Australia 2019 – Day 14 – The Gondwana rainforest of Australia

I have spent the morning walking amongst giants. The path I took went down, down, down a deep mountain slope, where giant trees that rise 100 to 150 ft tall make the understory look mysterious and ethereal.

My instincts were right. From a path display I read “Once upon a time, in the mists of a distant pass, primitive rainforests grew in the warmer, wetter world geologists call Gondwana. As that ancient mass drifted north and slowly broke apart, ferns and cycads, ancient pines, primitive flowering plants, and ancestors of animals we know today were set adrift from each other to complete their evolution on separate continents.”

Then, as Australia became more arid, this ancient forest started to shrink and to become isolated in places that remained unusually wet. Ebor Volcano, active 20 million years ago, became one of the last refuges for this unique forest. The volcano was a huge shield volcano that covered 400 km², and weathering over the years transformed it into a series of valleys separated by feeder dikes that became steep barriers across which different tree species had a hard time crossing. This is probably why the eucalyptus forest was unable to invade the realm of the Gondwana forest.

Dorrigo receives a mean precipitation of 72 inches per year, which should allow for enough dry days for us explorers. Well, not for this particular explorer, for I had to tramp through the paths between these giants under a light but steady drizzle. I dressed for the part, with sandals (I am keeping my sachets of salt dry in the car for taking care of the leeches when I come back), shirt, and pants with empty pockets. I don’t have a poncho or umbrella, so I am just going to get wet and change into dry clothes once I am ready to head for the coast. The variety of trees is overwhelming (e.g., yellow carabeen, booyong, strangler fig, and the giant stinging tree that will make your skin blister like poison oak, together with palms, epiphytes, and ferns), as are the varieties of birds, reptiles and amphibians, and small mammals. So far I have not found any hand-size bird-eating spiders, but I had several encounters with Bush Turkeys, which seemed little affected by my presence.

Regarding my Gondwana forest, I am still missing an important part of the puzzle. I am looking for Araucaria antarctica, partly because it is one of the few Gondwana conifers I can recognize, and partly because it would neatly wrap up the story of the breakup of Gondwana. You see, 100 million years ago Gondwana was a large continent that extended almost from the equator to the south pole. Along its higher latitudes there was a conifer forest that extended from South America, through Antarctica, and into Australia. When the three landmasses fragmented off Chile carried with it its population of Araucaria, which now survives in a tiny portion of the Chilean coast, in the Coastal Fog Forest ecosystem. The ones in Antarctica became extinct as this landmass moved south into a polar position and the Oligocene glaciation started. Finally, the Australian Araucarias got stranded in the very temperate rainforest I find myself in. … After much looking around I sighted an Araucaria on the other side of the valley, so I am calling it good (the problem is that Araucaria is a type of giant redwood, so the European settlers targeted it for extinction by logging). Later I found a couple of ornamental ones, so I am pretty certain a few have survived.

At lower altitude, toward the Bellinger Valley, there is grove of Sydney bluegum, blackbutt, and tallowwood where some of the trees are over 1,000 years old!