"Ghost forests" along U.S. coasts are a haunting indicator of climate change
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Forests inundated with salt due to rising sea levels are turning into cemeteries of trees — a haunting indicator of climate change. It's a problem on coastlines across the United States, most dramatically between North Carolina and Massachusetts, where the sea level is rising three times faster than global rates.
The Chesapeake Bay is especially vulnerable to "ghost forests" because land in the region is flat. In Maryland, the forest has been retreating at a rate of 15 feet a year — and that rate is accelerating.
"The ghost forests are the most striking indicator of climate change we have anywhere on the East Coast," said Matthew Kirwan, a coastal ecologist at the Virginia Institute of Marine Science who has been studying ghost forests and their impact on coastal ecosystems for years.
"We're used to seeing pictures of glaciers that have melted and retreated back miles, over the last several decades. Well, it's the same thing here," he said. "We have the remains of trees ... that mark where dry land was just decades ago."
Ghost forests result from sea level rise and coastal flooding that bring in salt, which accumulates in the soil. Eventually, the salt builds up to levels the trees can't withstand. They die, surrounded by marsh, with no new trees to replace them, Kirwan said.
The process can be slow, he said. At first, one may only notice a few dead trees each year, but over time, a whole group of trees will disappear.
Since the late 19th century, at least 100,000 acres of forest along Maryland's Chesapeake Bay have turned into a growing collection of tree graveyards. Researchers predict that over the next century, up to 18,000 square miles of dry land in the U.S. — about the size of Maryland and Vermont combined — could be submerged in water.
Kirwan's family has lived along Maryland's Eastern Shore for 10 generations. For him, watching the trees die is not just a scientific concern, but a personal loss as communities disappear.
"Everybody thinks of sea level rise in terms of flooded city streets and subways and catastrophic hurricanes like Katrina," he said. "But really, the impacts of sea level rise in most places are far more subtle."
Kirwan said he has struggled to come up with a solution for saving hundreds of thousands of acres of forest.
"And so, where I come down is to try to ensure that if we're going to lose all that forest, that we at least get something in return," he said. "And that's the marshes."
Kirwan and a team of researchers are working to nurture the marshes, which he said provide many benefits.
"They rival the tropical rainforests. They sequester carbon, they improve water quality," he said. "And so, the loss of the trees is inevitable. But whether we get marshes to take their place and what kind of marsh it is, that's not inevitable."
Farther north, in New Jersey, a similar mission is underway to address the rapid rise of ghost forests. Forester Bill Zipse is overseeing a tree restoration site built by the state 10 years ago. The objective is to reforest 10,000 acres of Atlantic white cedar trees that were destroyed by Superstorm Sandy and saltwater intrusion. Zipse's team is planting new trees miles inland, where they are less likely to become ghost forests.
He said adaption amid climate change is key, and that while the forest may never again be what it was before, the resource can still be kept alive on the same landscape.
The effects of the restoration project extend far beyond the forest.
"It plays a role in a much larger role in the overall surrounding ecosystems," Zipse said. "I think that's important for people to remember. It's not a hopeless story. These forests can be restored. They can be saved, and you can adapt."
