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  • Writer's pictureIPWA

What the Duff?

Updated: Dec 1, 2022

By Emily Herrington, IPWA Volunteer

Let’s Talk Fire.

Imagine hiking down from a high ridge towards a crystalline alpine lake. You approach a popular backpacking area and see a smoke trail, and the acrid smell of burning wood hits your nose. You know that campfires are illegal east of the continental divide so you investigate. You find an abandoned, smoking campfire. The smoke is creeping up from the surrounding ground and the bases of the trees are charring.

The fire isn’t blazing, but it is clearly destructive. The duff layer is on fire beneath your feet.

But... What the duff?

There are two basic types of forest floor debris. Litter is the highly flammable top debris that can cause intense surface fire. Duff is the underlayer full of fungus and decomposing matter. Duff has insulation. Duff has gas build-up from degrading organic matter. With the right moisture level and heat exacerbation, duff has the potential for smoldering combustion that can last for hours, and sometimes weeks or months.

The greatest duff accumulation occurs around the base of trees. At high altitudes, as often seen in the Indian Peaks Wilderness, trees rely heavily on the duff layer at their base for vital nutrients. When the duff at the base of a tree is ignited, the result may be diminished sap fluctuation, leaf chlorophyll, and reduced carbohydrate storage in the roots – this causes lasting distress and can lead to tree death (Varner, 2016).

Duff fires often lead to forest fires as the litter is ignited. They are just as dangerous as surface fires!

So, you see a smoldering fire…

In early September, an IPWA volunteer faced this very situation. Thankfully, the USFS already had a crew on scene to mitigate the potential forest fire, but volunteer Patrick Lienin was there for a first-hand experience.

“I was coming down from Devils Thumb Pass, when a red helicopter flew into the Basin and circled around the Jasper Lake area. I later found out from the Heli crew that an earlier hiker reported smelling and seeing smoke between the trail and Jasper Lake. Coming closer to the fire, I followed the smell and checked the numbered campsites until I found the active fire location around 3:15 pm. Two firefighters and the pilot were actively trying to get control of the fire.”

The Indian Peaks Wilderness has numbered campsites around Jasper Lake, but no fires are allowed. Ever. This smoldering fire was caused by an illegal campfire near none of the designated sites.

“The extremely dry duff layer around the trees was smoldering. Though the campfire was put out superficially in the morning, the duff layer continued to burn and expanded outside the campfire ring. It was quite surprising to me how deep underground the fire was smoldering.”

Under the litter layer, the duff layer can exceed 12” deep, creating a unique fire containment situation (Varner, 2005). If the fire ring is on a duff layer, the heat and embers can cause a fire to ignite below the surface, even after it appears to be extinguished.

So I see a fire -- how do I safely put it out?

- ALWAYS check the scene for your personal safety first!

- Do NOT cover the fire with dirt. This can insulate the embers and ignite the duff!

  1. Slowly drizzle water onto the embers while stirring them. Continue until all parts have been thoroughly wetted, making a slurry of embers. Make sure all burning wood is thoroughly soaked and broken up.

  2. Carefully pour more water over the heated rocks and wet the ground underneath them. Be careful, and wear eye protection! Hot rocks can burst when exposed to cold water.

  3. Once the fire has been extinguished successfully, make sure to report to USFS. If you are recreating in Arapaho or Roosevelt National Forests or Indian Peaks or James Peak Wilderness areas, having these numbers saved to your phone is a good way to be prepared for such encounters:

IPW - Boulder County Sheriff’s Dispatch: (303) 441-4444

JPW - Gilpin County Sheriff’s Dispatch (303) 582-5511

Arapaho & Roosevelt National Forest Interagency Wildfire Dispatch Center: (970) 295-6800

Lienin stayed to help put out the fire, making many trips to and from the lake bringing water. Tough work after already completing miles of hiking. Way to go, Patrick!

"I offered my help and started using my water bottles and large water bladder to get water from Jasper Lake, about 300 ft. downhill. After about a dozen trips, the fire situation became a lot more relaxed, and we had some time to chat. At about 4 pm, the fire was declared under control and projected to be out at 6 pm. I left at 4:15 pm and told every hiker about the fire danger and dry conditions on the way down.”

If you cannot put out the fire, or it is a risk to your personal safety, call 911 and report it as soon as possible! Make sure to take note of location, size, vegetation and type of terrain.

General location (distance from trailhead or closest landmark) is generally better than direct GPS coordinates, as they can be inaccurate. Cell service is available in some areas of the Indian Peaks Wilderness, and getting in touch quickly can prevent forest fire outbreaks. Noting the closest emergency call box to your trailhead in case of emergencies is also a good practice.

Enjoying our wilderness areas comes with the honor of their stewardship. We must be responsible for our own behavior and activity, and, unfortunately, sometimes for those of others. We cannot thank Patrick enough for contributing to this article through pictures and his story. Thank you for representing the IPWA as one of our stellar volunteers!



Photos courtesy of Patrick Lienin and Emily Herrington

Mary Kalendovesky - Boulder Ranger District Wilderness Ranger

Varner, J. M., Gordon, D.R., Putz, F.E., & Hiers, J.K. (2005). Restoring fire to long-unburned pinus palustris ecosystems: Novel fire effects and consequences for long-unburned ecosystems. Restoration Ecology 13(3):536-544.

Varner, J. M., Kreye, J.K., Hiers, J.K., & O’Brien, J. J. (2016). Recent advances in understanding duff consumption and post-fire longleaf pine mortality. United States Department of Agriculture.


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