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SSS9.10

According to the Global Wildfire Information System, every year approximately 350 million hectares of land are affected by wildfires. This global phenomenon is responsible for substantial environmental, social and economic losses, which together with land abandonment, droughts, absence of appropriate land management and urban development planning, are expected to aggravate land degradation. In addition, wildfires are becoming a persistent threat, since the fire risk is expected to increase in a context of a warmer and drier climate.
This increased land degradation as a consequence of wildfires has also been highlighted in the latest Climate Change and Land, IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. The impacts of wildfires on soils and ecosystems severely affect ecosystem services supply such as raw material and water provisioning, carbon storage, erosion and flood control, and habitat support, which are essential for human life. Therefore, attention of researchers, stakeholders and decision makers worldwide is urgently needed.
The aim of this session is to join researchers that study the effects of wildfires on ecosystems from wildfire prevention to post-fire mitigation. We warmly invite studies that approach:
i. prescribed and/or experimental fires;
ii. fire severity and burn severity;
iii. fire effects on vegetation, soils and water;
iv. post-fire hydrological and erosive response;
v. post-fire management and mitigation;
either by means of laboratory, field experiments, and/or numerical modelling.

Public information:
Short summary and feedback of the session
Our session aimed at bringing together researchers who study the effects of wildfires on ecosystems from wildfire prevention to post-fire mitigation. Overall, all the objectives of the session were addressed, and the main outcomes from this session agree in the need for a multidisciplinary approach to implement adequate pre-and post-fire management. It should be highlighted that many advances are being made:
• at the level of using remote-sense technologies to address wildfire risk and fuel connectivity within rural-urban interfaces;
• in the development of direct and indirect techniques to determine/estimate impacts of fires in soil properties;
• more than in the past, we can now observe more studies addressing post-fire mitigation treatments;
• the same way, several advances were made in modeling post-fire hydrological response and soil erosion processes.

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Co-organized by GM4/NH7
Convener: Diana VieiraECSECS | Co-conveners: Jantiene BaartmanECSECS, Marcos FrancosECSECS, Antonio Girona-GarcíaECSECS, Paulo Pereira
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| Wed, 06 May, 16:15–18:00 (CEST)

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Chat time: Wednesday, 6 May 2020, 16:15–18:00

Chairperson: Diana Vieira
D2115 |
EGU2020-13770
Angelica Feurdean, Andrei Cosmin Diaconu, Gabriela Florescu, Mariusz Galka, Simon M. Hutchinson, Mirjam Pfeiffer, Sergey Kirpotin, Ioan Tanţău, and Boris Vannière

Although wildfire events in Siberia have increased in frequency and intensity over recent decades, in the absence of long-term records, it is not clear how far this trend deviates from baseline conditions. Short-term datasets categorise the forest fire regime in Siberia as one of surface, litter fires alternating withdevastating crown fires, although there is significant variability within this region likely reflecting vegetation composition. However, a comprehensive understanding of how vegetation composition and properties determine fire regimes remains lacking. To address this question we used two peat records spanning the last 2500 yr and a 5000 yr, respectively of charcoal morphologies-derived fire regime, pollen-based vegetation dynamics and stable isotope and testate amoebae-based climate reconstructions from boreal forests in central western Siberia, combined with fire-related functional traits of key boreal tree species. Compared to the trend over the 5000 yr period (mean fire return interval=FRI of 400 yr), our reconstructed mean FRI of 145 yr for the last five centuries is notably the shortest in the record. Most fires in this area tend to be surface, litter fires, although over the last centuries surface fires show an increased trend towards crowning. Frequent fires between 5000 and 4000 cal yr BP and 1500 cal yr BP to the present were concurrent with the dominance of invader species (primarily Betula) and fire endurer (mainly herbs) with prevalence of resisters (Pinus sylvestris, Pinus sibirica). Longer fire return intervals (up to 500 yr) between 4000 and 1500 cal yr BP were associated with the dominance of fire resisters with a considerable proportion of fire avoiders (Abies sibirica and Picea obovata). The rising number of fire episodes and the intensification of fire events over the past 1500 years have likely promoted fire-adapted plant communities (invaders and endurers) that can rapidly reach maturity, contributing to the reduction of avoider and resister species. This trend demonstrates that fire avoider species particularly fail to regenerate if the intervals between fire episodes are too short and thatan increasing number of fire episodes can drive land cover towards more fire-adapted plant communities. Our long-term perspective shows that the current fire regime lies significantly outside baseline conditions, which may drive future change in forest composition towards an increased prevalence of invader species. This study also contributes to an understanding of disturbance regimes in Pinus-Betula forests and considers the potential of tree species to adapt to new fire regimes.

 

How to cite: Feurdean, A., Diaconu, A. C., Florescu, G., Galka, M., Hutchinson, S. M., Pfeiffer, M., Kirpotin, S., Tanţău, I., and Vannière, B.: Recent fire activity in the boreal forests of central western Siberia is unprecedented in the past 5000 years: palaeoenvironmental evidence contextualises a burning issue , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13770, https://doi.org/10.5194/egusphere-egu2020-13770, 2020

D2116 |
EGU2020-974
Iva Hrelja, Ivana Šestak, Aleksandra Perčin, Paulo Pereira, and Igor Bogunović

Fire is an important element of the ecosystems, nevertheless, high severity fires can have negative impacts on the ecosystems as consequence of the high temperatures reaches. High temperatures normally have detrimental impacts on soil properties. The objective of this work was to determine the relationship of spectral reflectance and soil pH, electrical conductivity (EC), carbonates (CaCO3) and total carbon (TC) content after a medium to high severity wildfire occurred in Croatia using linear and nonlinear calibration models.

Soils were sampled 2 days after a medium to high severity wildfire in Zadar County, Croatia. A total of 120 soil samples (0-5 cm) were collected from three different treatments (n= 40 per treatment): control (C), mean severity (MS), high severity (HS). Soil pH, EC, CaCO3 and TC content were determined using standard laboratory methods.  Soil spectral measurements were carried out using a portable spectroradiometer (20 per treatment, 60 in total). Linear statistical model - partial least squares regression (PLSR) and non-linear - artificial neural network (ANN) were generated to estimate changes in soil pH, EC, CaCO3 and TC content based on the original spectral reflectance and its first derivative in form of principal components (PC). One-way ANOVA revealed pH values were significantly different in all three treatments. EC, CaCO3 and TC were significantly higher in HS plots compared with the other treatments.

Different wildfire severity indicated very collinear soil spectral response, but with certain variations of reflectance intensity. Control samples showed a higher reflectance than MS and HS samples. This is attributed to the low pH and TC content. Low reflectance of MS and HS samples could be explained by their increased pH and TC values. Soil pH was the only parameter that showed a high R2 and low root mean squared error (RMSE) after Savitzky Golay smoothing and the first derivation. In PLSR model, strong to very strong correlation and low RMSE were obtained. ANN model also showed a high R2 and lower RMSE for all properties except pH. Both models showed satisfactory results for prediction of the studied soil properties. ANN model predicted EC, CaCO3, and TC better, while PLSR proved to be a better model for pH prediction.

Key words: soil reflectance, fire severity, principal components, partial least squares regression, neural networks

Acknowledgements

This work was supported by Croatian Science Foundation through the project "Soil erosion and degradation in Croatia" (UIP-2017-05-7834) (SEDCRO).

How to cite: Hrelja, I., Šestak, I., Perčin, A., Pereira, P., and Bogunović, I.: VNIR spectroscopy for assessment of post-fire impacts on soil properties using linear and non-linear calibration methods, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-974, https://doi.org/10.5194/egusphere-egu2020-974, 2019

D2117 |
EGU2020-10672
Cristina Santin, Agustin Merino, Parvaneh Sayyad-Amin, and Stefan H. Doerr

In this presentation, we will assess the direct impacts of a prescribed fire on the quantity and composition of organic matter in oligotrophic soils of a dry eucalypt forest (Warragamba, Sydney, Australia). Samples of the litter layer and surface soils horizons (Oa and Ah) were collected immediately before and after the fire. The prescribed fire was carried out September 2014 and was classified of moderate to high severity. In addition to litter and soil, samples of ash (burnt litter) were also collected after the fire.  In order to monitor the temperatures reached by the different soil organic matter pools during the fire, we installed thermologgers at the litter layer (n=30), the surface of the Oa soil horizon (n = 9), and at 1 cm depth within the Ah soil horizon (n =4). All samples were characterized by elemental analysis (total carbon, nitrogen, oxygen and hydrogen), thermogravimetry-differential scanning calorimetry and, a selected subset by solid-state 13C nuclear magnetic resonance. The observed changes in quantity and characteristics of the different organic matter pools will be discussed and the relationships between these changes and the temperatures recorded during the burn explored.

How to cite: Santin, C., Merino, A., Sayyad-Amin, P., and Doerr, S. H.: Impacts on soil organic matter quantity and composition of a prescribed fire in a eucalypt forest (Sydney, Australia) , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10672, https://doi.org/10.5194/egusphere-egu2020-10672, 2020

D2118 |
EGU2020-5765
Severin-Luca Bellè, Asmeret Asefaw Berhe, Frank Hagedorn, Marcus Schiedung, and Samuel Abiven

Wildfires are a key component in the global carbon (C) cycle, releasing significant amount of CO2 to the atmosphere, but also producing one of the most persistent terrestrial organic C forms by the incomplete combustion of natural vegetation, namely fire-derived or pyrogenic carbon (PyC). Post-fire, PyC is deposited on the soil surface, but can then be laterally redistributed by wind or water erosion. Due to the lack of vegetation cover after a fire, primary factors that govern rate of PyC distribution post-fire will be changes in soil surface properties and physical characteristics of PyC. However, the drivers and quantities of transported PyC (and non-fire derived organic matter) by water erosion from its site of production remain largely unknown, which limits our understanding of PyC movement in the landscape.

In this study, we tracked PyC erosion (and movement in soil) in a controlled experiment using a gravity-type rainfall simulator (at an intensity of 50mmh-1). We studied the quantity of PyC eroded from the soil surface (runoff and splash sediment) as well as its vertical movement within the soil (soil cores) for two Swiss temperate forest soils (initial soil moisture of 12-16%). We calculated the distribution of PyC using the isotopic 13C signature differences of grass-PyC (Miscanthus grass), wood-PyC (spruce wood grown under FACE conditions) and natural forest soil C in soil flume of 0.25m2. We studied the combination of the following factors: soil texture (sandy silt and clay loam), slope (10° and 25°), PyC particle size (63µm and 63µm-2mm) and PyC feedstock (grass and wood) to identify the major drivers of PyC redistribution.

We hypothesize that: i) higher quantities of PyC can be found in the sediment of the sandy silt soil, with higher slopes and with bigger PyC particles, ii) higher quantities of PyC move vertically in the clay loam soil and with smaller PyC particles and iii) PyC is preferentially eroded compared to bulk SOC.

Results suggest that we find 100 times more runoff sediment on sandy silt soil compared to clay loam soil, and two times more runoff sediment on 25° slope compared to 10°. We also find 1.5 times more splash erosion on sandy silt soil than on the clay loam soil. Regarding PyC erosion, observations suggest that > 50% of initial PyC is eroded on the sandy silt soil, whereas a majority of the PyC particles moves vertically through the soil for the clay loam.

How to cite: Bellè, S.-L., Asefaw Berhe, A., Hagedorn, F., Schiedung, M., and Abiven, S.: Lateral redistribution of fire-derived carbon: A rainfall simulation experiment , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5765, https://doi.org/10.5194/egusphere-egu2020-5765, 2020

D2119 |
EGU2020-19102
| Highlight
Dalila Serpa, Ana I. Machado, Martha Santos, Isabel Campos, Bruna R. F. Oliveira, Behrouz Gholamahmadi, Martinho Martins, Oscar González-Pelayo, Fátima Jesus, Jacob Keizer, Nelson Abrantes, and Life-Reforest Consortium

Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt areas, the increase in surface runoff and associated sediment losses after fire, promotes the mobilization of hazardous substances, such as metals and polycyclic aromatic hydrocarbons (PAHs), posing a risk for the adjacent water bodies. In the present study, post-fire metals and PAHs export by surface runoff was evaluated in 16 m2 bounded plots in a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) burnt in September 2019. Runoff samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rainfall, during the first 6 months after fire. The metals analyzed in this study were, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). As for PAHs, the analyses focused on the 16 compounds classified as priority pollutants by the United States Environmental Protection Agency. Both dissolved and particulate fractions of metals and PAHs in runoff waters were analysed in this work. Preliminary results suggest that metals are more likely to affect the water quality of fire-affected water bodies than PAHs, since low levels of PAHs were found in runoff waters. This work provides valuable information for water managers to minimize the risks of wildfires both to the environment and to public health.

How to cite: Serpa, D., I. Machado, A., Santos, M., Campos, I., R. F. Oliveira, B., Gholamahmadi, B., Martins, M., González-Pelayo, O., Jesus, F., Keizer, J., Abrantes, N., and Consortium, L.-R.: Post-fire mobilization of metals and polycyclic aromatic hydrocarbons in a recently burnt eucalypt stand in North-Central Portugal, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19102, https://doi.org/10.5194/egusphere-egu2020-19102, 2020

D2120 |
EGU2020-22181
Ian Floyd, Stanford Gibson, Gaurav Savant, Alejandro Sanchez, and Ronald Heath

The number and intensity of large wildfires in is a growing concern in the United States.  Over the past decade, the National Interagency Fire Centre (NSTC, 2015) reported increases of large fires in every western state in the arid and semi-arid western U.S.  Wildfires, remove vegetation, reduce organic soil horizons to ash, extirpate microbial communities, alters soil structure, and potential development of hydrophobic soils.  These processes all increase water and sediment runoff. Post-wildfire environments can cause a spectrum of hydrologic and sedimentation responses ranging from no response to catastrophic floods and deadly debris flows. Numerical modellers have developed a variety of Newtonian and non-Newtonian shallow-water algorithms to simulate each of these physical processes – making it difficult to model the range of post-wildfire flood conditions and understand model assumption and limitations. This makes a modular non-Newtonian computation library advantageous. This work presents a flexible, numerical model, library framework ‘DebrisLib’ to simulate large-scale, post-wildfire non-Newtonian flows using diverse shallow-water parents code architecture. This work presents the non-Newtonian model framework effectiveness by linking it with two different modelling frameworks, specifically the diffusive-wave one-dimensional and two-dimensional Hydrologic Engineering Center River Analysis System (HEC-RAS), and shallow-water two-dimensional Adaptive Hydraulics (AdH) numerical models. The model library was verified and validated using three flume experiments for mud flows, hyperconcentrated flows, and debris flows under steady and unsteady flow conditions. Additionally the shallow-water model library framework linked with the 1D Hydrologic Engineering Centre Hydrologic Modelling System (HEC-HMS) successfully predicted the 2018 post-wildfire flooding and debris flows following the 2017 Thomas Fire near Santa Barbara, California.

How to cite: Floyd, I., Gibson, S., Savant, G., Sanchez, A., and Heath, R.: Post-Wildfire Numerical Modeling for Flood Risk Management, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22181, https://doi.org/10.5194/egusphere-egu2020-22181, 2020

D2121 |
EGU2020-3384
Manuel Esteban Lucas-Borja, Cristina Fernández, Pedro Antonio Plaza- Alvárez, Javier González-Romero, Esther Peña-Mollina, Daniel Moya, and Jorge De las Heras

Mulching application and salvage logging are often performed in forests after fire to recover timber values and avoid soil erosion. These post-fire practices are believed to positively and negatively impact soil properties and initial seedling recruitment or seedling growth in pine stands. Mulch may increase soil moisture and lower soil temperature, which thus promotes seedling recruitment, whereas logging operations may generate soil compaction and destroy seedlings. As Mediterranean forests are delicate ecosystems, and different pine species or contrasting microclimate conditions (semiarid vs. subhumid Mediterranean climates) can display several natural regeneration trends, we investigated whether mulching combined with logging significantly alters soil properties, initial seedling recruitment and seedling growth in burned Pinus halepensis (Lietor) and Pinus pinaster (A Gudiña) stands in the short term. Our results demonstrated that soil organic matter and total nitrogen were the only soil parameters affected by treatments at site Liétor. Monitoring activity confirmed that regardless of tree felling or not, mulch treatment improved seedling density in the short term with a semiarid Mediterranean climate. At Liétor, seedling density was over 40% higher when mulching was applied, whereas aerial seedling length was the only seedling variable affected by this treatment. Conversely, the mulching+logging combination showed the highest seedling density, which could be related with more light availability after tree felling and the almost null effect of employed logging machinery. The harsh conditions at Liétor due to the limited water and light demands of pine species when water resources were ensured at site A Gudiña could be decisive for understanding the effect of mulching and logging operations for initial seedling recruitment. Our results generally suggest short-term soil changes and contrasting initial seedling recruitments after mulch and logging in burned semiarid and subhumid Mediterranean pine forests. 

 

How to cite: Lucas-Borja, M. E., Fernández, C., Plaza- Alvárez, P. A., González-Romero, J., Peña-Mollina, E., Moya, D., and De las Heras, J.: Do alter post-wildfire straw mulching application and salvage logging pine natural regeneration after wildfires? , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3384, https://doi.org/10.5194/egusphere-egu2020-3384, 2020

D2122 |
EGU2020-1200
Maria Polinova, Haim Kutiel, Lea Wittenberg, and Anna Brook

Climate change, increased frequency of natural disasters and their anomaly in the modern world demand review existing knowledge about environment and approaches for its management. In recent decades, one of the phenomena that humanity met with is urban wildfires. Experience has shown that existing approaches from forest fire management are not effective in a built-up environment. In practice, studying this phenomenon is limited due to lack of empirical knowledge.

To bridge this knowledge gap, the fire dynamic patterns in an urban area was reconstructed based on fire service data on the example of wildfire in Haifa (Israel) in November 2016. The results of reconstruction show that unlike forest fires, where fuel is almost unlimited around the ignition point, urban areas are sensitive to wildfire because of 'fire connectivity' through vegetation: fire moves from one green patch to another, bypassing nonflammable structures.

Although the role of urban vegetation in the spread of fires is obvious, it is difficult to define a suitable term in case of fire management. Today, cities and vegetation are studied together in the urban planning and ecosystem services and have different definitions, depends on study propose: ‘Urban Green Spaces’, ‘Green Infrastructure’, ‘Urban Forestry’, etc. The closest term in fire management for vegetation interaction with structures is ‘Wildland Urban Interface’ (WUI). However, WUI considers vegetation surrounding the city and excludes urban green spaces. Since before this time the inner-city vegetation was not considered in the fire management and wasn’t estimated its essential parameters for this case, it does not have an exact term and definition. The reconstructed wildfire allows to analyze and define vegetation in context of fire connectivity.

The results show that wildfire spreads in the urban area through ember attacks. Meanwhile, the embers led to ignition only in some patches and only in a few cases the energy amount was enough for new embers emission. Thus, the fire vegetation connectivity in urban areas can be defined by its ability to ignite and reproduce new embers.

To support fire management and risk assessment in urban areas, it is important to map vegetation based on its ignitability and potential energy emission. The task is complicated due to the uncertainty of surface fuel (including both litter and human waste). Citywide, detecting and monitoring such patches through field surveys is time-consuming work. To solve this objective by remote sensing technique, we analyzed series of Landsat 8 images for 2015 to identify spectral and temporal features of vegetation related to its flammability. The proposed approach supports estimation and mapping of vegetation connectivity in case of urban wildfire based on its multi-temporal spectral signature.

How to cite: Polinova, M., Kutiel, H., Wittenberg, L., and Brook, A.: Wildfire spreading across the urban area: definition and mapping of vegetation connectivity, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1200, https://doi.org/10.5194/egusphere-egu2020-1200, 2019

D2123 |
EGU2020-5088
Jingyu Zhao, Jun Deng, Furu Kang, and JiaJia Song

Jurassic coal samples from two coal mines were selected for oxidative thermal energy experiments. By using a temperature-programmed experimental system, the variation of gaseous products was obtained, and the changes in thermal energy release with temperature were measured. Thermokinetic parameters, such as apparent activation energy (Ea) and pre-exponential factor (A), of the coal samples under four different heating rates, were determined by thermogravimetric analyzer. The results showed that during the low-temperature oxidation stage, the index gas (CO) used to characterize the spontaneous combustion state of the coal body was roughly the same as the temperature curve of the two samples with the temperature change, but the critical temperature was different. The WD sample produced less CO gas. However, the maximum and minimum exothermic strengths of the two samples showed similar to temperature change curves. The characteristic temperatures for coal were discovered using different heating rates. For the WD sample, the characteristic temperature varied according to the heating rate. For the same type of sample, the TG and DTG curves lagged with an increase in heating rate. Characteristic temperatures T1−T5 had an increasing tendency with an increase in heating rate. As one of the integral methods, Coats-Redfern integral method was adopted to capture the thermokinetic parameters of the samples. The straight line fitting by this method was higher. The heating rate conditions increased from 2 to 15 °C min-1 when the oxygen concentration was 21 vol%, the apparent activation energy of the samples decreased with an increase in the heating rate.

How to cite: Zhao, J., Deng, J., Kang, F., and Song, J.: Thermokinetic characteristics of coal spontaneous combustion of Jurassic coal from China, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5088, https://doi.org/10.5194/egusphere-egu2020-5088, 2020

D2124 |
EGU2020-8904
JiaJia Song, Jun Deng, and JingYu Zhao

Coal spontaneous combustion is one of the severe nature hazards among nature resources. There are many influence factors which control the development of spontaneous combustion such as particle size, oxygen concentration, etc. Weathering effects alter the spontaneous combustion characteristics of coal. To explore the effect of particle size on gas emission from weathered coal under high temperature oxygen deficiency, the macroscopic spontaneous combustion characteristics of weathered coal with various particle sizes in high temperature oxidation process were studied. The gas concentration of different particle sizes with weathered coal oxidation from normal temperature to 600 °C was tested by the self-built high temperature program experiment system, and the variation law of the indicator gas was analyzed. The results showed that there were different experimental phenomena in each particle size coal sample. The concentration of indicator gas neither increased nor decreased monotonically with the change of particle size. Roughly, 3 mm is the critical particle size in the process of high temperature oxidation of weathered coal. The experimental results provided a pivotal theoretical basis for the early prediction and the scientific prevention of the spontaneous combustion of the weathered coal during the mining process of the open pit and the shallow coal seam.

How to cite: Song, J., Deng, J., and Zhao, J.: Effect of particle size on indicator gas emission during high-temperature oxidation of weathered coal, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8904, https://doi.org/10.5194/egusphere-egu2020-8904, 2020

D2125 |
EGU2020-11536
Anna Losiak, Amber Avery, Andy Elliott, Sarah Baker, and Claire Belcher

     Properties of the wildfires are hard to precisely and accurately measure during the event. This limits our ability to estimate effects of the event on the environment (e.g., how quickly will the area be able to recover, and what will be the long-term carbon storage in an ecosystem Hurteau and Brooks, 2011). Currently used methods of estimating of the ‘fire severity’ (the amount of vegetation and carbon loss from an ecosystem following a fire) are either subjective (fire severity scales Ryan and Noste 1985), time consuming (charcoal reflectance Belcher et al. 2019) or expensive (thermocouples with data-loggers).

     Here we present results of our proof of concept tests of a new approach that may allow ecologists to monitor fire severity and the energy distribution across a burned area by looking at the effects of the fire on litter such as tin cans, bottles and plastic items, that are often revealed following wildfire events. The approach is based on the fact that different types of packages and materials are known to decompose at different temperatures. We will present results from: 1) Field observations of burned litter compared with the charcoal reflectance measurements based on samples collected in the same spot from the 2018 Ferndown, UK. 2) experimental heating of a range of typical litter based elements in the wildFIRE Lab, using it’s state-of-the-art fire testing equipment; 3) results of the field-scale experiments performed during the controlled burns in Dorset in the beginning of 2020.

How to cite: Losiak, A., Avery, A., Elliott, A., Baker, S., and Belcher, C.: Burning trash for science - using waste to monitor wildfire energies, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11536, https://doi.org/10.5194/egusphere-egu2020-11536, 2020

D2126 |
EGU2020-512
Marek Tuhý, Vojtěch Ettler, Jan Rohovec, Šárka Matoušková, Martin Mihaljevič, Juraj Majzlan, Bohdan Kříbek, and Ben Mapani

Wildfires contribute to global emissions of trace elements. This study focuses on highly polluted areas near an operating copper smelter and old mine-tailing disposal sites in Tsumeb (semi-arid north of Namibia), where wildfires frequently occur. Capturing of particulates windblown from the ore processing and smelting areas by vegetation (trees, grass) leads to the topsoil enrichment with metal(loid) contaminants (up to 7090 mg/kg Cu, 2070 mg/kg As, 4820 mg/kg Pb, 3480 mg/kg Zn, 75 mg/kg Cd, 7.66 mg/kg Hg). Experimental samples corresponding to representative biomass-rich topsoils (bushland with acacia and marula trees, grassland) were investigated using a combination of mineralogical and geochemical methods. Wildfires were simulated using a thermodesorption (TD) technique (75-670 °C; Hg) and an experimental setup composed of a temperature-controlled furnace (250-850 °C), an aerosol-filtering unit and a gas-trapping device (As, Cd, Cu, Pb, Zn). The obtained ashes were investigated to depict any mineralogical and chemical transformations in order to understand temperature-dependent release of metal(loid) contaminants during the simulated wildfire.

Thermodesorption experiments indicated that more than 90% of Hg was released at ~340 °C, which corresponded to predominant grassland-fire conditions. A comparison with the TD curves of the Hg reference compounds confirmed that the Hg in the biomass-rich topsoils occurs as a mixture of Hg bound to the organic matter and metacinnabar (black HgS), which exhibited similarities with the TD pattern of smelter flue dust residue. Temperature-dependent release of other metal(loid)s (As, Cd, Cu, Pb, Zn) is dependent on their solid-state speciation. Cadmium is released at ~750 °C, corresponding to the thermal decomposition of carbonates, in which Cd is mainly bound. Arsenic exhibits first remobilization step at <350 °C (decomposition of arsenolite, As2O3) and the second step at >650 °C corresponding to the instability of arsenates and As-rich slag glass. Other contaminants (Cu, Pb, Zn) were mainly bound in carbonates, slag particles and sulfides/sulfosalts. During the simulated wildfire, they were mainly retained in the ash and were remobilized to a lesser degree at >650 °C. Calculations indicated that at 850 °C (worse-case wildfire scenario) 2-17 % of total As, Cu, Pb and Zn, 27-79 % of total Cd and 100 % of Hg can be volatilized from these biomass-rich contaminated topsoils.

This study was supported by the Czech Science Foundation (GACR project no. 19-18513S) and a student grant from the Grant Agency of Charles University (GAUK no. 1598218).

How to cite: Tuhý, M., Ettler, V., Rohovec, J., Matoušková, Š., Mihaljevič, M., Majzlan, J., Kříbek, B., and Mapani, B.: Wildfire-driven release of metal(loid)s from topsoils in a smelter-polluted semi-arid area: an experimental approach, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-512, https://doi.org/10.5194/egusphere-egu2020-512, 2019

D2127 |
EGU2020-12513
Sebastián A. Aedo and Carlos A. Bonilla

High temperatures reached at topsoil during wildfires can induce changes in physical, chemical, and biological soil properties. In the end, these changes are related to the loss of soil organic matter (SOM) and control the post-fire soil management decision. Therefore, the objectives of this study were: (1) to develop a numerical model to predict the SOM decay during wildfires, and (2) to study which are the main parameters that control the soil response. The model couples the energy balance for soil heating, and the species conservation for water and SOM using high temperature-induced vaporization and combustion kinetics. Fluid flow was neglected; however, radiative energy conducted through pores was included as a function of the volumetric pore radius. The soil thermal evolution showed values of r2>0.92 when the radiative term in the thermal conductivity was neglected, and r2>0.98 when the volumetric pore radius was adjusted. The results showed that the main parameters that control the soil response were soil texture, soil water content, volumetric pore radius, and oxygen availability. Also, soil response depends on the surface temperature and exposure time. Soil water content enhances the thermal properties and determines the amount of heat consumed during vaporization because of the high enthalpy of this endothermic reaction. On the other hand, neglecting oxygen flux leads to restricted oxidation, limiting the SOM decay. In terms of texture, silty soils showed the lower soil response, clay and loamy soils an intermediate response, and sandy soils had a higher response. Also, the volumetric pore radius enhances the soil thermal conductivity at high temperatures, leading to higher temperatures near the soil surface. These results suggest that the normalized SOM decay does not depend on the initial SOM content.

How to cite: Aedo, S. A. and Bonilla, C. A.: A numerical approach for understanding the main parameters and processes influencing the soil organic matter decay in wildfire events, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12513, https://doi.org/10.5194/egusphere-egu2020-12513, 2020

D2128 |
EGU2020-12365
Sofía Martínez, Cristina Contreras, Sara Acevedo, and Carlos Bonilla

Wildfires affect soil physical, chemical, and hydraulic properties, which in turn control many processes such as soil water availability, soil water balance, infiltration, and soil stability. Because of the multiple factors controlling the changes in soil properties and the nature of fire events, the number of predictive models for these effects is limited. Therefore, the objective of this study was to develop a soil-burning laboratory procedure to identify changes in physical and hydraulic soil properties across a fire temperature range. With this purpose, saturated hydraulic conductivity, pH, electric conductivity, soil texture, aggregate stability, repellency, and organic matter content (OM) were measured in soils burned at increasing temperatures. Six sandy loam soils were burned at four different temperatures (300ºC, 500ºC, 700ºC and 900ºC) and non-burned samples were used as a control to compute the change on each property. Additionally, three of these soils were sampled in a naturally burned area and used later to test the laboratory setup reliability to reproduce a natural fire. Preliminary results for soils burned in a muffle furnace (300ºC for two hours) showed that the changes in physical properties are more significant with soils rich in OM. On the other hand, properties such as water retention and hydraulic conductivity curves showed little variation at 300ºC.

How to cite: Martínez, S., Contreras, C., Acevedo, S., and Bonilla, C.: Wildfire temperature effect on soils physical and hydraulic properties, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12365, https://doi.org/10.5194/egusphere-egu2020-12365, 2020

D2129 |
EGU2020-6600
Marcus Schiedung, Severin-Luca Bellè, Alysha Coppola, and Samuel Abiven

Wildfires produce a fire-derived carbon (C) residue known as pyrogenic carbon (PyC). This residue is one of the largest and most persistent terrestrial organic C pools with residence times over 1000 years. Large quantities of PyC can remain on the site where the fire occurs or can be transferred along the landscape and eventually enter the soil where it represents a major component of the total soil organic carbon (SOC). The drivers explaining the vertical PyC mobility in soils and the quantities it represents remain largely unknown, which limits our understanding of the fate of PyC in the terrestrial systems. Here, we used a manipulative soil column experimental approach in order to study the proportion of transportable PyC and its interaction with the soil mineral phase and non-fire-derived SOC during its vertical transport. To do this, we applied highly 13C-labelled ryegrass biochar (as a PyC proxy) on the upper layer of small soil columns (7 cm length, 2.5 cm diameter), and traced the fire-derived C in the soil and in the soluble fractions sequentially extracted during a percolation of 600 pore volumes under saturated conditions (equivalent to 18 years continues rainfall). We studied a combination of ranging soil texture (sandy loam and sand), SOC content (0.3-3.0%) and weathering state (age) of the ryegrass biochar (artificial oxidation with H2O2) to identify drivers controlling the vertical mobility of fire-derived C. We hypothesized that: i) Significant proportions of fire-derived C are transported through the soil column over the whole experimental period but decrease with time, ii) fire-derived C can be retained and stabilized within the soil column and influence the mobility of non-fire-derived SOC and iii) weathered fire-derived C is more mobile than fresh fire-derived C which may control its long-term fate in soils.

How to cite: Schiedung, M., Bellè, S.-L., Coppola, A., and Abiven, S.: How much fire-derived carbon is transported vertically through the soil and what controls its mobility? , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6600, https://doi.org/10.5194/egusphere-egu2020-6600, 2020

D2130 |
EGU2020-210
Antonio Girona-García, Ana Rita Lopes, Sofia Corticeiro, Ricardo Martins, Jacob Keizer, and Diana Vieira

Wildfire patterns are shifting all over the world as a consequence, among others, of changes in land use and climate [1], which may entail remarkable social, environmental, and economic implications. The occurrence of wildfires is often linked to increased post-fire hydrological and erosive responses, which are hard to predict due to the complexity of factors involved [2]. Against this background, soil erosion models arise as a resourceful tool in the decision-making process for environments that are or could be affected by wildfires: from prevention to mitigation and from emergency actions to long-term planning. Nevertheless, the current soil erosion models were not originally developed for post-fire conditions, so they are not adapted to include fire-related changes into their predictions [3]. This work aimed to review the scientific advances in the last twenty years in post-fire soil erosion modelling research from a meta-analysis approach.

To this end, the Scopus database was searched using different combinations of the terms “model”, “modelling”, “fire”, “wildfire” “hydrology”, “erosion”, “runoff”, “burn”, “burnt”, “erosion”, “soil erosion”, “sediment” and “rill”. Afterwards, the following publications were excluded: a) reviews; b) journals without peer-review process; c) books or book chapters; d) reports; e) editorials; f) conference proceedings; g) works in which the modelling was conducted on individual processes; h) studies modelling debris flows and landslides; i) works that did not conduct post-fire and/or erosion modelling; j) works that are not in English. Then, it was identified whether authors included in the models important factors related to soil erosion in fire-affected environments such as changes in water infiltration, burn severity, and/or the application of post-fire mitigation treatments. The main modelling approaches used, the calibration and validation of predicted data, and the use of efficiency indexes were also evaluated. 

The screening resulted in 33 works (43 cases based on the model used) that were not homogeneously distributed worldwide, neither according to the model type used, nor by regions most affected by wildfires. For the calibration process, in 70% of the cases models were adapted to burned conditions but only in 25% of them, individual input parameters were improved to accommodate processes that were not previously represented. Additionally, burn severity and changes in infiltration were considered in 77 and 65% of the cases, respectively, whereas only 26% of the cases corresponded to studies where post-fire mitigation treatments were applied. It is noteworthy that only in 19% of the cases, the predicted data were validated with independent field datasets and uncertainty was assessed in 5% of the studies.

It is highlighted that further efforts are required on the adaptation of erosion models to burned conditions, evaluating the model performance in both calibration and validation stages for a wider variety of environments and scenarios, in order to accurately predict the hydrological and erosive response after fires.

[1] Andela et al. (2017). Science 356: 1356-1362. DOI: 10.1126/science.aal4108

[2] Larsen & MacDonald (2007). Water Resour. Res. 43: W11412. DOI: 10.1029/2006WR005560

[3] Vieira et al. (2018). Environ. Res. 165: 365-378. DOI: 10.1016/j.envres.2018.04.029

How to cite: Girona-García, A., Lopes, A. R., Corticeiro, S., Martins, R., Keizer, J., and Vieira, D.: What is wrong with post-fire soil erosion modelling? , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-210, https://doi.org/10.5194/egusphere-egu2020-210, 2019

D2131 |
EGU2020-11537
Diana Vieira, Marta Basso, João Nunes, Jacob Keizer, and Jantiene Baartman

Wildfires are known to change post-fire hydrological response as a consequence of fire-induced changes such as soil water repellence (SWR). SWR has also been identified as a key factor determining runoff generation at plot and slope scale studies, in which soil moisture content (SMC) has been presented as dependent variable. However, these relationships have not been established at catchment scale yet, mainly due to the inherent difficulties in monitoring post-fire hydrological responses at this scale and in finding relationships between these events with SWR point (time and space) measurements. To fulfil these knowledge gaps, the present study aims to advance the knowledge on post-fire hydrological response by simulating quick flows from a small burned catchment using a physical event-based soil erosion model (OpenLISEM).

OpenLISEM was applied to simulate sixteen events with two distinct initial soil moisture conditions (dry and wet), in which the model calibration was performed by adjusting Manning’s n and saturated soil moisture content (thetas). Considering that manual calibration resulted in distinct Manning’s n for wet and dry conditions, while thetas required an individual calibration for each event, an alternative parameterization of thetas was created by means of linear regressions, for all the events together (“overall”), and for wet and dry events separately (“wet” and “dry”). Model performance was evaluated at the outlet, while hillslope predictions were compared with runoff data from micro-plots that were installed at 3 of the hillslopes (Vieira et al., 2018).

The validation of field data at micro-plot scale revealed several comparability limitations attributed to the time-step of the field data (1- to 2-weekly) in comparison to the duration of the events (170-940 min). Nevertheless, the most striking result from our simulations is the fact that OpenLISEM did not predict overland flow generation at two out of the three locations where it was observed. Our simulations also showed that the forest roads are a source of the runoff generation and their configuration affects catchment connectivity.

At the outlet level, OpenLISEM achieved a satisfactory (0.50 < NSE ≤ 0.70) and very good (NSE > 0.80) model performance according to Moriasi, et al. (2015), in predicting total discharge (NSE=0.95), peak discharge (NSE=0.68), and the time of the peak (NSE=1.00), for the entire set of events under manual calibration. In addition, simulations in wet conditions achieved higher accuracy in comparison to the dry ones.

When using the parameterization based on the linear regression calibration, OpenLISEM simulation efficiency dropped, but still to satisfactory and very good (NSEoverall = 0.58, NSEcombined =0.86) accuracy levels for total discharge.

Overall, we conclude that calibrating post-fire hydrological response at catchment scale with the OpenLISEM model, can result in reliable simulations for total flow, peak discharge and timing of the peaks. When considering the parameterization of thetas as proxy for repellent and wettable soils, more information than the initial soil moisture is required.

How to cite: Vieira, D., Basso, M., Nunes, J., Keizer, J., and Baartman, J.: Event runoff calibration with LISEM in a recently burned Mediterranean forest catchment., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11537, https://doi.org/10.5194/egusphere-egu2020-11537, 2020

D2132 |
EGU2020-19462
Jan Keizer, Ricardo Martins, Adriana Xavier, Diana Vieira, Ana Miranda, Sandra Sorte, Carlos Borrego, Luís Correia, Fábio Morgado, Sandra Rafael, and Micael Rebelo

The Portuguese ASHMOB project (CENTRO-01-0145-FEDER-029351) is addressing the overall lack of knowledge on the mobilization of wildfire ash with time since fire. More specifically, ASHMOB is looking into the lateral transport of wildfire ash by water as well as wind erosion. ASHMOB involves a combined measurement-modeling approach comprising five phases: (i) wildfire ash collection and characterization; (ii) wind tunnel experiments of ash mobilization by wind erosion; (iii) hydraulic laboratory experiments of ash mobilization by rainfall splash, run-on and their combination; (iv) adjusting selected wind and water erosion models to accommodate erosion of wildfire ash; (v) validating the adjusted models by field measurements in a recently burnt area.  The current presentation concerns the second phase and, in particular, wind tunnel experiments aiming to assess the influence of water content on the post-fire ash mobilization. The experiments were performed in the wind tunnel of the Atmosphere Aerodynamics Laboratory of Aveiro University’s Department of Environment and Planning, which is an open-circuit wind tunnel with 13 m long and a test section of 6.5x1.5x1.0 m (LxWxH), often used for physical modelling of urban flows and air quality. For these experiments, wildfire ash was used from three different land cover types, i.e. Maritime Pine and Eucalypt forest plantations and Strawberry tree woodlands (or, more concretely, woodland patches). These ashes were collected as soon as possible after three wildfires that occurred during the summer of 2019 in central Portugal, typically within 2 weeks. The pine, strawberry tree and eucalypt ashes were collected following wildfires in july in Vila de Rei, august in Fátima and september in Albergaria-a-Velha, respectively. The experiments involved one specific ash load of 10 mm, based on findings of earlier experiment with varying ash loads, and ash-to-water ratio of 1:0, 1:0.25, 1:0.5, 1:0.75, 1:1, 1:1.5 and 1:2 (wash/wwater) at the start of the experiments. Ash mobilization with stepwise increasing wind speeds up till 9 m.s-1 was measured continuously using a measurement scale linked to a computer and was also filmed from above using a Go-Pro video camera. For each combination of ash type and ash-to-water ratio, 5 replicate experiments were run. Preliminary analysis of the obtained results revealed a clear role of water content in the mobilization by wind of all three types of wildfire ash, with marked increased shear velocity with increasing ash-to-water ratio. At the same time, shear velocity also differed markedly between the woodland types, with consistently lower shear velocity for pine ash than for eucalypt as well as strawberry tree ash at the different ash-to-water ratios.

How to cite: Keizer, J., Martins, R., Xavier, A., Vieira, D., Miranda, A., Sorte, S., Borrego, C., Correia, L., Morgado, F., Rafael, S., and Rebelo, M.: The role of water content in wildfire ash mobilization by wind erosion under laboratory conditions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19462, https://doi.org/10.5194/egusphere-egu2020-19462, 2020

D2133 |
EGU2020-22501
Antonio Parra, María Belén Hinojosa, Iván Torres, and José Manuel Moreno

Post-fire regeneration often occurs under water scarcity conditions in Mediterranean ecosystems. This fact is likely to be more frequent in the future, as climate change projections for the Mediterranean show increased temperature and decreased rainfall, as well as higher fire weather danger. Therefore, studying how vegetation responds to fire and drought is critical for anticipating vegetation vulnerability to global warming. Here, we present the results of a manipulative field study in a Mediterranean shrubland of Central Spain in which 4 drought treatments were imposed before and after carrying out an experimental burning of the treated plots: natural rainfall, historical rainfall regime (2 months summer drought per year), moderate drought (ca. 25% rainfall reduction from historical records, 5 months drought), and severe drought (ca. 50% rainfall reduction, 7 months drought). We monitored the plant community during the first 4 years after fire under the drought treatments followed by additional 6 years once such treatments had ceased. We found that drought significantly reduced density, cover, and size of seeder species during the first post-fire years under treatment. In contrast, resprouter species were virtually unaffected. As a whole, the changes in woody species dynamics resulted in a community ‘herbalization’, which was richer and more diverse, but probably more prone to a new fire. Moreover, we found that the drought effects on the community, and especially on the seeders, were maintained various years after all plots started receiving natural rainfall. 10 years after the fire, the legacy effect of the drought had been diluted, although some effects on plant density or cover in certain seeder species were still present. Overall, this means that what happens during the first few years after fire is extremely important for vegetation recovery, and that the effects of a long drought can persist over various years, and likely over a whole fire cycle.

How to cite: Parra, A., Hinojosa, M. B., Torres, I., and Moreno, J. M.: Drought legacy effects on post-fire vegetation dynamics in a Mediterranean shrubland of Central Spain, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22501, https://doi.org/10.5194/egusphere-egu2020-22501, 2020

D2134 |
EGU2020-1295
Domina Delač, Paulo Pereira, and Ivica Kisić

The effects of mulch (Olea europea and Pinus halepensis) on burned soils: A preliminary study in Adriatic coast (Croatia)

Delac, Domina1*; Pereira, Paulo2*; Kisic, Ivica1

1University of Zagreb, Faculty of Agriculture, Department of General Agronomy, Svetosimunska cesta 25, 10000 Zagreb, Croatia. (*ddelac@agr.hr)

2Mykolas Romeris University, Environmental Management Laboratory, Ateitis street 20, LT-08303, Vilnius, Lithuania (*pereiraub@gmail.com)

 

In the recent decades the frequency and intensity of summer drought periods is increasing in Adriatic coast. These changes in climate increase the vulnerability to wildfires. Wildfires can change soil physical and chemical properties. However, these effects can be mitigated by mulching. The aim of this work is to study the effects of mulch (Olea europea and Pinus halepensis) on fire affected soils. The wildfire occurred on 28 July 2019 and affected an area of about 900 ha in Dalmatia, near Adriatic Coast (43°45'06.0"N 15°56'02.9"E with an elevation of 105 m a.s.l.).  The mean annual temperature is 15.8 °C, and the annual precipitation is 800 mm. It was affected agricultural land with dominant culture Olea europea and abandoned grassing where dominates Pinus halepensis. Soils are classified as calcocambisols. Twenty-five days after the fire, two plots (5 treatments per plot) were established and covered with Olea europea and Pinus halepensis mulch. A control plot was established as well. Soil were sampled (0 – 5 cm), twenty- days after fire (August, 2019), before mulch application, and then 3 months after fire (November, 2019). A total of 15 samples were collected per treatment (45 each sampling date). The soil properties analysed were soil pH, soil organic matter (SOM), mean weight diameter (MWD) to express aggregate stability, and soil water repellency (SWR) measured with water drop penetration time method (WDPT) in different fractions (2 – 1 mm; 1 – 0.5 mm, 0.5 – 0.25 mm, and <0.25 mm). Soil pH was not significantly different among sampling dates and treatments. SOM was significantly different among sampling dates for Olea europeae treatment and control. Olea europeae treatment had a significantly higher SOM then Pinus halepensis and control treatment. MWD was significantly higher within Olea europeae treatment. Within Pinus halepensis and control treatment no significant difference was observed. The soil was classified as slightly water repellent (5 – 60 seconds) in Olea europeae soil finer fraction (0.5 – 0.25 mm and <0.25) in both sampling dates. In Pinus halepensis treatments and control, soil was wettable (<5 seconds), and no significant difference was observed among sampling date. Future sampling and analysis will be conducted during one year to estimate the effect of Olea europeae and Pinus halepensis mulch on soil properties.

Keywords: Wildfire, Olea europeae, Pinus halepensis, mulch.

 

Acknowledgments

This work was supported by Croatian Science Foundation through the project "Influence of Summer Fire on Soil and Water Quality” (IP-01-2018-1645).

How to cite: Delač, D., Pereira, P., and Kisić, I.: The effects of mulch (Olea europea and Pinus halepensis) on burned soils: A preliminary study in Adriatic coast (Croatia), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1295, https://doi.org/10.5194/egusphere-egu2020-1295, 2019

D2135 |
EGU2020-5814
Marcos Francos, Xavier Úbeda, Paulo Pereira, Victoria Arcenegui, and Jorge Mataix-Solera

Forest mechanical fuel treatments in Mediterranean ecosystems are frequently employed to reduce both the risk and severity of wildfires. These pre-fire treatments may influence the effects of wildfire events on soil properties. The aim of this study is to examine the effectivity of this treatment (clear-cutting operation whereby part of the vegetation was cut and left covering soil surface) carried out before a wildfire that broke out in 2015 and evaluate if the management had influence on post-wildfire soil properties of three sites: two exposed to management practices in 2005 (site M05B) and in 2015 (site M15B)–and one that did not undergo any management (NMB) and to compare their properties with those recorded in a Control area unaffected by 2015 wildfire. The fourth areas were sampled and compared 2, 10 and 18 months after wildfire. The study area is located in Ódena (Catalonia, Spain). The wildfire occurred at July 27th of 2015 and burned 1237 ha. In each area and in each sampling moment we collected 9 topsoil samples (0-5 cm depth). We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (Cmic) and basal soil respiration (BSR). Two-way ANOVA was carried out to check the differences according to sampling moment and to management. The results show that 2 months after the wildfire M05B showed greater amount of IC and pH; M15B showed greater Na than the other areas; NMB resulted higher in AS, TN, SOM, EC, Ca, Mg, K and BSR; and Control registered the highest Cmic. C/N resulted similar in the 4 areas in the three sampling moments. Ten months after wildfire, M05B showed greater AS and IC; NMB resulted higher in TN, SOM, EC, Mg and K; and Control showed higher pH, Ca, Na, Cmic and BSR. In the last sampling, 18 months after wildfire, M05B showed greater pH; M15B showed higher AS; NMB resulted higher in TN, SOM, EC, Ca and K; and Control showed higher IC, Mg, Na, Cmic and BSR. According to the treatments M05B registered higher TN, SOM, IC, EC, Mg, Na and K during 1st sampling; AS and C/N during 2nd sampling; and pH, Ca, Cmic and BSR during 3rd sampling. M15B registered higher IC, Mg, Na and K during 1st sampling; BSR and C/N during 2nd sampling; and AS, TN, SOM, pH, EC, Ca and Cmic during 3rd sampling. NMB registered higher IC, Mg, Na, K, Cmic and BSR during 1st sampling; AS and C/N during 2nd sampling; and TN, SOM, pH, EC and Ca during 3rd sampling. Control did not vary significantly over time due to the absence of perturbation. Overall, a comparison of the pre-fire treatments showed that NMB was the practice that had the least negative effects on the soil properties studied, followed by M15B, and that fire severity was highest at M05B due to the accumulation of dead plant fuel.

How to cite: Francos, M., Úbeda, X., Pereira, P., Arcenegui, V., and Mataix-Solera, J.: Pre-fire forest management effectivity to decrease wildfire impact on soil properties in a Mediterranean forest., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5814, https://doi.org/10.5194/egusphere-egu2020-5814, 2020

D2136 |
EGU2020-11035
Henry Grover, Matthew Bowker, Peter Fulé, Kyle Doherty, Carolyn Sieg, and Anita Antoninka

With wildfires increasing in extent and severity in the Southwestern USA, practitioners need new tools to rehabilitate recently burned ecosystems. Fire mosses consist of three species, Ceratodon purpureus, Funaria hygrometrica, and Bryum argenteum, that naturally colonize burned landscapes, aggregate soils, and can be grown rapidly in the greenhouse. We explored the efficacy of fire moss as a passive and active postfire rehabilitation tool. First, we conducted a natural survey of moss colonization and function on 10 severely burned areas in the Southwestern USA. We tested 11 landscape scale predictors of fire moss cover and found that it is most strongly influenced by insolation, pre-fire vegetation type, soil organic carbon, and time since fire. We also found that, when compared to bare soils, fire mosses increase infiltration by 50% on average and soil stability by more than 100%. Using this information, we selected two study sites on which to inoculate greenhouse grown fire moss. Directly after a wildfire near Flagstaff, Arizona we added sieved moss, finely ground moss, and moss combined with diatomaceous earth and rolled into pellets (n=15). After two years of growth, B. argenteum was the only successful species and no treatment had attained more than 1% cover on average, pellet treated plots had higher moss colonization (p <.001).

Four months after a wildfire in the Jemez Mountains of New Mexico, we added greenhouse cultivated moss that was sieved as well as high and low cover of pellets (n= 12). After 1.5 years of growth, we found increased B. argenteum cover with a mean of 10.5% on plots that received high cover of pellets compared to 5.1% cover for controls (p= .02). Currently we are analyzing data to determine if this cover influenced point scale erosion and infiltration metrics. Our results indicate that fire mosses are functionally important colonizers of north facing severely burned hillslopes, however more research is necessary to develop them as an active rehabilitation tool.

How to cite: Grover, H., Bowker, M., Fulé, P., Doherty, K., Sieg, C., and Antoninka, A.: Post-fire moss colonization and rehabilitation in forests of the Southwestern USA , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11035, https://doi.org/10.5194/egusphere-egu2020-11035, 2020

D2137 |
EGU2020-20618
Dalila Serpa, Jan J. Keizer, Ana I. Machado, Martha Santos, Bruna R. F. Oliveira, Behrouz Gholamahmadi, Martinho Martins, Oscar González-Pelayo, and Life-Reforest Consortium

Recently burnt areas have frequently been documented to produce strong to extreme catchment-scale hydrological and erosion responses to major rainfall events, even if these responses have rarely been quantified. These responses have raised important concerns, both among forest owners and managers on the on-site implications of soil (fertility) loss and among water resources managers for the off-side impacts on downstream values-at-risk such as road and hydraulic infrastructures, flood zones, and surface water quality in reservoirs or at river intake points. State-of-the-art emergency stabilization management, as practiced in the USA and Galicia, aims at reducing the hydrological and erosion response at its main source, i.e. the hillslopes. Based on years and decades of experience and pain-staking field monitoring in both the USA and Galicia, mulching is typically preferred over barrier-based methods, especially for being more effective in the case of high-intensity rainfall storms. Even so, the LIFE-REFOREST consortium (LIFE17 ENV/ES/000248) has developed an innovative barrier-based technique that is designed to be implemented easier and faster than log and shrub barriers and, at the same time, to improve vegetation recovery, using seeds of plant species that establish vegetation strips against runoff and erosion and/or seeds of tree and shrub species for re- or afforestation. The REFOREST barriers consists of geotubes containing, besides seeds, a mycotechnosoil as well as straw. The effectiveness of the LIFE-REFOREST geotubes is current being tested under field conditions in summer-2019 burnt areas in north-central Portugal and Galicia, in contrasting forest types (eucalypt vs. pine) on contrasting parent materials (schist vs. granite). Both field trials involve, besides 3 control plots and 3 plots with geotubes, also 3 plots mulched with either eucalypt logging residues or pine needles. The present poster will show preliminary results of the field trial in north-central Portugal, in a second-rotation eucalypt stand where tree crowns were scorched by the fire and soil burn severity was classified as moderate. These results concern the initial monitoring period till early spring 2020. However, this monitoring period has been quite rainy so far, arguably providing rather ideal conditions for testing the effectiveness of barrier-based solutions such as that of LIFE-REFOREST.

How to cite: Serpa, D., J. Keizer, J., I. Machado, A., Santos, M., R. F. Oliveira, B., Gholamahmadi, B., Martins, M., González-Pelayo, O., and Consortium, L.-R.: Testing a novel technique, geotubes with mycotechnosoil, to mitigate post-fire erosion and enhance ecosystem recovery, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20618, https://doi.org/10.5194/egusphere-egu2020-20618, 2020