WHAT YOU’RE RIDING THROUGH

The purpose of these track notes is to give you some assistance in recognising and understanding some of the features of the country that you are riding through between Cairns and Cardwell.  This is the ride done in 2007, while we usually go through a similar area, each year the track varies to accomodate local conditions - and spice up the life of the organisers and regular riders.

• Geology: the solid matter, including rocks and soil, which determine the composition, structure and physical properties of any particular area of land - The skeleton of the landscape.
• Metamorphic: A sedimentary rock modified by pressure and heat, such as from an upwelling of granite pushing through it or movement along a fault line. Chillagoe marble is metamorphosed limestone formed by the action of fault lines putting pressure on limestone formed from ancient coral reefs. If you visit there you can still see the limestone, with lots of marine fossils, and the marble immediately adjacent to the limestone outcrops.
• Geomorphology: How the shape of a landscape relates to the geology that has formed it, why one area has steep mountains with sharp ridges and another rounded peaks, why one part of a river is straight through a gorge and another meanders across a flat plain - The body on the skeleton; and
• Vegetation: The clothing on the body; and last, but certainly not least;
• The FNQ Wilderness Bike Ride: the observers lucky enough to see the results of million of years of the geological and biological processes that have formed the Wet Tropics.

The whole ride takes place between latitudes 18 and 17 degrees south in the Tropics, that is, in the part of the planet between the Tropic of Cancer (running through Havana, Mecca, Calcutta and Hong Kong) in the northern hemisphere and the Tropic of Capricorn (running through Sao Paulo (Brazil), Madagascar, Rockhampton, Emerald, Longreach and Alice Springs) in the southern hemisphere. This gives the Wet Tropics region its climate with a dry winter and a monsoonal wet season in the summer, with annual rainfalls of 5 metres not uncommon, and the occasional cyclone if ocean temperatures get high enough. If you’re in Cairns a few weeks either side of Xmas you’ll even see the midday sun in the southern sky. The landscape is heavily eroded as a result of all that rain and features gorges, large alluvial plains, river deltas, mudflats and mangroves. All this heat and rain has the expected effect on the vegetation with tropical rainforest merging into wet sclerophyll forest and then tropical savannah as you pass into the rainshadow behind the coastal mountains. The route passes through two major biogeographic regions – the Wet Tropics and the Einasleigh Uplands. The Einasleigh Uplands were formed from vast basalt flows spewed out of a number of shield volcanoes from about 7 million years ago, spreading over the landscape and cooling to form a dense layer of basalt. These flow also created features such as the Undara lava tubes, where still-molten basalt flows drained down riverbeds below the setting crust on top. Later events were more explosive, creating volcanic cones and craters, such as the Seven Sisters around Yungaburra, which are a feature of the Tablelands landscape today.

The complexity and biodiversity of tropical rainforests is very dependent on soil fertility with the most complex and diverse rainforest found where abundant rain falls on basalt soils in areas of high temperatures. Unfortunately these are also the areas most suitable for agriculture, and most have been cleared for that purpose. The soils on granitic and metamorphic rock are acidic and poor in nutrients by comparison, and support a rainforest poorer in both flora and fauna. As these areas of less fertile soils are also of less value for agriculture, they are by far the largest element of the remnant rainforest in the wet tropics.

DAY 1: Sat 22 September - Cairns to Cardwell

The first day is spent in the Wet Tropics bioregion travelling south across coastal plains formed by sediments deposited from erosion of coastal mountain ranges over the last 65 million years. Sea levels have fluctuated dramatically over the last 2 million years, as much of the world’s water was captured by the polar ice caps during the various Ice Ages and then released in interglacial periods. The present sea level is one of the highest on record and the actual size of the coastal plain has varied as the shoreline has advanced and retreated according to sea levels. However, erosion has progressively moved the coastline westwards leaving harder rock masses, such as granite, exposed as mountains and islands. These mountains include Bartle Frere, Queenslands highest at 1622 metres, and Bellinden Ker between Cairns and Innisfail whilst the many islands include the magnificent Hinchinbrook Island east of Cardwell.

The vegetation out the train window varies from mangroves to tropical rainforest with large areas cleared for agriculture, especially sugar cane. A short deviation into the Kennedy National Park 5 km north of Cardwell (turn right on Ellerbeck Road, left on the Bruce Highway for several hundred metres and right to the National Park) is an opportunity to see a range of coastal vegetation communities, and stretch your legs after the train trip from Cairns, on a forest walk (5km loop, 1.5–2hours - Grade: Easy) that traverses lowland rainforest, open woodland and coastal vegetation with a range of habitats from melaleuca woodland and bulkuru swamps to mangrove creeks with boardwalks. This NP is also the home of the famous North Queensland conservationist Margaret Thorsborne who, along with her late husband, donated all of the land they had painstakingly restored to rainforest from farmland, to the park. Their conservation efforts have permanent recognition in the naming of the Thorsborne Track on Hinchinbrook Island. Access to the forest walk is from either the picnic area, or a point along the access road, and don’t forget your mozzie repellent!

DAY 2: Sun 23 Sept - Kennedy to Blencoe Falls

Today’s ride passes through the Kirrama National park and part of the Girringun National Park. On the climb up the range the vegetation changes from dense rainforest to open forest. The large level area at Society Flat was once the centre of a thriving logging industry. The splendid kauris and rose gums scattered throughout this area were the few still left when the area was designated a "beauty spot" in the 1950s. For further information have a look at the EPA website for Kirrama Park Features and Blencoe Park Features.

Observe the changes in vegetation (the vegetation gradient) as you come inland, gain altitude and move into areas with progressively less rainfall and from the Wet Tropics into the Einasleigh Uplands. Watch out for anthills and look at what colour soil they’re made from, this tells you what types of soils and parent rock you’re passing over. White anthills will usually be on granitic clay soils and, when they become red you’ve crossed on to the Einasleigh Upland basaltic soils. There will also be significant changes in the vegetation community as you move from one soil type to another, even in the same rainfall area. But annual rainfall, and its decrease as you cross the coastal ranges, is by far the greatest factor affecting vegetation in this area. Altitude will only have a minor effect, unless frosts become frequent enough to damage vegetation. The vegetation will change from tropical rainforest to savannah open woodland by the time you get to the campsite. The wildflowers, especially banksias and grevilleas, growing on the banks of Blencoe Creek are very attractive. Both these species are adapted to very poor soils with low nutrient levels and can even grow in cracks in the rock.

Another plant species to look out for is the Allocasurina (Sheoak and Bulloak) that grows on poor soils with low moisture holding capacity such as road verges and other sandy areas. Test your eyesight by counting the vestigial leaves that occur in rings around the “needles” on the Sheoak or Bulloak. One of my favourite plants of this country are the cycads, maybe the image of dinosaurs chewing on them makes them more interesting. This extremely ancient group of plants are the sister group to all other living seed plants and look superficially like many other ferns or palms. They were a dominant species in Gondwanaland with fossils found in Antarctica. Fossil cycads are known from China, some 270-280 million years ago, and the group is thought to have arisen from within the ancient seed ferns. The cycads radiated and spread widely over 200 million years ago and have continued as a separate lineage since that time. The Jurassic period of the Mesozoic era, is often referred to as the 'Age of Cycads', as well as being famous for the dinosaurs that ate them, and each other, for almost 70 million years. If you wander down the track on the eastern side of Blencoe Creek to the falls you may see some different types of vegetation that depend on the continual mist arising from the falls for their survival.

DAY 3: Mon 24 Sept - Blencoe Falls to Herbert River Crossing (Cashmere)

Not a long day, with only 37 Km on good quality dirt granite road, so you may want to start the day with an extra 10 km (return distance) of moderate track to the Blencoe Falls Western Lookout, at the point where the gorge cut by Blencoe Creek meets the much larger Herbert River Gorge. The track leaves the granites of the previous day and passes over lateritic soils (red, iron-rich material from heavily weathered rock) and, at our destination for the day, meets the basalts of the lava flows that are not only a major feature of the Einasleigh Uplands but also blocked the original southerly course of the Herbert River towards the Burdekin. Watch the termite mounds for colour changes, even the areas cleared for agriculture, that mark changes in soil type and the different native vegetation that grows on these areas. Further information at the EPA website .

DAY 4: Tues 25 Sept - Rest Day or Herbert River Falls

The waters of the Herbert River, formerly flowing into the Burdekin and dammed up by the Einasleigh lava flows about 7 million years ago, eventually cut into the softer granites that define the course of the Herbert River Gorge, make a sharp left turn at the falls and head east down the gorge towards the coast at Hinchinbrook Island. The falls are in several sections with the lowest section having a 100 metres sheer drop into the gorge. A raft trip downstream from Herbert Falls to Blencoe Creek can easily take a week to cover the distance cycled on Day 3. As at Blencoe Falls, look out for different vegetation dependent on the mist from the falls for its survival. Keep an eye out for the boundary between the granites and basalts and changes in soil and vegetation as you return to our campsite at Cashmere.

DAY 5: Wed 26 Sept - Herbert River Crossing to Innot Hot Springs

The other outcome of the blocking of the Herbert River, which we cycle through the remains of most of the way north to Mt Garnet, was the formation of a large lake that accumulated a lot of sediments before the river eventually cut its way east to the sea. The bed of this former lake is an area of soils significantly richer than most in the area and the focus for many proposals of irrigated agriculture, possibly including cotton. The vegetation on this area is more limited by the rainfall than the soil properties. Near Innot Hot Springs there is also some industrial archaeology at the remains of a large tin dredge. These monstrosities, now banned in all Australian states, floated in a pond of their own making and used to work their way down the alluvial plains of a river, extracting the minerals from the rest of the alluvial sediments and spewing their reject material out behind them. The leftovers from this process are so mixed up, with any organic layer, topsoil and subsoil all mixed together, that they tended to leave a moonscape behind them. Sometimes the subsoil could even cement the rest of the soil profile forming a hard surface layer even more resistant to the re-establishment of vegetation.

DAY 6: Thurs 27 Sept - Innot Hot Springs to Ravenshoe

We leave the Herbert River behind and head across an area of older volcanics into the Atherton Basalts and up the escarpment leading to Ravenshoe, Queensland’s highest town and a former milling town dependent on the timber harvested from the wet tropics rainforest surrounding the town. The transition of the vegetation from savannah to tropical rainforest is one of the fastest rates of change of vegetation communities over a short distance of anywhere on the planet. So keep your eyes open for the change from savannah to wet sclerophyll and then to rainforest. The wildlife also changes, from the kangaroos, wallabies and bustards of the savannah to tree kangaroos and cassowaries.

DAY 7: Fri 28 Sept - Ravenshoe to Tinaroo

The whole day is basically spent on volcanics, at first up and down across the heavily weathered older Glen Gordon volcanics, then the much more recent Atherton Basalts with many volcanic cones scattered across the horizon and beside the road. Changes in vegetation will be due to rainfall patterns, slope and aspect (whether the land faces north, east, west or south). No savannah today, only rainforest and wet sclerophyll forest and lots of agriculture, centred on the rich basaltic soils. So you may as well enjoy some of the benefits of agriculture at Gallos Cheese and Chocolate Factory (coffee, cheese and chocolate as well as meals and snacks), where East Barron Road meets the Malanda-Atherton Road, and the Shaylee Strawberry Farm (icecreams and gelatis and snacks) on the corner of Marks Lane and the Yungaburra-Atherton Road. DAY 8: Sat 29 Sept - Tinaroo to Cairns – The day starts in the Danbulla National Park below Tinaroo Dam travelling across the ancient Hodgkinson formations abutting the Tinaroo granites forming the southern end of the Lamb range and down onto more Atherton Basalt towards Davies Creek. Further information at the EPA Website .

The irrigated agriculture in this area is generally on the basaltic soils, not only because of their richness, but also because of the basic flatness of these more recent basalt flows. A good place to stop for a quality cup of coffee is at Tichum Creek Coffee Farm, opposite the junction of the Davies Creek Road and the highway.

The ride to Copperlode Dam is through the Dinden National Park and passes through both wet sclerophyll forest and tropical rainforest growing on weathered Hodgkinson formation metamorphic rock that surround the granite outcrop of the Lamb Range. The Djabugay Aboriginal people traditionally used this area for ceremonies, painting, and tool making. Examples of their artwork in red and yellow ochre can be seen (access by guided tour) in the Bare Hill Conservation Park within the Dinden NP. Dinden National Park also contains dry open forest and casuarina forest remnants. Many large rainforest trees remain, including kauri pine, red cedar and Queensland maple. A number of birds, such as the eastern yellow robin, the white-cheeked honeyeater and white-naped honeyeater are particularly fond of the wet sclerophyll forest of the park. Endangered northern bettongs are also found in parts of Dinden National Park. These rat-kangaroos, about the size of a possum, feed almost exclusively on truffles (underground fungi). This unique feeding behaviour helps maintain forest health by spreading truffle spores, an essential part of the life cycle of many trees. During the day northern bettongs rest in well-concealed grass nests, but at night you may be lucky enough to see their spritely, bouncy hop as they search for truffles. These unique creatures were once widespread but today only four small populations remain in very limited areas of north Queensland and nowhere else in the world. Researchers also recently discovered southern brown bandicoots residing in Davies Creek National Park, an animal previously thought to be restricted to the wet coastal regions of eastern Cape York. Further information at the EPA Website .

You get one last chance to reward yourself, and you’ve certainly earned it, with a treat in the rainforest at the Lake Morris Kiosk before the downhill run into Cairns and suburbia.

Compiled by Brynn Mathews from personal experience, information on EPA/QPWS website and other websites, August 2007.