Tucked into the humid wetlands of the American Southeast, the bald cypress rises with quiet determination. These towering trees, known for their knobby knees and flared bases, don’t just dominate the swamps – they define them.
Many bald cypress trees have been standing for thousands of years, enduring floods, poor soil, and relentless humidity. But their survival story is not without challenges, as bald cypress trees are now facing a barrage of threats.
While animals age and die, trees tend to live until their environment wears them down. The story of the bald cypress is one of endurance – but also one of vulnerability.
Buried cypress trees tell an old story
Scientists from Florida Atlantic University, in collaboration with Lynn University, the University of Georgia, the Georgia Department of Natural Resources, and the Georgia Museum of Natural History, recently uncovered an ancient timeline buried at the mouth of Georgia’s Altamaha River.
There, the team found subfossil bald cypress trees – remnants of a once-thriving forest that time had preserved in mud and sediment.
To understand how these trees responded to past climate changes, researchers used radiocarbon dating and analyzed the tree rings – measuring their size and number.
Each ring captured a snapshot of that tree’s life in a given year, offering a long, unbroken record of environmental conditions. What the trees revealed was startling.
Sudden shift around 500 A.D.
Before 500 A.D., bald cypress trees at this site routinely lived over 470 years. But after that time, their lifespans fell dramatically – to just 186 years on average.
At the same time, the trees started growing faster. That may sound like a good thing, but quick growth often means less structural strength and increased stress.
This timing aligns with a dramatic climate event known as the Vandal Minimum – a global cooling period caused by volcanic eruptions and possibly a comet impact.
These upheavals altered the atmosphere and, in turn, the ecosystems below. As the planet cooled, the once-resilient bald cypress began living shorter, more fragile lives.
“The last of the long-lived trees found in the deposit died during another major climatic event, the Little Ice Age,” said Katharine G. Napora, Ph.D., the study’s senior author.
“Our findings underscore how long-lasting the localized effects of major climate shifts can be, especially for coastal forests that are already vulnerable to wind damage, saltwater intrusion and rising seas.”
Climate impacts on cypress trees
Despite the abrupt change in tree lifespans, researchers found no signs of fire, human activity, or logging at the site. There’s no clear smoking gun – no single event or threat that explains the decline.
What’s clear, however, is that the cypress trees never bounced back. Even centuries later, they failed to reach their former lifespans.
“This shift wasn’t a brief disruption. Even centuries later, the trees never regained their former longevity. In fact, their lifespans continued to decline over time,” Napora explained.
Scientists believe several factors could be responsible. Coastal conditions may have become more unstable – with more frequent storms, salinity spikes, and inconsistent flooding patterns.
During dry periods, pests like mites likely thrived and added more stress. Together, these shifts may have created an environment where longevity was no longer possible.
Cypress trees as climate timekeepers
The researchers studied 95 subfossil bald cypress trees from the Altamaha Wildlife Management Area. These trees had been buried for centuries and were unearthed during regular land maintenance work.
The well-preserved condition of the trees gave scientists an ideal record for examining past growth without interference from modern preservation differences.
“These ancient giants not only inspire awe but also serve as natural archives, helping scientists understand how trees have weathered past climate events – and how they might fare in the face of modern climate change,” Napora said.
And these are not the only cypress trees with climate stories to tell. In parts of the Southeast, living bald cypress trees between 800 and 2,600 years old still stand today. They’ve survived massive environmental shifts and now live as rare survivors in old-growth swamp forests.
The story of the Earth, written in wood
While the Vandal Minimum was not a global freeze in the way we often imagine, it was felt in many corners of the world. The bald cypress offers a unique look into how such broad changes ripple through ecosystems – and linger for centuries.
“The rings of the bald cypress are like nature’s journal entries, written year by year and season by season, showing how even slow changes can shape the course of life,” said Napora.
“In their quiet persistence, these trees offer both a warning and a lesson: that the world is more interconnected than we often realize, and that the story of the Earth isn’t only told through written history – it’s etched into wood, embedded in landscapes and carried forward by living organisms.”
“The past lives on in the trunks of these ancient trees, reminding us that environmental shifts – whether natural or human-caused – reverberate through time in ways we are only beginning to understand.”
In a time of rising uncertainty, these trees are more than survivors. They are storytellers, and we’re just learning how to listen.
The full study was published in the journal Proceedings of the National Academy of Sciences.
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English (US) ·