|Tasmania’s endemic Huon Pine
(Lagarostrobos franklinii, Family Podocarpaceae) is
famous around the world as an extremely durable boat-building timber
and as a beautiful, golden-coloured, easily workable furniture timber.
Its durability is due to the presence of a unique oil, methyl euganol,
which permeates the wood, making it virtually impervious to rot and
giving the timber a distinctive sweet smell. The trees grow within
forests along the rivers and streams of Western Tasmania and along the
Huon River in the south, where it was first discovered and named.
It was discovered soon after the settlement of Hobart in 1803, in the form of logs which had been washed up along the shores of the Huon River and D’Entrecastreaux Channel. These were free from rot, despite having lain there for decades or hundreds of years. Extensive logging of Huon Pine from the western rivers took place throughout the 1800’s and into the mid-1900’s, with Strahan on the West Coast being the main milling centre.
Stockpile of Huon Pine logs held in a quarry in Queenstown. The rich golden colour is evident on the sawn ends. Photo: K. Corbett
|Assessment of the extent and
status of the pine stands through the 1980’s and 1990’s followed concerns
about its possible decline, and today some 85% of the trees are in reserves,
and logging is restricted to salvage from flooded areas of hydro-electric
impoundments, and of dead timber from the previously- logged Teepookana
Plateau near Strahan.
Huon Pine is very slow growing, with a dense grain and close-spaced growth rings. The oldest living trees are of the order of 3000 years old (only the bristle cone pine of California, Pinus longaeva, achieves greater age). Huon Pine pollen occurs in Victorian lake sediments 150,000 years old, and similar pollen is found in 100 million year old sediments, indicating that the pines have been around since Australia was part of Gondwana.
Could a tree be 10,000 years old? - read on...
One particular Huon Pine occurrence which recently received international attention is the small (1ha) forest patch high on the slopes of Mt Read, near Rosebery. Here, in the wettest part of Tasmania, at an altitude of 1000m (the highest known for Huon Pine), beside the small glacial Lake Johnston, are several hundred trees which share an extraordinary legacy. All are male and all are genetically identical, forming a clone. No variation in DNA could be found between the trees. Even more astounding was the discovery that Huon Pine pollen was present in the bottom sediments of Lake Johnston, carbon-dated at 10,500 years. There are no other Huon Pines within 20 km of Mt Read, and no female trees anywhere in the area.
Frond of Mt Read Huon Pine from potted specimen grown from
a cutting Photo: J & R Coghlan
|It is concluded that a male tree
became established at Lake Johnston at least 10,500 years ago, and has been
propagating itself vegetatively ever since, so that the identical genes
survive to this day. How it got there originally is an open question, but
as carriage by birds or by wind-blow are unlikely, it most probably arrived
during the last Interglacial (about 30,000 years ago) and somehow survived
through the Last Glacial period. The main method of growth has probably
been by layering – a branch or trunk is weighed down by snow, or partly
broken by wind, and roots develop where it is in contact with soil. A new
stem grows above the new roots, and so the forest slowly expands. A similar
method is commonly seen with the endemic pencil pines, where a copse of multiple
trunks is often seen to be interconnected via fallen trunks or branches.
Thus, while the oldest individual tree or stem on the site now may be one to two thousand years old, the organism itself has been living there continuously for at least 10,000 years – a ‘Methuselah tree’ indeed.
|Another special aspect of the
Mt Read Huon Pine forest is the extraordinary array of other rare and
ancient plants in the area. Most of Tasmania’s other endemic conifers
are also present, including king billy pine (Athrotaxis selaginoides)
and pencil pine (A. cupressoides), and their hybrid A.
laxifolia, the cheshunt pine (Diselma archeri),
creeping pine (Microcachrys tetragona), and celery-top
pine (Phyllocladus asplenifolius). Individuals of four
of these species have been found which are over a thousand years old
– truly an ancient forest. Of particular interest is the presence of numerous
trees of Diselma archeri, a species normally
found only as shrubs. One of these trees, looking very ancient and gnarled,
is over 10 m high, with a trunk about 60 cm diameter (pictured). Also
present is the rare endemic Orites milliganii (Proteaceae),
and an abundance of the endemic deciduous beech (Nothofagus gunnii),
Tasmania’s only native deciduous tree.
Orites milliganii and Nothofagus gunnii at Mt Read
(Left.) Ancient Diselma archeri tree at Lake Johnston. King billy pine and deciduous beech also present.
|International experts have made
detailed studies of the growth rings of the Mt Read Huon Pines, both
living and dead, and have pieced together a tree ring chronology of over
4000 years. Because the rings vary with the climate at the time, and
particularly with temperature, they give a good indication of how the
climate has varied over that time. Of interest in this record is the clear
indication of climate warming since the 1960’s.
So an ancient remnant of the Gondwanan forests has survived as a lonely but determined male at Mt Read, and is able to bring us vital information on the changes it has weathered over thousands of years, and a sense of wonder at the strength and durability of this remarkable species.
Further reading: ‘The Huon Pine Story’ by Garry Kerr and Harry McDermott, 2000, published by Mainsail Books, PO Box 316, Portland, Victoria 3305. ISBN 0 95779170 4
"NORMAL" HUON PINE