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Root Fires and Leave No Trace Campfire Building

Root Ball Fires in Maine
Root Ball Fires in Maine

I came across this note last week when I was hiking south past Rainbow Lake on the Maine Appalachian Trail.  It reads:

HELP, Aug 7 11AM, All Hikers, Towards the lake, I found a root fire. I’ve spent the past 2.5 hours digging up the ground and dumping H2O. Please take a minute of your hike to check up on the area (towards the shore, against the large mosey rock.) Forest Service is on their way. Still, please check on it even if it is raining. Thanks Cj, Abol RR MATC BSP (Ridgerunner, Maine Appalachian Trail Club, Baxter State Park).

What is a root fire?

A root fire is a fire that burns underground along the root system of a tree. It’s a very dangerous form of fire because the fire can smoulder for months underground, long after the surface part of the fire has been extinguished. Root fires can also travel underground and resurface some distance from their point of origin.

Deep Roots
Deep Roots

The threat of root fires is especially serious in forest habitats with extensive root systems, like Maine’s 100 mile wilderness. Root fires can be started by lightning strikes, campfires, or even an errant cigarette butt, and major forest fires have been attributed to them.

Leave No Trace Campfires

If you ever hike or camp in Maine, it’s important to understand the dangers of starting any kind of fire and the potential for root fires. Given the risks,  you might consider foregoing a fire or at least teaching your group how to build a leave no trace mound fire with a fire resistant cloth and a mineral soil.

To build one of these, you lay a fire-resistant cloth on the ground and then pile mineral sand, like beach or stream bed sand on top it. Once the mound is created, you build a fire on top of it, instead of bare ground. The mound creates an insulation barrier that prevents the ground under the fire from being scorched and preserves the micro-organisms or plants living there. The mound also prevents root fires because it stops the propagation of the fire below the fire-resistant cloth.

Fires can be fun, but you need to understand all the consequences of building them and learn how to do it responsibly so that others can enjoy the woods after you’ve gone. Burning down the forest in order to roast some marshmallows is not a good tradeoff. If you want to build a fire, learn how to do it responsibly and leave no trace.


  1. That explains it! Years ago I came across what must have been a small root fire in the woods near a high elevation lake in the Frank Church Wilderness in Idaho. I was completely mystified as there was no sign of any people around, it was several hundred feet up and away from the lake and off the trail, and it was not a suitable camping spot. I put it out but forgot to ask the forest rangers or other hikers about it. Thanks.

  2. I first learned about root fires in 1972 when I was an overnight camper in Maine. I remember being warned that lit cigarettes can start root fires that travel underground through the pine needles on the forest floor. I've read that root fires are also a big threat in areas that have Douglas Fir trees.

  3. I was in a Douglas Fir forest when I saw it. Sounds like they would be more common out west then because of the pine needle floors and Douglas Fir forests.

  4. Good explanation. We typically scrape down to mineral soil here in the West, but doesn’t sound like that’s an option in some place like Maine.


  5. I purchased an island 5 years ago, and the previous owner had never built an outdoor fire pit. There were piles of firewood everywhere, but he never burned it outside because he was concerned about the risk of root fires, as the ground was thick which mulch.

    My brother helped me build what we thought was a secure pit. We dug down deep enough to put in 6 large cement blocks, put in bags of sand and gravel, and rocks. We had outdoor fires for 5 years, with no problems. We had a campfire last weekend, which we extinguished well, and checked on before leaving. I got a phone call 4 days later, saying that the island was on fire. Thankfully the neighbours saw it soon, and dealt with it, or I could have lost the cottage and all of the trees.

    I think that I am too worried to try again! Where can you purchase the fire resistant cloth? Is there an even safer option?

  6. I think some morons must think a lit cigarette can’t start a fire because a lit cigarette is so small. By the time the entire human race learns the basics we’ll be long extinct.