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2016-12-07. Drones help monitor health of giant sequoias.

posted Dec 15, 2016, 2:53 PM by Alan Gould   [ updated Dec 15, 2016, 2:55 PM ]
By Robert Sanders, UC Berkeley News. For GSS ABCs of Digital Earth Watch chapter 8. Excerpt: Todd Dawson’s field equipment always includes ropes and ascenders, which he and his team use to climb hundreds of feet into the canopies of the world’s largest trees, California’s redwoods. It’s laborious work, but he’ll soon be getting a little help. From drones. ...Since 2010, more than 102 million trees, mostly pines and firs, have died in California 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? In August, 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. 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. ...Dawson is now assessing how best to use the initial data and the drone and camera to answer questions in plant ecology. For the giant sequoias (Sequoiadendron giganteum), which he studies in the University of California’s 320-acre Whitaker Forest just outside Sequoia-Kings Canyon National Park, he anticipates learning a lot more about their physiology than can be achieved by roping onto the canopy. Knowing the leaf area alone is a key advance, since he and his team have been able to model only the trees’ branches and twigs, from which they estimate leaf surface. “If we know how much area is there, I can tell you how many tons of carbon per meter squared per day was fixed by that forest, and how much water was used by that leaf area per day. You can start to get at rates of carbon exchanged between the tree and the atmosphere and then at rates of carbon sequestration,” he said. “These are important numbers for our forecasting models, so we can say, ‘If the climate goes up by 2 degrees, or it gets drier by 10 percent, what the hell is going to happen to that productivity?’ All of a sudden you have power to really measure the pulse of the Earth, which is a really hard thing to do at large scales.”...  http://news.berkeley.edu/2016/12/07/drones-help-monitor-health-of-giant-sequoias/