Inferring changes in soil organic matter in post-wildfire soil burn severity levels in a temperate climate

Merino, Agustı́n; Fontúrbel, Teresa; Fernández, Cristina; Chávez‐Vergara, Bruno; García‐Oliva, Felipe; Vega, José A.

doi:10.1016/j.scitotenv.2018.01.189

Cited by 48 publications

(15 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A third potential fire responder trait is survival at elevated temperatures [93–94] (although increased temperatures from fire rapidly attenuate with soil depth [95]). In a study of tree bark-associated fungi in Australia, three Penicillium spp.…”

Section: Discussionmentioning

confidence: 99%

Soil Bacterial and Fungal Response to Wildfires in the Canadian Boreal Forest Across a Burn Severity Gradient

Whitman

Woolet

et al. 2019

Preprint

View full text Add to dashboard Cite

Global fire regimes are changing, with increases in wildfire frequency and severity expected for many North American forests over the next 100 years. Fires can result in dramatic changes to C stocks and can restructure plant and microbial communities, which can have long-lasting effects on ecosystem functions. We investigated wildfire effects on soil microbial communities (bacteria and fungi) in an extreme fire season in the northwestern Canadian boreal forest, using field surveys, remote sensing, and high-throughput amplicon sequencing. We found that fire occurrence, along with vegetation community, moisture regime, pH, total carbon, and soil texture are all significant predictors of soil microbial community composition. Communities become increasingly dissimilar with increasingly severe burns, and the burn severity index (an index of the fractional area of consumed organic soils and exposed mineral soils) best predicted total bacterial community composition, while burned/unburned was the best predictor for fungi. Globally abundant taxa were identified as significant positive fire responders, including the bacteria Massilia sp. (64x more abundant with fire) and Arthrobacter sp. (35x), and the fungi Penicillium sp. (22x) and Fusicladium sp. (12x) Bacterial and fungal co-occurrence network modules were characterized by fire responsiveness as well as pH and moisture regime. Building on the efforts of previous studies, our results identify specific fire-responsive microbial taxa and suggest that accounting for burn severity improves our understanding of their response to fires, with potentially important implications for ecosystem functions.

show abstract

Section: Discussionmentioning

confidence: 99%

Soil Bacterial and Fungal Response to Wildfires in the Canadian Boreal Forest Across a Burn Severity Gradient

Whitman

Woolet

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Given that the correlation between mass loss and the integral >300 • C was stronger (r = 0.48) than for time >300 • C (and significant), suggests that the faster rate of combustion associated with the process that generates higher temperature readings in thermocouples is more important in the overall mass loss process observed here than the total time during which mass loss occurs. This notion is supported by a study examining organic matter in a soil block affected by experimental laboratory burns, where the time >300 • C also showed no correlation with C loss (Merino et al, 2018).…”

Section: Mass Losses and Their Correlations With Temperature/durationmentioning

confidence: 93%

Fire as a Removal Mechanism of Pyrogenic Carbon From the Environment: Effects of Fire and Pyrogenic Carbon Characteristics

et al. 2018

Self Cite

View full text Add to dashboard Cite

Pyrogenic carbon (PyC, charcoal) is produced during vegetation fires at a rate of ∼116-385 Tg C yr −1 globally. It represents one of the most degradation-resistant organic carbon pools, but its long-term fate and the processes leading to its degradation remain subject of debate. A frequently highlighted potential loss mechanism of PyC is its consumption in subsequent fires. However, only three studies to date have tested this hypothesis with reported losses of <8-37%, with the effects of PyC chemical characteristics and fire conditions on PyC loss in wildfires remaining unexplored. To address this, we placed materials with different degrees of thermal and chemical recalcitrance (A: wildfire charcoal, B: slash-pile charcoal, C: pine wood and D: cedar wood) on the ground surface just prior to a high-intensity and a low-intensity boreal forest wildfire. Mass losses were highly variable and dependent on fire-and sample characteristics. Mass losses across both fires (as % of dry weight) were for A: 66.5 ± 25.2, B: 41.7 ± 27.2, C: 78.2 ± 14.9, and D: 83.8 ± 18.9. Mass loss correlated significantly with maximum temperature (T max ) recorded on sample surfaces (r = 0.65, p = 0.01), but only weakly (r = 0.33) with time >300 • C. Mass losses also showed a significant negative correlation (r = −0.38, p = 0.05) with thermal recalcitrance (T50) determined using Differential Scanning Calorimetry (DSC) and T max with charcoal reflectance (Ro) determined after the fires (r = 0.46, p = 0.05). Losses in the high-intensity fire were significantly higher (p = 0.05) than in the low-intensity fire, but the latter had a higher rate of conversion of fuel to PyC. Our results demonstrate that exposure to fire can indeed be a significant removal mechanism for PyC that remains exposed on the ground after a previous fire. The losses found, however, are likely to represent an extreme upper range as most PyC produced in a fire would not remain exposed on the ground surface by the time the next fire occurs. Our data also demonstrate, for real wildfire conditions, the (i) contrasting resistance of different PyC types to combustion and (ii) contrasting net PyC losses between different fire intensities. The DSC and reflectance (Ro) results support the usefulness of these analyses in reflecting thermal degradation resistance and temperature exposure under actual wildfire conditions.

show abstract

“…It is therefore necessary to study the relationships between burn severity and changes in soil status and processes in different types of ecosystems and especially in those prone to fire. A better understanding of the impact of burn severity on ecosystems may help to clarify its value as a tool to identify target areas in which to implement emergency stabilisation strategies (Merino et al 2018). Some studies have analysed changes in soils related to burn severity (Jordán et al 2011;Jain et al 2012;Pingree et al 2012;Dzwonko et al 2015;Miesel et al 2015;Moody et al 2016), but few analyse the effects of burn severity on soil properties immediately after a wildfire (Vega et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Impact of burn severity on soil properties in a Pinus pinaster ecosystem immediately after fire

Fernández-García

Marcos

Fernández‐Guisuraga

et al. 2019

Int. J. Wildland Fire

View full text Add to dashboard Cite

We analyse the effects of burn severity on individual soil properties and soil quotients in Mediterranean fire-prone pine forests immediately after a wildfire. Burn severity was measured in the field through the substrate stratum of the Composite Burn Index and soil samples were taken 7–9 days after a wildfire occurred in a Pinus pinaster Ait. ecosystem. In each soil sample, we analysed physical (size of soil aggregates), chemical (pH, organic C, total N and available P) and biological (microbial biomass C, β-glucosidase, urease and acid phosphatase activities) properties. Size of aggregates decreased in the areas affected by high burn severity. Additionally, moderate and high severities were associated with increases in pH and available P concentration and with decreases in organic C concentration. Microbial biomass C showed similar patterns to organic C along the burn severity gradient. The enzymatic activities of phosphatase and β-glucosidase showed the highest sensitivity to burn severity, as they strongly decreased from the low-severity scenarios. Among the studied soil quotients, the C:N ratio, microbial quotient and β-glucosidase:microbial biomass C quotient decreased with burn severity. This work provides valuable information on the impact of burn severity on the functioning of sandy siliceous soils in fire-prone pine ecosystems.

show abstract

Inferring changes in soil organic matter in post-wildfire soil burn severity levels in a temperate climate

Cited by 48 publications

References 60 publications

Soil Bacterial and Fungal Response to Wildfires in the Canadian Boreal Forest Across a Burn Severity Gradient

Soil Bacterial and Fungal Response to Wildfires in the Canadian Boreal Forest Across a Burn Severity Gradient

Fire as a Removal Mechanism of Pyrogenic Carbon From the Environment: Effects of Fire and Pyrogenic Carbon Characteristics

Impact of burn severity on soil properties in a Pinus pinaster ecosystem immediately after fire

Contact Info

Product

Resources

About