In one of the last posts, you had a chance to read about Marco’s trip to temperate rainforest. Now we move to the other side of the Pacific Ocean, where is located the world’s oldest rainforest. The region referred to as the ‘Daintree Rainforest’ covers an area of approximately 1200 square kilometres and extends from the Daintree River, north of Cooktown and west to the Great Divide. It is the oldest intact lowland tropical rainforest in the world, thought to be around 180 million years old. In the same time, it represents the largest block of tropical rainforest in Australia. Before big firest started in the Land Down Under, I had a pleasure to visit this fascinating and diverse eco-system on the Earth and in this blog post, I would like to share with you what I have seen and what I have learned from this amazing journey.
Back to beginning
Around 180 million years ago, in the age of reptiles, ferns, cycads and conifers, a supercontinent – Pangea broke up (see photo below). This is mainly the reason why Daintree and Wet Tropics, in general, are considered to be the oldest continually surviving rainforest in the world as they contain plants inherited from the ancient stock of Gondwana.
“For a lot of the (Pandora) jungle over-views, I used photos that I had taken from the Kuranda Skyrail near Cairns, Australia” – Dylan Cole, Designer, Avatar
>>READ MORE: Do you know what is the oldest and rarest tree in the world? You never find out!
Earth’s evolutionary history
The Wet Tropics represent a major stage of the Earth’s evolutionary history due to almost complete record of the evolution of plant life. The plant diversity and structural complexity here is unrivalled anywhere else on Earth. For instance, Daintree includes 12 of the 19 primitive flowering plant families and represents the origins of many of Australia’s most familiar flora.
Ice then, fire now…
When I read the history of the continent it resembles me a bit of what is happening currently with Australia and fires. Around 120 thousand years ago, consecutive ice ages occurred in the Land Down Under. During this time, the rainforest contracted and expanded and animals either adapted to the conditions or disappeared. One could say that the mass extinction of animals and plants for Australia is nothing new, but the same happened in other continents as well. Including Europe where the last ice age occurred only around 10 thousand years ago. I think it is worth to remember about the history and the time scale that shapes our planet the most.
>>READ ALSO: Trees on the Moon
Due to ice ages, rainforest and whole Daintree region became a refuge for ancient and unique plants and animals. The wet tropical rainforests of North-East Queensland, which represent less than 0.1% of the Australian continent by area, contains roughly 40% of Australia’s bird species, 35% of Australia’s frogs, marsupials and reptiles, not mentioning ca. 65% of Australia’s bat and butterfly species.
What is Cloud Stripping and how much water rainforest receive annually?
Rainforests help to regulate the water cycle and can influence the local climate and are an important source of food and medicine. The mountainous areas of the Wet Tropics World Heritage rainforest can receive up to 8 meters of rain annually, the majority of which falls in the summer months between December and March. When it rains, water filters down through the leaves to the debris of the rainforest floor and back into the soil. The rainforest plants absorb the water they require for their own needs while the excess runs off the land feeding creeks, streams and rivers. Any remaining water is filtered through different soil layers, before reaching the groundwater level. Interestingly, during the winter Dry Season, these groundwater reserves are slowly released back into the soil, keeping the rainforest plants alive and streams running year-round – even without rainfall.
>>READ ALSO: Forests on the Devil – Asinara National Park
Cloud Stripping is a vital source of water for the rainforest that can take 30% to 40% of their water requirements directly from the clouds – even when it isn’t raining. Misty clouds often cling to the forest canopy at around 600 meters above sea level, settling on leaves and stems and trickling down tree trunks to the forest floor.
Some interesting animals and plants in lowland tropical rainforest
Ferns
Ferns dominated the planet hundreds of millions of years ago and are present up to this day. Did you know that ferns invented leaves? Yes, it is true. Using their leaves as solar panels, they capture and store the sun’s energy as food. Ferns also developed a system for the upwards movement of water and nutrients from the soil and a root system to reach less accessible sources of water, providing greater stability – particularly for larger species. The largest frond in the world is King Fern, which can be up to 7 meters long. This species is a relic from 320 million years ago that is still found in the Daintree rainforest today.
King of the jungle!
Agathis robusta (syn. A. palmerstonii), the Queensland kauri pine or smooth-barked kauri (see photo on the right) stood is known as an “emergent” species as it grows tall and fast, punching through the rainforest canopy where it spreads out like an umbrella and blocks the sunlight reaching those plants below it.
>>READ ALSO: What do think you know about forests in Syria?
This tree is amazing and you should instantly notice what is so exceptional in its trunk. Usually, all the trees in the tropical rainforest are covered by different kinds of lianas and have low branches. But Queensland kauri pine has no low branches and has a smooth self-shedding bark, what prevents the likes of vines and other plants from growing up it and competing for light. But also this strategy of self pruning and bark self peeling reduces the risk of uprooting during occasional cyclons due to reduction of wind resistance. With the origins of these trees dating back more than 200 million years, it’s an adaptation that has served them very well.
Kangaroos in the trees
Millions of years ago Tree Kangaroos evolved from their possum-like ancestors and left the treetops to graze the open grassland. However, some returned to the safety of the rainforest branches and remained there. One of such examples is Lumholtz’s Tree Kangaroo (Dendrolagus lumholtzi), which is the smallest of all tree kangaroos.
Southern Cassowary
Cassowaries are considered a key species in maintaining the diversity of rainforest trees. Thanks to them large rainforest fruits can be dispersed as they are the only species that can carry large-seeded fruits over long distances. Protecting cassowary habitat is very crucial but also careful drive around this part of Queensland is very important as these birds are often killed by cars.
I almost hit one as they are not the most clever birds in the world. So drive carefully 🙂 as these birds are quite difficult to spot (see photo below).
For Visitors: Skyrail + Kuranda Scenic Railway
If you wish to get a unique rainforest experience through Australia’s World Heritage-listed Tropical Rainforests, then I highly recommend you to take a one day trip to Kuranda. Together with my family, we took first a Kuranda Scenic Railway and then on the way back we took a Skyrail. It was an unforgettable experience for all of us.
Main photo: Daintree Rainforest. Author: Rafal Chudy
Oh my… I thought the rainforest of Borneo is the oldest.
There is no evidence that Daintree is 180 million years age. It is a guess based on some ancient species being in the forest that started back before Australia was split from Antartica and New Guinea. Many of the trees in the forest started life on the planet 60 million years ago and many evolved much later. Remember too that with ice ages most of these rainforests disappeared for many years and there is no evidence whatsoever that the Daintree existed continuously over time – it is highly unlikely that it did. Trees sprang from pockets that survived heat and ice periods. Further, forests elsewhere in north Queensland have a similar diversity of species and most likely existed for the same time – Daintree is far from unique apart from its enthusiastic advocates who gild the lily at times.
I don’t think there is any inference that the Daintree Rainforest survived in its entirety during ice ages. They undoubtedly shrank, and also expanded again during wetter periods. However the fact that plants from a range of primitive plant families (as signalled by the fossil record) to me signals that the contracted rainforest remained large enough to sustain considerable biodiversity.