Wollemia is a genus of coniferous tree in the family Araucariaceae. Wollemia was only known through fossil records until the Australian species Wollemia nobilis was discovered in 1994 in a temperate rainforest wilderness area of the Wollemi National Park in New South Wales, in a remote series of narrow, steep-sided sandstone gorges near Lithgow, 150 kilometres north-west of Sydney.
In both botanical and popular literature the tree has been almost universally dubbed the Wollemi Pine, although it is not a true pine (genus Pinus) nor a member of the pine family (Pinaceae), but rather is related to Agathis and Araucaria in the family Araucariaceae. The oldest fossil of the Wollemi tree has been dated to 200 million years ago.
The Wollemi pine is classified as Critically Endangered (CR - D) on the International Union for Conservation of Nature's Red List 2002,[2] and is legally protected in Australia.
Wollemia nobilis is an evergreen tree reaching 25-40 m (80-130 feet) tall. The bark is very distinctive, dark brown and knobbly, quoted as resembling Coco Pops breakfast cereal.[4] The tree coppices readily, and most specimens are multi-trunked or appear as clumps of trunks thought to derive from old coppice growth, with some consisting of up to 100 stems of differing sizes.[3] The branching is unique in that nearly all the side branches never have further branching. After a few years, each branch either terminates in a cone (either male or female) or ceases growth. After this, or when the cone becomes mature, the branch dies. New branches then arise from dormant buds on the main trunk. Rarely, a side branch will turn erect and develop into a secondary trunk, which then bears a new set of side branches.
The leaves are flat linear, 3-8 cm long and 2-5 mm broad. They are arranged spirally on the shoot but twisted at the base to appear in two or four flattened ranks. As the leaves mature, they develop from bright lime-green to a more yellowish-green.[5] The seed cones are green, 6-12 cm long and 5-10 cm in diameter, and mature about 18-20 months after wind pollination. They disintegrate at maturity to release the seeds which are small and brown, thin and papery with a wing around the edge to aid wind-dispersal.[3] The male (pollen) cones are slender conic, 5-11 cm long and 1-2 cm broad and reddish-brown in colour and are lower on the tree than the seed cones.[3] Seedlings appear to be slow-growing[3] and mature trees are extremely long-lived; some of the older individuals today are estimated to be between 500 and 1000 years old.[5]
The discovery, on or about 10 September 1994, by David Noble, a field officer of the Wollemi National Park in Blackheath, in the Blue Mountains, only occurred because of his adventurous bushwalking and rock climbing abilities. Noble had good botanical knowledge, and quickly recognized the trees as unusual and worthy of further investigation. Returning with specimens, and expecting someone to be able to identify the plants, Noble soon found that they were new to science. The species was subsequently named after him. Further study would be needed to establish its relationship to other conifers. The initial suspicion was that it had certain characteristics of the 200-million-year-old family Araucariaceae, but was not similar to any living species in the family. Comparison with living and fossilised Araucariaceae proved that it was a member of that family, and it has been placed into a new genus with Agathis and Araucaria. Fossils resembling Wollemia that are possibly related to it are widespread in Australia, New Zealand and Antarctica, but Wollemia nobilis is the sole living member of its genus. The last known fossils of the genus date from approximately 2 million years ago.[8] It is thus described as a living fossil, or alternatively, a Lazarus taxon.
Fewer than a hundred trees are known to be growing wild, in three localities not far apart. It is very difficult to count them as most trees are multistemmed and may have a connected root system. Genetic testing has revealed that all the specimens are genetically indistinguishable, suggesting that the species has been through a genetic bottleneck in which its population became so low (possibly just one or two individuals) that all genetic variability was lost.
In November 2005, wild-growing trees were found to be infected with Phytophthora cinnamomi. New South Wales park rangers believe the virulent water mould was introduced by unauthorised visitors to the site, whose location is still undisclosed to the public.
A propagation program made Wollemi Pine specimens available to botanical gardens, first in Australia in 2006 and subsequently throughout the world. It may prove to be a valuable tree for ornament, either planted in open ground or for tubs and planters. In Australia, potted native Wollemi Pines have been promoted as a Christmas tree. It is also proving to be more adaptable and cold-hardy than its restricted temperate-subtropical, humid distribution would suggest, tolerating temperatures between -5°C and 45°C (23° and 113°F), with reports, from Japan and the USA, that it can survive down to -12°C (10°F). A grove of Wollemi Pines planted in Inverewe Garden, Scotland, believed to be the most northerly location of any successful planting, have survived temperatures of -7°C, recorded in January 2010.] It also handles both full sun and full shade. Like many other Australian trees, Wollemia is susceptible to the pathogenic water mold, so this may limit its potential as a timber tree.
