By MarylandReporter.com/Capital News Service, a student-powered news organization run by the University of Maryland Philip Merrill College of Journalism
Stephanie Stotts, a University of Maryland Eastern Shore scientist, checks the tag on a dead loblolly pine tree that was alive when she tagged it within the past four years. Bay Journal photo by Dave Harp.
As Coastal Woodlands Die to Saltwater and Turn into Ghost Forests, Scientists Study the Causes and the Pace
It’s safe to say that Tree No. 160 won’t be standing for much longer.
When a scientist tagged the loblolly pine at some point within the last four years, it was alive. The silver medallion bearing its identification number remains tacked into the tree’s side about 6 feet up from the ground. But the evergreen has now turned forever brown.
The pine’s needles and most of its branches are gone. Its trunk is riddled with insect holes. Chunks of bark are missing. And it has plenty of company.
Dead and dying trees, impacted by rising levels of saltwater, form a “ghost forest” near Monie Bay in Somerset County. Bay Journal photo by Dave Harp
“You can see that there are all of these dead trunks,” said Stephanie Stotts, a forest ecologist with the University of Maryland Eastern Shore, as she surveyed the eerie scene. “You can see clearly that something is happening here. It was a forest. And now it’s no longer a forest.”
Such “ghost forests” are among the most tangible indications of a changing climate in the Chesapeake Bay region. In just a four-county swath of Maryland’s Eastern Shore, state surveys show that more than 400,000 forested acres have been newly impacted by saltwater over the past decade. Those trees, scientists say, are doomed, soon to be replaced by marsh.
But scientists have only recently begun to unlock the mysteries lurking within these haunting places. Like: Why do some trees cling to life much longer than their neighbors? Do tree rings hold any clues? Can we predict where trees are going to die next?
A five-year, $2 million research effort funded by a National Science Foundation grant has shed unprecedented light on the phenomenon, igniting a spate of studies across the Bay area. Scientists have been so intrigued by their findings that they’re looking for ways to extend their investigations beyond next year when the funding is expected to dry up.
University of Maryland Eastern Shore scientist Stephanie Stotts slogs through a muddy wetland to get to her research plot at Monie Bay on Maryland’s Eastern Shore. Bay Journal photo by Dave Harp
Such research is critical to understanding how climate change will impact coastal ecosystems and communities, said Greg Noe, a U.S. Geological Survey wetland scientist based in Delaware who is not involved in the NSF studies.
“We’re starting to see some rapid, dramatic changes now,” he said. “It’s a warning. If we don’t like the change we’re seeing now, there will be more of it in the future, and we need to be prepared.”
The climate project is led by University of Delaware hydrogeologist Holly Michael and involves several other institutions across the Bay region. The effort seeks to unpack what happens to crops, forests, groundwater, carbon storage and other coastal matters as the sea level rises — and what can be done to protect them.
Rising seas are carrying lethal doses of salt farther inland during hurricanes and unusually high tides. In that way, scientists say, dying forests are a leading indicator of sea level rise.
What secrets have ghost forests been hiding?
Stephanie Stotts, a University of Maryland Eastern Shore researcher, walks through a stand of phragmites that was once a woodland adjacent to Monie Bay on Maryland’s Eastern Shore. Bay Journal photo by Dave Harp
Stotts must slog deep into a tick-infested woodland, trudge waist-deep through multiple muddy sloughs (smelling very much like rotten eggs) and pick her way through a thick stand of phragmites to arrive at her research site. Other ghost forests are more accessible. But this Monie Bay marsh, near the mouth of the Wicomico River in Somerset County is part of the Chesapeake Bay National Estuarine Research Reserve and likely to remain in its natural state in perpetuity.
She halted at the spot along the rough-hewn trail where living trees begin to give way to marsh grasses and dead snags. She faced inland, where young trees still populated the landscape. To her rear, there were no young to be seen.
“So, there’s this very visible line where essentially regeneration stops,” she said.
She studies tree rings to determine what happened in the past. Most of the trees here are about 100 years old, she has found. She suspects that the impacts of saltwater intrusion first appeared in the 1970s and ’80s, because virtually no trees sprouted in the “transition zone” during that period. Only after Superstorm Sandy struck in 2012, dumping a crush of freshwater onto the landscape, did young trees spring up again in large numbers.
A tree that was alive when tagged by researchers within the last four years now lies rotting as saltwater intrusion converts forest to marsh in Somerset County. Bay Journal photo by Dave Harp
Up to a point, trees are naturally resilient to sea level rise, Stotts said. As they drop needles and leaves over the years, they slowly build up the land elevation immediately around them. Even if the lower ground gets flooded by saltwater, these small hummocks can collect just enough freshwater from rainfall to extend the tree’s survival by years or decades.
The research is uncovering a complex interplay at work within ghost forests, Stotts explained. For example, when trees die, their roots shrink and the ground sinks accordingly, making the spot once inhabited by a living tree now more vulnerable to flooding.
On the other hand, as trees grow more stressed from saltwater intrusion and increased flooding, they don’t absorb as much water from the surrounding terrain. That means more freshwater is available to lower the salt concentration of brackish floodwaters, Stotts said.
“It’s a lot more complicated than any of us realized,” she added.
It’s also happening more quickly than anyone realized, she and other scientists agree. But even that basic information — the measurable pace of change — is valuable in helping them predict the future of coastal forests.
