Walshs Pyramid - An Island in the Sky

Walshs Pyramid - Wet Tropics Photo

Running south from Cairns to at least Innisfail is a tiny rift valley where the Australian continent began to split then changed its mind. The floor of the valley even has some tiny long extinct volcanic hills set into the sea of sugar cane that now spans the valley. Standing alone at the edge of the valley is an enigmatic granite mountain which has a distinctive flora growing on what is effectively an island in the sky.

Walshs Pyramid is almost a perfect cone which rises from sea level to a modest height of 920 m. Every year there is a running race from the centre of Gordonvale, the nearest town to the top of the mountain and back again. The race is the local equivalent of the ‘Tour de France’ and is the highlight of the local calendar. Locals usually win, traversing the 10 horizontal kilometres and 2 vertical kilometre in an hour and a bit. Normal mortals should allow 4 hours return and mortals with small children can even take 10 hours. To explore Walshs Pyramid remotely, use Google Earth or NASA’s worldwind and the following coordinates (-17.1297830405, 145.798856805).

Environmentally, Walshs Pyramid is a strange place, it is desert in the rainforest. Ten kilometres to the south on Mt Bellenden Kerr, the average annual rainfall is 8 m and one of the wettest places on earth. Even the lowlands surrounding the mountains receive 2-4 m of rain per year. Being a steep solid block of rock Walshs Pyramid is oblivious to this high rainfall, the rain runs off as fast as it falls. Walshs Pyramid is also a pointy headed mountain and is less able to reap moisture from clouds by forcing them up and over the top as the nearby mountain ranges do. Still enough rain has fallen on the Pyramid over the eons to bleach the soils and make them too poor for any type of grandiose vegetation. Walshs Pyramid is a misty desert as it often pokes into passing clouds collecting a few precious drops.

Cycas media

Climbing up Walshs Pyramid, it is possible to identify around 4 distinct bands of vegetation with increasing altitude. At the bottom, the introduced molasses and guinea grasses have replaced the native grasses and herbs and it is good to rush through this area to get the to the natural ecosystems above. Once you have arrived at a gully full of cycads (palm-like coniferous plants), you have arrived at the first band. This level is has lowland open forest or savanna vegetation with an understorey of kangaroo grass. Highlights in this area include the cycads and on the exposed rock faces is a succulent leaved plant from the mint family called Plectranthus. Plectranthus is a wild relative of the red coleus of gardens, and like mint it has a powerful smell. The ambience of each level is also different and this level has coarse rough-looking vegetation. In the understorey are tall straw-coloured grasses, shrubs have large leaves, which are often red or yellow when they are being sacrificed to the dry season. Various types of eucalypt tree dominate and can be recognised by their bark. In this area bloodwoods (with fibrous grey tiles of bark) and ironbarks (strong ridges of black bark) dominate with their thin canopies of large hanging leaves. The vegetation is a reflection of the seasonal dryness and deeply weathered soils at the bottom of the mountain.

Boulders in Heathland

The second level is stringy bark forest with a bright green understorey of grass trees and acacias. Grass trees were previously known as blackboys until the age of political correctness, as their flowers looked like a aboriginal spear. This level comes in at an altitude of 250 m and even at this low height, there is a welcome drop in air temperature. Everywhere are trees blackened by bushfire. Far from being an agent of destruction, fire is the gardener in this habitat. It creates two strategies for survival, rise above the fire by becoming a tree, or remain a shrub and regenerate after every fire. Plants that would create a middle storey are simply cooked out of existence. It is this effect which maintains the neat trimmed appearance of the understorey.

Resurrection Plant - Len Webb Photo

Above the 500 m mark are signs of a cooler, moister environment. Black she-oaks form a middle storey in the forest with their soft pine-like needle leaves. In the understorey between the ever present grass trees, various species of heath plants form a dense knee high surface. The colours of the understorey vary from pastels to vivid yellow greens. Only a few species make up the heath and it does not compare to the great heath vegetations of the world and one has to search a little to find botanical wonders. On the rock faces are strange plants that depend on mists for water. One of these plants is called resurrection plant (Borrya septentrionalis) as it withers to a state resembling death, only to become green again when moist conditions return. This plant, which resembles a small pine tree, is an extremely specialised member of the daisy family. Changing from growing mode to endurance modes and back again takes a few days. In between the plant can be bright luminous orange as the plant uses carotene as an internal sunscreen. Despite its spectacular appearance, this plant like most other mountain specialists is almost impossible to grow in cultivation – it is not worth trying.

Clinging to the highest 80 m of the mountain is the most diverse and interesting vegetation on the mountain. Due to the cone shape of the mountain, this is a tiny area. Perhaps it is the only area to be tall enough to reach the clouds. This is a land of bottlebrushes, banksias and daisies. The few trees are nearly all banksias and she-oaks. Many of the species on this part of the mountain simply do not occur at lower levels. Giant rocks rise out of the dense heath. This special habitat is predicted to disappear within two or three decades due to global warming. Global warming makes the air hotter and this makes cloud base higher, which takes away the mists that sustain the habitat.

New Banksia aquilona leaves

Banksia spinulosa flower

Walshs Pyramid is a great mountain to climb and should be on the list of people seeking a rounded out experience of Australia’s tropical environments. The mountain is only about 30 km from Cairns and the best way to get there is by hire car – look for the turn-off on the Bruce Highway after crossing the Mulgrave River. Walshs Pyramid can also be dangerous. The ground is studded with rough rocks and there are a few steep rock faces so wear good footwear. Heat stroke and dehydration are the main threats. In hot weather, you will need about 3 litres of water to climb to the top. I took a friend from a cold country up the mountain on a cold day and because they had not followed instructions and tanked up on water, they got heat stress (even though it was a cold day and I was going slow). I took time to recognise the heat stress which was progressing to the potentially fatal heat stroke. The friend took several days to recover. Another incident that occurred was an eagle swooped on my small child on the summit. Eagles do not eat people but a 3.5 kg eagle striking a 15 kg kid would be ugly. I saw the eagle coming and called my child back to me as the eagle passed over my head.


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