Isolating the lightning ignition regime from a contemporary background fire regime in east-central Florida, USA

2010 ◽  
Vol 40 (2) ◽  
pp. 286-297 ◽  
Author(s):  
Brean W. Duncan ◽  
Frederic W. Adrian ◽  
Eric D. Stolen
Keyword(s):  
Fire Regime ◽  
Fire Regimes ◽  
Natural Fire ◽  
Central Florida ◽  
Pine Flatwoods ◽  
Ignition Regime ◽  
Equal Chance ◽  
Kennedy Space ◽  
Lightning Fire ◽  
In Fire

Anthropogenic influences have altered most fire regimes. Fire management programs often try to mimic natural fire regimes to maintain fuels and sustain native fire-dependent species. Lightning is the natural ignition source in Florida, substantiating the need for understanding lightning fire incidence. Sixteen years of lightning data (1986–2003, excluding 1987 and 2002 due to missing data) from the NASA Cloud to Ground Lightning Surveillance System and fire ignition records were used to quantify the relationship between lightning incidence and ignitions on Kennedy Space Center, Merritt Island National Wildlife Refuge, and Cape Canaveral Air Force Station. There were 230 lightning fires with an average of 14 ignitions per year, primarily in July, and only one winter ignition. Precipitation influenced the efficiency of lightning ignitions, particularly July precipitation. We found that negative polarity strikes caused the majority of ignitions. Pine flatwoods was ignited more frequently than expected given equal chance of ignition among landcover types. About half (51%) of detected fires were instantaneous ignitions and the other 49% were delayed an average of 2 days. This information is useful for paramaterizing fire regime models and for mimicking the natural fire regime through fire prescriptions on these properties and throughout the southeastern United States. These methods may be useful in fire-maintained systems globally.

Mixed-severity fire regimes: How well are they represented by existing fire-regime classification systems?

2013 ◽  
Vol 43 (7) ◽  
pp. 658-668 ◽  
Author(s):  
Hélène M. Marcoux ◽  
Sarah E. Gergel ◽  
Lori D. Daniels
Keyword(s):  
Field Data ◽  
Sustainable Forest Management ◽  
Fire Regime ◽  
Natural Disturbance ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Classification Systems ◽  
Fire Scars ◽  
Natural Fire ◽  
In Fire

Maps depicting historic fire regimes provide critical baselines for sustainable forest management and wildfire risk assessments. However, given our poor understanding of mixed-severity fire regimes, we asked if there may be considerable errors in fire-regime classification systems used to create landscape-level maps. We used dendrochronological field data (fire scars and tree establishment dates) from 20 randomly selected sites in southern British Columbia to evaluate two classification systems (Natural Disturbance Type (NDT) and Historical Natural Fire Regime (HNFR)) used by managers to map fire regimes. We found evidence of mixed-severity fires at 55% of sites. Each classification system made considerable and contrasting errors predicting mixed-severity regimes (relative to field data), and the discrepancies varied with elevation. The NDT system underrepresented low-to-moderate-severity fires at lower elevations, whereas the HNFR system overpredicted their occurrence at higher elevations. Errors are attributed to underlying assumptions about disturbances in the two classification systems, as well as limitations of the research methods used to estimate fire frequency in mixed-severity regimes (i.e., methods more relevant to high- versus low-severity regimes). Ecological heterogeneity created by mixed-severity regimes potentially influences decisions related to conservation, silviculture, wildfire, and fuel mitigation. Thus, understanding underlying assumptions and errors in mapping fire regimes is critical.

scholarly journals Modelling the drivers of natural fire activity: the bias created by cropland fires

2017 ◽  
Vol 26 (10) ◽  
pp. 845 ◽  
Author(s):  
İsmail Bekar ◽  
Çağatay Tavşanoğlu
Keyword(s):  
Linear Models ◽  
Fire Regime ◽  
Fire Regimes ◽  
Activity Data ◽  
Generalised Linear Models ◽  
Natural Fire ◽  
Geographic Factors ◽  
Fire Activity ◽  
Climatic Anthropogenic ◽  
In Fire

Wildland and cropland fires, which differ considerably in fire regime characteristics, have often been evaluated jointly to estimate regional or global fire regimes using satellite-based fire activity data. We hypothesised that excluding cropland fires will change the output of the models regarding the drivers of natural fire activity. We modelled MODIS fire activity data of western and southern Turkey for the years 2000–2015 using binomial generalised linear models in which many climatic, anthropogenic and geographic factors were included as predictor variables. For modelling, we used different datasets created by the exclusion of various cropland and vegetation land cover classes. More fire activity was observed as the number of cropland-dominated cells increased in a dataset. The explained deviance (%) of the binomial GLM differed substantially in the separate datasets for most of the variables. Moreover, excluding croplands gradually from the overall dataset resulted in a substantial decrease in the explained deviance (%) in the models for all variables. The results suggest that cropland fires have a significant effect on the output of fire regime models. Therefore, a clear distinction should be drawn between wildland and cropland fires in such models for a better understanding of natural fire activity.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

scholarly journals Historical fire records at the two ends of Iberian Central Mountain System: Estrela massif and Ayllón massif

2019 ◽  
pp. 31
Author(s):  
Catarina Romão Sequeira ◽  
Cristina Montiel-Molina ◽  
Francisco Castro Rego
Keyword(s):  
Fire Regime ◽  
Fire Regimes ◽  
Historical Record ◽  
Multiscale Approach ◽  
Natural Region ◽  
Fire Use ◽  
Prone Area ◽  
Mountain System ◽  
History Of ◽  
In Fire

The Iberian Peninsula has a long history of fire, as the Central Mountain System, from the Estrela massif in Portugal to the Ayllón massif in Spain, is a major fire-prone area. Despite being part of the same natural region, there are different environmental, political and socio-economic contexts at either end, which might have led to distinct human causes of wildfires and associated fire regimes. The hypothesis for this research lies in the historical long-term relationship between wildfire risks and fire use practices within a context of landscape dynamics. In addition to conducting an analysis of the statistical period, a spatial and temporal multiscale approach was taken by reconstructing the historical record of prestatistical fires and land management history at both ends of the Central Mountain System. The main result is the different structural causes of wildland fires at either end of the Central Mountain System, with human factors being more important than environmental factors in determining the fire regimes in both contexts. The study shows that the development of the fire regime was non-linear in the nineteenth and twentieth centuries, due to broader local human context factors which led to a shift in fire-use practices.

Differences in germination response to smoke and temperature cues in ‘pyrophyte’ and ‘pyrofuge’ forms of Erica coccinea (Ericaceae)

2018 ◽  
Vol 27 (8) ◽  
pp. 562 ◽  
Author(s):  
Jenny Leonard ◽  
Adam G. West ◽  
Fernando Ojeda
Keyword(s):  
South African ◽  
Incubation Temperature ◽  
Fire Regimes ◽  
Smoke Exposure ◽  
The South ◽  
Natural Fire ◽  
Germination Response ◽  
High Germination ◽  
Germination Success ◽  
In Fire

Many plants in fire-prone ecosystems produce seeds that are cued to germinate after fire. However, fire is not uniform in the landscape, and there are often refugia where fire does not reach, like rocky outcrops or moist valleys. Erica coccinea, a heath shrub from the South African fynbos, has two distinct pyrophyte forms (a resprouter and a seeder) as well as a ‘pyrofuge’ form that only occurs in fire refugia. We measured germination response to smoke and incubation temperature in seeds from pyrophyte (resprouter and seeder) and pyrofuge populations to determine whether these forms responded differently to a fire-cue (smoke) and a general germination cue (temperature). We found that seeds from pyrofuge plants had high germination success (80.9–92.0%) at the lowest incubation temperature (15/8°C 12h day/night cycle) regardless of smoke exposure. In contrast, seeds from pyrophytes (resprouters and seeders) responded strongly to the smoke cue (71.2–95.0%) and were not as limited by temperature. These results show that fire presence and absence is driving divergence of the primary germination cue in Erica coccinea. Given the patchiness of many natural fire regimes worldwide, we expect there may be pyrofuge populations exhibiting a similar divergence of traits in other species and other fire-prone ecosystems.

Mapping fire regime ecoregions in California

2020 ◽  
Vol 29 (7) ◽  
pp. 595 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
Fire Regime ◽  
Fire Severity ◽  
Fire Regimes ◽  
Unsupervised Classification ◽  
Fire Frequency ◽  
The State ◽  
Reduction Strategies ◽  
Lower Variability ◽  
Fire Characteristics ◽  
In Fire

The fire regime is a central framing concept in wildfire science and ecology and describes how a range of wildfire characteristics vary geographically over time. Understanding and mapping fire regimes is important for guiding appropriate management and risk reduction strategies and for informing research on drivers of global change and altered fire patterns. Most efforts to spatially delineate fire regimes have been conducted by identifying natural groupings of fire parameters based on available historical fire data. This can result in classes with similar fire characteristics but wide differences in ecosystem types. We took a different approach and defined fire regime ecoregions for California to better align with ecosystem types, without using fire as part of the definition. We used an unsupervised classification algorithm to segregate the state into spatial clusters based on distinctive biophysical and anthropogenic attributes that drive fire regimes – and then used historical fire data to evaluate the ecoregions. The fire regime ecoregion map corresponded well with the major land cover types of the state and provided clear separation of historical patterns in fire frequency and size, with lower variability in fire severity. This methodology could be used for mapping fire regimes in other regions with limited historical fire data or forecasting future fire regimes based on expected changes in biophysical characteristics.

scholarly journals The status and challenge of global fire modelling

2016 ◽  
Author(s):  
S. Hantson ◽  
A. Arneth ◽  
S. P. Harrison ◽  
D. I. Kelley ◽  
I. C. Prentice ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Fire Regime ◽  
Fire Regimes ◽  
Climate Projections ◽  
Data Sets ◽  
Predictive Skill ◽  
Current State ◽  
Fire Modelling ◽  
The Status ◽  
In Fire

Abstract. Biomass burning impacts vegetation dynamics, biogeochemical cycling, atmospheric chemistry, and climate, with sometimes deleterious socio-economic impacts. Under future climate projections it is often expected that the risk of wildfires will increase. Our ability to predict the magnitude and geographic pattern of future fire impacts rests on our ability to model fire regimes, either using well-founded empirical relationships or process-based models with good predictive skill. A large variety of models exist today and it is still unclear which type of model or degree of complexity is required to model fire adequately at regional to global scales. This is the central question underpinning the creation of the Fire Model Intercomparison Project – FireMIP, an international project to compare and evaluate existing global fire models against benchmark data sets for present-day and historical conditions. In this paper we summarise the current state-of-the-art in fire regime modelling and model evaluation, and outline what lessons may be learned from FireMIP.

Inter- and intra-annual profiles of fire regimes in the managed forests of Canada and implications for resource sharing

2012 ◽  
Vol 21 (4) ◽  
pp. 328 ◽  
Author(s):  
Steen Magnussen ◽  
Stephen W. Taylor
Keyword(s):  
Resource Sharing ◽  
Joint Distribution ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Season ◽  
Burned Area ◽  
Fire Activity ◽  
In Fire ◽  
Regional Synchrony

Year-to-year variation in fire activity in Canada constitutes a key challenge for fire management agencies. Interagency sharing of fire management resources has been ongoing on regional, national and international scales in Canada for several decades to better cope with peaks in resource demand. Inherent stressors on these schemes determined by the fire regimes in constituent jurisdictions are not well known, nor described by averages. We developed a statistical framework to examine the likelihood of regional synchrony of peaks in fire activity at a timescale of 1 week. Year-to-year variations in important fire regime variables and 48 regions in Canada are quantified by a joint distribution and profiled at the Provincial or Territorial level. The fire regime variables capture the timing of the fire season, the average number of fires, area burned, and the timing and extent of annual maxima. The onset of the fire season was strongly correlated with latitude and longitude. Regional synchrony in the timing of the maximum burned area within fire seasons delineates opportunities for and limitations to sharing of fire suppression resources during periods of stress that were quantified in Monte Carlo simulations from the joint distribution.

Assessing accuracy of point fire intervals across landscapes with simulation modelling

2007 ◽  
Vol 37 (9) ◽  
pp. 1605-1614 ◽  
Author(s):  
Russell A. Parsons ◽  
Emily K. Heyerdahl ◽  
Robert E. Keane ◽  
Brigitte Dorner ◽  
Joseph Fall
Keyword(s):  
Fire Regime ◽  
Fire Regimes ◽  
Maximum Error ◽  
Simulation Modelling ◽  
Fire Frequency ◽  
Spatially Explicit ◽  
Forest Types ◽  
Fire Scar ◽  
Fire Intervals ◽  
In Fire

We assessed accuracy in point fire intervals using a simulation model that sampled four spatially explicit simulated fire histories. These histories varied in fire frequency and size and were simulated on a flat landscape with two forest types (dry versus mesic). We used three sampling designs (random, systematic grids, and stratified). We assessed the sensitivity of estimates of Weibull median probability fire intervals (WMPI) to sampling design and to factors that degrade the fire scar record: failure of a tree to record a fire and loss of fire-scarred trees. Accuracy was affected by all of the factors investigated and generally varied with fire regime type. The maximum error was from degradation of the record, primarily because degradation reduced the number of intervals from which WMPI was estimated. The sampling designs were roughly equal in their ability to capture overall WMPI, regardless of fire regime, but the gridded design yielded more accurate estimates of spatial variation in WMPI. Accuracy in WMPI increased with increasing number of points sampled for all fire regimes and sampling designs, but the number of points needed to obtain accurate estimates was greater for fire regimes with complex spatial patterns of fire intervals than for those with relatively homogeneous patterns.

A refinement of models projecting future Canadian fire regimes using homogeneous fire regime zones

2014 ◽  
Vol 44 (4) ◽  
pp. 365-376 ◽  
Author(s):  
Yan Boulanger ◽  
Sylvie Gauthier ◽  
Philip J. Burton
Keyword(s):  
Large Scale ◽  
Fire Regime ◽  
Fold Increase ◽  
Fire Regimes ◽  
Multivariate Adaptive Regression Splines ◽  
Energy Flows ◽  
Fire Activity ◽  
Ecological Patterns ◽  
Administrative Units ◽  
In Fire

Broad-scale fire regime modelling is frequently based on large ecological and (or) administrative units. However, these units may not capture spatial heterogeneity in fire regimes and may thus lead to spatially inaccurate estimates of future fire activity. In this study, we defined homogeneous fire regime (HFR) zones for Canada based on annual area burned (AAB) and fire occurrence (FireOcc), and we used them to model future (2011–2040, 2041–2070, and 2071–2100) fire activity using multivariate adaptive regression splines (MARS). We identified a total of 16 HFR zones explaining 47.7% of the heterogeneity in AAB and FireOcc for the 1959–1999 period. MARS models based on HFR zones projected a 3.7-fold increase in AAB and a 3.0-fold increase in FireOcc by 2100 when compared with 1961–1990, with great interzone heterogeneity. The greatest increases would occur in zones located in central and northwestern Canada. Much of the increase in AAB would result from a sharp increase in fire activity during July and August. Ecozone- and HFR-based models projected relatively similar nationwide FireOcc and AAB. However, very high spatial discrepancies were noted between zonations over extensive areas. The proposed HFR zonation should help providing more spatially accurate estimates of future ecological patterns largely driven by fire in the boreal forest such as biodiversity patterns, energy flows, and carbon storage than those obtained from large-scale multipurpose classification units.

Sign in / Sign up

Export Citation Format

Share Document