Estimation of moisture in live fuels in the mediterranean: Linear regressions and random forests.

The live fuel moisture content is an important factor in estimating the risk of forest fires and their rate of spread. However, due to a lack of research, the FMC values in the Mediterranean region of Andalusia, Spain, must be obtained by sample collection. This study is therefore the first to provide tools for estimating the moisture content of the most widespread plant species in Andalusia. First, samples were collected to estimate the moisture content of the plants; these data were collected from May 2007 to the present. Each species has its own range of moistures that depend on the time of year and the physiological state in which they are found. Secondly, an extensive database was obtained for each day of sample collection from the nearest weather station with free access. The statistics are performed at 12 solar hours on the day of sample collection and 24 h before collection, and then at 7 days, 14 days, 1 month, 3 months and 6 months before the day of collection. Finally, this database was statistically analyzed in two ways: Multiple linear regressions and random forest for each species. The predictive capacity of random forest is superior (R2 > 0.89) to that obtained in linear regression (R2 < 0.86). The highest root mean square error obtained in the case of the random forest is 0.74479 while in the linear regressions it was 1.29184. Consequently, uncertainty regarding fire behavior in the case of forest fires is reduced.

Wildfires impact on the economic susceptibility of recreation activities: Application in a Mediterranean protected area.

Development of many rural forestry areas depends strongly on tourism activities; therefore, it is critical to incorporate these activities in the decision-making process for the management and conservation efforts. Different from other market resources provided by forests, recreation activities provide benefits not only to forest owners but to all surrounding communities. Economic valuation of recreation activities requires using indirect valuation approaches like the travel cost method. Annual welfare estimates for the "Aracena y Picos de Aroche Natural Park" in southern Spain ranged from 25.30 € per recreationist for driving and travel time costs to 72.69 € per recreationist for these former costs plus associated incidental (food, lodging, etc.) costs. The annual value of this natural protected area was estimated at 3,656,609 € for the driving and travel time costs approach; and it was increased to 10,505,885.7 € for the total costs approach. Distributing the recreation welfare estimate proportionally is not reasonable as the visitation rate to different areas is different. Therefore, we use the individual recreational activities demand to distribute the estimated recreation value. Finally, we integrate the consumer surplus, the vegetation resilience and the potential fire behavior to estimate the fire recreation susceptibility. The fire susceptibility was increased by 58.25 million € from driving and travel time costs to total costs including incidental costs. Development of a socio-economic susceptibility framework using Geographic Information Systems provides an objective tool for budget allocation and prioritization of prevention activities and suppression actions during wildfires.

Modelling available crown fuel for Pinus pinaster Ait. stands in the "Cazorla, Segura and Las Villas Natural Park" (Spain).

One of the main limiting aspects in the application of crown fire models at landscape scale has been the uncertainty derived to describe canopy fuel stratum. Available crown fuel and canopy bulk density are essential in order to simulate crown fire behaviour and are of potential use in the evaluation of silvicultural treatments. Currently, the more accurate approach to estimate these parameters is to develop allometric models from common stand inventory data. In this sense, maritime pine (Pinus pinaster Aiton) trees were destructively sampled in the South of the Iberian Peninsula, covering natural and artificial stands. Crown fine fuel was separated into size classes and allometric equations that estimate crown fuel load by biomass fractions were developed. Available crown fuel was determined according to the fuel load differences between un-burned and burned trees with similar characteristics. Taking our destructive post-fire inventory into account, available crown fuel was estimated as the sum of needles biomass, 87.63% of the twigs biomass and 62.79% of the fine branches biomass. In spite of the differences between natural and artificial stands, generic models explained 82% (needles biomass), 89% (crown fuel), 92% (available crown fuel) and 94% (canopy bulk density) of the observed variation. Inclusion of the fitted models in fire management decision-making can provide a decision support system for assessing the potential crown fire of different silvicultural alternatives.

Spatio-temporal assessment of soil properties immediately and eight months after a high intensity-controlled burn in the south of Spain.

In recent years, the use of fire as a means by which to manage forest ecosystems has become more frequent in Europe. Fire has a significant impact on the soil, and it is therefore necessary to understand how controlled burns affect this invaluable resource. The purpose of this study was to evaluate the main alterations in the physical-chemical and biological properties of the soil because of a high intensity-controlled burn in "Los Boquerones" area (Villaviciosa de Córdoba, Spain). Additionally, we assessed the spatial heterogeneity of the alterations of different soil properties. A grid of 12 points was established on a hillside in Sierra Morena (Córdoba). Thermocouples were placed at each point, and soil samples were collected at two depths (0-2 cm and 2-5 cm) before burning, immediately after burning and eight months later. Soil pH, electrical conductivity, nutrient content and/or availability, among others, and their spatio-temporal variations were analysed. Soil pH, increased in the first centimetres of the soil (0-2 cm) immediately after burning up to >2 units, and the increase was maintained eight months following the burn. Additionally, the high-intensity burn had a positive short-term effect on some of the soil properties, such as nutrient availability for plants, which was considerably increased. The magnitude of the alterations in the soil indicators assessed was spatially explained by the behaviour of the fire during the controlled burning. The burn also had both direct and indirect effects on soil microorganisms. In conclusion, the possible immediate and short-term effects of burning on the soil resource should be considered for a more holistic management of fire in forest ecosystems, as its functionality and capacity to provide ecosystem services is largely altered by these events as a function of their intensity.

Economic susceptibility of fire-prone landscapes in natural protected areas of the southern Andean Range.

Large fires are the most important disturbances at landscape-level due to their ecological and socioeconomic impacts. This study aimed to develop an approach for the assessment of the socio-economic landscape susceptibility to fire. Our methodology focuses on the integration of economic components of landscape management based on contingent valuation method (CVM) and net-value change (NVC). This former component has been estimated using depreciation rates or changes on the number of arrivals to different natural protected areas after a large fire occurrence. Landscape susceptibility concept has been motivated by the need to assist fire prevention programs and environmental management. There was a remarkable variation in annual economic value attributed to each protected area based on the CVM scenario, ranging from 40,189-46,887$/year ("Tolhuaca National Park") to 241,000-341,953$/year ("Conguillio National Park"). We added landscape susceptibility using depreciation rates or tourist arrival decrease which varied from 2.04% (low fire intensity in "Tolhuaca National Park") to 76.67% (high fire intensity in "Conguillio National Park"). The integration of this approach and future studies about vegetation resilience should seek management strategies to increase economic efficiency in the fire prevention activities.

Prescribed fire experiences on crop residue removal for biomass exploitations. Application to the maritime pine forests in the Mediterranean Basin.

Socioeconomic changes, climate change, rural migration and fire exclusion have led to a high woody biomass accumulation increasing potential wildfire severity. Mechanical thinning and prescribed burning practices are commonly used to prevent large fires. The purpose of this study was to assess burning treatment effectiveness following mechanical thinning from biomass harvesting. Prescribed burning to reduce residue removal could help mitigate fire behavior, mainly in strategic management or critical focal points. Field samplings were conducted before and immediately after burnings on different environmental scenarios where fuel load was classified by categories. Prescribed fires reduced available fuel in all fuel categories, mainly in surface litter layer. Total fuel load reduction ranged from 59.07% to 86.18%. In this sense, fuel reduction effects were more pronounced when burns were conducted fewer than 10% on surface litter moisture. The difference in fuel consumption among scenarios was higher for most all woody fuel components and decomposition litter layer than for surface litter layer. Managers can use this information to design technical prescription to achieve the targets while decomposed litter retention maintaining the soil properties and biodiversity. Understanding the most effective "burn window" should help better plan prescribed burning, both in term of fire behavior and fuel consumption, without altering ecosystem properties.

A system to evaluate fire impacts from simulated fire behavior in Mediterranean areas of Central Chile.

Wildfires constitute the greatest economic disruption to Mediterranean ecosystems, from a socio-economic and ecological perspective (Molina et al., 2014). This study proposes to classify fire intensity levels based on potential fire behavior in different types of Mediterranean vegetation types, using two geographical scales. The study considered >4 thousand wildfires over a period of 25years, identifying fire behavior on each event, based on simulations using "KITRAL", a model developed in Chile in 1993 and currently used in the entire country. Fire intensity values allowed results to be classified into six fire effects categories (levels), each of them with field indicators linking energy values with damage related to burned vegetation and wildland urban interface zone. These indicators also facilitated a preliminary assessment of wildfire impact on different Mediterranean land uses and, are therefore, a useful tool to prioritize future interventions.