Inside the mystery forests of the marshlands

When I first saw them, rising from the horizon, the trees in the distance looked like a lime-green stadium. The towering formation represented the telltale signpost for an isolated and almost secret sort of wetland, the remnant of a 6,000-year dance still happening in South Florida. Usually seen at a distance from the road, these curious assemblages known as cypress domes mark the edges of the Everglades’ central nervous system, the 50-mile-wide river that runs from Lake Okeechobee down to the southern tip of Florida. To most, they’re an unknown archipelago set deep in the subtropic borderlands. Those who have entered one will tell you they’re a bit spooky, otherworldly even. In March, I was hiking across rocky terrain on a trail 50 miles west of Miami called the Gator Hook. After picking my way through clusters of small trees, I ventured into the heart of a cypress dome, an ecological mystery that has haunted me for decades.

I’d known their doughnut-like shape since I was a kid, spying the domes in the distance when I traveled with my parents between Sarasota and Key West. I’d see those curious arrays of trees in the distance and wonder what they looked like inside. Later, I made my own periodic pilgrimages to the Keys. I started fishing out of the island community of Chokoloskee in the western Everglades, learning the backcountry north of the coast, and hiking into remote strands of the watershed looking for orchids. A decade ago, I started to write about the place, spending more time there, but as familiar as I got with it, those far-off domes still seemed mystical. Now, a fire burning nearby in the Big Cypress National Preserve pushed me east to a vein of crushed limestone called Loop Road. Even in the dry season, this area can be covered in a slow-moving sheet of water, sometimes up to four feet, but with an extreme drought blanketing South Florida, I found my way much deeper into the backcountry than I’d normally be able to hike.

As I turned south toward the dome, I saw butterfly orchids and air plants perched on the trees along its rim. And as I entered the shady half-acre wetland through a break in the dwarf cypresses that mark its edge, I was surrounded by gargantuan bald cypress trees, their bases reminiscent of ancient redwoods, littered with cyan and magenta lichen, their bark dripping with air plants just beginning to flower in delicate sprays of fuchsia, chartreuse, and lavender. I remembered then the first time I hiked alone into a dome north of the Big Cypress Reservation. That feeling of pure wonder and terror, a sensation of being watched by a panther or water moccasin. That green pool of shadows, lit up by orchids and bromeliads teeming with novelty, stayed with me, like a secret I kept.

A light rain began to fall, and the shallow pool of water in the middle of the dome, about the size of a garage, reflected the drifting clouds above. Around it, a bundle of pond apple trees swayed in the wind, and I wondered how many alligators lurked in the water. I was in another world here, inside something that felt immediately sacred. As thunder growled farther west, I was finally learning why these intricate, isolated pockets of the Everglades had always felt so mysterious to me. But soon, as I started to discover their unexpected wonders, that shapeless fascination grew into something else entirely.

In the Everglades, an area twice the size of Delaware and composed of nearly a dozen different habitats, there’s a lot to find awe-inspiring. There are prehistoric fish that have traversed its borders for thousands of years, mostly unchanged by time. Spellbinding orchids named after ghosts and cigars. It’s one of the few places where alligators coexist with crocodiles. Cypress domes, on the other hand, rarely garner the same fanfare, research, or protections as other elements in the watershed.

But in recent years, a host of revelations about the domes have clarified their significance. They play important physical, biological, and chemical roles, and provide a haven for endangered species. Although domes appear across parts of the American Southeast, they’re heavily concentrated in South Florida. More than their larger counterparts, these “little no-name wetlands [are] orders of magnitude more important” ecologically, says Matt Cohen, an ecohydrologist and the director of the University of Florida’s Water Institute. About 6,000 years ago, after the seawater that once covered South Florida had finally retreated, the Everglades ecosystem started to take shape. Not long before, the first signs of the cypress tree appeared.

The name comes from the ancient origin myth of Cyparissus, the boy who accidentally killed a tame stag and who in his grief was transformed into a cypress. The tale made the trees into a symbol of mourning and immortality—which is fitting considering that they’re among the oldest living trees on the planet. Today the oldest surviving cypresses in the Southeast are thought to date back at least 2,000 years.

The Timucua people used cypresses to make dugout canoes, and the Seminole and Miccosukee have built their houses with them. Valued for its heartwood, the tree was harvested so voraciously by the lumber industry that by the early 20th century, most of Florida’s old-growth stands of cypress had vanished.

Cohen, who has studied these wetlands for over two decades, told me that as the seasons passed and the rains came and went, a long interplay between the trees and the ground began. The leaves shed by the cypress trees decomposed in the water, generating carbonic acid that gnawed away at the limestone, creating more and more soil. Eventually, that depression in the bedrock held more water throughout the winter, enabling the trees to flourish as critters like alligators and wading birds found more habitat as well as forage during dry stretches. That continued for hundreds and then thousands of years until those once nascent cypress trees morphed into dense circular stands along the edges of a pool that can grow too deep for the trees to regenerate. From above, they can look like pockmarked canopies or neon doughnuts, but in profile, they reveal a rising and falling shape of taller, typically more mature trees closest to the center that precipitously drop back to dwarf trees along the rim.

“The cypress domes are self-creating,” Cohen said. “How often do you get to really think about this notion that an ecosystem is its own engineer?” These ecological oddities have become a sign of how the natural world adapts: The domes in South Florida are products of the depressions in the bedrock that held water in the dry season, and can also be a product of the American alligator, which searches out these sinks in the dry season, excavating the soil further and in turn becoming a collaborative engineer of the Everglades.

Cohen explained how the trees toward the center of cypress domes grew larger by excavating a pool with the “rocket fuel” that the falling leaves and resulting acid produced in the standing water—etching a deeper depression in the limestone over time, collecting more water and soil. I learned how that process then created richer and deeper soil, and how the farther you traveled out from the center, the soil lost nutrition and depth, hence the smaller trees. The periodic fires that tore through parts of the Everglades, like the Big Cypress blaze in March, decimated the trees along the domes’ borders, helping to mold their spherical shape. I learned how the same curves I saw above ground were echoed below in the soil and the erosion of the karst bedrock in a parabolic reflection.

Small depressional wetlands like these are, said Cohen, an “incredible mosaic of habitats on the landscape,” where roughly one-third of Florida’s critically endangered creatures live at some point in their life cycles. They are sanctuaries for salamanders and frogs, key components of the food chain, and serve as way stations for migratory birds that toggle between North and South America: one of the few places where you’ll see a kettle of swallow-tailed kites in spring and fall. When you enter the emerald-tinged shadows of a dome, the plants inside can be very different from those in other domes. “That’s kind of a feature, not a bug,” Cohen told me. The diversity reflects the unique ecosystem cultivated inside each one.

The domes have the crucial ability to store water, which “dramatically alters the way floodwaters move,” essentially capturing heavy rainfall and runoff, and making them increasingly valuable given the rampant development in South Florida. But he noted how these areas, when protected and allowed to behave naturally, act like a sponge, storing water and exchanging it with aquifers that provide drinking water for several million people. The domes are one of the first places where nitrogen, phosphorus, and sediment are retained, neutralized, and stored. Their peat-rich soils are remarkable carbon sinks too. Protecting one acre of these stands of trees has far more significant environmental benefits than protecting a space of similar size in a larger wetland. “They’re truly underappreciated,” says Cortney Cameron, a scientist who has studied the unique hydrology of the domes in Florida.

And still, there are fewer regulatory safeguards for them than for other wetlands. In 2023, the Supreme Court eliminated federal protections for wetlands without a “continuous surface connection” to oceans, lakes, streams, or rivers. By some estimates, more than half of wetlands throughout the United States, once protected under the Clean Water Act of 1972, are now potentially at risk. The cypress domes protected by state laws or located in national parks such as Big Cypress or Everglades National Park remain safe, but outside of Florida, a whole host of domes can now be razed and filled, eliminating some of the region’s most critical habitats. “This incremental loss of storage and habitat has consequences,” Cohen said. “It’s death by a thousand wounds.”

In South Florida, where climate change haunts every aspect of our lives and every season in subtle and sometimes volatile ways, cypress domes are under threat due to drier winters and hotter summers. This year, researchers in Florida revealed that the trees were acclimating to climate change by becoming more efficient in their uptake of water, a possible signal of their resilience in the face of inevitable shifts to the region. The domes may be a bulwark against the crisis, not only because of their carbon storage but also because in the dry season, they become an oasis: a buffet for wading birds feasting on fish trapped in their pools, a refuge for the hundreds of plants they support, and a haven for the alligators that can help create them and that depend on them for habitat.

The more time I spent hiking into different domes in southern Florida, the more awe I felt, and my sense of why the experience seemed like entering some holy or historic place grew. The intense diversity that lends the Everglades its character, the dizzying map of different ecosystems created by that dance between water and fire, soil and bedrock, became increasingly clear. It was that wild variety that Cohen told me formed the beating heart of the Everglades—what he called “hydrological heterogeneity.” I pretended to understand. But after exploring enough domes, I could see how different each one was, the catalog of air plants in one, the hallucinogenic quality of others soaked in pink lichen, the chartreuse ferns in another. Each held this primordial feeling. The mystery of why each dome was so different only deepened that feeling.

I remembered the canopy of some lit up with raptors or wading birds, the sound of owls in others, the amber columns of light shaped by the green tendrils of the trees and the tannic water colored by their leaves. I thought about the ceremony we all participate in the farther into nature we go. Out of the mist, another world seems to appear, or rather, our world appears with clarity. Beneath a peal of thunder and the wildfire burning farther west, I stood inside that dome off Loop Road and wondered what other secrets it held.