Whether by fate, happenstance, or choice, those of us who are fortunate enough to reside in these magnificent Outer Banks realize Mother Nature here is a keenly unique environment, head-strong and stubborn. We are a thin strip of sand with a vast, salty ocean on one side and fresher water on the other side. The annual constant negative nature provides here is storms: hurricanes and nor’easters, all with wind and torrents of water, devastating us, vegetation, and the shallow sand band on which we live.

Regardless of the ultimate cause of our weather patterns recently changing toward more storms, more and more saltwater encroaches on the land as the sea level rises. The Outer Banks now exhibits evidence similar to many areas along the world’s coasts and estuaries, invading seawater advances and overtakes the freshwater that deciduous trees rely upon for sustenance. The salty water slowly poisons living trees, leaving dead and dying timber haunted ghost forest. 

Eastern Carolina University Department of Coastal Studies assistant scientist Dr. David Lagomasino recently visited the Florida Keys and Everglades National Park to examine the extent of mangrove mortality after Hurricane Irma. Projects similar to these are in planning for the Outer Banks.

The water is gaining as much as 5 millimeters per year in some places, well above the global average of 3.1 millimeters, driven by profound environmental shifts that include climate change.

Increasingly powerful storms, a consequence of a warming world, push seawater inland. In addition, more intense dry spells reduce freshwater flowing outward. People living on Chesapeake Bay’s eastern shore, the country’s most extensive estuary system, have a front-row view of the sea’s rapid advance. That says wetland ecologists at George Washington University. Because of the extraordinary speed at which the water is rising here, the speculation is that this area shows a window into the future for the rest of the world.

If not, impenetrable stands of cane-like Phragmites, an invasive species, take over.

The effects of rising seas are so noticeable here on the Outer Banks and most eastern coasts because the land has a minimal slope. So those five millimeters of sea level, a rise that’s only slightly more than two half-dollar coins stacked, can translate into saltwater pushing 15 feet inland per year.

Shoots of sweet gum, a tree with star-shaped leaves and bark-like alligator skin, have more tolerance for salt than other hardwoods, such as oak. As a result, they can endure as groundwater becomes more saline. But eventually, the sweet gum dies as well.

This trend initially depressed the biologists with the Fish and Wildlife Service who work at the refuge. Saltwater marshes are important nurseries for the fish and crabs people like to eat. But
 in 2012, they realized the marsh wasn’t entirely disappearing; it was migrating. In addition, some of the 3,000 acres of forest that the refuge had lost had transformed into a saltwater marsh. These signs of change come from the ocean, a fluid, and often fickle environment. 

The trees themselves have long been prized for lumber. Its wood is highly resistant to rot. But the tree is also susceptible to salt. It can tolerate maybe three salty high tides before succumbing.

So when the trees begin dying, it’s a trustworthy indicator that conditions are becoming more saline. It is an age-old phenomenon, now happening faster.

Erosion of marshes and riverbanks has also accelerated, revealing buried cedar stumps from prehistoric ghost forests. So this is not a process purely isolated to occurrence in the 21st Century.

How quickly do ghost forests form?
A study was done similar to one done 15 years previously, and, as expected, the saltwater marsh had advanced. As a result, pond pine and other salt-sensitive trees were dying. But, on the other hand, salt-tolerant plants, including sawgrass and black needle rush, were moving in.

But unexpectedly, the change wasn’t occurring evenly across the landscape. Instead, trees were dying faster in some places than others.

What could explain this uneven emergence of ghost forests?

The study area had almost no slope — much of it was just inches above sea level — and the minor differences in elevation couldn’t explain the variation.

But a clue came from the soil. It tended to be saltier where trees were dying fastest. It had to do with drought. When droughts hit, the amount of fresh water emptying into the ocean from nearby rivers declines, making near-shore waters saltier in some places.

That saltier water then pushes inland unevenly, killing trees irregularly across an otherwise mostly uniform landscape. The conductors of these studies concluded it was not just rising sea level that creates ghost forests, but periods of dryness. And that it was more during times of drought, with less freshwater, that the salt water creeps in and salinity goes up.”

Wildfires are another accelerant.

Wetlands burn naturally here during dry years. Fires often travel on top of standing water, consuming grass and trees above the muck.

In the past, young trees quickly sprouted after fires. But recently, some forests have failed to recover.

“There’s almost no regeneration,” explains Chris Moorman, a disturbance ecologist at North Carolina State University. The conclusion is that wetlands like these have become too salty for young pond pines, which are more sensitive to salt than mature ones. As a result, they can’t gain a foothold in marshes their forebears could tolerate.

Dr. Taillie said that drought is predicted to become more frequent as the climate warms. That means wildfires, combined with intensified dry spells and amplified saltwater intrusion, may, together, accelerate the formation of ghost forests independently of sea-level rise.

The synergy of fire and salt produces particularly dramatic ghost forests. Along the Chesapeake Bay, stands of trees might gradually thin near open water until just a few scraggly pines remain. But in some places in our area, acre upon acre of dead trees, sun-bleached and occasionally fire-blackened, stand sentinel over bubbling marshes.

Yet while the ghost forests may evoke graveyards, the salt marsh plants that advance into dead and dying stands of trees are valuable. Marshes provide homes for birds; they serve as nurseries for young fish and other sea creatures. And as the sea advances, the new wetlands also provide a momentary buffer against the rising tide — protecting the forests whose time has not yet come and giving us a barrier to keep the winds at bay through another storm.