New research, selected for this year‘s Elsevier Atlas Award, suggests that automating the monitoring process of forest conservation efforts in the tropics by employing drone technology could be just as accurate, yet offer substantial reductions in time investment and overall cost.
Tropical rainforests, often referred to as the planet’s lungs, had taken quite a beating during the 15 years between 1990 and 2005, shrinking by about 8% through deforestation, taken up to clear more land for agriculture.
Given the utmost importance of these lush and biologically diverse environments to our planet’s ecosystem, restoring their health is a top priority. Funded through government subsidies and implemented by individual land owners, these large-scale conservation efforts have to be constantly monitored to make sure the forests are replenished with the right vegetation.
This process, however, is labour intensive and costly, which is where drones – or unmanned aerial vehicles – come in.
“It’s early days but drones have great potential for monitoring restoration efforts in tropical forests,” said lead author of the study Dr. Rakan Zahawi from the Organization for Tropical Studies. “We’ve shown that using drones to replace manual labour can reduce the costs associated with monitoring conservation projects. This could result in more people monitoring their land in the tropics, giving us better information about what works and what doesn’t.”
Up until now, the monitoring has been carried out manually by skilled people in possession of specialised equipment, a process that’s not only costly, but oftentimes difficult as many stretches of the land are hard to access. The only alternative, called LiDAR – a remote sensing technology that analyses reflected light – is not much better, setting the researchers back as much as $20,000 per single flight.
In the study, Dr. Zahawi and his team used inexpensive drone-based remote sensing technology, which allowed them to successfully measure the structure of the forest canopy across a series of 1-hectare regenerating fields that were previously agricultural land in southern Costa Rica. The land is part of a long-term tropical forest restoration project.
The drones themselves were equipped with simple 10 megapixel digital cameras and the open-source Ecosynth software package, which processed the pictures, creating a 3D image called a “point cloud” that represents terrestrial vegetation. This setup cost the team $1,500 – less than a tenth the cost of an equivalent flight.
Comparing the results with those obtained via manual efforts, Zahawi’s team found them to be nearly as accurate, with some errors in cases of low canopy.
“There is still some work to do to optimize Ecosynth and make sure measurements are accurate in all situations. However, the approach has real promise in monitoring regeneration,” said Dr. Zahawi. “The reduced cost and labor intensity means that many more farmers will be able to monitor their land, giving us far more data about how best to conserve tropical forests.”
The study was published in the journal Biological Conservation.