scholarly journals Fuel age, weather and burn probability in Portugal

2012 ◽  
Vol 21 (4) ◽  
pp. 380 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Carlos Loureiro ◽  
Marco Magalhães ◽  
Pedro Ferreira ◽  
Manuel Fernandes
Keyword(s):  
Fire Suppression ◽  
Weather Conditions ◽  
Age Dependency ◽  
Fire Return Interval ◽  
Return Interval ◽  
Free Interval ◽  
Burn Probability ◽  
Fire Atlas ◽  
Censored Observations ◽  
Fire Intervals

The relative influence of the factors acting on burn probability, namely fuel and weather, is not well understood, especially in Europe. We use a digital fire atlas (1975–2008) and apply survival analysis to individual fires (1998–2008) to describe how burn probability changes with fuel age in Portugal. The typical fire return interval and median fire-free interval vary regionally from 23 to 52 and 18 to 47 years. Increase of the hazard of burning with time is generally near-linear, denoting moderate fuel-age dependency, as in some other shrub-dominated Mediterranean environments. Analysis of complete fire intervals resulted in shorter fire return interval and higher fuel-age dependency of burn probability than findings that included censored observations. Increasingly severe weather conditions either expressed through fire size or by extreme fire danger concurrently decreased fuel-age dependency and selected older fuels. The results are discussed from the viewpoints of fire suppression and fuel treatments.

A 400-year history of fires on lake islands in south-east Sweden

2010 ◽  
Vol 19 (8) ◽  
pp. 1050 ◽  
Author(s):  
Mats Niklasson ◽  
Igor Drobyshev ◽  
Tomasz Zielonka
Keyword(s):  
18Th Century ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Spread ◽  
Small Islands ◽  
Fire Return Interval ◽  
Lake Ecosystems ◽  
Return Interval ◽  
Fire Disturbances ◽  
Fire Intervals

Island-lake ecosystems are suitable for testing scale dependence in forests disturbance theories thanks to differences in the potential for fire spread on islands and the mainland. We investigated past fire regime on the mainland and on islands in a large lake in south-east Sweden. We used dendrochronological methods to reconstruct fire disturbances on 18 small islands (0.04–24.1 ha) and in 43 sites in the surrounding 75-km2 landscape over the last 400 years. In the past, fires were frequent on both islands and mainland but not synchronised on an annual scale. Significant temporal changes occurred around the middle of the 18th century. Before 1750, fires were less frequent on islands than on the mainland (median fire return interval 58 v. 25 years respectively). However, an inversion of this pattern was observed during 1750–1860: islands showed even shorter fire intervals than mainland locations, suggesting additional and likely human-related source of ignitions (median fire return interval 15 v. 29 years respectively). A substantial decrease in fire activity in both islands and mainland was apparent in 1860–1890. We suggest that the present fire regime (the last 100 years) on the small islands is largely natural as fire suppression is not present there. The dynamic nature of the fire regime on islands still requires further studies: islands may, at times, attract lightning, humans with fire, or both.

Relationship between fire-return interval and mulga (Acacia aneura) regeneration in the Gibson Desert and Gascoyne–Murchison regions of Western Australia

2014 ◽  
Vol 23 (3) ◽  
pp. 394 ◽  
Author(s):  
Bruce G. Ward ◽  
Thomas B. Bragg ◽  
Barbara A. Hayes
Keyword(s):  
Western Australia ◽  
Fire Size ◽  
Seedling Regeneration ◽  
Fire Return Interval ◽  
Return Interval ◽  
Population Average ◽  
Ring Analysis ◽  
Acacia Aneura ◽  
Fire Intervals ◽  
Landsat Satellite

A study of 26 burnt mulga (Acacia aneura) stands was conducted from 2003 to 2012 in the Gibson Desert and eastern Gascoyne–Murchison region of Western Australia to assess the effect of fire interval on seedling regeneration. Tree-ring analysis and Landsat satellite imagery identified mulga stands with fire intervals ranging from 3 to 52 years. Results show fire-return intervals less than 20 years produce 2–3-year-old seedling regeneration lower than 50% of the original adult stand population (average juvenile-to-adult ratio=0.49). In total, 6 of the 26 stands sampled had reburnt within 3 to 10 years of the previous burn, a consequence of increased plant growth associated with higher rainfall. For all fires, summer fires were larger and more frequent (24 of 35 fires recorded, median fire size=150km2) than spring fires (median fire size=91km2). This study emphasises the important role of fire in maintaining the diversity and vigour of the mulga–Triodia ecosystem but indicates a minimum fire-return interval of 26 years to maintain mulga populations.

Climate - fire interactions during the Holocene: a test of the utility of charcoal morphotypes in a sediment core from the boreal region of north-western Ontario (Canada)

2012 ◽  
Vol 21 (6) ◽  
pp. 640 ◽  
Author(s):  
Melissa T. Moos ◽  
Brian F. Cumming
Keyword(s):  
Sediment Core ◽  
Late Holocene ◽  
Fold Increase ◽  
Fire Frequency ◽  
Accumulation Rates ◽  
Fire Return Interval ◽  
The Holocene ◽  
Return Interval ◽  
In Fire ◽  
North Western

Charcoal accumulation rates and fire-return intervals were calculated from total charcoal and charcoal morphotypes over the Holocene, from a well-dated sediment core from Lake 239 located in north-western Ontario, and compared with previously published independent climate reconstructions. Both total and morphotype analysis show a two-to-three fold increase in accumulation rates in the early-to-mid Holocene (range: 1 to 6 pieces cm–2 year–1) compared with the early and late Holocene (range: 0 to 2 pieces cm–2 year–1). Fire-return intervals and fire frequencies calculated during these periods, based on peak analysis, showed very different trends. The fire-return interval based on Type M charcoal, a morphotype associated with primary charcoal deposition, was high during the early and late Holocene, and low from ~7500 to 4000 cal year BP, with high inferred fire frequency during the warm mid-Holocene (~12.5 fires per 1000 years), compared with <5 fires per 1000 years over the rest of the Holocene, whereas fire-return interval and fire frequency based on total charcoal did not show patterns consistent with climate. These results suggest that a two- to three-fold increase in fire frequency would not be unexpected in the future under a predicted warmer climate.

scholarly journals The Role of Fire-Return Interval and Season of Burn in Snag Dynamics in a South Florida Slash Pine Forest

Fire Ecology ◽  
2012 ◽  
Vol 8 (3) ◽  
pp. 18-31 ◽  
Author(s):  
John D. Lloyd ◽  
Gary L. Slater ◽  
James R. Snyder
Keyword(s):  
Pine Forest ◽  
Slash Pine ◽  
South Florida ◽  
Fire Return Interval ◽  
Return Interval ◽  
Season Of Burn ◽  
Snag Dynamics

scholarly journals Event-Based Integrated Assessment of Environmental Variables and Wildfire Severity through Sentinel-2 Data

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1021 ◽  
Author(s):  
Juan Picos ◽  
Laura Alonso ◽  
Guillermo Bastos ◽  
Julia Armesto
Keyword(s):  
Land Cover ◽  
Forest Fires ◽  
Fire Suppression ◽  
Fire Severity ◽  
Environmental Parameters ◽  
Weather Conditions ◽  
Integrated Approach ◽  
Policy Makers ◽  
Event Based ◽  
Sentinel 2

To optimize suppression, restoration, and prevention plans against wildfire, postfire assessment is a key input. Since little research has been carried out on applying Sentinel-2 imagery through an integrated approach to evaluate how environmental parameters affect fire severity, this work aims to fill this gap. A set of large forest fires that occurred in northwest Spain during extreme weather conditions were adopted as a case study. Sentinel-2 information was used to build the fire severity map and to evaluate the relation between it and a set of its driving factors: land cover, aspect, slope, proximity to the nearest stream, and fire recurrence. The cover types most affected by fire were scrubland, rocky areas, and Eucalyptus. The presence of streams was identified as a major cause of the reduced severity of fires in broadleaves. The occurrence of fires in the past is linked to the severity of fires, depending on the land cover. This research aims to help fire researchers, authority managers, and policy makers distinguish the conditions under which the damage by fire is minimized and optimize the resources allocated to restoration and future fire suppression.

Estimating natural forest fire return interval in northeastern Ontario, Canada

2009 ◽  
Vol 258 (9) ◽  
pp. 2037-2045 ◽  
Author(s):  
Michael T. Ter-Mikaelian ◽  
Stephen J. Colombo ◽  
Jiaxin Chen
Keyword(s):  
Forest Fire ◽  
Natural Forest ◽  
Fire Return Interval ◽  
Return Interval

How does increased fire frequency affect carbon loss from fire? A case study in the northern boreal forest

2011 ◽  
Vol 20 (7) ◽  
pp. 829 ◽  
Author(s):  
C. D. Brown ◽  
J. F. Johnstone
Keyword(s):  
Boreal Forests ◽  
Forest Canopy ◽  
Short Interval ◽  
Fire Frequency ◽  
Fire Return Interval ◽  
Fire Cycle ◽  
Return Interval ◽  
Canopy Soil ◽  
Carbon Stores ◽  
Stand Conditions

Fire frequency is expected to increase due to climate warming in many areas, particularly the boreal forests. An increase in fire frequency may have important effects on the global carbon cycle by decreasing the size of boreal carbon stores. Our objective was to quantify and compare the amount of carbon consumed during and the amount of carbon remaining following fire in black spruce (Picea mariana (Mill.) BSP) forests burned after long v. short intervals. We hypothesised that stands with a shortened fire return interval would have a higher carbon consumption than those experiencing a historically typical fire return interval. Using field measurements of forest canopy, soil organic horizons and adventitious roots, we reconstructed pre-fire stand conditions to estimate the biomass lost in each fire and the effects on post-fire residual carbon stores. We found evidence of a higher loss of carbon following two fire events that recurred after a short interval, resulting in a much greater total reduction in carbon relative to pre-fire or mature stand conditions. Consequently, carbon storage across disturbance intervals was dramatically reduced following short-interval burns. Recovery of these stores would require a subsequent lengthening of the fire cycle, which appears unlikely under future climate scenarios.

Reproductive biology, post-fire succession dynamics and population viability analysis of the critically endangered Western Australian shrub Calytrix breviseta subsp. breviseta (Myrtaceae)

2009 ◽  
Vol 57 (6) ◽  
pp. 451 ◽  
Author(s):  
Andrew P. Nield ◽  
Philip G. Ladd ◽  
Colin J. Yates
Keyword(s):  
Reproductive Biology ◽  
Carrying Capacity ◽  
Seedling Recruitment ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Fire Return Interval ◽  
Viability Analysis ◽  
Return Interval ◽  
Western Australian

Calytrix breviseta Lindl. subsp. breviseta is a critically endangered, obligate-seeder shrub within fire-prone kwongan of south-west Western Australia. Little is known about the species’ reproductive biology and how threatening processes, particularly altered fire regimes and exotic species invasion, will impact the long-term viability of the species. This study aims to elucidate the species’ reproductive biology and patterns of seedling recruitment during succession after fire. The effects of changes to the fire return interval and exotic species invasion on the long-term viability of the species is also described. The species exhibits abundant recruitment following fire and the application of a smoke treatment significantly improves germination, similar to many other Western Australian shrubs. However, significant inter-fire recruitment was observed up to 10 years following fire, leading to the presence of multi-aged subpopulations, although seedling recruitment was negligible >20 years after fire. The juvenile period is short at 3–4 years to first flowering. Population viability analysis (PVA) predicted that the optimal fire return interval to maintain C. breviseta subsp. breviseta was dependent on the carrying capacity (K) of the community and the number of individuals present. Carrying capacity will be related to site quality and competition from invasive species. PVA showed that if K remains high, then the optimal fire return interval is ~15–20 years, but under lower carrying capacity, (i.e. weed competition) fires decrease the likelihood of population survival.

Fuel treatment effects on modeled landscape-level fire behavior in the northern Sierra Nevada

2010 ◽  
Vol 40 (9) ◽  
pp. 1751-1765 ◽  
Author(s):  
Jason J. Moghaddas ◽  
Brandon M. Collins ◽  
Kurt Menning ◽  
Emily E.Y. Moghaddas ◽  
Scott L. Stephens
Keyword(s):  
Sierra Nevada ◽  
Fire Behavior ◽  
Treatment Strategies ◽  
Weather Conditions ◽  
Fire Regimes ◽  
Flame Length ◽  
Fuel Treatment ◽  
Burn Probability ◽  
Pre Treatment ◽  
Landscape Level

Across the western United States, decades of fire exclusion combined with past management history have contributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group selection treatments on crown fire potential, flame length, and conditional burn probabilities across 11 land allocation types for an 18 600 ha study area within the northern Sierra Nevada, California. Fire modeling was completed using FlamMap and FARSITE based on landscape files developed with high-resolution aerial (IKONOS) imagery, ground-based plot data, and integrated data from ARCFUELS and the Forest Vegetation Simulator. Under modeled 97th percentile weather conditions, average conditional burn probability was reduced between pre- and post-treatment landscapes. A more detailed simulation of a hypothetical fire burning under fairly severe fire weather, or “problem fire”, revealed a 39% reduction in final fire size for the treated landscape relative to the pre-treatment condition. To modify fire behavior at a landscape level, a combination of fuel treatment strategies that address topographic location, land use allocations, vegetation types, and fire regimes is needed.

scholarly journals A model comparison of fire return interval impacts on carbon and species dynamics in a southeastern U.S. pineland

Ecosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
Author(s):  
Steven A. Flanagan ◽  
J. Kevin Hiers ◽  
Mac A. Callaham ◽  
Scott Goodrick ◽  
Joseph J. O’Brien ◽  
...  
Keyword(s):  
Model Comparison ◽  
Fire Return Interval ◽  
Return Interval ◽  
Species Dynamics
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