International Journal of Wildland Fire最新文献

Background: Daily fire progression information is crucial for public health studies that examine the relationship between population-level smoke exposures and subsequent health events. Issues with remote sensing used in fire emissions inventories (FEI) lead to the possibility of missed exposures that impact the results of acute health effects studies.

Aims: This paper provides a method for improving an FEI dataset with readily available information to create a more robust dataset with daily fire progression.

Methods: High temporal and spatial resolution burned area information from two FEI products are combined into a single dataset, and a linear regression model fills gaps in daily fire progression.

Key results: The combined dataset provides up to 71% more PM_2.5 emissions, 69% more burned area, and 367% more fire days per year than using a single source of burned area information.

Conclusions: The FEI combination method results in improved FEI information with no gaps in daily fire emissions estimates.

Implications: The combined dataset provides a functional improvement to FEI data that can be achieved with currently available data.

Background: Rural communities are increasingly impacted by smoke produced by wildfires and forest management activties. Understanding local influences on smoke adaptation and mitigation is critical to social adaptation as fire risk continues to rise.

Aims: We sought to determine the role of local social context in smoke adaptation and gauge interest in adaptation strategies that might reduce exposure.

Methods: We conducted 46 semi-structured interviews with 56 residents and professionals in Parks, Arizona, USA, a rural community adjacent to public lands regularly affected by smoke.

Key results: Rural residents think of smoke as an acceptable risk. Efforts to adapt to potential health impacts are minimal, though inaction is driven by diverse reasoning and tradeoffs. Local social context - particularly elements related to government distrust, forest management, and independence - heavily influences interest in uptake of different adaptation strategies as well as affecting access to, and interpretation of, information about smoke risks.

Conclusions: Rural approaches to, and understandings of, smoke adaptation vary spatially and temporally. Public interest in broader forest management efforts can be leveraged to engage residents in conversations about proactive smoke adaptation.

Implications: Smoke adaptation strategies in rural communities must meld evidence of their effectiveness with community preferences grounded in local context to overcome inaction.

Predicting fire behaviour is an ongoing challenge in temperate peatlands and heathlands, where live fuels can form the dominant fuel load for wildfire spread, and where spatial heterogeneity in fuel moisture is important but not typically represented in fuel models.

We examine the impact of fuel moisture variation on simulated fire behaviour across a temperate peatland/heathland landscape.

We collected field measurements of fuel moisture content in Calluna vulgaris shrub from 36 sites across the North Yorkshire Moors, United Kingdom. We used these to define fuel moisture inputs within existing shrubland fuel models to simulate fire behaviour in BehavePlus.

Simulated rates of spread varied with fuel moisture content; average mean variance of 23–80% from the landscape average rate of spread. The driest sites had simulated rates of spread up to 135% above the landscape average and the wettest sites up to 86% below average. Fuel model selection dramatically impacted simulated rates of spread by a factor of five.

We need to constrain the role of live fuel moisture within temperate fuel models to develop accurate fire behaviour predictions.

Capturing cross-landscape heterogeneity in fire behaviour is important for safe and effective land and wildfire management decision-making.

We use case studies to explore the impact of changed fire regimes on vegetation structure and fuel risk in Southeast Queensland, Australia. Multiple studies report high intensity wildfires promote excessive shrub and sapling densities, which increase elevated fuel hazard. We argue asset protection burns in dry conditions can cause similar vegetation thickening to an intense wildfire, which increases fire severity risk due to increased elevated fuel loads. We demonstrate regular low intensity burning with adequate soil moisture can achieve fuel reduction objectives. This provides a longer-term solution that promotes risk reduction to communities, whilst leading to better ecological outcomes and reduced cost of implementation over the long-term.

As fire regimes continue to evolve in response to climate change, understanding how fire characteristics have responded to changes in the recent past is vital to inform predictions of future fire events.

Using Fourier Transform Infrared (FTIR) spectroscopy, we assessed how fire intensity has changed in two fire-prone landscapes in south-eastern Australia: (1) the Blue Mountains; and (2) Namadgi National Park during the past 3000 years.

Higher aromatic/aliphatic ratios suggest increased high-intensity fire frequency in sediments at the surface of both cores. Increases in the frequency of extreme drought periods, coupled with the change in vegetation and anthropogenic ignitions following colonisation, could have increased the frequency of high-intensity fires in the past ~200 years.

FTIR spectroscopy can be used in sediment deposits to infer that the frequency of high-intensity fire events has increased in the past 200 years compared to the previous ~3000 years.

These results are important for understanding how past fire regimes have responded to climate, people and vegetation shifts in the past ~3000 years and can be used to inform models for future predictions and management strategies.

Fires release large pulses of nitrogen (N), which can be taken up by recovering plants and microbes or exported to streams where it can threaten water quality.

The amount of N exported depends on the balance between N mineralisation and rates of N uptake after fire. Burn severity and soil moisture interact to drive these rates, but their effects can be difficult to predict.

To understand how soil moisture and burn severity influence post-fire N cycling and retention in a dryland watershed, we quantified changes in plant biomass, plant N content, soil microbial biomass, inorganic N pools, and net N mineralisation for 2 years after fire. We compared sites that were unburned with those that burned at moderate or high severity, capturing variation in soil moisture within each severity category.

Severe fire limited N uptake by plants. Dry conditions after fire limited both plant and microbial N uptake.

When fire is severe or when soils are relatively dry after fire, recovering plants and microbes are less likely to take up post-fire N and therefore, N in these sites is more susceptible to export.

Wildfire propagation is inherently non-steady, although forecasts of their spread focus on a pseudo-steady state assumption.

To investigate the variability in rate of fire spread of wildfires in southern Australian grassland landscapes, and the effect of landscape features in inhibiting fire propagation. To evaluate the adequacy of grassfire rate of spread models currently used in Australia.

We reconstructed the propagation of six wildfires in grassland fuels and characterised the unsteady nature of rate of spread. We also analysed the effect of barriers to fire spread in slowing or halting wildfire propagation.

Headfire rate of spread in wildfires was observed to be non-steady, with peaks in forward rate of spread being on average 2.6-times higher than mean values. The rate of spread had an average coefficient of variation of 88%. Areas of fuel discontinuity, such as roads, did not stop fires under moderate burning conditions, but resulted in slowing the average rate of fire spread.

Analysis of wildfire observations is key to understand fire behaviour features that are not replicable in experimental or modelling environments. Findings from the analysis can support fire-fighting safety awareness and inform landscape fire propagation modelling.

Balanggarra, Dambimangari, Wilinggin and Wunambal Gaambera Traditional Owners in Western Australia operate Savanna Fire Management projects under the collective North Kimberley Fire Abatement Project.

We examine changes to the fire regime before and after the initiation of these projects and discuss implications for incentivising savanna fire management.

Using established methods and high-resolution imagery, we compared fire metrics between baseline (2001–2011) and project years (2012–2022).

Fire seasonality notably shifted from late to early dry season dominance with fewer late season fires across, resulting in carbon abatement. While total area burnt remained similar, annual fire pattern transitioned from a cyclical to less variable regime. Fire patchiness, fire age diversity, and area of long unburnt vegetation increased while fire frequency decreased. A minimum of 4 years of fire management was required before significant changes in fire metrics were observed.

The fire regime on Traditional Owner lands has improved significantly, enabled by the emergence of land and sea management, carbon markets, support of partner agencies, and the securing of land rights.

Beyond carbon credits, access to technology holds promise for sustained improvements to adaptive fire management built on strong foundations of traditional burning practices.

Situational awareness is an essential component of wildland firefighter safety. In the US, crew lookouts provide situational awareness by proxy from ground-level locations with visibility of both fire and crew members.

To use machine learning to predict potential lookout locations based on incident data, mapped visibility, topography, vegetation, and roads.

Lidar-derived topographic and fuel structural variables were used to generate maps of visibility across 30 study areas that possessed lookout location data. Visibility at multiple viewing distances, distance to roads, topographic position index, canopy height, and canopy cover served as predictors in presence-only maximum entropy modelling to predict lookout suitability based on 66 known lookout locations from recent fires.

The model yielded a receiver-operating characteristic area under the curve of 0.929 with 67% of lookouts correctly identified by the model using a 0.5 probability threshold. Spatially explicit model prediction resulted in a map of the probability a location would be suitable for a lookout; when combined with a map of dominant view direction these tools could provide meaningful support to fire crews.

This approach could be applied to produce maps summarising potential lookout suitability and dominant view direction across wildland environments for use in pre-fire planning.

Knowledge of how fire regimes influence flammability, and its role in shaping future fire regimes, exists mostly at species composition and ecosystem levels. The effect of fire regimes on fuel at the chemical level is poorly known.

We aimed to empirically investigate the association between recent fire history and forest foliage chemistry; and to explore potential implications for forest fuel flammability.

Using an orthogonal study design, we investigated the effects of fire frequency and time since fire on the chemical composition of Eucalyptus pilularis leaves from forest canopies and surface litter in south-eastern Australia.

We found high fire frequency (fire-return interval 10–13 years) was associated with higher C:N, C:P, and C:K ratios in E. pilularis surface litter, and higher C:P in canopy leaves.

Nutrients including nitrogen and phosphorous reduce flammability of plant tissues, and hence, the observed differences in leaf nutrients between high and low fire frequency sites could have important implications for future flammability of these forests.

Our study has demonstrated a relationship between fire frequency and leaf nutrient stoichiometry, which may act as a mechanism through which repeated fires could increase fuel flammability. This warrants further investigation in other environments.