Reds Meadow Blowdown Fire/Fuels Specialist Report. Mammoth Ranger District Inyo National Forest Region 5, USDA Forest Service

Transcription

1 Reds Meadow Blowdown Fire/Fuels Specialist Report Mammoth Ranger District Inyo National Forest Region 5, USDA Forest Service Prepared By: Michèle Slaton, GIS Specialist, INF Alan Taylor, Fire Planner, INF Reviewed by: Phil Bowden, Fuels Manager, RO Dale Johnson, Interagency Vegetation Management Program Leader, Bishop BLM Jeff Iler, Interagency Fire Management Officer, INF

2 Introduction Reds Meadow Valley is located in the Middle Fork of the San Joaquin 5 th field watershed on the Mammoth Ranger District of the Inyo National Forest. The proposed project is a treatment of wind-fallen trees caused by a wind event in 2011, which resulted in fuel accumulation that is a fire and safety hazard to this recreational area with a single exit route. Proposed treatments cover approximately 220 acres, and occur within a project area boundary that consists of Inyo National Forest lands outside wilderness and within the Reds Meadow Valley (3,038 acres). A broader analysis area was also considered for this report, which consists of the Upper Middle and Middle Middle Forks of the San Joaquin River (6 th field watersheds), and includes 49,769 acres, ranging from 5,346 13,143 ft. elevation. The analysis area has a mean slope of 38%, with south and southwest aspects prevalent, although all slopes and aspects are represented. This report provides a summary of existing conditions and environmental consequences of the project in terms of fire risk and safety, and also in terms of ecological conditions and trends related to fire and fuels. Existing Condition Vegetation and climate Vegetation in the analysis area ranges from mixed conifer to red fir, mountain hemlock, lodgepole pine, whitebark pine, and alpine. Vegetation in the proposed project area consists of red fir and lodgepole pine, with some mixed conifer stands. Climate in the analysis area is characterized by warm to cool, dry summers, and cold winters with snowfall. Table 1 shows climate data for the analysis area between , derived from PRISM Climate Group (2012). Table 1. Climate data for analysis area, Mean Range Annual precipitation (in) Maximum summer temperature (F) Minimum winter temperature (F) *Values shown were interpolated using a kriging method in ArcGIS to a 187 m grid. Fire history Fire history data for cross-sectioned trees, snags, and logs from ten sites in the Devils Postpile National Monument, adjacent to the project area, indicate a near absence of fire on the landscape over the last century. Prior to that, mean fire interval was years, with the range of single fire intervals between 3 and 30 years (Caprio et al., 2006). Upper montane zone Van Wagtendonk and Fites-Kaufman (2006) provided a comprehensive evaluation of the fire history in the upper montane zone of the Sierra Nevada. Characterized by a winter-long snowpack and the presence of California red fir, this zone also includes western white pine, quaking aspen, western juniper, Jeffrey pine, and tufted hairgrass. Forest stands are broken by wet meadows, stands of montane 1

3 chaparral, and bare rock. Many plant species have fire-resistant characteristics and, to varying degrees, respond favorably to fire. Generally, the grasses reseed or regrow quickly, the shrubs and hardwoods resprout, and the conifers are protected from lower intensity fire by thick bark and their ability to survive low to moderate crown scorch. Lightning occurrence is higher than in the Lower Montane zone, but not as pervasive as in the Subalpine forest above. California red fir fuel beds are among the heaviest and most compact found in the Sierra Nevada. They typically ignite and carry fire only under extremely dry and windy conditions. At upper elevations of the red fir range, fire creates canopy openings in lodgepole pine that allow the establishment of fir. Where lodgepole pine occurs under a red fir canopy, it will eventually be succeeded by red fir. Montane chaparral becomes established in areas of red fir burned by crown fire, but is eventually overtopped by red fir and Jeffrey pine. Jeffrey pine, western juniper and western white pine stands typically burn with moderate intensity, with Jeffrey pine having the highest intensities due to more litter and duff in the fuel bed. Older trees of all three species usually survive these fires. Jeffrey pine will be replaced by manzanita if high severity fires occur frequently, or by red fir if the period between fires is sufficiently long. Quaking aspen usually only burns if a fire from adjacent stands occurs in late summer, when the herbaceous understory has dried sufficiently to carry fire. As a vigorous sprouter, it will recolonize burns at the expense of conifers. Similarly, occasional late summer fires in tufted hairgrass meadows reduce conifer encroachment. Subalpine forest Subalpine forest is found between the upper montane and alpine meadows and shrublands. Climate is characterized by cool summers and cold winters, with all precipitation falling as snow except for occasional thunderstorms. The snow-free period is usually mid-june to late October. Lightning is pervasive, although ignitions are infrequent in the compact fuel beds. Surface fires are usually low intensity but may be moderately severe. Stand replacing fires with return intervals of years occur in lodgepole pine particularly in areas of cold air drainage. Lodgepole pine is replaced by mountain hemlock and whitebark pine as tree line is approached, but will out-compete them in burn areas. Occasional western white pines are also found in the subalpine zone of the analysis area. Subalpine trees are easily killed by fire at a young age but develop increased resistance as they age. Lodgepole pine has thin bark and flammable foliage. Individual trees can be easily killed by low intensity surface fire, but openings are usually recolonized quickly. Occasional crown fires can consume entire stands and are also recolonized quickly from seed. Sierra Nevada lodgepole cones are sometimes serotinous, but may open at maturity and disperse over a 2 year period. Mountain hemlocks are similar to lodgepole pine while young, but mature trees develop thicker bark, giving them some protection. Whitebark pine develops a moderately thick bark and mature trees can survive low- and sometimes moderate-intensity fires. It also survives because large refugial trees are scattered in areas of patchy fuels. Deep, compact duff layers attest to the infrequency of fire in the subalpine forest. Fire Cause Roughly 44% of fires on the north end of the Inyo NF since 1970 are human caused. The Mammoth Ranger District has a human caused rate of 62%, which is similar to the analysis area (Table 2). Human caused fires often lack the wetting rains and/or cloud cover associated with lightning fires, 2

4 and, thus, have an increased probability of burning under more severe conditions. These fires are also usually in areas with higher values at risk (structures, trails, campgrounds, people, etc). The blowdown area has a slightly lower incidence of human caused fires, possibly due to more limited access. The project area has a much higher risk of human caused fires than the surrounding areas because of the high level of recreational use. There is no known fire history in the treatment areas. Table 2. INF Fire History Since 1970 from Fire Family Plus (Brittain, 2008). Total Fire Number by Cause Size Class (All Fires) Acres # of % of % of Fires Human Lightning Total Total A B C D E F G Analysis Area 129,418* Blowdown Area 15, Project Area 3, Treatment Area *The analysis area for this metric was larger than that used elsewhere of 49,769 acres. The larger value of 129,418 acres represents the smallest rectangle surrounding the 49,769 analysis area, and was used in some portions of the spatial modeling. Fire regime condition class Fire regime condition class (FRCC) is a classification of the degree of departure of ecosystem conditions at a given time from historic reference conditions. This departure may result in changes to key ecosystem components, such as species composition and mosaic pattern (Hann et al., 2010). Comparisons between pre-euroamerican settlement and contemporary fire return intervals (FRIs), and calculated departures from the pre-euroamerican settlement FRIs are available for National Forests in R5 (Safford et al., 2011). This dataset was created prior to the blowdown event, so information is presented only as a reference for recent ecological trends in the analysis area, and not as an analysis of changes in FRI that may result from the blowdown or the proposed treatment. These data are summarized for forested vegetation types in the analysis area in Table 3. Table 3. Mean reference Fire Return Intervals for the forested lands in the analysis area (49,769 acres) The number of years in the fire record divided by the number of fires occurring Current FRI 96 between 1908 and 2011 (plus 1) Mean Ref FRI 70 How often a fire regime likely burned yrs prior to settlement Median Ref FRI 33 The median reference FRI (half the observations were above this value, half below) RangeRef FRI The range of minimum to maximum reference FRIs reported in the literature Mean Freq Departure 40% The departure of current FRI from reference mean FRI in percent (fire return interval departure, FRID). [1-(MeanRefFRI/CurrentFRI)]*100 Mean Condition Class 2 The mean condition class (FRI) is a measure of the extent to which contemporary fires are burning at frequencies similar to frequencies that occurred prior to Euroamerican settlement, with mean reference FRI as the basis for comparison. This metric categorizes the differences in MeanFreqDep using the following scale: 0 to 33% departure = CC1, 33 to 67% departure = CC2, and >66% departure = CC3. 3

5 The mean reference FRI, or best estimate of FRI prior to Euroamerican settlement, was 70 years. The FRI is longer than that found within the Devils Postpile National Monument (NM) because the entire analysis area includes a large proportion of subalpine forest and alpine environments, where FRIs are greater than in the montane forests. The current FRI across the analysis area is 96 years, resulting in a mean FRI departure of 40%. This corresponds to a mean fire regime condition class of 2, which indicates moderate departure from pre-settlement conditions in the current landscape. Combined with the sitespecific data from Devils Postpile NM (Caprio et al., 2006), these sources indicate that absence of fire on the landscape over the last century has resulted in ecological conditions unlike those in prior, recorded history. Though not a direct measure of fire risk, we can infer that fuel accumulation over the last century could result in fires with greater severity compared to historic conditions. Fuel conditions Between Nov. 30 and Dec. 1, 2011, extreme winds caused a blowdown event, uprooting trees of various sizes, and resulting in large numbers of down trees in developed areas, near roads, and along trails in Reds Meadow Valley. Limited availability of imagery during winter months has precluded precise measurement of the blowdown perimeter. However, preliminary models based on surveyed trails indicate that wind-fallen trees of varying concentration occur over an area of 15,000 acres, with the densest areas covering as much as 500 acres. The species and size of down trees varies, but they are predominantly mature red fir and lodgepole pine in the project area. Preliminary surveys estimate an average of 54 wind-fallen trees per acre in patches with severe wind damage. Fire size in this region of the Sierra Nevada is generally larger on south and west facing slopes and smaller on north and east-facing slopes, due to more continuous shrub cover on south and west aspects. Much of the blowdown area occurs on north aspects, resulting in newly formed continuity of fuels with potential for increased severity of fires and larger fire sizes. The depth and density of down trees in the project area constitutes an extremely high concentration of surface fuel. The heavy fuel conditions can quickly lead to wildland fires that escape initial containment efforts, and become high-intensity, stand-replacing burns, which are both difficult and dangerous to control. The needles and small limbs on fallen trees dry out quickly, usually within 1-2 years. The larger limbs and boles of fallen trees take longer to dry out, perhaps within 3-10 years. In the longer term, there is high risk of fire burning with high intensity and for long duration in these larger fuels. An adequate description of the fuels on a site requires identifying the existing fuel components including duff, litter, dead-down woody materials, grasses and forbs, shrubs, and the tree canopy (Graham et al., 2004), which in turn defines the fuel model. Fuel loading, size class distribution of the load, and its arrangement (compactness or bulk density) determine whether an ignition will result in a sustaining fire. Prior to the blowdown, the project area was mainly represented by fuel model 185, which is representative of conifer stands with heavy forest litter including dead and down woody material, along with a thick shrub or small tree understory (Scott and Burgan, 2005). The project area also contains some fuel model 183, characterized by small down logs, with a moderate load of fine litter. Other areas were belonged to fuel model 187, characterized by larger diameter down logs. Since the 2011 wind event, a large proportion of the project area has shifted to a fuel model of high load blowdown (Model 204, Scott and Burgan, 2005), which is characterized by an uncompacted fuelbed, with very high rate of fire spread, and very high flame lengths. 4

6 Wildland Urban Interface The Sierra Nevada Forest Plan Amendment (USDA Forest Service, 2004) outlines desired conditions for Wildland Urban Interface (WUI). The Healthy Forest Restoration Act of 2003 identified areas to be included in the WUI. WUI contains two zones outside the urban core: 1) the defense zone, which extends out approximately 0.25 miles from structures, and 2) the threat zone, which extends approximately 1.25 miles beyond that for a total of 1.5 miles. Fuel treatments in the defense zone are to be the most intense, designed to prevent the loss of life and property by creating defensible space. Strategically placed fuel treatments have been shown to interrupt wildland fire spread and reduce fire intensity in similar environments within WUI in the Lake Tahoe Basin and Southern Cascades (Schmidt et al., 2008; Safford et al., 2009). Proposed treatments in Reds Meadow will be designed to modify behavior of wildland fires within the defense and threat zones. By focusing on specific areas within these zones, firefighters will be able to take advantage of reduced spotting in developed areas, lower rates of spread, and reduced crown fire activity, to more effectively attack and contain fires approaching the urban core. Desired Conditions The 2004 Sierra Nevada Forest Plan Amendment (USDA Forest Service, 2004) identifies desired conditions for WUI defense and threat zones. Desired conditions focus on enabling successful attack and containment of wildland fire and providing for visitor, resident, and firefighter safety, as well as structure protection. Specific wildland fire goals include reducing flame lengths, rates of spread, and crown fire activity. Flame lengths greater than 4 feet are often too intense for hand tools, although dozers and engines can still attack the fire directly until flame lengths exceed 8 feet. If the fire s rate of spread is faster than the fireline production rate, the fire will continue to grow out of control, even if flame lengths are under threshold. Flame lengths greater than 8 feet are often beyond the capability of fire suppression resources to control. Crown fires have the potential to produce flame lengths greater than 100 feet and travel at least 1 mile per hour (Graham et al., 2004). Large numbers of firebrands can be produced and injected into the wind stream which can result in both short and long range spotting. Desired conditions for the defense zone are: Stands are fairly open and dominated primarily by larger, fire tolerant trees Surface and ladder fuel conditions are such that crown fire ignition is highly unlikely The openness and discontinuity of crown fuels, both horizontally and vertically, result in very low probability of sustained crown fire Desired conditions for the threat zone are: Flame lengths at the head of the fires are less than 4 feet Rate of spread at the head of the fire is reduced to at least 50 percent of pre-treatment levels Hazards to firefighters are reduced by managing snag levels in locations likely to be used for control of prescribed fire and fire suppression consistent with safe practices guidelines Production rates for fire line construction are doubled from pre-treatment levels 5

7 Tree density is reduced to a level consistent with the site s ability to sustain forest health during drought conditions Environmental Consequences Issues Addressed Fire suppression has been effective in the Reds Meadow area over the last century (Caprio et al., 2006), resulting in longer fire return intervals and changes in landscape vegetation patterns. Longer fire return intervals allow more time for surface fuels to grow and accumulate, resulting in higher fuel loadings and greater fuel continuity. Increased fuel continuity, surface fuel loading, and ladder fuel development combine to create a situation conducive to undesirable fire behavior, such as a surface fire burning at high intensity and/or transitioning to a crown fire. Research has identified four principles that can be applied to mitigate the potential for high severity crown fire and help achieve the desired conditions identified above: surface fuel reduction, increasing crown base height, decreasing crown density, and retaining large trees of fire-resistant species (Agee, 2002; Agee and Skinner, 2005; Peterson et al., 2005). Management tools available to achieve desired conditions include mechanical treatment and prescribed fire. Evidence from the Dinkey Landscape area on the Sierra National Forest, approximately 36 air miles southwest of the project area, suggests that both mechanical and prescribed fire treatments are effective in achieving desired conditions as outlined above (Dinkey Collaborative Group, 2010). Extreme fuel conditions in the Reds Meadow Valley caused by the blowdown event preclude prescribed fire as a feasible tool in many areas. Furthermore, attempts to restore pre-european fire frequencies and forest conditions are complicated in the face of climate change (North et al., 2009). As a result, methods used to achieve desired conditions should focus on affecting fire behavior by manipulating fuel conditions in strategic areas, while allowing natural processes to reach equilibrium under modern climate conditions. Smaller treatments based on local knowledge of prevailing winds, weather, and fire behavior in the most vulnerable areas may be the most effective tool to provide immediate protection to the Reds Meadow Valley (North, 2012). Differences between alternative actions in yarding method and temporary road and bridge construction will not impact the primary issues addressed for fuels and are not considered in this report. Indicators A set of indicators and measures will be used to evaluate each alternative s ability to address the issues identified. Indicators were derived from desired conditions for WUI as identified above. Thresholds for flame length and rate of spread were defined in the Sierra Nevada Forest Plan Amendment (USDA Forest Service, 2004). Specific thresholds were not identified for crown fire activity; instead, analyses were based on the goals of reducing crown fire activity, and improving the ability for firefighters to suppress fires safely and rapidly in this area with limited opportunity for recreationists to exit in the event of fire. Indicators included: Flame length (feet) Rate of spread (chains per hour) Crown Fire Activity (surface fire, passive crown fire/torching, active crown fire) 6

8 Methodology Fire behavior spatial modeling The consequences of each alternative to fuel condition and fire behavior were compared using spatial models. Fuel model, canopy cover, stand height, canopy base height, canopy bulk density, elevation, slope, and aspect data were acquired from Landfire (Landfire Data Access tool) in ArcGIS 10. The Landfire Total Fuel Change (LFTFC Version0.12) tool was used to create landscape files showing conditions prior to the blowdown event, after the blowdown event, and following treatments in the alternatives. The 2008 Landfire dataset (LF110 Refresh 2008, Zone 6) was used (Landfire, 2012). Existing Vegetation Height (EVH) and Existing Vegetation Cover (EVC) classes are two of the inputs for the spatial models and were obtained from the Landfire dataset. However, because the Landfire dataset was acquired prior to the blowdown, EVH and EVC for the blowdown were estimated based on existing imagery and preliminary surveys of the project area. The ruleset applied to EVH and EVC for the blowdown is available on request. In general, reduction in vegetation height and cover as a result of the blowdown was estimated to be greatest in valley bottoms and on north aspects. It is anticipated that the treatments themselves will not alter the standing canopy of trees, so EVH and EVC were not altered for treatment areas. However, because the treatments are designed to alter the fuel model, treatments were assigned to fuel model 101, which is representative of sparse dry fuels and low flame lengths. Spatial modeling was completed using FlamMap version 2.0 (Finney et al., 2006). Model assumptions and limitations can be found in Finney (2006) and Stratton (2006), and a recent review of caveats involved in spatial fuels modeling is given by North et al. (2012). Models for each alternative were run using wind, weather, and fuel conditions as shown in Table 4. Table 4. Weather conditions used as inputs to spatial models. Fuel moisture 1 hr = 3, 10 hr = 4, 100 hr = 7, live woody = 60, live herbaceous = 100% Wind direction 225 (deg from N) Windspeed 25 mph Foliar moisture 100% Crown fire calculation Scott and Reinhart (2001) method Weather (high temperature, low temperature, high rh, low rh, precip) The 24 hour period prior to ignition was represented as: 2300 temperature = 51, rh = 56; 1400 temp = 81, rh = 15; 0600 temp = 43, rh = 81; 1000 temp = 82, rh = 26; the rain events prior to the Mono fire were excluded to model outcomes under the most extreme potential conditions A dataset from the Crestview remote automated weather station (RAWS), approximately 10 air miles northeast of the project area, was analyzed at the 80 th percentile using Fire Family Plus version (Brittain, 2008) for Wind values were based on prevalent direction. RAWS data for the two week period prior to the Mono Fire (2010) were used. The Mono Fire occurred approximately 18 air miles north of the current project area and provided the nearest dataset to the project area for which complete daily weather records were available. A gridded weather input was used, which accounts for elevational variation in temperature and introduces fuel moisture conditioning into the model. Gridded wind was also used, which accounts for vegetation impact on wind. Values for live herbaceous fuel moisture were based on Scott and Burgan (2005), and Crestview samples since 1989 were used to estimate live woody moisture. Burn probabilities were estimated using 5000 random ignitions. 7

9 FlamMap output files for flame length, rate of spread, crown fire activity, major flow paths, and burn probabilities were exported and converted to ArcGIS grids for comparison. ANOVA and Tukey s HSD test were used to compare flame lengths and rates of spread between alternatives, and proportional differences for crown fire activity and flame length categories were tested using a chi-squared binomial test. All statistical analysis was performed with R statistical package (R Development Core Team, 2012). Cumulative effects Spatial and Temporal Context (bounding of analysis area) for Effects Analysis The cumulative effects analysis is bounded by the entire analysis area for this project, which consists of the Upper Middle and Middle Middle Forks of the San Joaquin River (49,769 acres), and was selected because fires in the project area may begin from or spread to this larger area, and because of relatively uniform fuel conditions and fire safety issues for firefighters and visitors. The cumulative effects assessment is further bounded in time by the limits of past, present, and reasonably foreseeable future actions, over a 10 year horizon into the future. This is an appropriate timeframe because future conditions beyond that cannot be known, and will change with vegetative re-growth and stand development into the future. Past Actions The analysis area is 90% wilderness, and few past actions have impacted fuel conditions here, aside from fire suppression efforts over the last century. Fire suppression activities have had cumulative consequences of fuel accumulation. The effects of past actions were incorporated into the spatial models for the baseline current condition layer (i.e. preexisting conditions, prior to blowdown event), and are therefore represented in all four alternatives considered. Present and Foreseeable Actions No future actions are anticipated on Forest Service lands, but the National Park Service is expected to treat areas within the Devils Postpile NM that were impacted by the blowdown event. Some of these treatments may abut proposed treatments in this project. Summary of Alternatives Actions to be implemented under each alternative are outlined in Table 5. 8

10 Table 5. Summary of alternatives. Alternative Action 1 No action. No tree removal or other fuels reduction activities would be implemented. 2 Proposed action. Ground-based equipment would be used to remove wind-fallen trees on 178 acres in treatment units where slopes are less than 30%. Trees would be removed on 42 acres in areas with steeper slopes using hand labor, and/or cable yarding systems. Slash would be piled and burned, jackpot burned, chipped on site, and/or hauled off site. 3 Tree removal in IRA using a helicopter. The same amount of fuel would be removed as in Alternative 2, but using different methods. For the purpose of this report, Alt. 2 and 3 are identical. 4 No tree removal in IRA. Ground-based equipment would be used to remove wind-fallen trees on 118 acres in treatment units outside of the IRA where slopes are less than 30%. Cable yarding systems would be used to remove trees on approximately 32 acres outside of IRA, where slopes are steeper than 30% in units. Slash would be piled and burned, jackpot burned, chipped on site, and/or hauled off site. Alternative 1 (No Action) If Alternative 1 is selected, fuel treatments would not be implemented. Direct Effects Under this alternative, down logs and fine fuels will continue to accumulate. Wind-fallen lodgepole pine logs may persist on the ground for over a century (Brown et al., 1998), whereas fir logs are expected to decay in decades or less. Fuels will remain vertically and horizontally continuous, resulting in a greater probability of crown fire, thus not meeting desired conditions for the WUI defense zone. Hazardous fuel conditions within the project area will remain untreated and constitute a safety threat for Forest visitors, and for adjacent lands, including the town of Mammoth Lakes. Surface fuel loadings will increase over time as canopy openings allow shrubs to grow. The large, fire resistant trees currently adjacent to the treatment units would remain as long as they continue to successfully compete for resources. These trees would continue to be at risk from wildfire. The single entry and exit road to Reds Meadow Valley limits opportunity for firefighter access and visitor egress in the event of fire. The current conditions of wind-fallen trees will continue to limit suppression crew access to portions of the area and will reduce the speed of control actions. Indirect Effects Because no thinning or fuels treatments would be implemented, only natural changes would result in changes to the fuel profile within the project area. Indirect effects include those caused by wildfire in the project area, and the different responses in potential wildfire behavior. Burn probabilities and major flow paths for fire in the current conditions existing in the project area are shown in Fig. 1. Burn probability is a measure of the chance that an area will carry fire given a number of random ignitions in the vicinity, and Fig. 1 demonstrates the much greater likelihood of fire in the areas where recreation is concentrated in Reds Meadow Valley. Major flow paths under current conditions travel directly through some campgrounds and developed sites. Flame lengths, rates of spread, and potential for crown fire in the event of wildfire are all greatest under this alternative for the proposed treatment area (Table 6; Figs. 2-3); the fuel model in proposed treatment areas would remain high load blowdown (Model 204, Scott and Burgan, 2005), and flame 9

11 lengths and rates of spread would exceed those outlined in desired conditions for the WUI threat zone by the USDA Forest Service (2004). However, when considering the entire project area (3,038 acres), there is only a slight difference in mean flame length and rate of spread for Alternative 1, in comparison to Alternatives 2 & 3, and the difference is not statistically significant (Table 7). Cumulative Effects Vegetation structure will continue to change over time, and within 10 years, fuels will continue to accumulate in the already dense blowdown fuelbed. As a result, potential flame lengths, rate of spread, and crown fire activity are likely to increase. Fuels treatments on adjacent Park Service lands may provide some protection from crown fire activity, excessive flame lengths, and high rates of spread on Forest Service lands, particularly because those treatments would be upwind of the major flow paths for fire identified in Fig. 1, although relatively small areas are expected to be treated (ca. 10 acres). However, because of the extreme fuel loading in the blowdown area, those adjacent treatments are not expected to have a positive effect on reducing flame lengths, rate of spread, or crown fire activity in most developed areas or along the single exit route. Compliance with Forest Plan and Other Relevant Laws, Regulations, Policies and Plans The no action alternative would not contribute to achieving desired condition, as outlined by the USDA Forest Service (2004). Summary of Effects No treatments would occur under this alternative. Extreme fuel conditions in Reds Meadow Valley, characterized by high load blowdown, with very high potential flame lengths and rates of spread, would not meet the desired conditions for WUI defense and threat zone characteristics. Developed recreation sites, including Reds Meadow Resort facilities, would remain threatened by the potential for severe wildfire, and the single entry and exit routes for firefighters and visitors in the event of fire would be jeopardized. Alternatives 2 & 3 These alternatives are considered equivalent for this report, because they would result in identical changes to fuel conditions. They differ only with respect to treatment and yarding method. Alternatives 2 & 3 propose fuel treatments in 220 acres in the Reds Meadow Valley. Under these alternatives, 122 acres would be treated in the WUI defense zone, 97 acres would be treated in the WUI threat zone, and a small portion treated in the urban core. Direct Effects Under these alternatives, down logs and some fine fuels would be removed from the treatment areas. The fuel model in treated areas would change from current status in model of high load blowdown (Model 204, Scott and Burgan, 2005), characterized by a very high rate of fire spread and very high flame lengths, to a model of sparse fuels (Model 101), with low rate of spread and low flame lengths. The reduced number of down logs would increase the ability for firefighters and recreationists to travel on trails, roads, and within the forest. Vertical and horizontal continuity of fuels will be reduced, resulting in a lesser probability of crown fire, in accordance with desired conditions for the WUI defense zone. 10

12 Indirect Effects Natural changes would continue to cause changes to the fuel profile within the treatment area. Other indirect effects are those that would result from potential wildfire in the project area. Alternatives 2 & 3 would result in a significant reduction in the mean flame length and rate of spread, in comparison to Alternative 1 for the treatment units (Table 6; Figs. 2-3). In addition, across the larger project area, Alternatives 2 & 3 would cause a significant drop in the proportion of flame lengths that are above the threshold value of 4 ft., identified above as the desired condition for the WUI threat zone. No threshold value was defined for crown fire activity, but the 6% reduction passive crown fire in Alternatives 2 & 3, compared to no action, may be a wide enough margin to allow for firefighter and visitor safety in extreme events. These alternatives would result in a 43% reduction in predicted rate of spread within the treatment units, compared to no action (Table 6). However, further treatment would be required to meet desired condition of a 50% reduction in rate of spread across the entire project area (Table 7). Further treatment would also be required to eliminate all flame lengths greater than 4 ft. and to eliminate all crown fire activity within the project area and WUI defense and threat zones, as outlined by the USDA Forest Service (2004). Major flow paths and burn probabilities do not differ between alternatives; Fig. 1 represents conditions for all alternatives. Flow paths are primarily determined by terrain in this case, and as a result, it is especially important that Alternatives 2 & 3 achieve a reduction in flame lengths and rates of spread in those highly vulnerable areas, including developed recreation sites that occur in the most likely direct path of wildfire. Table 6. Comparison of expected fire behavior under each alternative across the treatment units only (220 acres). Preexisting (Prior to blowdown) Alternative 1 (No action; current conditions) Alternatives 2 & 3 (Treatment of all proposed units) Alternative 4 (Treatment only outside IRA) Flame length (ft) 3.3 +/ / / /- 6.2 Proportion (%) of treatment area with flame lengths > 4 ft. Rate of spread (chains/hr) 5 +/ / / /- 13 Crown fire activity 2% no fire, 77% surface, 21% passive crown, 0% active crown 2% no fire, 2% surface, 96% passive crown, 0% active crown 2% no fire, 73% surface, 25% passive crown 2% no fire, 48% surface, 50% passive crown *Alts. 2-4 all have significant differences in flame length, rates of spread, and crown fire activity from the no action alternative (p < 0.01). Alternatives 2 & 3 significantly reduce lengths compared to Alt. 4 (p < 0.01). 11

13 Table 7. Comparison of expected fire behavior under each alternative across the project area (3,038 acres). Preexisting Alternative 1 (No action) Alternatives 2 & 3 (Treatment of all proposed units) Alternative 4 (Treatment only outside IRA) Flame length (ft) / / / / Proportion (%) of project area with flame lengths > 4 ft. Rate of spread (chains/hr) / / / / Crown fire activity 3% no fire, 55% surface, 36% passive crown, 6% active crown 3% no fire, 23% surface, 71% passive crown, 2% active crown 12 3% no fire, 30% surface, 65% passive crown, 2% active crown* 3% no fire, 27% surface, 68% passive crown, 2% active crown* *Alts. 2-4 all have significant proportional difference in crown fire activity from the no action alternative (p < 0.01). Differences are not significant among alternatives for flame length or rate of spread (p > 0.1). Cumulative Effects Vegetation structure will continue to change over time, and within 10 years, vegetation in the treatment area is expected to convert from herbaceous-dominated types to shrubland with tree regeneration. As a result, potential flame lengths, rate of spread, and crown fire activity are likely to increase. Monitoring may be used to determine whether additional treatment will be necessary to maintain desired conditions. This project will be entered into a pool for selection of a subset of projects to monitor for fuel treatment effectiveness on the Inyo NF, including pre- and post-treatment measurements. Fuels treatments on adjacent Park Service lands may provide some protection from crown fire activity, excessive flame lengths, and high rates of spread on Forest Service lands, particularly because those treatments would be upwind of the major flow paths for fire identified above, although relatively small areas are expected to be treated (ca. 10 acres). Those treatments are expected to have a positive cumulative effect on achieving desired conditions; greater contiguous areas with reduced fuel loading will provide extra protection for the strongly threatened developed sites at the south end of the project area, near Reds Meadow Resort. Compliance with Forest Plan and Other Relevant Laws, Regulations, Policies and Plans Alternatives 2 & 3 would contribute to achieving desired conditions for WUI defense and threat zones as outlined by the USDA Forest Service (2004) in the treatment areas (220 acres), but would not fully meet desired conditions. To a lesser extent, these alternatives would contribute toward desired conditions being met in the broader project area (3,038 acres) and entire analysis area (49,769 acres). Summary of Effects Under Alternatives 2 & 3, 220 acres of high load blowdown fuels would be treated. Potential flame lengths, rate of spread, and crown fire activity would be reduced in the treatment area, and contribute toward meeting desired conditions for visitor and firefighter safety and structural protection. Further treatment would be required to fully meet desired conditions for the project area. These alternatives will reduce wildfire threat in small, but targeted areas in the most heavily visited areas of Reds Meadow, and along the single corridor that serves as an escape route in the event of wildfire.

14 Alternative 4 Alternative 4 proposes fuel treatments only outside Inventoried Roadless Area (IRA), on 150 acres in the Reds Meadow Valley. Under this alternative, 69 acres would be treated in the WUI defense zone, and 81 acres would be treated in the WUI threat zone. Direct Effects Under this alternative, some down logs and fine fuels would be removed from the treatment areas. The fuel model in treated areas would change from current status of high load blowdown (Model 204, Scott and Burgan, 2005), characterized by a very high rate of fire spread, and very high flame lengths to a model of sparse fuels (Model 101), with low rate of spread and flame lengths. The reduced number of down logs would increase the ability for firefighters and recreationists to travel on trails, roads, and within the forest. Vertical and horizontal continuity of fuels will be reduced, resulting in a lesser probability of crown fire, in accordance with desired conditions for WUI defense zones, though not to the same level as Alternatives 2 & 3. Only one-half the acreage of treatment would occur in the defense zone as compared to Alternatives 2 & 3, and would thus not be in accordance with desired conditions for the defense zone, where treatments should be more intense. Indirect Effects Natural changes would continue to cause changes to the fuel profile within the project area. Other indirect effects are those that would result from potential wildfire in the project area. Within the treatment areas, Alternative 4 would result in a significant reduction in the mean flame length and rate of spread in comparison to Alternative 1 (Table 6). Crown fire activity would be reduced by 6% in comparison to no action. However, because fewer acres would be treated as compared to Alternatives 2 & 3 (approx. 70 acres less), Alternative 4 would be less effective at achieving desired conditions. This alternative would result in a 30% reduction in predicted rate of spread within the treatment units, which is less than the 50% reduction outlined in desired conditions for WUI threat zones (Table 6). Across the entire project area, Alternative 4 would result in a slight, but statistically insignificant reduction in flame lengths and rate of spread. However, the drop in the proportion of flame lengths in the project area that are above the threshold value of 4 ft. would not be as great as in Alternatives 2 & 3 (Tables 6 & 7; Figs. 2-3). To achieve desired conditions for flame lengths, rate of spread, and crown fire activity, further treatments would be required in the Reds Meadow Valley. The differences between Alternatives 2 & 3 and Alternative 4 are most notable at the south end of the project area. The treatments in IRA that would not be conducted under Alternative 4 include 54 acres of WUI defense zone and 16 acres of WUI threat zone. This will result in exposure of developed areas to greater flame lengths and rates of spread, and create conditions that cannot be contained by firefighters. As a result, fuel conditions surrounding the Reds Meadow Resort cabins, café, store, employee housing, pack station, and campground would not meet the desired conditions as outlined by the USDA Forest Service (2004). Alternative 4 would limit the extent of defensible space around these structures, in comparison to Alternatives 2 & 3, and may limit the use of the single evacuation route in the event of fire. Cumulative Effects Vegetation structure will continue to change over time, and within 10 years, vegetation in the treatment area is expected to convert from herbaceous-dominated types to shrubland, with tree regeneration. As a result, potential flame lengths, rate of spread, and crown fire activity are likely to 13

15 increase. Monitoring may be used to determine whether additional treatment will be necessary to maintain desired conditions. This project will be entered into a pool for selection of a subset of projects to monitor for fuel treatment effectiveness, including pre- and post-treatment measurements. Fuels treatments on adjacent Park Service lands may provide some protection from crown fire activity, excessive flame lengths, and high rates of spread on Forest Service lands, particularly because those treatments would be upwind of the major flow paths for fire identified in Fig. 1, although relatively small areas are expected to be treated (ca. 10 acres). Those treatments are expected to have a positive cumulative effect on achieving desired conditions. However, the positive effect is expected to be less than that for Alternatives 2 & 3 because Alternative 4 excludes treatments in IRA, which occur at the south end of the project area and adjacent to potential NPS treatments. Compliance with Forest Plan and Other Relevant Laws, Regulations, Policies and Plans Alternatives 4 would contribute to achieving desired condition for WUI defense and threat zones as outlined by the USDA Forest Service (2004) in the treatment areas (220 acres), but would not fully meet them. To a lesser extent, this alternative would contribute toward desired conditions being met in the broader project area (3,038 acres) and entire analysis area (49,769 acres). In comparison with Alternatives 2 & 3, this alternative falls short in providing protection to 54 acres in the WUI defense zone surrounding one of the highest use developed recreation sites in the Valley, where treatments should be designed with adequate intensity to provide for human and structural safety. Summary of Effects Under Alternative 4, 150 acres of high load blowdown would be treated. Potential flame lengths, rate of spread, and crown fire activity would be reduced in the treatment areas, and contribute toward meeting desired conditions for visitor and firefighter safety and structural protection in the treatment area. Further treatment would be required to fully meet desired conditions for the treatment and project areas. This alternative will reduce wildfire threat in some developed areas in Reds Meadow Valley, but will fail to provide needed protection in the south portion of the project area and along the single escape corridor. Conclusion A blowdown event that occurred in the Reds Meadow Valley in 2011 resulted in the uprooting of large numbers of trees over at least 500 acres, including developed areas, near roads, and along trails. Fire has been mostly absent on the landscape over the last century, whereas prior to that, the mean fire return interval was years, with a maximum mean estimate of 70 years. The current fire return interval across the analysis area is 96 years, resulting in a mean departure from pre-euroamerican settlement conditions of 40%. This corresponds to a mean fire regime condition class of 2, which indicates moderate departure from pre-settlement conditions in the current landscape. As a result, fuel accumulation over the last century, in addition to the recent blowdown event, has resulted in unprecedented fuel conditions that pose a risk to visitors, developed areas, firefighters, and natural resources. The proposed action would treat 220 acres within Reds Meadow Valley and create more openness and discontinuity of fuels. Both Alternative 2 (Proposed) and Alternative 3 would result in the same outcome with regard to fuel conditions. Both alternatives would make progress toward meeting desired conditions as outlined in the Sierra Nevada Framework for fuel continuity, flame length, rate of spread, and crown fire activity. Both would assist in creating conditions that enable safer exit routes for visitors 14

16 in the event of fire. They would also provide better access for firefighters, in addition to fire behavior conditions with a better chance of successful attack. Alternative 4 would result in some reduction in rate of spread, flame length, and crown fire activity in the project area. However, because treatments are smaller than in Alternatives 2 & 3, this Alternative would be less effective in achieving desired conditions. Most notably, rates of spread and flame lengths in the Reds Meadow resort vicinity would be higher than in the proposed alternative. References Agee, JK, CN Skinner Basic principles of forest fuel reduction treatments. Forest Ecology and Management. 211: Agee, JK Fire behavior and fire-resilient forests. I S. Fitzgerald [ed], Fire in Oregon s forests: risk, effects, and treatment options. Portland, OR: Oregon Forest Resources Institute, Brittain, S Fire Family Plus (Version 4.0.2). [Software]. Available from Brown, PM, WD Shepperd, SA Mata, DL McClain Longevity of windthrown logs in a subalpine forest of central Colorado. Canadian Journal of Forestry Research 28: Caprio, AC, M Keifer, K Webster Long-term effects of the 1992 Rainbow Fire, Devils Postpile National Monument, California. Third International Fire Ecology and Management Congress, Association for Fire Ecology, Nov , 2006, San Diego, CA, 6 p. (extended abstract). Dinkey Collaborative Group Dinkey collaborative landscape restoration strategy. [Online]. Available: SouthernSierraNevada/ Dinkey/DK-Strategy.pdf [2012, April 30]. Finney, M, S Brittain, R Seli FlamMap (Version 3.0.0). [Software]. Available from Finney, M An overview of FlamMap fire modeling capabilities. In PL Andrews and BW Butler [comps], Fuel management how to measure success: conference proceedings March 2006; Portland, OR. Proceedings RMRS-P-41. Fort Collins, CO: US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Graham, RT, S McCaffrey, TB Jain, [eds] Science basis for changing forest structure to modify wildfire behavior and severity. Gen. Tech. Rep. RMRS-GTR-120. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. Hann, W, A Shlisky, D Havlina, K Schon, S Barrett, T DeMeo, K Pohl, J Menakis, D Hamilton, J Jones, M Levesque, C Frame Interagency Fire Regime Condition Class Guidebook, Ver. 3. National Interagency Fuels, Fire, & Vegetation Technology Transfer. 15

17 LANDFIRE. U.S. Department of the Interior, Geological Survey. [Online]. Available: [2012, April 30]. North, M, P Stine, K O Hara, W Zielinski, S Stephens An ecosystem management strategy for Sierran mixed-conifer forests. General Technical Report PSW-GTR-220. North, M Managing Sierra Nevada Forests. General Technical Report PSW-GTR-237. Peterson, DL, MC Johnson, C Morris, JK Agee, TB Jain, D McKenzie, ED Reinhardt Forest structure and fire hazard in dry forests of the Western United States. PNW-GTR-628. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 30p. PRISM Climate Group, Oregon State University, April R Development Core Team R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. ISBN Available at: Safford, HD, DA Schmidt, CH Carlson Effects of fuel treatments on fire severity in an area of wildland urban interface, Angora Fire, Lake Tahoe Basin, California. Forest Ecology and Management 258: Safford, HD, K van de Water, D Schmidt California Fire Return Interval Departure (FRID) map, 2010 version. USDA Forest Service, Pacific Southwest Region and The Nature Conservancy-California. URL: Schmidt, DA, AH Taylor, CN Skinner The influence of fuels treatment and landscape arrangement on simulated fire behavior, Southern Cascade range, California. Forest Ecology and Management 255: Scott, JH, RE Burgan Standard fire behavior fuel models: a comprehensive set for use with Rothermel's surface fire spread model. Gen. Tech. Rep. RMRS-GTR-153. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. Stratton, RD Guidance on spatial wildland fire analysis: models, tools, and techniques. Gen. Tech. Rep. RMRS-GTR-183. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. USDA Forest Service Sierra Nevada Forest Plan Amendment. Final Supplemental Environmental Impact Statement, Record of Decision. Van Wagtendonk, JW, JA Fites-Kaufman Sierra Nevada Bioregion. In NG Sugihara, JW Van Wagtendonk, KEShaffer, J Fites-Kaufman and AE Thode, [eds]. Fire in California ecosystems. University of California Press. 16

18 Figure 1. Major flow paths and burn probabilities in Reds Meadow in 2012, following blowdown event. 17

19 Figure 2a. Differences between alternatives in predicted flame length at S end of project area. 18

20 Figure 2b. Differences between alternatives in predicted flame length at N end of project area. 19

21 Figure 3a. Differences between alternatives in predicted rate of spread at S end of project area. 20

22 Figure 3b. Differences between alternatives in predicted rate of spread at N end of project area. 21