Article

Fire Probability, Fuel Treatment Effectiveness and Ecological Tradeoffs in Western U.S. Public Forests

October 2008
The Open Forest Science Journal 1(1)

DOI: 10.2174/1874398600801010001

Authors:

Fuel treatment effectiveness and non-treatment risks can be estimated from the probability of fire occurrence. Using extensive fire records for western US Forest Service lands, we estimate fuel treatments have a mean probability of 2.0-7.9% of encountering moderate-or high-severity fire during an assumed 20-year period of reduced fuels.

Beyond Fuel Treatment Effectiveness: Characterizing Interactions between Fire and Treatments in the US

Article

Full-text available

Oct 2016

In the United States, fuel reduction treatments are a standard land management tool to restore the structure and composition of forests that have been degraded by past management. Although treatments can have multiple purposes, their principal objective is to create landscape conditions where wildland fire can be safely managed to help achieve long-term land management goals. One critique is that fuel treatment benefits are unlikely to transpire due to the low probability that treated areas will be burned by a subsequent fire within a treatment's lifespan, but little quantitative information exists to corroborate this argument. We summarized the frequency, extent, and geographic variation of fire and fuel treatment interactions on federal lands within the conterminous United States (CONUS). We also assessed how the encounters between fuel treatments and fires varied with treatment size, treatment age, and number of times treated. Overall, 6.8% of treatment units evaluated were encountered by a subsequent fire during the study period, though this rate varied among ecoregions across the CONUS. Larger treatment units were more likely to be encountered by a fire, and treatment units were most frequently burned within one year of the most recent treatment, the latter of which is likely because of ongoing maintenance of existing treatments. Our results highlight the need to identify and prioritize additional opportunities to reduce fuel loading and fire risk on the millions of hectares of federal lands in the CONUS that are in need of restoration.

The High Costs and Low Benefits of Attempting to Increase Water Yield by Forest Removal in the Sierra Nevada

Technical Report

Full-text available

Jan 2016

Executive Summary Although there has been renewed interest in attempting to boost runoff from Sierra Nevada watersheds by removing copious amounts of forest cover, recent assessments promoting the approach have not given ample attention to well-known factors that sharply limit its utility for augmenting water supplies. These assessments have also largely ignored the considerable and enduring environmental costs of pursuing such an approach. This report provides a more thorough assessment of the environmental costs and limited utility for water supply from attempts to increase water yield via forest removal in the Sierra Nevada. Although data are limited from the Sierra Nevada, there is considerable body of information from applicable studies throughout the western U.S. that provides a context for assessing the limited benefits and significant costs of pursuing a forest removal or thinning management approach. This information indicates that the following limits the utility of any potential increase in water yield from forest removal:  Water yield increases are highly variable and not amenable to accurate prediction solely as a function of the amount of forest removed. However, aggregate data indicate that, on average, only very modest increases in water yield can be expected.  At the scale of major watersheds which supply water, any actual water yield increase from forest removal is likely to be too small to verify via field flow measurement.  Increases are very strongly affected by seasonal precipitation. Flow increases are most unlikely and smallest during dry years and during dry seasons. Thus, the approach has very nominal potential to improve water yield during droughts. For the same reasons, the approach is unlikely to provide additional water during dry seasons when demand is high relative to supply.  Increases are typically greatest during the period of highest runoff and during the wettest years. Due to this timing, any realized increases may have negligible benefits for water supply, while contributing to increased flooding.  Any increases in water yield from forest removal are diminished by transmission losses and storage losses, reducing any increase in downstream water supply.  Increased water yield in response to forest removal is transient. Any increases are erased by vegetative regrowth within several years after forest removal. In effect, forest removal promotes regrowth that exacerbates water demand by second-growth vegetation.  In the absence of continued removal, forest removal contributes to net reductions in low flows in subsequent decades, exacerbating water supply problems when demand is typically highest.  The maintenance of potential increases in water yield would require clearing of large percentage of forests at high frequency, on the order of 25% of watershed area every 10 years. This frequency and magnitude of forest removal would incur significant fiscal, logistical, and environmental costs. Due to these well-established limitations, previous assessments of this forest management approach, including those of the US Forest Service and National Academy of Sciences, have consistently noted that it is not likely to be practical due to the innate limitations identified above. The National Academy of Sciences consensus panel report on forest hydrology (2008) concluded: “…water yield increases from vegetation removal are often small and unsustainable, and timber harvest of areas sufficiently large to augment water yield can reduce water quality…There is little evidence that timber harvest can produce sustained increases in water yield over large areas…the potential for augmenting water yield on a sustainable basis in western forests and rangelands is very low.” Forest removal associated with attempts to increase water yield is unlikely to significantly alter fire behavior. There is a low probability that wildfire would affect treated areas, during the time when fuel levels are reduced, even with extensive forest removal. Weather, rather than the fuel conditions altered by fuels treatments, often exerts the dominant control on fire behavior, especially during large wildfires, further limiting the effectiveness of fuel treatments. Moreover, it is not ecologically desirable to reduce the extent and severity of wildfire in most Sierra Nevada forest, because there is currently a deficit of wildfire relative to historical levels. Wildfire is a natural keystone forest process which provides many critical medium- and long-term ecological functions and benefits for aquatic and terrestrial ecosystems. Intensive forest management aimed at elevating water yield would incur major and enduring environmental costs, due to the frequency and magnitude of forest removal that would be needed to maintain increases in water yield. Together with associated forest removal activities, including roads, landings, and skid trails, frequent and extensive forest removal would permanently degrade soils, riparian areas, aquatic systems, and water quality. The latter would incur significant water supply costs, including increased costs of treatment for elevated sediment and nutrient levels, as well as the likelihood of increased flood damage. Thus, the atbest modest benefits for water yield would come at the expense of high environmental and economic costs. Alternative forest and rangeland management measures can benefit water supplies by improving low flow and water quality conditions at a relatively low fiscal cost, while conveying a host of additional ecological benefits. These measures include sharply curtailing livestock grazing, reducing the extent and impacts of road networks, and re-establishment of beaver. These measures also likely increase the resiliency of watersheds in the face of drought, floods, and climate change.

Review of Fuel Treatment Effectiveness in Forests and Rangelands and a Case Study From the 2007 Megafires in Central Idaho USA

Article

Full-text available

Jan 2011

This report provides managers with the current state of knowledge regarding the effectiveness of fuel treatments for mitigating severe wildfire effects. A literature review examines the effectiveness of fuel treatments that had been previously applied and were subsequently burned through by wildfire in forests and rangelands. A case study focuses on WUI fuel treatments that were burned in the 2007 East Zone and Cascade megafires in central Idaho. Both the literature review and case study results support a manager consensus that forest thinning followed by some form of slash removal is most effective for reducing subsequent wildfire severity.

The Drivers of Effectiveness of Prescribed Fire Treatment

Article

Dec 2012
FOREST SCI

Owen F Price

Prescribed burning for fuel reduction is a major strategy for reducing the risk from unplanned fire. Although there are theoretical studies suggesting that prescribed fire has a strong negative influence on the subsequent area of unplanned fire (so-called leverage), many empirical studies find a more modest influence. Here, I develop a series of simulations to explore the landscape drivers of leverage. Leverage declines with treatment level in a nonlinear, "decay" relationship, implying diminishing effectiveness. The spatial configuration of the prescribed fire treatment has a major effect: long linear (gridded) barriers are far more effective than patch barriers, but gaps in the grid lead to large reductions in leverage. However, the extent of unplanned fires in the landscape has the largest influence such that a landscape with 3% annual extent has only one-fifth of the leverage of a landscape with 28%. Leverage decreases with the probability of spread, suggesting that treatment is less effective when fire weather is severe. For gridded designs, leverage increases with the size of individual fires, but this is not the case for patch designs. These results agree well with recent empirical studies finding that prescribed burning has only a modest effect on subsequent unplanned fire in many biomes. They also help to explain why those empirical studies report lower effectiveness than many simulation studies. In practice, leverage values >1 (replacement of unplanned with planned fire) are hard to achieve.

Effects of Fire and Commercial Thinning on Future Habitat of the Northern Spotted Owl

Article

Full-text available

Jul 2014
Open Orthop J

The Northern Spotted Owl (Strix occidentalis caurina) is an emblematic, threatened raptor associated with dense, late-successional forests in the Pacific Northwest, USA. Concerns over high-severity fire and reduced timber harvesting have led to programs to commercially thin forests, and this may occur within habitat designated as "critical" for spotted owls. However, thinning is only allowed under the U.S. Government spotted owl guidelines if the long-term benefits clearly outweigh adverse impacts. This possibility remains uncertain. Adverse impacts from commercial thinning may be caused by removal of key habitat elements and creation of forests that are more open than those likely to be occupied by spotted owls. Benefits of thinning may accrue through reduction in high-severity fire, yet whether the firereduction benefits accrue faster than the adverse impacts of reduced late-successional habitat from thinning remains an untested hypothesis. We found that rotations of severe fire (the time required for high-severity fire to burn an area equal to the area of interest once) in spotted owl habitat since 1996, the earliest date we could use, were 362 and 913 years for the two regions of interest: the Klamath and dry Cascades. Using empirical data, we calculated the future amount of spotted owl habitat that may be maintained with these rates of high-severity fire and ongoing forest regrowth rates with and without commercial thinning. Over 40 years, habitat loss would be far greater than with no thinning because, under a "best case" scenario, thinning reduced 3.4 and 6.0 times more dense, late-successional forest than it prevented from burning in high-severity fire in the Klamath and dry Cascades, respectively. Even if rates of fire increase substantially, the requirement that the long-term benefits of commercial thinning clearly outweigh adverse impacts is not attainable with commercial thinning in spotted owl habitat. It is also becoming increasingly recognized that exclusion of high-severity fire may not benefit spotted owls in areas where owls evolved with reoccurring fires in the landscape.

Can fuel-reduction treatments really increase forest carbon storage in the western US by reducing future fire emissions?

Article

Mar 2012
FRONT ECOL ENVIRON

It has been suggested that thinning trees and other fuel-reduction practices aimed at reducing the probability of high-severity forest fire are consistent with efforts to keep carbon (C) sequestered in terrestrial pools, and that such practices should therefore be rewarded rather than penalized in C-accounting schemes. By evaluating how fuel treatments, wildfire, and their interactions affect forest C stocks across a wide range of spatial and temporal scales, we conclude that this is extremely unlikely. Our review reveals high C losses associated with fuel treatment, only modest differences in the combustive losses associated with high-severity fire and the low-severity fire that fuel treatment is meant to encourage, and a low likelihood that treated forests will be exposed to fire. Although fuel-reduction treatments may be necessary to restore historical functionality to firesuppressed ecosystems, we found little credible evidence that such efforts have the added benefit of increasing terrestrial C stocks.

Can fuel-reduction treatments really increase forest carbon storage in the western US by reducing future fire emissions?

Article

Full-text available

Mar 2012

It has been suggested that thinning trees and other fuel-reduction practices aimed at reducing the probability of high-severity forest fire are consistent with efforts to keep carbon (C) sequestered in terrestrial pools, and that such practices should therefore be rewarded rather than penalized in C-accounting schemes. By evaluating how fuel treatments, wildfire, and their interactions affect forest stocks across a wide range of spatial and temporal scales, we conclude that this is extremely unlikely. Our review reveals high losses associated with fuel treatment, only modest differences in the combustive losses associated with high-severity fire and the low-severity fire that fuel treatment is meant to encourage, and a low likelihood that treated forests will be exposed to fire. Although fuel-reduction treatments may be necessary to restore historical functionality to firesuppressed ecosystems, we found little credible evidence that such efforts have the added benefit of increasing terrestrial stocks.

Prescribed fire effects on field-derived and simulated forest carbon stocks over time

Article

Dec 2013
FOREST ECOL MANAG

Creating Strategic Reserves to Protect Forest Carbon and Reduce Biodiversity Losses in the United States

Article

Full-text available

May 2022

This paper provides a review and comparison of strategies to increase forest carbon, and reduce species losses for climate change mitigation and adaptation in the United States. It compares forest management strategies and actions that are taking place or being proposed to reduce wildfire risk and to increase carbon storage with recent research findings. International agreements state that safeguarding biodiversity and ecosystems is fundamental to climate resilience with respect to climate change impacts on them, and their roles in adaptation and mitigation. The recent Intergovernmental Panel on Climate Change report on impacts, mitigation, and adaptation found, and member countries agreed, that maintaining the resilience of biodiversity and ecosystem services at a global scale is “fundamental” for climate mitigation and adaptation, and requires “effective and equitable conservation of approximately 30 to 50% of Earth’s land, freshwater and ocean areas, including current near-natural ecosystems.” Our key message is that many of the current and proposed forest management actions in the United States are not consistent with climate goals, and that preserving 30 to 50% of lands for their carbon, biodiversity and water is feasible, effective, and necessary for achieving them.

The Costs and Costs Avoided From Wildfire Fire Management—A Conceptual Framework for a Value of Information Analysis

Article

Full-text available

May 2022

Wildfire is an integral part of many ecosystems, and wildland fires also have the potential for costly impacts to human health and safety, and damage to structures and natural resources. Public land managers use various strategies for managing landscape conditions that can affect wildfire, broadly: fuel treatment (and other pre-fire risk mitigation), fire suppression, and post-fire landscape rehabilitation. However, with any of these strategies there is considerable uncertainty in the outcomes that managers can obtain, and thus on the societal costs and benefits associated with wildland fire management. Managers address that uncertainty by using available information to inform their strategy choices. The value of information (VOI) to the land manager is defined as the expected gains from improved wildland fire management outcomes that result from using the information. This paper discusses estimating the value of information using two approaches: a microeconomic theoretical approach, and the Bayesian decision-tree approach frequently used in the VOI literature. These approaches could be used for valuing specific pieces of information (with absolute values), and for prioritizing (with relative values) which areas to focus on for future research.

Strategic Forest Reserves can protect biodiversity in the western United States and mitigate climate change

Article

Full-text available

Dec 2021

Forest preservation is crucial for protecting biodiversity and mitigating climate change. Here we assess current forest preservation in the western United States using spatial data and find that beyond the 18.9% (17.5 Mha) currently protected, an additional 11.1% (10.3 Mha) is needed to achieve 30% preservation by 2030 (30 × 30). To help meet this regional preservation target, we developed a framework that prioritizes forestlands for preservation using spatial metrics of biodiversity and/or carbon within each ecoregion. We show that meeting this preservation target would lead to greater protection of animal and tree species habitat, current carbon stocks, future carbon accumulation, and forests that are important for surface drinking water. The highest priority forestlands are primarily owned by the federal government, though substantial areas are also owned by private entities and state and tribal governments. Establishing Strategic Forest Reserves would help protect biodiversity and carbon for climate adaptation and mitigation.

Adapting western North American forests to climate change and wildfires: 10 common questions

Article

Full-text available

Aug 2021

We review science‐based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes. As part of the review, we address common questions associated with climate adaptation and realignment treatments that run counter to a broad consensus in the literature. These include: (1) Are the effects of fire exclusion overstated? If so, are treatments unwarranted and even counterproductive? (2) Is forest thinning alone sufficient to mitigate wildfire hazard? (3) Can forest thinning and prescribed burning solve the problem? (4) Should active forest management, including forest thinning, be concentrated in the wildland urban interface (WUI)? (5) Can wildfires on their own do the work of fuel treatments? (6) Is the primary objective of fuel reduction treatments to assist in future firefighting response and containment? (7) Do fuel treatments work under extreme fire weather? (8) Is the scale of the problem too great – can we ever catch up? (9) Will planting more trees mitigate climate change in wNA forests? and (10) Is post‐fire management needed or even ecologically justified? Based on our review of the scientific evidence, a range of proactive management actions are justified and necessary to keep pace with changing climatic and wildfire regimes and declining forest successional heterogeneity after severe wildfires. Science‐based adaptation options include the use of managed wildfire, prescribed burning, and coupled mechanical thinning and prescribed burning as is consistent with land management allocations and forest conditions. Although some current models of fire management in wNA are averse to short‐term risks and uncertainties, the long‐term environmental, social, and cultural consequences of wildfire management primarily grounded in fire suppression are well documented, highlighting an urgency to invest in intentional forest management and restoration of active fire regimes.

We refute the “conundrum of agenda-driven science” with documentation: A comment on Peery et al. 2019

Article

Full-text available

Jul 2019

In Peery et al.’s letter (2019) in Frontiers in Ecology and the Environment, we were accused of “agenda-driven” science with regard to our research pertaining to spotted owls and wildland fire (e.g., Hanson et al. 2018, Lee 2018). Peery et al. (2019) criticize us for stating our view that the current scientific evidence warrants increased protection of forests, while they advocate for their own agenda promoting commercial logging on federal lands in spotted owl habitat (Jones et al. 2016; Peery et al. 2019). We receive funding from conservation-oriented foundations which aligns with our motivations, while Perry et al. receive funding from agencies that are supportive of forestry and logging, which clearly influences their interpretations. Scientists’ points of view certainly influence their interpretations of the data as well as the types of experiments that we all conduct. This isn’t a problem as long as our disagreements and differences in interpretation are worked out in the normal scientific process of peer-reviewed publications and factually based commentary about each other’s work. Peery et al. attempted to win this debate by attacking us with false, biased, and undocumented claims, against the ethical code of the Ecological Society of America. Sadly, the journal that published the defamatory letter by Peery et al. has refused to print any rebuttal by us to correct the record. Here, we refute each of Peery et al.’s claims and include supporting documentation.

Tamm review: The effects of prescribed fire on wildfire regimes and impacts: A framework for comparison

Article

Nov 2020
FOREST ECOL MANAG

Prescribed fire can result in significant benefits to ecosystems and society. Examples include improved wildlife habitat, enhanced biodiversity, reduced threat of destructive wildfire, and enhanced ecosystem resilience. Prescribed fire can also come with costs, such as reduced air quality and impacts to fire sensitive species. To plan for appropriate use of prescribed fire, managers need information on the tradeoffs between prescribed fire and wildfire regimes. In this study, we argue that information on tradeoffs should be presented at spatial and temporal scales commensurate with the scales at which these processes occur and that simulation modeling exercises should include some realistic measure of wildfire probability. To that end, we synthesized available scientific literature on relationships between prescribed fire and wildfire regimes, and their associated ecological and societal effects, focusing specifically on simulation modeling studies that consider wildfire probability and empirical and modeling studies that consider prescribed fire and wildfire regimes at spatial and temporal scales beyond individual events. Both empirical and modeling studies overwhelmingly show that increasing use of prescribed fire can result in wildfire regimes of lower extent and intensity. In some studies, a consequence associated with increased use of prescribed fire is an increase in the total, cumulative amount of fire on a landscape over time. Presumably this has implications for emissions and ecosystem carbon, however, effects on ecosystem carbon dynamics are much less clear as results vary considerably across studies. Results likely vary because studies use various landscape models with different parameter settings for processes (e.g., vegetation succession) and use different methodologies, time frames, and fire management and climate change scenarios. Future syntheses and meta-analyses would benefit from researchers providing more comprehensive and transparent documentation of model parameters, assumptions, and limitations. The literature review also revealed that studies on the implications of prescribed fire and wildfire regimes with regard to values other than carbon and emissions are scant and this represents a critical research need. Empirical studies are needed to calibrate and provide magnitude of order comparisons with simulation models and address tradeoffs with respect to other values (e.g., wildland urban interface, wildlife habitat). Such studies should be conducted with consideration for our framework, which includes the implications of prescribed fire and wildfire across broad spatial and temporal scales.

Building Carbon in America's Farms, Forests, and Grasslands: Foundations for a Policy Roadmap

Technical Report

Full-text available

Feb 2016

The vegetation and soils found in landscapes across the United States serve as carbon sinks, removing an estimated 850 million metric tons of CO2e from the atmosphere each year and offsetting 16 percent of annual industrial emissions. There is significant uncertainty about the future and scale of this sink. Failure to stabilize the current sink and preserve U.S. land carbon mitigation capacity could jeopardize the effectiveness of U.S. climate change policy and the nation’s ability to meet future emissions reduction targets. To address this challenge, a consortium of organizations and experts came together to launch the Land Carbon Policy Roadmap (LCPR) initiative to develop and implement policy recommendations that ensure U.S. lands continue to significantly reduce economy-wide emissions through 2050 and to provide robust agricultural, silvicultural, and ecosystem services. This report is the first step toward developing that roadmap.

Critical wind speeds suggest wind could be an important disturbance agent in Amazonian forests

Article

Full-text available

May 2019

Recent research in the central Amazon suggests that wind is a major agent of disturbance, however, a mechanistic understanding of how wind may lead to tree mortality in Amazonian forests remains unclear. Here we estimated wind speeds necessary to topple central Amazon trees by linking both static and dynamic versions of two wind speed estimation methods (four methods total) to field data on tree failure derived from a static winching study. Static versions of these methods assumed invariant wind characteristics as more trees failed, while dynamic versions updated tree spacing, leaf area index and wind profiles progressively after each tree failure. First, we used a profile method which estimates wind force on individual trees by segments. We calculated drag on each segment and converted drag into basal turning moment, and compared the summed turning moments to the critical turning moment measured in the winching study. Estimated critical wind speeds from the static profile method varied greatly, from 10.75 m s−1 to >120.0 m s−1 with a mean of 45.70 m s−1. Critical wind speeds estimated with static approaches decreased with tree size but were not significantly different between two focal genera. Primary drivers of variation in critical wind speed were tree height and crown size. Second, we used the turning moment coefficient method of Hale, S.E., Gardiner, B., Peace, A., Nicoll, B., Taylor, P. and Pizzirani, S. 2015 Comparison and validation of three versions of a forest wind risk model. Environ. Model. Softw.68, 27–41. doi:10.1016/j.envsoft.2015.01.016.; the static version of this method yielded less-variable estimates, ranging from 18.98 to 52.01 m s−1, with a mean of 30.88 m s−1. Notably, the two static methods for estimating critical wind speeds differed in the trees they identified as having the highest and lowest critical wind speeds. Dynamic variants of the above two methods produced greatly reduced ranges in CWS estimates for our study trees, because after the early tree failures, remaining trees were subject to greater wind penetration into the stand and thus greater loading for a given above-canopy wind speed. CWS estimated with dynamic approaches differed significantly between the focal taxa. Nevertheless, both estimates suggest that wind speeds commonly observed during Amazon storms are sufficient to produce widespread tree damage and mortality.

Prioritising fuels reduction for water supply protection

Article

Apr 2019
INT J WILDLAND FIRE

Concerns over wildfire impacts to water supplies have motivated efforts to mitigate risk by reducing forest fuels. Methods to assess fuel treatment effects and prioritise their placement are needed to guide risk mitigation efforts. We present a fuel treatment optimisation model to minimise risk to multiple water supplies based on constraints for treatment feasibility and cost. Risk is quantified as the expected sediment impact costs to water supplies by combining measures of fire likelihood and behaviour, erosion, sediment transport and water supply vulnerability. We demonstrate the model's utility for prioritising fuel treatments in two large watersheds in Colorado, USA, that are critical for municipal water supply. Our results indicate that wildfire risk to water supplies can be substantially reduced by treating a small portion of the watersheds that have dense, fire-prone forests on steep slopes that drain to water supply infrastructure. Our results also show that the cost of fuel treatments outweighs the expected cost savings from reduced sediment inputs owing to the low probability of fuel treatments encountering wildfire and the high cost of thinning forests. This highlights the need to expand use of more cost-effective treatments, like prescribed fire, and to identify fuel treatment projects that benefit multiple resources.

Evaluating Sensitivity of the Ranking of Forest Fuel Treatments to Manager’s Risk Attitudes and the Importance of Treatment Objectives, Montana, USA

Article

Full-text available

Feb 2019

This study develops a conceptual framework for evaluating the sensitivity of the ranking of forest fuel treatment strategies (FTSs) to variation in managers’ risk attitudes and the importance ratings managers assign to fuel treatment objectives and demonstrates the application of the framework using a case study. The conceptual framework involves (1) defining a utility function on an index that is a weighted average of fuel treatment objectives and incorporates a manager’s risk attitude; (2) using the utility function to calculate utility values for FTSs; (3) applying the stochastic efficiency with respect to a function method to utility values to obtain certainty equivalents (CEs); and (4) ranking FTSs based on statistically significant differences in median CEs for pairs of FTSs. The case study involves three (federal, state, and private) forested areas in Flathead County, Montana, USA, three FTSs (i.e., Community Wildfire Protection Plan (CWPP) Priority; CWPP & Wildland-Urban Interface Priority; and No Priority), three treatment objectives (i.e., minimizing expected residential monetary losses from wildfire, minimizing expected deviation of forest ecological conditions from their historic range and variability, and maximizing expected net returns from timber harvesting associated with fuel treatment), two risk attitudes (i.e., almost risk neutral and highly risk averse), and 35 weight scenarios for treatment objectives. Case study results are used to test the hypothesis that the ranking of FTSs is sensitive to manager’s risk attitudes and the importance ratings for management objectives. The ranking of FTSs for the three forested areas was insensitive for an almost risk neutral manager and sensitive for a highly risk averse manager. In general, the case study indicates that the ranking of FTSs is sensitive to both a forest manager’s risk attitudes and the importance ratings assigned to fuel treatment objectives.

Assessing the Effects of Climate Change and Fuel Treatments on Forest Dynamics and Wildfire in Dry Mixed-Conifer Forests of the Inland West: Linking Landscape and Social Perspectives

Thesis

Full-text available

Mar 2018

Brooke A. Cassell

Over the past century in the western United States, warming has produced larger and more severe wildfires than previously recorded. General circulation models and their ensembles project continued increases in temperature and the proportion of precipitation falling as rain. Warmer conditions may change forest successional trajectories by modifying rates of vegetation establishment, competition, growth, reproduction, and mortality. Many questions remain regarding how these changes will occur across landscapes and how disturbances, such as wildfire, may interact with changes to climate and vegetation. Forest management is used to proactively modify forest structure and composition to improve fire resilience. Yet, research is needed to assess how to best utilize mechanical fuel reduction and prescribed fire at the landscape scale. Human communities also exist within these landscapes, and decisions regarding how to manage forests must carefully consider how management will affect such communities. In this work, I analyzed three aspects of forest management at large spatiotemporal scales: (1) climate effects on forest composition and wildfire activity; (2) efficacy of fuel management strategies toward reducing wildfire spread and severity; and, (3) local resident perspectives on forest management. Using a forest landscape model, simulations of forest dynamics were used to investigate relationships among climate, wildfire, and topography with long-term changes in biomass for a fire-prone dry-conifer landscape in eastern Oregon, United States. I compared the effectiveness of fuel treatment strategies for reducing wildfire under both contemporary and extreme weather. Fuel treatment scenarios included “business as usual” and strategies that increased the area treated with harvest and prescribed fire, and all strategies were compared by distributing them across the landscape and by concentrating them in areas at the greatest risk for high-severity wildfire. To investigate local community preferences for forest management, I used focus groups, interviews, and questionnaires. Through open-ended questions and a public participation geographic information systems (PPGIS) mapping exercise, local residents expressed their views on fuels reduction treatments by commercial and non-commercial harvest and prescribed fire. Emergent themes were used to inform alternative management scenarios to explore the usefulness of using PPGIS to generate modeling inputs. Scenarios ranged from restoration-only treatments to short-rotation commercial harvest. Under climate change, wildfire was more frequent, more expansive, and more severe, and ponderosa pine expanded its range into existing shrublands and high-elevation zones. There was a near-complete loss of native high-elevation tree species, such as Engelmann spruce and whitebark pine. Loss of these species were most strongly linked to burn frequency; this effect was greatest at high elevations and on steep slopes. Fuel reduction was effective at reducing wildfire spread and severity compared to unmanaged landscapes. Spatially optimizing mechanical removal of trees in areas at risk for high-severity wildfire was equally effective as distributing tree removal across the landscape. Tripling the annual area of prescribed burns was needed to affect landscape-level wildfire spread and severity, and distributing prescribed burns across the study area was more effective than concentrating fires in high-risk areas. Focus group participants generally approved of all types of forest management and agreed that all areas should be managed with the “appropriate” type of treatment for each forest stand, and that decisions about management should be made by “experts.” However, there was disagreement related to who the “experts” are and how much public input should be included in the decision making process. Degree of trust in land management agencies contributed to polarized views about who the primary decision makers and what the focus of management should be. While most participants agreed that prescribed fire was a useful tool for preventing wildfire spread and severity, many expressed reservations about its use. I conclude that forest management can be used to reduce wildfire activity in dry-mixed conifer forests and that spatially optimizing mechanical treatments in high-risk areas can be a useful tool for reducing the cost and ecological impact associated with harvest operations. While reducing the severity and spread of wildfire may slow some long-term species shifts, high sub-alpine tree mortality occurred under all climate and fuel treatment scenarios. Thus, while forest management may prolong the existence of sub-alpine forests, shifts in temperature, precipitation, and wildfire may overtake management within this century. The use of PPGIS was useful for delineating the range of forest management preferences within the local community, for identifying areas of agreement among residents who have otherwise polarized views, and for generating modeling inputs that reflect views that may not be obtained through extant official channels for public participation. Because the local community has concerns about the use of prescribed fire, more education and outreach is needed. This may increase public acceptance of the amounts of prescribed fire needed to modify wildfire trajectories under future climate conditions.

Forward-looking farmers owning multiple potential wetland restoration sites: implications for efficient restoration

Article

Full-text available

Apr 2018
ENVIRON MANAGE

Wetland restoration can increase the provision of multiple non-market ecosystem services. Environmental and socio-economic factors need to be accounted for when land is withdrawn from agriculture and wetlands are restored. We build multi-objective optimization models to provide decision support for wetland restoration in the Le Sueur river watershed in Southern Minnesota. We integrate environmental objectives of sediment reduction and habitat protection with socio-economic factors associated with the overlap of private land with potential wetland restoration sites in the watershed and the costs representing forward-looking farmers voluntarily taking land out of agricultural production in favor of wetland restoration. Our results demonstrate that the inclusion of these factors early on in the restoration planning process affects both the total costs of the restoration project and the spatial distribution of optimally selected wetland restoration sites.

The impact of land ownership, firefighting, and reserve status on fire probability in California

Article

Full-text available

Mar 2018
ENVIRON RES LETT

The extent of wildfires in the western United States is increasing, but how land ownership, firefighting, and reserve status influence fire probability is unclear. California serves as a unique natural experiment to estimate the impact of these factors, as ownership is split equally between federal and non-federal landowners; there is a relatively large proportion of reserved lands where extractive uses are prohibited and fire suppression is limited; and land ownership and firefighting responsibility are purposefully not always aligned. Panel Poisson regression techniques and pre-regression matching were used to model changes in annual fire probability from 1950–2015 on reserve and non-reserve lands on federal and non-federal ownerships across four vegetation types: forests, rangelands, shrublands, and forests without commercial species. Fire probability was found to have increased over time across all 32 categories. A marginal effects analysis showed that federal ownership and firefighting was associated with increased fire probability, and that the difference in fire probability on federal versus non-federal lands is increasing over time. Ownership, firefighting, and reserve status, played roughly equal roles in determining fire probability, and were found to have much greater influence than average maximum temperature (°C) during summer months (June, July, August), average annual precipitation (cm), and average annual topsoil moisture content by volume, demonstrating the critical role these factors play in western fire regimes and the importance of including them in future analysis focused on understanding and predicting wildfire in the Western United States.

Modeling Fuel Treatment Leverage: Encounter Rates, Risk Reduction, and Suppression Cost Impacts

Article

Full-text available

Nov 2017

The primary theme of this study is the cost-effectiveness of fuel treatments at multiple scales of investment. We focused on the nexus of fuel management and suppression response planning, designing spatial fuel treatment strategies to incorporate landscape features that provide control opportunities that are relevant to fire operations. Our analysis explored the frequency and magnitude of fire-treatment encounters, which are critical determinants of treatment efficacy. Additionally, we examined avoided area burned, avoided suppression costs, and avoided damages, and combined all three under the umbrella of leverage to explore multiple dimensions with which to characterize return on investment. We chose the Sierra National Forest, California, USA, as our study site, due to previous work providing relevant data and analytical products, and because it has the potential for large, long-duration fires and corresponding potential for high suppression expenditures. Modeling results generally confirmed that fire-treatment encounters are rare, such that median suppression cost savings are zero, but in extreme years, savings can more than offset upfront investments. Further, reductions in risk can expand areas where moderated suppression response would be appropriate, and these areas can be mapped in relation to fire control opportunities.

Multiobjective Prioritization of Preselected Fuel Treatment Strategies for Public Forestland: A Case Study in Flathead County, Montana

Article

Full-text available

Aug 2017
FOREST SCI

Preferred fuel treatment strategies (FTSs) were determined for two public forests in Flathead County, Montana, for the period 2010–59 using a multiple-objective evaluation method that accounts for future residential development in the WUI and climate change. Three fuel management objectives were used to evaluate and rank FTSs: minimizing monetary residential losses due to wildfire, minimizing deviation from historical forest ecological conditions, and maximizing net revenue from timber harvesting associated with fuel treatment. Preferred FTSs varied across planning periods for both forests. For the Flathead National Forest, managed by the US Forest Service, there was a unique preferred FTS for each subperiod. For the forest managed by the Montana Department of Natural Resources and Conservation, two spatially prioritized FTSs were equally preferred in period 1, one spatially prioritized FTS was preferred in subperiod 2, no spatially prioritized FTS was preferred in periods 3 and 4, and the three FTSs were equally preferred in period 5. Results suggest that evaluating FTSs for a forest on the basis of a single management objective could give misleading results about the most preferred FTS and that targeting fuel treatments based on spatial priorities may not be superior to random allocation of fuel treatments to eligible stands.

Long-term effects of fuel treatments on aboveground biomass accumulation in ponderosa pine forests of the northern Rocky Mountains

Article

Jun 2017
FOREST ECOL MANAG

Fuel treatments in ponderosa pine forests of the northern Rocky Mountains are commonly used to modify fire behavior, but it is unclear how different fuel treatments impact the subsequent production and distribution of aboveground biomass, especially in the long term. This research evaluated aboveground biomass responses 23 years after treatment in two silvicultural installations with different cutting and underburning prescriptions in western Montana. The thinning installation included control (no treatment), thin/no burn, thin/spring burn, and thin/fall burn treatments. The shelterwood installation included control, cut/no burn, cut/wet burn, and cut/dry burn treatments. Across all fuel treatments in both the thinning and shelterwood installations, tree biomass had recovered to pre-harvest levels by 2015, or 23 years post-treatment. In the thinning, total aboveground and live-tree biomass were greatest in the control, but did not differ among the three thinned fuel treatments. Forest floor biomass was lower in the two burned treatments relative to the two unburned treatments. Seedling, vegetation, stump, and snag biomass did not differ among the four treatments. In the shelterwood, total aboveground and live tree biomass were both greater in the unburned treatments relative to the burned treatments. Forest floor and snag biomass also tended to be lower in the burned treatments. Seedling, vegetation, and stump biomass were similar across all treatments. This research shows that tree biomass in ponderosa pine stands subjected to common fuels treatments can recover to pre-harvest levels in less than 23 years, while still exhibiting reduced stand densities that promote forest restoration objectives. Burgeoning biomass at the seedling layer suggests that additional understory treatments are necessary in order to abate ladder fuel development and sustain resistance to high-severity wildfire.

Numerical Investigation of Aggregated Fuel Spatial Pattern Impacts on Fire Behavior

Article

Full-text available

Jun 2017

Landscape heterogeneity shapes species distributions, interactions, and fluctuations. Historically, in dry forest ecosystems, low canopy cover and heterogeneous fuel patterns often moderated disturbances like fire. Over the last century, however, increases in canopy cover and more homogeneous patterns have contributed to altered fire regimes with higher fire severity. Fire management strategies emphasize increasing within-stand heterogeneity with aggregated fuel patterns to alter potential fire behavior. Yet, little is known about how such patterns may affect fire behavior, or how sensitive fire behavior changes from fuel patterns are to winds and canopy cover. Here, we used a physics-based fire behavior model, FIRETEC, to explore the impacts of spatially aggregated fuel patterns on the mean and variability of stand-level fire behavior, and to test sensitivity of these effects to wind and canopy cover. Qualitative and quantitative approaches suggest that spatial fuel patterns can significantly affect fire behavior. Based on our results we propose three hypotheses: (1) aggregated spatial fuel patterns primarily affect fire behavior by increasing variability; (2) this variability should increase with spatial scale of aggregation; and (3) fire behavior sensitivity to spatial pattern effects should be more pronounced under moderate wind and fuel conditions.

Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA

Article

Full-text available

Jan 2017
ECOL SOC

Jennifer Koch

Return on investment from fuel treatments to reduce severe wildfire and erosion in a watershed investment program in Colorado

Article

Aug 2017

A small but growing number of watershed investment programs in the western United States focus on wildfire risk reduction to municipal water supplies. This paper used return on investment (ROI) analysis to quantify how the amounts and placement of fuel treatment interventions would reduce sediment loading to the Strontia Springs Reservoir in the Upper South Platte River watershed southwest of Denver, Colorado following an extreme fire event. We simulated various extents of fuel mitigation activities under two placement strategies: (a) a strategic treatment prioritization map and (b) accessibility. Potential fire behavior was modeled under each extent and scenario to determine the impact on fire severity, and this was used to estimate expected change in post-fire erosion due to treatments. We found a positive ROI after large storm events when fire mitigation treatments were placed in priority areas with diminishing marginal returns after treating >50e80% of the forested area. While our ROI results should not be used prescriptively they do show that, conditional on severe fire occurrence and precipitation, investments in the Upper South Platte could feasibly lead to positive financial returns based on the reduced costs of dredging sediment from the reservoir. While our analysis showed positive ROI focusing only on post-fire erosion mitigation, it is important to consider multiple benefits in future ROI calculations and increase monitoring and evaluation of these benefits of wildfire fuel reduction investments for different site conditions and climates.

Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA

Article

Full-text available

Mar 2017
ECOL SOC

Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landscape in the eastern Cascades of Oregon. Our model incorporated existing models of vegetation succession and fire spread and information from original empirical studies of landowner decision making. Our findings indicate that alternative management strategies can have variable effects on landscape outcomes over 50 years for fire, socioeconomic, and ecosystem services metrics. For example, scenarios with federal restoration treatments had slightly less high-severity fire than a scenario without treatment; exposure of homes in the wildland-urban interface to fire was also slightly less with restoration treatments compared to no management. Treatments appeared to be more effective at reducing high-severity fire in years with more fire than in years with less fire. Under the current management scenario, timber production could be maintained for at least 50 years on federal lands. Under an accelerated restoration scenario, timber production fell because of a shortage of areas meeting current stand structure treatment targets. Trade-offs between restoration outcomes (e.g., open forests with large fire-resistant trees) and habitat for species that require dense older forests were evident. For example, the proportional area of nesting habitat for northern spotted owl (Strix occidentalis) was somewhat less after 50 years under the restoration scenarios than under no management. However, the amount of resilient older forest structure and habitat for white-headed woodpecker (Leuconotopicus albolarvatus) was higher after 50 years under active management. More carbon was stored on this landscape without management than with management, despite the occurrence of high-severity wildfire. Our results and further applications of the model could be used in collaborative settings to facilitate discussion and development of policies and practices for fire-prone landscapes.

Restoring and managing low-severity fire in dry-forest landscapes of the western USA

Article

Full-text available

Feb 2017
PLOS ONE

William L. Baker

Low-severity fires that killed few canopy trees played a significant historical role in dry forests of the western USA and warrant restoration and management, but historical rates of burning remain uncertain. Past reconstructions focused on on dating fire years, not measuring historical rates of burning. Past statistics, including mean composite fire interval (mean CFI) and individual-tree fire interval (mean ITFI) have biases and inaccuracies if used as estimators of rates. In this study, I used regression, with a calibration dataset of 96 cases, to test whether these statistics could accurately predict two equivalent historical rates, population mean fire interval (PMFI) and fire rotation (FR). The best model, using Weibull mean ITFI, had low prediction error and R²adj = 0.972. I used this model to predict historical PMFI/FR at 252 sites spanning dry forests. Historical PMFI/FR for a pool of 342 calibration and predicted sites had a mean of 39 years and median of 30 years. Short (< 25 years) mean PMFI/FRs were in Arizona and New Mexico and scattered in other states. Long (> 55 years) mean PMFI/FRs were mainly from northern New Mexico to South Dakota. Mountain sites often had a large range in PMFI/FR. Nearly all 342 estimates are for old forests with a history of primarily low-severity fire, found across only about 34% of historical dry-forest area. Frequent fire (PMFI/FR < 25 years) was found across only about 14% of historical dry-forest area, with 86% having multidecadal rates of low-severity fire. Historical fuels (e.g., understory shrubs and small trees) could fully recover between multidecadal fires, allowing some denser forests and some ecosystem processes and wildlife habitat to be less limited by fire. Lower historical rates mean less restoration treatment is needed before beginning managed fire for resource benefits, where feasible. Mimicking patterns of variability in historical low-severity fire regimes would likely benefit biological diversity and ecosystem functioning.

Does increased forest protection correspond to higher fire severity in frequent-fire forests of the western United States?

Article

Full-text available

Oct 2016

There is a widespread view among land managers and others that the protected status of many forestlands in the western United States corresponds with higher fire severity levels due to historical restrictions on logging that contribute to greater amounts of biomass and fuel loading in less intensively managed areas, particularly after decades of fire suppression. This view has led to recent proposals-both administrative and legislative-to reduce or eliminate forest protections and increase some forms of logging based on the belief that restrictions on active management have increased fire severity. We investigated the relationship between protected status and fire severity using the Random Forests algorithm applied to 1500 fires affecting 9.5 million hectares between 1984 and 2014 in pine (Pinus ponderosa, Pinus jeffreyi) and mixed-conifer forests of western United States, accounting for key topographic and climate variables. We found forests with higher levels of protection had lower severity values even though they are generally identified as having the highest overall levels of biomass and fuel loading. Our results suggest a need to reconsider current overly simplistic assumptions about the relationship between forest protection and fire severity in fire management and policy.

Toward a more ecologically informed view of severe forest fires

Article

Full-text available

Feb 2016

We use the historical presence of high-severity fire patches in mixed-conifer forests of the western United States to make several points that we hope will encourage development of a more ecologically informed view of severe wildland fire effects. First, many plant and animal species use, and have sometimes evolved to depend on, severely burned forest conditions for their persistence. Second, evidence from fire history studies also suggests that a complex mosaic of severely burned conifer patches was common historically in the West. Third, to maintain ecological integrity in forests born of mixed-severity fire, land managers will have to accept some severe fire and maintain the integrity of its aftermath. Lastly, public education messages surrounding fire could be modified so that people better understand and support management designed to maintain ecologically appropriate sizes and distributions of severe fire and the complex early-seral forest conditions it creates.

Wildland fire emissions, carbon, and climate: Seeing the forest and the trees – A cross-scale assessment of wildfire and carbon dynamics in fire-prone, forested ecosystems

Article

Full-text available

Jan 2014
FOREST ECOL MANAG

Wildfires are an important component of the terrestrial carbon cycle and one of the main pathways for movement of carbon from the land surface to the atmosphere. Fires have received much attention in recent years as potential catalysts for shifting landscapes from carbon sinks to carbon sources. Unless structural or functional ecosystem shifts occur, net carbon balance in fire-adapted systems at steady state is zero when assessed over the entire post-fire successional sequence and at landscape scales. When evaluated at fine spatial scales and over short periods of time, however, wildfires may seem to release more carbon to the atmosphere than remains on site. Measurements of wildfire carbon emissions are thus highly biased by the spatial and temporal scales that bound them, and may over- or under-estimate carbon source-sink dynamics that provide critical feedbacks to the climate system. This synthesis paper provides a description of the ecological drivers of wildfires and carbon in forested ecosystems across the spatial and temporal scales at which system drivers (e.g., climate, weather), behaviors (e.g., wildfire occurrence, spread, intensity), and resulting patterns (e.g., vegetation composition and structure, carbon emissions) occur and interact. Improved understanding of these relationships is critical if we are to anticipate and respond to major changes in the global earth system expected in the coming decades and centuries.

Is fire severity increasing in the Sierra Nevada, California, USA?

Article

Full-text available

Jan 2014
INT J WILDLAND FIRE

Research in the Sierra Nevada range of California, USA, has provided conflicting results about current trends of high-severity fire. Previous studies have used only a portion of available fire severity data, or considered only a portion of the Sierra Nevada. Our goal was to investigate whether a trend in fire severity is occurring in Sierra Nevada conifer forests currently, using satellite imagery. We analysed all available fire severity data, 1984-2010, over the whole ecoregion and found no trend in proportion, area or patch size of high-severity fire. The rate of high-severity fire has been lower since 1984 than the estimated historical rate. Responses of fire behaviour to climate change and fire suppression may be more complex than assumed. A better understanding of spatiotemporal patterns in fire regimes is needed to predict future fire regimes and their biological effects. Mechanisms underlying the lack of an expected climate-and time since fire-related trend in high-severity fire need to be identified to help calibrate projections of future fire. The effects of climate change on high-severity fire extent may remain small compared with fire suppression. Management could shift from a focus on reducing extent or severity of fire in wildlands to protecting human communities from fire.

Using Fire to Increase the Scale, Benefits, and Future Maintenance of Fuels Treatments

Article

Full-text available

Oct 2012
J FOREST

The USDA Forest Service is implementing a new planning rule and starting to revise forest plans for many of the 155 National Forests. In forests that historically had frequent fire regimes, the scale of current fuels reduction treatments has often been too limited to affect fire severity and the Forest Service has predominantly focused on suppression. In addition to continued treatment of the wildland urban interface, increasing the scale of low- and moderate-severity fire would have substantial ecological and economics benefits if implemented soon. We suggest National Forests identify large contiguous areas to concentrate their fuels reduction efforts, and then turn treated firesheds over to prescribed and managed wildfire for future maintenance. A new round of forest planning provides an opportunity to identify and overcome some of the current cultural, regulatory, and institutional barriers to increased fire use that we discuss.

Learning to coexist with wildfire

Article

Full-text available

Nov 2014
NATURE

The impacts of escalating wildfire in many regions — the lives and homes lost, the expense of suppression and the damage to ecosystem services — necessitate a more sustainable coexistence with wildfire. Climate change and continued development on fire-prone landscapes will only compound current problems. Emerging strategies for managing ecosystems and mitigating risks to human communities provide some hope, although greater recognition of their inherent variation and links is crucial. Without a more integrated framework, fire will never operate as a natural ecosystem process, and the impact on society will continue to grow. A more coordinated approach to risk management and land-use planning in these coupled systems is needed.

Fire and fish: A synthesis of observation and experience

Chapter

Jan 2012

CONSERVATION OF AQUATIC AND FISHERY RESOURCES IN THE PACIFIC NORTHWEST: Implications of New Science for the Aquatic Conservation Strategy of the Northwest Forest Plan

Technical Report

Full-text available

Aug 2014

Twenty years have elapsed since a major science synthesis and planning effort led to adoption of the Aquatic Conservation Strategy (ACS) of the Northwest Forest Plan (NFP) in 1994. Their purpose was to protect and restore riparian and aquatic ecosystems on Pacific Northwest federal forest lands and to ensure that forest management plans achieved legally required and socially desired multiple use objectives, including protection of water quality, aquatic and wildlife resources. In this paper, we review relevant science emerging since 1993 to assess whether proposed changes to the ACS, including reduced riparian reserve protections and a substantially lowered burden of proof for watershed-disturbing activities, are scientifically justified. Observed and anticipated effects of climate change, and of cumulative anthropogenic stressors operating in the nonfederal lands surrounding NFP lands strongly indicate the need to strengthen, not weaken key ACS protections. Roads and ground disturbance associated with mechanical thinning and fuels reduction activities, especially within Riparian Reserves, cause adverse environmental impacts that generally offset or exceed presumed restorative benefits. Headwater streams warrant wider riparian forest buffers than current ACS provisions to ensure effective retention of sediment and nutrients derived from upslope logging, fire, and landslides. Widespread and sustained ecological harm caused by roads is now widely recognized, and ACS measures should be strengthened to more effectively arrest and reduce road impacts in all catchments. Grazing, mining, post-disturbance logging (e.g., fire salvage), water withdrawal, and aerial application of toxic chemicals can cause both acute and chronic harm to aquatic ecosystems. Existing ACS standards and guidelines would need to be strengthened to more effectively control these impacts. A more thorough and current scientific review and synthesis by federal agencies to inform a future ACS is long overdue. Unfortunately, no such review has occurred, while recent agency and legislative proposals would substantially reduce protective provisions of the ACS and NFP by increasing the extent of logging and other mechanized forest management, such as fuels treatments.

Aligning ecology and markets in the forest carbon cycle

Article

Full-text available

Feb 2013

A forest carbon (C) offset is a quantifiable unit of C that is commonly developed at the local or regional project scale and is designed to counterbalance anthropogenic C emissions by sequestering C in trees. In cap-and-trade programs, forest offsets have market value if the sequestered C is additional (more than would have occurred in the absence of the project) and permanent (sequestered within the project boundary for a specified period of time). Local management and ecological context determine the rate of C sequestration, risk of loss, and hence the market value. An understanding of global C dynamics can inform policy but may not be able to effectively price an ecosystem service, such as C sequestration. Appropriate pricing requires the assistance of ecologists to assess C stock abundance and stability over spatial and temporal scales appropriate for the regional market. We use the risk that sequestered C will be emitted as a result of wildfire (reversal risk) to show how ecological context can influence market valuation in offset programs.

Effectiveness of fuel treatments for mitigating wildfire risk and sequestering forest carbon: A case study in the Lake Tahoe Basin

Article

Jul 2014
FOREST ECOL MANAG

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

Article

Full-text available

Jan 2013

In many U. S. federally designated wilderness areas, wildfires are likely to burn of their own accord due to favorable management policies and remote location. Previous research suggested that limitations on fire size can result from the evolution of natural fire regimes, specifically in places where fuels were recently reduced by previous burning. To explore the broader-scale importance of fire management on wilderness landscapes, we selected three study regions representing diverse ecosystems in the western U. S. and modeled the change in fire size distributions across a gradient defined by wilderness/non-wilderness boundaries. For randomly selected locations across the gradient, we derived a scaling parameter (alpha) using fire size-frequency data for public lands (1984-2007); the parameter reflected the magnitude of change in the right tail of the fire size distribution where the largest fires reside. We then used quantile regression to model changes in a across the wilderness gradient, interpreting the results in terms of constraints on the relative role of large fires in structuring the fire size distribution. In the Southwest study region, the influence of large fires on size distributions decreased across the gradient toward wilderness at some places, suggesting that increased occurrence of natural burning, favored by wilderness management, led to limitations on fire sizes within recent timeframes. In contrast, we were unable to support the expectation that wilderness fire management limits the role of large fires in the Sierra Nevada and Northern Rockies study regions. Rather, the predominance of large fires increased toward wilderness interiors. Among spatial climate and topographic roughness variables included in our study, only winter and fire season precipitation limited fire size in the Northern Rockies, whereas several constraints on large fire occurrence operated in other regions. In southwestern ecosystems, evidence is needed to document stability in fire size distributions through time. In ecosystems of the Sierra Nevada and Northern Rockies, a longer temporal extent of observations may better match scales of disturbance and recovery. Our findings reflect the role of wilderness in addressing a fire deficit which has resulted from strong human influences on forests and fires over the past 150 years.

Examining Historical and Current Mixed-Severity Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

Article

Full-text available

Feb 2014
PLOS ONE

There is widespread concern that fire exclusion has led to an unprecedented threat of uncharacteristically severe fires in ponderosa pine (Pinus ponderosa Dougl. ex. Laws) and mixed-conifer forests of western North America. These extensive montane forests are considered to be adapted to a low/moderate-severity fire regime that maintained stands of relatively old trees. However, there is increasing recognition from landscape-scale assessments that, prior to any significant effects of fire exclusion, fires and forest structure were more variable in these forests. Biota in these forests are also dependent on the resources made available by higher-severity fire. A better understanding of historical fire regimes in the ponderosa pine and mixed-conifer forests of western North America is therefore needed to define reference conditions and help maintain characteristic ecological diversity of these systems. We compiled landscape-scale evidence of historical fire severity patterns in the ponderosa pine and mixed-conifer forests from published literature sources and stand ages available from the Forest Inventory and Analysis program in the USA. The consensus from this evidence is that the traditional reference conditions of low-severity fire regimes are inaccurate for most forests of western North America. Instead, most forests appear to have been characterized by mixed-severity fire that included ecologically significant amounts of weather-driven, high-severity fire. Diverse forests in different stages of succession, with a high proportion in relatively young stages, occurred prior to fire exclusion. Over the past century, successional diversity created by fire decreased. Our findings suggest that ecological management goals that incorporate successional diversity created by fire may support characteristic biodiversity, whereas current attempts to "restore" forests to open, low-severity fire conditions may not align with historical reference conditions in most ponderosa pine and mixed-conifer forests of western North America.

Societal benefits from wildfire mitigation activities through payments for watershed services: Insights from Colorado

Article

Feb 2022
FOREST POLICY ECON

Payments for watershed services (PWS) programs are becoming a popular governance approach in the western United States (US) to fund forest management aimed at source water protection. In this paper we conduct a cost-benefit analysis (CBA) of one of the first collaboratively funded PWS programs in the US, located in the municipal watersheds servicing Denver, Colorado. We combine wildfire modeling, sediment modeling, and primary and secondary data on economic values to quantify the impact of the program on protecting multiple values at risk. Our results show that while the program has led to diverse societal benefits, it is only economically efficient (benefit-cost ratio greater than one) when all co-benefits beyond source water protection are considered, and fuels treatments are assumed to encounter wildfire. When the probability of wildfire is accounted for, economic benefits would need to be triple what was estimated in our analysis to achieve economic efficiency. Our findings suggest that improving spatial prioritization of interventions would increase economic benefits and better data on treatment placement and costs would help facilitate future CBA of PWS programs focused on wildfire mitigation.

Fuel Dynamics and Management

Chapter

Sep 2021

Fuels influence fire ignition, spread, intensity, and severity. Thus, fuels link fire behavior and fire effects. Fuels are central to our book, Fire science from chemistry to landscape management. We address how scientists and managers describe types of fuels, assess the amount of fuels (called fuel load) and characterize fuelbeds. The amount and type of fuel change with deposition, decomposition, disturbance, and vegetation dynamics. Fuel moisture too is dynamic. The moisture of live and dead fuels is critical to how readily fuels burn and how much fuel is consumed by fires. Lastly, we discuss fuels management, starting with strategies and principles, and continuing through different methods, including mechanical treatments and prescribed burning. Managers use fuels treatments to reduce or rearrange fuels to reduce potential fire spread and intensity. Fire fighters can use treatments in their fire suppression efforts. Fuels treatments are often part of ecological restoration to enhance resilience of forests and woodlands to future fires. Fuels management decreases burn severity, and not just when fires burn under moderate environmental conditions. Fuels treatments are less effective when challenged by fires burning under extreme conditions and as vegetation regrows. Strategic placement of fuels treatments can increase their effectiveness. Through our explanations of concepts and examples from forests, woodlands, and shrublands from around the world, readers develop a nuanced understanding of fuels dynamics and management. We discuss current issues such as where and how fuels treatments are effective, arguing that fuels treatments will still be useful in fire management even as climate changes. Readers can use the two interactive spreadsheets reinforce learning about fuel dynamics and crown fire mitigation.

Spatial planning of fire-agency stations as a function of wildfire likelihood in Thasos, Greece

Article

Full-text available

Apr 2020
SCI TOTAL ENVIRON

Even though wildfires constitute a natural phenomenon, they may have severe implications with respect to the socioeconomic structure of the affected population and the ecological wealth of a territory, especially when they burn under high intensities. Timing of the initial attack is thus crucial to fire control in areas that fires are considered to be under high threat of burning. The aim of this paper is to investigate the combined use of simulation modeling and spatial optimization to assess the pre-positioning of fire-management resources on a small Greek island, Thasos, based on the current and desired fire agency capabilities, maximization of environmental protection, and rationalization of financial resources. The estimation of burn probability (BP) depicted specific areas of high fire hazard in the southern, central, and western part of the island, where essential preventive measures should be undertaken. Based on this result, BP was then used as a primary input for the assessment of optimal locations of fire operation agencies in order to achieve the maximal coverage under certain (already available) and minimum number of fire-fighting vehicles in different time windows. The results generated three differentiated optimal location schemes [8 available vehicles within either 10 (immediate response time) or 31 min (average response time) with the current fire resources; 19 and 2 required vehicles within 10 and 31 min, respectively, based on a minimum number of fire resources]. This type of information enables us to propose a relocation of the current fire agency in a southern town of the island. The flexibility and interaction of the models provide a framework for appropriate decision making under a set of political and financial constraints.

Framework for Identifying Preferred Sustainable Management Actions with Application to Forest Fuel Treatment

Chapter

Jan 2020

Tony Prato

A conceptual framework is presented for identifying preferred feasible and sustainable management actions for a coupled human and natural system. The framework involves: (1) determining operationally and financially feasible management actions; (2) selecting and estimating management objectives for those actions; (3) using the weak or strong sustainability criterion to identify feasible management actions that are sustainable; (4) assigning weights to management objectives; and (5) ranking feasible and sustainable management actions. Management actions, objectives, and weights are selected by the manager. Management actions are ranked using a multiple objective evaluation method and utility values estimated with the utility function U(\( {\sum}_{i=1}^n{w}_i{V}_{ij} \)), where i designates management objective, j designates management action, wi is the weight assigned to the ith management objective, Vij is the estimated value of the ith management objective for the jth management action, and \( {\sum}_{i=1}^n{w}_i\,{=}\,1 \). Management objectives are simulated or estimated using biophysical and economic data and models. An empirical application of the framework is presented that uses the Stochastic Efficiency with Respect to a Function method and utility values to rank three preselected fuel treatment strategies and determines preferred treatment strategies for U.S. Forest Service land in Flathead County, Montana for two risk attitudes (i.e., almost risk neutral and strongly risk averse).

Carbon Dynamics of Mixed- and High-Severity Wildfires: Pyrogenic CO2 Emissions, Postfire Carbon Balance, and Succession

Article

Dec 2015

Stephen R. Mitchell

Among the concerns raised by climatic change is the potential for the additional release of carbon dioxide as a result of biomass combustion. Most of the carbon emissions from wildfires are from the combustion of litter, duff, and small woody debris, whereas most, if not all, of the biomass stored in the boles of large trees is not combusted. Consequently, most of the carbon stored in forests remains unconsumed, even by high-severity wildfires. Thus the application of fuel reduction treatments, while sometimes effective in reducing fire severity and carbon emissions, nearly always result in a net reduction in carbon storage. Postfire carbon emissions from the decomposition of fire-killed biomass can continue for decades, but effects of forest regrowth can exceed the losses of carbon from biomass combustion and the decomposition of fire-killed biomass within 5-50 years, depending on the ecosystem. © 2015 by Dominick A. DellaSala and Chad T. Hanson. Published by Elsevier Inc. All rights reserved.

Crater Lake National Park: Natural Resource Condition Assessment

Technical Report

Full-text available

Jan 2013

We compiled existing data and information to characterize the condition and trends in high priority natural resources in Crater Lake National Park. This report, and the spatial datasets provided with it, is intended to inform and support park managers and scientists in developing recommendations for improving or maintaining natural resource conditions in the park. It also can assist park resource managers in meeting the reporting requirements of the Government Performance Results Act and Office of Management and Budget. In attempts to describe the current condition and trends of the park’s natural resources, we followed generally the Environmental Protection Agency’s “Framework for Assessing and Reporting on Ecological Condition” (Young and Sanzone 2002). Specifically, we first identified seven natural resource themes considered by this park’s managers and scientists to be most important. They are:  Precipitation, Temperature, Snowpack, and Lake Levels  Surface Water Quality  Aquatic Life  Terrestrial Vegetation  Wildlife  Air Quality  Natural Quality of the Park Experience We identified 24 indicators to evaluate these seven resource concerns. For each indicator we then attempted to define reference conditions to which we could compare present conditions. Making that comparison, we described the condition of each indicator as “Good,” “Somewhat Concerning,” “Significant Concern,” or “Indeterminate.” We described each indicator’s trend as “Improving,” “Somewhat Concerning,” “Significant Concern,” or “Indeterminate.” In each instance where we applied these terms, we also described (as high, moderate, or low) the certainty associated with our estimate. Where reference conditions that were the basis for our comparisons lacked quantitative standards, we based the assessment on qualitative descriptions of least-altered resource conditions derived from historical accounts, scientific literature, and professional opinion. Applying the 24 indicators, we determined that the condition of three indicators is of Significant Concern in this park. Those are: the distribution of forest stand ages, fire rotations, and extent of invasive pathogens. The reduced frequency of fire in some parts of the park has created conditions that are at the extreme end of the natural age distribution for the park’s forest types. This can restrict the park’s capacity to effectively support the region’s wildlife and plant diversity. We assigned a rating of “Somewhat Concerning” to seven indicators:  Changes in Productivity and Diversity in Non-caldera Water Bodies  Changes in Ecologically Harmful Aquatic Species xiv  Recovery of Disturbed Areas  Diversity of Native Terrestrial Wildlife Species; Rare Species  Connectivity and Extent of Important Terrestrial Habitats  Deposition of Airborne Contaminants  Ozone Levels Park managers have limited capacity to influence the condition of the last three indicators. However, NPS has had some success working with policy makers and regulators to enforce stricter standards when park data indicated air quality problems resulting from local sources. The condition of a plurality of the indicators (11), including the condition of the caldera lake itself, was rated “Good.” However, information was insufficient to rate the present condition or trends of four important indicators throughout all areas of the park:  Annual Depth, Volume, and Persistence of Snowpack  Water Quality in Non-caldera Water Bodies  Rare Plants and Native Plant Diversity  Dark Night Sky Information sufficient to estimate trends was lacking for 16 of the 24 indicators, and none of the trends calculations were considered to have a high degree of certainty.

NCA3 Full Report 07 Forestry HighRes

Data

Full-text available

Oct 2014

Climate change and forests

Conference Paper

Full-text available

Aug 2014

Trees in U.S. cities, the wildland-urban interface and rural areas are responding to climate change. Longer growing seasons help trees grow faster in many areas, but simultaneously result in longer periods of water stress. Western forests are particularly vulnerable to increasing wildfire and insect outbreaks. In rural areas especially, the demand for wood products, watersheds for clean water, and recreation opportunities interact with emerging bioenergy markets, potential for carbon credits, and changing private forest ownerships. These factors along with climate-induced risks to forests and the perceptions of public land management make the future use of forests a challenging public issue.

Forests

Chapter

Full-text available

May 2014

Key Messages 1. Climate change is increasing the vulnerability of many forests to ecosystem changes and tree mortality through fire, insect infestations, drought, and disease outbreaks. 2. U.S. forests and associated wood products currently absorb and store the equivalent of about 16% of all carbon dioxide (CO2) emitted by fossil fuel burning in the U.S. each year. Climate change, combined with current societal trends in land use and forest management, is projected to reduce this rate of forest CO2 uptake. 3. Bioenergy could emerge as a new market for wood and could aid in the restoration of forests killed by drought, insects, and fire. 4. Forest management responses to climate change will be influenced by the changing nature of private forestland ownership, globalization of forestry markets, emerging markets for bioenergy, and U.S. climate change policy.

Science basis for changing forest structure to modify wildfire behavior and severity

Technical Report

Full-text available

Jan 2004

Fire, other disturbances, physical setting, weather, and climate shape the structure and function of forests throughout the Western United States. More than 80 years of fire research have shown that physical setting, fuels, and weather combine to determine wildfire intensity (the rate at which it consumes fuel) and severity (the effect fire has on vegetation, soils, buildings, watersheds, and so forth). As a result of fire exclusion, timber harvesting, and livestock grazing, millions of acres of forestlands (mainly in dry forests dominated by ponderosa pine and/or Douglas-fir) contain a high accumulation of flammable fuels compared to conditions prior to the 20th century. Forests with high stem density and fuel loading combined with extreme fire weather conditions have led to severe and large wildfires (such as those seen in the summers of 2000 and 2002 and the fall of 2003) that have put a number of important values at risk. Although homes in the path of a wildfire are perhaps the most immediately recognized value, these wildfires also put numerous other human and ecological values at risk, such as power grids, drinking water supplies, firefighter safety, critical habitat, soil productivity, and air quality. For a given set of weather conditions, fire behavior is strongly influenced by stand and fuel structure. Crown fires in the dry forest types represent an increasing challenge for fire management as well as a general threat to the ecology of these forests and the closely associated human values. Crown fires are dependent on the sequence of available fuels starting from the ground surface to the canopy. Limiting crown fire in these forests can, thus, be accomplished by fuel management actions that first reduce surface and ladder fuels before manipulating canopy fuels. Reducing crown fire and wildland fire growth across landscapes decreases the chances of developing large wildfires that affect human values adjacent to forested areas. However, a narrow focus on minimizing crown fire potential will not necessarily reduce the damage to homes and ecosystems when fires do occur there. Homes are often ignited by embers flying far from the fire front, and by surface fires. Fire effects on ecosystems can also occur during surface fires where fine fuels and deep organic layers are sufficient to generate high temperatures for long periods. Fuel treatments can help produce forest structures and fuel characteristics that then reduce the likelihood that wildfires will cause large, rapid changes in biophysical conditions. Fuel treatments can also help modify fire behavior sufficiently so that some wildfires can be suppressed more easily. Subsequent, sustained fuel treatments can maintain these conditions. Different fuel reduction methods target different components of the fuel bed. Thinning mainly affects standing vegetation, and other types of fuel treatments such as prescribed fire and pile burning woody fuels are needed to modify the combustion environment of surface fuels. In forests that have not experienced fire for many decades, multiple fuel treatments-that is, thinning and surface fuel reduction-may be required to significantly affect crown fire and surface fire hazard. Fuel treatments cannot guarantee benign fire behavior but can reduce the probability that extreme fire behavior will occur. Fuel treatments can be designed to restore forest conditions to a more resilient and resistant condition than now exists in many forests, and subsequent management could maintain these conditions, particularly in dry forests (ponderosa pine and Douglas-fir) where crown fires were infrequent. The degree of risk reduction will depend to some degree on the level of investment, social and economic acceptability of treatments, and concurrent consideration of other resource values (for example, wildlife). This report describes the kinds, quality, amount, and gaps of scientific knowledge for making informed decisions on fuel treatments used to modify wildfire behavior and effects in dry forests of the interior Western United States (especially forests dominated by ponderosa pine and Douglas-fir). A review of scientific principles and applications relevant to fuel treatment primarily for the dry forests is provided for the following topics: fuels, fire hazard, fire behavior, fire effects, forest structure, treatment effects and longevity, landscape fuel patterns, and scientific tools useful for management and planning.

Fuel accumulation rates after prescribed fires in Yosemite National Park

Conference Paper

Full-text available

Apr 1987

Long-term sedimentation effects of different patterns of timber harvesting

Article

Full-text available

Jan 1991

It is impractical to address the long-term effect of forest man- agement strategies on erosion, sedimentation, and the resultant damage to fish habitat experimentally because to do so would require studying large watersheds for a century or more. Monte Carlo simulations were conducted on three hypothetical 10 000 ha, fifth-order forested watersheds. One wa- tershed was left undisturbed, one was completely clearcut and roaded in a decade, and one was cut at the rate of 1% each year. Each cutting strategy was repeated in succeeding centuries.

Fire and Aquatic Ecosystems in Forested Biomes of North America

Article

Full-text available

Mar 1999

Robert E. Gresswell

Synthesis of the literature suggests that physical, chemical, and biological elements of a watershed interact with long-term climate to influence fire regime, and that these factors, in concordance with the postfire vegetation mosaic, combine with local-scale weather to govern the trajectory and magnitude of change following a fire event. Perturbation associated with hydrological processes is probably the primary factor influencing postfire persistence of fishes, benthic macroin vertebrates, and diatoms in fluvial systems. It is apparent that salmonids have evolved strategies to survive perturbations occurring at the frequency of wildland fires (100-102 years), but local populations of a species may be more ephemeral. Habitat alteration probably has the greatest impact on individual organisms and local populations that are the least mobile, and reinvasion will be most rapid by aquatic organisms with high mobility. It is becoming increasingly apparent that during the past century fire suppression has altered fire regimes in some vegetation types, and consequently, the probability of large stand-replacing fires has increased in those areas. Current evidence suggests, however, that even in the case of extensive high-severity fires, local extirpation of fishes is patchy, and recolonization is rapid. Lasting detrimental effects on fish populations have been limited to areas where native populations have declined and become increasingly isolated because of anthropogenic activities. A strategy of protecting robust aquatic communities and restoring aquatic habitat structure and life history complexity in degraded areas may be the most effective means for insuring the persistence of native biota where the probability of large-scale fires has increased.

How did prefire treatments affect the Biscuit Fire?

Article

Full-text available

Jan 2005

The Effects of Postfire Salvage Logging on Aquatic Ecosystems in the American West

Article

Full-text available

Nov 2004
BIOSCIENCE

Recent changes in the forest policies, regulations, and laws affecting public lands encourage postfire salvage logging, an activity that all too often delays or prevents recovery. In contrast, the 10 recommendations proposed here can improve the condition of watersheds and aquatic ecosystems. Keywords: aquatic ecosystems, postfire salvage logging, public land management, salmonids, western forests

Sediment Production From Forest Road Surfaces

Article

Full-text available

Nov 1984

Erosion on roads is an important source of fine-grained sediment in streams draining logged basins of the Pacific Northwest. Runoff rates and sediment concentrations from 10 road segments subject to a variety of traffic levels were monitored to produce sediment rating curves and unit hydrographs for different use levels and types of surfaces. These relationships are combined with a continuous rainfall record to calculate mean annual sediment yields from road segments of each use level. A heavily used road segment in the field area contributes 130 times as much sediment as an abandoned road. A paved road segment, along which cut slopes and ditches are the only sources of sediment, yields less than 1% as much sediment as a heavily used road with a gravel surface.

Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada

Article

Full-text available

Jan 1355

Patterns of native and alien plant diversity in response to disturbance were examined along an elevational gradient in blue oak savanna, chaparral, and coniferous forests. Total species richness, alien species richness, and alien cover declined with ele-vation, at scales from 1 to 1000 m 2 . We found no support for the hypothesis that community diversity inhibits alien invasion. At the 1-m 2 point scale, where we would expect competitive interactions between the largely herbaceous flora to be most intense, alien species richness as well as alien cover increased with increasing native species richness in all communities. This suggests that aliens are limited not by the number of native competitors, but by resources that affect establishment of both natives and aliens. Blue oak savannas were heavily dominated by alien species and consistently had more alien than native species at the 1-m 2 scale. All of these aliens are annuals, and it is widely thought that they have displaced native bunchgrasses. If true, this means that aliens have greatly increased species richness. Alternatively, there is a rich regional flora of native annual forbs that could have dominated these grasslands prior to displacement by alien grasses. On our sites, livestock grazing increased the number of alien species and alien cover only slightly over that of sites free of livestock grazing for more than a century, indicating some level of permanency to this invasion. In chaparral, both diversity and aliens increased markedly several years after fire. In-vasive species are rare in undisturbed shrublands, and alien propagules fail to survive the natural crown fires in these ecosystems. Thus, aliens necessarily must colonize after fire and, as a consequence, time since fire is an important determinant of invasive presence. Blue oak savannas are an important propagule source for alien species because they maintain permanent populations of all alien species encountered in postfire chaparral, and because the vegetation mosaic in this region places them in proximity to chaparral. The speed at which alien propagules reach a burned site and the speed at which the shrublands return to their former closed-canopy condition determine alien invasion. Frequent burning of this vegetation alters the balance in favor of alien invasion. In the higher-elevation coniferous forests, species diversity was a function of fire severity and time since fire. High-intensity fires create gaps that decrease canopy coverage and increase light levels and nutrients for an ephemeral successional flora. Few species have persistent seed banks, so the time since fire is an important determinant of colonization success. There was a highly significant interaction between fire severity and time since fire for understory cover, species richness, and alien richness and cover. Understory was sparse in the first year after fire, particularly in low-severity burns, and increased substantially several years after fire, particularly on high-severity burns. Both fire severity and time since fire affected alien species richness and dominance. Coniferous forests had about one-third as many alien species as the foothill oak savannas, and fewer than half of the species were shared between these communities. Unburned coniferous forests were largely free of alien species, whereas some burned sites had a significant alien presence, which presents a challenge for fire restoration of these forests.

Key issues in fire regime research for fuels management and ecological restoration

Article

Full-text available

May 2003

Thomas T Veblen

The basic premise behind many projects aimed at wildfire hazard reduction and ecological restoration in forests of the western United States is the idea that unnatural fuel buildup has resulted from suppression of formerly frequent fires. This premise and its implications need to be critically evaluated by conducting area-specific research in the forest ecosystems targeted for fuels or ecological restoration projects. Fire regime researchers need to acknowledge the limitations of fire history methodology and avoid over-reliance on summary fire statistics such as mean fire interval and rotation period. While fire regime research is vitally important for informing decision making in the areas of wildfire hazard mitigation and ecological restoration, there is much need for improving the way researchers communicate their results to managers and the way managers use this information.

Ecological Restoration of Southwestern Ponderosa Pine Ecosystems: A Broad Perspective

Article

Full-text available

Jan 2005

The purpose of this paper is to promote a broad and flexible perspective on ecological restoration of Southwestern (U.S.) ponderosa pine forests. Ponderosa pine forests in the region have been radically altered by Euro-American land uses, including livestock grazing, fire suppression, and logging. Dense thickets of young trees now abound, oldgrowth and biodiversity have declined, and human and ecological communities are increasingly vulnerable to destructive crown fires. A consensus has emerged that it is urgent to restore more natural conditions to these forests. Efforts to restore Southwestern forests will require extensive projects employing varying combinations of young-tree thinning and reintroduction of low-intensity fires. Treatments must be flexible enough to recognize and accommodate: high levels of natural heterogeneity; dynamic ecosystems; wildlife and other biodiversity considerations; scientific uncertainty; and the challenges of on-the-ground implementation. Ecological restoration should reset ecosystem trends toward an envelope of ‘‘natural variability,’’ including the reestablishment of natural processes. Reconstructed historic reference conditions are best used as general guides rather than rigid restoration prescriptions. In the long term, the best way to align forest conditions to track ongoing climate changes is to restore fire, which naturally correlates with current climate. Some stands need substantial structural manipulation (thinning) before fire can safely be reintroduced. In other areas, such as large wilderness and roadless areas, fire alone may suffice as the main tool of ecological restoration, recreating the natural interaction of structure and process. Impatience, overreaction to crown fire risks, extractive economics, or hubris could lead to widespread application of highly intrusive treatments that may further damage forest ecosystems. Investments in research and monitoring of restoration treatments are essential to refine restoration methods. We support the development and implementation of a diverse range of scientifically viable restoration approaches in these forests, suggest principles for ecologically sound restoration that immediately reduce crown fire risk and incrementally return natural variability and resilience to Southwestern forests, and present ecological perspectives on several forest restoration approaches.

Fire Severity in Conifer Forests of the Sierra Nevada, California

Article

Full-text available

Nov 2006

Natural disturbances are an important source of environmental heterogeneity that have been linked to species diversity in ecosystems. However, spatial and temporal patterns of disturbances are often evaluated separately. Consequently, rates and scales of existing disturbance processes and their effects on biodiversity are often uncertain. We have studied both spatial and temporal patterns of contemporary fires in the Sierra Nevada Mountains, California, USA. Patterns of fire severity were analyzed for conifer forests in the three largest fires since 1999. These fires account for most cumulative area that has burned in recent years. They burned relatively remote areas where there was little timber management. To better characterize high-severity fire, we analyzed its effect on the survival of pines. We evaluated temporal patterns of fire since 1950 in the larger landscapes in which the three fires occurred. Finally, we evaluated the utility of a metric for the effects of fire suppression. Known as Condition Class it is now being used throughout the United States to predict where fire will be uncharacteristically severe. Contrary to the assumptions of fire management, we found that high-severity fire was uncommon. Moreover, pines were remarkably tolerant of it. The wildfires helped to restore landscape structure and heterogeneity, as well as producing fire effects associated with natural diversity. However, even with large recent fires, rates of burning are relatively low due to modern fire management. Condition Class was not able to predict patterns of high-severity fire. Our findings underscore the need to conduct more comprehensive assessments of existing disturbance regimes and to determine whether natural disturbances are occurring at rates and scales compatible with the maintenance of biodiversity.

Basic principles of forest fuel reduction treatments

Article

Full-text available

Jun 2005
FOREST ECOL MANAG

Successful fire exclusion in the 20th century has created severe fire problems across the West. Not every forest is at risk of uncharacteristically severe wildfire, but drier forests are in need of active management to mitigate fire hazard. We summarize a set of simple principles important to address in fuel reduction treatments: reduction of surface fuels, increasing the height to live crown, decreasing crown density, and retaining large trees of fire-resistant species. Thinning and prescribed fire can be useful tools to achieve these objectives. Low thinning will be more effective than crown or selection thinning, and management of surface fuels will increase the likelihood that the stand will survive a wildfire. Five empirical examples of such treatment are discussed: Hayfork fires, California, 1987; Tyee fire, Washington, 1994; Megram fire, California, 1999; Hayman fire, Colorado, 2002; and the Cone fire, California, 2002. Applying treatments at an appropriate landscape scale will be critical to the success of fuel reduction treatments in reducing wildfire losses in Western forests.

The role of climate and vegetation change in shaping past and future fire regimes in the northwestern US and implications for ecosystem management

Article

Full-text available

Jun 2003
FOREST ECOL MANAG

Fire is an important part of the disturbance regimes of northwestern US forests and its role in maintaining and altering forest vegetation is evident in the paleoecological record of the region. Long-term reconstructions of Holocene fire regimes, provided by the analysis of charcoal, pollen, and other fire proxies in a network of lake records, indicate that the Pacific Northwest and summer-dry regions of the northern Rocky Mountains experienced their highest fire activity in the early Holocene (11,000–7000 years ago) and during the Medieval Warm Period (ca. 1000 years ago) when drought conditions were more severe than today. In contrast, in summer-wet areas of the northern Rocky Mountains, the period of highest fire activity was registered in the last 7000 years when dry woodland vegetation developed. When synthesized across the entire northwestern US, the paleoecological record reveals that past and present fire regimes are strongly controlled by climate changes occurring on multiple time scales. The scarcity of fires in the 20th century in some northwestern US ecosystems may be the result of successful fire suppression policies, but in wetter forests this absence is consistent with long-term fire regime patterns. In addition, simulations of potential future climate and vegetation indicate that future fire conditions in some parts of the northwestern US could be more severe than they are today. The Holocene record of periods of intensified summer drought is used to assess the nature of future fire–climate–vegetation linkages in the region.

Managing fire-prone forests in the Western United States

Article

Full-text available

Nov 2006

The management of fire-prone forests is one of the most controversial natural resource issues in the US today, particularly in the west of the country. Although vegetation and wildlife in these forests are adapted to fire, the historical range of fire frequency and severity was huge. When fire regimes are altered by human activity, major effects on biodiversity and ecosystem function are unavoidable. We review the ecological science relevant to developing and implementing fire and fuel management policies for forests before, during, and after wildfires. Fire exclusion led to major deviations from historical variability in many dry, low-elevation forests, but not in other forests, such as those characterized by high severity fires recurring at intervals longer than the period of active fire exclusion. Restoration and management of fire-prone forests should be precautionary, allow or mimic natural fire regimes as much as possible, and generally avoid intensive practices such as post-fire logging and planting. yes

Interaction of Fire, Fuels, and Climate Across Rocky Mountain Forests

Article

Full-text available

Jul 2004

Understanding the relative influence of fuels and climate on wildfires across the Rocky Mountains is necessary to predict how fires may respond to a changing climate and to define effective fuel management approaches to controlling wildfire in this increasingly populated region. The idea that decades of fire suppression have promoted unnatural fuel accumulation and subsequent unprecedentedly large, severe wildfires across western forests has been developed primarily from studies of dry ponderosa pine forests. However, this model is being applied uncritically across Rocky Mountain forests (e.g., in the Healthy Forests Restoration Act). We synthesize current research and summarize lessons learned from recent large wildfires (the Yellowstone, Rodeo-Chediski, and Hayman fires), which represent case studies of the potential effectiveness of fuel reduction across a range of major forest types. A “one size fits all” approach to reducing wildfire hazards in the Rocky Mountain region is unlikely to be effective and may produce collateral damage in some places.

Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity

Article

Full-text available

Sep 2006
SCIENCE

Western United States forest wildfire activity is widely thought to have increased in recent decades, yet neither the extent of recent changes nor the degree to which climate may be driving regional changes in wildfire has been systematically documented. Much of the public and scientific discussion of changes in western United States wildfire has focused instead on the effects of 19th- and 20th-century land-use history. We compiled a comprehensive database of large wildfires in western United States forests since 1970 and compared it with hydroclimatic and land-surface data. Here, we show that large wildfire activity increased suddenly and markedly in the mid-1980s, with higher large-wildfire frequency, longer wildfire durations, and longer wildfire seasons. The greatest increases occurred in mid-elevation, Northern Rockies forests, where land-use histories have relatively little effect on fire risks and are strongly associated with increased spring and summer temperatures and an earlier spring snowmelt.

Probability, Statistics, and Decision for Civil Engineers

Article

Feb 1971
TECHNOMETRICS

Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests

Article

Jan 2002
INT J WILDLAND FIRE

Fire exclusion policies have affected stand structure and wildfire hazard in north American ponderosa pine forests. Wildfires are becoming more severe in stands where trees are densely stocked with shade-tolerant understory trees. Although forest managers have been employing fuel treatment techniques to reduce wildfire hazard for decades, little scientific evidence documents the success of treatments in reducing fire severity. Our research quantitatively examined fire effects in treated and untreated stands in western United States national forests. Four ponderosa pine sites in Montana, Washington, California and Arizona were selected for study. Fuel treatments studied include: prescribed fire only, whole-tree thinning, and thinning followed by prescribed fire. On-the-ground fire effects were measured in adjacent treated and untreated forests. We developed post facto fire severity and stand structure measurement techniques to complete field data collection. We found that crown fire severity was mitigated in stands that had some type of fuel treatment compared to stands without any treatment. At all four of the sites, the fire severity and crown scorch were significantly lower at the treated sites. Results from this research indicate that fuel treatments, which remove small diameter trees, may be beneficial for reducing crown fire hazard in ponderosa pine sites.

Sediment in Streams: Sources, Biological Effects, and Control

Article

Nov 1997

Charles F. Rabeni

Uncertainty in surface-fire history: The case of ponderosa pine forests in the western United States

Article

Jul 2001

Present understanding of fire ecology in forests subject to surface fires is based on fire-scar evidence. We present theory and empirical results that suggest that fire-history data have uncertainties and biases when used to estimate the population mean fire interval (FI) or other parameters of the fire regime. First, the population mean FI is difficult to estimate precisely because of unrecorded fires and can only be shown to lie in a broad range. Second, the interval between tree origin and first fire scar estimates a real fire-free interval that warrants inclusion in mean-FI calculations. Finally, inadequate sampling and targeting of multiple-scarred trees and high scar densities bias mean FIs toward shorter intervals. In ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the western United States, these uncertainties and biases suggest that reported mean FIs of 2-25 years significantly underestimate population mean FIs, which instead may be between 22 and 308 years. We suggest that uncertainty be explicitly stated in fire-history results by bracketing the range of possible population mean FIs. Research and improved methods may narrow the range, but there is no statistical or other method that can eliminate all uncertainty. Longer mean FIs in ponderosa pine forests suggest that (i) surface fire is still important, but less so in maintaining forest structure, and (ii) some dense patches of trees may have occurred in the pre-Euro-American landscape. Creation of low-density forest structure across all parts of ponderosa pine landscapes, particularly in valuable parks and reserves, is not supported by these results.

Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests

Article

Jan 2002
INT J WILDLAND FIRE

Fire exclusion policies have affected stand structure and wildfire hazard in north American ponderosa pine forests. Wildfires are becoming more severe in stands where trees are densely stocked with shade-tolerant understory trees. Although forest managers have been employing fuel treatment techniques to reduce wildfire hazard for decades, little scientific evidence documents the success of treatments in reducing fire severity. Our research quantitatively examined fire effects in treated and untreated stands in western United States national forests. Four ponderosa pine sites in Montana, Washington, California and Arizona were selected for study. Fuel treatments studied include: prescribed fire only, whole-tree thinning, and thinning followed by prescribed fire. On- the-ground fire effects were measured in adjacent treated and untreated forests. We developed post facto fire severity and stand structure measurement techniques to complete field data collection. We found that crown fire severity was mitigated in stands that had some type of fuel treatment compared to stands without any treatment. At all four of the sites, the fire severity and crown scorch were significantly lower at the treated sites. Results from this research indicate that fuel treatments, which remove small diameter trees, may be beneficial for reducing crown fire hazard in ponderosa pine sites. Additional keywords: Pinus ponderosa; Montana; Washington; California; Arizona; fuel treatment; crown fire. W F0 104 5 J. P ollet and P. N. Om i Th inn ing , presc ri bed bu rning an d crow n f i re sev erity in p on deros a pine for e st s

Evaluation of the Efficacy of Forest Manipulations Still Needed

Article

Jan 2009

JONATHAN J. RHODES

choennagel and colleagues (2004)provide an important contributiontoward explaining how different fireregimes operate in western forests andthe implications for forest manage-ment. We agree that this variabilityneeds to be recognized in forest restora-tion efforts in the West,where a modelof frequent surface fire is often broadlyapplied to areas with different naturalfire egimes.However, we do not agree that thefire severity data from the 2002 Rodeo-Chediski fire in Arizona cited by Schoen-nagel and colleagues indicate that forestmanipulations reduced fire severity.There is no analysis of variance in burnseverity by treatment or setting in thedata cited (Wilmes et al.2002,displayedin figures 7 and 8 in Schoennagel et al.2004). It is not clear that the samplingwas consistent with statistical require-ments for hypothesis testing.Topogra-phy,weather,fire suppression activities,and other factors can strongly influencefire severity,yet Wilmes and colleagues(2002) do not explain how these factorsvary among sites or were controlled forin sampling.Burn severity is typically highly vari-able,and the relative differences in burnseverity by treatment are relatively smallin the data of Wilmes and colleagues(2002). If burn severity had been sam-pled consistent with statistical consid-erations,it is possible that the data mightindicate there was no treatment effect.Without adequate sampling design andstatistical analysis, it is impossible toreasonably determine what effect treat-ments had on fire severity in the Rodeo-Chediski fire.Although evaluating forest manipu-lations aimed at reducing fire severity ina broad ecological context is outside thescope of the article by Schoennagel andcolleagues (2004), that work needs tobe done. Mechanized fuel treatmentscause collateral damage to ecosystemcomponents, including soils, aquatics,and vegetation; they also have the po-tential to spread exotic plants andpathogens.The negative ecological im-pacts ofsalvage loggingNone treatmentdescribed in Wilmes and colleagues(2002)Nhave been identified in con-siderable detail (Beschta et al.2004,Lin-denmayer et al. 2004). Even if suchtreatments do reduce fire severity, theecological cost of those treatments mayoutweigh any positive effects. In mostcases,the negative effects of treatmentswill cover a substantially greater areathan that for which fire severity might bereducedNif, that is, fire should occur.The likelihood that treatments will affectwildfire severity is relatively low,becauseofthe low probability offire at a specificlocation and the transient nature ofsuchtreatments.In conclusion,we do not dispute thatfire regimes have been altered in south-western forests, nor do we necessarilydispute that forest manipulations canreduce fire severity in these systems.However,there remain major questionsregarding the likely effectiveness and thenet ecological effects ofsuch manipula-tions;these should be answered by rig-orous research before large areas offorestare reconfigured.This will require bet-ter understanding of the natural rolethat fires and fuels play in differentforests.We commend Schoennagel andcolleagues for adding to our under-standing on this front.JONATHAN J.RHODES Conservation HydrologistPlaneto Azul Hydrologic ConsultantsPO Box 15286Portland,OR 97293 DENNIS C.ODIONInstitute for Computational EarthSystems ScienceUniversity of CaliforniaSanta Barbara,CA 93106

Design of Regular Landscape Fuel Treatment Patterns for Modifying Fire Growth and Behavior

Article

May 2001
FOREST SCI

Mark A. Finney

Patterns of disconnected fuel treatment patches that overlap in the heading fire spread direction are theoretically effective in changing forward fire spread rate. The analysis presented here sought to find the unit shape and pattern for a given level of treatment that has the maximum effect on forward spread rate. This occurs when the treatment units cause the fire to spread through them at the same rate as it spreads around them. Simulations suggested that these treatment patterns reduce the spread rate or fireline intensity over much of the area burned, even outside the treatment units where the fire was forced to flank. The ideal patterns are theoretically scale independent, allowing for flexible application across heterogeneous landscapes. The topology of these patterns has implications for designing landscape-level fuel treatment patterns and for understanding spatial dynamics of fuel patterns across landscapes. FOR. SCI. 47(2):219–228.

Impacts of restoration treatments on alien plant invasion in Pinus ponderosa forests, Montana, USA

Article

Oct 2006

1. Invasion by alien plant species represents a challenge to land managers throughout the world as they attempt to restore frequent fire-adapted ecosystems following decades of fire exclusion. In ponderosa pine Pinus ponderosa forests of western North America, the response of alien species to restoration treatments has not been well documented, particularly for alien species capable of altering environmental conditions (trans -formers). Understanding alien species dynamics is critical for developing treatments that accomplish restoration goals while minimizing alien invasion. 2. We used a replicated, randomized block experiment to compare the effects of an untreated control and thin-only, burn-only and thin-burn treatments on alien and transformer understorey species at multiple spatial scales (1 m 2 , 100 m 2 and 1000 m 2). Data were collected pre-treatment and for multiple post-treatment years. We compared richness and cover of alien species and transformer species among treatments, and identified environmental variables correlated with transformer species cover. Indicator species analysis was used to identify transformer species associated with specific treatments. 3. Alien and transformer species richness and cover were significantly higher in the thin-burn than in all other treatments at all spatial scales. Thin-only and burn-only treatments showed greater alien and transformer species responses than the control at the larger 100-m 2 and 1000-m 2 scales. 4. Increased transformer cover was strongly correlated with increased tree crown scorch height and removal of overstorey trees. 5. The thin-burn treatment had four transformer species as indicators, the thin-only had one, while the burn-only and control had none. 6. Synthesis and applications . The results show that alien species, including trans -formers, respond to restoration treatments, especially the combined thin-burn treatment. Therefore monitoring for alien species invasion is an essential component of a restoration programme. Abundance of transformer species increased with increasing disturbance intensity, suggesting that less intense single-disturbance treatments (burn-only, thin-only) or incremental treatments may be preferred in some applications. Where more intense treatments are required to meet management objectives, specific strategies, such as seeding of native species, limiting grazing before and after treatment and harvesting over a protective winter snowpack, may be necessary to limit alien invasion.

Death Rides the Forest: Perceptions of Fire, Land Use, and Ecological Restoration of Western Forests

Article

Aug 2004

John Boone Kauffman

Large wild fires occurring in forests, grasslands, and chaparral in the last few years have aroused much public concern. Many have described these events as “catastrophes” that must be prevented through aggressive increases in forest thinning. Yet the real catastrophes are not the fires themselves but those land uses, in concert with fire-suppression policies that have resulted in dramatic alterations to ecosystem structure and composition. The first step in the restoration of biological diversity (forest health) of western landscapes must be to implement changes in those factors that have caused degradation or are preventing recovery. This includes changes in policies and practices that have resulted in the current state of wildland ecosystems. Restoration entails much more than simple structural modifications achieved though mechanical means. Restoration should be undertaken at landscape scales and must allow for the occurrence of dominant ecosystem processes, such as the natural fire regimes achieved through natural and/or prescribed fires at appropriate temporal and spatial scales.

Status of native fishes in the Western United States and issues for fire and fuels management

Article

Jun 2003
FOREST ECOL MANAG

Conservation of native fishes and changing patterns in wildfire and fuels are defining challenges for managers of forested landscapes in the western United States. Many species and populations of native fishes have declined in recorded history and some now occur as isolated remnants of what once were larger more complex systems. Land management activities have been viewed as one cause of this problem. Fires also can have substantial effects on streams and riparian systems and may threaten the persistence of some populations of fish, particularly those that are small and isolated. Despite that, major new efforts to actively manage fires and fuels in forests throughout the region may be perceived as a threat rather than a benefit to conservation of native fishes and their habitats. The management of terrestrial and aquatic resources has often been contentious, divided among a variety of agencies with different goals and mandates. Management of forests, for example, has generally been viewed as an impact on aquatic systems. Implementation of the management-regulatory process has reinforced a uniform approach to mitigate the threats to aquatic species and habitats that may be influenced by management activities. The problems and opportunities, however, are not the same across the landscapes of interest. Attempts to streamline the regulatory process often search for generalized solutions that may oversimplify the complexity of natural systems. Significant questions regarding the influence of fire on aquatic ecosystems, changing fire regimes, and the effects of fire-related management remain unresolved and contribute to the uncertainty. We argue that management of forests and fishes can be viewed as part of the same problem, that of conservation and restoration of the natural processes that create diverse and productive ecosystems. We suggest that progress toward more integrated management of forests and native fishes will require at least three steps: (1) better integration and development of a common conceptual foundation and ecological goals; (2) attention to landscape and ecological context; and (3) recognition of uncertainty.

The challenge of quantitative risk analysis for wildland fire

Article

Jun 2005
FOREST ECOL MANAG

Mark A. Finney

Quantitative fire risk analysis depends on characterizing and combining fire behavior probabilities and effects. Fire behavior probabilities are different from fire occurrence statistics (historic numbers or probabilities of discovered ignitions) because they depend on spatial and temporal factors controlling fire growth. That is, the likelihood of fire burning a specific area is dependent on ignitions occurring off-site and the fuels, topography, weather, and relative fire direction allowing each fire to reach that location. Research is required to compare computational short-cuts that have been proposed for approximating these fire behavior distributions. Fire effects in a risk analysis must also be evaluated on a common scale for the variety of values susceptible to wildland fire. This means that appraisals of fire impacts to human infrastructure and ecological values must be measured by the same currency so that the risk assessment yields a single expectation of fire effects. Ultimately, this will help guide planning and investment into management activities that can alter either the probabilities of damaging fire or the susceptibility to those fire behaviors.

Conceptual model for comparative ecological risk assessment of wildfire effects on fish, with and without hazardous fuel treatment

Article

Jun 2005
FOREST ECOL MANAG

Jay O ' Laughlin

Wildfire poses risks to fish and wildlife habitat, among other things. Management projects to reduce the severity of wildfire effects by implementing hazardous fuel reduction treatments also pose risks. How can land managers determine which risk is greater? Comparison of risks and benefits from fuel treatment projects to risks from severe wildfire effects is consistent with policies requiring public land managers to analyze short- and long-term environmental effects. However, formulating the problem as a comparison of temporal considerations often results in decisions to reject fuels treatment projects near imperiled species habitat, even though the adverse effects of short-term project actions may result in substantial long-term net benefits from reducing the severity of wildfire effects. Consistent with widely accepted ecological risk assessment methods, the problem is formulated in a conceptual model. Salmonid fish populations are the risk assessment endpoint, and one stressor adversely affecting them is sediment from wildfire or logging. The model compares short-term effects of implementing fuels reduction treatments to longer-term wildfire effects with and without fuel treatments, including risk reduction benefits. Used quantitatively or qualitatively, the model may contribute to sustainable resource management decisions by improving communication among stakeholders, risk managers in land and resource management agencies, and risk assessors in agencies responsible for enforcing the Endangered Species Act.

Federal Forest Fire Policy in the United States

Article

Apr 2005

Forest-fire policy of U.S. federal agencies has evolved from the use of small patrols in newly created National Parks to diverse policy initiatives and institutional arrangements that affect millions of hectares of forests. Even with large expenditures and substantial infrastructure dedicated to fire suppression, the annual area burned by wildfire has increased over the last decade. Given the current and future challenges of fire management, and based on analytical research and review of existing policies and their implications, we believe several changes and re-emphases in existing policy are warranted. Most importantly, the actual goal of fuels-management projects should be the reduction of potential fire behavior and effects, not the simple reduction of fuels. To improve safety and economic efficiency, fire-suppression policies should recognize differences in the characteristics of wildfires, and strategies should be tailored to better respond to the unique demands of each fire. Where forest fires are burning large areas, as in the western United States, reducing the trend of increased amounts of burned area may require a diversity of treatments, including prescribed burning, mechanical fuels treatment, and increased use of the Wildland Fire Use Policy. Assessment of how fire is affecting forests would be enhanced if land-management agencies reported the area burned by low-, mixed-, and high-severity fire and what proportion is outside the desired trend or range of conditions for each forest type. Congress should provide an improved budgetary process for fire and fuels management, with a larger annual federal fire-suppression budget. Additionally, reducing annual area burned will require long-term coordinated efforts by federal and state governments, with robust partnerships between land-management agencies and the public in collaborative planning and stewardship. Research and adaptive management are essential in allowing fire-hazard-reduction projects to move forward where proposed projects are met with uncertainty and mistrust. While legislative reform may be desirable, a strategy that is not entirely dependent on new legislation is needed. Building on existing programs that are consistent with a science-based strategy will enable land-management agencies to better utilize information in pursuit of the overall objective of reducing uncharacteristically severe wildfires. yes

Standand landscape-level effects of prescribed burning on two Arizona wildfires

Article

Jul 2005

Performance of fuel treatments in modifying behavior and effects of the largest wildfires has rarely been evaluated, because the necessary data on fire movement, treatment characteristics, and fire severity were not obtainable together. Here we analyzed satellite imagery and prescribed fire records from two Arizona wildfires that occurred in 2002, finding that prescribed fire treatments reduced wildfire severity and changed its progress. Prescribed burning in ponderosa pine forests 1-9 years before the Rodeo and Chediski fires reduced fire severity compared with untreated areas, despite the unprecedented 1860-km2 combined wildfire sizes and record drought. Fire severity increased with time since treatment but decreased with unit size and number of repeated prescribed burn treatments. Fire progression captured by Landsat 7 enhanced thematic mapper plus (ETM+) clearly showed the fire circumventing treatment units and protecting areas on their lee side. This evidence is consistent with model predictions that suggest wildland fire size and severity can be mitigated by strategic placement of treatments.

Helping western forests heal

Article

Dec 2000

William Covington

The prognosis is poor for US forest ecosystems.

fuel treatments, and ecological restoration RMRS-P-29 Fort Collins:USDA Forest Service Rocky Mountain Research Station Warming and earlier spring increases western U.S. forest wildfire activity

Jan 2002
259-75940

Tt Veblen
Al Westerling
Hg Hidalgo
Dr Cayan
Tw Swetnam

Veblen TT. Key issues in fire regime research for fuels management and ecological restoration. In P. N. Omi, and L. A. Joyce, eds. Proceedings of conference on fire, fuel treatments, and ecological restoration RMRS-P-29; 2002: Fort Collins:USDA Forest Service Rocky Mountain Research Station; 2003; pp. 259-75. [25] Westerling AL, Hidalgo HG, Cayan DR, Swetnam TW. Warming and earlier spring increases western U.S. forest wildfire activity. Science 2006; 313:940-3. [26] U.S. Department of Agriculture Office of Inspector General. Audit report: Implementation of the Healthy Forests Initiative USDA/OIG-A/08601-6-AT. Washington: USDA Office of Inspector General; 2006. [27]

Amer Fish Soc Federal forest-fire policy in the United States Long-term sedimentation effects of different patterns of timber harvesting

Jan 1991
532-574

Tf Waters
Sl Stephens
Lw Ruth
Rr Ziemer
J Lewis
Te Lisle
Rm Rice

Waters TF. Sediment in streams: sources, biological effects, and control. Bethesda: Amer Fish Soc; 1995 [18] Stephens SL, Ruth LW. Federal forest-fire policy in the United States. Ecol Appl 2005; 15: 532-42. [19] Ziemer RR, Lewis J, Lisle TE, Rice RM. Long-term sedimentation effects of different patterns of timber harvesting. In: Proceedings of the symposium on sediment and stream water quality in a changing environment: Trends and explanation Inter Assoc Hydrol Sci Publ no. 203; 1991: Wallingford, UK: Inter Assoc Hydrol Sci; 1991; pp. 143-50. [20]

The effects of postfire salvage logging on aquatic ecosystems in the American West Hydrologic and erosional responses of a granitic watershed to helicopter logging and broadcast burning

Jan 1995
1029-33777

Jr Karr
Jj Rhodes
Gw Minshall

Karr JR, Rhodes JJ, Minshall GW, et al. The effects of postfire salvage logging on aquatic ecosystems in the American West. Bio- Science 2004; 54: 1029-33. [15] Megahan, WF, King JG, Seyedbagheri KA. Hydrologic and erosional responses of a granitic watershed to helicopter logging and broadcast burning. For Science 1995; 41:777-95. [16]

The role of fuel breaks in the invasion of nonnative plants, US Geological Survey scientific investigations report 2006-5185. Reston: US Geol Survey [11] Gresswell RE. Fire and aquatic ecosystems in forested biomes of North America

Jan 1999
193-221

Ke Merriam
Je Keeley
Jl Beyers

Merriam, KE, Keeley JE, Beyers JL. The role of fuel breaks in the invasion of nonnative plants, US Geological Survey scientific investigations report 2006-5185. Reston: US Geol Survey; 2007. [11] Gresswell RE. Fire and aquatic ecosystems in forested biomes of North America. Trans Amer Fish Soc 1999; 128: 193-221. [12]

Helping western forests heal: the prognosis is poor for US forest ecosystems Fire severity in the Sierra Nevada Revisited: Conclusions robust to further analysis Fuel accumulation rates after prescribed fires in Yosemite National Park Managing fire-prone forests in the western United States

Jan 1987
135-141

Ww Covington
Dc Odion
Ct Hanson
Jw Van Wagtendonk
Ca Sydoriak

Covington WW. Helping western forests heal: the prognosis is poor for US forest ecosystems. Nature 2000; 408: 135-6. [38] Odion DC, Hanson CT. Fire severity in the Sierra Nevada Revisited: Conclusions robust to further analysis. Ecosystems In Press. [39] van Wagtendonk JW, Sydoriak CA. Fuel accumulation rates after prescribed fires in Yosemite National Park. In: Proceedings of 9 th conference on fire & forest meteorology; 1987: San Diego; Am Meteor Soc 1987; pp. 101-5. [40] Noss, RF, Franklin JF, Baker WL, Schoennagel T, Moyle, PB. Managing fire-prone forests in the western United States. Front Ecol Environ 2006; 4: 481-7. [41]

Fire Probability, Fuel Treatment Effectiveness and Ecological Tradeoffs in Western U.S. Public Forests

Abstract

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