The Wollemi Pine is perhaps the rarest plant on the planet, and is certainly one of the oddest. Prior to its discovery in 1994 in a canyon less than 100 miles from Sydney, a bustling metropolis of 4.3 million people, Wollemia Nobilis
was known only from fossil records in Australia, New Zealand and the Antarctic that date back 90 million years. It is thought that the pines may have existed since the Jurassic period 200 million years ago, back from when these places were all a part of the Gondwana super-continent, before plate tectonics broke it up and Australia drifted north.
This tree, now growing in the protection of the Australian National Botanic Gardens, is in a locked, protective cage that was opened up specially for this photo shoot (see the accompanying page “Behind the scenes – how this panorama was made”) is not only rare, it is fragile because of its genetic structure – all of the 100 or so trees now known to exist in nature share the same DNA, as if they were cloned. It is believed by the scientific community that it is the only plant known in the world that has absolutely no genetic diversity. Research has revealed that the pines are all genetically identical, a condition previously unknown among sexually reproducing organisms. Scientists are being forced to rethink genetic theory as a consequence. Millions of years of inbreeding seems to have removed differences in the existing population’s DNA, and when combined with their radically different method of growing, it has made the remaining trees liable to genetic pathogens that could destroy the entire remaining natural population.
Although the Wollemi Pine is able to produce viable seeds – you can see some small cones on the tree - it appears to be clonal. It is capable of reproduction through buds that are carried in the axils of leading vertical shoots. Some dormant buds may sprout along the trunk or from the base of the trunk. This is known as “coppicing” and results in large, old, plants with multiple trunks of different ages. Most trunks arise from a common base, but some may arise from the suckering of larger roots, just like immense Jurassic strawberries. Trunks have also developed from the sprouts that emerge from dormant buds of fallen branches. Field observations indicate that only the largest and hence oldest trunks reproduce sexually, and all but one of the wild adult trees appears to have many trunks.
The biggest wild Wollemi Pine is known as “King Billy”, and that tree probably produced the beautiful specimen that lives in the Australian National Botanic Gardens. King Billy is 38 metres high, but has several trunks, making the true growth of this tree over its life some 150 metres or more. The Wollemi Pine is slow growing when mature at less than one centimetre per year, and it is thought that while the main trunk of King Billy may “only” be up to 400 years old, the tree's roots could have been around since the time of the Roman Empire. King Billy and his clones’ location has been kept a dark secret to protect their continued existence, and several trees have been grown and are now in gardens in London, Edinburgh, Dublin, Brussels, Amsterdam, Vienna, Frankfurt, Tokyo and Taipei, so the long-term survival now seems likely. Commercial propagation is also underway.
Records show that the Wollemi Pine in its remaining natural environment grows at an altitude between 670 and 780 metres above sea level, in shady canyons, and can survive in temperature extremes of at least between –5 and 45 degrees Celsius. The National Botanic Garden in Canberra provides a home for this special plant at about 700 metres, and Canberra’s recorded temperature range is –10 to 42 degrees, so this may make these beautiful gardens a nice home for this youthful specimen for the next thousand or so years.
Thanks to Jo Sedman at the Gardens for arranging such special access – visit the gardens at http://www.anbg.gov.au/anbg/index.html
Facts for this essay were derived from information sourced from the Australian National Botanic Gardens, and the NSW Botanic Gardens.