|Jessie Young-Robertson is researching when trees have the lowest moisture|
content, and how harvesting them at the right point could shorten the drying
time. UAF photo by J.R. Ancheta
While studying how trees take up snowmelt and rainwater, Jessie Young-Robertson noticed dramatic seasonal variations in the water content in the trees, particularly in deciduous trees like birch and aspen.
Most of her research was undertaken between March and September but last year, she extended her research through the winter —and made a surprising discovery.
|This three-pronged device measures water content in trees.|
UAF photo by J.R. Ancheta
She knew that trees dropped moisture in the fall. “The surprise was how much and how fast,” she said.
The finding could be significant because fall is a popular time to harvest firewood. Depending on the when the trees are harvested in the fall, the wood could be very wet or much drier.
Further research is needed, but she believes that the information being collected may hold a key to reducing wintertime air pollution in Fairbanks caused by residents burning green firewood.
“You can let the trees do a lot of the work of drying the wood for you,” she said.
The technology Young-Robertson used to measure the water content in trees has evolved since she started her research in the woods northeast of Fairbanks.
She used to walk or ski to her research plots in the Caribou-Poker Creeks Research Watershed, off the Steese Highway. She connected a sensor and her laptop to rods attached to the tree to measure its water content. Sometimes electricity conducted by the tree shorted out her sensor, or bands measuring tree girth fell down when the trees shed water. The process is now automated and the devices she uses are more reliable.
Young-Robertson will continue to monitor plots in the research area, but will also establish and follow another plot this fall near Smith Lake. It will include birch, aspen and spruce, collecting data on air temperature, soil temperature, water content and tree girth.
One reason for placing the plot near UAF is that she hopes to stream the data to a website so people can track ongoing conditions and watch for the best time to harvest.
Young-Robertson, a researcher for the Agricultural and Forestry Experiment Station, will expand the project with additional grant money expected this fall. She hopes to increase the number of plots at the research watershed and to add a plot on Fort Wainwright so she can monitor trees in various conditions.
|Jessie Young-Robertson demonstrates how a device measures|
water content. UAF photo by J.R. Ancheta
Young-Robertson has many interests besides ecohydrology. She is an artist who paints with vivid acrylic colors and creates art with a digital drawing pad. She is interested in the connections between science and storytelling. She recorded a series of conversations with scientists and others as part of a collaboration with StoryCorps, which airs stories on National Public Radio. She also told a story about a disastrous solo hike on Kesugi Ridge as part of the Dark Winter Nights storytelling series. She hails originally from New Mexico, where her father worked as a research physicist.
She likes her work with trees and their mysteries. She discovered they conduct electricity and they even pick up radio stations. Trees conduct sound when they’re full of water, she said. She could pick it up with specialized sensors that measure changes in pressure that she converted to sound.
“I feel like at every turn, we find something new,” she said.