Between the Lines: Tree Rings Hold Clues About a River's Past
Phys.org Wednesday, Jan. 10, 2018
Hydrologists are looking centuries into the past to better understand an increasingly uncertain water future. By analyzing centuries-old growth rings from trees in the Intermountain West, researchers at Utah State University are extracting data about monthly streamflow trends from periods long before the early 1900s when recorded observations began. Their findings were published Jan. 6 in the Journal of Hydrology and, for the first time, show that monthly streamflow data can be reconstructed from annual tree-ring chronologies—some of which date back to the 1400s. "By linking tree rings and flow during the past 100 years when we have recorded observations, we can use trees as a tool for measuring flow long before there were gauges on the rivers," said USU's Dr. James Stagge, a hydrologist and civil engineer who led the research. ... "One data point per year gives a very limited picture," said co-author Dr. David Rosenberg, an associate professor of civil and environmental engineering at USU. ... The model overlaps the tree-ring chronologies and combines annual streamflow information and climate data to arrive at a monthly streamflow estimate.