Fuel fragmentation and fire size distributions in managed and unmanaged boreal forests in the province of Saskatchewan, Canada

Analyzing Wildfires and their Socio-economic Factors in Sardinia

10.21203/rs.3.rs-1131301/v1 ◽

2021 ◽

Author(s):

Laura Serra ◽

Claudio Detotto ◽

Marco Vannini

Keyword(s):

Public Lands ◽

Local Communities ◽

Time Span ◽

Burned Area ◽

Economic Factors ◽

Size Distributions ◽

Fire Size ◽

Spatio Temporal ◽

Socio Economic Factors

Abstract In the last decades, wildfire hazards have increased to dangerous levels, becoming the focus of debate among policymakers both at the local and national levels. This paper proposes a Spatio-temporal approach to study the determinants of fire size distributions taking Sardinia as a case study in the time span 1998-2009. Special attention is devoted to socioeconomic factors of local communities where wildfires occurred. The main finding of this study is that the proportion of public lands in a given municipality tends to mitigate the extent of the burned area. In addition, communities with a higher percentage of people employed in the primary sector are less likely to experience large burned extents.

Download Full-text

Landscape composition influences local pattern of fire size in the eastern Canadian boreal forest: role of weather and landscape mosaic on fire size distribution in mixedwood boreal forest using the Prescribed Fire Analysis System

International Journal of Wildland Fire ◽

10.1071/wf09112 ◽

2010 ◽

Vol 19 (8) ◽

pp. 1099 ◽

Cited By ~ 16

Author(s):

Christelle Hély ◽

C. Marie-Josée Fortin ◽

Kerry R. Anderson ◽

Yves Bergeron

Keyword(s):

Boreal Forest ◽

Prescribed Fire ◽

Boreal Forests ◽

Weather Conditions ◽

Landscape Composition ◽

Burned Area ◽

Fire Size ◽

Fire Cycle ◽

Area Burned ◽

Analysis System

Wildfire simulations were carried out using the Prescribed Fire Analysis System (PFAS) to study the effect of landscape composition on fire sizes in eastern Canadian boreal forests. We used the Lake Duparquet forest as reference, plus 13 forest mosaic scenarios whose compositions reflected lengths of fire cycle. Three fire weather risks based on duff moisture were used. We performed 100 simulations per risk and mosaic, with topography and hydrology set constant for the reference. Results showed that both weather and landscape composition significantly influenced fire sizes. Weather related to fire propagation explained almost 79% of the variance, while landscape composition and weather conditions for ignition explained ∼14 and 2% respectively. In terms of landscape, burned area increased with increasing presence of shade-tolerant species, which are related to long fire cycles. Comparisons among the distributions of cumulated area burned from scenarios plus those from the Société de Protection des Forêts contre le Feu database archives showed that PFAS simulated realistic fire sizes using the 80–100% class of probable fire extent. Future analyses would best be performed on a larger region as the limited size of the study area could not capture fires larger than 11 000 ha, which represent 3% of fires but 65% of the total area burned at the provincial scale.

Download Full-text

Wilderness shapes contemporary fire size distributions across landscapes of the western United States

Ecosphere ◽

10.1890/es12-00257.1 ◽

2013 ◽

Vol 4 (1) ◽

pp. art15 ◽

Cited By ~ 16

Author(s):

Sandra L. Haire ◽

Kevin McGarigal ◽

Carol Miller

Keyword(s):

United States ◽

Western United States ◽

Size Distributions ◽

Fire Size

Download Full-text

Highlighting Biome-Specific Sensitivity of Fire Size Distributions to Time-Gap Parameter Using a New Algorithm for Fire Event Individuation

Remote Sensing ◽

10.3390/rs8080663 ◽

2016 ◽

Vol 8 (8) ◽

pp. 663 ◽

Cited By ~ 11

Author(s):

Duarte Oom ◽

Pedro Silva ◽

Ioannis Bistinas ◽

José Pereira

Keyword(s):

Size Distributions ◽

Fire Size ◽

Fire Event ◽

Specific Sensitivity ◽

Time Gap ◽

Gap Parameter

Download Full-text

Smoke aerosol properties and ageing effects for northern temperate and boreal regions derived from AERONET source and age attribution

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-7929-2015 ◽

2015 ◽

Vol 15 (14) ◽

pp. 7929-7943 ◽

Cited By ~ 10

Author(s):

T. Nikonovas ◽

P. R. J. North ◽

S. H. Doerr

Keyword(s):

Optical Properties ◽

Land Cover ◽

Boreal Forests ◽

Tree Cover ◽

Particulate Emissions ◽

Climate Modelling ◽

Size Distributions ◽

Hysplit Model ◽

Land Cover Types ◽

Ageing Effects

Abstract. Particulate emissions from wildfires impact human health and have a large but uncertain effect on climate. Modelling schemes depend on information about emission factors, emitted particle microphysical and optical properties and ageing effects, while satellite retrieval algorithms make use of characteristic aerosol models to improve retrieval. Ground-based remote sensing provides detailed aerosol characterisation, but does not contain information on source. Here, a method is presented to estimate plume origin land cover type and age for AERONET aerosol observations, employing trajectory modelling using the HYSPLIT model, and satellite active fire and aerosol optical thickness (AOT) observations from Moderate Resolution Imaging Spectroradiometer (MODIS) and Along Track Scanning Radiometer (AATSR). It is applied to AERONET stations located in or near northern temperate and boreal forests for the period 2002–2013. The results from 629 fire attributions indicate significant differences in size distributions and particle optical properties between different land cover types and plume age. Smallest fine mode median radius (Rfv) are attributed to plumes from cropland and/or natural vegetation mosaic (0.143 μm) and grassland (0.157 μm) fires. North American evergreen needleleaf forest emissions show a significantly smaller Rfv (0.164 μm) than plumes from Eurasian mixed forests (0.193 μm) and plumes attributed to the land cover types with sparse tree cover – open shrubland (0.185 μm) and woody savannas (0.184 μm). The differences in size distributions are related to inferred variability in plume concentrations between the land cover types. Significant differences are observed between day and night emissions, with daytime emissions showing larger particle sizes. Smoke is predominantly scattering for all of the classes with median single scattering albedo at 440 nm (SSA(440)) values close to 0.95 except the cropland emissions which have an SSA(440) value of 0.9. Plumes aged for 4 days or older have median Rfv larger by ~0.02 μm compared to young smoke. Differences in size were consistent with a decrease in the Ångström Exponent and increase in the asymmetry parameter. Only an insignificant increase in SSA(λ) with ageing was found.

Download Full-text

Spatiotemporal prediction of wildfire extremes with Bayesian finite sample maxima

10.1101/384115 ◽

2018 ◽

Cited By ~ 1

Author(s):

Maxwell B. Joseph ◽

Matthew W. Rossi ◽

Nathan P. Mietkiewicz ◽

Adam L. Mahood ◽

Megan E. Cattau ◽

...

Keyword(s):

United States ◽

Negative Binomial ◽

Nonlinear Effects ◽

Predictive Distribution ◽

Fire Frequency ◽

Size Distributions ◽

Finite Sample ◽

Fire Size ◽

Posterior Predictive Distribution ◽

Data Set

AbstractWildfires are becoming more frequent in parts of the globe, but predicting where and when wildfires occur remains difficult. To predict wildfire extremes across the contiguous United States, we integrate a 30 year wildfire record with meteorological and housing data in spatiotemporal Bayesian statistical models with spatially varying nonlinear effects. We compared different distributions for the number and sizes of large fires to generate a posterior predictive distribution based on finite sample maxima for extreme events (the largest fires over bounded spatiotemporal domains). A zero-inflated negative binomial model for fire counts and a lognormal model for burned areas provided the best performance. This model attains 99% interval coverage for the number of fires and 93% coverage for fire sizes over a six year withheld data set. Dryness and air temperature strongly predict extreme wildfire probabilities. Housing density has a hump-shaped relationship with fire occurrence, with more fires occurring at intermediate housing densities. Statistically, these drivers affect the chance of an extreme wildfire in two ways: by altering fire size distributions, and by altering fire frequency, which influences sampling from the tails of fire size distributions. We conclude that recent extremes should not be surprising, and that the contiguous United States may be on the verge of even larger wildfire extremes.

Download Full-text

Spatial distribution of mean fire size and occurrence in eastern Canada: influence of climate, physical environment and lightning strike density

International Journal of Wildland Fire ◽

10.1071/wf18220 ◽

2019 ◽

Vol 28 (12) ◽

pp. 927 ◽

Cited By ~ 1

Author(s):

Jeanne Portier ◽

Sylvie Gauthier ◽

Yves Bergeron

Keyword(s):

Environmental Factors ◽

Moisture Content ◽

Boreal Forests ◽

Fire Regime ◽

Fire Regimes ◽

Lightning Strike ◽

Annual Number ◽

Fire Size ◽

Eastern Canada ◽

Deep Layers

In Canada, recent catastrophic wildfire events raised concern from governments and communities. As climate change is expected to increase fire activity in boreal forests, the need for a better understanding of fire regimes is becoming urgent. This study addresses the 1972–2015 spatial distributions of fire cycles, mean fire size (FireSz) and mean fire occurrence (mean annual number of fires per 100000ha, FireOcc) in eastern Canada. The objectives were to determine (1) the spatial variability of fire-regime attributes, (2) the capacity of FireSz and FireOcc to distinguish homogeneous fire zones and (3) the environmental factors driving FireSz and FireOcc, with some emphasis on lightning strikes. Fire cycles, FireSz and FireOcc greatly varied throughout the study area. Even within homogeneous fire zones, FireSz and FireOcc were highly variable. FireSz was controlled by moisture content in deep layers of the soil and by surficial deposits, whereas FireOcc was controlled by moisture content in top layers of the soil and by relief. The lack of a relationship between FireOcc and lightning-strike density suggested that the limiting effect of lightning-strike density on FireOcc could be operating only under certain circumstances, when interacting with other environmental factors.

Download Full-text