From Hugo to Matthew: Clemson Studies Coastal Forests that Come Full Circle

Aug 31, 2017

The Hobcaw Barony in Georgetown, South Carolina is a rare place. Situated between the Winyah Bay estuary and the Atlantic Ocean, the property contains both freshwater habitats and salt marshes, interspersed with loblolly and longleaf pine forests. The variable ecosystems that Hobcaw supports make it the ideal site for university research centers such as Clemson University’s Belle W. Baruch Institute of Coastal Ecology and Forest Science.

A Baruch Institute research team led by Dr. Tom O’Halloran has spent the past nine months tracking the growth of trees in Hobcaw’s forests. The storm surge from Hurricane Matthew flooded inundated the woods with sea water in October 2016, prompting questions about the impact the salt water might have on the forest, which was previously flooded by Hurricane Hugo in 1989.

“There was a lot of luck involved in all of this,” O’Halloran said, as he hiked through one of his team’s research plots.

Hurricane Matthew was certainly an omen of very bad luck in most every context, but for the sake of this team’s research, it was indeed a stroke of luck that Matthew’s storm surge flooded Hobcaw in such a similar fashion as Hugo's did several decades earlier. For the Baruch Institute faculty, it provided a golden opportunity to study how repeat storm flooding conditions might affect other forests as well.

Back in 1989, salt water from Hugo’s storm surge settled in the soil, causing many of the older trees in this forest to die. According to research technician Maggie Wilkinson, early research so far appears to indicate similar results from Matthew’s storm surge.

“We can see a really big trend so far with the salinity—where it was so high back in October, and now it’s kind of leveling back out. Also, you can see where the salinity was high where the pine trees are dying off,” Wilkinson said.

Dr. Tom O'Halloran points out a young tree that has grown since Hurricane Hugo destroyed much of this forest in 1989.
Credit Olivia Aldridge/SC Public Radio

Back on one of the team’s research plots, O’Halloran pointed out that smaller, thinner trees now grow between old, towering pines.

“This tree has grown post-Hugo, since the hurricane,” he said, pointing to a small tree. The larger trees are Hugo survivors.

Clemson University senior Mike Aylett, an intern at the Baruch Institute, demonstrated how they measure the young trees, wrapping a measuring tape around a trunk at breast height. The trees Aylett is tasked with measuring are tagged with orange markers, each with a unique, identifying number so that their growth can easily be tracked at three-year intervals.

Even before the young trees Aylett measures were seedlings, one Baruch Institute faculty member was already studying this very plot. Clemson University Professor Emeritus Dr. Tom Williams had been on Clemson’s faculty for 14 years when Hugo hit South Carolina’s coast.

“Hurricane Hugo was an event that a lot of people hadn’t seen; there hadn’t been anything like that since the fifties, so it was an opportunity to see what happens after a hurricane,” Williams said. “Within a year or so, we began to see areas of forest that the nettles started to turn red, and the trees all died.”

According to Williams, his research team had access to what was, at the time, brand new technology, including GIS mapping programs and aerial photography equipment, which allowed them to map the effects of Hugo on a broad scale. His team also tracked the perimeter of the storm surge by studying debris deposited by the surge, like pine cones.

That’s where the biggest stroke of luck occurred.

After Hurricane Matthew, Williams marked the perimeter of the storm surge just as he had done with Hugo. Although Matthew brought about 6 feet of water into the forest as opposed to Hugo’s 10 feet, the perimeter lined up almost exactly with the storm surge of Hugo, within about four inches.

“As somebody said, ‘we always have the good fortune to have an unfortunate hurricane come by,’” Williams joked.

The circumstances of this research are especially unique, Williams observed, because funding for long-term projects like this one is difficult to come by. In fact, even many individuals in the forestry community criticized the research coming out of the Hobcaw plots as redundant and unnecessary prior to Matthew.

Dr. Tom Williams, professor emeritus at Clemson University, has studied Hobcaw's forest plots for decades.
Credit Olivia Aldridge/SC Public Radio

“From 1993 until 2016, several people had criticized the data that was coming out of those plots as, ‘Well we knew that!’ But we don’t know what happens when another hurricane hits. All of a sudden we have data that’s irreplaceable,” Williams said.

The team’s work will continue at least until October of this year, giving them a year’s worth of research to process before reporting their findings to the National Science Foundation, which has funded their research since Matthew.

In the meantime, the team recently enjoyed a different type of luck: the opportunity to watch the Great American Solar Eclipse in its totality from their very own Hobcaw backyard.