Rainforest Rainbows

Skyrail Nature Diary: March 2010

March heralds the end of the wet season, in the Wet Tropics Rainforests of Cairns and Tropical North Queensland, making this your last chance to see many of our waterfalls and rainbows in all their glory.

The Wet Tropics Rainforests has two distinct seasons, the 'wet' and the 'dry'. Over 60% of annual rainfall arrives during the 'wet', which is from December to March, making this the best time of year to witness the beauty and might of our rainforest waterfalls, including the 260m (853 feet) Barron Falls.

Interestingly, it is believed that less than half the total rainfall directly penetrates the rainforest canopy to the forest floor. The canopy acts as an umbrella, diffusing the rain drops through its closely knitted ceiling of leaves.

In the rainforests, some leaves have evolved 'drip tips', pointed ends that collect the rain and help to channel the water off the leaf, downwards.

The rainfall slides between the leaves of the canopy, down the tree trunks, where it can be absorbed directly by the tree bark, or captured by the epiphytic basket and birds nest ferns that perch along the trunk and braches of their host trees.

Some of this rain will evaporate before it reaches the forest floor, adding to the already humid conditions of the forest, while the remainder will make its way to the forest floor, where it will form steams, flow down mountain gullies and join creeks and rivers, before flowing over waterfalls and making its way out to sea.

Along the way, it creates perfect breeding conditions for rainforest frogs and growing conditions for moisture-loving plants such as ferns, mosses and lichen.

The 'wet' is a wondrous time to visit the Wet Tropics Rainforests and it is about to end for another year, so don't miss your chance to travel through the rainbows and past the waterfalls on Skyrail Rainforest Cableway this month.

Note: Did you know that the Bellenden Ker Range, a 30-minute drive south of Cairns, is one of the wettest places in Australia? In 2006, Bellenden Ker's Top Weather Station recorded 9,850mm of rainfall, which was the highest recorded rainfall total in Australia for that year. Of course, rainfall varies from year to year and in 2009, that same station recorded just 7,440mm of rain (24 feet).

Rainfall also varies according to altitude: with Bellenden Ker's Bottom Weather Station receiving 2,385mm less rainfall than the Top Station, in 2009. Despite this, the Bottom Station was still the second wettest spot in Queensland that year. Putting this into some perspective, the driest area in the state was Birdsville Airport, which only recorded 115mm of rainfall, a massive 7,325mm less rain than Bellenden Ker.

Rainforest stream picture courtesy Wet Tropics Management Authority. Barron Falls picture, courtesy of and taken on Skyrail Rainforest Cableway.