Fire Ecology最新文献

Background: Lightning-caused fires have a driving influence on Canadian forests, being responsible for approximately half of all wildfires and 90% of the area burned. We created a climatology (2000-2020) of daily lightning efficiency (i.e., the ratio of cloud-to-ground lightning flashes to lightning-caused wildfires that occurred) over the meteorological summer for four ecozones and a subset of British Columbia (BC) ecoprovinces. We estimated lightning efficiency using data from the Canadian Lightning Detection Network and the Canadian National Fire Database. We used the ERA5 reanalysis as inputs for fuel moisture variables (i.e., Fine Fuel Moisture Code (FFMC), Duff Moisture Code (DMC), and Drought Code (DC)) from the Canadian Forest Fire Weather Index (FWI) System, as well as variables relating to the amount of precipitation and lightning flashes. We examined relationships between lightning efficiency, day-of-year, and the above variables using a combination of linear models, Spearman's correlations, and Random Forest (RF) regression.

Results: Lightning efficiency increased non-linearly (i.e., quadratic) over the summer in the Montane Cordillera Ecozone, and decreased linearly in the Boreal Plains and Boreal Shield West. Lightning efficiency in the Boreal Shield East showed a slight decline over the summer; however, this model was not significant. DMC and DC were more strongly correlated with lightning efficiency than FFMC in most zones. We ran RF regression both with and without DC (because of multicollinearity with day-of-year), and day-of-year, DMC, and DC (when present) were the most important variables for all ecozones, while results were more variable for the ecoprovinces.

Conclusions: Lightning efficiency, and, thus, the probability of a lightning strike igniting a wildfire, changes over the summer and varies by region. Therefore, models predicting lightning-caused fire occurrence, or other similar applications involving lightning ignition, may benefit by accounting for seasonal lightning efficiency in addition to the traditional fuel moisture variables. Our work is generally consistent with findings from more localized studies relating to lightning-caused fires.

Supplementary information: The online version contains supplementary material available at 10.1186/s42408-025-00376-1.

Background: The increasing size, severity, and frequency of wildfires is one of the most rapid ways climate warming could alter the structure and function of high-latitude ecosystems. Historically, boreal forests in western North America had fire return intervals (FRI) of 70-130 years, but shortened FRIs are becoming increasingly common under extreme weather conditions. Here, we quantified pre-fire and post-fire C pools and C losses and assessed post-fire seedling regeneration in long (> 70 years), intermediate (30-70 years), and short (< 30 years) FRIs, and triple (three fires in < 70 years) burns. As boreal forests store a significant portion of the global terrestrial carbon (C) pool, understanding the impacts of shortened FRIs on these ecosystems is critical for predicting the global C balance and feedbacks to climate.

Results: Using a spatially extensive dataset of 555 plots from 31 separate fires in Interior Alaska, our study demonstrates that shortened FRIs decrease the C storage capacity of boreal forests through loss of legacy C and regeneration failure. Total wildfire C emissions were similar among FRI classes, ranging from 2.5 to 3.5 kg C m^-2. However, shortened FRIs lost proportionally more of their pre-fire C pools, resulting in substantially lower post-fire C pools than long FRIs. Shortened FRIs also resulted in the combustion of legacy C, defined as C that escaped combustion in one or more previous fires. We found that post-fire successional trajectories were impacted by FRI, with ~ 65% of short FRIs and triple burns experiencing regeneration failure.

Conclusions: Our study highlights the structural and functional vulnerability of boreal forests to increasing fire frequency. Shortened FRIs and the combustion of legacy C can shift boreal ecosystems from a net C sink or neutral to a net C source to the atmosphere and increase the risk of transitions to non-forested states. These changes could have profound implications for the boreal C-climate feedback and underscore the need for adaptive management strategies that prioritize the structural and functional resilience of boreal forest ecosystems to expected increases in fire frequency.

Supplementary information: The online version contains supplementary material available at 10.1186/s42408-025-00390-3.

Background: Increasing wildfire area burned has left millions of hectares in the western United States (US) in need of reforestation. Recent federal legislation allows for increased investments in tree planting to address the backlog of planting needs in previously burned areas. To support post-fire planning and assessment, we developed Regenmapper, a web-based decision support system (DSS) that provides spatial information on natural regeneration potential within post-fire environments. The program is freely available from a web browser (https://alpheus.dbs.umt.edu/regenmapper) and is designed to function across all land ownership categories for the 11 western States.

Results: Regenmapper allows users to select historical wildfires or upload their own burn severity maps for recent fires. Within the burned area, it then predicts the potential for natural regeneration based on distance to mature live trees (seed sources) and hydroclimatic conditions. To this end, we developed 30-m resolution soil water balance and surface temperature models with corresponding projections for the 2050 period based on scenarios from the 6th Coupled Model Intercomparison Project (CMIP6). These data are used to estimate the probability of natural seedling regeneration based on historical or future biophysical conditions, respectively, and species-specific climatic tolerances. We also implement a simple planting prioritization algorithm based on distance to roads and the relative effects of dispersal and climatic limitations to rapidly identify accessible sites that are unlikely to reforest naturally. For US Forest Service managers, we develop an additional prioritization matrix based on fire severity, the probability of natural regeneration, and where federal law mandates reforestation when fires burn through recently harvested areas. Finally, we demonstrate model outputs in a case study approach through the 2017 Lolo Peak fire in Montana, US.

Conclusions: Investments in tree planting will influence the extent and trajectory of future forests, but drought, climate change, and wildfires may challenge the ability of managers to re-establish forests over upcoming decades. DSS's like Regenmapper will benefit the planning and execution of tree planting efforts by reducing time required to conduct post-fire assessments and improving planting outcomes.

Supplementary information: The online version contains supplementary material available at 10.1186/s42408-025-00405-z.

Background: Prescribed fires play a critical role in reducing the intensity and severity of future wildfires by systematically and widely consuming accumulated vegetation fuel. While the current probability of prescribed fire escape in the United States stands very low, their consequential impact, particularly the large wildfires they cause, raises substantial concerns. The most direct way of understanding this trade-off between wildfire risk reduction and prescribed fire escapes is to explore patterns in the historical prescribed fire records. This study investigates the spatiotemporal patterns of escaped prescribed fires in California from 1991 to 2020, offering insights for resource managers in developing effective forest management and fuel treatment strategies.

Results: The results reveal that the months close to the beginning and end of the wildfire season, namely May, June, September, and November, have the highest frequency of escaped fires. Under similar environmental conditions, areas with more records of prescribed fire implementation tend to experience fewer escapes. The findings revealed the vegetation types most susceptible to escaped prescribed fires. Areas with tree cover ranging from 20 to 60% exhibited the highest incidence of escapes compared to shrubs and grasslands. Among all the environmental conditions analyzed, wind speed stands out as the predominant factor that affects the risk of prescribed fire escaping.

Conclusions: These findings mark an initial step in identifying high-risk areas and periods for prescribed fire escapes. Understanding these patterns and the challenges of quantifying escape rates can inform more effective landscape management practices.

Supplementary information: The online version contains supplementary material available at 10.1186/s42408-024-00342-3.

Background: Wildfire is a complex chemical, physical, and sociological phenomenon deeply rooted in the historical relationship between humans and fire. Today the wildfire risk is one of the human challenges. Effective management requires collaboration among multiple stakeholders across different levels. The risk perception and vulnerability at the local community level explain why and how individuals consider certain policies or mitigation behaviors. Thus, wildfire risk fits within the framework of socio-ecological systems.This study focused on four fire-prone areas in Tuscany, Italy, aiming to explore local wildfire risk perception. Risk perception is a social parameter, derived from media habits, memory, history, concerns, and beliefs. Two different surveys were used to consult two groups: experts (e.g., wildfire technicians, policymakers, business activities, and rural associations) and non-experts (e.g., random residents, students, and tourists), then compared to investigate possible gaps. Several questions were asked regarding demographics, relationship with the territory, current management system, relationship with fire and media, risk perception, and others.Results were compared according to the critical area or the type of respondents, and several analyses were conducted to identify weaknesses, strengths, and areas for improvement to raise awareness and lower the risk.

Results: Findings revealed differences in perception, more between the two groups than across locations, highlighting gaps that need to be addressed. A general underestimation of risk, with an overall optimism, was found in the non-expert group, indicating the need for further qualitative research to understand these aspects better. The interviews suggest public action as the main component to implement change.

Conclusions: The paradigm shift toward prevention represents a core change and challenge. An exchange between scientific and local knowledge is desirable to address many gaps. We propose awareness raising as a possible starting point and to encourage collective actions in line with suggestions from the interviewees. Continuous monitoring and evaluation of response patterns can inform policy adjustments and resource allocation to enhance resilience and response effectiveness in future emergencies. Further research could aim to develop tools to promote a culture of fire and risk and deepen the analysis of risk perception in the most critical areas.

Supplementary information: The online version contains supplementary material available at 10.1186/s42408-025-00380-5.