But starting up above, rather than digging down below, one of the roughly 60 ongoing projects at Jasper Ridge seeks to estimate ecosystem biomass. This involves cross-mapping data gleaned from the air using light detection and ranging (LiDAR) technology with data from hyperspectral imaging by NASA’s Advanced Visible Infrared Imaging Spectrometer (AVIRIS). Using geographic information systems (GIS) software to combine these datasets, scientists and students can learn infinitely more about biomass than they could before because the data reveal precise details about the plant canopy and the foliage’s biochemical composition.
But it’s not all technology. One morning in summer, biology graduate student Kyla Dahlin and undergraduates Sara Maatta and Chris Fedor, majoring in civil engineering and Earth systems, respectively, set out for a wooded area of the preserve to count and measure trees and shrubs. They were appropriately dressed to discourage the omnipresent poison oak and always dangerous ticks. The previous afternoon, when the satellites of the global positioning system (GPS) are most easily accessed, Dahlin, who is supervising the other two, had used GIS and a stratified random sampling method to pick out what would be the southwest corner of a 20-by-20-meter plot. Within that plot, they would record all trees with a diameter of more than 5 centimeters, noting foliage, the percent of the tree that is alive, presence of disease and type of canopy. In honor of a visitor, they chose a nice clean plot, not too poison-oaky, not too steep: “the most perfect plot we’ve laid,” Maatta said happily. She held the clipboard, jotting down the numbers that Dahlin and Fedor shouted as they measured the circumference of the trees with very cool tapes that automatically divide by pi to give the diameter.
Maatta’s summer project concerns bay laurel trees that host sudden oak death; researchers are not sure the disease is present at Jasper Ridge, though they consider it likely. Fedor is interested in fire prevention and prediction in a chaparral ecosystem, a subject of concern at the preserve. Both students will be studying abroad this academic year, she in Beijing, he in Australia.
They found oak, bay, madrone and coffeeberry trees that day. One bay tree in particular would be useful for Maatta, Dahlin said, as it had five strong stems. A specimen that big for sure would show up in the aerial data in the computer. Once she locates it on the computer, reading the chemical and physical information thanks to the LiDAR, she could create a map of bay trees and then go back into the field to check that they’re actually where the computer said they would be.
“That’s the basics of remote sensing,” Dahlin said.
After they were done with the trees, the group recorded all the shrubs of a certain size, and then the teensy understory vegetation in a 1-by-1 sample plot—even the poison oak.