Researcher tests drone to help monitor giant sequoias

Todd Dawson, a professor of integrative biology and environmental science, policy and management at the University of California, Berkeley, has teamed up with Parrot SA, a company that builds flying robots, also known as drones, to test new research tools as a way to monitor the Sierra Nevada's giant sequoias.

Since 2010, more than 102 million trees, mostly pines and firs, have died in California on the U.S. west coast because of drought, 62 million in 2016 alone.

Why are pines and firs succumbing, but the thousand-year-old sequoias surviving, and will that continue into the future? Dawson said the need is urgent to find out how California's redwoods, the world's largest trees, utilize water and sunlight and predict how they will deal with a warmer earth and changes in water supply.

He and Gregory Crutsinger, a plant ecologist and head of scientific programs at Parrot, performed the first test of a drone, a quadcopter, equipped with a state-of-the-art multispectral camera that takes photos in red, green and two infrared bands in August. Called the Sequoia, the camera works like more expensive satellite and airborne sensors, measuring the sunlight reflected by vegetation in order to assess physiological activity or plant health.

"Before, a team of five to seven people would climb and spend a week or more in one tree mapping it all around," Dawson was quoted as saying in a news release from UC Berkeley. "With a drone, we could do that with a two-minute flight. We can map the leaf area by circling the tree, then do some camera work inside the canopy, and we have the whole tree in a day."

After the data and photos were stitched together by a software program, Dawson and Crutsinger ended up with a three-dimensional representation of the foliage that his team had never seen before - information that will be used to determine how much carbon the tree takes up each day and how much water it uses, the basis for assessing what might happen with higher carbon dioxide levels in the atmosphere and less water on and in the ground.

"With repeat flights you can watch a forest grow without ever actually measuring any trees in the forest," Dawson said. "I think drone technology holds a lot of promise to do some very innovative science over time and in three-dimensional space with a relatively cheap tool. It is really pretty amazing."

While assessing how best to use the initial data and the drone and camera to answer questions in plant ecology, Dawson doesn't plan to give up climbing trees. Some data will still need to be captured in the tree tops, if only to connect drone observations with tree physiology and ecology. Endit