Along the eastern coast of the United States, forests that once formed dense green canopies are now marked by clusters of bare gray trunks. These are the remains of trees killed by rising saltwater, also known as ghost forests.
Now, recent research also indicates that these changes affect the surrounding ecosystem in ways that extend beyond their haunting appearance.
Researchers from the University of Delaware presented findings at the American Chemical Society Spring 2026 meeting in Atlanta showing that as coastal trees die, the movement of water and nutrients through the forest changes. These changes could alter how these ecosystems store carbon, with effects that reach beyond the immediate forest area.
When the Water Stops
The research focuses on a process called stemflow, which is the rainwater that moves down branches and along tree trunks to the forest floor. Stemflow serves as a concentrated delivery system, transporting nutrients, dissolved carbon, and other important chemicals directly to the soil near tree roots. Microbial communities in the soil also rely on these inputs.
“Stemflow is basically injecting nutrients and really important chemicals into the forest ecosystem so the microbiome there can thrive,” said Yu-Ping Chin, one of the study’s supervisors and a researcher at the University of Delaware.
Undergraduate student Samantha Chittakone and her colleagues collected stemflow from healthy, stressed, and dead sweetgum trees along the mid-Atlantic coastline to study how ghost forests affect this process. Sweetgum grows widely across the region and often occupies areas affected by saltwater intrusion. The results showed clear differences between the condition of the trees.
Dead trees appeared to absorb the water rather than channel it to the ground. As a result, much less stemflow reached the forest floor, reducing nutrient supply to the soil ecosystem.
“The stemflow’s being absorbed by the dead trees. They’re acting like sponges,” Chin said. “Suddenly you cut off water, nutrients and dissolved organic carbon to the forest floor. Not only is this changing the health of the trees, but it changes the health of the forest floor.”
An Unexpected Sugar Spike
The team also analyzed the chemistry of stemflow from dying and stressed trees and found higher sugar concentrations than expected. This result suggests additional ecosystem changes that warrant further study.
Delphis Levia, another project supervisor, suggested that this increase in sugar transport could alter the soil microbial communities near the bases of dying trees. The effects of these changes on carbon storage, soil chemistry, and the organisms that depend on them are still being investigated.
“Our results signify that the transition from healthy trees to ghost forests changes the magnitude and chemistry of stemflow, leading to pronounced differences in dissolved carbon inputs,” Levia said. “Further research will better contextualize these changes in stemflow chemistry on the overall cycling of carbon in coastal forests.”
The study also examined how stemflow interacts with groundwater, which is often close to the surface in coastal forests. The team used dissolved lignin as a tracer for tree-derived organic matter and found that stemflow from healthy trees contributed to groundwater chemistry. As trees die, reduced stemflow lowers this contribution.
A Warning Written in Wood
Chittakone noted that the research has broader significance beyond the data collected.
“Walking through these coastal forests, surrounded by nature, is beautiful,” she said. “However, it is disheartening to see the healthy trees becoming less prevalent as you approach the shoreline and the effects of rising sea levels become apparent.”
Ghost forests serve as a diagnostic tool for scientists. The visible and relatively rapid transition from living forest to skeletal remains allows researchers to observe ecosystem disruption as it occurs and to document the associated changes.
“Stemflow is a significant transporter of nutrients and other important chemicals in these coastal forests,” Chittakone said. “It’s something that we should study more and not overlook whenever it comes to carbon cycling, especially in these vulnerable ecosystems.”
The research was funded by the U.S. National Science Foundation and is part of a broader investigation into how stemflow functions across different disturbance scenarios, including wildfires.
The Bigger Picture
Ghost forests are already widespread along the Atlantic coast. As sea levels rise, saltwater intrusion will continue to move further inland. As a result, the zone where living forests give way to standing dead trees will continue to grow, further disrupting the carbon and nutrient cycles that sustain coastal ecosystems.
Studying how stemflow changes as trees die is important for understanding which coastal forests are most vulnerable, how quickly they may decline, and what these changes mean for carbon storage in these ecosystems. Researchers are just beginning to document changes in ghost forests and understand their broader ecological impacts.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.