To understand whether a rainforest is healthy, recovering from human disturbance or cyclone damage, or in need of management, first, you have to measure it. But that’s much easier said than done.

 “We have to literally crawl on our hands and knees in really quite inhospitable environments,” says Andy Marshall, Professor of Conservation Science at the University of the Sunshine Coast. “We get stung, we get very, very sweaty... we get covered in March flies.” 

The work of measuring a disturbed rainforest is painfully slow, uncomfortable, and often imprecise. In dense, cyclone-damaged forest, where tangled vines choke regrowth and visibility is limited, even moving a few metres can be a challenge, let alone collecting reliable data. 

Still, it’s essential work, helping to inform when and where researchers need to intervene to help forests recover, and the role climate plays. 

“Forests are hugely important globally. They are essentially the lungs of the planet,” Andy says. 

“Unfortunately, many forests have been heavily disturbed and they've lost their canopy… the trees have been cut, or knocked down by increasingly intense cyclones, and in those cases, we need to understand how healthy they are in order to decide how to manage them.” 

This is where the idea for TruForest was born, a new project aimed at transforming how Australian rainforests are monitored, led by UniSC in partnership with five other universities in Australia and Europe, and with ArborMeta, Airborne Research Australia and members of the NASA GEDI Science Team.

“We called it TruForest because what we're trying to do is get a true measure of the forests,” Andy says. 

“These days we can employ different levels of technology, and this project is about developing a laser scanning network for Australian rainforests.”

The TruForest project grew directly out of the challenges encountered during Andy’s ongoing FoRCE (Forest Restoration and Climate Experiment) project at UniSC’s Forest Research Institute, which focuses on understanding how forests recover after disturbance, particularly in cyclone-affected and heavily logged tropical systems. 

It was clear that in many disturbed tropical forests, especially in Australia’s Wet Tropics, recovery wasn’t happening as expected. Vines were dominating and preventing tree regrowth. But without better measurement tools, it was difficult to quantify that process or predict outcomes.

The technology at the centre of TruForest is LiDAR – light detection and ranging – which allows researchers to map forests in three dimensions using laser pulses.

“LIDAR is essentially measuring with lasers,” Andy says. “So we're beaming millions of beams of light into the forests, and then we're measuring them as they as they come back and hit the lens, which gives us a three-dimensional image of the forest. And from that, we can extract things like the size of the trees and the numbers of the vines that are on those trees, and other measures about the structure of those forests.”

The potential gains of using LIDAR technology are significant. What currently takes days of fieldwork to survey a tiny area by hand could be done far more efficiently – in just an hour or two. 

“Finding a way to measure these places more efficiently, like with lasers, will save us a lot of time, give us better accuracy… and save us a lot of pain,” Andy says. “If we do it above, by drone or airplane, we can cover thousands of hectares in a day.” 

UniSC research into the impact of vines spans multiple regions – including Northern Australia, Tanzania in East Africa, as well as sites in Colombia and Vietnam – because, as Andy explains, tropical forests all over the world respond similarly when they're disturbed.

When large trees are lost, whether to cyclones or logging, light floods the forest floor, triggering rapid growth from faster-moving species, like vines, which move in and can take over. 

In Australia’s Wet Tropics, the long-term impacts of Cyclone Larry and Cyclone Yasi are still visible more than a decade later.

“The forests are still in a very similar state to what they were after those cyclones hit – they’ve been taken over by vines which are smothering trees and stopping the forests recovering,” Andy says. “In terms of absorbing the impact of climate change, it's huge because we haven't got those big trees that are able to store that carbon and absorb the impact of fossil fuel releases.”

Even so, the response is not as straightforward as going in and removing the vines.

“People living and working in these areas may think the vines that are smothering the forests need removing, that they're a pest, but sometimes they're helping those forests too because they are preserving microclimates and protecting them from things like strong winds or fire,” he says. 

“We need to find the balance.”

A key aim of TruForest is to provide the data needed to make those decisions more precisely.

“By doing this work, we hope to try and understand how to define a forest that's not going to recover, and therefore what management intervention can take place,” Andy says. “Things like vine cutting or better security for these sites to help them recover.”

To support that goal, the project is also focused on harnessing new technology and making it more accessible. “We're buying equipment that is going to be spread across four Australian universities… which will be open access for others to use, so we can survey more forests.”

This includes both ground-based and aerial systems.

“We've got a terrestrial laser scanner which sits on a tripod, we've got another laser scanner which sits on a drone, and both of them allow us to look at forests in different ways,” Andy says.

And beyond these newly purchased scanners now housed at four Australia universities, the project will also gather LiDAR data from the same sites using aeroplane and satellite LiDAR data.

Yet even with new tools, some of the hardest, densest environments remain difficult to capture. 

“We need to understand how on earth to measure these places that are so inhospitable, and it might take years to get there… but it will certainly save us a lot of pain,” Andy says. 

Ultimately, Andy says his most important message is we need to understand before we act. “Forests need help, but we don't understand everything about them, so this project will help us determine where and when to manage forests,” he says. 

“We’ve got big things to understand that only science can help with, and in the meantime, we shouldn't be too rash in how we treat those vines.”

This caution is warranted, considering the immense ecological value of these environments. 

“Tropical forests are the areas of the highest biodiversity in the world – they've got more species than anywhere on the planet, so they're really important for wildlife,” Andy says. “It’s what drove me in all of this to begin with… I'm a real lover of nature and animals and plants and to see these places disappear would be devastating.”

Andy says there are plenty of opportunities for students and early career researchers to get involved, from field work to analysis of global data, and as the project expands, so too will the opportunities.