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

Haire, Sandra L.; McGarigal, Kevin; Miller, Carol

doi:10.1890/es12-00257.1

Cited by 30 publications

(18 citation statements)

References 70 publications

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“…Haire et al [67] analysed the distribution of fire sizes for the years 1984 to 2007 in the Western USA (Southwest, Sierra Nevada and Northern Rockies regions). In contrast to the aforementioned studies, no evidence was found of a decrease in the relative importance of large fires across the wilderness gradient, except in the Southwest.…”

Section: Wildfires As Fuel Treatmentsmentioning

confidence: 99%

Empirical Support for the Use of Prescribed Burning as a Fuel Treatment

Fernandes

2015

Curr Forestry Rep

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Prescribed burning as a fuel treatment seeks to moderate wildfire impacts and decreases the areal extent of wildfires by increasing the effectiveness of fire suppression. Assessment of prescribed burning effectiveness is frequently anecdotal or based on simulation. This paper examines recent observational evidence of prescribed fire effectiveness. The spread rate and intensity of experimental fires in distinct fuel types have been shown to increase with time since treatment (fuel age) following fuel structure recovery. Prescribed fire constrains the size and especially the severity of individual fires, even under extremely severe weather conditions. At larger spatial and temporal scales of analysis, the effect of fuel age on unplanned fire severity is also evident, whether it comes from wildfires entering treated areas or from wildfires in fuel-reduced areas resulting from earlier wildfire occurrences. The persistence of these effects is variable, depending on vegetation type and productivity. The long-term reduction in wildfire area brought about by prescribed fire can be difficult to ascertain. Substantial effort (annual treatment rates >5 % of the landscape) has been shown to effectively control the extent of wildfires in forests, with 3-4 units of prescribed burning needed to reduce wildfire by one unit. Future studies should consider the decrease in area burned by high-severity fire as a more meaningful and objective measure of prescribed fire effectiveness than the decrease in wildfire area and should strive to document fire behaviour in treated versus untreated areas during wildfires.

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Section: Wildfires As Fuel Treatmentsmentioning

confidence: 99%

Empirical Support for the Use of Prescribed Burning as a Fuel Treatment

Fernandes

2015

Curr Forestry Rep

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“…, Haire et al. ), and how quickly vegetation regenerates post‐fire (Peterson ). Shifting species compositions to alternative and persistent vegetation states following high‐severity or high‐frequency wildfires can change the effects of subsequent fires as documented in California, USA (van Wagtendonk et al.…”

Section: Introductionmentioning

confidence: 99%

“…Ecosystem state changes following repeated fires varies with burning conditions (Moritz et al 2011), vegetation type (Price et al 2012, Haire et al 2013, and how quickly vegetation regenerates post-fire (Peterson 2002). Shifting species compositions to alternative and persistent vegetation states following high-severity or high-frequency wildfires can change the effects of subsequent fires as documented in California, USA (van Wagtendonk et al 2012, Coppoletta et al, in press), the southwestern United States (Savage and Mast 2005), and Australia (Fletcher et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Repeated wildfires alter forest recovery of mixed‐conifer ecosystems

Stevens‐Rumann

Morgan

2016

Ecological Applications

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Most models project warmer and drier climates that will contribute to larger and more frequent wildfires. However, it remains unknown how repeated wildfires alter post-fire successional patterns and forest structure. Here, we test the hypothesis that the number of wildfires, as well as the order and severity of wildfire events interact to alter forest structure and vegetation recovery and implications for vegetation management. In 2014, we examined forest structure, composition, and tree regeneration in stands that burned 1-18 yr before a subsequent 2007 wildfire. Three important findings emerged: (1) Repeatedly burned forests had 15% less woody surface fuels and 31% lower tree seedling densities compared with forests that only experienced one recent wildfire. These repeatedly burned areas are recovering differently than sites burned once, which may lead to alternative ecosystem structure. (2) Order of burn severity (high followed by low severity compared with low followed by high severity) did influence forest characteristics. When low burn severity followed high, forests had 60% lower canopy closure and total basal area with 92% fewer tree seedlings than when high burn severity followed low. (3) Time between fires had no effect on most variables measured following the second fire except large woody fuels, canopy closure and tree seedling density. We conclude that repeatedly burned areas meet many vegetation management objectives of reduced fuel loads and moderate tree seedling densities. These differences in forest structure, composition, and tree regeneration have implications not only for the trajectories of these forests, but may reduce fire intensity and burn severity of subsequent wildfires and may be used in conjunction with future fire suppression tactics.

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“…A number of empirical studies have shown reduced wildfire spread and severity in recently burned areas (Teske et al 2012, Haire et al 2013, Prichard and Kennedy 2014, Parks et al 2015b, Holsinger et al 2016. Despite these and other studies of fire on fire feedbacks (reviewed in Prichard et al 2017), a mechanistic typology to disentangle underlying processes that generate both positive and negative feedbacks could help organize existing knowledge and the design of future studies.…”

Section: Discussionmentioning

confidence: 99%

Effects of accelerated wildfire on future fire regimes and implications for the United States federal fire policy

Ager¹,

Barros²,

Preisler³

et al. 2017

E&S

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. 2017. Effects of accelerated wildfire on future fire regimes and implications for the United States federal fire policy. Ecology and Society 22 (4) ABSTRACT. Wildland fire suppression practices in the western United States are being widely scrutinized by policymakers and scientists as costs escalate and large fires increasingly affect social and ecological values. One potential solution is to change current fire suppression tactics to intentionally increase the area burned under conditions when risks are acceptable to managers and fires can be used to achieve long-term restoration goals in fire adapted forests. We conducted experiments with the Envision landscape model to simulate increased levels of wildfire over a 50-year period on a 1.2 million ha landscape in the eastern Cascades of Oregon, USA. We hypothesized that at some level of burned area fuels would limit the growth of new fires, and fire effects on the composition and structure of forests would eventually reduce future fire intensity and severity. We found that doubling current rates of wildfire resulted in detectable feedbacks in area burned and fire intensity. Area burned in a given simulation year was reduced about 18% per unit area burned in the prior five years averaged across all scenarios. The reduction in area burned was accompanied by substantially lower fire severity, and vegetation shifted to open forest and grass-shrub conditions at the expense of old growth habitat. Negative fire feedbacks were slightly moderated by longer-term positive feedbacks, in which the effect of prior area burned diminished during the simulation. We discuss trade-offs between managing fuels with wildfire versus prescribed fire and mechanical fuel treatments from a social and policy standpoint. The study provides a useful modeling framework to consider the potential value of fire feedbacks as part of overall land management strategies to build fire resilient landscapes and reduce wildfire risk to communities in the western U.S. The results are also relevant to prior climate-wildfire studies that did not consider fire feedbacks in projections of future wildfire activity.

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

Cited by 30 publications

References 70 publications

Empirical Support for the Use of Prescribed Burning as a Fuel Treatment

Empirical Support for the Use of Prescribed Burning as a Fuel Treatment

Repeated wildfires alter forest recovery of mixed‐conifer ecosystems

Effects of accelerated wildfire on future fire regimes and implications for the United States federal fire policy

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