A tree’s annual progress rings reveal the way it has flourished—or floundered—over time, with the scale of the rings indicating years of well being or hardship. But generally nature throws a wrench into the works, and a tree will kind a couple of progress ring in a 12 months. Now, such “false rings,” present in bushes alongside the U.S. Gulf Coast, have been linked to hurricanes, researchers report right this moment at a gathering of the American Geophysical Union. With tree ring data stretching again greater than 1000 years, the crew is making ready to look at how the frequency of historic storms compares with our fashionable, warming world.
Clay Tucker, a geographer on the University of Alabama, Tuscaloosa, and his colleagues spent a lot of 2020 and this 12 months wading and canoeing by means of stands of bald cypress bushes throughout three river basins in coastal Mississippi, Alabama, and Florida. The crew extracted pencil-width cores of wooden from roughly 120 bushes—a method to exhume a tree ring file with out hurting the bushes, Tucker says. “A woodpecker would do more damage.”
Back within the laboratory, the researchers examined the cores underneath a microscope to search for false rings, which kind when a tree that’s stopped rising for the season is all of a sudden kick-started out of dormancy. One frequent set off for a secondary progress spurt is flooding, Tucker says. “The tree doesn’t know it’s not spring.”
Next, Tucker and his colleagues linked 20 cases of false rings since 1932 with large floods, as recorded by stream gauges. Roughly 80% of these “flood years” had additionally skilled an accompanying tropical storm or hurricane, the crew reviews. That is smart, Tucker says, as a result of streamflow is strongly linked to storm-related rainfall. “Water resources … in the southeastern United States depend on hurricanes.”
Dave Stahle, a geoscientist on the University of Arkansas, Fayetteville, who was not concerned within the discover, says the sturdy affiliation between false rings and storms will assist scientists clear up a basic query: Has the frequency of hurricanes making landfall gone up or down over time? Some analysis suggests we’d see extra hurricanes because the local weather warms. But firming up that speculation would require a hurricane file that goes additional again in time, Stahle says.
The new bald cypress file ought to supply precisely that, Tucker says. The crew is about to begin analyzing its core samples, a few of which include wooden greater than 1000 years previous. The researchers are additionally wanting ahead to combining their measurements with one other proxy file of hurricanes: storm-tossed sediments. Tree rings have the benefit of being annual, however sediment data stretch additional into the previous, Tucker says. “Maybe we can marry the two.”