Large fires, fire effects and the fire-regime concept

2008 ◽  
Vol 17 (6) ◽  
pp. 688 ◽  
Author(s):  
A. Malcolm Gill ◽  
Grant Allan
Keyword(s):  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Suppression ◽  
Wide Spectrum ◽  
Current Trend ◽  
Fire Regimes ◽  
Fire Effects ◽  
Spatial Variables ◽  
Historical Series ◽  
Large Fires

‘Large’ fires may be declared so because of their absolute or relative area. Huge fires – with areas of more than 106 ha (104 km2) have occurred across a wide spectrum of Australian environments and are known on other continents. Such large fires are rare whereas fires with much smaller areas are common. Large fires are initiated by single or multiple ignitions and become large because of some combination of: rapid rates of spread; long ‘life’; merging, and failure of initial suppression operations. Fires as ecological ‘events’ occur within a ‘regime’ – an historical series. Both events and regimes have effects that may be discerned in terms of water, land, air or organisms. What have been regarded as the components of ‘regimes’ have differed between observers, the main issue being whether or not spatial variables need to be included; ‘area’ involvement is briefly addressed. The current trend toward fire-regime control through fuel treatment, including management (prescribed) burning, and fire suppression may be expected to continue. These trends, among others, can be expected to change fire regimes. What is regarded as ‘large’ among fires may change as the planet becomes increasingly human-dominated.

scholarly journals The origins of prescribed burning in Scandinavian forestry: the seminal role of Joel Wretlind in the management of fire-dependent forests

2019 ◽  
Vol 139 (3) ◽  
pp. 393-406
Author(s):  
Sarah Cogos ◽  
Samuel Roturier ◽  
Lars Östlund
Keyword(s):  
Prescribed Fire ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Regimes ◽  
The State ◽  
Natural Processes ◽  
Forest Manager ◽  
Forest District

AbstractIn Sweden, prescribed burning was trialed as early as the 1890s for forest regeneration purposes. However, the origins of prescribed burning in Sweden are commonly attributed to Joel Efraim Wretlind, forest manager in the State Forest district of Malå, Västerbotten County, from 1920 to 1952. To more fully understand the role he played in the development of prescribed burning and the extent of his burning, we examined historical records from the State Forest Company’s archive and Wretlind’s personal archive. The data showed that at least 11,208 ha was burned through prescribed burning between 1921 and 1970, representing 18.7% of the Malå state-owned forest area. Wretlind thus created a new forestry-driven fire regime, reaching, during peak years, extents close to historical fire regimes before the fire suppression era, and much higher than present-day burning. His use of prescribed fire to regenerate forests served as a guide for many other forest managers, spreading to all of northern Sweden during the 1950–1960s. Our analysis of Wretlind’s latest accounts also shows how he stood against the evolutions of modern forestry to defend a forestry system based on the reproduction of natural processes, such as fire.

The contradictory role of fire from the nature conservation perspective

2020 ◽  
Author(s):  
Orsolya Valkó
Keyword(s):  
Nature Conservation ◽  
Land Surface ◽  
Fire History ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Effects ◽  
Negative Effects ◽  
Fire Policy

<p>Fire is a globally relevant natural or anthropogenic phenomenon with a rapidly increasing importance in the era of the climate change. In each year, approximately 4% of the global land surface burns. For effective ecosystem conservation, we need to understand fire regimes, identify potential threats, and also the possibilities in the application of prescribed burning for maintaining ecosystems.</p><p>Here I provide an overview on the contradictory role of fire in nature conservation from two continents with contrasting fire histories, focusing on European and North-American grasslands. I show that the ecological effects of fire depend on the fire regime, fire history, ecosystem properties and the socio-economic environment. Catastrophic wildfires, arson, too frequent or improperly planned human-induced fire often lead to the degradation of the ecosystems, the disappearance of rare plant and animal species, and to the encroachment of weed and invasive species. I illustrate with examples that these negative fire effects act synergistically with the human-induced changes in land use systems.</p><p>I also underline with case studies that in both regions, properly designed and controlled prescribed burning regimes can aid the understanding and managing disturbance-dependent ecosystems. Conservation in these dynamic and complex ecosystems is far more than fencing and hoping to exclude disturbance; but the contrary: disturbance is needed for ecosystem functioning. Therefore, the conservation of dynamic, diverse and functioning ecosystems often require drastic interventions and an unconventional conservation attitude. However, the expanding urban-wildlife interface makes the application of prescribed burning challenging worldwide. A major message for the future is about fire policy: it is crucial to moderate the negative effects of fire, however, properly designed prescribed burning should be used as a tool for managing and conserving disturbance-dependent ecosystems.</p>

scholarly journals The recent fire history of the Table Mountain National Park and implications for fire management

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Greg G. Forsyth ◽  
Brian W. Van Wilgen
Keyword(s):  
National Park ◽  
Fire History ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Weather Conditions ◽  
Fire Regimes ◽  
Management Interventions ◽  
Table Mountain ◽  
Wide Range ◽  
Large Fires

This paper provides an assessment of fire regimes in the Table Mountain National Park over the past four decades. We compiled a GIS database of all fires between 1970 and 2007 and analysed the fire regime in terms of the frequency, season and size of fires and the relationship between fire occurrence and fire weather. Most fires (90.5% of area burnt) occurred in summer and autumn, the ecologically acceptable season for fires. However, mean fire return intervals declined by 18.1 years, from 31.6 to 13.5 years, between the first and last decades of the record respectively. The area subjected to short (≤ six years) intervals between fires covered > 16% of the park in the last two decades of the record, compared to ~ 4% in the first two decades. A relatively small number of large fires dominated in terms of area burnt. Of the 373 fires recorded, 40 fires > 300 ha burnt 75% of the area, while 216 fires < 25 ha burnt 3.4% of the area. Fires occurred under a wide range of weather conditions, but large fires were restricted to periods of high fire danger. Prescribed burning was a relatively unimportant cause of fires, and most (> 85%) of the area burnt in wildfires. Areas subjected to short fire return intervals should be considered for management interventions. These could include the re-establishment of extirpated fire-sensitive species, the clearing of invasive alien plants and increased precautions for the prevention or rapid suppression of future accidental fires.

scholarly journals Fire regimes, biodiversity conservation and prescribed-burning programs

2012 ◽  
Vol 124 (1) ◽  
pp. 1 ◽  
Author(s):  
A. Malcolm Gill
Keyword(s):  
Biodiversity Conservation ◽  
Working Conditions ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Regimes ◽  
Royal Commission ◽  
Vegetation Types ◽  
Protection Of Life ◽  
Conservation Of Biodiversity ◽  
Safe Working

In the trend towards the domestication, or taming, of fire regimes in Victoria, Australia, the level of prescribed burning has been stepped up due to a recommendation from the 2009 Victorian Bushfires Royal Commission. While prescribed burning programs may be instituted for a number of reasons, especially the protection of life and property, they have consequences for the conservation of biodiversity. Not all vegetation types can be prescribed burned because the weather does not always allow it to occur under safe working conditions; where prescribed burning programs are carried out, unplanned fires may still occur. Thus, the general issue is the effect on biodiversity of both prescribed and unplanned fires, neither alone. Here, the importance to biodiversity conservation of all the components of the fire regime– interval, season, intensity and type (peat fire or otherwise) – and their domain of variability is emphasized. If conservation of biodiversity is to be guaranteed in a changing fire world, then much more knowledge about the systems being managed, gained in large part through effective monitoring, is needed. Issues such as targets and some assumptions of management are addressed here.

Fire and open ecosystems

2019 ◽  
pp. 97-120
Author(s):  
William J. Bond
Keyword(s):  
Vegetation Structure ◽  
Open Systems ◽  
Fire Regime ◽  
Alternative Stable States ◽  
Fire Regimes ◽  
Fire Effects ◽  
Emergent Property ◽  
Stable States ◽  
Mosaic Landscapes ◽  
Patterns And Processes

Can fire account for the widespread occurrence of open ecosystems? This chapter explores fire as a major consumer shaping vegetation in diverse regions worldwide. The concept of fire regime helps explain the diverse influences of fire on vegetation structure. Fire regimes select compatible growth forms from the species pool. These, in turn, create the fuel which in large part determines the fire regime. Experimental evidence can show whether fire is a major determinant of vegetation structure or merely an emergent property of ecosystems determined by climate and soils. Whether fires consume closed forests or stop at their margins will determine the dominant vegetation in mosaic landscapes. A mechanistic framework for analysing processes influencing fire effects on the boundary is introduced with examples. Pyrophilic open systems in mosaics with pyrophobic closed forests have been considered as examples of Alternative Stable States. Recent evidence for the patterns and processes expected by ASS theory are discussed.

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.

scholarly journals Fire regimes in eastern coastal fynbos: Imperatives and thresholds in managing for diversity

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Tineke Kraaij ◽  
Richard M. Cowling ◽  
Brian W. Van Wilgen
Keyword(s):  
Fire Ecology ◽  
Large Scale ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Season ◽  
Fire Intensity ◽  
Plant Management ◽  
Alien Plant ◽  
Invasive Alien Plant

Until recently, fire ecology was poorly understood in the eastern coastal region of the Cape Floral Kingdom (CFK), South Africa. Rainfall in the area is aseasonal and temperatures are milder than in the winter-rainfall and drier inland parts of the CFK, with implications for the management of fire regimes. We synthesised the findings of a research programme focused on informing ecologically sound management of fire in eastern coastal fynbos shrublands and explored potential east–west trends at the scales of study area and CFK in terms of fire return interval (FRI) and fire season. FRIs (8–26 years; 1980–2010) were comparable to those elsewhere in the CFK and appeared to be shorter in the eastern Tsitsikamma than in the western Outeniqua halves of the study area. Proteaceae juvenile periods (4–9 years) and post-fire recruitment success suggested that for biodiversity conservation purposes, FRIs should be ≥ 9 years in eastern coastal fynbos. Collectively, findings on the seasonality of actual fires and the seasonality of fire danger weather, lightning and post-fire proteoid recruitment suggested that fires in eastern coastal fynbos are not limited to any particular season. We articulated these findings into ecological thresholds pertaining to the different elements of the fire regime in eastern coastal fynbos, to guide adaptive management of fire in the Garden Route National Park and elsewhere in the region.Conservation implications: Wildfires are likely to remain dominant in eastern coastal fynbos, whilst large-scale implementation of prescribed burning is unattainable. Fires occurring in any season are not a reason for concern, although other constraints remain: the need for sufficient fire intensity, safety requirements, and integration of fire and invasive alien plant management.

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.

Relationships between prescribed burning and wildfire occurrence and intensity in pine - hardwood forests in north Mississippi, USA

2006 ◽  
Vol 15 (2) ◽  
pp. 203 ◽  
Author(s):  
Stephen Brewer ◽  
Corey Rogers
Keyword(s):  
Prescribed Burning ◽  
Fire Suppression ◽  
Late Summer ◽  
Fire Regimes ◽  
Hardwood Forests ◽  
Natural Fire ◽  
Wildfire Occurrence ◽  
Weather Patterns ◽  
Wildfire Hazard ◽  
Closed Canopy

Using Geographic Information Systems and US Forest Service data, we examined relationships between prescribed burning (from 1979 to 2000) and the incidence, size, and intensity of wildfires (from 1995 to 2000) in a landscape containing formerly fire-suppressed, closed-canopy hardwood and pine–hardwood forests. Results of hazard (failure) analyses did not show an increased likelihood of large, small, or intense wildfires with an increase in the number of years since the last prescribed fire. Wildfires of various sizes and intensities were more likely to occur in years with lower than average precipitation, regardless of when these areas were last burned. Calculations of expected lightning-fire potential based on weather patterns predicted a peak in lightning-started fires in the early to late summer. Lightning fires were rare, however, and wildfire activity was greatest in the spring and fall. We hypothesize that the ineffectiveness of prescribed burning in reducing wildfire hazard and the low incidence of wildfires in the midsummer in north Mississippi are both artifacts of fire suppression in the past, which converted open oak–pine woodlands with persistent pyrogenic surface fuels that accumulated over time to closed-canopy forests that lack such fuels. We suggest that open canopies and grass-based surface fuels must first be restored before prescribed burning will achieve most desirable management goals in this region, including hazard reduction and ecological restoration of natural fire regimes.

scholarly journals Quantifying pyrodiversity and its drivers

2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
Zachary L. Steel ◽  
Brandon M. Collins ◽  
David B. Sapsis ◽  
Scott L. Stephens
Keyword(s):  
United States ◽  
Human Population ◽  
Fire Regime ◽  
Important Determinant ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Western United States ◽  
Topographic Roughness ◽  
Spatio Temporal ◽  
Ecological Pattern

Pyrodiversity or variation in spatio-temporal fire patterns is increasingly recognized as an important determinant of ecological pattern and process, yet no consensus surrounds how best to quantify the phenomenon and its drivers remain largely untested. We present a generalizable functional diversity approach for measuring pyrodiversity, which incorporates multiple fire regime traits and can be applied across scales. Further, we tested the socioecological drivers of pyrodiversity among forests of the western United States. Largely mediated by burn activity, pyrodiversity was positively associated with actual evapotranspiration, climate water deficit, wilderness designation, elevation and topographic roughness but negatively with human population density. These results indicate pyrodiversity is highest in productive areas with pronounced annual dry periods and minimal fire suppression. This work can facilitate future pyrodiversity studies including whether and how it begets biodiversity among taxa, regions and fire regimes.

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