In the eastern U.S., a long absence of fire has shifted forests towards trees adapted to moist conditions, and away from fire-tolerant species that were historically dominant. Forest Service scientists are co-authors on a recent study to see how fire affects soils in pine barrens. The team found that repeated prescribed fire encourages drier soils that favor fire-tolerant trees. Additional management that clears other vegetation is also helpful.
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Partner Webinar: Science in Practice: From the Mountains to the Coast: Fire Effects on the Soils of the South
Presented by Mac Callaham, SRS Research Ecologist
Wednesday, November 17, 2021 • 9:00—9:30 a.m. ET
You can connect to the webinar through Microsoft Teams.
Some key messages from this webinar:
- For most of the last 10,000 years, the majority of the land area in the Southeastern US experienced frequent fires, which influenced forest composition and soil functions.
- During the most recent 100-200 years, fire has been excluded from a large portion of the landscape, with associated changes to forests and soils.
- What happens when fires return to ecosystems that haven’t burned for long periods of time? What are the consequences for soil processes? This presentation will present results from research on these questions in the Appalachian Mountains, the Southern Piedmont, and the Coastal Plain.
The Science in Practice webinar series is comprised of 30 minute sessions that summarize recent research with a focus on practical take-aways for land managers and practitioners.
View past Science in Practice webinars here.
Continue ReadingWebinar Recording: Natural and Prescribed Wildland Fire Impacts on Soil Health
Climate change is increasing the odds of higher occurrence rates, intensity, and severity of wildland fires in drought-prone regions. High intensity wildfires not only denude the landscape and lower the resistance of soils to surface erosion, but they also change the physical properties of soils, alter the soil microbiome, and extend the recovery timescales relative to lower intensity fires. Rain-on-burn events can magnify multiple negative impacts, such as poor water quality and debris flows. Wildland management is at a critical juncture, requiring new knowledge and innovative tools to best support the mitigation and prevention of fire-induced hazards. The Fall 2021 Meeting of the Board of Earth Sciences and Resources discussed the emerging frontiers in research and the outlook for implementing science-based tools to support equitable federal, state, and community responses to fire-induced hazards.
Continue ReadingNatural and Prescribed Wildland Fire Impacts on Soil Health, National Academy of Sciences Board on Earth Sciences and Resources Fall Meeting
Climate change is increasing the odds of higher occurrence rates, intensity, and severity of wildland fires in drought-prone regions. High intensity wildfires not only denude the landscape and lower the resistance of soils to surface erosion, but they also change the physical properties of soils, alter the soil microbiome, and extend the recovery timescales relative to lower intensity fires. Rain-on-burn events can magnify multiple negative impacts, such as poor water quality and debris flows. Wildland management is at a critical juncture, requiring new knowledge and innovative tools to best support the mitigation and prevention of fire-induced hazards. The Fall 2021 Meeting of the Board of Earth Sciences and Resources will discuss the emerging frontiers in research and the outlook for implementing science-based tools to support equitable federal, state, and community responses to fire-induced hazards.
This event is public and free to attend. More information will be posted to the event page soon.
Keynote
- Tom DeLuca, Oregon State University
Panel 1: The Effects of Natural and Prescribed Fire on Soil and Watersheds
- Brittany Johnson, University of Washington
- Luke McGuire, University of Arizona
- Kyle Blount, Washington State University
- Erin Hannon, University of Nevada, Las Vegas
Panel 2: Tools for the Mitigation and Prevention of Fire-induced Hazards
- Julie Padowski, Washington State University
- Jason Kean, U.S. Geological Survey
- Pete Robichaud, U.S. Forest Service
How to Join
Instructions on how to access the virtual event will be sent to the email you use to register prior to the session. A recording will be made available following the event.
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Prescribed Fire Effects on Soil Fertility
USDA Forest Service researcher John Butnor examined how dormant-season prescribed fire affects forest soil fertility in the months after a burn in a recent paper. While others have studied soil a year or more after a prescribed burn. Butnor’s research compares soil chemistry before burning and 1, 3, 6, and 12 months after.
Read the CompassLive article and research paper here.
Continue ReadingPartner Webinar: The effect of prescribed fire on above- and below-ground soil properties in the Ozark Highlands
The Wildlife Society and The Society of American Foresters continuing education credits (1 hour Cat 1) approved
Prescribed fire is commonly applied to meet a variety of forest management objectives, including the restoration and maintenance of Oak (Quercus spp.) woodlands. In the Ozark Highlands, private landowners, conservation organizations, and government agencies are increasingly applying fire to restore woodland sites after a period of fire suppression. Even though fire effects on vegetation, fuels loading, and wildlife habitats are often studied in the Ozark Highlands, few studies have measured fire effects on soil physical and chemical properties in this region. Since it is important to understand how prescribed burning affects short- and long-term forest soil productivity, we initiated this study to quantify prescribed fire effects on organic soil horizon measurements, physical and chemical properties of soil mineral horizons, and soil solution nutrient flux, and to resolve the time required for soil properties to return to pre-burn soil conditions. Study sites are located in the Oak-Pine Woodland/Forest Hills Land Type Association in the Black River Basin of southern Missouri. Weathered from Roubidoux sandstone and Gasconade dolomite, soils at the study sites contain large quantities of coarse fragments and reduced nutrient content.
In 2015, fire was applied to sites that had no documented occurrence of fire for at least 40 years prior and sites that had been burned twice since 2002. Sampling efforts were focused upon stands on exposed hillslopes. The percent cover, thickness, and dry weight of the Oi, Oe, and Oa horizons were measured prior to and immediately following fire, and annually for two years post-burn. Prescribed fire completely consumed the Oi horizon and partially reduced the Oe horizon, but both were recovered two years later. Mineral soil bulk density was measured at the 0-10, 10-20, and 20-30 cm depths before fire, and bulk density at the 0-10 cm depth was re-sampled two years post-burn. There was no change in bulk density of the whole soil and the fine soil fraction. Mineral soil samples were collected prior to fire treatment, immediately post-burn, and at six-month intervals for two post-burn years at depths of 0-10, 10-20, and 20-30 cm. Compared to pre-burn values, there was a significant increase in the water-stable microaggregate size fraction within stands burned for the first time in recent history. Fire did not significantly alter total mineral soil organic carbon stocks, the labile carbon pool, or the pyrogenic carbon pool for any sampling depth. There was also no fire effect on total nitrogen, soil pH, effective cation exchange capacity, base saturation, aluminum saturation, or exchangeable base cation concentrations. The soil solution was continuously monitored for one year pre-burn and two years post-burn at 10 cm and 30 cm depths using Plant Root Simulator (PRSTM) ion-exchange probes. Ammonium-nitrogen availability was significantly greater over the two post-burn growing seasons at the 10 cm depth within periodically burned stands. However, during the second post-burn growing season, phosphate-phosphorus availability at the 30 cm depth was significantly less within periodically burned stands relative to stands burned for the first time. Gravimetric soil moisture content monitored monthly at the 0-10 cm depth was not different between treatments for during the duration of the study.
The 2015 prescribed fires were generally within prescription designed for low-intensity, low-severity burning. Soils were moist at the time of fire and soil temperatures minimally increased. Study results indicate that when fuels and soils are moist at the time of fire, there is minimal immediate impact on organic and mineral soil properties. Overall, burning for the first time after a period of fire suppression did not significantly alter mineral soil physical and chemical properties. The lack of differences among treatments before fire and the minimal change in mineral soil properties following fire suggests that when given time to recover between recurring burn events, periodic burning also does not adversely alter mineral soil properties. Study results are informative and can assist Ozark land managers in developing a prescribed fire regime that meets sustainable forestry objectives.
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