An aerial eye on the forest

Author: Andrew Avitt

Gathering a deep understanding of a forest, from the roots to the treetops, was once only possible after months of walking the landscape. But soon U.S. Department of Agriculture’s Forest Service employees could be using their thumbs and a mechanical friend to help get the job done in days.

Meet the Vision Aerial Switchblade. With a top speed of 62 mph and weighing in at just over 7 pounds, this uncrewed aerial system or UAS can fly over a landscape while gathering data on the terrain. It sees the big picture and the little picture — from the broad health of the forest, down to specifics on an individual tree — which informs land management decisions.

The Vision Aerial Switchblade can be fitted with a mirrorless camera. This camera takes a series of overlapping photos which can later be processed as a 3D image. (*USDA Forest Service photo by Andrew Avitt*)

“We can use uncrewed aerial systems in many ways,” said Chris Brenzel, a UAS specialist with the Forest Service. “In this instance, we’re using it to map the vegetation to generate 3D models of the forest, which gives us specific data on the width and height of the trees, the health of the trees, canopy cover, and the size of the crowns. From that, we can determine which trees are dead, which trees are struggling, and which trees are healthy to better plan how to treat these areas.”

Brenzel is one of many UAS pilots assigned to survey a proposed project area of 58,000 acres on the Inyo National Forest surrounding Mammoth Lakes, California. It’s one of several projects that coincide with the Forest Service’s national strategy to confront the wildfire crisis, protect communities, and improve resilience in America’s forests. (Leer en español).

The Power of Data to Reduce Wildfire Risk and Support Forests

The Eastern Sierra Communities and Climate Resilience Project has two main objectives — to reduce wildfire risk to residents and to increase forest health and resilience.

Nathan Sill, an ecosystem services staff officer for the Inyo National Forest, coordinates the information gathering and planning for the project.

“We want to reduce wildfire risk to the town of Mammoth Lakes and associated infrastructure, as well as restore healthy forests and provide for long-term resilience. So, we are planning to reduce the density of fuels immediately around the town. Then, as we move away from that community, those treatments become more in line with forest resilience,” said Sill.

The Switchblade’s big brother the FVR-90, a fixed-wing drone has the capability of flying around the entire perimeter of a wildfire, updating maps and providing real time intelligence to firefighters. (*USDA Forest Service photo by Andrew Avitt)*

The UAS data will enable ecosystem staff officers like Sill to identify overstocked areas of forests, where too many trees have made stands susceptible to drought, disease and wildfire.

That data helps determine which land management treatments are needed to remove vegetation, such as mechanical thinning or prescribed fire.

An aerial view of the wildland urban interface near Mammoth lakes, California. (*USDA Forest Service photo by Harry Oh*)

“This technology has the potential to provide much higher resolution data for us to use, and it also allows us to share that data visually with the public,” said Sill. “As this technology becomes more reliable, and we become more efficient with collecting the data and using it, this will be a game changer for forest management.”

An Efficient, Safer Perspective

The efficiency and the safety benefits of this emerging technology can’t be overstated.

“It would take months and many, many people going out to survey the same areas that these drones have flown in a few weeks,” said Brenzel. “In the future, we could fly 150 to 200 acres a week and get that mapped and modelled. That’s a force multiplier and frees people up to do other projects and actually implement them.”

From a safety perspective, UAS enables employees to observe, from a distance, dangerous areas such as steep terrain or locations with standing dead trees, known as snag patches.

Chris Brenzel, UAS specialist, keeps a watchful eye on his aircraft as it carries out an automated flight plan collecting data on the surrounding forest. Right: A thumb controls an uncrewed aerial system over the Inyo National Forest near Mammoth Lakes, California. (*USDA Forest Service photos by Andrew Avitt)*

“There are a lot of snag patches around here from beetle kill and drought,” said Brenzel. “In the past, we’ve had firefighters and other employees killed and injured by trees. [With UAS] we’re not putting our employees in danger just to survey these areas.”

The Forest Service continues to explore even more uses for UAS. Their data is assisting with forest health projects, prescribed fire, wildlife surveys and wildfire suppression.

Brenzel has worked in federal land management for nearly 30 years, from the Bureau of Land Management and the National Park Service to the Forest Service. He’s seen the adoption of UAS expand exponentially.

“We’re really finding a lot of cases where we can mitigate the risk to our employees and pilots and still meet the mission,” said Brenzel. “We’ve seen 300% growth in the three years basically since the program was stood up, but it takes time. We have to train employees; we have to get equipment. But it’s increasing. Because if we can get that data, we can keep our people safe and we can do our jobs better.”