Even though the fires are out and the smoke is gone, Montanans are not out of the woods yet. Randy Davis, a soil scientist with the Forest Service’s Burned Area Emergency Response Team, says that people living downstream from badly burned areas face the threat of erosion, heavy sedimentation, well contamination and mudflows for at least the next 3-5 years and quite possibly the next 5-10 years. Based on projections of fire seasons like this year’s, Davis says that full hydrological recovery, which occurs when there is enough vegetation to hold the soils firmly in place, is probably 25 years in the future.
“In an undisturbed forest, soil erosion is a positive thing,” Davis says. “The problems arise when the system gets out of whack—as is the case after a severe fire season.”
Fearing a wet spring and massive runoff, the Forest Service will be upsizing culverts on many of the forest roads. To stem erosion on the burned slopes themselves, the Forest Service has been “contour falling” trees. It is hoped that trees laid down the contour of a hillside, ditched on the uphill side and staked in place, will provide a barrier for the flow of materials. This may also form areas where seeds and nutrients can collect and be the first places to green up in the spring. Where trees are in short supply, flexible tubes made of biodegradable netting and filled with straw will be used. And finally, bale bombing—the practice of dropping 55-pound straw bales from a helicopter up to eight at a time—will provide a protective layer that will hopefully keep the soil from moving.
Most of these erosion control measures are designed to help rivers and riparian areas recover from a season of fire more rapidly. The real problem, notes Davis, is that there are a lot more people living in the woods these days.
“The system is already aggravated by the encroachment of humans,” Davis adds, “and that is where you see cataclysmic events such as mudflows carrying cars and houses down the sediment-loaded rivers.”
Davis suggests that anyone living directly downstream from badly burned areas should keep an eye on the erosion occurring above them. Since the Forest Service practices erosion control only on federal lands, private landowners should contact the Natural Resources Conservation Service, which can help with assessment and technical support. The Conservation District and County Extension offices are also good places to turn for help in keeping your hillside where it belongs.