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We investigated the influence of fire severity, logging of burnt wood, local ecological factors and their interaction on the natural regeneration, survival and growth of maritime pine (Pinus pinaster Ait.), following a fire that took place in 2005. During the period 2006–2020, a sample of 1900 seedlings were monitored, in which three post-fire treatments were applied: (1) Early logging (before seedling emergence); (2) Delayed logging (after emergence); and (3) No management. Multivariate semi-parametric and non-parametric techniques were used to model seedling survival, estimated density and growth of natural pine regeneration. Seedling survival was 31% with a mean density of more than 2000 seedlings/ha at the end of the study period. Logging before seedling emergence was positively related with pine survival and density. Delayed logging resulted in the lowest seedling density and regeneration. Fire severity had a negative influence on regeneration density. The findings indicate that site conditions and fire severity have a stronger influence on natural regeneration of maritime pine than subsequent post-fire management treatments. In order to ensure the presence of maritime pine in pure or mixed stands, silvicultural work is required to control competition from other species and reduce the risk of new wildfires. [ABSTRACT FROM AUTHOR]

Context: Wildfires have severe impacts on landscapes' hydrological and sediment processes. They are linked to events such as flash floods and droughts, and high erosion rates which lead to loss of soil organic matter and detachment of seeds and seedlings. Mulching is an effective measure implemented directly after a fire to reduce soil erosion and increase soil water retention. However, its implementation has proved a challenge, mainly due to factors such as cost and public acceptance. Objectives: This research aims to optimize the application of post-fire mulching by using decision-making criteria to select "how" and "where" the technique should be used. The specific objectives were to: (i) investigate the decision-making criteria on "how" to apply mulch by interviewing experts; (ii) define the cost-effectiveness relations of erosion modelling scenarios. Methods: The Monchique 2003 wildfire in Southern Portugal was used as a case study Experts' interviews and literature review were used to construct prioritization scenarios. Post-fire soil erosion was then modelled with the Revised Universal Soil Loss Equation (RUSLE) model and the Sediment Connectivity Index for the three resulting scenarios (the "Soil" scenario, considering the net potential erosion; the "Water" scenario, focusing on th1e protection of water bodies from sedimentation; and the "Road" scenario, focusing on road protection); and at two erosion thresholds (1 and 10 Mg ha−1 year−1). Results: The interviews and the literature review highlighted the importance of socio-economic parameters when it comes to mulch application. Moreover, models showed that small interventions, aimed at areas nearby water bodies and road networks can be more cost-effective than large interventions. Conclusions: Models helped to create a hierarchy of scenarios, enabling land managers to assess decision making tools at the landscape level, linking their priorities with practical issues of emergency stabilization practices. [ABSTRACT FROM AUTHOR]

Few studies have compared the variability of soil properties using different types of mulches in semi-arid forests. This study evaluated the changes in physico-chemical soil properties in a semi-arid forest of Central Eastern Spain, where straw and pine wood chips were distributed as mulch three months after a wildfire. Soils were sampled under burned and unmulched and burned and mulched plots three and nine months after the treatments. The data was processed using Principal Component Analysis (PCA) and Analytical Hierarchical Cluster Analysis (AHCA). Mulching with straw or wood chips did not have any significant effects on the texture and chemical properties of burned sites few months after the treatment. In contrast, significant changes are expected over time in organic matter, nutrients and many ions. There were no significant differences in soil properties between the two mulches. These low changes were confirmed by PCA coupled with AHCA, which did not show a clear distinction among the three soil conditions. However, a noticeable and significant variability of many of these properties over time was evident. This study shows that mulching does not degrade of soil properties in the short-term after a wildfire and after post-fire treatments, and thus helps protect semi-arid forest ecosystems against the negative impacts of high-severity fires. [ABSTRACT FROM AUTHOR]

In Mediterranean areas, fire has increased soil degradation and erosion. For this reason, the application of soil quality indices can help to determine soil recovery and degradation levels. By using a multiparameter soil quality index fitted to undisturbed forest soils, we can show the right information on soil functionality. In this study, the objectives were to evaluate soil functionality after suffering a fire, to subsequently treat with various soil treatments (wood mulching), and then check a soil quality index (SQI) to assess the soil quality recovery in burned Pinus nigra stands. For this purpose, a burned area was selected in the Cuenca Mountain range (Spain) under a Mediterranean climate. Experimental plots were established in the study area, with three slope gradients and applying three methods of covering soil using: (1) wood chips; (2) piles of branches; and (3) trunks of contour-felled logs. The experiment was conducted for 4 years. Results showed that the properties of soil were enhanced under wood chips and logs as a surface-covering material, and in a short time (less of 3 years). In consequence, the values of the SQI index were higher after applying these two treatments, thus reflecting the effectiveness of the SQI for monitoring post-fire recovery. [ABSTRACT FROM AUTHOR]

We investigated the influence of fire severity, logging of burnt wood, local ecological factors and their interaction on the natural regeneration, survival and growth of maritime pine (Pinus pinaster Ait.), following a fire that took place in 2005. During the period 2006–2020, a sample of 1900 seedlings were monitored, in which three post-fire treatments were applied: (1) Early logging (before seedling emergence); (2) Delayed logging (after emergence); and (3) No management. Multivariate semi-parametric and non-parametric techniques were used to model seedling survival, estimated density and growth of natural pine regeneration. Seedling survival was 31% with a mean density of more than 2000 seedlings/ha at the end of the study period. Logging before seedling emergence was positively related with pine survival and density. Delayed logging resulted in the lowest seedling density and regeneration. Fire severity had a negative influence on regeneration density. The findings indicate that site conditions and fire severity have a stronger influence on natural regeneration of maritime pine than subsequent post-fire management treatments. In order to ensure the presence of maritime pine in pure or mixed stands, silvicultural work is required to control competition from other species and reduce the risk of new wildfires.

It is well known how fires affect the properties of forest soils depending on its severity. A better understanding of the magnitude of these impacts is essential to setup effective management actions after fire against the losses of soil and biodiversity. However, physical, chemical and biological processes in burnt soils are complex, resulting in a diversity of fire-induced changes, as acknowledged in many literature studies. Moreover, these changes may be even variable between natural forests and reforested areas. This study explores the changes in the most important soil properties with fire severity, from low to high. The main chemical parameters of soils were measured after field sampling in different pine forests (burnt natural stands, reforested areas as well as unburnt sites) of Castilla La Mancha (Central Eastern Spain). In comparison to the unburnt soils, the investigation has shown in the burnt areas: (i) no evident changes in soil pH at all fire severities, except in natural stands burnt at a very high severity (showing an increase of about 10%); (ii) increases in the organic carbon content (by about 70%) of soils burnt at a moderate fire severity under both forest ecosystems, and in reforested areas at very high fire severities (+95%); (iii) small differences in the nitrogen content of soil, except for a significant increase measured in soils burnt at an moderate fire severity under both the natural pine stand and reforested area (about +300%); (iv) a limited variability of the phosphorous content in the soil, with only an increase in soils under natural pine stands burnt at moderate fire severity (by 250%); (v) increases in magnesium and potassium contents in soils burnt at the highest fire severities for both land conditions, and decreases in calcium content in reforested areas burnt at the highest severity. Due to some negative impacts (increase in pH and decrease in organic carbon), the implementation of post-fire management actions at natural pine stands burnt at the highest fire severity should be a priority over reforested areas. Overall, this study did not show a straightforward pattern between soil properties, fire severity and land condition. This means that other parameters (for instance, the hydrological properties of soils) that were not explored in this investigation could have played an important role, and therefore must be taken into consideration when defining post-fire management actions.

To avoid flooding and erosion hazards, post-fire management actions are essential in Mediterranean forests after severe wildfires. In this regard, mulching is the most common action but some mulch materials, such as straw, may lead to adverse impacts in burned forests. The use of yellow mistletoe fruits (Loranthus europaeus Jacq., hereafter "LE") for the production of biodegradable mulch and its effectiveness in post-fire hydrology have never been studied. To fill this gap, this study has evaluated surface runoff and rainsplash erosion in a pine forest in Central Eastern Spain burned by a wildfire and mulched by a mixture of LE fruits and straw (with or without adding clay particles) using a portable rainfall simulator. Compared to untreated sites, runoff increased in burned and mulched soils (by 13.6% for the mixture without clay and by 17.2% when clay was added, in the latter case significantly). This increase was mainly due to the compact layer created by mulch application on the soil surface. However, the peak flow and the time to peak were lower in mulched soils (on average by 32.7% and 60.5%, significantly only for the mulch mixture without clay), thus indicating that, in these soils, peak runoff takes longer and its maximum value is lower compared to untreated sites. Soil erosion noticeably and significantly decreased (up to 97%) in mulched areas in comparison to untreated sites without significant differences between the two mixtures. Overall, this study indicates to land managers that soil mulching with a mixture of Loranthus europaeus Jacq. and straw is an effective post-fire management action to reduce the soil erosion risk after a wildfire. [ABSTRACT FROM AUTHOR]

Post-fire harvest (PFH) is a forest management practice designed to salvage value from burned timber, mitigate safety hazards from dead trees, reduce long-term fuels, and prepare sites for replanting. Despite public controversy and extensive ecological research, little is known about how much PFH occurs on private and public lands in the U.S. Pacific West, or how practices changed with shifting forest policy and increasing area burned over the last three decades. We mapped PFH across 2.2 M burned hectares in California, Oregon, and Washington between 1986–2017 and used time series intervention analysis to compare trends in area, rate (% of burned area harvested), and mean patch size between private (0.5 M ha) and federal (1.6 M ha) forest land and across a gradient of burn severity. Harvest rates varied by ownership (4.9% federal, 18.6% private, 8.0% overall), and practices evolved and diverged over the study period. PFH area and rate declined across all ownerships in the mid-1990s during a period of reduced fire activity. As area burned increased between the early 2000s and late 2010s, PFH area rebounded and surpassed late-1980s levels, while rates remained relatively low. On federal lands, PFH practices shifted in the early-to-mid 1990s towards lower rates (10.3%–3.8%) and smaller patches (6.0–3.3 ha), following policy changes and increased litigation. PFH rates on federal lands decreased at all levels of burn severity, with the largest decreases (6.2%–1.2%) in forests with low tree mortality (i.e. fire refugia). Conversely, private PFH rates and mean patch sizes more than doubled in forests burned at very low-to-moderate severity. Our results highlight how PFH practices have shifted with policy, socio-economic pressure, and increasing area burned over 31 years in the Pacific West. A similar area of PFH is now dispersed over larger fires, with practices diverging substantially between ownerships.

The effects of fire on soil hydraulic conductivity (K) and soil water repellency (SWR) have been mainly studied by field experiments in forest areas burned by wildfires with a given severity, while the variability of K and SWR with the fire severities has been less investigated. To fill this gap, the changes in the K and SWR with fire severity and soil depth (1 and 5 cm below the ground surface) have been evaluated in two forest ecosystems (natural stand of pine and reforested areas) of Central Eastern Spain. A significant influence of the fire severity on the infiltration rates was found, and this influence was different between the natural stand of pine and the reforested areas. Compared to the unburned soils, the highest reduction of the K (80% to 90%) and SWR levels were found for the fires with low and intermediate severities at the soil surface. At the lower soil depth, the reduction of K and the SWR level due to fire were proportional to its severity. Moreover, the K of the soil surface layer was often higher compared to the water infiltration in the deeper layer. In the reforested areas, also low fire severities can noticeably reduce the surface K, despite the limited SWR, while the natural forests are less exposed to hydrophobicity in their surface soil layer. This study indicates the need to reduce the risk of flooding and erosion linked to a reduction in water infiltration and increase of soil repellency. [ABSTRACT FROM AUTHOR]

Understanding the role of biocrust-forming mosses in soil recovery after wildfires is necessary for assessing the resilience of managed ecosystems. The purpose of this study was to investigate the mid-term impacts of two contrasting post-fire management strategies on soil recovery in eucalypt plantations in north-central Portugal, where a high cover of biocrust-forming mosses developed post-fire, contributing to erosion control. Six years after a wildfire, we examined the legacy effects of salvage logging and two rates of mulch application using logging residues (a standard rate of 8.0 Mg ha-1 and a reduced rate of 2.6 Mg ha-1) on soil properties, and explored the interaction between moss biocrusts and forest management practices on soils. Our findings reveal the resilience of soils to physical disturbance after logging operations, with no persistent negative effects on their physicochemical properties. Although forest residue mulches showed minimal influence on soils after six years, an interesting interaction with moss biocrusts was observed. In the absence of moss cover, direct contact of wood residues with soil at the standard mulch rate promoted higher nutrient content and biochemical activity, potentially attributed to accelerated decomposition processes. Regardless of the management applied, our study highlights the role of moss biocrusts in improving soil aggregation and biochemical processes in the mid-term. However, the severe water repellency observed in these soils may have impeded further biocrust expansion. Understanding the implications of forest management practices on soil recovery after wildfires is imperative for guiding strategies aimed at promoting ecosystem recovery and resilience in fire-prone managed forest ecosystems. • Soils show resilience to logging with no lasting physicochemical impacts. • Post-fire mulching increased soil nutrient content in the absence of moss biocrusts. • Biocrust proliferation may be conditioned by the severe soil water repellency. • Moss biocrust accelerated post-fire soil recovery and improved soil functions. [ABSTRACT FROM AUTHOR]

The hydrological effects of straw mulching and salvage logging have been widely experimented in the Mediterranean forests affected by wildfires. In contrast, knowledge about the impacts of these post-fire management techniques on the physico-chemical properties of burned soils is poor, especially many years after the fire. In particular, no studies have evaluated the soil changes after the combinations of soil mulching and salvage logging after wildfires in Mediterranean forests. To fill this gap, this study explores the effects of straw mulching and salvage logging, applied individually or in combination to a burnt forest of Pinus halepensis Mill. of central-eastern Spain, on the physico-chemical properties of soil six years after a wildfire. Both the post-fire techniques significantly altered the organic matter, phosphorous, and carbonate contents of the burned soils as well as their C/N (carbon/nitrogen) ratio, while the texture and other chemical properties (pH, electrical conductivity, total nitrogen, potassium, cations/anions, and active limestone) of the soils were not significantly affected by these post-fire treatments. Organic matter (OM) and phosphorous (P) contents increased by 57% and 69%, respectively, in mulched soils in comparison to the burned but untreated plots. In logged soils, the OM increased by 27%, while P decreased by 17%. Salvage logging after straw mulching increased OM, albeit less than under the individual soil treatments (+13%), but noticeably reduced P (−39%). The C/N ratio practically underwent the same variation (+15–20%) after the combination of the two treatments. The principal component analysis and the agglomerative hierarchical cluster analysis applied to the soil properties measured in the plots under the individual and combined management show that the effects of salvage logging on soil properties appear to be more impactful compared to straw mulching. [ABSTRACT FROM AUTHOR]

On 28 July 2019, in the hinterland of Šibenik City, 900 ha were affected by wildfire of moderate to high severity. This study aims to evaluate the effects of two mulch treatments—needles of Pinus halepensis Mill. (PM) and leaves of Olea europaea L. (OM), as compared to an unmulched control (UM)—on soil quality. The study was conducted over 15 months, and soil samples were collected every 3 months. The studied soil properties were soil water repellence (SWR; composite, 1–2, 0.5–1, 0.5–0.25, <0.25 mm), soil hydraulic conductivity (SHC), mean weight diameter (MWD), water stability of aggregates (WSA), soil pH and electrical conductivity (EC), soil organic matter (SOM), total sulphur (TS), total carbon (TC), total nitrogen (TN), extractable phosphorus (P2O5), and available potassium (K2O). Six principal component analyses (PCA) were applied to observe the temporal dynamics of the soil properties studied for each sampling date. Mulching increased the aggregate stability (MWD and WSA) and improved SHC. SWR was only indicated on the first sampling date. Soil pH and EC showed high variability due to natural soil processes and vegetation regrowth. PM showed higher efficiency in increasing the TS, TC, and SOM, while OM increased soil P2O5 and K2O. Both mulch treatments increased the soil nutrient content, but the effect was variable due to the different chemical compositions of the material. Using native mulch is recommended because it improves soil quality. [ABSTRACT FROM AUTHOR]

In the Mediterranean forests, wildfires and post-fire management actions may degrade soil properties and negatively impact vegetation characteristics. These effects may reduce soil functionality and result in loss of plant diversity. Although straw mulching and salvage logging are commonly carried out in burned forests, their impacts on respiration of forest soils as well as on species richness and evenness of forest plants have been little explored. To fill these gaps, this study has evaluated the soil respiration, different soil physico-chemical properties, as well as plant diversity in a forest of Castilla La Mancha (Central Eastern Spain), burned by a wildfire and then subjected alternatively to salvage logging or straw mulching or to both techniques. Compared to the unburned soils, immediately after the fire mulching and salvage logging alone increased (+146%) and reduced the soil respiration (−9%), respectively, the latter especially in combination with mulching. However, these differences decreased over time, and the mulched and non-logged areas always showed the maximum soil respiration. The post-fire treatments also significantly influenced the main physico-chemical properties of the experimental soils. No evident changes were found for the pH of the logged and mulched soils compared to the control. Mulching coupled with logging did not modify the OM increase due to fire, while the lowest increase was measured in the logged but non-mulched areas. Mulched and non-logged soils maintained high OM and TN one year after fire, but also in areas that were treated with logging (with or without mulching) these parameters were significantly higher compared to the unburned areas. Mulching increased the species richness and evenness, especially when itis carried out without logging, in comparison to the unburned areas. Logging without mulching did not exert negative impacts on plant biodiversity, whose species richness increased and evenness was unvaried compared to the burned and unburned areas. The results of this study can provide land managers easy to measure tools such as soil respiration and plant diversity, which can serve to assess and evaluate the effectiveness of management measures that are taken post-forest fire in order to conserve the delicate ecosystems of the Mediterranean forests. [ABSTRACT FROM AUTHOR]

Prescribed fire, although having low intensity and being able to reduce the risk of wildfire may modify soil properties in the short term, with possible increases in runoff and erosion risk. Soil mulching with vegetation residues is one of the most common post-fire management strategies. Residues of fern, which is abundant on the Mediterranean forest floor, may be used to replace straw for mulching fire-affected areas. However, the effects of prescribed fires are not completely understood, and there is no data regarding the use of fern to protect soil after fire in the literature. To fill this gap, selected soil chemical parameters were analyzed, on a comparative basis, in three Mediterranean forests (pine, oak and chestnut) in Calabria (Southern Italy). These parameters were measured immediately and one year after fire in unburned, burned and not treated, and burned and mulched soils. Changes in soil chemical properties among the different treatments were significant, and the effects of the prescribed fire and mulching were dependent on the time elapsed from their application and forest species. In general, mulching was not effective in limiting the changes in the monitored soil properties compared to the pre-fire values. Each forest species showed different temporal trends in changes of soil properties. [ABSTRACT FROM AUTHOR]

Natural landscapes in the Mediterranean ecosystem have experienced extensive changes over the last two centuries due to wildfire activity. Resulting interactions between climatic warming, vegetation species, soil natural, and meteorological condition before and after a wildfire create substantial abrupt landscape alterations. This study investigates the evolution (2 days, 3, 6, 9, and 12 months after a fire) of topsoil (0–5 cm) chemical properties in burned Cambisols (Zadar County, Croatia) with respect to different wildfire severities (HS—high severity, MS—medium severity, C—unburned) and vegetation species (Quercus pubescens Willd. and Juniperus communis L.). Soil pH, electrical conductivity (EC), calcium carbonates (CaCO3), total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), copper (Cu) and zinc (Zn) were significantly higher in HS than in MS and C. Total soil potassium (TK), Fe and Ni were significantly higher in C than in HS. The increase of TOC and TN was more pronounced in Quercus p. than Juniperus c., especially in the first three months. Soil pH, EC, CaCO3, TOC, TN, and TS were most affected by wildfire severity. The distinction between C, MS and HS categories was less visible 9 and 12 months post-fire, indicating the start of the recovery of the soil system. Post-fire management and temporal recovery of the soil system should consider the obvious difference in soil disturbance under HS and MS between vegetation species. [ABSTRACT FROM AUTHOR]

The occurrence of short-interval, severe wildfires are increasing drastically at a global scale, and appear as a novel phenomenon in areas where fire historically returns in large time lapses. In forest ecosystems, these events induce drastic changes in population dynamics, which could dramatically impact species diversity. Here, we studied the effect on diversity of recent short-interval, severe wildfires (SISF), which occurred in rapid succession in the summers of 2002 and 2015 in Chilean Northern Patagonian Araucaria–Nothofagus forests. We analyzed the diversity of deadwood-dependent (i.e., saproxylic) and fire-sensitive beetles as biological indicators across four conditions: 2002-burned areas, 2015-burned areas, SISF areas (i.e., burned in 2002 and again in 2015), and unburned areas. Saproxylic beetles were collected using window traps in 2017 to 2019 summer seasons. To investigate the mechanisms underpinning the fire-related disturbance of the assemblage, we evaluated the effects of post-fire habitat quality (e.g., dead wood decomposition) and quantity (e.g., burned dead wood volume and tree density) on the abundances and species richness of the entire assemblage and also multiple trophic groups. Compared with the unburned condition, SISF drastically reduced species richness, evenness, and Shannon's diversity and altered the composition of the saproxylic beetle assemblages. The between-condition variation in composition was accounted for by a species replacement (turnover) between SISF and 2015-burned areas, but both species replacement and extinction (nestedness) between SISF and unburned areas. Dead wood decomposition and tree density were the variables with the strongest effects on the abundance and species richness of the entire saproxylic beetle assemblage and most trophic groups. These results suggest that SISF, through degraded habitat quality (dead wood decomposition) and quantity (arboreal density), have detrimental impacts on diversity and population dynamics of saproxylic beetle assemblages. Therefore, habitat loss is a central mechanism underpinning fire-related biodiversity loss in these forest ecosystems. [ABSTRACT FROM AUTHOR]

Tropical peat swamp forests, found mainly in Southeast Asia, have been threatened by recurring El Niño fires. Repeated burnings form a complex and heterogeneous landscape comprising a mosaic of burned patches of different fire frequencies, requiring fine-scale assessment to understand their impact. We examined the impact of the El Niño fires of 1998 and 2003 on a tropical peat swamp forest in northern Borneo, with the combined use of high and very high-resolution satellite images. Object-based and pixel-based classifications were compared to classify a QuickBird image. Burned patches of different fire frequencies were derived based on unsupervised classification of the principal components of multitemporal Normalized DifferenceWater Index (NDWI) data. The results show that the object-based classification was more accurate than the pixel-based classification for generating a detailed land cover map. Fire frequency had a severe impact on the number of burned patches and the residual forest cover. Larger patch area retained more residual forest cover for the burned patches. Forest structure of burned-twice patches was more severely altered compared to burnedonce patches. Two burned-once patches had a relatively promising recovery potential by natural regeneration due to higher residual forest cover, a vast number of large trees, and aboveground biomass. Except for the largest patch, rehabilitation seemed inevitable for burned-twice patches. This approach can be applied to assess the impact of multiple fires on other forest types for better post-fire forest management. [ABSTRACT FROM AUTHOR]

To avoid flooding and erosion hazards, post-fire management actions are essential in Mediterranean forests after severe wildfires. In this regard, mulching is the most common action but some mulch materials, such as straw, may lead to adverse impacts in burned forests. The use of yellow mistletoe fruits (Loranthus europaeus Jacq., hereafter “LE”) for the production of biodegradable mulch and its effectiveness in post-fire hydrology have never been studied. To fill this gap, this study has evaluated surface runoff and rainsplash erosion in a pine forest in Central Eastern Spain burned by a wildfire and mulched by a mixture of LE fruits and straw (with or without adding clay particles) using a portable rainfall simulator. Compared to untreated sites, runoff increased in burned and mulched soils (by 13.6% for the mixture without clay and by 17.2% when clay was added, in the latter case significantly). This increase was mainly due to the compact layer created by mulch application on the soil surface. However, the peak flow and the time to peak were lower in mulched soils (on average by 32.7% and 60.5%, significantly only for the mulch mixture without clay), thus indicating that, in these soils, peak runoff takes longer and its maximum value is lower compared to untreated sites. Soil erosion noticeably and significantly decreased (up to 97%) in mulched areas in comparison to untreated sites without significant differences between the two mixtures. Overall, this study indicates to land managers that soil mulching with a mixture of Loranthus europaeus Jacq. and straw is an effective post-fire management action to reduce the soil erosion risk after a wildfire.

Forest fires and post‐fire practices influence sediment connectivity (SC). In this study, we use the 'aggregated index of connectivity' (AIC) to assess SC in five Mediterranean catchments (198–1090 ha) affected by a wildfire in 2012 in south‐eastern Spain. Two temporal scenarios were considered, immediately after the fire and before post‐fire management, and 2 years after the fire including all practices (hillslope barriers, check‐dams, afforestation, salvage logging and skid trails). One LiDAR (light detection and ranging)‐derived digital elevation model (DEM, 2 m × 2 m resolution) was generated, per scenario. The five catchment outlets were established as the computation target (AICOUT), and structural and functional SC were calculated. Index outputs were normalized to make the results of the non‐nested catchments comparable (AICN‐OUT). The output analysis includes the SC distribution along the catchments and at local scale (929 sub‐catchments, 677 in the burned area), the hillslope and channel measures' effect on SC, and a sedimentological analysis using observed area‐specific sediment yield (SSY) at 10 new (built after post‐fire practices) concrete check‐dams located in the catchments (SSY = 1.94 Mg ha−1 yr−1; σ = 1.22). The catchments with more circular shapes and steeper slopes were those with higher AICN‐OUT. The structural SC maps – removing the rainfall erosivity influence – allowed evaluating the actual role played by the post‐fire practices that reduced SC (x¯= − 1.19%; σ = 0.41); while functional SC was linked to the actual change of SC (x¯= + 5.32%; σ = 0.62). Hillslope treatments resulted in significant changes on AICN‐OUT at sub‐catchment scale with certain disconnectivity. A good and positive correlation was found between the SSY and the changes of AICN‐OUT. However, the coarse DEM resolution explained the lack of effect of the rock check‐dams – located on the secondary channels – on AICN‐OUT. AICN‐OUT proved to be a useful tool for decision making in post‐fire restoration, but an optimal input data is still necessary to refine calculations. [ABSTRACT FROM AUTHOR]

On 28 July 2019, in the hinterland of Šibenik City, 900 ha were affected by wildfire of moderate to high severity. This study aims to evaluate the effects of two mulch treatments—needles of Pinus halepensis Mill. (PM) and leaves of Olea europaea L. (OM), as compared to an unmulched control (UM)—on soil quality. The study was conducted over 15 months, and soil samples were collected every 3 months. The studied soil properties were soil water repellence (SWR; composite, 1–2, 0.5–1, 0.5–0.25, 2O5), and available potassium (K2O). Six principal component analyses (PCA) were applied to observe the temporal dynamics of the soil properties studied for each sampling date. Mulching increased the aggregate stability (MWD and WSA) and improved SHC. SWR was only indicated on the first sampling date. Soil pH and EC showed high variability due to natural soil processes and vegetation regrowth. PM showed higher efficiency in increasing the TS, TC, and SOM, while OM increased soil P2O5 and K2O. Both mulch treatments increased the soil nutrient content, but the effect was variable due to the different chemical compositions of the material. Using native mulch is recommended because it improves soil quality.

The hydrological effects of straw mulching and salvage logging have been widely experimented in the Mediterranean forests affected by wildfires. In contrast, knowledge about the impacts of these post-fire management techniques on the physico-chemical properties of burned soils is poor, especially many years after the fire. In particular, no studies have evaluated the soil changes after the combinations of soil mulching and salvage logging after wildfires in Mediterranean forests. To fill this gap, this study explores the effects of straw mulching and salvage logging, applied individually or in combination to a burnt forest of Pinus halepensis Mill. of central-eastern Spain, on the physico-chemical properties of soil six years after a wildfire. Both the post-fire techniques significantly altered the organic matter, phosphorous, and carbonate contents of the burned soils as well as their C/N (carbon/nitrogen) ratio, while the texture and other chemical properties (pH, electrical conductivity, total nitrogen, potassium, cations/anions, and active limestone) of the soils were not significantly affected by these post-fire treatments. Organic matter (OM) and phosphorous (P) contents increased by 57% and 69%, respectively, in mulched soils in comparison to the burned but untreated plots. In logged soils, the OM increased by 27%, while P decreased by 17%. Salvage logging after straw mulching increased OM, albeit less than under the individual soil treatments (+13%), but noticeably reduced P (−39%). The C/N ratio practically underwent the same variation (+15–20%) after the combination of the two treatments. The principal component analysis and the agglomerative hierarchical cluster analysis applied to the soil properties measured in the plots under the individual and combined management show that the effects of salvage logging on soil properties appear to be more impactful compared to straw mulching.

• Scarce literature exists about the application time of mulching in burned forests. • Erosion decreased by 67% for timely mulching and by 33% for delayed application. • After an extremely intense rainstorm, this effectiveness was equal to 85% • Overall, straw mulching should be immediately applied after a forest wildfire. Several studies have explored the effectiveness of straw mulching against soil erosion in wildfire-affected forests as post-fire management technique. In contrast, scarce literature exists about the application time of the mulch cover, although this factor - beside climate patterns of the application site - is essential to increase mulching effectiveness. To fill this gap, this study has evaluated the soil loss in two forest sites of Castilla La Mancha (Spain), in which straw mulching was applied in two burned forests immediately after the wildfire or four months after the fire event. These sites show similar characteristics (soil burn severity, soil type, and vegetation), and thus the difference in soil erosion can be attributed to the treatments. The mulching effectiveness has been measured as the difference between the soil loss per unit of erodibility comparing unburned and untreated, and burned and mulched plots. At a comparable rainfall erosivity (difference in EI 30 between the two sites lower than 40 %), soil loss decreased by 67 % (in the case of timely distribution) and 33 % (when the action is delayed) in mulched sites compared to the untreated areas. After a rainstorm with very high erosivity (+600 % of EI 30), soil loss reduction was equal to 85 % in the case of early mulching application. This higher effectiveness of early mulching compared to the delayed application was due to the quicker post-fire regrowth of vegetation, and the increased level of incorporation of vegetal residues into the soil. This result suggests to land managers that straw mulching should be applied immediately after a wildfire in burned forests, in order to achieve the highest anti-erosive effects. Further research is suggested to validate these results in other environments and after application of other mulches. [ABSTRACT FROM AUTHOR]

Natural landscapes in the Mediterranean ecosystem have experienced extensive changes over the last two centuries due to wildfire activity. Resulting interactions between climatic warming, vegetation species, soil natural, and meteorological condition before and after a wildfire create substantial abrupt landscape alterations. This study investigates the evolution (2 days, 3, 6, 9, and 12 months after a fire) of topsoil (0–5 cm) chemical properties in burned Cambisols (Zadar County, Croatia) with respect to different wildfire severities (HS—high severity, MS—medium severity, C—unburned) and vegetation species (Quercus pubescens Willd. and Juniperus communis L.). Soil pH, electrical conductivity (EC), calcium carbonates (CaCO3), total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), copper (Cu) and zinc (Zn) were significantly higher in HS than in MS and C. Total soil potassium (TK), Fe and Ni were significantly higher in C than in HS. The increase of TOC and TN was more pronounced in Quercus p. than Juniperus c., especially in the first three months. Soil pH, EC, CaCO3, TOC, TN, and TS were most affected by wildfire severity. The distinction between C, MS and HS categories was less visible 9 and 12 months post-fire, indicating the start of the recovery of the soil system. Post-fire management and temporal recovery of the soil system should consider the obvious difference in soil disturbance under HS and MS between vegetation species.

Forest are highly vulnerable to global change drivers, such as an increase in wildfire events. Learning more about how and why different post‐fire management strategies regulate the ability of forest ecosystem properties (e.g. plant diversity and function) to simultaneously recover after wildfire and provide multiple ecosystem functions is of critical importance.This study aims to evaluate how unburned, burned managed and burned unmanaged plots regulate the responses of multiple forest ecosystem properties (e.g. plant diversity, nutrient cycling, soil carbon stocks, water regulation, decomposition and wood production) and overall multifunctionality to wildfires. In September 2017, we selected two post‐fire management strategies in a 3‐km2 watershed previously affected by a wildfire in July 2012: contour‐felled log debris (CFD), log erosion barriers area (LEB), and also unburned and unmanaged plots (BNA). We randomly distributed 12 plots among the three post‐fire management strategies (three plots per treatment) and unburned.The results showed that multiple forest ecosystem properties were significantly affected by wildfire and that specific post‐fire management treatment (e.g. LEB and CFD) can be used to efficiently support plant diversity and ecosystem functioning. Our results revealed that the general indicators of ecosystem functions decreased in Mediterranean forests after wildfires and post‐fire management strategies (LEB and CFD) significantly helped to recover the ecosystems' short‐term community‐level properties and ecosystem functions (5 years after a wildfire event) to pre‐fire levels.Synthesis and applications. These findings demonstrate that multiple ecosystem functions are affected by wildfires in Mediterranean forests and show that post‐fire management treatments can promote multifunctionality and plant diversity. Our results unfold the potential of log erosion barriers (LEB) and contour‐felled log debris (CFD) as effective strategies for recovering community‐level properties and forest functions in the short term. [ABSTRACT FROM AUTHOR]

Runoff and erosion processes can increase after wildfire and post‐fire salvage logging, but little is known about the specific effects of soil compaction and surface cover after post‐fire salvage logging activities on these processes. We carried out rainfall simulations after a high‐severity wildfire and post‐fire salvage logging to assess the effect of compaction (uncompacted or compacted by skid traffic during post‐fire salvage logging) and surface cover (bare or covered with logging slash). Runoff after 71 mm of rainfall across two 30‐min simulations was similar for the bare plots regardless of the compaction status (mean 33 mm). In comparison, runoff in the slash‐covered plots averaged only 22 mm. Rainsplash in the downslope direction averaged 30 g for the bare plots across compaction levels and decreased significantly by 70% on the slash‐covered plots. Sediment yield totalled 460 and 818 g m−2 for the uncompacted and compacted bare plots, respectively, and slash significantly reduced these amounts by an average rate of 71%. Our results showed that soil erosion was still high two years after the high severity burning and the effect of soil compaction nearly doubled soil erosion via nonsignificant increases in runoff and sediment concentration. Antecedent soil moisture (dry or wet) was the dominant factor controlling runoff, while surface cover was the dominant factor for rainsplash and sediment yield. Saturated hydraulic conductivity and interrill erodibility calculated from these rainfall simulations confirmed previous laboratory research and will support hydrologic and erosion modelling efforts related to wildfire and post‐fire salvage logging. Covering the soil with slash mitigated runoff and significantly reduced soil erosion, demonstrating the potential of this practise to reduce sediment yield and soil degradation from burned and logged areas. [ABSTRACT FROM AUTHOR]

The extensive afforestation of the Mediterranean rim of Europe in recent decades has increased the number of wildfire disturbances on hydrological and sediment processes, but the impacts on headwater catchments is still poorly understood, especially when compared with the previous agricultural landscape. This work monitored an agroforestry catchment in the north‐western Iberian Peninsula, with plantation forests mixed with traditional agriculture using soil conservation practices, for one year before the fire and for three years afterwards, during which period the burnt area was ploughed and reforested. During this period, continuous data was collected for meteorology, streamflow and sediment concentration at the outlet, erosion features were mapped and measured after major rainfall events, and channel sediment dynamics were monitored downstream from the agricultural and the burnt forest area. Data from 202 rainfall events with over 10 mm was analysed in detail. Results show that the fire led to a notable impact on sediment processes during the first two post‐fire years, but not on streamflow processes; this despite the small size of the burnt area (10% of the catchment) and the occurrence of a severe drought in the first year after the fire. During this period, soil loss at the burnt forest slopes was much larger than that at most traditionally managed fields, and, ultimately, led to sediment exhaustion. At the catchment scale, storm characteristics were the dominant factor behind streamflow and sediment yield both before and after the fire. However, the data indicated a shift from detachment‐limited sediment yield before the fire, to transport‐limited sediment yield afterwards, with important increases in streamflow sediment concentration. This indicates that even small fires can temporarily change sediment processes in agroforestry catchments, with potential negative consequences for downstream water quality. [ABSTRACT FROM AUTHOR]

Studies of post-fire soil status in Mediterranean ecosystems are common; however, few have examined the effects of long-term forest management after a wildfire on physicochemical soil properties. Here, we analyzed differences in soil properties attributable to long-term post-fire management and assessed the sustainability of these management practices in relation to the soil properties. The study area is located in Ódena in the northeast region of the Iberian Peninsula consisted of the control forest (burned more than 30 years ago), low density forest (LD; burned in a wildfire in 1986 and managed in 2005) and high density forest (HD; burned in a wildfire in 1986 and no managed). For soils from each plot, we measured soil water repellency, aggregate stability, total nitrogen (TN), soil organic matter (SOM), inorganic carbon (IC), pH, electrical conductivity, extractable calcium, magnesium, sodium, potassium (K), phosphorus, aluminum (Al), manganese (Mn), iron (Fe), zinc, copper, boron, chrome, silicon and sulfur and calculated the ratios of C/N, Ca + Mg/(Na + K)1/2, Ca/Al and Ca/Mg. Significant differences were found in TN, IC, SOM, pH, K, Al, Mn, Fe and C/N ratio (p < 0.05). All soil properties were found to have largely recovered their pre-fire values. Soils were affected by the post-fire management practices implemented 20 years after the fire, as reflected in their respective physicochemical properties, so that soil properties at the control and LD sites are more similar today than those at the control and HD sites. Thus, sustainable forest management can overcome soil degradation in areas affected by wildfire in the medium- and long-term by improving soil properties. [ABSTRACT FROM AUTHOR]

• Large high severity patches and salvage logging hinder post-fire tree regeneration. • Distance from seed trees was the most important driver of Scots pine regeneration. • Potential positive effects of AN and importance of site selection for plantation. • Integrating micro-scale site selection can improve the efficiency of plantation. Changes in disturbance regimes triggered by land use and climate change can significantly alter forest ecosystems by modifying the distribution of some species and hindering post-disturbance tree regeneration dynamics. Applied nucleation (AN) could be a valuable active restoration approach for promoting natural recovery in forest ecosystems affected by stand-replacing disturbances as it improves seed availability and microsite conditions. The study aimed to investigate the potential of AN under different scenarios in a mountain forest ecosystem of the Northwestern Italian Alps dominated by Scots pine (Pinus sylvestris L.). The area was affected by a large stand-replacing fire in 2005 and post-fire salvage logging that amplified ecosystem degradation and dampened natural tree regeneration. We assessed the main drivers guiding natural post-fire natural recovery and identified suitable sites for tree regeneration through a machine learning correlative model (Bayesian Additive Regression Tree, BART). Specifically, we used several environmental predictors (e.g., topography, wind direction, and distance from seed trees) to model the occurrence of natural tree regeneration. We predicted the probability of tree regeneration presence at landscape scale under the current situation (fire followed by salvage logging) and a set of AN scenarios characterized by an increase in nuclei density, since distance from seed trees emerged as the most important driver for natural tree regeneration. Starting from the situation 16 years after the fire, we reclassified the prediction raster into a binary map of intervention priority (priority and non-priority patches), using the probability value that maximized the model accuracy (true skill statistic; TSS) as threshold. Patches with scarce pine regeneration were considered as high intervention priority sites for AN. These predictions made it possible to assess the most efficient active management scenario in terms of promoting forest recovery. The simulations showed the positive effects of AN on natural tree regeneration and the importance of site selection for plantations, proving that AN could be a promising post-fire management technique that can minimize human interventions and their associated economic and ecological costs. To our knowledge, this work is the first AN simulation in a temperate mountain ecosystem. The selection of favorable sites can be further improved by considering fine-scale characteristics through field experiments and cross-scale integration. [ABSTRACT FROM AUTHOR]

On 24 November 2016, extreme hot and dry weather led to more than 1000 fires in Israel. One of the largest fires (120 ha) occurred in the city of Haifa. The fire began on the slopes of the north-eastern part of the wildland–urban interface (WUI) and spread into the city, moving westward owing to strong wind gusts. Although private houses in open lands and villages in Israel have previously been affected by fires, this was the first 'urban fire' in Israel. In order to determine the best management strategy for the various types of burned areas, an 'identity card' was prepared for each area including main vegetation species and other points of interest. For urban forest areas, rehabilitation was planned according to topographic structure and anticipated soil erosion. In each reclaimed area, terraces were constructed using burned logs or local stones and inhibitors to mitigate soil erosion. After restoration, each urban forest underwent planting and renewal according to its geographic properties and location. An area of 120 ha inside Haifa and along the wildland–urban interface was damaged by fire in November 2016. Based on an 'identity card' formulated for each burnt site, the rehabilitation project aimed to minimise risk to population and infrastructure, provide essential ecological services to the residents and restore the fire damage. [ABSTRACT FROM AUTHOR]

Abstract In the Mediterranean Basin, changes in climate and fire regime (increased recurrence and severity) reduce ecosystem services after wildfires by increasing soil degradation and losses in plant diversity. Our study was a biological approach to relate soil properties to vegetation recovery and burn severity. We focused our study on the natural recovery of the soil-plant interphase in Pinus halepensis Mill. forests located in the SE of Iberian Peninsula, a semiarid climate. We included some chemical properties 3 years after fire (available phosphorus (P) and soil organic carbon (Corg), among others), and biological soil indicators 3 and 5 years after fire (i.e. basal soil respiration (BSR), microbial biomass carbon (Cmic), carbon mineralization coefficient (Cmineral), metabolic quotient (qCO 2) and microbial quotient (Cmic:Corg)). We analyzed the activity of three different enzymes: urease (UR), phosphatase (PHP) and β-glucosidase (GLU). The changes in most chemical properties were ephemeral, but P and Corg showed higher values in burned areas, and the highest were found for low-moderate severity. Plant recovery was the triggering factor for the recovery of Corg and biological soil function. Burn severity and time after fire influenced Cmic and the Cmic:Corg, which were higher for moderate-high severity 3 years later, but were below the unburned values 5 years after fire. The microbial activities of GLU and UR were recovered in burned areas 5 years after fire. The PHP values lowered according to higher burn severity and time after fire. The soil ecological trends obtained by a principal component analysis revealed a relationship linking GLU, BSR and qCO 2 that explained soil response to burn severity. PHP, Cmic and Cmic:Corg explained most of the variability related to time after fire. Our results provide insights into how burn severity, in Mediterranean fire-prone Aleppo pine stands, modulated the natural plant recovery linked to soil biochemical and microbiological response to fire. High burn severity limited natural vegetation recovery, and both reduced biological soil functionality. This knowledge can be implemented in post-fire planning to apply post-fire management (for mitigation and restoration) in which the "no intervention" tool should be contemplated. These findings provide information to be applied in adaptive forest management to improve the resilience of vulnerable ecosystems and to reduce burn severity in future fire events. Graphical abstract Image 1 Highlights • Plant recovery triggered soil organic carbon and biological soil functionality. • Available phosphorus and soil organic carbon were higher in burned areas. • Phosphatase lowered according to higher burn severity and time after fire. • Burn severity influenced β-glucosidase, soil respiration and metabolic quotient. • Time after fire influenced phosphatase-microbial biomass carbon-microbial quotient. [ABSTRACT FROM AUTHOR]

Mulches are highly effective in mitigating the risk of erosion generated after wildfires in fire-prone ecosystems. Despite being a technique commonly used, it remains completely unexplored how mulches interact with the positive effects of the emergent moss biocrust on the recovery and resilience of soils and their microbial communities. For this purpose, the effects of wood-based mulch were assayed on the soil stability and moisture improvement, the nutrient inputs, and the response of microbial biomass, activity, composition, and diversity. Soils were studied after one year of wood mulch application at two rates representing possible scenarios, "Rate 1" (65 % of soil cover), and "Rate 2" (100 % of cover), and "Control" soils without mulch. The biocrust development had a positive impact on soil aggregate stability and moisture retention before mulch application. However, one year after the mulch application the biocrust cover was drastically inhibited, especially at the highest rate of mulch. Independently of the biocrust presence, soils at Rate 1 registered a tendency to higher nitrogen content, available phosphorous, basal respiration, and microbial biomass carbon, suggesting an incipient recovery of soil conditions and soil functionality. However, the microbial community composition became more homogeneous and less diverse under the mulch presence (regardless of the application rate), and the positive effect of moss biocrust emergence on the microbial diversity was diluted after one year. The fungal community was particularly sensitive to the wood mulch presence, increasing in richness in response to fresh wood incorporation to soils, in particular saprotrophs and yeasts. The fungal and bacterial compositional shifts after the mulch application reveal an incipient wood decomposition stage, but the transitory loss in beta diversity after the moss biocrust suppression warns about the necessity of including the microbial diversity information into post-fire management planning. Studying the effects of forest management on the above and belowground soil communities is essential to understanding the resistance and resilience of semi-arid forests to the increasing intensity and severity of wildfires. • Wood mulch adversely affects biocrust-forming mosses development. • Wood mulch and biocrust presence stimulates the biochemical processes. • Positive effects of biocrust on microbial diversity were reduced after mulching. • Fungi are highly sensitive to shifts induced by wood mulch application. [ABSTRACT FROM AUTHOR]

Applying mulch to severely burned soils is common practice in fire-prone areas such as the NW Spain. Mulch that provides >80% cover can reduce post-fire soil erosion by up to 90%; however, this level of cover can sometimes be difficult to achieve in remote areas due to the logistic constraints. Although application of mulch strips is a possible alternative approach, there is no information available about the effectiveness of this technique. Such information is critical in protected areas where mulch application can modify the recovery of natural vegetation by altering the soil moisture regime. In this study, the effects of the application of 20 m wide straw mulch strips on soil erosion, soil moisture and vegetation recovery were assessed during the first year after a high-severity fire that occurred in September 2020 in two European dry-heathland areas. During the first year after the fire, the mean sediment yields in the untreated plots were 18.5 Mg ha−1 and 33.8 Mg ha−1, respectively at the Lobios and Vilariño study sites. Although the straw mulch strips reduced soil erosion by >70% on average, erosion rates remained high at both sites. Soil moisture contents in mulch-treated areas were significantly higher than in untreated areas during spring and summer. Mulching affected vegetation recovery in different ways, i.e., it had neutral to positive effects, depending on the study site. No alteration in species composition was observed in either of the sites as a result of treatment application. In summary, the reduction in soil erosion after the application of straw mulch strips covering 67% of burned soil under the conditions of the present study under the conditions of the present study reduced a 70–75% of soil erosion after a high-severity wildfire. • Straw mulch strips significantly reduced (70–75%) post-fire soil erosion. • Mulch application increases soil moisture relatively to the control in spring-summer. • The effects of mulch on vegetation cover ranged from neutral to positive. • Mulching did not affect plant species richness. [ABSTRACT FROM AUTHOR]

• Wildfires often modify the runoff-erosion response of hillslopes. • We evaluate erosion of burned volcanic soils using erosion plots and rill simulations. • The presence of volcanic soils and its weathering degree govern post-fire soil loss. • Burned volcanic soils showed lower erosion than soils developed on other lithologies. • Fire-affected mature volcanic soils showed less soil loss than young volcanic soils. Wildfires can dramatically modify the hydrologic and erosion response of ecosystems, increasing risks to population and assets downslope of fire affected hillslopes. This applies especially to volcanic areas in fire-prone regions which often exhibit steep terrain and high population densities. However, the effects of fire on key hydrologic and erosion parameters, which are critical for modelling runoff-erosion processes, predicting related post-fire risks and for selecting effective mitigation measures, have not been extensively assessed in this terrain type. Here we evaluate water erosion processes of two contrasting volcanic soils in recently burned forest areas of Tenerife (Canary Islands, Spain) at hillslope scale using erosion plots monitoring and rill erosion simulation experiments. The results show that both the lithology and the degree of weathering of the volcanic material govern the post-fire water erosion by concentrated flow (rill erosion experiments) and by the combination of interrill and rill erosion (erosion plots). Mature volcanic soils showed less susceptibility to erosion than weakly weathered volcanic soils and soils with non-volcanic lithologies. The results also show that the availability of easily detachable and transportable soil particles swiftly decreases after the fire, leading to the exhaustion of sediments and a decrease of the erosion rates with cumulative runoff events. These findings have direct implications for the modelling of runoff-erosion processes in volcanic terrain. [ABSTRACT FROM AUTHOR]

Allelopathy, the inhibition of neighbouring plant growth by certain plants, can be particularly useful if applied in a targeted way for weed management. So, this study aimed to assess and characterize the herbicidal activity of fresh and dried leaves from young Eucalyptus globulus Labill. trees applied as a soil amendment. For this, fresh and dried leaves (FL and DL, respectively) were incorporated into the soil at different concentrations (0, 1, 5, and 10% w/w), where Portulaca oleracea L. seeds were sown. After 5 weeks of exposure, results revealed that the soil incorporation of DL at 10% (w/w) presented the strongest herbicidal properties, inhibiting seed germination by 63% and inducing the loss of cell viability. To unravel the possible mode of action and the main targets at both cellular and subcellular levels, an in vitro experiment was performed. Purslane seeds were sown in a nutritive medium containing different dilutions of an aqueous extract prepared with dried eucalyptus leaves. After 5 days of exposure, germinated seedlings were processed for transmission electron microscopy and histological analyses as well as for reactive oxygen species (ROS) in vivo detection by confocal laser scanning microscopy. Results revealed that the allelochemical release from DL induced ROS overproduction, resulting in the loss of cell integrity and organization, which was characterized by damage to several cellular sub-structures, along with enhanced accumulation of lipid droplets. Overall, the incorporation of DL into the soil can represent a sustainable alternative to reduce synthetic herbicide application and subsequent environmental contamination. • Dried leaves of young E. globulus had the greatest pre-emergent herbicidal activity. • Allelochemicals caused redox disorders in purslane cotyledons and radicles. • Phytochemicals induced the loss of cell organization and integrity. • Dried leaf soil incorporation can represent an alternative for weed control. [ABSTRACT FROM AUTHOR]

• Organic matter and nutrients were different between treated and untreated soils. • Herbaceous plants were found only in UB and LEB sites. • Increases in OM and nitrogen are associated to more resprouting species. • Increases in pH and again OM are associated to more abundant tree and herbs. • The study indicates the most resilient plant species after post-fire restoration. The medium- and long-term studies about the effectiveness of post-fire management techniques on soil and plant ecology are scarce, although the effects of wildfire and subsequent management can be long lasting. This study has evaluated the changes in the main physico-chemical properties of soil and plant diversity six years after a wildfire and post-fire treatments using contour felled log debris (CFD) and log erosion barriers (LEB) in a Mediterranean pine forest in comparison to unburnt (UB), and burnt but untreated (BNA) sites. Soil texture and pH did not generally change after wildfire and treatments, while organic matter and nutrients were significantly different between the treated soils and the other sites. Herbaceous plants were found only in UB and LEB sites, the latter showing the lowest number of tree species. Shrubs were equally distributed among the four soil conditions. Resprouting and germinating plants increased in the treated sites compared to BNA area, which however showed a higher number of facultative resprouters. The analysis of relationships between soil properties and plant diversity showed that, when organic matter (CFD plots) and nitrogen (LEB plots) contents are noticeably higher compared to BNA soils, more resprouting species are detected. Moreover, significant increases in pH (UB and BNA plots) and organic matter (CFD plots) are associated to more abundant tree and herbaceous species. The study also indicates to forest managers the most resilient plant species after post-fire restoration several years after a wildfire under Mediterranean conditions. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) have become popular in recent years and are now used in a wide variety of applications. This is the logical result of certain technological developments that occurred over the last two decades, allowing UAVs to be equipped with different types of sensors that can provide high-resolution data at relatively low prices. However, despite the success and extraordinary results achieved by the use of UAVs, traditional remote sensing platforms such as satellites continue to develop as well. Nowadays, satellites use sophisticated sensors providing data with increasingly improving spatial, temporal and radiometric resolutions. This is the case for the Sentinel-2 observation mission from the Copernicus Programme, which systematically acquires optical imagery at high spatial resolutions, with a revisiting period of five days. It therefore makes sense to think that, in some applications, satellite data may be used instead of UAV data, with all the associated benefits (extended coverage without the need to visit the area). In this study, Sentinel-2 time series data performances were evaluated in comparison with high-resolution UAV-based data, in an area affected by a fire, in 2017. Given the 10-m resolution of Sentinel-2 images, different spatial resolutions of the UAV-based data (0.25, 5 and 10 m) were used and compared to determine their similarities. The achieved results demonstrate the effectiveness of satellite data for post-fire monitoring, even at a local scale, as more cost-effective than UAV data. The Sentinel-2 results present a similar behavior to the UAV-based data for assessing burned areas.

• The effects of mulching on ecosystem multifunctionality (EMF) have been little explored. • EMF increased from burned and untreated to mulched and to unburned sites. • No significant difference in EMF between the two mulches was found. • Mulching only partially dampened the impact of fire on EMF. • Almost all ecosystem functions were associated to soil or vegetation parameters. Straw and wood chips have been widely used as mulch materials to control post-fire erosion in burned forests. However, their effects on ecosystem multifunctionality (EMF) have been little explored. This information is essential to give forest managers insight about the effectiveness of these strategies for restoration of severely-burned forests. To fill this gap, this study has evaluated the short-term (one year after wildfire) changes in ecosystem properties (associated to soil characteristics), structure (linked to plant diversity), individual ecosystem functions, and EMF in a Mediterranean forest. This delicate ecosystem was burned by a wildfire and then mulched with straw or wood chips, and EMF in these conditions was compared to burned and untreated, and unburned sites. The results have shown that: (i) neither wildfire nor mulching significantly changed soil properties with the exception of pH; (ii) in contrast, ecosystem structure significantly declined in mulched plots due to wildfire, and mulching did not limit the alteration in species richness; (iii) among the analysed ecosystem functions, waste decomposition and nutrient cycling, which were significantly higher in unburned soils compared to burned sites, showed intermediate and similar values in mulched plots, while water cycle and wood production (the latter with the exception of unburned plots) were similar among all soil conditions, and climate regulation was significantly higher only in soils mulched with wood chips compared to burned sites; (iv) EMF increased from burned and untreated soils to unburned sites; (v) mulching was effective at limiting the reduction in EMF due to wildfire, but only partially dampened the impact of the fire. Moreover, the combined analysis of ecosystem properties, structure and functions, and EMF revealed that: (i) all functions, except water cycle, were associated to one or more soil or vegetation parameters; (ii) species community composition noticeably influenced several ecosystem functions, and, therefore, EMF; (iii) species richness is a key driver of wood production; (iv) pH, which was found as the most influential soil property on ecosystem functions and EMF, may be considered as an important ecological predictor of forest functions in basic soils of Mediterranean forests. This study may be of practical importance for policymakers and land managers about the most effective actions to preserve the ecosystem EMF in fragile ecosystems, such as the Mediterranean wildfire-affected forest. [ABSTRACT FROM AUTHOR]

With the effects of fire, weather and post-fire management on soil properties having been studied mostly individually, there is little understanding of the combined effects of wildfire, heavy storm and straw mulching. In this study, we evaluated the changes in soil properties following a high-severity fire, post-fire soil treatment using straw mulch, and a torrential storm in a forest stand in north-western Portugal. The main physicochemical properties of the soil were evaluated in different soil conditions: a) burnt and untreated, b) burnt and mulched areas, and c) unburnt sites on three survey dates 1) soon after wildfire, 2) after the rainstorm, and 3) one year after wildfire. We found that soil water repellency strongly increased ephemerally immediately after wildfire, decrease after the storm and disappeared after one year. Fire reduced the soil organic matter (by 50%, on average), total nitrogen (by 85–90%) and available phosphorous (by about 45%) at both the mulched and untreated sites, and this effect was not changed by the ensuing rainfall. In comparison to the unburnt sites, the pH increased in the burnt soils, and the electrical conductivity decreased. Finally, the dynamics of the major cations and minor elements were affected differently by the wildfire and rainfall under the different soil conditions. One year after the fire, the most notable changes compared to the unburnt soil were detected in magnesium, potassium and almost all the minor elements. Based on these findings, instructions were given to the land managers (aim to control soil hydrophobicity following wildfire, supply more soil organic matter to the soil to avoid a decline in soil fertility, and use alternative actions to straw mulching to control the soil chemistry) that were aimed at more effective post-fire management in severely burnt areas in Mediterranean forests. • Wildfire produces important changes on forest soils. • Torrential rainfall can damage soils affected by high severity fire. • Most soil changes produced by fire are ephemeral. • Post-fire straw mulching can avoid soil degradation. [ABSTRACT FROM AUTHOR]

• Red alder shows promise to aid in soil health post-fire. • Mixed stands with red alder demonstrated increased site index. • Douglas-fir site index continued to increase after alders died out. • Airborne lidar can be used to compare tree height when updated field data unavailable. A forester set up a large-scale, 1600-m fire-break trial with red alder (Alnus rubra Bong.) inter-planted between Douglas-fir (Pseudotsuga menziesii Mirb Franco) , after the extensive 1927 Yacolt Burn in the Columbia Gorge. This now 90-year-old trial demonstrates dramatic effects of alder on soils and growth of Douglas-fir; it also provides a timely lesson for foresters deciding what to do after recent similar fires in western Oregon and Washington. We used 2015 airborne lidar to re-examine the trial effects. Douglas-fir trees in stands mixed with alder (Strip) continue to grow taller than those in adjacent pure stands (Controls), even though almost all alder died out 30–40 years ago. Site index in Strip stand continues to increase relative to Controls, now averaging 30–40 % higher than Controls. Basal area ha−1 is 2.1, and stem biomass is 2.8 times higher in Strip than Control stands. Implications and future studies are discussed. Before planting wall-to-wall Douglas-fir, foresters responding to new fires in this region might contemplate alder interplanting and crop rotation for their likely positive effect on future revenue, wildlife, and carbon sequestration rates and storage above and belowground. [ABSTRACT FROM AUTHOR]