 million years ago, and was once widely distributed around the southern hemisphere. It is now restricted to Tasmania where it is estimated to occur over an area of 10 500 ha. Since white settlement in Tasmania, the extent of the Huon pine forests has been reduced by inundation, logging and mining. At least 800 ha of huon pine forest has also been killed by fire. Today, the remaining stands are well protected within reserves, the majority being within the
Tasmanian Wilderness World Heritage Area.
Although extremely slow growing, the tree may attain heights of over 40 m. Growth rates average a mere 1mm in diameter per year, but can vary from 0.3 mm to 2 mm, depending on conditions. Huon pine can reproduce both vegetatively (from fallen individuals) and by seed. Seed dispersal is largely limited to the area downstream from riverine stands.
The Huon pine can reach prodigious ages, often in excess of 2000 years, making it among the longest-lived organisms on Earth. Only the bristle-cone pine of North America exceeds it in age. International headlines were made with the discovery of a stand of Huon pines on Mt Read that was widely quoted as being in excess of 10 000 years of age. All the individuals in this population are genetically identical, are all male trees, and so cannot produce seed. The stand arose from one or a small number of individuals, and has maintained itself by vegetative reproduction. It is important to remember that no individual tree in the Mt Read stand is 10 000 years old (in fact, most if not all stems are less than 1000 years old) - rather, the stand itself has been in existence for that long.
The celery-top pine
is so named due to the resemblance of its 'leaves' to those of celery. In fact, these are not true leaves, but rather cladodes (flattened stems); only the seedlings of this plant produce true needle-like leaves but these are replaced by the adult 'cladodes' as it grows. Needle leaves have a small surface area for light reception and the evolution of the flat wide cladodes is thought to be an adaptation to the low light levels in wet forest and rainforest where this species lives. The tree grows to 30 m in height and may attain an age of 800 years. The seeds of this plant are dispersed by birds. Young trees are often found growing in clusters around the base of tall old eucalypts that have survived a fire and are preferentially used for perching by birds. Birds are attracted to the fleshy red 'aril' that is produced below the seed of the celery-top pine, which is also enclosed by in a fleshy white sheath.
This slow-growing tree was once readily available as a bi-product from clear-fell operations in old-growth forest and was typically used for external cladding and poles in the building industry.
King billy pine
The king billy pine (Athrotaxis selaginoides)
is thought to derive its common name from the Tasmanian Aborigine William Lanney, who was referred to as 'King Billy'. It reaches a height of 40 m and may reach ages in excess of 1200 years. The species is largely restricted to regions above 600 m where it grows in highland rainforest. It is one of the most cold tolerant trees in Tasmania able to survive temperatures of -17 degrees Celsius. Athrotaxis
is the most primitive palaeoendemic in Tasmania, with an estimated age of 150 million years. Fossils of the genus have been found in South America but the genus is now restricted to Tasmania.
A close relative of the king billy pine, the pencil pine (Athrotaxis cupressoides), is generally restricted to sub-alpine areas above 800 m. Like its relative, it can reach ages greater than 1200 years and is the most frost hardy tree known in Tasmania, surviving temperatures of -20 degrees Celsius. The seeds of this tree and king billy have a dispersal distance of less than the height of the parent tree. These species do not produce seed every year but, instead, certain climatic triggers produce a synchronous seeding event when most trees produce large quantities of seed. These 'mast years' occur once every 5 years on average.
However, while seeds are produced in large numbers seedlings rarely survive the pressure of browsing, competition and most regeneration appears to be vegetative.
Pencil pines are often seen around the shores of highland lakes and tarns, creating a fairyland mien of unparalleled beauty.
Coniferous heathland species
In addition to the better known coniferous trees in Tasmania, there are also several coniferous shrubs that occur in the alpine and subalpine heathlands. The most ancient of these plants is the creeping pine (Microcachrys tetragona). Only one species remains for the genus which is now restricted to western Tasmania. Fossils plants in this genus have been found widely distributed around the southern hemisphere. The genus is estimated to have evolved about 130 million years ago. Another ancient genus is Pherosphaera, dates back 115 million years. One of the species still extant in this genus, is the Mount Mawson pine (Pherosphaera hookeriana), which is restricted to Western Tasmania where it is most common within the Mount Field National Park. Microcachrys and Pherosphaera are both genera within the family Podocarpaceae. Another common species in Tasmania's coniferous heathlands is the dwarf pine (Diselma archeri), a member of the family Cupressaceae, which dates back 37 million years.
At the mercy of fire
The native conifers described on this page, which all occur in high rainfall regions of the state, are highly susceptible to fire. Extensive stands of dead 'stags' give testimony to the ravages of previous fires. Some of the largest pure stands of pencil pine have been lost due to campfires which have escaped. Their very slow growth and poor seed dispersal abilities, reduces the chances of these species re-establishing after fire. Indeed, one-third of the State's King Billy pines have been eliminated by fire since European settlement.
The Tasmanian Wilderness World Heritage Area has been declared a "fuel stove only area" in an attempt to prevent the loss of further conifer stands, as well as rainforest and alpine communities, which are also highly susceptible to fire.