Rising starkly from the marshy lowlands, the pale remains of trees stand like skeletal guardians against the horizon. These are ghost forests, an unsettling testament to changing climate and rising seas: dead trees, bleached white by the sun, stripped bare by saltwater.

They are particularly prevalent in the mid-Atlantic region. “This area experiences some of the fastest relative sea level rise rates in the world, combined with a gently sloping, low-lying coastal plain,” says Matt Kirwan, a coastal ecologist and researcher at the Virginia Institute of Marine Science. “Even a small rise in sea level can lead to significant forest death, making ghost forests especially abundant here.”

Ghost forests are not unique to the US. Similar phenomena are observed in coastal areas worldwide, from Europe to Australia. They form through a combination of natural and human-induced factors, including sea level rise, saltwater intrusion, flooding, and storm surges — all of which are influenced by a warming climate. These factors cause the salinity of the soil to increase, stressing trees that are unable to adapt, killing them and leaving them to haunt the coasts. But just as apparitions signify a need to let go of the past, ghost forests can sometimes herald a better future, new research suggests.

“You can’t save the trees, but you can ensure a healthy marsh replaces them,” says Kirwan, whose research focuses on the ecological benefits of thriving marshlands. “Marshes are great for bird habitat. They’re great for animal habitat. They’re good for improving water quality, for protecting shorelines from waves and flooding. Their marshes are important for sequestering carbon in their soils. And, you know, basically just about every commercially important fish has some dependence on the marsh.”

Ghost forests impact the environment in a variety of ways. Soil degradation and erosion lead to death and decomposition of trees, and this can destabilize the soil, leading to nutrient loss and reduced habitat quality for new vegetation. Water quality deterioration is another problem, because the decomposition of organic matter can lead to eutrophication — a process where nutrient overloading causes algal blooms. These blooms deplete oxygen levels in the water, creating “dead zones” that are uninhabitable for aquatic life. The presence of ghost forests also increases the flood risk of surrounding areas, as the loss of tree cover reduces the landscape’s ability to absorb floodwater.

Coastal communities that depend on forests for tourism and fisheries are facing significant economic challenges as these ecosystems change. The transformation of ghost forests affects not only local livelihoods but also property ownership, as lands flood without the protective barrier of forests. In the mid-Atlantic region, this displacement is becoming more common. Additionally, the formation of ghost forests has a profound impact on agricultural communities, as saltwater intrusion renders the soil unsuitable for crops, degrading valuable cropland.

“Ghost forests often signify a transition from forest to marsh, which is not necessarily a bad thing,” says Marcelo Ardón, an associate professor at North Carolina State University who studies the ecological impacts of wetland transitions, including how ghost forests can evolve into carbon-sequestering marshes. “While losing an entire ecosystem to open water is a worst-case scenario, transforming a ghost forest into a marsh can be beneficial. Marshes, for instance, sequester carbon more efficiently than forests in some cases, which is crucial for reducing atmospheric carbon levels.”

Salt marshes often outperform forests in CO2 sequestration. They can be vibrant ecosystems and home to fast-growing plants like grasses and sedges, which rapidly capture CO2 through photosynthesis. When these plants die, their remains fall into the waterlogged soil, where low oxygen levels slow decomposition. This unique process buries significant amounts of carbon in the marsh, slowing its return to the atmosphere.

Marshes provide critical habitat for a variety of species, as well, particularly birds, fish, and invertebrates. As marshlands expand, they create new opportunities for wildlife that depend on wetland ecosystems. This increase in habitat diversity can lead to healthier and more resilient coastal ecosystems, despite the initial loss of forested areas.

Despite these benefits, the transformation process is complex and requires careful management. Initiatives such as community-led marsh restoration projects and policy measures aimed at reducing carbon emissions are crucial in addressing the root causes and consequences of these changing landscapes. Successful case studies, like those in the Chesapeake Bay area, demonstrate the potential of collaborative efforts.

One complex ecological challenge that researchers face when converting ghost forests into marshland involves the invasion of phragmites australis, an aggressive non-native reed. This fast-spreading plant quickly takes over newly formed marshlands, outcompeting native species and reducing biodiversity. The dense stands of phragmites not only crowd out native vegetation but also disrupt habitats that are crucial for local wildlife, disrupting the natural balance of these ecosystems.

“Phragmites have found ghost forest areas a prime location for rapid colonization and growth,” says Serina Wittyngham, assistant professor at the University of North Florida. Wittyngham has been collaborating with the US Fish and Wildlife Service to explore effective management strategies, beyond the prescribed burns and herbicide applications that the agency currently uses, aiming to preserve biodiversity in these transitioning ecosystems. “Unlike the slower natural marsh migration, phragmites invade these spaces at an alarming rate, moving into forests at about five meters per year. This rapid spread poses a significant threat to the biodiversity and balance of these ecosystems.”

Wittyngham has spent the past two years tackling the invasive spread of phragmites in ghost forests, seeking the most effective management strategies. Her findings indicate that prescribed fire alone can significantly increase native species diversity, with several unique species thriving in fire-only treatment plots. Additionally, herbicide applications have proven highly effective, eradicating up to 95 percent of phragmites.

Ghost forests provide a stark reminder of the consequences of climate change. Yet, they also offer lessons in resilience and transformation. Through research, conservation strategies, and collaborative efforts, these ghostly woods can become vibrant, carbon-capturing marshlands.

“Expanding marshlands can create valuable habitats for marsh birds and other wildlife,” Ardón says. “From a biodiversity perspective, the growth of marshes at the expense of forests isn’t always negative; it can be a sign of adaptation and new ecological opportunities.”