I won’t reiterate all of this well-known story, to me reminiscent of the novels by Jules Verne: a chance discovery, in a hidden Australian canyon, of a so-called living fossil. What the ranger David Noble found on September 10, 1994, upon rappeling down into a narrow sandstone gorge, was an eerie sight, totally unfamiliar.
It was unreal, or rather surreal, as if he had entered a Douanier Rousseau painting. Or, to try and express his surprise, it resembled the feeling one has upon first snorkeling over a coral reef: awe and wonder, from having just entered a different world, as in a dream.
David Noble’s find turned out to comprise three copses of tall trees — their trunks rise up to 40 m in height and measure up to 1.2 m in diameter—, which genetic studies showed to be reproducing mostly by self-coppicing, i.e., sprouting offsprings from their roots. The oldest was at least 1,000-years- old.
Their ecological niche was a moist rainforest environment where these conifers were surrounded by coachwood (Ceratopetalum apetalum), sassafras (Doryphora sassafras), and a variety of ferns and trees of the eucalyptus family. The aspect of the trunk is unusual, a knobbly, dark brown bark. The branching is characteristic in that nearly all the side branches do not show further branching. Each branch either terminates in a cone (male or female) or ceases growth after several years. Afterwards or with maturity of the cone, the branch dies. Dormant buds on the main trunk give rise to newer branches.
The seed cones, that mature 18–20 months after wind pollination, are green, 6–12 cm in length and 5–10 cm in diameter. At maturity they crumble down and release small brown seeds. They bear a wing for wind-dispersal.
The male (pollen) cones are slender conic, 5–11 cm long and 1–2 cm broad and reddish-brown in color. They are found lower on the tree than the seed cones.
The leaves, in spiral arrangement on the shoot, are twisted at the base and they make two or four fla_ened rows. Each leaf is flat linear, 3–8 cm long and 2–5 mm broad. Young leaves are a bright lime-green. Adult leaves are a more yellowish-green.
The headlines in science popularization magazines made a point out of these tall trees having been contemporary with dinosaurs. How come then that this species had somehow survived the impact of the meteorite that, 66 million years ago, wiped out not only dinosaurs, but also a very large number of biological species?
Part of the answer is the hardiness of this tree: the Wollemi tree can undergo temperatures from – 5 to 45°C (23 to 113°F) and has withstood trials in freezing weather. Like any plant, it loves water, nutrients, and light, but it can also withstand their temporary absence.
Location is the other part of the answer. The family Araucariaceae dates back to the Jurassic and Triassic. In the northern hemisphere, most of its members were wiped out by the meteorite. The Wollemi trees lived in the Southern hemisphere, at a great distance from the Chicxulub impact, off present-day Yucatan. Their fortune was that it was winter and they were hibernating, in a dormant state.
This plant is a relic from Gondwana. As one may recall, this was a continent that afterwards plate tectonics moved and dismembered. It comprised present-day Antarctica, with a different location and climate than today — it then had an abundance of plant species —, Australia, New Guinea and New Caledonia. Thus, each of these land masses also preserves other relics from the Gondwana flora.