The resinous scent of Engelmann spruce wafted over a shallow, mossy pool surrounded by lush sedges near the 11,800-foot summit of Ophir Pass, in southwestern Colorado’s rugged San Juan Mountains. This type of wetland, known as a fen, forms when perennial water saturates the ground, limiting plant decomposition and allowing organic matter to accumulate as peat.
Just downhill, however, on that hot, sunny July day, another part of the fen was visible: a degraded area, bare soil exposed on a steep slope.
Peatlands — fens and bogs — are key climate regulators. (Bogs are maintained by precipitation, but fens, which, in North America, occur in the Northeast, Midwest and Mountain West, depend on groundwater.) Their peat retains plant carbon that would otherwise decompose and be released as carbon dioxide. Despite covering only about 4% of Earth’s land area, peatlands store a third of the world’s soil carbon — twice the amount trapped in forest biomass. “Fens are old-growth wetlands,” said Delia Malone, a recently retired field ecologist with the Colorado Natural Heritage Program. Some of Colorado’s fens are over 10,000 years old.
In relatively dry southern Colorado, they also provide a secondary round of water storage. The first round is Colorado’s snowpack, which, as it melts, feeds groundwater that fens’ spongy peat captures and later releases to dwindling waterways and drying landscapes after the snow is gone.
But the steep and degraded bare patch at Ophir Pass no longer functions. Where sedges, mosses, bog birch and other wetland species should be thriving, white PVC groundwater testing wells dot the ground, and heavy straw tubes called wattles reduce water and sediment runoff into the creek below.
“Fens are old-growth wetlands.”
“This is the steepest peatland we’ve ever tried to restore, as far as I know,” said wetland ecologist Rod Chimner, a professor at Michigan Tech. In the Rockies, fens lie at high elevations, which complicates restoration. Approximately 2,000 fens have been mapped so far in the San Juans, and about 200 need work. Chimner’s Ph.D. advisor, David Cooper, began restoring the area’s fens decades ago, and together they’ve literally written the book on mountain peatland restoration. Now, Chimner and staff from Mountain Studies Institute (MSI) — a local nonprofit research and education center — are restoring an ecosystem born from the last ice age but damaged by bulldozing in the 1970s.
Dams, road-building and other human activities harm Colorado’s fens, which can take 1,000 years to build just 8 inches of peat soil. The Ophir Pass fen is a rare iron fen, fed by groundwater rendered acidic by iron pyrite. The resulting chemistry supports unique plant communities — and leaves iron and other minerals incorporated in the peat or deposited in hardened layers. This fen was likely damaged by bog iron mining, which has degraded several iron fens in the San Juans.
CLOUDS STARTED TO BUILD as workers used hand saws to extract plugs of sedge and soil from a healthy, already restored part of the fen. Like Goldilocks’ bed, the plugs have to be just right: Too large or too many, and digging them up disturbs the soil surface; too small, and they won’t survive transplantation. “As long as it has at least one rhizome, it will plant and spread,” said Lenka Doskocil, a research associate with MSI’s Water Program and Chimner’s graduate student. She split a plug, revealing rhizomes embedded in the rusty-brown peat, then nestled it into a bucket of plugs. Sometimes, workers plant nursery plugs or greenhouse starts from seeds collected in the area.
Chimner and Doskocil hauled the first bucket of plugs up to the bare patch, began digging small, regularly spaced holes, then gently inserted one sedge plug per opening. A stiff breeze provided relief as several other people joined in. “Take your time and do it right,” Chimner said encouragingly as he stepped back to observe. Otherwise, the plugs wouldn’t take.
Doskocil spotted an older plug protruding from the soil. But it wasn’t from rushed planting: Frost heave, a freeze-thaw cycle that thrusts soil upwards, had kicked it out of the ground, she said, tucking it back in. Frost heave complicates planting and breaks rhizomes, preventing nearby plants from colonizing bare soil. But Chimner’s past research has yielded a solution: Team members insulated the surface around each newly transplanted sedge with Excelsior, a shredded aspen mulch tough enough to withstand several winters. “We’re giving them little down jackets,” Chimner said.
A rhythm of extract-portage-dig-plant-mulch ensued as the iron-painted ridge of Lookout Peak towered to the north. A passenger yelled “thank you” from a truck descending the pass. Doskocil broke open a handful of peat, revealing roots that were hundreds of years old, if not older.
Planting the steepest quarter acre here has been difficult, and a 2021 fire didn’t help. “We’re kind of starting all over again” in that section, Chimner explained. They’re experimenting with direct seeding, which is common in wetland restoration, but challenging at the high-elevation site. “I’ve seeded here three times,” said Haley Perez, a community science program assistant with MSI.
“This is the steepest peatland we’ve ever tried to restore, as far as I know.”
Conservation biologist Anthony Culpepper, associate director of MSI’s Forest Program, gestured uphill toward what used to be a bare “Mars slope.” He listed the challenges: timing, winds that blow seeds away, variable winter and monsoonal precipitation, a short growing season, a sunbaked slope and animals that eat the seeds. Still, over many seasons and with multiple collaborators — several federal agencies, San Juan National Forest, Purgatory Village Land, the National Forest Foundation, San Juan Citizens Alliance and others — they’ve made great progress. That former Mars slope is now covered with mat-forming, soil-stabilizing wetland plants, including rare species.
The fen is wetter from strategic placement of wattles and check dams, wooden slats that slow surface water flow so that it soaks into the ground instead of running straight downhill. In turn, more groundwater has enabled transplantation and spread of thousands of plants. Much of the fen is now green, with mosses and other vegetation colonizing on their own. “This is the first time I’ve seen arnica at the site,” said Culpepper, who also noted the lack of invasives, a promising sign.
MSI takes an adaptive approach to restoration: Research guides planning and execution, and outcomes are carefully monitored to guide future work. That’s important in a region and state where rising temperatures and declining snowpack are predicted to lower water tables, which could disrupt new peat formation and even promote peat decomposition, potentially shifting some fens from carbon storage to carbon release. “How do we get our systems to a spot where they’re resilient enough to withstand the challenges that are going to continue to come?” asked Doskocil. MSI and its collaborators are working on it — at Ophir Pass; at Burrows Fen, a new project north of Silverton; and elsewhere throughout the San Juans.
Fat raindrops landed as the group debated whether to secure the mulch with a layer of jute netting. A wind gust decided it; they added the netting and then, just as the sun returned, trooped uphill to their vehicles to head home. Someone asked Chimner if he was satisfied with the day. “When I can look down and see all green, I’ll be satisfied,” he replied.
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This article appeared in the October 2025 print edition of the magazine with the headline “Fen fixers.”
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