While Western forestry experts accept some wildfire as redemption for the landscape, they’ve also learned that out-of-control megafires can do more harm than good. Now a new study puts a spotlight on the small, cartoon-cute creatures ready to serve as a stalwart defense against raging, 100,000-acre firestorms: the humble, hardworking beaver.
This story first appeared in The Outsider, the premium outdoor newsletter by Jason Blevins.
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River segments hosting beaver-created dams fared far better during and after megafires than riverscapes without beaver activity, leaving pockets of intact habitat crucial for wildlife, and protecting waterways from runaway erosion, a study published in The Geological Society of America in January found.
“Every presentation I’ve seen the last handful of years that has to do with these big fires, there’s an … aerial photo of a sea of black with this green island in the middle,” said Clay Ramey, fisheries biologist for the Aspen-Sopris Ranger District, who was not an author of the study. “That’s the beaver pond.”
The study, led by University of Minnesota Twin Cities ecohydrologist Emily Fairfax, investigates three megafires that took place partially or wholly within Colorado borders in 2020 — Cameron Peak, East Troublesome and Mullen — which together burned 579,603 acres.
Using a combination of infrared and optical satellite imagery, as well as field observations, a team of nine scientists assessed the burn severity along streams within the fire scars. They then compared reaches of stream that had beaver dams to stretches without, and to the surrounding forest.
“Beaver-modified riverscapes are resistant to megafire-scale disturbance,” the authors wrote. “This resilience is directly attributable to beaver dam- and canal-building activity.”
There are many related benefits for native plant species, terrestrial and aquatic wildlife, river health and human communities downstream of the burn scar, according to researchers. In fact, beaver habitat is proving so valuable for wildfire mitigation and restoration that restorationists are imitating these rodents across the state.
The problem with megafires
With the right frequency, severity and distribution, wildfire benefits the landscape immensely. But there’s good fire in the American West, and bad.
Good fire is generally low or mixed severity, periodically cleansing forests and mountain ecosystems of deadfall and opening up the understory. These burns spur new growth of native plants and thereby fresh, nutritious forage for animals. Historically, the natural fire regime in the Rockies yielded forests that, if viewed from the air, looked more like patchworks of meadows, wetlands and tree stands of various species. These mosaics of habitats, paired with frequent-enough burns, meant that wildfires generally moved more slowly across the land and didn’t burn as consistently hot. Wildlife also had plenty of places to hide from the flames and the landscape recovered in a matter of years.
But megafires generally fall under the “bad” classification.
These 100,000-plus-acre fires flare in the driest summers, blown up by gale-force winds. Despite being historically rare, megafires have increased in frequency in recent years.
“These fires pose unique challenges,” the study states. “They have exceptionally fast rates of spread; they generate self-sustaining weather systems; and they can easily cause secondary ignitions in the surrounding landscape via ember spotting and lightning strikes from pyrocumulus clouds.”
Once sparked, megafires are a near-unstoppable threat to human life and property, spreading tens of thousands of acres in a day with the right conditions. And they can burn so hot that they incinerate all vegetation and render soil hydrophobic. Recovery can stretch across decades in such cases.
These blazes, while less frequent than smaller wildfires, “account for a disproportionately large amount of property damage, habitat destruction, fatalities, and fire-fighting costs,” the authors write. In large part, megafires result from poor forest management and fire suppression over the last century, as well as human-caused climatic warming that has yielded hotter summers and more extreme weather.
The aftermath of a megafire can be as bad as the fire itself.
Landscapes stripped of vegetation are prone to destructive and lethal flooding and debris flows.
With spring runoff or summer thunderstorms, any water that dashes down a steep enough slope gains momentum, picks up sediment and ash, and carries these particulates to the nearest stream. Without anything to break its momentum, the catching stream erodes viciously, cutting into its banks and running black. So long as the momentum keeps up, the sediment and ash remain suspended and continue downstream, coating the gills of fish, blowing out aquatic insects and clogging up the intakes of river-drawing municipal water treatment plants.
This was true for the cities of Fort Collins and Greeley, both of which source drinking water from the Poudre River, whose watershed was severely burned by the Cameron Peak fire.
According to Hally Strevey, executive director for the Coalition for the Poudre River Watershed, since May 2021, Fort Collins has had a total of 133 days where they could not treat the water from the river because it was so sediment filled. Their longest intake outage was 40 days in 2021 after the Black Hollow flash flood event and debris flow, which killed four, wrecked six homes and gutted the local trout population. Greeley has had similar water quality issues.
Fortunately, both cities have some redundancy, with multiple water sources, treatment plants and holding ponds that offer some buffer when the rivers run high with sediment.
“It’s worth noting that not all water providers have this advantage,” Greeley’s acting deputy director of water resources Kelen Dowdy wrote.
For municipalities with fewer sources of water, an upstream wildfire can spell disaster.
Firefighting beavers
If a megafire hits, the damage runs so deep that a forest must practically start over. So, the fact that beaver wetlands weather these tempests virtually unscathed is a big deal. These green islands represent a jumping-off point of recovery for wildlife and plant life.
The reason beaver ponds have such fortitude against wildfire has to do with the hydrology they enact. Beaver dams hold back water and beaver canals spread it out. The weight of the pond presses water into the ground and out over a broad swath of the valley floor, raising the water table and increasing soil moisture. The result: a verdant valley bottom that doesn’t burn.
These green islands constitute fire refugia: patches that either don’t burn, or burn at a low-enough severity that wildlife can hide there while the fire rages, and where these same animals can find food, water and shelter afterward, when the rest of the forest is char black.
“Today, in the mountains — and especially in the river corridors — there’s very little fire refugia that’s reliable outside of the beaver wetlands,” Fairfax said. “They’ve become this disproportionately important source of healthy habitat.”
About 80% of terrestrial species in the intermountain West need access to riparian wetlands for some portion of their life cycle, Fairfax said. In the aftermath of a megafire, the intact habitat of green beaver wetlands is all the more important for maintaining precious biodiversity.
And beaver wetlands can help fight fires as well, serving as “speed bumps” to slow the spread or even function as fire breaks to help firefighters contain lower-intensity burns.
“Beavers are built-in fuel thinners,” Fairfax said. “They cut trees. So even when you’re not in the pond … they are still harvesting the surrounding area and thinning that fuel out. So they really do create this multilayered fire resistance.”
Fairfax and her coauthors frame beavers and their landscape engineering as an overlooked partner in mitigating and fighting wildfires. They argue that “shifting a portion of fire-management focus to making landscapes less favorable for megafires seems to be a prudent course of action.”
Prescribed burns are a well-known method of rendering the landscape less favorable to megafires, restoring its historical fire regime.
Like a doctor prescribing medication to a sick patient, human-prescribed fire is our attempt to nudge the land back toward its patchwork or mosaic state, rather than the de facto monoculture forests we know today, according to Dan Nielsen, the central zone prescribed fire and fuels specialist for White River National Forest. The mosaic makes it more difficult for fire to spread quickly, slowed by every change in habitat, as well as by diminished fuel availability.
Another method? Restore the land’s natural beaver regime, Fairfax said.
North America is home to only 10% of its pre-settlement beaver population. Before the fur trade of the 1500s-1850s nearly extirpated beavers, scientists estimate the land held 100 million to 400 million. And a beaver dominated landscape would have looked drastically different than what is thought of today as “pristine.”
“Thanks in part to beavers, ours was a watery country, a matrix of ponds and swamps, marshes and wetlands, damp mountain meadows and tangled bottomlands,” Ben Golfarb writes in “Eager: The Surprising, Secret Life of Beavers and Why They Matter.” The American West has lost 90% of its historical wetlands since European settlement, Fairfax said; 50% in Colorado, according to the Colorado Wetlands Information Center.
In their heyday, beavers may have submerged up to 300,000 square miles of North America — more land than the state of Texas, the National Park Service says.
This was the natural, healthy state of the American West for thousands of years. And simply put, that much water on the land has quite the dampening effect for large wildfires.
Partnering with beavers for next the fire
However, beavers have a bad rap, especially among agriculturalists, for whom the rodent is notorious for damming of irrigation ditches, toppling of prized trees, and flooding of property.
“I want to fully acknowledge that it’s hard sometimes to live next to them,” Fairfax said, adding that new techniques have proven coexistence with beavers a real possibility. Only in recent years has the value of beaver activity to wildlife, human communities, and agriculture become more widely recognized.
In a 2021 paper, Fairfax and coauthor Chris Jordan drew on 144 studies to argue that beavers constitute a key climate solution in North America. Beaver wetlands, the authors explain, serve as carbon sinks, fire buffers, biodiversity hotspots, drought banking, flood attenuation and water filtration.
“When we reconnect streams and rivers to their floodplains [through beaver activity], we perform both climate mitigation work (slowing/stopping the trajectory of global warming) and climate adaptation work (building resilience and resistance to climate driven disturbances that are already occurring),” they write.
Such climate-driven disturbances include flood, fire and drought, all of which worsen with each fraction of a degree the climate warms.
FROM LEFT: A post-assisted log structure , or PALS, built in the fall of 2023, spans a channel on Brush Creek in Eagle. It was adopted by a beaver a few months later. The water behind the beaver-adopted PALS is already 3 feet higher, helping to raise the water table and to drastically speed along restoration efforts. (Courtesy of Eagle River Coalition)
FROM TOP: A post-assisted log structure , or PALS, built in the fall of 2023, spans a channel on Brush Creek in Eagle. It was adopted by a beaver a few months later. The water behind the beaver-adopted PALS is already 3 feet higher, helping to raise the water table and to drastically speed along restoration efforts. (Courtesy of Eagle River Coalition)
Beaver habitat especially benefits agriculture when beavers live upstream. Some studies have shown that beaver dams reduce the severity of flooding by forcing the water to slow and spread out, reducing momentum and damage downstream. By the same token, dams store this water, meting it out over drier periods, meaning more instream flow to water cattle or crops in the August heat.
And in wildfire recovery, beaver-engineered riverscapes provide huge benefits.
When the Cameron Peak fire burned 208,913 acres, becoming the largest wildfire in Colorado history, the Poudre River Watershed suffered greatly. Communities and stakeholders that rely on the Poudre have been playing catch-up ever since to restore and build resilience into the watershed ahead of the next fire.
In her role leading the Coalition for the Poudre River Watershed, Hally Strevey helps orchestrate huge collaborative efforts of more than 30 partner organizations from the state level down to nonprofits as they work to revitalize the Poudre.
This is where the field of low-tech process-based restoration enters the picture. The approach includes a raft of methods that aim to nudge degraded waterways back to health by mimicking natural processes, then letting nature do the work.
In contrast to highly engineered restoration projects that cost millions and involve heavy machinery, low-tech process-based restoration relies on natural processes that have been at work in American rivers for millennia, such as logjams and beaver dams.
“The whole core of low-tech process-based restoration … is that we are trying to nudge the river back to a place where it can take care of itself,” Fairfax said. “It’s never meant to be like we are controlling the river. It’s more that we’re feeding the river so that it can get healthy again and feed itself.”
Low-tech process-based restoration takes its cues directly from nature, Fairfax points out. And the approach is rooted in the humility that humans may not know what’s best for a river.
“I don’t know that we know exactly what we should make [a river] look like today,” she said. “And I don’t think we have to know what it should look like today, because if we nudge the river back to taking care of itself, it will figure out what it should look like today just through natural physical and biological processes. We don’t have to design all the way to the finish line. We just have to design enough to get it going.”
One technique being implemented in the Poudre River Watershed is installation of post-assisted log structures constructed from untreated lumber driven into the streambed and logs piled upstream against them.
These structures function like logjams, breaking the momentum of a stream, spreading water into the soil, and slowing the stream so sediment drops out. These faux logjams also add to stream complexity, creating riffles and pools, side channels and slack water, all of which benefit aquatic insects and native cutthroat trout.
With funding from the Colorado Department of Public Health and Environment, the Poudre coalition has installed several post-assisted log structures on Upper Elkhorn Creek, one of the river’s tributaries. Working in a relic beaver meadow, they strategically placed these logjams where the stream had breached a series of old beaver dams. Strevey said the hope is to prevent the wet meadows from unraveling and to draw beavers back.
“When beavers show up, restoration goes a lot faster,” Fairfax said. “But in some places, it’s hard to get the beavers to come back.”
For streams that are heavily impaired by grazing, stripped of riparian vegetation, and have cut their way down into the floodplain, a boost from some form of process-based restoration may be the first step in bringing a stream back up to snuff for beavers.
Post-assisted log structures are being deployed elsewhere in the state too, such as just upstream of the town of Eagle on Brush Creek. Eagle County Open Space and the Eagle River Coalition have collaborated to install 24 such structures on a half-mile stretch of creek since 2022, according to county Open Space Manager Peter Suneson.
The idea is to reintroduce complexity to an otherwise simplified and impaired creek that is disconnected from its floodplain.
“Reconnecting streams with their floodplains helps ‘rewet the sponge,’ meaning during high water events, the water that gets onto the floodplain can slow down and infiltrate into the groundwater,” wrote Anna Nakae, watershed restoration manager for the Eagle River Coalition.
“Rewetting the sponge” also sets the stage for beavers’ return by raising the water table, in turn fostering the growth of a primary food source: willows.
Although bringing beavers back isn’t the explicit goal of the Brush Creek project, Suneson said, “We’ll be stoked if they naturally move in … and bring with them the ecological benefits inherent to a keystone species.”
A beaver adopted one of their channel-spanning log structures in November, and already the creek is reconnecting to its floodplain.
This is what Clay Ramey is trying to do on a heavily grazed stream near Rifle using beaver dam analogues, or fake beaver dams, that behave hydrologically like the real thing.
Ramey and his team have installed 10 of these beaver dam mimics, with more planned for this coming summer, the aim being to bring enough life back to a limping creek that beavers can once more look after it.
Even if beaver don’t immediately return, post-assisted log structures and beaver dam analogues capture much of their benefits. These human-built structures pave the way for the return of beavers and the enduring green islands they create.
As Fairfax points out, when beavers do show up, the work goes much quicker and requires far less human intervention.
