Abstract  The purpose of this investigation was to examine the influence of residents’ attachment to their homes and community on their willingness to adopt Firewise recommendations. Our sample was drawn from a population residing in the wildland–urban interface where the threat of wildfire is acute. The Firewise recommendations concerned 13 activities affecting home design, construction and maintenance, landscaping, and community engagement. Consistent with the tenets offered by the elaboration likelihood model of persuasion and empirical evidence stemming from the place and community attachment literatures, we hypothesized that those most attached to their homes and community would be most inclined to adopt Firewise recommendations to protect these settings. For the most part, our findings were consistent with this hypothesis. We observed that the dimensions of home attachment were most strongly predictive of activities centered on and around the home, whereas community attachment was more strongly predictive of community-based activities.

Abstract  This study attempts to provide relative magnitudes of average and marginal costs of off-site sediment-related costs in Oregon's Willamette Valley. Water treatment; road, river channel, and dam maintenance; and hydroelectric generation are examined.Road maintenance and water treatment are nonnegligible average cost items. These costs should not be interpreted as justification for erosion control as marginal cost estimates for water treatment indicate that controls on the margin would yield roughly one-third the average cost.

Abstract  Two traditional economic efficiency criteria, minimization of cost plus net value change versus profit maximization, are compared in terms of the insights provided into fire management decisions. The historic rationale for favoring minimization over maximization is examined and questioned. Advantages of formulating the problem in terms of profit maximization include explicit attention to production relations obscured by previous graphical representations of the minimization criterion. The maximization formulation also facilitates more explicit treatment of revenue and objective functions. For illustration, we show the correspondence between fire management decisions and the firm with two inputs (presuppression, suppression) and two outputs (reductions in fire intensity and area burned).

Abstract  Research has suggested that excessive risk aversion is a key driver of rising federal suppression costs. To formally understand how alternative risk attitudes of contracted incident managers can affect a public fire management organization's demand for fire management effort, a two-stage sequential game with complete information is presented. Qualitative expressions of the relevant comparative statics are derived and Monte Carlo simulations are constructed from the parameterized game to quantify these relationships. The simulation exercise reveals that risk aversion and a low tolerance for downside risk can have the similar effect of increasing the relative share of agency expenditures devoted to wildfire suppression. This theoretical analysis exposes the potential for multiple types of risk attitudes to influence an incident commander's demand for suppression effort. Consequently, these determinants of suppression demand also influence the organization's overall allocation of fire management budgets, suppression's expenditure share, and the overall agency exposure to downside risk.

Abstract  (m) Prescribed fire is any fire intentionally ignited by management actions in accordance with applicable laws, policies, and regulations to meet specific land or resource management objectives.

Abstract  There is an urgent and immediate need to address the excessive cost of large fires. Here, we studied large wildland fire suppression expenditures by the US Department of Agriculture Forest Service. Among 16 potential nonmanagerial factors, which represented fire size and shape, private properties, public land attributes, forest and fuel conditions, and geographic settings, we found only fire size and private land had a strong effect on suppression expenditures. When both were accounted for, all the other variables had no significant effect. A parsimonious model to predict suppression expenditures was suggested, in which fire size and private land explained 58% of variation in expenditures. Other things being equal, suppression expenditures monotonically increased with fire size. For the average fire size, expenditures first increased with the percentage of private land within burned area, but as the percentage exceeded 20%, expenditures slowly declined until they stabilised when private land reached 50% of burned area. The results suggested that efforts to contain federal suppression expenditures need to focus on the highly complex, politically sensitive topic of wildfires on private land.

Abstract  This state-of-knowledge review about the effects of fire on soils and water can assist land and fire managers with information on the physical, chemical, and biological effects of fire needed to successfully conduct ecosystem management, and effectively inform others about the role and impacts of wildland fire. Chapter topics include the soil resource, soil physical properties and fire, soil chemistry effects, soil biology responses, the hydrologic cycle and water resources, water quality, aquatic biology, fire effects on wetland and riparian systems, fire effects models, and watershed rehabilitation.

Abstract  This paper provides a detailed review of the chemical changes that occur in soil during a fire, the pathways by which nutrients are transferred from soil to surface-water bodies following a fire, and the temporal and spatial effects of fires on the concentration of nutrients in surface-water bodies during and following a fire that have been reported in the scientific literature. Thirty-nine papers from the scientific literature that represent studies that (1) were done in a variety of environments (savannas, grasslands, temperate forests, alpine forests, and so forth); (2) had a range of sampling frequency and duration, such as during and immediately following a fire (from the start of fire to 1 year later), short-term sampling (from end of fire to 3 years later), and long term-sampling (sampling for greater than 3 years following a fire); and (3) incorporated watersheds with various burn intensities, severities, and histories were reviewed and summarized. The review of the scientific literature has revealed that measurable effects of fires on streamwater quality are most likely to occur if the fire was severe enough to burn large amounts of organic matter, if windy conditions were present during the fire, if heavy rain occurred following the fire, and if the fire occurred in a watershed with steep slopes and soils with little cation-exchange capacity. Measurable effects of fires on lake- and reservoirwater quality are most likely to occur if, in addition to the factors listed for streams, the lake or reservoir is oligotrophic or mesotrophic and the residence time of water in the lake or reservoir is short relative to the length of time elevated concentrations of nutrients occur in runoff. Knowledge of whether a lake or reservoir is nitrogen or phosphorus limited is important because eutrophication of nitrogen-limited lakes may occur following a fire due to increasing nitrogen:phosphorus ratios caused by prolonged increases of nitrogen concentrations, especially nitrate.

Abstract  We use a travel cost model to test the effects of wild and prescribed fire on visitation by hikers and mountain bikers in New Mexico. Our results indicate that net benefits for mountain bikers is $150 per trip and that they take an average of 6.2 trips per year. Hikers take 2.8 trips per year with individual net benefits per trip of $130. Both hikers' and mountain bikers' demand functions react adversely to prescribed burning. Net benefits for both groups fall as areas recover from prescribed burns. Because both visitation and annual recreation benefits decrease to these two types of visitors, this gives rise to multiple use costs associated with prescribed burning. With respect to wildfire, hikers and mountain bikers both exhibit decreased visitation as areas recover from wildfires, however, only hikers indicate an increase in per trip net benefits. Bikers' demand effectively drops to zero. These results differ from previous findings in the literature and have implications for efficient implementation of the National Fire Plan and whether prescribed burning is a cost effective tool for multiple use management of National Forests. Specifically, that fire and recreation managers cannot expect recreation users to react similarly to fire across recreation activities, or different geographic regions. What is cost effective in one region may not be so in another.

Abstract  Wildfire can influence a variety of stream ecosystem properties. We studied stream temperatures in relation to wildfire in small streams in the Boise River Basin, located in central Idaho, USA. To examine the spatio-temporal aspects of temperature in relation to wildfire, we employed three approaches: a pre–post fire comparison of temperatures between two sites (one from a burned stream and one unburned) over 13 years, a short-term (3 year) pre–post fire comparison of a burned and unburned stream with spatially extensive data, and a short-term (1 year) comparative study of spatial variability in temperatures using a “space for time” substitutive design across 90 sites in nine streams (retrospective comparative study). The latter design included streams with a history of stand-replacing wildfire and streams with severe post-fire reorganization of channels due to debris flows and flooding. Results from these three studies indicated that summer maximum water temperatures can remain significantly elevated for at least a decade following wildfire, particularly in streams with severe channel reorganization. In the retrospective comparative study we investigated occurrence of native rainbow trout (Oncorhynchus mykiss) and tailed frog larvae (Ascaphus montanus) in relation to maximum stream temperatures during summer. Both occurred in nearly every site sampled, but tailed frog larvae were found in much warmer water than previously reported in the field (26.6°C maximum summer temperature). Our results show that physical stream habitats can remain altered (for example, increased temperature) for many years following wildfire, but that native aquatic vertebrates can be resilient. In a management context, this suggests wildfire may be less of a threat to native species than human influences that alter the capacity of stream-living vertebrates to persist in the face of natural disturbance.

Abstract  Following fire, changes in streamflow and bank stability in burned watersheds can mobilize coarse woody debris. In 1990 and 1991, I measured characteristics of coarse woody debris and standing riparian trees and snags in Jones Creek, a watershed burned in 1988, and in Crow Creek, an unburned watershed. The mean diameter of riparian trees along Jones Creek was less than that of trees along Crow Creek, but the coarse woody debris in Jones Creek was greater in mean diameter. Tagged debris in Jones Creek was three times as likely to move, and moved over four times as far as such debris in Crow Creek. In Jones Creek, the probability of movement was higher for tagged pieces that were in contact with the stream surface. Larger pieces tended to be more stable in both streams. It appears that increased flows and decreased bank stability following fire increased the transport of coarse woody debris in the burned watershed. Overall, debris transport in Rocky Mountain streams may be of greater significance than previously recognized.

Abstract  This analysis examines the dynamic path of recreational values following a forest fire in three different states in the intermountain western United States. The travel cost demand analysis found that annual recreation values after a fire follow a highly nonlinear intertemporal path. The path is S-shaped, providing a range of benefits and losses in the years following a fire. While the results discourage the use of a single value throughout the Intermountain West, they do provide a range of likely values that public land managers can apply to fire-affected areas in their jurisdictions.

Abstract  Forest fires are increasing across the American West due to climate warming and fire suppression. Accelerated snow melt occurs in burned forests due to increased light transmission through the canopy and decreased snow albedo from deposition of light-absorbing impurities. Using satellite observations, we document up to an annual 9% growth in western forests burned since 1984, and 5 day earlier snow disappearance persisting for >10 years following fire. Here, we show that black carbon and burned woody debris darkens the snowpack and lowers snow albedo for 15 winters following fire, using measurements of snow collected from seven forested sites that burned between 2002 and 2016. We estimate a 372 to 443% increase in solar energy absorbed by snowpacks occurred beneath charred forests over the past two decades, with enhanced post-fire radiative forcing in 2018 causing earlier melt and snow disappearance in >11% of forests in the western seasonal snow zone.

Abstract  This study investigates the impact of wildfire on the climate of Southern Africa. Moderate resolution imaging spectroradiometer derived burned area fraction data was implemented in a set of simulations to assess primarily the role of wildfire-induced surface changes on monthly precipitation. Two post-fire scenarios are examined namely non-recovering and recovering vegetation scenarios. In the former, burned vegetation fraction remains burned until the end of the simulations, whereas in the latter it is allowed to regrow following a recovery period. Control simulations revealed that the model can dependably capture the monthly precipitation and surface temperature averages in Southern Africa thus providing a reasonable basis against which to assess the impacts of wildfire. In general, both wildfire scenarios have a negative impact on springtime precipitation. September and October were the only months with statistically significant precipitation changes. During these months, precipitation in the region decreases by approximately 13 and 9% in the non-recovering vegetation scenario, and by about 10 and 6% in the recovering vegetation wildfire scenario, respectively. The primary cause of precipitation deficit is the decrease in evapotranspiration resulting from a reduction in surface net radiation. Areas impacted by the precipitation reduction includes the Luanda, Kinshasa, and Brazzaville metropolitan areas, The Angolan Highlands, which are the source of the Okavango Rive, and the Okavango Delta region. This study suggests that a probable intensification in wildfire frequency and extent resulting from projected population increase and global warming in Southern Africa could potentially exacerbate the impacts of wildfires in the region’s seasonal precipitation.

Abstract  1 The effects of wildfire ash on ectomycorrhizal (EM) associations were investigated by sampling bishop pine (Pinus muricata, D. Don) seedlings from control and ash‐removed plots 1.5 years after a severe fire in a northern Californian P. muricata forest. The below‐ground community composition of EM at the site was characterized using molecular techniques (PCR‐RFLP and nucleotide sequencing). 2 A total of 30 fungal taxa were observed, many of which differed in their distribution between treatment and control seedlings. However, most of the taxa that were distinctive to either treatment or control seedlings occurred only once across the site, precluding statistical detection of potential ash effects on EM community composition. There were no significant effects of ash removal on plot‐level mycorrhizal community richness or diversity, and there were no distinct treatment‐related clusters in a principal components analysis. 3 Analysis of the combined data indicated that numbers of fungal taxa per seedling, numbers of successive root depth increments colonized by the same taxon, and distances to neighbouring seedlings colonized by the same taxon, were randomly distributed across the site for the majority of mycorrhizal fungi. These distributional patterns suggest that the post‐fire mycorrhizal community structure on P. muricata arose primarily from successful colonization by randomly distributed point‐source fungal inocula within the upper mineral soil layer of the forest floor. 4 By comparison with pre‐fire studies from similar P. muricata sites nearby, our data indicate that severe wildfire disturbance resulted in marked changes in mycorrhizal community composition, and a sharp increase in the relative biomass of ascomycetous fungi.

Abstract  Purpose of Review We reviewed recent peer-reviewed literature on three categories of individual- and household-level interventions against air pollution: air purifiers, facemasks, and behavior change. Recent Findings High-efficiency particulate air/arresting (HEPA) filter air purifier use over days to weeks can substantially reduce fine particulate matter (PM2.5) concentrations indoors and improve subclinical cardiopulmonary health. Modeling studies suggest that the population-level benefits of HEPA filter air purification would often exceed costs. Well-fitting N95 and equivalent respirators can reduce PM2.5 exposure, with several randomized crossover studies also reporting improvements in subclinical cardiovascular health. The health benefits of other types of face coverings have not been tested and their effectiveness in reducing exposure is highly variable, depends largely on fit, and is unrelated to cost. Behavior modifications may reduce exposure, but there has been little research on health impacts. Summary There is now substantial evidence that HEPA filter air purifiers reduce indoor PM2.5 concentrations and improve subclinical health indicators. As a result, their use is being recommended by a growing number of government and public health organizations. Several studies have also reported subclinical cardiovascular health benefits from well-fitting respirators, while evidence of health benefits from other types of facemasks and behavior changes remains very limited. In situations when emissions cannot be controlled at the source, such as during forest fires, individual- or household-level interventions may be the primary option. In most cases, however, such interventions should be supplemental to emission reduction efforts that benefit entire communities.

Abstract  Thousands of hectares of wildlands are burned annually in the western United States. The composition and mineralogy of wood-ash produced by severe burning, and the changes in pH of soils underlying the ash, were examined at five sites in Califor-nia. Soil pH increased by as much as 3 pH units (to pH 10.5) immediately after burn-ing compared with unburned soil. Approx-imately 1 to 2% of each burn area was affected to a maximum observed depth of 20 cm. The major component of fresh, white wood-ash is calcite, while K and Na carbonates are present in minor amounts. The initial very high pH values of wood-ash and surface soil are caused by K and Na oxides, hydroxides, and carbonates. These compounds are very soluble and do not persist through the wet season. The calcite is much less soluble and was present in soils 3 years after burning, maintaining moderately alkaline pH in surface soils that are normally neutral to strongly acid.

Abstract  Laboratory studies indicate that percolation of water through accretions of plant ash will markedly increase the pH of solutions entering the underlying soil. Ash derived from graminaceous straws raised the pH of an aqueous suspension (1 g ash: 500 ml H2O) to 10.6, compared to 9.3 for a saturated solution of CaCO3. However, on a weight basis these ashes possess only approximately 5–15% of the alkalising power of CaCO3 in terms of their ability to neutralise acid or elevate soil pH. The effect of ash on soil pH, and pH dependent soil properties, is determined by the amount and composition of the ash deposited and on the buffering capacity of the soil. High field rates (2480–6750 kg ha−1) of ash added to a podzolic soil increased the pH of the soil solution by up to 3 units. A pH rise of 1 unit is sufficient to increase the solubility of native soil organic carbon (O.C.) in water (i.e. mobilize readily metabolizable microbial substrate) and stimulate respiration rate. In more strongly buffered krasnozem soil, maximum rise in pH of the soil solution did not exceed 0.7 unit. However, even such small pH shifts significantly reduced the solubility of soil O.C. in water; probably by changing the character (and hence solubility) of organo-mineral chelation complexes. High rates of ash application also slightly decreased respiration rate in this soil type. The application of neutralized ash, which added metal ions to the soil solution, had a similar but smaller effect to unneutralized ash on the solubility of soil O.C. in podzolic soil, but little effect in krasnozem soil.

Abstract  Smoke or heat from fire can act as a cue that affects seed germination. We examined germination responses of 10 plant species (six forbs, two shrubs, two grasses) native to the southern High Plains in the United States, to smoke, heat, and their interaction in a laboratory experiment. Smoke treatments were applied by soaking seeds in 1∶5, 1∶10, or 1∶100 (v/v) Regen 2000® smoke solution for 20 h. Heat treatments were applied by placing seeds in an oven at 50°C or 80°C for 5 min. Nine species responded to smoke, heat, or both. Results showed that smoke can enhance, inhibit, or not affect seed germination. Germination capacities of Gutierrezia sarothrae (Pursh) Britton & Rusby and Astragalus crassicarpus Nutt. were promoted by 1∶5 and 1∶100 dilutions of smoke water, respectively; Coreopsis tinctoria Nutt., G. sarothrae, Salvia reflexa Hornem., Digitaria ciliaris (Retz.) Koeler, and Panicum virgatum L. were inhibited by high and/or moderate concentrations of smoke water either in germination percentage or in mean germination time. Germination percentage of Solanum elaeagnifolium Cav. increased following an 80°C heat treatment. Interaction effects between smoke and heat on germination also were detected. Smoke and heat treatments might be useful as management tools for promoting or suppressing specific target species of shortgrass prairie communities in future habitat management.

Abstract  The paper examines, by climax conifer series, historical and current roles of many important pathogens and insects of interior Northwest coniferious forests and their unique responses to changing successional conditions resulting from management. Future research on forest pathogens and insects should address three primary subject areas: insect and pathogen population dynamics in managed and unmanaged forests; ecological roles and effects of native and introduced pathogens and insects; and effects of natural disturbances and management practices on native insects, pathogens, and their natural enemies.

Abstract  We proposed and developed a multi-scale analysis of the relationships between climate and topography and spatio-temporal patterns in historical fire regimes in the inland Pacific Northwest, using existing fire history data from six watersheds on the Okanogan-Wenatchee and Colville National Forests. We investigated current year, lagged, and low frequency relationships between composite fire histories and Palmer Drought Severity Index (PDSI), Pacific Decadal Oscillation (PDO), and the Southern Oscillation Index (SOI) using superposed epoch analysis and cross-spectral analysis. We identified smaller scale controls on fire exerted by fuel limitations by comparing patterns of fire hazard over time on simulated landscapes without controls to landscapes in the six watersheds. We used spatial autocorrelation, geostatistics, and multivariate methods to quantify the spatial structures of fire regimes and how they depended on local topography. We documented clear differences in fire regimes between the historical period (ca. 1650-1900) and the period after initiation of fire suppression in the region (ca.1900). We developed a unique geo-spatial database that takes advantage of both the spatially explicit nature of the fire-history data and new paradigms in geographic information science.