Historical reconstructions of California wildfires vary by data source

2016 ◽  
Vol 25 (12) ◽  
pp. 1221 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
United States ◽  
Fire History ◽  
Fire Suppression ◽  
Resource Assessment ◽  
Fire Frequency ◽  
The State ◽  
Annual Reports ◽  
Spatially Explicit ◽  
California Department ◽  
Area Burned

Historical data are essential for understanding how fire activity responds to different drivers. It is important that the source of data is commensurate with the spatial and temporal scale of the question addressed, but fire history databases are derived from different sources with different restrictions. In California, a frequently used fire history dataset is the State of California Fire and Resource Assessment Program (FRAP) fire history database, which circumscribes fire perimeters at a relatively fine scale. It includes large fires on both state and federal lands but only covers fires that were mapped or had other spatially explicit data. A different database is the state and federal governments’ annual reports of all fires. They are more complete than the FRAP database but are only spatially explicit to the level of county (California Department of Forestry and Fire Protection – Cal Fire) or forest (United States Forest Service – USFS). We found substantial differences between the FRAP database and the annual summaries, with the largest and most consistent discrepancy being in fire frequency. The FRAP database missed the majority of fires and is thus a poor indicator of fire frequency or indicators of ignition sources. The FRAP database is also deficient in area burned, especially before 1950. Even in contemporary records, the huge number of smaller fires not included in the FRAP database account for substantial cumulative differences in area burned. Wildfires in California account for nearly half of the western United States fire suppression budget. Therefore, the conclusions about data discrepancies and the implications for fire research are of broad importance.

Using simulation to map fire regimes: an evaluation of approaches, strategies, and limitations

2003 ◽  
Vol 12 (4) ◽  
pp. 309 ◽  
Author(s):  
Robert E. Keane ◽  
Geoffrey J. Cary ◽  
Russell Parsons
Keyword(s):  
Geographical Information Systems ◽  
Fire History ◽  
Fire Regime ◽  
Wildland Fire ◽  
Fire Regimes ◽  
Simulation Modelling ◽  
Fire Frequency ◽  
Geographical Information ◽  
Spatially Explicit ◽  
Eastern Australia

Spatial depictions of fire regimes are indispensable to fire management because they portray important characteristics of wildland fire, such as severity, intensity, and pattern, across a landscape that serves as important reference for future treatment activities. However, spatially explicit fire regime maps are difficult and costly to create requiring extensive expertise in fire history sampling, multivariate statistics, remotely sensed image classification, fire behaviour and effects, fuel dynamics, landscape ecology, simulation modelling, and geographical information systems (GIS). This paper first compares three common strategies for predicting fire regimes (classification, empirical, and simulation) using a 51�000�ha landscape in the Selway-Bitterroot Wilderness Area of Montana, USA. Simulation modelling is identified as the best overall strategy with respect to developing temporally deep spatial fire patterns, but it has limitations. To illustrate these problems, we performed three simulation experiments using the LANDSUM spatial model to determine the relative importance of (1) simulation time span; (2) fire frequency parameters; and (3) fire size parameters on the simulation of landscape fire return interval. The model used to simulate fire regimes is also very important, so we compared two spatially explicit landscape fire succession models (LANDSUM and FIRESCAPE) to demonstrate differences between model predictions and limitations of each on a neutral landscape. FIRESCAPE was developed for simulating fire regimes in eucalypt forests of south-eastern Australia. Finally, challenges for future simulation and fire regime research are presented including field data, scale, fire regime variability, map obsolescence, and classification resolution.

Fire regimes and their correlates in the Darwin region of northern Australia

2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker
Keyword(s):  
Fire History ◽  
Ad Hoc ◽  
Fire Regime ◽  
Negative Impact ◽  
Fire Suppression ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Dry Season ◽  
Generalized Linear Modelling

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.

Effective fire suppression in boreal forests

2005 ◽  
Vol 35 (4) ◽  
pp. 772-786 ◽  
Author(s):  
S G Cumming
Keyword(s):  
Boreal Forests ◽  
Regression Models ◽  
Fire History ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Operational Effectiveness ◽  
Logistic Regression Models ◽  
Area Burned ◽  
Large Fires ◽  
Northeastern Alberta

Fire suppression is (functionally) effective insofar as it reduces area burned. In North American boreal forests, fire regimes and historical records are such that this effect cannot be detected or estimated directly. I present an indirect approach, proceeding from the practice of initial attack (IA), which is intended to limit the proportion of "large" fires. I analysed IA's (operational) effectiveness by a controlled retrospective study of fire-history data for an approximately 86 000 km2 region of boreal forest in northeastern Alberta, Canada, from 1968 to 1998 (31 years). Over this interval, various improvements to IA practice, including a 1983 change in management strategy, created a natural experiment. I tested the results with multiple logistic regression models of the annual probabilities of a fire becoming larger than 3 and 200 ha. Annual fire counts (Nt) were a surrogate for fire weather and peak daily counts within years (arrival load). Measured by odds ratios, mean IA effectiveness against 3- and 200-ha fires increased in 1983 by factors of 2.02 (95% CI = 1.70–2.40) and 2.41 (95% CI = 1.69–3.45), respectively. Prior to 1983, the functional response to Nt was consistent with saturation of IA capacity at high arrival loads. From 1983–1998, effectiveness was independent of Nt. I introduce the proportional reduction in area burned (impact) as a measure of functional effectiveness and state conditions under which it can be estimated from the regression models. Over 1983–1998, if suppressed and actual fires were comparable, relative IA impact ([Formula: see text]) was 0.58 (95% CI = 0.34–0.74) and area burned was reduced by 457 500 ha. If fires larger than 1 × 105, 1 × 104, or 1 × 103 ha are assumed to be unpreventable, [Formula: see text] declines to 0.46, 025, or 0.08, respectively, but there is no evidence this is the case.

Changes in forest fire frequency in Kootenay National Park, Canadian Rockies

1990 ◽  
Vol 68 (8) ◽  
pp. 1763-1767 ◽  
Author(s):  
Alan M. Masters
Keyword(s):  
Forest Fire ◽  
Rocky Mountains ◽  
National Park ◽  
Fire History ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Ice Age ◽  
Distribution Analysis ◽  
Fire Cycle ◽  
Time Since Fire

Time-since-fire distribution analysis is used to estimate forest fire frequency for the 1400 km2 Kootenay National Park, British Columbia, located on the west slope of the Rocky Mountains. The time-since-fire distribution indicates three periods of different fire frequency: 1988 to 1928, 1928 to 1788, and before 1788. The fire cycle for the park was > 2700 years for 1988 to 1928, 130 years between 1928 and 1788, and 60 years between 1778 and 1508. Longer fire cycles after 1788 and 1928 may be due, respectively, to cool climate associated with the Little Ice Age and a recent period of higher precipitation. Contrary to some fire history investigations in the region, neither a fire suppression policy since park establishment in 1919, nor the completion of the Windermere Highway through the park in 1923 appear to have changed the fire frequency from levels during pre-European occupation. Spatial partitioning of the time-since-fire distribution was unsuccessful. No relationship was found between elevation or aspect and fire frequency. Key words: fire cycle, Rocky Mountains, climate change.

Land Zoning Based on Fire History

1997 ◽  
Vol 7 (3) ◽  
pp. 249 ◽  
Author(s):  
G Bovio ◽  
A Camia
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Fire Frequency ◽  
Basic Unit ◽  
Spread Rate ◽  
Analysis Techniques ◽  
Area Burned ◽  
Management Plans ◽  
Fire Planning

An approach to land zoning for fire planning purposes through classification of geographical units referred to as Basic Units - in a multivariate context is proposed. The method, developed for large areas, employs a few statistics computed from historical fire data, that were selected with the aim of depicting a ''fire history profile'' of each Basic Unit. The statistics were chosen in order to describe different aspects, such as fire frequency, fire continuity, average and maximum area burned and average area spread rate of fires. Using the computed statistics as variables, the Basic Units can be aggregated with cluster analysis techniques and classes can be defined, each class of Basic Units representing a land zone with a specific mean fire history profile. Fire management decisions can be tailored according to the properties of clusters. The method was successfully applied for supporting fire management plans in two Regions of Northern Italy, where the Basic Units were chosen with an administrative criterion.

Frequency and season of fires varies with distance from settlement and grass composition in Eucalyptus miniata savannas of the Darwin region of northern Australia

2009 ◽  
Vol 18 (1) ◽  
pp. 61 ◽  
Author(s):  
Louis P. Elliott ◽  
Donald C. Franklin ◽  
David M. J. S. Bowman
Keyword(s):  
Fire History ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Dry Season ◽  
Perennial Grasses ◽  
Northern Australia ◽  
Landsat Images ◽  
Fire Cycle ◽  
Annual Grasses ◽  
Key Issues

In savanna environments, fire and grass are inextricably linked by feedback loops. In the Darwin area of northern Australia, flammable tall annual grasses of the genus Sarga (previously Sorghum1) have been implicated in a savanna fire-cycle. We examined the relationship between fire history, the grass layer and distance from settlement using LANDSAT images and plot-based surveys. Areas more than 500 m from settlement were burnt almost twice as often, the additional fires being concentrated late in the dry season and in areas dominated by annual Sarga and even more so where dominated by short annual grasses. Grass cover was a stronger correlate of fire frequency than grass biomass, the two showing a non-linear relationship. Sites dominated by short annual grasses had similar cover to, but markedly lower biomass than those dominated by annual Sarga or perennial grasses. Our results reflect the success of fire suppression in the vicinity of settlements, but little effective management of late dry-season wildfires in remoter areas. We evaluate several hypotheses for the association of frequent fire with annual grasses regardless of their growth form and conclude that fuel connectivity and possibly other fuel characteristics are key issues worthy of further investigation.

Fire frequency for the transitional mixedwood forest of Timiskaming, Quebec, Canada

2005 ◽  
Vol 35 (3) ◽  
pp. 656-666 ◽  
Author(s):  
Daniel J Grenier ◽  
Yves Bergeron ◽  
Daniel Kneeshaw ◽  
Sylvie Gauthier
Keyword(s):  
Fire History ◽  
Fire Suppression ◽  
Sampling Strategy ◽  
Fire Frequency ◽  
Management Approach ◽  
Land Use Patterns ◽  
Temporal Shift ◽  
Fire Cycle ◽  
Old Growth Forest ◽  
Time Required

Fire history was reconstructed for a 2500-km2 area at the interface between the boreal coniferous and northern hardwood forests of southwestern Quebec. The fire cycle, the time required for an area equal to the study site to burn once over, was described using a random sampling strategy that included dendrochronological techniques in conjunction with provincial and national government archival data. Physiographic elements were not found to spatially influence fire frequency; however, human land-use patterns were observed to significantly affect the fire frequency. A temporal shift in fire frequency was also detected, which coincided with the period of Euro-Canadian colonization and known extreme dry years for the study site. Additionally, a fire-free period was identified in the most recent times that could be associated with fire suppression and climate change. The estimated cycles (approx. 188–314 years) for the southeastern section of the study area were thought to better represent the natural cycles for this transition zone as a result of less anthropogenic influence. The importance of gap-type dynamics becomes evident with the increased presence of old-growth forest, given the derived fire cycle estimations for the region. Even-aged management with short rotations, consequently, is questioned because fire cycle estimations suggest more complex harvest systems using an ecosystem management approach.

Fire history of the San Francisco East Bay region and implications for landscape patterns

2005 ◽  
Vol 14 (3) ◽  
pp. 285 ◽  
Author(s):  
Jon E. Keeley
Keyword(s):  
Native Americans ◽  
20Th Century ◽  
San Francisco ◽  
Fire History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Landscape Patterns ◽  
East Bay ◽  
Anthropogenic Fires

The San Francisco East Bay landscape is a rich mosaic of grasslands, shrublands and woodlands that is experiencing losses of grassland due to colonization by shrubs and succession towards woodland associations. The instability of these grasslands is apparently due to their disturbance-dependent nature coupled with 20th century changes in fire and grazing activity. This study uses fire history records to determine the potential for fire in this region and for evidence of changes in the second half of the 20th century that would account for shrubland expansion. This region has a largely anthropogenic fire regime with no lightning-ignited fires in most years. Fire suppression policy has not excluded fire from this region; however, it has been effective at maintaining roughly similar burning levels in the face of increasing anthropogenic fires, and effective at decreasing the size of fires. Fire frequency parallels increasing population growth until the latter part of the 20th century, when it reached a plateau. Fire does not appear to have been a major factor in the shrub colonization of grasslands, and cessation of grazing is a more likely immediate cause. Because grasslands are not under strong edaphic control, rather their distribution appears to be disturbance-dependent, and natural lightning ignitions are rare in the region, I hypothesize that, before the entrance of people into the region, grasslands were of limited extent. Native Americans played a major role in creation of grasslands through repeated burning and these disturbance-dependent grasslands were maintained by early European settlers through overstocking of these range lands with cattle and sheep. Twentieth century reduction in grazing, coupled with a lack of natural fires and effective suppression of anthropogenic fires, have acted in concert to favor shrubland expansion.

Different historical fire–climate patterns in California

2017 ◽  
Vol 26 (4) ◽  
pp. 253 ◽  
Author(s):  
Jon E. Keeley ◽  
Alexandra D. Syphard
Keyword(s):  
20Th Century ◽  
Sierra Nevada ◽  
Climate Models ◽  
The State ◽  
California Department ◽  
Current Season ◽  
Area Burned ◽  
Lower Elevation ◽  
Fire Activity ◽  
Summer Temperatures

The relationship between annual variation in area burned and seasonal temperatures and precipitation was investigated for the major climate divisions in California. Historical analyses showed marked differences in fires on montane and foothill landscapes. Based on roughly a century of data, there are five important lessons on fire–climate relationships in California: (1) seasonal variations in temperature appear to have had minimal influence on area burned in the lower elevation, mostly non-forested, landscapes; (2) temperature has been a significant factor in controlling fire activity in higher elevation montane forests, but this varied greatly with season – winter and autumn temperatures showed no significant effect, whereas spring and summer temperatures were important determinants of area burned; (3) current season precipitation has been a strong controller of fire activity in forests, with drier years resulting in greater area burned on most United States Forest Service (USFS) lands in the state, but the effect of current-year precipitation was decidedly less on lower elevation California Department of Forestry and Fire Protection lands; (4) in largely grass-dominated foothills and valleys the magnitude of prior-year rainfall was positively tied to area burned in the following year, and we hypothesise that this is tied to greater fuel volume in the year following high rainfall. In the southern part of the state this effect has become stronger in recent decades and this likely is due to accelerated type conversion from shrubland to grassland in the latter part of the 20th century; (5) the strongest fire–climate models were on USFS lands in the Sierra Nevada Mountains, and these explained 42–52% of the variation in area burned; however, the models changed over time, with winter and spring precipitation being the primary drivers in the first half of the 20th century, but replaced by spring and summer temperatures after 1960.

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