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1.
Environ Monit Assess ; 193(10): 684, 2021 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-34599681

RESUMEN

Fires can pose a threat to forest ecosystems when those ecosystems are not fire-adapted or when forest community conditions make them vulnerable to wildfires. Thus, investigating fire-prone environmental conditions is urgently needed to create action plans that preserve these ecosystems. In this sense, climate variables can determine the environmental conditions favorable for forest fires. Our study confirms that vapor pressure deficit (VPD) is an essential climate indicator for forest fires, as it is related to maximum temperatures and low humidity, representing the stress conditions for vegetation prone to fires. This study explores the extent to which ENSO phases can modulate climatic conditions that lead to high VPD over Guanajuato, a semi-arid region in central Mexico, during the dry season (March-April-May). Using fire occurrence data from MODIS (2000-2019) and Landsat 5 (1998-1999), we developed a climatic probability model for the occurrence of forest fires using VPD estimated from ERA5 reanalysis for each ENSO phase. We found that VPD and the occurrence of forest fires were higher during El Niño than under Neutral and La Niña years, with a higher risk of forest fire occurrence in Guanajuato's southern region. This study concludes that it is necessary to implement regional and local fire management plans, especially where the largest number of natural protected areas is located.


Asunto(s)
Incendios , Incendios Forestales , Ecosistema , Monitoreo del Ambiente , Bosques , Probabilidad
2.
Sensors (Basel) ; 21(19)2021 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-34640837

RESUMEN

The territory of the Republic of Serbia is vulnerable to various natural disasters, among which forest fires stand out. In relation with climate changes, the number of forest fires in Serbia has been increasing from year to year. Protected natural areas are especially endangered by wildfires. For Nature Park Golija, as the second largest in Serbia, with an area of 75,183 ha, and with MaB Reserve Golija-Studenica on part of its territory (53,804 ha), more attention should be paid in terms of forest fire mitigation. GIS and multi-criteria decision analysis are indispensable when it comes to spatial analysis for the purpose of natural disaster risk management. Index-based and fuzzy AHP methods were used, together with TOPSIS method for forest fire susceptibility zonation. Very high and high forest fire susceptibility zone were recorded on 26.85% (Forest Fire Susceptibility Index) and 25.75% (fuzzy AHP). The additional support for forest fire prevention is realized through an additional Internet of Thing (IoT)-based sensor network that enables the continuous collection of local meteorological and environmental data, which enables low-cost and reliable real-time fire risk assessment and detection and the improved long-term and short-term forest fire susceptibility assessment. Obtained results can be applied for adequate forest fire risk management, improvement of the monitoring, and early warning systems in the Republic of Serbia, but are also important for relevant authorities at national, regional, and local level, which will be able to coordinate and intervene in a case of emergency events.


Asunto(s)
Incendios , Incendios Forestales , Bosques , Sistemas de Información Geográfica , Humanos , Serbia
3.
Artículo en Inglés | MEDLINE | ID: mdl-34639829

RESUMEN

The spatial and temporal behavior of the occurrence of forest fires in Chile was evaluated in the presence of COVID-19 and mobility restrictions. The fire period from 2015-2016 to 2020-2021 was considered and statistics on mobility restrictions were granted by the Government of Chile. The analysis was developed at different scales of geographic perception. At the national and regional levels, the global behavior of the occurrence was determined, and later at the communal level, the political territorial unit, to determine internal variations attributable to the mobility dynamics in the quarantine period. In the process, the meteorological background of the fire activity was also considered. The results indicate that it is possible to rule out a meteorological effect, based on the variation of the moisture content of fine fuel. There was also no statistical association between the humidity of the fuel and the variation in the occurrence of fires. It is concluded that the communes that presented the greatest mobility of people before the pandemic were those that obtained the greatest reduction in fires. The variation in mobility, the product of restriction measures, is a statistical predictor of the increase or decrease in fires.


Asunto(s)
COVID-19 , Incendios , Incendios Forestales , Chile/epidemiología , Bosques , Humanos , Pandemias , SARS-CoV-2
4.
Nature ; 597(7876): 366-369, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34526704

RESUMEN

Southeast Australia experienced intensive and geographically extensive wildfires during the 2019-2020 summer season1,2. The fires released substantial amounts of carbon dioxide into the atmosphere3. However, existing emission estimates based on fire inventories are uncertain4, and vary by up to a factor of four for this event. Here we constrain emission estimates with the help of satellite observations of carbon monoxide5, an analytical Bayesian inversion6 and observed ratios between emitted carbon dioxide and carbon monoxide7. We estimate emissions of carbon dioxide to be 715 teragrams (range 517-867) from November 2019 to January 2020. This is more than twice the estimate derived by five different fire inventories8-12, and broadly consistent with estimates based on a bottom-up bootstrap analysis of this fire episode13. Although fires occur regularly in the savannas in northern Australia, the recent episodes were extremely large in scale and intensity, burning unusually large areas of eucalyptus forest in the southeast13. The fires were driven partly by climate change14,15, making better-constrained emission estimates particularly important. This is because the build-up of atmospheric carbon dioxide may become increasingly dependent on fire-driven climate-carbon feedbacks, as highlighted by this event16.


Asunto(s)
Dióxido de Carbono/análisis , Imágenes Satelitales , Incendios Forestales/estadística & datos numéricos , Atmósfera/química , Australia , Teorema de Bayes , Monóxido de Carbono/análisis , Cambio Climático , Eucalyptus , Bosques , Pradera , Incertidumbre
5.
J Environ Manage ; 300: 113733, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34547572

RESUMEN

A range of approaches have been developed to support natural resource management. One such approach, stakeholder analysis, involves the use of a range of tools to identify and assess stakeholder interests and influence. Comprehensive empirical stakeholder analysis, however, can be time consuming and resource intensive. Approaches therefore frequently rely on the researcher's personal interpretation rather than empirical analysis. To address this limitation, a web content-based method (WCM) is proposed. Innovative and user-friendly, this empirical method comprises stakeholder information and the use of keywords in a content analysis of preselected stakeholder webpages, demonstrated here, through UK forestry, as an illustrative example. In this study, the application of WCM provides a comprehensive overview of the multitude of stakeholders in UK forestry and in the various goods and services they provide: Stakeholders' primary interests were in the provisioning services of timber and fuel wood; the cultural services of education and recreation; and to a lesser extent, the regulating services of climate and water regulation. While not without limitations, this systematic method provides an effective tool to support researchers, industry, and non-governmental organisations in different fields and countries, to undertake stakeholder analysis, especially in the case of small-scale studies in complex contexts and where resources are limited.


Asunto(s)
Conservación de los Recursos Naturales , Agricultura Forestal , Recursos Naturales , Madera
6.
J Environ Manage ; 299: 113606, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34523540

RESUMEN

Forest certification has emerged as a voluntary, market-driven tool for sustainable forest management (SFM). Its legitimacy depends on its ability to achieve its objectives and to retain the support of stakeholders such as NGOs and the companies that adopt it. This study presents a novel approach for assessing the contributions of forest certification to biodiversity conservation, based on Forest Stewardship Council (FSC) certification in four northern European countries (Finland, Sweden, Estonia, Latvia). In each case, national FSC certification requirements related to specific biodiversity targets were compared with requirements in national legislation. Nearly 80% of the assessed certification requirements were more prescriptive than the national legislation. One-third of these requirements (3-8 per country) were assessed to have a positive contribution to biodiversity conservation, whereas four requirements (up to 2 per country) were assessed to have a low positive contribution. FSC requirements to protect Woodland Key Habitats were identified as having a positive contribution in all four countries, whereas requirements regarding live tree retention in harvests and preserving dead wood had a positive contribution in three countries each. Despite often prescribing similar measures, the other requirements with positive contributions varied between countries depending on the national legislative baseline. The remaining requirements could not be assessed through expert evaluation, indicating the need for additional empirical research to evaluate how the normative requirements translate to impacts in the field, and how the national context may affect their implementation. The approach is globally applicable, repeatable, and provides a basis for designing systematic empirical assessments of the certification impact.


Asunto(s)
Conservación de los Recursos Naturales , Agricultura Forestal , Biodiversidad , Certificación , Bosques
7.
J Environ Manage ; 300: 113741, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34562820

RESUMEN

Lowland oak forests host high biodiversity throughout Europe, and to maintain their high biodiversity potential we need to understand how current silviculture practices influence these ecosystems. The most common harvest approach in oak woodlands remains clear-cutting followed by site preparation for reforestation. The site preparation can vary in intensity and possibly affect forest biodiversity in various ways. We studied the impact of site preparation intensity on ground-dwelling arthropod predators and detritivores in commercial oak woodlands. The intensive management included mechanical site preparation with soil milling, stump removal, and herbicide application. The extensive management consisted of natural succession after reforestation with only such slight disturbances as regular hand-provided mowing of vegetation. We recorded 120 spider species, 92 species of ground beetles, 10 species of centipedes, 17 species of millipedes, and 7 species of woodlice, including a relatively large number of threatened species. We found that intensive post-logging management strongly homogenized the habitat structure, and this led to low multi-trophic taxonomic and functional diversity in comparison to that under extensive management. At sites with extensive management, there was not only high functional diversity but also high functional redundancy. Species of conservation concern almost vanished from clearings under intensive management. The high multi-trophic diversity and functional redundancy indicate that extensive site preparation may enhance ecosystem multi-functionality, including primary productivity and ecosystem resilience. Extensive post-harvest management is therefore strongly preferable, and it is also economically more feasible. Intensive post-harvest management should be prohibited in lowland forests within transition zones to localities under nature protection or in natural oak forests.


Asunto(s)
Escarabajos , Quercus , Animales , Biodiversidad , Ecosistema , Agricultura Forestal , Bosques , Árboles
9.
An Acad Bras Cienc ; 93(suppl 3): e20190726, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34431861

RESUMEN

Fire risk mapping is a basic planning and protection element. This study presents the application of fuzzy logic in a geographic information system (GIS) as an alternative multi-criteria analysis for determining the areas of highest risk of forest fire in natural forest remnants in the Brazil. In the decision-making process, a set of factors that are relevant to fire safety were identified in the study area. For each input variable chosen for the model, a pertinence function was defined that best described its influence on fire risk. Subsequently, the variables were combined for the presentation of the final fire risk map. Concluded in the study that an increased risk of fire occurs at the wildland - urban interface. A strong relationship was observed between the fire ignition points and proximity to roads and urban areas. The proposed model was efficient to integrate the variables and determine areas of greatest risk.


Asunto(s)
Sistemas de Información Geográfica , Incendios Forestales , Brasil , Bosques , Lógica Difusa
10.
Artículo en Inglés | MEDLINE | ID: mdl-34444135

RESUMEN

Wildfires represent a natural phenomenon with detrimental effects on natural resources and human health. A better knowledge, perception, and awareness of wildfire risk may help communities at risk of exposure to prevent future events and safeguard their own lives. The aim of this study is to explore differences between individuals with and without previous wildfire experience, in terms of (1) subjective and advanced wildfire knowledge, (2) self-reported perceptions, (3) level of information, (4) self-protection measures, and (5) importance of community involvement. As a second step, we investigated differences in the same variables, focusing more deeply on a group of individuals with previous wildfire experience, classifying them according to fire-related employment (fire-related workers vs. non-workers) and wildland-urban interface (WUI) proximity (WUI residents vs. non-WUI residents). The Kruskal-Wallis test was applied to establish differences between the pairs of subsamples. Our results partially confirmed our hypothesis, that direct experience leads individuals to have a greater preparedness on the topic of wildfires. Perception of knowledge is reflected only at a shallow level of expertise, and, therefore, no relevant within-group differences related to fire-related employment or to WUI proximity were detected. Moreover, available information was perceived to be insufficient, thus we report a strong need for developing effective communication to high-risk groups, such as homeowners and fire-related workers.


Asunto(s)
Incendios , Incendios Forestales , Participación de la Comunidad , Conservación de los Recursos Naturales , Humanos , Percepción
11.
J Environ Manage ; 296: 113343, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34351293

RESUMEN

Fire is one of the main disturbances of tropical forests. Understanding the spatial and temporal dynamics of forest fires is of fundamental importance for the conservation of tropical forests. We used a frequency ratio model to identify those areas most susceptible to forest fires in the Central Corridor of the Atlantic Forest, from 2001 to 2019. We used data from the burned area of MODIS MCD64A1 to create the dependent variable grouped as climatic, topographic and human and landscape variables. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to assess the model's performance. Land use and relief orientation were the most and least important variables in the model, respectively. The model showed good AUC values, ranging from 0.72 to 0.96, with an average of 0.81 for the study period. The average distribution of susceptibility classes was low (19.62 %), medium (24.45 %) and high (20.55 %). The northwestern region of the CAFC was the one that presented the greatest susceptibility to the occurrence of forest fires. The frequency ratio proved to be a good model for mapping areas susceptible to forest fires in an area of the Atlantic Forest.


Asunto(s)
Incendios , Incendios Forestales , Bosques , Humanos , Árboles
13.
J Environ Manage ; 296: 113122, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34265666

RESUMEN

Although forest fires are indispensable for some ecosystems, they can have profound economic, environmental, and social implications, especially when they reach high intensities. There are two crucial factors in fighting forest fires: the availability of water resources and the service network. The objective of this study was to propose an alternative methodology for allocating water reservoirs to fight forest fires. The research was divided into three stages: zoning of fire risk, delimitation of viable areas for the implementation of water reservoirs, and determining strategic locations for reservoir allocation. The variables analyzed were land use and occupation, provision of watercourses, relief orientation, slope, proximity to roads, temperature, and precipitation. Fuzzy logic, Euclidean distance, and network analysis were used as the modeling techniques. Scenarios with all risk classes and only the high- and very high-risk classes were analyzed. A total of 66% of the area was represented by the low- and moderate-risk fire classes and 53.16% had a low potential for reservoir allocation, influenced by the low availability of water resources in the area. The proposed model efficiently allocated the water collection points in the different scenarios, and allowed the determination of the areas most susceptible to the occurrence of forest fires and the optimal locations for the installation of reservoirs, with the allocation of 21 water reservoirs to attend the areas of high- and very high-risk of occurrence of fires at a safe speed (40 km h-1) and 47 reservoirs to meet all risk classes at the same speed. The proposed methodology is feasible, applicable, and adjustable and can be implemented in other conservation units and areas of economic interest.


Asunto(s)
Incendios , Incendios Forestales , Conservación de los Recursos Naturales , Ecosistema , Bosques , Árboles , Agua
14.
J Environ Manage ; 293: 112825, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34289588

RESUMEN

Recent extreme wildfire seasons in the United States (US) have rekindled policy debates about the underlying drivers and potential role forest management can play in reducing fuels and future wildfire. Most US western national forests face a substantial backlog of treatments and manifold management issues related to wildfire, forest health, and wildfire protection and constitute the major part of the wildfire problem. However, the precise schedule and detailed assessments that map the type and amount of treatments needed, as well as the associated cost are rarely assessed. We simulated restoration trajectories on the US fire prone Umatilla National Forest that faces complex management challenges related to wildfire and forest resiliency. The treatments were targeted to specific ecological conditions based on a decision tree developed in consultation with specialists. Planning areas were then prioritized based on fire protection of the wildland-urban interface (WUI), forest products, and stand resiliency. The results revealed a backlog of 211,893 ha, that when treated would generate $320 million in revenue from forest products, and cover 80% of the forest. The treatment area estimate was more than double prior estimates based on ecological departure from historic condition. Financial sensitivity analysis showed that high priority fuel treatments were revenue positive on 22% of the planning areas. The study established a restoration blueprint in terms of amount, location, and treatment type to support funding requests to the agency and schedule internal and external capacity to complete the work. The work also contributes to ongoing collaborative restoration planning to help stakeholders understand the opportunity cost of specific restoration objectives. The case study and framework can be widely extrapolated to the national forests in the western US to improve financial evaluation of forest and fuel management and estimate future management inputs. This work represents a rare instance of a bottom-up spatially explicit assessment of a restoration backlog, and prioritization of planning areas to reduce that backlog on a US national forest.


Asunto(s)
Bosques , Incendios Forestales , Estaciones del Año , Estados Unidos
15.
Sensors (Basel) ; 21(12)2021 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-34207736

RESUMEN

Wildfires have affected global forests and the Mediterranean area with increasing recurrency and intensity in the last years, with climate change resulting in reduced precipitations and higher temperatures. To assess the impact of wildfires on the environment, burned area mapping has become progressively more relevant. Initially carried out via field sketches, the advent of satellite remote sensing opened new possibilities, reducing the cost uncertainty and safety of the previous techniques. In the present study an experimental methodology was adopted to test the potential of advanced remote sensing techniques such as multispectral Sentinel-2, PRISMA hyperspectral satellite, and UAV (unmanned aerial vehicle) remotely-sensed data for the multitemporal mapping of burned areas by soil-vegetation recovery analysis in two test sites in Portugal and Italy. In case study one, innovative multiplatform data classification was performed with the correlation between Sentinel-2 RBR (relativized burn ratio) fire severity classes and the scene hyperspectral signature, performed with a pixel-by-pixel comparison leading to a converging classification. In the adopted methodology, RBR burned area analysis and vegetation recovery was tested for accordance with biophysical vegetation parameters (LAI, fCover, and fAPAR). In case study two, a UAV-sensed NDVI index was adopted for high-resolution mapping data collection. At a large scale, the Sentinel-2 RBR index proved to be efficient for burned area analysis, from both fire severity and vegetation recovery phenomena perspectives. Despite the elapsed time between the event and the acquisition, PRISMA hyperspectral converging classification based on Sentinel-2 was able to detect and discriminate different spectral signatures corresponding to different fire severity classes. At a slope scale, the UAV platform proved to be an effective tool for mapping and characterizing the burned area, giving clear advantage with respect to filed GPS mapping. Results highlighted that UAV platforms, if equipped with a hyperspectral sensor and used in a synergistic approach with PRISMA, would create a useful tool for satellite acquired data scene classification, allowing for the acquisition of a ground truth.


Asunto(s)
Incendios , Incendios Forestales , Bosques , Italia , Portugal
16.
Commun Biol ; 4(1): 869, 2021 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-34267317

RESUMEN

The tropical forests of Central America serve a pivotal role as biodiversity hotspots and provide ecosystem services securing human livelihood. However, climate change is expected to affect the species composition of forest ecosystems, lead to forest type transitions and trigger irrecoverable losses of habitat and biodiversity. Here, we investigate potential impacts of climate change on the environmental suitability of main plant functional types (PFTs) across Central America. Using a large database of occurrence records and physiological data, we classify tree species into trait-based groups and project their suitability under three representative concentration pathways (RCPs 2.6, 4.5 and 8.5) with an ensemble of state-of-the-art correlative modelling methods. Our results forecast transitions from wet towards generalist or dry forest PFTs for large parts of the study region. Moreover, suitable area for wet-adapted PFTs is projected to latitudinally diverge and lose connectivity, while expected upslope shifts of montane species point to high risks of mountaintop extinction. These findings underline the urgent need to safeguard the connectivity of habitats through biological corridors and extend protected areas in the identified transition hotspots.


Asunto(s)
Cambio Climático , Ecosistema , Agricultura Forestal/estadística & datos numéricos , Plantas/metabolismo , Árboles/metabolismo , Animales , Biodiversidad , América Central , Conservación de los Recursos Naturales/métodos , Conservación de los Recursos Naturales/estadística & datos numéricos , Conservación de los Recursos Naturales/tendencias , Agricultura Forestal/métodos , Agricultura Forestal/tendencias , Geografía , Humanos , Modelos Teóricos , Plantas/clasificación , Dinámica Poblacional , Árboles/clasificación , Clima Tropical
17.
Glob Chang Biol ; 27(18): 4339-4351, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34213047

RESUMEN

Changing climate and disturbance regimes are increasingly challenging the resilience of forest ecosystems around the globe. A powerful indicator for the loss of resilience is regeneration failure, that is, the inability of the prevailing tree species to regenerate after disturbance. Regeneration failure can result from the interplay among disturbance changes (e.g., larger and more frequent fires), altered climate conditions (e.g., increased drought), and functional traits (e.g., method of seed dispersal). This complexity makes projections of regeneration failure challenging. Here we applied a novel simulation approach assimilating data-driven fire projections with vegetation responses from process modeling by means of deep neural networks. We (i) quantified the future probability of regeneration failure; (ii) identified spatial hotspots of regeneration failure; and (iii) assessed how current forest types differ in their ability to regenerate under future climate and fire. We focused on the Greater Yellowstone Ecosystem (2.9 × 106  ha of forest) in the Rocky Mountains of the USA, which has experienced large wildfires in the past and is expected to undergo drastic changes in climate and fire in the future. We simulated four climate scenarios until 2100 at a fine spatial grain (100 m). Both wildfire activity and unstocked forest area increased substantially throughout the 21st century in all simulated scenarios. By 2100, between 28% and 59% of the forested area failed to regenerate, indicating considerable loss of resilience. Areas disproportionally at risk occurred where fires are not constrained by topography and in valleys aligned with predominant winds. High-elevation forest types not adapted to fire (i.e., Picea engelmannii-Abies lasiocarpa as well as non-serotinous Pinus contorta var. latifolia forests) were especially vulnerable to regeneration failure. We conclude that changing climate and fire could exceed the resilience of forests in a substantial portion of Greater Yellowstone, with profound implications for carbon, biodiversity, and recreation.


Asunto(s)
Pinus , Incendios Forestales , Clima , Cambio Climático , Ecosistema , Bosques
18.
J Environ Manage ; 296: 113188, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34225045

RESUMEN

Ecosystem service (ES) mapping has been developed with the aim of supporting ecosystem management, but ES maps often lack information about uncertainty and risk, which is essential for decision-making. In this paper, we use a risk-based approach to map ES in mountain forests, which are experiencing an increasing rate of natural disturbances, such as windthrow, bark beetle outbreaks, and forest fires. These disturbances affect the capacity of forests to provide essential ecosystem services, such as protection from natural hazards, wood production, and carbon sequestration, thus posing a challenge for forest management. At the same time, disturbances may also have a positive effect on certain services, e.g. by improving habitats for species that rely on dead wood. We integrate forests' susceptibility to natural disturbances into probabilistic Bayesian Network models of a set of ES (avalanche protection, carbon sequestration, recreation, habitats, and wood production), which combine information from remote sensing, social media and in-situ data, existing process-based models, and local expert knowledge. We use these models to map the level of the services and the associated uncertainties under scenarios with and without natural disturbances in two case study areas in the Swiss Alps. We use clustering to identify bundles of risk to ES, and compare the patterns of risk between the non-protected area of Davos and the strictly protected area of the Swiss National park with its surroundings. The spatially heterogeneous pattern of risk to ES reflects topographic variability and the forest characteristics that drive disturbance susceptibility, but also the demand for ecosystem services. In the landscape of Davos, the most relevant risks to ES are related to decreases in the protection against avalanches and carbon sequestration, as well as some risk to wood production and recreation. In the strictly protected Swiss National Park, the overall level of ES risk is lower, with an increase in habitat quality under the disturbance scenario. This risk-based approach can help identify stands with high levels of ES that are particularly susceptible to disturbances, as well as forests with a more stable ES provision, which can help define priorities in forest management planning.


Asunto(s)
Ecosistema , Incendios Forestales , Teorema de Bayes , Secuestro de Carbono , Conservación de los Recursos Naturales , Bosques , Humanos
20.
Sci Total Environ ; 797: 149104, 2021 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-34303242

RESUMEN

Fuel moisture limits the availability of fuel to wildfires in many forest areas worldwide, but the effects of climate change on moisture constraints remain largely unknown. Here we addressed how climate affects fuel moisture in pine stands from Catalonia, NE Spain, and the potential effects of increasing climate aridity on burned area in the Pyrenees, a mesic mountainous area where fire is currently rare. We first quantified variation in fuel moisture in six sites distributed across an altitudinal gradient where the long-term mean annual temperature and precipitation vary by 6-15 °C and 395-933 mm, respectively. We observed significant spatial variation in live (78-162%) and dead (10-15%) fuel moisture across sites. The pattern of variation was negatively linked (r = |0.6|-|0.9|) to increases in vapor pressure deficit (VPD) and in the Aridity Index. Using seasonal fire records over 2006-2020, we observed that summer burned area in the Mediterranean forests of Northeast Spain and Southern France was strongly dependent on VPD (r = 0.93), the major driver (and predictor) of dead fuel moisture content (DFMC) at our sites. Based on the difference between VPD thresholds associated with large wildfire seasons in the Mediterranean (3.6 kPa) and the maximum VPD observed in surrounding Pyrenean mountains (3.1 kPa), we quantified the "safety margin" for Pyrenean forests (difference between actual VPD and that associated with large wildfires) at 0.5 kPa. The effects of live fuel moisture content (LFMC) on burned area were not significant under current conditions, a situation that may change with projected increases in climate aridity. Overall, our results indicate that DFMC in currently fire-free areas in Europe, like the Pyrenees, with vast amounts of fuel in many forest stands, may reach critical dryness thresholds beyond the safety margin and experience large wildfires after only mild increases in VPD, although LFMC can modulate the response.


Asunto(s)
Incendios , Incendios Forestales , Cambio Climático , Ecosistema , Bosques
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