Boulder’s unique natural areas have evolved with fire. While fire has long been an important component in maintaining healthy ecosystems, it is also a natural risk for our community. Learn more about how the City of Boulder works to manage wildfire risks on Open Space and Mountain Parks (OSMP).

Fire Has Shaped Boulder's Unique Natural Areas

We live in an area that has evolved with fire for millions of years. In fact, research shows areas around Boulder frequently burned, helping to shape the diverse wildlife and plant ecosystems we all enjoy today.

However, hundreds of years of ecological disturbances – such as fire suppression across the West – have altered nature's delicate balance, creating natural hazards that can fuel fires. With climate change creating conditions in which fire is a year-long concern, out-of-balance ecosystems can cause future fires to burn hotter and further tip nature's balance out of whack.

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Trees on city open space north of Boulder

Preparing For the Risk of Wildfire on Open Space

Fire is a natural force that is both dangerous for our community and can be beneficial for native ecosystems.

We live in a location where the wildfire threat is real. Wildfires happen frequently. A wildfire that poses a risk our community is not a matter of if, but when. For decades, City of Boulder Open Space and Mountain Parks has been working together with the community to address shared fire risks by:

  • Maintaining healthy natural areas that can help reduce the risk of dangerous fires. Boulder Open Space and Mountain Parks (OSMP) fire risk management mimics fire's natural processes and includes tree thinning, livestock grazing, prescribed burning and weed management.

  • Working to prevent fires on open space by enforcing regulations that prohibit all sources of ignition, including smoking, campfires and fireworks. OSMP Rangers and OSMP staff are trained wildland firefighters and help fight fires on open space. The department also works with other public land agencies to remind visitors to recreate responsibly to prevent wildfires.

Read a city guide (PDF) to help residents prepare their families, homes, and property against the year-round threat of wildfires. The most effective fire mitigation efforts are those completed within 5 to 10 feet of a structure. That work should remove flammable materials and establishing a fire-resistant buffer.

A Boulder wildland firefighter puts out hotspots during NCAR Fire

Thank you Boulder Fire-Rescue firefighters, OSMP Rangers and OSMP wildfire response staff – and the many agencies along the Front Range – who have battled recent fires in Boulder County.

Managing Fire Risks with Healthy Ecosystems

Tree Thinning

Since adopting the Forest Ecosystem Management Plan in 1999 PDF, City of Boulder Open Space and Mountain Parks (OSMP) has worked to mimic fire disturbances by selectively cutting trees and limbs in open space areas along Boulder's mountain backdrop. OSMP evaluates forest ecosystems to guide its ongoing tree thinning efforts – with OSMP prioritizing fuel mitigation work next to residential neighborhoods. Over the last 10 years, OSMP has conducted forest thinning work across 2,000 acres, helping to reduce vegetation that can fuel fires and improve forest health.

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Forest thinning helps to reduce fire risks and improve ecosystems

A member of the city's Forest Ecosystem Management crew thins trees south of Boulder. Tree thinning helped slow the recent NCAR Fire and keep it from becoming a more intense fire.

Livestock Grazing

OSMP partners with local ranchers to conduct prescribed livestock grazing across 500 acres just south of the National Center for Atmospheric Research. Livestock grazing helps decrease the heavy buildup of dead grass and thatch created by invasive tall oatgrass weeds, which can harm more resilient native grass species. Grazing also occurs on an additional 13,985 acres of OSMP-managed agricultural lands east of Boulder, helping to reduce vegetation across the area. Watch a recent city presentation on how livestock grazing helps to improve native ecosystems and reduced fuels during the recent NCAR Fire.

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Livestock grazing in the NCAR area

Cows graze on city open space near the National Center for Atmospheric Research. Livestock grazing helps to remove invasive weed species and reduce vegetation that can fuel fires.

Prescribed Burning

The City of Boulder periodically conducts prescribed burns to reduce fire danger for the community, improve forest and grassland ecosystem health and maintain agricultural water infrastructure. By introducing prescribed fires, the City of Boulder can restore the natural balance for Colorado’s fire-adapted ecosystems and reduce the amount of fuel during a wildfire. If a burn can’t be done safely or meet city burn goals and state-mandated guidelines, it won’t be carried out.

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Prescribed burning on Shanahan Ridge

A Boulder Fire-Rescue firefighters puts out hot spots during a prescribed burn on Shanahan Ridge south of Boulder. Prescribed burning can help restore the natural balance for Colorado’s fire-adapted ecosystems and reduce the amount of fuel in the forest during a wildfire.

Weed Management

Native plant communities across the city's open space system are more resilient and resistant to fire. However, they face challenges from invasive weed species that can harm them. For example, tall oatgrass can form dense stands that prevent native vegetation from receiving light, moisture and nutrients. Since 2015, OSMP has used livestock grazing to reduce the weeds south of the National Center for Atmospheric Research and on Shanahan Ridge.

Broadly, OSMP uses an integrated weed management approach to reduce noxious weed populations and prevent their spread by mechanical, biological, cultural and chemical controls. Examples include:

  • Mechanical: Weed pulling, weed whacking and digging.
  • Biological: Grazing.
  • Cultural: Seeding with native plant species.
  • Chemical: The judicious use of herbicides.

OSMP focuses on managing these state-designated noxious weeds including, but not limited to, invasive species, such as: Mediterranean sage, purple loosestrife, knotweed, hairy willow-herb, cut-leaf teasel, and oxeye daisy. In 2021, OSMP removed invasive weed species across more than 6,000 acres of land.

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OSMP vegetation stewardship staff removing noxious weeds

Boulder Open Space and Mountain Parks' vegetation stewardship staff remove the noxious weed, myrtle spurge, from city open space.

Fire Risk Challenges

Addressing wildfire risks in natural areas is challenging. Some of these challenges include:

  • Available budgets. The costs associated with managing vegetation on just one acre of open space land – such as fuel, labor and material costs – are significant.

  • Mowing creates its own challenges. Extensive mowing can disturb the natural balance of sensitive ecosystems. It can make them less resilient, potentially exacerbating fire risks while also harming sensitive wildlife and plant habitats. At the same time, mowing doesn’t necessarily reduce the fuel load in an area. If the grass is simply cut or weed-whipped the fuel is just “rearranged” and will likely remain on the site because of the prohibitive costs in hauling it away.

    Extensive mowing can also:

    • Harm water quality and soil health, and cause erosion and dust storms across the landscape under dry conditions, which the Boulder area has seen and will continue to see in the future.

    • Cause vegetation can grow back quickly and more densely than before.

    • Harm native grass species, which can allow aggressive weed species to dominate an area.

    • Spark a wildfire given the warm and dry conditions we are currently experiencing.

  • Prescribed burning is not always an option. Wet springs and dry falls can drastically limit the number of days available for prescribed burning. In fact, those conditions prevented the City of Boulder from conducting planned burns over the last two years. Burning and smoke restrictions can limit the number of burning days in any given year.

  • Some thinning projects can't start. Finding an outlet for wood, chips and slash is often a limiting factor in completing forest restoration projects.

The most effective fire mitigation efforts are those completed within 5 to 10 feet of a structure. That work should removing flammable materials and establishing a fire-resistant buffer.

Preventing and Responding to Fires on Open Space

Fire Rules and Regulations

All sources of ignition including smoking, campfires and fireworks are prohibited on City of Boulder Open Space and Mountain Parks lands.

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All sources of fire ignitions are prohibited on Boulder open space

Open Space Fire Crews

Open Space and Mountain Parks (OSMP) Rangers are trained wildland firefighters. Many other OSMP staff members including the department's Forest Ecosystem Management crew are also "red carded," meaning they are trained to fight fires. In all, 40 OSMP staff members have worked to battle recent wildfires. During recent fires, OSMP Rangers played a critical role in helping visitors get off open space trails and assisted with evacuating residents from their homes.

The City of Boulder is fortunate to receive assistance from neighboring communities when we conduct prescribed burns and when fires occur around Boulder. Recently, 50 other agencies supported our community during the 2022 NCAR fire. Boulder Fire-Rescue and OSMP crews also support other communities when they need help.

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OSMP staff help fight the recent NCAR Fire

Boulder Open Space and Mountain Parks (OSMP) Rangers and many other OSMP staff members have "red cards," which means they have been trained to fight wildfires.

Trails as Fire Roads and Fire Breaks

Many of Open Space and Mountain Parks' trails serve as fire roads such as NCAR-Bear Canyon – providing fire trucks critical access to Boulder's mountain backdrop. During the recent NCAR Fire, open space trails helped firefighters respond to the fire and served as "fire breaks," which can help limit the spread of fire.

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Open space trails serve as fire roads

Open Space and Mountain Parks trails play a critical role in providing emergency vehicle access along Boulder's mountain backdrop.

Responsible Recreation Reminders

Visitors should consider several critical “know before you go” guidelines before visiting open space:

  • Know fire regulations that apply to the area you plan to visit. Officials will issue citations to anyone who violates fire regulations meant to protect shared public lands and visitors.

  • Know the current fire risk. Check all fire restrictions and fire bans instituted by local authorities and public land managers.

  • Create a plan. Look at the weather forecast. Download a trail map and carry a print map. Create a plan for adverse weather or emergencies, such as fires and floods. Know where you are going and consider alternative routes you can take to leave the area. Access public land websites – including Colorado Trail Explorer (COTREX) – to view critical advisories and trail maps.

  • Charge your phone. Make sure your phone is charged in case you need assistance or there is an emergency. But remember: Cell service may be extremely limited in mountain locations.

  • Pack for changing conditions. Bring enough food and water. Wear appropriate clothing and shoes.

  • Don’t take unnecessary risks. Consider not visiting public lands during adverse weather conditions.

  • Stay alert when on the trail. Be aware of your surroundings. Always stay focused on what’s in front and around you as the outdoors are changing environments and natural hazards may be present. Call 911 if there is an emergency, such as a fire starting or if you see smoke. Try to text 911 if you don’t have enough cell service to get a phone call through.

The Challenges of a Changing Climate

The NCAR Fire (March 26, 2022) occurred under much less extreme weather conditions than the Marshall Fire (Dec. 30, 2021). Completed mitigation work in the fire areasuch as forest thinning and livestock grazing combined with fast actions from first responders helped slow the burn and keep it from becoming a more intense fire.

But we face challenges in the years ahead:

  • Continuing extreme drought conditions and increasing temperatures will dry out soil and vegetation, making them more susceptible to fire. A warmer atmosphere also holds more water in the air, evaporating it from soils and plants.
  • Boulder's unique geography – where the plains meet the mountains – will continue to fan fast winds that can blow as fast as 115 miles per hour, like what occurred during the recent Marshall Fire.

If all those conditions combine with a spark, fire can quickly overwhelm all preventative land management strategies, making pro-active community member preparedness absolutely essential.