Fuel Reduction Treatments Research Articles

Influence of fuel-reduction forest thinning on growth of an arboreal forage lichen

Significant differences in microclimate have been found within crowns of dispersed vs. clumped leave trees resulting from fuels reduction treatments in Sierra Nevada mixed-conifer forest. The question remained whether these differences in abiotic conditions might be biologically significant to arboreal epiphyte communities. The objective of our experiment was to assess growth of transplants of a lichen epiphyte, Bryoria fremontii, in relation to differences in within-crown vapor pressure deficits (VPD) among no-thin control, and understory (U-thin) and overstory (O-thin) fuels reduction prescriptions. Transplant annual relative growth ranged from 6.2–11.6%. We expected Bryoria growth would be greatest in trees in intact forest of the control and less in the O-thin after treatment, but there was no statistical difference. The control had the highest VPDs and the least growth before thinning. Bryoria grew best, both before and after thinning, in trees nearest streams and in the U-thin where VPDs were lowest. Classification and regression tree analysis revealed a positive correlation between Bryoria growth and greater basal area (BA) surrounding study trees before thinning, and lower VPDs after thinning. Topographic positions of the study plots confounded within-crown VPDs among treatments and therefore on Bryoria growth. The U-thin plot had a lower topographic position that was more affected by a moisture-influenced riparian microclimate than the more upland control and O-thin plots. However, results consistently suggest that greater BA surrounding trees buffers their within-crown microclimate and favors Bryoria growth. Fuels treatments that thin from below and leave large, live trees in a clumped pattern may foster Bryoria, providing an important food source for the northern flying squirrel and associated arboreal food webs. Stand reconstructions have demonstrated an historical precedent for such a forest spatial pattern.

Using stochastic simulation to evaluate competing risks of wildfires and fuels management on an isolated forest carnivore

Natural resource managers are often challenged with balancing requirements to maintain wildlife populations and to reduce risks of catastrophic or dangerous wildfires. This challenge is exemplified in the Sierra Nevada of California, where proposals to thin vegetation to reduce wildfire risks have been highly controversial, in part because vegetation treatments could adversely affect an imperiled population of the fisher (Martes pennanti) located in the southern Sierra Nevada. The fisher is an uncommon forest carnivore associated with the types of dense, structurally complex forests often targeted for fuel reduction treatments. Vegetation thinning and removal of dead-wood structures would reduce fisher habitat value and remove essential habitat elements used by fishers for resting and denning. However, crown-replacing wildfires also threaten the population’s habitat, potentially over much broader areas than the treatments intended to reduce wildfire risks. To investigate the potential relative risks of wildfires and fuels treatments on this isolated fisher population, we coupled three spatial models to simulate the stochastic and interacting effects of wildfires and fuels management on fisher habitat and population size: a spatially dynamic forest succession and disturbance model, a fisher habitat model, and a fisher metapopulation model, which assumed that fisher fecundity and survivorship correlate with habitat quality. We systematically varied fuel treatment rate, treatment intensity, and fire regime, and assessed their relative effects on the modeled fisher population over 60 years. After estimating the number of adult female fishers remaining at the end of each simulation scenario, we compared the immediate negative effects of fuel treatments to the longer-term positive effect of fuel treatment (via reduction of fire hazard) using structural equation modeling. Our simulations suggest that the direct, negative effects of fuel treatments on fisher population size are generally smaller than the indirect, positive effects of fuel treatments, because fuels treatments reduced the probability of large wildfires that can damage and fragment habitat over larger areas. The benefits of fuel treatments varied by elevation and treatment location with the highest net benefits to fisher found at higher elevations and within higher quality fisher habitat. Simulated fire regime also had a large effect with the largest net benefit of fuel treatments occurring when a more severe fire regime was simulated. However, there was large uncertainty in our projections due to stochastic spatial and temporal wildfires dynamic and fisher population dynamics. Our results demonstrate the difficulty of projecting future populations in systems characterized by large, infrequent, stochastic disturbances. Nevertheless, these coupled models offer a useful decision-support system for evaluating the relative effects of alternative management scenarios; and uncertainties can be reduced as additional data accumulate to refine and validate the models.

Harvesting forest biomass for energy – An alternative to conventional fuel treatments: Trials in the Superior National Forest, USA

Abstract The goal of this article is to address the question: can the production and sale of biomass for energy help reduce the costs of conventional mechanical pile and burn forest fuel treatments? To address this question, this study analyzes data from six forest fuel reduction treatment units that combined biomass-harvesting trials in the Superior National Forest located in the state of Minnesota, USA. Machine operating and ownership costs are assessed. Costs for conventional mechanical treatment costs (pile and burn) are compared with those for a biomass-harvesting option (harvesting and delivery costs less income from the sale of recovered biomass for energy or pulp). In study trials, conventional treatment costs were found to be less than the biomass energy option costs, indicating that the conventional treatment is a cheaper option. A sensitivity analysis of different transport distance and operating conditions scenarios is carried out. Findings show that under certain operational conditions these operations could be cost effective. Conditions determining cost effectiveness are site specific and depend on-site conditions, harvesting prescriptions, biomass stocking, forwarding distance, distance to end users, equipment hauling costs, the number of operations using the same machine, the operator’s skill, and truck payload.

Effects of Fuel Reduction Treatments on Incidence of Phytophthora Species in Soil of a Southern Appalachian Mountain Forest.

The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic-causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.

Reducing Hazardous Fuels on Nonindustrial Private Forests: Factors Influencing Landowner Decisions

Abstract In mixed-ownership landscapes, fuels conditions on private lands have implications for fire risk on public lands and vice versa. The success of efforts to mitigate fire risk depends on the extent, efficacy, and coordination of treatments on nearby ownerships. Understanding factors in forest owners' decisions to address the risk of wildland fire is therefore important. This research uses logistic regression to analyze mail survey data and identify factors in forest owners' decisions to reduce hazardous fuels in the ponderosa pine (Pinus ponderosa) ecosystem on the east side of Oregon. Results suggest that owners who live on or near their land and are aware of wider landscape conditions may be important partners in fire risk mitigation and forest restoration. Results also suggest that incentives, including markets for wood products (e.g., logs and biomass) that come from fuels reduction treatments, are important for harnessing owners' potential to mitigate fire risk.

Predicting post-fire hillslope erosion in forest lands of the western United States

Many forests and their associated water resources are at increasing risk from large and severe wildfires due to high fuel accumulations and climate change. Extensive fuel treatments are being proposed, but it is not clear where such treatments should be focussed. The goals of this project were to: (1) predict potential post-fire erosion rates for forests and shrublands in the western United States to help prioritise fuel treatments; and (2) assess model sensitivity and accuracy. Post-fire ground cover was predicted using historical fire weather data and the First Order Fire Effects Model. Parameter files from the Disturbed Water Erosion Prediction Project (WEPP) were combined with GeoWEPP to predict post-fire erosion at the hillslope scale. Predicted median annual erosion rates were 0.1–2 Mg ha–1 year–1 for most of the intermountain west, ~10–40 Mg ha–1 year–1 for wetter areas along the Pacific Coast and up to 100 Mg ha–1 year–1 for north-western California. Sensitivity analyses showed the predicted erosion rates were predominantly controlled by the amount of precipitation rather than surface cover. The limited validation dataset showed a reasonable correlation between predicted and measured erosion rates (R2 = 0.61), although predictions were much less than measured values. Our results demonstrate the feasibility of predicting post-fire erosion rates on a large scale. The validation and sensitivity analysis indicated that the predictions are most useful for prioritising fuel reduction treatments on a local rather than interregional scale, and they also helped identify model improvements and research needs.

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Abstract. Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon pools to account for stochastic wildfire occurrence. The study area was a 68 474 ha watershed located on the Fremont-Winema National Forest in southeastern Oregon, USA. Fuel reduction treatments were simulated on 10% of the watershed (19% of federal forestland). We simulated 30 000 wildfires with random ignition locations under both treated and untreated landscapes to estimate the change in burn probability by flame length class resulting from the treatments. Carbon loss functions were then calculated with the Forest Vegetation Simulator for each stand in the study area to quantify change in carbon as a function of flame length. We then calculated the expected change in carbon from a random ignition and wildfire as the sum of the product of the carbon loss and the burn probabilities by flame length class. The expected carbon difference between the non-treatment and treatment scenarios was then calculated to quantify the effect of fuel treatments. Overall, the results show that the carbon loss from implementing fuel reduction treatments exceeded the expected carbon benefit associated with lowered burn probabilities and reduced fire severity on the treated landscape. Thus, fuel management activities resulted in an expected net loss of carbon immediately after treatment. However, the findings represent a point in time estimate (wildfire immediately after treatments), and a temporal analysis with a probabilistic framework used here is needed to model carbon dynamics over the life cycle of the fuel treatments. Of particular importance is the long-term balance between emissions from the decay of dead trees killed by fire and carbon sequestration by forest regeneration following wildfire.

Effects of Fuel Reduction Treatments on Avian Nest Density in the Upper Piedmont of South Carolina

The Fire and Fire Surrogate Study is a national study installed at 13 sites across the United States. One goal of the southeastern Piedmont FFS installation was to assess the effects of fuel reduction treatments such as prescribed burning and thinning on avian nest density. Nest searching and monitoring took place within twelve 10-hectare study plots during the breeding seasons of 2003 and 2004. A total of 82 nests representing 23 species were discovered and monitored. Seventy-two percent of those nests were successful in fledging young and 28% failed. Higher quantities of herbaceous material, shrubs, and small diameter trees provided more nesting substrate in Thin/Burn and Burn plots. This study suggests that prescribed burning and a combination of prescribed burning and thinning may be beneficial for Southern Piedmont bird communities, but our conclusions must be considered in light of the small sample sizes of nests. Increasing the area of upland Piedmont forest receiving prescribed burning and thinning treatments could possibly benefit early successional species that are presently experiencing population declines across the United States.

Effects of fuel reduction on bird density and reproductive success in riparian areas of mixed-conifer forest in southwest Oregon

Studies in southwest Oregon suggest that riparian areas within mixed-conifer forests historically burned with frequencies and intensities similar to upland areas and that fire played an important role in maintaining both of these ecosystems. Currently, most fuel reduction projects do not include riparian, due to the perception that these riparian areas are negatively affected by anthropogenic disturbance. However, there is very little information on the ecological consequences of including riparian areas in fuel reduction projects. We compared the effects of non-commercial thin and handpile treatments followed by prescribed burns in riparian areas of intermittent and perennial streams that were treated to the streamside (unbuffered), to the typical prescription in which sites were treated only in the adjacent upland (buffered). Unbuffered fuel reduction treatments have the potential to affect bird density and reproductive success differently than buffered treatments by altering (1) available nest habitat, (2) predator and nest parasite abundance, and (3) food availability in riparian areas. This study assessed whether unbuffered fuel reduction treatments yielded similar bird response as buffered treatments by quantifying differences in density and reproductive success of five bird species, vegetation structure, the frequency of occurrence of predators and a nest parasite, and arthropod biomass. Density was greater for the shrub and tree-nesting Pacific-slope Flycatcher in buffered streams post treatment. Reproductive success showed a minimal, near-term effect for the shrub-nesting Black-headed Grosbeak. For potential causal factors, we found differences between buffered and unbuffered streams only for available nest habitat in the upper-ground strata and frequency of occurrence of raptors. Overall, results suggest that fuel reduction in riparian areas as compared with typical upland treatments with buffers had a small effect on bird density and a near-term effect on reproductive success. Additional study of fuel reduction in riparian areas is warranted because of its effectiveness in reducing the risk of unnaturally severe wildfire and, correspondingly, the potential benefit to bird communities over the long-term.

Interactive effects of historical logging and fire exclusion on ponderosa pine forest structure in the northern Rockies

Increased forest density resulting from decades of fire exclusion is often perceived as the leading cause of historically aberrant, severe, contemporary wildfires and insect outbreaks documented in some fire-prone forests of the western United States. Based on this notion, current U.S. forest policy directs managers to reduce stand density and restore historical conditions in fire-excluded forests to help minimize high-severity disturbances. Historical logging, however, has also caused widespread change in forest vegetation conditions, but its long-term effects on vegetation structure and composition have never been adequately quantified. We document that fire-excluded ponderosa pine forests of the northern Rocky Mountains logged prior to 1960 have much higher average stand density, greater homogeneity of stand structure, more standing dead trees and increased abundance of fire-intolerant trees than paired fire-excluded, unlogged counterparts. Notably, the magnitude of the interactive effect of fire exclusion and historical logging substantially exceeds the effects of fire exclusion alone. These differences suggest that historically logged sites are more prone to severe wildfires and insect outbreaks than unlogged, fire-excluded forests and should be considered a high priority for fuels reduction treatments. Furthermore, we propose that ponderosa pine forests with these distinct management histories likely require distinct restoration approaches. We also highlight potential long-term risks of mechanical stand manipulation in unlogged forests and emphasize the need for a long-term view of fuels management.

Nesting Ecology of Yellow Warblers (Dendroica petechia) in Montane Chaparral Habitat in the Northern Sierra Nevada

The Yellow Warbler (Dendroica petechia) is considered a riparian specialist in much of western North America, but in California it also breeds in a second habitat type: montane chaparral of the Sierra Nevada and southern Cascades. We monitored Yellow Warbler nests in montane chaparral and assessed their poorly known nesting ecology in this habitat. We also conducted point counts in upland habitat throughout the region. We determined habitat associations for Yellow Warblers based on nest site and point-count vegetation data; nests were predominantly in bush chinquapin (Chrysolepis sempervirens) and greenleaf manzanita (Arctostaphylos patula), and point-count abundance was most strongly associated with high overall shrub cover. The importance of montane chaparral for a number of shrub-dependent Sierran birds is well documented, yet the chaparral is threatened by various practices including fire suppression, closed-canopy-focused forest management, and understory fuels-reduction treatments. Although Yellow Warblers are far more abundant in wet mountain meadow riparian habitat in the region, we recommend that management of montane chaparral habitat consider this species and the requirements of other shrub-nesting birds.

Dry coniferous forest restoration and understory plant diversity: The importance of community heterogeneity and the scale of observation

Maintaining understory plant species diversity is an important management goal as forest restoration and fuel reduction treatments are applied extensively to dry coniferous forests of western North America. However, understory diversity is a function of both local species richness (number of species in a sample unit) and community heterogeneity (beta diversity) at multiple spatial scales, while studies of restoration treatment effects often only examine local species richness at one or two spatial scales. We studied experimental thinning and prescribed fire treatment effects on understory plant species richness and community heterogeneity at three spatial scales using additive diversity partitioning. We also evaluated treatment effects on understory plant species colonization and extirpation at two spatial scales. There was no evidence that active restoration treatments reduced species richness or increased local extirpation of species. Restoration treatments significantly increased herbaceous species richness at the treatment-unit level primarily by increasing community heterogeneity among sampling points within the units. The combination of thinning and burning produced the greatest increase in community heterogeneity, and increased colonization by species that were not sampled prior to treatment. These results suggest that restoration treatments designed primarily to reduce fire hazard and promote sustainable conditions in these fire-adapted ecosystems can also increase community heterogeneity and facilitate colonization by new understory species without significant local extirpation of extant species.

Response of Reptiles and Amphibians to Repeated Fuel Reduction Treatments

Recent use of prescribed fire and fire surrogates to reduce fuel hazards has spurred interest in their effects on wildlife. Studies of fire in the southern Appalachian Mountains (USA) have documented few effects on reptiles and amphibians. However, these studies were conducted after only one fire and for only a short time (1–3 yr) after the fire. From mid-May to mid-August 2006 and 2007, we used drift fences with pitfall and funnel traps to capture reptiles and amphibians in a control and 3 replicated fuel-reduction treatments: 1) twice-burned (2003 and 2006), 2) mechanical understory cut (2002), and 3) mechanical understory cut (2002) followed by 2 burns (2003 and 2006). We captured fewer salamanders in mechanical twice-burned treatment areas than in twice-burned and control treatment areas, but we captured more lizards in mechanical twice-burned treatment areas than in other treatment areas. Higher lizard captures in mechanical twice-burned treatment areas likely was related to increased ground temperatures and greater thermoregulatory opportunities. Higher and more variable ground temperatures and faster drying of remaining litter and duff may have led to fewer salamander captures in mechanical twice-burned treatment areas. Our longer term results, after 2 prescribed burns, differ from shorter term results. After one prescribed burn at the same site, eastern fence lizard (Sceloporus undulatus) captures were greater in mechanical burn treatment areas but salamander captures did not differ among treatment areas. Our results indicate that multiple (≥2) fuel-reduction treatments that decrease canopy cover may benefit lizards but negatively affect salamanders.

Response of Reptiles and Amphibians to Repeated Fuel Reduction Treatments

Abstract:Recent use of prescribed fire and fire surrogates to reduce fuel hazards has spurred interest in their effects on wildlife. Studies of fire in the southern Appalachian Mountains (USA) have documented few effects on reptiles and amphibians. However, these studies were conducted after only one fire and for only a short time (1–3 yr) after the fire. From mid‐May to mid‐August 2006 and 2007, we used drift fences with pitfall and funnel traps to capture reptiles and amphibians in a control and 3 replicated fuel‐reduction treatments: 1) twice‐burned (2003 and 2006), 2) mechanical understory cut (2002), and 3) mechanical understory cut (2002) followed by 2 burns (2003 and 2006). We captured fewer salamanders in mechanical + twice‐burned treatment areas than in twice‐burned and control treatment areas, but we captured more lizards in mechanical + twice‐burned treatment areas than in other treatment areas. Higher lizard captures in mechanical + twice‐burned treatment areas likely was related to increased ground temperatures and greater thermoregulatory opportunities. Higher and more variable ground temperatures and faster drying of remaining litter and duff may have led to fewer salamander captures in mechanical + twice‐burned treatment areas. Our longer term results, after 2 prescribed burns, differ from shorter term results. After one prescribed burn at the same site, eastern fence lizard (Sceloporus undulatus) captures were greater in mechanical + burn treatment areas but salamander captures did not differ among treatment areas. Our results indicate that multiple (≥2) fuel‐reduction treatments that decrease canopy cover may benefit lizards but negatively affect salamanders.

Carbon recovery rates following different wildfire risk mitigation treatments

Sequestered forest carbon can provide a climate change mitigation benefit, but in dry temperate forests, wildfire poses a reversal risk to carbon offset projects. Reducing wildfire risk requires a reduction in and redistribution of carbon stocks, the benefit of which is only realized when wildfire occurs. To estimate the time needed to recover carbon removed and emitted during treatment, we compared the 7-year post-treatment carbon stocks for mechanical thinning and prescribed fire fuels reduction treatments in Sierra Nevada mixed-conifer forest and modeled annual carbon accumulation rates. Within our 7-year re-sample period, the burn only and understory thin treatments sequestered more carbon than had been removed or emitted during treatment. The understory thin and burn, overstory thin, and overstory thin and burn continued to have net negative carbon stocks when emissions associated with treatment were subtracted from 7-year carbon stock gains. However, the size of the carbon deficit in the understory thin and burn 7 years post-treatment and the live tree growth rates suggest that the remaining trees may sequester treatment emissions within several more years of growth. Overstory tree thinning treatments resulted in a large carbon deficit and removed many of the largest trees that accumulate the most carbon annually, thereby increasing carbon stock recovery time. Our results indicate that while there is an initial carbon stock reduction associated with fuels treatments, treated forests can quickly recover carbon stocks if treatments do not remove large, fire-resistant overstory trees.

Bryoid Layer Response to Soil Disturbance by Fuel Reduction Treatments in a Dry Conifer Forest

We investigated the response of the bryoid layer, bryophyte and lichen communities on the soil surface, three years after fuel reduction treatment (logging and burning) in the central Blue Mountains of eastern Oregon. Both treatment and control areas had been decimated by spruce budworm and drought before the fuel reduction treatments. Treatments reduced overstory and understory woody vegetation, litter, and coarse woody debris and disturbed the soil surface. In the untreated stands minor local disturbances had created bare mineral soil over about 1% of the ground area, about half of that was from burrowing rodents. Fuel reduction treatments disturbed an additional 23% of the ground area, beyond the 1% disturbed in untreated sites. Over half of the recently disturbed treatment areas had been colonized by pioneering short mosses. Bare soil from rodent disturbances covered about 10 times more area in treated sites than in untreated sites, increasing from 0.4% to 5.5% cover. The bryoid layer responded to the treatments by changes in species composition, rather than species richness. Treated areas had more cover of small acrocarpous pioneer bryophytes (i.e., Funaria hygrometrica, Ceratodon purpureus, and especially Bryum caespiticium), whereas cover of larger pleurocarps, such as Brachythecium and Rhytidiadelphus was reduced by soil disturbance. We infer that pioneer bryophytes perform a valuable ecosystem service in these dry forests by rapidly colonizing and stabilizing the soil surface, reducing its vulnerability to erosion by wind and water.

Fuel Reduction Management Practices in Riparian Areas of the Western USA

Two decades of uncharacteristically severe wildfires have caused government and private land managers to actively reduce hazardous fuels to lessen wildfire severity in western forests, including riparian areas. Because riparian fuel treatments are a fairly new management strategy, we set out to document their frequency and extent on federal lands in the western U.S. Seventy-four USDA Forest Service Fire Management Officers (FMOs) in 11 states were interviewed to collect information on the number and characteristics of riparian fuel reduction treatments in their management district. Just under half of the FMOs surveyed (43%) indicated that they were conducting fuel reduction treatments in riparian areas. The primary management objective listed for these projects was either fuel reduction (81%) or ecological restoration and habitat improvement (41%), though multiple management goals were common (56%). Most projects were of small extent (93% < 300 acres), occurred in the wildland-urban interface (75%), and were conducted in ways to minimize negative impacts on species and habitats. The results of this survey suggest that managers are proceeding cautiously with treatments. To facilitate project planning and implementation, managers recommended early coordination with resource specialists, such as hydrologists and fish and wildlife biologists. Well-designed monitoring of the consequences of riparian fuel treatments on fuel loads, fire risk, and ecological effects is needed to provide a scientifically-defensible basis for the continued and growing implementation of these treatments.

Effects of Fuel-Reduction Treatments on Pollinators in a Pinyon-Juniper Woodland (Arizona)

Effects of Fuel-Reduction Treatments on Pollinators in a Pinyon-Juniper Woodland (Arizona)

A comparison of landscape fuel treatment strategies to mitigate wildland fire risk in the urban interface and preserve old forest structure

We simulated fuel reduction treatments on a 16,000 ha study area in Oregon, US, to examine tradeoffs between placing fuel treatments near residential structures within an urban interface, versus treating stands in the adjacent wildlands to meet forest health and ecological restoration goals. The treatment strategies were evaluated by simulating 10,000 wildfires with random ignition locations and calculating burn probabilities by 0.5 m flame length categories for each 30 m × 30 m pixel in the study area. The burn conditions for the wildfires were chosen to replicate severe fire events based on 97th percentile historic weather conditions. The burn probabilities were used to calculate wildfire risk profiles for each of the 170 residential structures within the urban interface, and to estimate the expected (probabilistic) wildfire mortality of large trees (>53.3 cm) that are a key indicator of stand restoration objectives. Expected wildfire mortality for large trees was calculated by building flame length mortality functions using the Forest Vegetation Simulator, and subsequently applying these functions to the burn probability outputs. Results suggested that treatments on a relatively minor percentage of the landscape (10%) resulted in a roughly 70% reduction in the expected wildfire loss of large trees for the restoration scenario. Treating stands near residential structures resulted in a higher expected loss of large trees, but relatively lower burn probability and flame length within structure buffers. Substantial reduction in burn probability and flame length around structures was also observed in the restoration scenario where fuel treatments were located 5–10 km distant. These findings quantify off-site fuel treatment effects that are not analyzed in previous landscape fuel management studies. The study highlights tradeoffs between ecological management objectives on wildlands and the protection of residential structures in the urban interface. We also advance the application of quantitative risk analysis to the problem of wildfire threat assessment.

Short-Term Effects of Fuel Reduction Treatments on Herpetofauna from the Southeastern United States

Abstract Path analysis of fuel reduction treatments on herpetofauna across four southeastern sites of the National Fire and Fire Surrogate Study provided quantitative evidence relating changes in vegetation and fuels to herpetofauna response. Fuel reduction treatments included prescribed burning (B), a mechanical treatment (M), mechanical treatment followed by prescribed burning (MB), and an untreated control (C). Treatment effects on herpetofauna response variables were predicted by the direct and indirect effects of stand basal area, coarse woody debris volume, native herb cover, and forest floor depth. Path models were solved for lizard, snake, and reptile response to fuel reduction treatments. Lizard and reptile abundance were higher in B and MB plots than in C and M plots. Increasing native herb cover best predicted lizard and reptile abundance within B and MB plots. Native herb cover, lizard, and reptile abundance were highest in B and MB plots, and each of these response variables responded positively to B and MB.