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Liebherr’s jungle giant celebrates 20th birthday

For 20 years, a tower crane has been fundamental to a global, scientific network studying the world’s great rainforests. The Liebherr 91EC enables scientists to study everything from the forest floor to the tops of the canopy.

Australia’s longest-standing crane celebrated its 20th birthday in November. While most cranes of this size spend their working lives in construction and industry, this 47-metre-high crane spends its days carrying researchers from the Daintree Rainforest floor to the canopy and above.

Twenty years ago, a Liebherr 91 EC freestanding construction tower crane was built in the heart of Daintree Rainforest. The crane is central to the James Cook University’s Daintree Rainforest Observatory (DRO) at Cape Tribulation, as well as contributing to Australia’s National Collaborative Research Infrastructure Scheme through the Terrestrial Environmental Research Network (TERN).

The canopy crane offers researchers access to the entirety of the rainforest – from the ground to the atmosphere above the canopy. Adding to the soil and ground-water monitoring capabilities of DRO, the crane makes this a true critical zone observatory monitoring the mechanisms and functions of the ecosystem critical to life on earth – soil, biota and atmosphere.

Skilled technicians provide precise control over the canopy crane’s personnel box, giving researchers access to every layer of the Daintree’s irregular canopy. Power and data connections are available for equipment installations. The research uses automated sensors and a wireless data network to closely monitor a hectare of rainforest.

Within the arc of the crane, all 680 trees with a DBH (diameter at breast height) greater than 100mm have been identified and tagged. This covers 82 species across 33 different families.

The university has installed a range of monitoring instruments to track the fundamental movements of resources in the ecosystem. These include dendrometers to monitor tree growth, sap flow meters that measure movement of water and nutrients vertically in trees, soil moisture at a range of depths, bores for measuring the ground water level and recharge, a stream flow gauge, leaf litter traps that follow the fall of nutrients back to the surface, weather stations and cameras to track seasonal changes in ecosystem processes throughout the survey area.

“Thanks to our operator’s skill and precision, researchers travelling in the crane’s personnel box are able to access every level of the forest,” JCU’s Dean of Research Professor Andrew Krockenberger said.

“In recent years we’ve added automated sensors and a wireless data network, allowing researchers to closely monitor a hectare of rainforest, from the soil, up through the forest and to the atmosphere above.

“In a major research project underway, Associate Professor Susan Laurance is creating a mini-drought, to investigate how trees in the wet tropics are likely to respond to longer, hotter, more extreme dry seasons that are expected as a result of climate change.”

Professor Krockenberger said the crane and the DRO were part of a global network.

“Our changing climate and the myriad other threats to natural ecosystems mean that it’s more important than ever to build on our understanding of how forests work, and how they might respond to changing conditions,” he said. “The Observatory is used extensively by local, interstate and international researchers in work that is adding significantly to our understanding of tropical rainforests.”

Research conducted at the DRO has included studies of carbon and water fluxes, tree physiology and ecology, and vertebrate and invertebrate biodiversity.

Community leaders and scientists celebrated the significant birthday at the crane site in November.

“It’s a chance for us to thank everyone who has supported us in establishing and expanding the facility – first with the crane, and later the laboratories, teaching space and accommodation that have made this a world-class research facility and a spectacular classroom in the rainforest,” Professor Krockenberger said.

“We are particularly pleased that Andrew Esquilant of Liebherr Australia is able to attend the celebrations and see one of their cranes doing work that its makers probably never imagined.”

Not long after it was installed, the crane was struck by a Category 3 cyclone. Tropical Cyclone Rona severely battered the surrounding forest but the crane remained standing – and was soon being used by scientists who took advantage of the opportunity to study rainforest regeneration.

Researchers access the personnel box at ground level. Movement of the personnel box to a specific position requires rotation of the entire jib in a horizontal plane until the jib is above the position desired. The trolley is then moved along the jib and the hook and personnel box are lowered to the desired position.

The canopy crane is manoeuvred by a qualified tower crane operator using a custom-built remote control. The crane operator has total responsibility for the safe operation of the crane including monitoring occupant safety, load limits and weather conditions.

The crane operator has the final say regarding whether it is safe to conduct crane operations. The personnel box can accommodate up to four people, including the crane operator, with a maximum working load limit of 300kg. All occupants are required to wear a fall arrest harness and lanyard, which is attached to purpose made anchor rings. A small shed is provided at the base of the crane for users to be fitted into their harnesses and to prepare required research equipment.

Australia’s James Cook University is committed to creating a brighter future for life in the tropics and worldwide through graduates and discoveries that make a difference.

The crane at the JCU DRO is putting scientists into the tropical treetops, opening up Australia’s forests to research and bringing the power of research and engagement to bear on the issues of great significance. With continued support from partners, industry can look forward with eager anticipation to the next 20 years of innovative research.

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