When It's Hot, It's Hot... Or Maybe It's Not! (Surface Flaming May Not Portend Extensive Soil Heating)

1992 ◽  
Vol 2 (3) ◽  
pp. 139 ◽  
Author(s):  
RA Hartford ◽  
WH Frandsen
Keyword(s):  
Forest Floor ◽  
Fire Severity ◽  
Mineral Soil ◽  
Soil Surface ◽  
Fire Effects ◽  
Fire Intensity ◽  
Surface Moisture ◽  
Long Duration ◽  
Key Variables ◽  
Duration Of Heating

Fire effects on aplant community, soil, and air are not apparent when judged only by surface fire intensity. The fire severity or fire impact can be described by the temperatures reached within the forest floor and the duration of heating experienced in the vegetation, forest floor, and underlying mineral soil. Temporal distributions of temperatures illustrate heat flow in duff and mineral soil in three instrumented plots: two with slash fuel over moist duff and one with litter fuel over dry duff. Fires in the two slash fuel plots produced substantial flame lengths but minimal heating in the underlying mineral soil. In contrast, smoldering combustion in the dry duff plot produced long duration heating with nearly complete duff consumption and lethal temperatures at the mineral soil surface. Moisture content of duff and soil were key variables for determining f i e impact on the forest floor.

scholarly journals Long-Duration Soil Heating Resulting from Forest Floor Duff Smoldering in Longleaf Pine Ecosystems

2020 ◽  
Vol 66 (3) ◽  
pp. 291-303 ◽  
Author(s):  
Jesse K Kreye ◽  
J Morgan Varner ◽  
Leda N Kobziar
Keyword(s):  
Forest Floor ◽  
Longleaf Pine ◽  
Mineral Soil ◽  
Fire Effects ◽  
Soil Heating ◽  
Southeastern Us ◽  
Long Duration ◽  
Organic Horizons ◽  
In Fire ◽  
Experimental Burns

Abstract Prescribed fire is commonly used in southeastern US forests and is being more widely applied in fire-prone ecosystems elsewhere. Research on direct effects of burning has focused on aboveground impacts to plants with less attention to belowground effects. We measured soil heating during experimental burns in longleaf pine sandhill and flatwoods ecosystems in the southeastern US. Soil heating was minimal in frequently burned sites. Where fire had been excluded for several decades, however, we detected substantial soil heating sustained for considerable durations. Long-duration heating was most prominent where accumulated forest floor duff (Oe and Oa organic horizons) was deepest, particularly at the base of mature pines in long-unburned sites. Temperatures potentially lethal to plant tissues (≥60°C) were sustained for several hours as deep as 10 cm near pines in flatwoods sites. Sustained temperatures ≥300°C, when impacts to soil nutrients can occur, were observed for up to 35 min at mineral soil surfaces. Patterns of heating were similar in long-unburned sandhill sites; however, temperatures were generally lower and durations more brief. Heat transfer resulting from smoldering in forest floor duff deserves further attention to predict mineral soil heating, forecast fire effects, and inform restoration efforts in fire-prone ecosystems.

scholarly journals Vegetative and Edaphic Responses in a Northern Mixed Conifer Forest Three Decades after Harvest and Fire: Implications for Managing Regeneration and Carbon and Nitrogen Pools

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1040
Author(s):  
R. Kasten Dumroese ◽  
Martin F. Jurgensen ◽  
Deborah S. Page-Dumroese
Keyword(s):  
Prescribed Fire ◽  
Forest Floor ◽  
Fire Severity ◽  
Mineral Soil ◽  
Habitat Type ◽  
Larix Occidentalis ◽  
Shrub Species ◽  
Silvicultural Practices ◽  
C And N ◽  
C And N Pools

Research Highlights: This experiment compares a range of combinations of harvest, prescribed fire, and wildfire. Leveraging a 30-year-old forest management-driven experiment, we explored the recovery of woody species composition, regeneration of the charismatic forest tree species Larix occidentalis Nutt., and vegetation and soil carbon (C) and nitrogen (N) pools. Background and Objectives: Initiated in 1967, this experiment intended to explore combinations of habitat type phases and prescribed fire severity toward supporting regeneration of L. occidentalis. At onset of the experiment, a wildfire affected a portion of the 60 research plots, allowing for additional study. Our objective was to better understand silvicultural practices to support L. occidentalis regeneration and to better understand the subsequent impacts of silvicultural practices on C and N pools within the vegetation and soil. Materials and Methods: We categorized disturbance severity based on loss of forest floor depth; 11 categories were defined, including controls for the two habitat type phases involved. We collected abundance, biomass, and C and N concentrations for the herbaceous layer, shrubs, and trees using nested quadrats and 6 to 10 experimental units per disturbance category plot. Moreover, we systematically sampled woody residue from transects, and forest floor, soil wood, and mineral soil with a systematic grid of 16 soil cores per disturbance category plot. Results: We found that (1) disturbance severity affected shrub species richness, diversity, and evenness within habitat type phases; (2) L. occidentalis regenerates when fire is part of the disturbance; (3) N-fixing shrub species were more diverse in the hotter, drier plots; (4) recovery levels of C and N pools within the soil had surpassed or were closer to pre-disturbance levels than pools within the vegetation. Conclusions: We confirm that L. occidentalis regeneration and a diverse suite of understory shrub species can be supported by harvest and prescribed fire, particularly in southern and western aspects. We also conclude that these methods can regenerate L. occidentalis in cooler, moister sites, which may be important as this species’ climate niche shifts with climate change.

scholarly journals Remote sensing techniques to assess active fire characteristics and post-fire effects

2006 ◽  
Vol 15 (3) ◽  
pp. 319 ◽  
Author(s):  
Leigh B. Lentile ◽  
Zachary A. Holden ◽  
Alistair M. S. Smith ◽  
Michael J. Falkowski ◽  
Andrew T. Hudak ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Fire Severity ◽  
Fire Behavior ◽  
Fire Effects ◽  
Ecological Effects ◽  
Fire Intensity ◽  
Active Fire ◽  
Post Fire Effects ◽  
Remote Sensing Techniques ◽  
Fire Characteristics

Space and airborne sensors have been used to map area burned, assess characteristics of active fires, and characterize post-fire ecological effects. Confusion about fire intensity, fire severity, burn severity, and related terms can result in the potential misuse of the inferred information by land managers and remote sensing practitioners who require unambiguous remote sensing products for fire management. The objective of the present paper is to provide a comprehensive review of current and potential remote sensing methods used to assess fire behavior and effects and ecological responses to fire. We clarify the terminology to facilitate development and interpretation of comprehensible and defensible remote sensing products, present the potential and limitations of a variety of approaches for remotely measuring active fires and their post-fire ecological effects, and discuss challenges and future directions of fire-related remote sensing research.

Soil carbon and nitrogen pools in mid- to late-successional forest stands of the northwestern United States: potential impact of fire

2006 ◽  
Vol 36 (9) ◽  
pp. 2270-2284 ◽  
Author(s):  
Deborah S Page-Dumroese ◽  
Martin F Jurgensen
Keyword(s):  
Soil Depth ◽  
Fire Suppression ◽  
Fire Severity ◽  
Mineral Soil ◽  
Soil Surface ◽  
Burned Area ◽  
Soil Productivity ◽  
N Losses ◽  
C And N ◽  
Surface Mineral

When sampling woody residue (WR) and organic matter (OM) present in forest floor, soil wood, and surface mineral soil (0–30 cm) in 14 mid- to late-successional stands across a wide variety of soil types and climatic regimes in the northwestern USA, we found that 44%–84% of carbon (C) was in WR and surface OM, whereas >80% of nitrogen (N) was in the mineral soil. In many northwestern forests fire suppression and natural changes in stand composition have increased the amounts of WR and soil OM susceptible to wildfire losses. Stands with high OM concentrations on the soil surface are at greater risk of losing large amounts of C and N after high-severity surface fires. Using the USDA Forest Service Regional Soil Quality Standards and Guidelines, we estimate that 6%–80% of the pooled C to a mineral-soil depth of 30 cm could be lost during a fire considered detrimental to soil productivity. These estimates will vary with local climatic regimes, fire severity across the burned area, the size and decay class of WR, and the distribution of OM in the surface organic and mineral soil. Estimated N losses due to fire were much lower (<1%–19%). Further studies on the amounts and distribution of OM in these stands are needed to assess wildfire risk, determine the impacts of different fire severities on WR and soil OM pools, and develop a link between C and N losses and stand productivity.

The effect of fire severity on ash, and plant and soil nutrient levels following experimental burning in a boreal mixedwood stand

1998 ◽  
Vol 78 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Mark Johnston ◽  
Julie Elliott
Keyword(s):  
Fuel Consumption ◽  
Forest Floor ◽  
Fire Ecology ◽  
Fire Severity ◽  
Mineral Soil ◽  
Rubus Idaeus ◽  
Nutrient Concentrations ◽  
Heat Output ◽  
Nutrient Inputs ◽  
Whole Tree

The Boreal Mixedwood Ecosystem Study near Thunder Bay, Ontario is a multi-disciplinary investigation of the impacts of harvesting and fire on the structure and function of a boreal mixed-wood ecosystem. The fire component comprises a set of treatments in which fire severity was manipulated by adjusting fuel loadings through a variety of harvesting techniques, and also included fire in standing timber. Intensive fuel sampling before and after the fire enabled detailed determinations of fuel consumption, heat output and forest floor reduction. Nutrient concentrations in ash, soil, and plant tissue following the fire were compared with fire severity in order to quantify potential nutrient inputs and their relationship to the amount of biomass consumed during the fire. Forest floor and woody fuel consumption varied significantly among treatments, with the most important factor being whether or not the stand had been harvested previous to the fire. The pH was highest and P concentrations among the lowest in the ash of unharvested blocks. Nutrient concentrations of the remaining forest floor and upper mineral soil were weakly related to the treatments. Forest floor P concentrations were highest on whole-tree harvested and lowest on uncut blocks. Whole-tree harvested blocks also had the highest pH values in forest floor and mineral soil. Concentrations of N, P, and Mg in the foliage of Populus tremuloides Michx. and Rubus idaeus L. were higher on unharvested burned than cut and burned plots, and were negatively correlated with the depth of forest floor reduction. These results indicate that fire severity plays a role in determining the extent of nutrient enrichment following fire, and may be important in influencing long-term site productivity. Key words: Fire severity, forest fire, nutrient cycles, soil chemistry, fire ecology

Determinants of riparian fire severity in two Oregon fires, USA

2008 ◽  
Vol 38 (7) ◽  
pp. 1959-1973 ◽  
Author(s):  
Jessica E. Halofsky ◽  
David E. Hibbs
Keyword(s):  
Random Sampling ◽  
Sampling Design ◽  
Fire Severity ◽  
Mineral Soil ◽  
Basal Area ◽  
Fire Effects ◽  
Forest Stand ◽  
Riparian Areas ◽  
Fuel Component ◽  
Crown Scorch

We sought to understand how vegetation indicators and local topographic factors interact to influence riparian fire severity in two recent fires in Oregon, USA. A stratified random sampling design was used to select points in a range of fire severity classes, forest stand ages, and stream sizes in each fire. At each point, plots were sampled in riparian areas and adjacent uplands. Fire severity was assessed in each plot, and measurements were made of factors that have been found to influence riparian fire severity. Understory fire severity (percent exposed mineral soil and bole char height) was significantly lower in riparian areas compared with adjacent uplands in both fires, suggesting a decoupling in understory fire effects in riparian areas versus uplands. However, overstory fire severity (percent crown scorch and percent basal area mortality) was similar in riparian areas and adjacent uplands in both fires. Fire severity in riparian areas was most strongly associated with upland fire severity. In addition, vegetation indicators, particularly those describing riparian fine fuel component and species composition, were strong predictors of riparian fire severity. Consistency in factors controlling fire severity in the two fires suggests that controls on riparian fire severity may be similar in other regions.

scholarly journals Wildfire and Prescribed Fire Effects on Forest Floor Properties and Erosion Potential in the Central Appalachian Region, USA

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 493
Author(s):  
Emma Georgia Thompson ◽  
Thomas Adam Coates ◽  
Wallace Michael Aust ◽  
Melissa A. Thomas-Van Gundy
Keyword(s):  
West Virginia ◽  
Prescribed Fire ◽  
Forest Floor ◽  
Fire Severity ◽  
Fire Intensity ◽  
National Forest ◽  
Appalachian Region ◽  
Litter Depth ◽  
Burned Forest

Short- and long-term impacts of wildland fires on forest floor properties and erosion potential were examined at three locations in the Central Appalachian region, U.S.A. In 2018, two wildfires were investigated within six months of burning on the George Washington–Jefferson National Forest (GWJNF) in Bland County, Virginia and the Monongahela National Forest (MNF) in Grant County, West Virginia. An additional wildfire was studied eight years post-fire on the Fishburn Forest (FF) in Montgomery County, Virginia. A 2018 prescribed fire was also studied within six months of burning on the MNF in Pendleton County, West Virginia. Litter and duff consumption were examined to evaluate fire severity and char heights were measured to better understand fire intensity. The Universal Soil Loss Equation for forestlands (USLE-Forest) was utilized to estimate potential erosion values. For the 2018 comparisons, litter depth was least as a result of the wildfires on both the MNF and GWJNF (p < 0.001). Wildfire burned duff depths in 2018 did not differ from unburned duff depths on either the MNF or GWJNF. Eight years after the FF wildfire, post-fire litter depth was less than that of an adjacent non-burned forest (p = 0.29) and duff depth was greater than that of an adjacent non-burned forest (p = 0.76). Mean GWJNF wildfire char heights were greatest of all disturbance regimes at 10.0 m, indicating high fire intensity, followed by the MNF wildfire and then the MNF prescribed fire. USLE-Forest potential erosion estimates were greatest on the MNF wildfire at 21.6 Mg soil ha−1 year−1 due to slope steepness. The next largest USLE-Forest value was 6.9 Mg soil ha−1 year−1 on the GWJNF wildfire. Both the prescribed fire and the 2010 wildfire USLE-Forest values were approximately 0.00 Mg soil ha−1 year−1. Implications for potential long-term soil erosion resulting from similar wildfires in Central Appalachian forests appeared to be minimal given the 2010 wildfire results.

Selected Parameters of Fire Behavior and Pinus banksiana Lamb. Regeneration in Eastern Ontario

1987 ◽  
Vol 63 (5) ◽  
pp. 340-346 ◽  
Author(s):  
M. G. Weber ◽  
C. E. Van Wagner ◽  
Monte Hummel
Keyword(s):  
Forest Floor ◽  
Pinus Banksiana ◽  
Tree Mortality ◽  
Mineral Soil ◽  
Fire Behavior ◽  
Jack Pine ◽  
Fire Intensity ◽  
Seedling Height ◽  
Ecological Requirements ◽  
Eastern Ontario

Fire behavior variables were quantified in eastern Ontario jack pine (Pinus banksiana Lamb.) ecosystems and used to interpret observed fire impacts and effects. A series of seven fires, ranging in frontal fire intensity from 70 to 17 000 W/m, were documented. Forest floor moisture content prior to burning was negatively correlated with weight of forest floor consumed per unit area (r2 = 0.97) and per cent mineral soil bared (r2 = 0.95). Frontal fire intensity was positively correlated with per cent tree mortality (r2 = 0.98) and mean height of char (r2 = 0.76). Frontal fire intensities of 17 000 kW/m resulted in seedling numbers of 30 000 to over 50 000 ha−1 considered to be more than adequate for establishing the next generation of crop trees. Jack pine mean seedling height, 13 to 16 years after fire, was also positively correlated with frontal fire intensity (r2 = 0.82), ranging from 0.5 to 3.8 m on lowest and highest intensity burns, respectively. Similar relationships were found when seedling height was regressed against per cent tree mortality (r2 = 0.62) and forest floor consumption (r2 = 0.79).Results are discussed in terms of ecological requirements of the species, particularly during the regeneration phase, and it is concluded that quantification of fire behavior observations is mandatory if burning conditions are to be understood and/or duplicated by the land manager for the attainment of a given forest management objective.

scholarly journals Emissions of forest floor and mineral soil carbon, nitrogen and mercury pools and relationships with fire severity for the Pagami Creek Fire in the Boreal Forest of northern Minnesota

2017 ◽  
Vol 26 (4) ◽  
pp. 296 ◽  
Author(s):  
Randall K. Kolka ◽  
Brian R. Sturtevant ◽  
Jessica R. Miesel ◽  
Aditya Singh ◽  
Peter T. Wolter ◽  
...  
Keyword(s):  
Forest Fires ◽  
Forest Floor ◽  
Infrared Imaging ◽  
Fire Severity ◽  
Mineral Soil ◽  
N Deposition ◽  
N2o Emissions ◽  
Natural Ecosystems ◽  
Imaging Spectrometer ◽  
Soil Level

Forest fires cause large emissions of C (carbon), N (nitrogen) and Hg (mercury) to the atmosphere and thus have important implications for global warming (e.g. via CO2 and N2O emissions), anthropogenic fertilisation of natural ecosystems (e.g. via N deposition), and bioaccumulation of harmful metals in aquatic and terrestrial systems (e.g. via Hg deposition). Research indicates that fires are becoming more severe over much of North America, thus increasing element emissions during fire. However, there has been little research relating forest floor and mineral soil losses of C, N and Hg to on-the-ground indices of fire severity that enable scaling up those losses for larger-scale accounting of fire-level emissions. We investigated the relationships between forest floor and mineral soil elemental pools across a range of soil-level fire severities following the 2011 Pagami Creek wildfire in northern Minnesota, USA. We were able to statistically differentiate losses of forest floor C, N and Hg among a five-class soil-level fire severity classification system. Regression relationships using soil fire severity class were able to predict remaining forest floor C, N and Hg pools with 82–96% confidence. We correlated National Aeronautics and Space Administration Airborne Visible and Infrared Imaging Spectrometer-Classic imagery to ground-based plot-scale estimates of soil fire severity to upscale emissions of C, N and Hg to the fire level. We estimate that 468 000 Mg C, 11 000 Mg of N and over 122 g of Hg were emitted from the forest floor during the burning of the 28 310 ha upland area of the Pagami Creek fire.

Seed banks of forested and disturbed soils in southwestern British Columbia

1993 ◽  
Vol 71 (12) ◽  
pp. 1574-1583 ◽  
Author(s):  
Ann McGee ◽  
M. C. Feller
Keyword(s):  
British Columbia ◽  
Seed Bank ◽  
Forest Floor ◽  
Vascular Plant ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Soil Surface ◽  
Seed Banks ◽  
Grass Species ◽  
Burial Depth

The species composition and density of seed banks in the forest floors and mineral soils of several undisturbed (immature, midseral forests) and disturbed (transmission line rights-of-way) ecosystems in southwestern British Columbia were estimated using the seedling-emergence method. The total soil surface area sampled was 9.4 m2. Germination behaviour of seven dominant species in response to depth of burial and substrate was also studied in a greenhouse experiment. A total of 16 289 seedlings germinated, representing 62 native and naturalized vascular plant species and several unidentified grass species. Most seedlings emerged from the forest floor, and the number of germinants generally decreased with increasing sample depth. Drier ecosystems had the lowest number and density of germinants. Burial depth significantly affected germination of all species tested. Mineral soil was equal, or superior, to forest floor as a germination substrate for all species tested. Depth–substrate interactions for several species indicated that the pattern of influence of burial depth in relation to substrate varied with species. Caution is urged extrapolating greenhouse seed-bank studies to potential weed populations in the field. Establishment of species from the seed bank will be a function of the depth to which the soil is disturbed and the kind of disturbance (burning, scarification) imposed. Key words: British Columbia, Coastal Western Hemlock zone, seed bank, seed germination, seed diversity, seed density.

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