► Global change is predicted to worsen the fire problem. ► Fire-smart management is essential for forest sustainability in the Mediterranean. ► Management should focus on fire-severity mitigation and ...forest resiliency to fire.
Modified, more severe fire regimes are developing in the Mediterranean basin as a result of changes in land use and climate. Current fire management privileges fire suppression and tends to ignore land management issues, which may further accelerate the transition to a more fire-prone future and magnify the problem. Fire-smart management aims to control the fire regime by intervening on vegetation (fuel) to foster more fire-resistant (less flammable) and/or fire-resilient environments. Scientific knowledge supporting the creation and maintenance of fire-smart wildlands is critically reviewed, considering the landscape and the forest stand scales. Fuel management strategies (isolation, structural modification, and type conversion) are discussed in regards to their current and future potential to buffer the effects of global change on the extent and severity of fires. Uncertainty in the outcomes of fire-smart management arises mainly from insufficient understanding of the relative weights of fuel and weather-drought on the fire regime. Likewise, linkage between global change processes and the fire regime is not straightforward. Shrublands and, in general, open and dry vegetation types will prevail even more in future landscapes. Decrease in biomass will limit fire incidence over parts of the Mediterranean. However, the fire regime will be largely driven by weather, advising concentration of fuel management efforts in wildland–urban interfaces and in forests and their vicinity; decrease of landscape fire severity rather than area burned as the objective; prescribed burning as the treatment of choice, except in the wildland-urban interface; and focus on forest types that are fire-resilient irrespective of flammability.
Prescribed burning is a technically demanding and usually highly scrutinized and debated practice. Barriers of various natures have constrained the development of prescribed burning in forests (PUB) ...in southern Europe, with insufficient research and outreach among the contributing factors. This paper synthesizes PUB knowledge in the region and identifies research needs. PUB research in the western Mediterranean basin was fostered by international cooperative projects that studied the ecological and management ramifications of low-intensity burning for fire hazard mitigation. Effects of PUB on soil and vegetation are minor and short-lived and regulated through forest floor moisture content, fire intensity, tree resistance to fire, and ignition patterns. Generic burn prescriptions are available and specific burn windows targeting site-specific burn objectives can be developed with the existing software tools. However, the need to increase the depth and breadth of PUB research is apparent. Current knowledge is based upon pine forests, particularly Pinus pinaster, as past research has overlooked hardwoods; was obtained across a limited number of research teams and study sites; and essentially reflects short-term treatments. Fuel consumption by PUB effectively decreases fire potential, but post-treatment fuel dynamics and effects on wildfire spread and severity warrant further study. Future work should devote more attention to the socioeconomic, biodiversity and carbon storage implications of PUB and should expand to encompass cumulative effects and the whole PUB regime and its variation; long-term experiments and monitored management programs are crucial to this end.
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•Knowledge gaps may restrain prescribed underburning development in southern Europe.•Current burn prescriptions guarantee that impacts are minor and fade rapidly.•Socioeconomy, biodiversity, fire hazard and carbon implications merit further study.•Research should evolve from the burn event to the burn regime.•Long-term studies and monitoring of management practices are needed.
Cellular-mediated inflammatory response, lymphocytes, neutrophils, and monocytes are increasingly being recognised as having an important role in tumorigenesis and carcinogenesis. In this context, ...studies have suggested that the neutrophil-to-lymphocyte ratio (NLR) can be used as an independent prognostic factor in a variety of cancers. Particularly in breast cancer, several studies have shown that a high NLR is associated with shorter survival. Because the NLR can be easily determined from the full blood count, it could potentially provide a simple and inexpensive test cancer prognosis. This review addresses the possibilities and limitations of using the NLR as a clinical tool for risk stratification helpful for individual treatment of breast cancer patients. The potential underlying phenomena and some perspectives are discussed.
Forest fire management relies on fire danger rating to optimize its suite of activities. Limiting fire size is the fire management target whenever minimizing burned area is the primary goal, such as ...in the Mediterranean Basin. Within the region, wildfire incidence is especially acute in Portugal, a country where fire-influencing anthropogenic and landscape features vary markedly within a relatively small area. This study establishes daily fire weather thresholds associated to transitions to increasingly larger fires for individual Portuguese regions (2001–2011 period), using the national wildfire and Canadian fire weather index (FWI) databases and logistic regression. FWI thresholds variation in relation to population density, topography, land cover, and net primary production (NPP) metrics is examined through regression and cluster analysis. Larger fires occur under increasingly higher fire danger. Resistance to fire spread (the fire-size FWI thresholds) varies regionally following biophysical gradients, and decreases under more complex topography and when NPP and occupation by flammable forest or by shrubland increase. Three main clusters synthesize these relationships and roughly coincide with the western north-central, eastern north-central and southern parts of the country. Quantification of fire-weather relationships can be improved through additional variables and analysis at other spatial scales.
Eucalypts, especially blue gum (Eucalyptus globulus), have been extensively planted in Portugal and nowadays dominate most of its forest landscapes. Large-scale forestation programs can intensify ...fire activity, and blue gum plantations are often viewed as highly flammable due to the nature and structure of the fuel complex. The role of eucalypt plantations in the fire regime of Mediterranean climate regions is increasingly debated following the recent catastrophic wildfires in Portugal and elsewhere. In this study we examined the effects of eucalypt forestation on burned area (BA), fire size, and fire severity in Portugal. This was based on fire and vegetation mapping and statistics, fire weather data, satellite imagery, and national forest inventory data. Eucalypt BA comprised an average of 12.5% of total BA (1980–2017) and did not increase over time and with eucalypt expansion. Eucalypt metrics did not explain interannual BA variability after accounting for the effects of other variables. Forest fires started within eucalypt stands were the least likely to become large, and large fire size was irresponsive to forest composition. Likewise, forest type was a generally minor influence in mega-fire severity and accounted for just 1.4–8.6% of surface fuel-hazard metrics variation. In general, large-scale conversion of maritime pine to eucalypt stands (1970–2015) implied lower fuel accumulation. Fire activity results are consistent with fuel hazard results and express trade-offs between short-rotation forestry and fire behaviour in blue gum stands, with high spotting potential versus modest crown fire likelihood. We found no support for the contention of a modified fire regime as a result of eucalypt forestation in Portugal, but the rising undermanaged and abandoned blue gum estate, especially after large-fire seasons, is a concern for the future. However, it remains to be determined whether post-fire eucalypt regrowth is a higher fire threat than native vegetation in the same context.
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•Eucalypt expansion did not increase burned area in Portugal.•Fire size independent of forest composition•Slight decrease of mega-fire severity in eucalypt stands•Forest type is a minor influence on fuel hazard.•Fire activity reflects trade-offs between short-rotation forestry and fire behaviour.
Wildfire is a common phenomenon in Mediterranean countries but the 2022 fire season has been extreme in southwest Europe (Portugal, Spain and France). Here we provide a preliminary but comprehensive ...analysis of 2022's wildfire season in southwest Europe. Burned area has exceeded the 2001–2021 median by a factor of 52 in some regions and large wildfires (>500 ha) started to occur in June–July, earlier than the traditional fire season. These anomalies were associated with record-breaking values of fuel dryness, atmospheric water demand and pyrometeorological conditions. Live fuel moisture content was below the historical minima for almost 50 % of the season in some regions. A few large wildfires were responsible for 82 % of the burned area and, in turn, 47 % of the area burned occurred in protected areas. Shrublands, transitional woodlands and conifer forests (but not eucalypt plantations) were the land cover types most affected by extreme fires. As climate change intensifies, we can expect such fire seasons to become the new normal in large parts of the continent, potentially leading to major negative impacts on rural economies. These results highlight the need for landscape level fuel management also in protected areas, to avoid fire-induced biodiversity losses and landscape scale degradation. Our results have important policy implications and indicate that fire prevention should be explicitly addressed within continental forest legislation and strategies.
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•The 2022 fire season in SW Europe reached record burned area in some regions.•Early fire onset and early occurrence of large fires characterized the season.•pt?>Record-breaking fuel aridity and pyrometeorology associated with fire activity.•Nearly half of the area burned in large fires occurred in protected areas.•2022 may be a spyglass into the “new normal” for fire activity under global warming.
Characterizing the fire regime in regions prone to extreme wildfire behavior is essential for providing comprehensive insights on potential ecosystem response to fire disturbance in the context of ...global change. We aimed to disentangle the linkage between contemporary damage-related attributes of wildfires as shaped by the environmental controls of fire behavior across mainland Portugal. We selected large wildfires (≥100 ha, n = 292) that occurred during the 2015–2018 period, covering the full spectrum of large fire-size variation. Ward's hierarchical clustering on principal components was used to identify homogeneous wildfire contexts at landscape scale on the basis of fire size, proportion of high fire severity, and fire severity variability, and their bottom-up (pre-fire fuel type fraction, topography) and top-down (fire weather) controls. Piecewise Structural Equation Modeling was used to disentangle the direct and indirect relationships between fire characteristics and fire behavior drivers. Cluster analysis evidenced severe and large wildfires in the central region of Portugal displaying consistent fire severity patterns. Thus, we found a positive relationship between fire size and proportion of high fire severity, which was mediated by distinct fire behavior drivers involving direct and indirect pathways. A high fraction of conifer forest within wildfire perimeters and extreme fire weather were primarily responsible for those interactions. In the context of global change, our results suggest that pre-fire fuel management should be targeted at expanding the fire weather settings in which fire control is feasible and promote less flammable and more resilient forest types.
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•Extreme wildfire clusters are mainly concentrated in the central region of Portugal.•We evidenced a covariation between fire size, fire severity, and severity variability.•Complex pathways shape the relationships between the attributes of extreme wildfires.•Fire weather controls fire severity indirectly through its direct effect on fire size.
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