Highlights
- Tree rings from coastal oak forests in New York and Rhode Island recorded the impacts of major hurricanes in the Northeast.
- Analyzing wood anatomy alongside ring width helped researchers identify storm signals more clearly than ring width alone.
- The study suggests tree rings could help extend the Northeast’s hurricane history beyond the written record.
- The findings also suggest that rising sea levels may be placing growing stress on vulnerable coastal forests.
Researchers from Columbia University and William Paterson University have found that coastal forests in the Northeastern U.S. contain a record of major hurricanes and show that trees are recovering from storms within two years. The findings also suggest that coastal trees may already be showing signs of stress from sea-level rise.
The researchers published the results in the journal Global and Planetary Change.
The study focused on three coastal forests in the Northeast: two in New York (Montauk and Shelter Island) and one in Newport, Rhode Island. The research team collected cores from oak trees at all three sites and analyzed them in two ways. First, they measured ring width—the traditional tool of dendrochronology—which shows how much a tree grows each year. They also examined the microscopic structure of the wood, including the size and arrangement of vessels that move water through the tree, to better understand how the trees function during periods of stress. These two approaches allowed the team to test whether storms and rising seas had left detectable marks in the trees’ growth patterns.
“We went into this asking a pretty basic question: would the storms even show up in the tree rings? And they did,” said lead author Nicole Davi, a professor at William Paterson University and an adjunct senior research scientist at the Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School. “That was exciting on its own, but what really stood out was the trees’ resilience and how quickly their growth bounced back from storms.”
The records from those cores stretch back as far as the 18th century, potentially giving the researchers a much longer view of storm impacts than modern observations alone.
The researchers found that while tree growth dropped significantly the year following major hurricanes, the forests generally recovered in about two years. “This information could inform foresters or other decision-makers when it comes to forest conservation and restoration initiatives,” said Davi.
But storm recovery may be only part of the story. In Montauk, the trees grew less in years when coastal water levels were higher than their long-term average. Even as sea level rises steadily over the long term, coastal water levels can run unusually high in some years because of shifting ocean conditions, weather patterns and tides. The team suspects that higher water tables or salt exposure may be wearing these forests down, but this is a topic Davi and her colleagues hope to investigate further as the research continues.
“Sites like Montauk are rare and important because they preserve a long history of environmental change in one place,” said coauthor Mukund Rao, a research professor at Lamont. “The fact that these trees record major hurricanes and possibly the effects of higher coastal water levels makes them valuable for understanding how coastal ecosystems respond to environmental pressures.”
Davi and colleagues ultimately hope to use tree rings to reconstruct a hurricane history for the Northeast that extends back before the 1850s, when written records began. The team recently received funding to expand their work to more sites and more tree species. They will also install tools called dendrometers, which track subtle changes in tree growth over time. This next phase of work will help researchers get a clearer sense for how coastal forests respond to flooding, salt exposure and other stresses as conditions along the coast continue to change.
The research team included Lamont’s Ed Cook, Caroline Leland and Laia Andreu-Hayles (also of the Centre for Ecological Research and Forestry Applications in Spain), Arturo Pacheco-Solana of the University of Padua and Neil Pederson of Harvard Forest.
The research was sponsored by the New Jersey Sea Grant Consortium with funds from NOAA’s Office of Sea Grant, U.S. Department of Commerce.
