High-tech eyes in the sky help scientists understand fragile ecosystems

High-tech, remote imaging developed for the military has become a powerful tool in the hands of scientists studying the health of natural ecosystems.

The technology allows scientists to assess forests and coral reefs from satellites and from specially equipped aircraft that can get an even closer look — down to individual branches of trees.

On board these custom-built aircraft is a system of instruments called ATOMS, which stands for Airborne Taxonomic Mapping System.

Greg Asner, principal investigator at the Carnegie Institution’s Global Ecology Lab at Stanford, helped develop this ultra-high-resolution imaging system — work that won him the 22nd Heinz Award in the environment category.

“ATOMS is comprised of a suite of instruments that work together,” Asner explains. “One of the instruments is a laser scanning system. We fire laser beams out of the bottom of the plane, and those lasers interact with the land, the trees, whatever we’re flying over. Those lasers give us a three-dimensional view of the ecosystem: How tall are the trees? What's the architecture of the branches? It tells us about even the leaf-level architecture — and then we have other instruments that work with [the lasers].”

These include an imaging spectrometer that uses sunlight reflected off the tree canopy to measure the chemical composition of individual trees, and high-resolution cameras that act as a kind of reference that collects all the background information about data the aircraft gathered that day, Anser says.

So far, Asner and his team have focused their work on the biomass of forests. They measure how many species per acre are part of the forest, how much water is in the tree canopy, nitrogen levels — all the things that indicate the health of the forest.

Recently, the team has been conducting similar work on coral reefs. “We just had a breakthrough last year where we figured out how to fly over a coral reef and digitally remove the seawater so that we exposed the bottom and we were able to understand the health and the condition of the corals that live below that sea surface,” Asner explains.

Asner says he and his colleagues have mapped areas all over the planet, but place particular emphasis on regions that are undergoing rapid development. “[O]ur science and our technology can play a role in mapping the attributes of a forest in a way that allows for better decision-making in the context of development [or] in the context of, say, putting in new agricultural fields and avoiding areas of high biodiversity.”

All of this highly detailed mapping has revealed what Asner calls “the good, the bad and the ugly.”

“We found extremely high biological diversity — lots and lots of species coexisting in patterns that were unknown to science,” he explains, “so, the good thing is that we were able to unveil those landscapes and see them for the first time.”

“The bad would be when our work reveals that there are, say, illegal gold miners in a region,” he continues. “The ugly is some of the hardest work we do, which is mapping regions in preparation or in consultation for the effort to mitigate losses as climate change proceeds. I call that ‘the ugly’ because those are really hard problems to crack. That science is in its infancy and we're still trying to figure out how to do it.”

Asner says the project’s “most operational, mature type of science” is its ability to measure how much carbon is stored in a forest.

“Today, we're able to fly over a forest and relatively quickly get an estimate of the carbon stock, and that's important for a lot of reasons,” he explains. “One, carbon is a great metric of the health of a forest. A forest with lots of carbon stored is generally a forest that's in good shape. But also, it's a critical component of the climate change mitigation efforts of state and federal governments. They want to be able to store carbon in forests rather than it being in the atmosphere as carbon dioxide, so they want to know how much they're storing in these forests today, and they want advice, consultation and guidance on how they might store even more carbon in their forests in the future.”

NASA wants to put some of this technology into orbit, Asner says. He believes the laser technology may be available on the International Space Station within the next 18 months or so.

“The chemical mapping is the most critical at this point, in terms of mapping the health of coral reefs and ecosystems in general, on land and in the sea,” he says. “Those technologies are of interest to organizations like NASA and the federal government.”

This article is based on an interview that aired on PRI’s Living on Earth with Steve Curwood.