International Journal of Wildland Fire最新文献

Wildfires have caused significant damage in Chile, with critical infrastructure being vulnerable to extreme wildfires.

This work describes a methodology for estimating wildfire risk that was applied to an electrical substation in the wildland–urban interface (WUI) of Valparaíso, Chile.

Wildfire risk is defined as the product between the probability of a wildfire reaching infrastructure at the WUI and its consequences or impacts. The former is determined with event trees combined with modelled burn probability. Wildfire consequence is considered as the ignition probability of a proxy fuel within the substation, as a function of the incident heat flux using a probit expression derived from experimental data. The heat flux is estimated using modelled fire intensity and geometry and a corresponding view factor from an assumed solid flame.

The probability of normal and extreme fires reaching the WUI is of the order of 10⁻⁴ and 10⁻⁶ events/year, respectively. Total wildfire risk is of the order of 10⁻⁵ to 10⁻⁴ events/year

This methodology offers a comprehensive interpretation of wildfire risk that considers both wildfire likelihood and consequences.

The methodology is an interesting tool for quantitatively assessing wildfire risk of critical infrastructure and risk mitigation measures.

The post-fire recovery of soil microbes is critical for ecological conservation, yet the mechanisms behind it are not well understood.

In this study, we examined the recovery patterns of culturable soil microbes following a fire.

A field experiment was conducted in which a forest soil was subjected to surface fire, and the culturable microbial biomass and soil physicochemical characteristics were evaluated 1 day after the fire, and subsequently every 10 days for 90 days.

Microbial biomass significantly reduced post-fire, with varying effects across microbial taxa and soil layers. The recovery patterns of microbial biomass at topsoil (0–10 cm) and subsoil (10–20 cm), and among different microbial taxa were also different and were determined by the residual microbiomes. Heat released during a fire (the combination of heat duration and temperature reached during treatment) was significantly related to the decrease and recovery of microbial biomass, whereas there was no relationship between soil physicochemical properties and microbial biomass recovery.

Soil microbial biomass recovered quickly post-fire, which can be mainly due to the rapid attenuation of heat along the soil profile. Heat released during fire was the key factor determining the residual biomass, and the residual microbiomes determined the recovery patterns of the various taxa that comprise the culturable microbial biomass.

Due to the complexity of natural fire, simulated fire experiment and systematic sampling based on space (soil profile) and time are crucial to investigate the dynamics of soil microbes post-fire.

There is an ongoing need for improved understanding of wildfire plume dynamics.

To improve process-level understanding of wildfire plume dynamics including strong (>10 m s⁻¹) fire-generated winds and pyrocumulus (pyroCu) development.

Ka-band Doppler radar and two Doppler lidars were used to quantify plume dynamics during a high-intensity prescribed fire and airborne laser scanning (ALS) to quantify the fuel consumption.

We document the development of a strongly rotating (>10 m s⁻¹) pyroCu-topped plume reaching 10 km. Plume rotation develops during merging of discrete plume elements and is characterised by inflow and rotational winds an order of magnitude stronger than the ambient flow. Deep pyroCu is initiated after a sequence of plume-deepening events that push the plume top above its condensation level. The pyroCu exhibits a strong central updraft (~35 m s⁻¹) flanked by mechanically and evaporative forced downdrafts. The downdrafts do not reach the surface and have no impact on fire behaviour. ALS data show plume development is linked to large fuel consumption (~20 kg m⁻²).

Interactions between discrete plume elements contributed to plume rotation and large fuel consumption led to strong updrafts triggering deep pyroCu.

These results identify conditions conducive to strong plume rotation and deep pyroCu initiation.

Wildfires in Mediterranean-type climate regions have numerous impacts on the ecosystem services provided by native shrublands, however, quantifying these impacts is challenging.

We developed a reproducible method to quantify fire impacts on ecosystem services and created a tool for resource managers in southern California.

The SoCal EcoServe tool consists of two components: a desktop tool and an online mapping tool. We used the Alisal Fire of 2021 as a case study and quantified: aboveground live carbon storage using pre- and post-fire biomass data; water runoff, groundwater recharge and sediment erosion retention by integrating data on burn severity into hydrological and sediment erosion models; and estimated recreation services and biodiversity using pre-fire data.

We estimated the Alisal Fire resulted in an immediate post-fire reduction in carbon storage of 25%, of which 20% was estimated to be permanently lost. Water runoff increased by 21%, groundwater recharge 7-fold, and sediment erosion increased 24-fold.

The EcoServe tool provides an initial approximation of wildfire impacts that can support damage assessments post-fire, track carbon storage and help identify priorities for post-fire restoration.

We intend the tool to be used by USDA Forest Service resource managers of shurblands in southern California. However, it can provide the framework for future work in shrublands throughout the western USA.

The rising occurrence of simultaneous large wildfires has put strain on United States national fire management capacity leading to increasing reliance on assistance from partner nations abroad. However, limited analysis exists on international resource-sharing patterns and the factors influencing when resources are requested and deployed.

This study examines the drivers of international fire management ground and overhead personnel deployed to the United States.

Using descriptive statistics and case examples data from 2008 to 2020, this study investigates the conditions under which international personnel are deployed to the United States and their relationship to domestic resource strain. Factors such as fire weather, fire simultaneity, and the impact on people and structures are analysed as potential drivers of demand for international resources. Additionally, barriers to resource sharing, including overlapping fire seasons between countries are examined.

The findings indicate that international personnel sharing is more likely when the United States reaches higher preparedness levels, experiences larger area burned, and when fires pose a greater impact on people and structures. However, overlapping fire seasons can limit the ability to share resources with partner nations.

Understanding the factors influencing resource sharing can help improve collaboration efforts and enhance preparedness for future wildfire seasons.

When firefighters evacuate from wildfires, escape routes are crucial safety measures, providing pre-defined pathways to a safety zone. Their key evaluation criterion is the time it takes for firefighters to travel along the planned escape routes.

While shorter travel times can help firefighters reach safety zones faster, this may expose them to the threat of wildfires. Therefore, the safety of the routes must be considered.

We introduced a new evaluation indicator called the safety index by predicting the growth trend of wildfires. We then proposed a comprehensive evaluation cost function as an escape route planning model, which includes two factors: (1) travel time; and (2) safety of the escape route. The relationship between the two factors is dynamically adjusted through real time factor. The safety window within real time factor provides ideal safety margins between firefighters and wildfires, ensuring the overall safety of escape routes.

Compared with other models, the escape routes planned by the final improved model not only effectively avoid wildfires, but also provide relatively short travel time and reliable safety.

This study ensures sufficient safety margins for firefighters escaping in wildfire environments.

The escape route model described in this study offers a broader perspective on the study of escape route planning.

Fire regimes in many biomass-rich ecosystems worldwide are dominated by high-severity fires. Many of these systems lack fire-resistant traits or post-fire regeneration strategies. Understanding under which environmental and weather conditions they experience less severe fire is crucial for maintaining their persistence in the landscape.

Understand the spatial and temporal conditions that allow burn severity attenuation across Patagonia’s productivity gradient.

We modelled burn severity as a function of topography, weather, vegetation and productivity.

Low severity was a rare phenomenon, affecting only 8% of the areas burned. The probability of burning with high severity followed a hump-shaped relationship with productivity. Low severity occurred in fires that burned under cool and wet summer conditions in areas with sparser fuels or in wetter and more productive environments but with discontinuous and wet fuels.

Across the regional gradient, ecosystems of intermediate productivity generally lack conditions for low burn severity. Temporally, low burn severity occurs in smaller fires burning in productive ecosystems during cool and wet summers.

Future climate scenarios of increasing aridity and temperature in the region will disfavour conditions for low burn severity, thus promoting fire-mediated transitions from forests to alternative states dominated by more fire-adapted flammable species (e.g. shrublands).

Many species use hollows or cavities that form in trees. The effect of an increasing fire frequency on hollow-bearing trees is unclear.

To predict the effects of increasing fire frequency on the abundance of hollow-bearing trees and identify how to make forests more resilient to these changes.

We simulated how increasing fire frequency will affect the abundance of hollow-bearing trees in forests of south-eastern Australia and conducted a sensitivity analysis to identify which variables affect these predictions.

Other things being equal, we found a negative relationship between the number of hollow-bearing trees and increasing fire frequency. However, we identified scenarios where the number of hollow-bearing trees remained stable, or increased, with frequent fires.

Hollow-bearing trees will decline where frequent fires co-occur with high rates at which trees collapse (or are removed) and/or where there are not a sufficient number of suitable mature trees in which new hollows can be excavated by fire.

The impact of increasing fire frequency on hollow-dependent fauna is likely to be greatest in forests where regeneration is inhibited, a large number of trees are removed before they form hollows, and/or where rates of collapse among trees is elevated.

The record number of wildfires in the United States in recent years has led to an increased focus on developing tools to accurately forecast their impacts at high spatial and temporal resolutions.

The Warn-on-Forecast System for Smoke (WoFS-Smoke) was developed to improve these forecasts using wildfire properties retrieved from satellites to generate smoke plumes in the system.

The WoFS is a regional domain ensemble data assimilation and forecasting system built around the concept of creating short-term (0–6 h) forecasts of high impact weather. This work extends WoFS-Smoke by ingesting data from the GOES-16 satellite at 15-min intervals to sample the rapidly changing conditions associated with wildfires.

Comparison of experiments with and without GOES-16 data show that ingesting high temporal frequency data allows for wildfires to be initiated in the model earlier, leading to improved smoke forecasts during their early phases. Decreasing smoke plume intensity associated with weakening fires was also better forecast.

The results were consistent for a large fire near Boulder, Colorado and a multi-fire event in Texas, Oklahoma, and Arkansas, indicating a broad applicability of this system.

The development of WoFS-Smoke using geostationary satellite data allows for a significant advancement in smoke forecasting and its downstream impacts such as reductions in air quality, visibility, and potentially properties of severe convection.

Smouldering peatland wildfires can last for months and create a positive feedback for climate change. These flameless, slow-burning fires spread horizontally and vertically and are strongly influenced by peat moisture content. Most models neglect the non-uniform nature of peat moisture.

We conducted a computational study into the spread behaviour of smouldering peat with horizontally varying moisture contents.

We developed a discrete cellular automaton model called BARA, and calibrated it against laboratory experiments.

BARA demonstrated high accuracy in predicting fire spread under non-uniform moisture conditions, with >80% similarity between observed and predicted shapes, and captured complex phenomena. BARA simulated 1 h of peat smouldering in 3 min, showing its potential for field-scale modelling.

Our findings demonstrate: (i) the critical role of moisture distribution in determining smouldering behaviour; (ii) incorporating peat moisture distribution into BARA’s simple rules achieved reliable predictions of smouldering spread; (iii) given its high accuracy and low computational requirement, BARA can be upscaled to field applications.

BARA contributes to our understanding of peatland wildfires and their underlying drivers. BARA could form part of an early fire warning system for peatland.