Reply—A re-examination of the effects of fire suppression in the boreal forest

2001 ◽  
Vol 31 (8) ◽  
pp. 1467-1480 ◽  
Author(s):  
P C Ward ◽  
A G Tithecott ◽  
B M Wotton
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Forest Disturbance ◽  
Fire Suppression ◽  
Fire Disturbance ◽  
Fire Size ◽  
Area Burned ◽  
Return Interval ◽  
The Past ◽  
Northwestern Ontario

Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305) presented data that indicated fire suppression activities in Ontario led to reductions in average annual area burned and greater numbers of small fires, compared with what would have been observed in the absence of suppression. Miyanishi and Johnson (K. Miyanishi and E.A. Johnson. 2001. Can. J. For. Res. 31: 1462–1466) have questioned aspects of that report, suggesting that the evidence does not demonstrate that suppression influences fire size or frequency. Fire-history studies in Ontario's forests and recent fire disturbance records do show that the fire-return interval has lengthened considerably in Ontario's protected forest since pre-suppression times. Analysis of forest inventory age-class distributions also reflect a reduction in overall forest disturbance rates in the past 40 years. Average annual burn fractions (ABF) calculated for protected and unprotected forests in northwestern Ontario for the period 1976-2000 show an ABF of 1.11% in the unprotected forest and only 0.34% in the protected forest. There is clear evidence that fire suppression in Ontario contains many fires at small sizes that would have otherwise grown to larger sizes, and reduces the overall average annual area burned in the protected forest.

scholarly journals 8,000 years of climate, vegetation, fire and land-use dynamics in the thermo-mediterranean vegetation belt of northern Sardinia (Italy)

2021 ◽  
Author(s):  
Tiziana Pedrotta ◽  
Erika Gobet ◽  
Christoph Schwörer ◽  
Giorgia Beffa ◽  
Christoph Butz ◽  
...  
Keyword(s):  
Land Use ◽  
Bronze Age ◽  
Fire History ◽  
Vegetation History ◽  
Juglans Regia ◽  
Fire Disturbance ◽  
Lake Productivity ◽  
The Past ◽  
Evergreen Oak ◽  
The Bronze Age

AbstractKnowledge about the vegetation history of Sardinia, the second largest island of the Mediterranean, is scanty. Here, we present a new sedimentary record covering the past ~ 8,000 years from Lago di Baratz, north-west Sardinia. Vegetation and fire history are reconstructed by pollen, spores, macrofossils and charcoal analyses and environmental dynamics by high-resolution element geochemistry together with pigment analyses. During the period 8,100–7,500 cal bp, when seasonality was high and fire and erosion were frequent, Erica arborea and E. scoparia woodlands dominated the coastal landscape. Subsequently, between 7,500 and 5,500 cal bp, seasonality gradually declined and thermo-mediterranean woodlands with Pistacia and Quercus ilex partially replaced Erica communities under diminished incidence of fire. After 5,500 cal bp, evergreen oak forests expanded markedly, erosion declined and lake levels increased, likely in response to increasing (summer) moisture availability. Increased anthropogenic fire disturbance triggered shrubland expansions (e.g. Tamarix and Pistacia) around 5,000–4,500 cal bp. Subsequently around 4,000–3,500 cal bp evergreen oak-olive forests expanded massively when fire activity declined and lake productivity and anoxia reached Holocene maxima. Land-use activities during the past 4,000 years (since the Bronze Age) gradually disrupted coastal forests, but relict stands persisted under rather stable environmental conditions until ca. 200 cal bp, when agricultural activities intensified and Pinus and Eucalyptus were planted to stabilize the sand dunes. Pervasive prehistoric land-use activities since at least the Bronze Age Nuraghi period included the cultivation of Prunus, Olea europaea and Juglans regia after 3,500–3,300 cal bp, and Quercus suber after 2,500 cal bp. We conclude that restoring less flammable native Q. ilex and O. europaea forest communities would markedly reduce fire risk and erodibility compared to recent forest plantations with flammable non-native trees (e.g. Pinus, Eucalyptus) and xerophytic shrubland (e.g. Cistus, Erica).

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.

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.

scholarly journals An overview of LEOPARDS: The Level of Protection Analysis System

1999 ◽  
Vol 75 (4) ◽  
pp. 615-621 ◽  
Author(s):  
R. S. McAlpine ◽  
K. G. Hirsch
Keyword(s):  
Fire Management ◽  
Fire Suppression ◽  
Primary Component ◽  
Fire Occurrence ◽  
Resource Information ◽  
Area Burned ◽  
Occurrence Data ◽  
Management Policies ◽  
Analysis System ◽  
Management Issues

The Level of Protection Analysis System (LEOPARDS) allows the structured assessment of the outcomes and costs associated with alternative fire management policies, budgets, and suppression resource mixes. Its primary component is a deterministic, spatially conscious simulation model that emulates the daily fire suppression activities of a provincial fire management agency. Inputs for the model include historical fire weather and fire occurrence data, land-use objectives and operational rules, and infrastructure and suppression resource information. The model estimates physical outcomes (e.g., response time, number of escaped fires, area burned), fiscal results (e.g., fixed and variable costs), and resource utilization information. LEOPARDS has been used to address a number of strategic fire management issues in the province of Ontario and is being assessed for use in other parts of Canada.

Location, timing and extent of wildfire vary by cause of ignition

2015 ◽  
Vol 24 (1) ◽  
pp. 37 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
Management Strategy ◽  
Southern California ◽  
Fire Management ◽  
Fire Suppression ◽  
The Other ◽  
Area Burned ◽  
Spatial And Temporal Distributions ◽  
Prevention Programmes ◽  
Management Approaches ◽  
Fire Extent

The increasing extent of wildfires has prompted investigation into alternative fire management approaches to complement the traditional strategies of fire suppression and fuels manipulation. Wildfire prevention through ignition reduction is an approach with potential for success, but ignitions result from a variety of causes. If some ignition sources result in higher levels of area burned, then ignition prevention programmes could be optimised to target these distributions in space and time. We investigated the most common ignition causes in two southern California sub-regions, where humans are responsible for more than 95% of all fires, and asked whether these causes exhibited distinct spatial or intra-annual temporal patterns, or resulted in different extents of fire in 10–29-year periods, depending on sub-region. Different ignition causes had distinct spatial patterns and those that burned the most area tended to occur in autumn months. Both the number of fires and area burned varied according to cause of ignition, but the cause of the most numerous fires was not always the cause of the greatest area burned. In both sub-regions, power line ignitions were one of the top two causes of area burned: the other major causes were arson in one sub-region and power equipment in the other. Equipment use also caused the largest number of fires in both sub-regions. These results have important implications for understanding why, where and how ignitions are caused, and in turn, how to develop strategies to prioritise and focus fire prevention efforts. Fire extent has increased tremendously in southern California, and because most fires are caused by humans, ignition reduction offers a potentially powerful management strategy, especially if optimised to reflect the distinct spatial and temporal distributions in different ignition causes.

scholarly journals DEFINICIÓN DE LA ÉPOCA DE INCENDIOS FORESTALES EN UN CONTEXTO MULTIVARIADO

FLORESTA ◽  
2004 ◽  
Vol 34 (2) ◽  
Author(s):  
Marcos Pedro Ramos Rodríguez ◽  
Yudisnelvis González Menzonet
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Fire Season ◽  
Fire Statistics ◽  
Area Burned ◽  
Forest Fire Management ◽  
Santiago De Cuba ◽  
The Mean ◽  
Definition Of ◽  
Del Rio

En este trabajo se presenta un acercamiento a la definición de la época de incendios forestales en un contexto multivariado como contribución a la planificación del manejo de los mismos. El método se basa en seleccionar las variables que expresen el comportamiento histórico de los incendios cada mes durante un periodo de años determinado. Entre estas variables se encuentran la densidad de incendios y la densidad de afectaciones, la media y la mediana del área quemada por incendio, el número de grandes incendios y la máxima área quemada por un incendio. Usando sistemas estadísticos pueden agruparse los meses con técnicas de análisis de cluster y la época de incendio puede ser definida. El método se aplicó en las provincias Santiago de Cuba y Pinar del Río, ubicadas en las regiones oriental y occidental de Cuba respectivamente. Se utilizaron estadísticas de incendios del periodo 1997 - 2002. DEFINITION OF THE FIRE SEASON IN A MULTIVARIATE CONTEXT Abstract In this work an approach to the definition of the fire season in a multivariate context is presented. It is a contribution to the forest fire management. The method is based on selecting the variables that express the fire history every month during a certain period of years. Among these variables there are the density of fires and the density of affectations, the mean and median of the area burned by fire, the number of big fires and the maximum area burned by a fire. To group the months is used the cluster analysis technical and it allows to define the fire season. The method was applied in the provinces of Santiago de Cuba and Pinar del Río, located in the regions oriental and western of Cuba respectively. Fire statistics from the period 1997/2002 were used.

Recent Changes in Annual Area Burned in Interior Alaska: The Impact of Fire Management

2015 ◽  
Vol 19 (5) ◽  
pp. 1-17 ◽  
Author(s):  
M. P. Calef ◽  
A. Varvak ◽  
A. D. McGuire ◽  
F. S. Chapin ◽  
K. B. Reinhold
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Fire Management ◽  
Fire Suppression ◽  
Regional Climate ◽  
Temporal Analysis ◽  
Fire Service ◽  
Area Burned ◽  
The Pacific ◽  
The Impact

Abstract The Alaskan boreal forest is characterized by frequent extensive wildfires whose spatial extent has been mapped for the past 70 years. Simple predictions based on this record indicate that area burned will increase as a response to climate warming in Alaska. However, two additional factors have affected the area burned in this time record: the Pacific decadal oscillation (PDO) switched from cool and moist to warm and dry in the late 1970s and the Alaska Fire Service instituted a fire suppression policy in the late 1980s. In this paper a geographic information system (GIS) is used in combination with statistical analyses to reevaluate the changes in area burned through time in Alaska considering both the influence of the PDO and fire management. The authors found that the area burned has increased since the PDO switch and that fire management drastically decreased the area burned in highly suppressed zones. However, the temporal analysis of this study shows that the area burned is increasing more rapidly in suppressed zones than in the unsuppressed zone since the late 1980s. These results indicate that fire policies as well as regional climate patterns are important as large-scale controls on fires over time and across the Alaskan boreal forest.

Talking about fire: Pikangikum First Nation elders guiding fire management

2010 ◽  
Vol 40 (12) ◽  
pp. 2290-2301 ◽  
Author(s):  
Andrew M. Miller ◽  
Iain J. Davidson-Hunt ◽  
Paddy Peters
Keyword(s):  
Fire Management ◽  
Forest Disturbance ◽  
First Nation ◽  
Research Strategies ◽  
Management Planning ◽  
Northwestern Ontario ◽  
Controlled Burning ◽  
Management Policies ◽  
Landscape Scales ◽  
In Fire

In this paper, we present how elders of Pikangikum First Nation in northwestern Ontario have drawn upon their knowledge and values associated with fire to engage in fire management planning for 1.3 million hectares of their traditional boreal forest territory. Over a period of 18 months, we engaged in collaborative research strategies that included interviews, visits to historic fire sites, and community meetings with Ontario Ministry of Natural Resources (OMNR) to document the elders’ understandings of fire behaviour, forest disturbance and renewal cycles, traditional controlled burning practices, and perspectives on current fire management policies. The elders demonstrated the relevance of their knowledge of fire to contemporary planning efforts affecting woodland caribou habitat and fire management at site and landscape scales within their territory. We identified three themes and six recommendations that elders confirmed as priorities for future fire management planning. The three themes include (i) the need for continuing dialogue for fire management planning with OMNR, (ii) extending traditional teachings of fire safety to community youth, and (iii) the desire to re-engage in fire management using traditional processes.

Comment—A re-examination of the effects of fire suppression in the boreal forest

2001 ◽  
Vol 31 (8) ◽  
pp. 1462-1466 ◽  
Author(s):  
K Miyanishi ◽  
E A Johnson
Keyword(s):  
Boreal Forest ◽  
Fire Management ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Stand Age ◽  
Reliable Estimate ◽  
Fire Size ◽  
Fire Cycle ◽  
Large Fires ◽  
In Fire

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.

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.

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