Twomile Ecological Restoration Project Fire & Fuels Analysis Anna Payne, Mi-Wok District Fuels Specialist February 2012
1. Introduction
Background In March 2008, the Clavey River Ecosystem Project (CREP) released an assessment of the entire Clavey River watershed that defined existing and desired conditions for water/riparian, fire/fuels, vegetation, wildlife, recreation, roads/trails and socio-economic elements. The following fire/fuels desired conditions from CREP have been incorporated in this project:
Fire benefits key ecosystem components and minimizes risk to resources and human infrastructure; and, Wildfires burn primarily as surface fires with patchy torching of individual trees or patches of trees to reflect natural conditions.
Forest Plan Direction The Stanislaus National Forest ―Forest Plan Direction‖ presents the current Forest Plan management direction (USDA 2010) based on the original Forest Plan as modified through the Forest Plan appeals and amendment processes. Fire and fuels management goals include both reducing threats to communities and wildlife habitat from large, severe wildfires and re-introducing fire into fire-adapted ecosystems. Wildland Urban Intermix (WUI) exists within the project area, 241 acres in the defense zone and 1,214 acres in threat zone (USDA 2010, page 189-190). Broad-scale goals include…managing hazardous fuels…with strategic placement of fuels treatments across broad landscapes to modify wildland fire behavior (USDA 2010, page 13). The Forest Plan Direction includes standards and guidelines for fuels management, activity fuels, fuelbreaks, and plantations (USDA 2010, page 35-39). The fire and fuels objectives listed below concur with Forest Plan Direction.
Strategically place treatment areas across the landscape to facilitate the re-introduction of fire, as well as interrupt fire spread and reduce the size and severity of wildfires. Under 90th percentile fire weather conditions, average a 4-foot flame length. Decrease surface and ladder fuels to meet fire behavior objectives (fire intensity , rate of spread, crown fire potential, and mortality in dominant/co-dominant trees) under 90th percentile weather conditions at a minimum, with treatment being effective for a period of at least 10 years. Treat ridge tops and upper 1/3 of the slope to break up large expanses of continuous fuels, increase suppression opportunities, and provide pre-existing control points for prescribed fire and fire management activities.
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The Twomile Analysis Area The Twomile analysis area is located on the Mi-Wok Ranger District and Groveland Ranger District of the Stanislaus National Forest, within the central portion of the Clavey River watershed, encompassing portions of the Hull Creek, Twomile Creek, Clavey River, and Reed Creek drainages. The project area stretches from the Cottonwood Road to just north of Forest Road 3N01. Treatment activities are proposed on approximately 7,760 acres of the 18,300-acre analysis area.
The project lies entirely within Tuolumne County. The Twomile analysis area comprises 18% of the Clavey River watershed and a review of the area revealed that the existing fuels, vegetation, wildlife habitat and forest product conditions were similar to those identified for the larger Clavey River watershed. As a result, the following fire/fuels management goals were identified:
Provide for the re-introduction of fire (prescribed fire and/or wildfire managed to achieve multiple objectives); Design treatments to re-establish fuel profiles or vegetative conditions more characteristic of historic fire regimes1, eventually allowing fire to function as a natural process; Provide locations and fuel conditions to facilitate safe and effective fire management activities; and, Strategically place landscape area treatments (SPLATS) to interrupt wildfire spread.
Twomile Ecological Restoration Project Summaries This section introduces each of the six Twomile Ecological Restoration projects. The projects are: (A) Vegetation Management, (B) Noxious Weed Control (Dyers Woad Eradication), (C) Great Grey Owl Habitat Improvement, (D) Meadow Restoration, (E) Soil Improvement, and (F) Motorized Trails. Project A: Vegetation Management Analysis Type and Project Number - Environmental Assessment - 30525
Purpose and Need The proposed action is intended to modify vegetation within treatment units to meet desired surface, ladder and crown fuel conditions as well as to attain stand densities necessary for healthy forests during drought conditions utilizing the Pacific Southwest Research Station’s General Technical Report (North, et al. 2009) ―An Ecosystem Management Strategy for Sierran Mixed-Conifer Forests‖ (PSW-GTR-220) as a guideline. The strategy described in this report is compatible with current landscape fuel treatments (i.e., SPLATS (strategically placed area treatments based on the premise that disconnected fuel treatments overlapping across the general direction of the fire spread are theoretically effective in changing fire spread) and Wildland Urban Intermix [WUI] zones) but strives to incorporate ecological restoration and wildlife habitat needs that have not been explicitly addressed. Some important facets of the strategy include mechanical fuels management, ecological importance of fire, and treatments focused on affecting fire behavior (PSW-GTR-220).
The purpose of this project is to improve fire and fuels conditions, forest health and resiliency, and hardwood and wildlife habitat in a manner that provides socio-economic benefits. Forest stands have increased in density and experienced shifts in species composition from shade intolerant pine and hardwood species to shade tolerant conifer species (fir and cedar).
1 A natural fire regime is a general classification of the role fire would play across a landscape in the absence of modern human mechanical intervention, but including the influence of aboriginal burning (Agee 1993).
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These changes in forest structure have altered the role of fire on the landscape, creating unsafe and ineffective fire management conditions, diminished forest health and integrity, and degraded old forest wildlife species habitat. The desired conditions are as follows:
1. Surface, ladder, and crown fuel conditions allow fire to function as a natural process. 2. Strategically placed fuel conditions that facilitate safe and effective fire management activities. 3. Stand densities necessary for healthy and resilient forests during drought conditions. 4. Stands with a greater component of pine and hardwood species. 5. Increased forest heterogeneity with improved hardwood and wildlife habitat components. 6. Cost-effective treatments that produce forest products. 7. Retention/improvement of meadow habitat.
Proposed Action (Alternative 1) Treatments would include varying combinations of thinning, biomass removal, shredding, prescribed fire, and herbicides throughout 7,700 acres of the overall Twomile analyis area (i.e. near Hull Creek, Twomile Creek, and the Clavey River). Road reconstruction (26.0 miles) or maintenance (60.7 miles) would occur on roads, as needed, in support of treatment activities. Additional road management treatments would consist of temporary roads (1.8 miles), reopening then closing (3.0 miles), and reopening then gating (0.3 miles).
No Action (Alternative 2) Under this alternative, no treatments would occur.
Non-Commercial Alternative (Alternative 3) Treatment units proposed would remain the same as the Proposed Action; however, in Alternative 3 those units proposed for commercial thinning would have only material necessary to meet fuels objectives removed. In general, this would result in a 12-inch maximum diameter limit for removal; however, in order to facilitate equipment access to treat the units effectively, there could be circumstances where larger than 12-inch trees would be removed.
Project B: Noxious Weed Control (Dyers Woad Eradication) Analysis Type and Project Number - Environmental Assessment - 34045
Purpose and Need The purpose of this project is to eradicate the only known infestation of dyers woad (Isatis tinctoria) on the Stanislaus National Forest as well as an infestation of perennial sweetpea (Lathyrus latifolia). The infestations are located on 10.3 acres of steep rocky soil near Reed Creek where they could potentially spread downstream into the Clavey and Tuolumne Rivers, and have persisted for more than a decade despite annual hand pulling. The desired condition is to contain or reduce, where possible, the spread of noxious weed infestations on National Forest System lands.
Proposed Action Hand pull and dig infestations of dyers woad and perennial sweetpea on 10.3 acres near Reed Creek. On approximately five of those acres, the herbicide glyphosate will be used in addition to hand pulling and digging.
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Project C: Great Gray Owl Habitat Improvement Analysis Type and Project Number - Categorical Exclusion - 34047
Purpose and Need The purpose of this project is to improve great gray owl breeding habitat near Fahey and Wolfin Meadows. Forested stands adjacent to these meadows lack adequate nesting structures, which is an important limiting factor for this species. The desired condition is to provide suitable breeding habitat to improve the viability of this Region 5 Forest Service sensitive and California State Endangered species across its range in the central Sierra Nevada.
Proposed Action Create two to three nesting structures in forested stands adjacent to Fahey and Wolfin Meadows.
Project D: Meadow Restoration Analysis Type and Project Number - Categorical Exclusion - 34043
Purpose and Need The purpose of this project is to improve the hydrologic function of the following meadows: Wolfin Meadow – Main, Wolfin Meadow – North, Upper Fahey Meadow – South, Lower Fahey Meadow, and the 2N55 Meadow. The existing conditions within these five meadows and their associated streams are eroded banks, headcuts, depressed water tables, encroaching conifers and brush, and poor non-native vegetative cover. The desired condition is improved hydrologic function in meadows to provide crucial wildlife habitat, flood attenuations, and improved water and watershed quality within the Clavey Watershed (a Forest Service designated critical Aquatic Refuge).
Proposed Action Treatments include stabilizing banks and headcuts, revegetation with native species, removal of encroaching brush and trees, and subsoiling compacted areas at the aforementioned meadows.
Project E: Soil Windrow Improvement Analysis Type and Project Number - Categorical Exclusion - 34075
Purpose and Need The purpose of this project is to improve soil productivity in the old Wrights Creek Burn plantation. A substantial amount of topsoil is displaced into windrows on relatively thin volcanic soils, reducing soil nutrient availability. The desired condition is improved soil productivity in areas where vegetation is managed.
Proposed Action Push apart windrows to redistribute displaced topsoil on approximately 24 acres of volcanic soils at the old Wrights Creek Burn plantation west of Funks Meadow and adjacent to Forest Road 3N07.
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Project F: Motorized Trails Analysis Type and Project Number - Categorical Exclusion - 33890
Purpose and Need The purpose of this project is to improve off-highway vehicle (OHV) recreational opportunities and traffic flow, while reducing potential impacts of OHV use to sensitive resources. The existing condition includes public use of NFTS routes located in sensitive areas and poorly located route intersections. The desired condition is a safe OHV trail system that avoids sensitive resources and minimizes conflicts with non-motorized recreation.
Proposed Action Close and restore unauthorized and rerouted trails; construct a combined use bypass trial along 3N01; reroute and bypass NFTS trail segments; install traffic control barriers; and, designate a rock barrier source. Work encompasses various areas near Hull Creek, Twomile Creek, and the Clavey River.
Field Data Collection and Analysis This analysis evaluates the direct, indirect, and cumulative effects of the Alternatives proposed to meet the purpose and need of the Twomile Vegetation Management Project as well as the No Action Alternative, as they relate to fire and fuels. Vegetation, crown, and surface fuel data were collected in 2009 & 2010 utilizing the Common Stand Exam protocol. The stand data was processed and formatted so it could be utilized in the Forest Vegetation Simulator (FVS) program to create tree lists files. Files were then imported into Fire Management Analyst (FMA+) for the units where one fuel model best represented the unit and Behave Plus 5.0.2 was used for the units where two fuel models best represented the unit (due to surface fuel diversity two fuel models were utilized to show fire behavior range) to determine potential site-specific fire behavior for a point in time and space. The outputs of this modeling were utilized to compare the Proposed Action to the No Action alternative. The potential fire behavior was predicted on the landscape using Fire Behavior Assessment Tool (FBAT) which provides an interface between ArcMap and FlamMap3 (Finney and others 2006), a fire behavior mapping and analysis program that computes potential fire behavior characteristics (flame length, rate of spread, fire type or crown fire activity [CFA], and fireline intensity) at a pixel level. The potential fire behavior over the landscape was analyzed using constant 90th percentile weather and fuel moisture conditions based on Mt. Elizabeth Remote Automated Weather System.
2. Affected Environment
The forest structure and species composition in the Twomile analysis area have been altered through fire exclusion and past harvesting practices. Changes include an increase in tree density and structure, shift in tree species (increase in shade tolerant, fire intolerant), and an accumulation of ladder and dead fuels.
Fuel Profile The Twomile planning area consists of natural mixed conifer and ponderosa pine stands, pine plantations, areas dominated by shrub and brush components, and a combination of all of these. Fuel models, fuel loading2, and canopy base heights (CBH)3 were determined through fuels inventory data, stand exams, and FVS.
2 Fuel loading is the amount of live and dead fuel, expressed in weight per unit area (kg/m2 or tons/acre). Total fuel is all fuel, both living and dead, present on a site. Fuel loadings are usually grouped by particle size class. 3 Canopy base height is the lowest height at which there is a sufficient amount of canopy fuel to spread fire into the canopy. The higher the CBH, the lower the risk of passive crown fire (torching) occurring.
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The canopy base heights in the treatment units range from 0 – 30+ feet with an average of 13 feet. Surface fuels were determined using two Photo series books: Quantifying Natural Forest Residues: Southern Cascades, Northern Sierra Nevada - PSW-56 (Blonski, K et al., 1981), and Pacific Northwest - PNW-105 (Maxwell, W et al., 1980).
The inventories show a fuel loading range of 3 to 47 tons per acre with an average of 12 tons per acre (table 1). The 0-3‖ fuels classes are particularly important to predict fire behavior since they are the primary carrier of surface fire and correlate with flame length. The larger fuel classes 3‖ - 20‖ dbh, litter, and duff depth affect residence time and fireline intensity creating a concern during prescribed and wildland fires. Detailed fuels inventory data and methodology is located in the appendix of this report.
Table 1: Average: tons per acre (t/a) and CBH, Litter, Duff 0"-3" t/a 3"-20" t/a Total (t/a) CBH (ft) Litter Depth (in) Duff Depth (in) 4 6 12 13 .1 – 7” .2 – 5”
The proposed units have been assigned a fuel model utilizing the Fire Behavior Prediction Fuel Models (Scott & Burgan 2005) and Aids to Determining Fuel Models for Estimating Fire Behavior (Anderson, Hal E., 1982) documents that characterize areas by fuel type, fuel loading, fuel depth, and fuel arrangement. The fuel models are grouped by fire-carrying fuel type (see figure 1) with the representative fuel models within the project area and approximate acres.
Fuel Type Acres Fuel Model Description
Grass 7 GS2 Mixture of grass and shrub with up to about 50 Shrub percent shrub coverage
Shrub 1,493 SH2, SH3 SH5, FM5 Shrubs cover at least 50% of the site
Timber 5,333 TU1, TU2 TU5, FM8 Grass and shrubs mixed with litter from forest canopy Understory FM9, FM10
Timber 736 TL7, TL8, TL9 Dead and down woody fuel beneath a forest Litter canopy
Slash 112 SB2 Activity fuel or debris
Figure 1: Fuel Types in the Twomile Treatment Units
Fire Behavior Fire behavior and severity depend on the properties of the various fuel (live and dead) strata and the continuity of the fuel strata horizontally and vertically. Existing fire behavior conditions throughout the landscape predict surface and passive crown fire (see figure 2). Current site-specific fire behavior condition within the units predict passive crown fire behavior on 3,317 acres. Predicted site-specific fire behavior by unit is listed in table 6. There are two stages to the crown fire process: the initiation of crown fire activity, known as ―torching‖ (passive), and the process of active crown fire spread, where fire moves from tree crown to tree crown (Van Wagner 1977).
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. A surface (green) fire consumes surface fuels on the forest floor, fire is not likely to ignite the tree crown, and modeling is the same as Behave Plus.
. A passive (yellow) crown fire involves individual trees or groups of trees torching out as fire spreads through surface fuels.
. Active (red) crown fire involves the entire fuel complex, but the crowning phase remains dependent on heat released from the surface fuels for continued spread.
The predicted fire behavior represents the expected values if a fire were to burn through the area in its existing condition. In any particular area, you could have a range of fire behavior characteristics that are dependent on fuels, weather, and topography. The fire hazard for any particular forest stand or landscape can be characterized by the potential for the fuels to cause specific types of fire behavior and effects (Graham and others 2004).
In fire modeling, the fire environment is the characteristics of a site that influence fire behavior described by surface and canopy fuel characteristics, windspeed and direction, relative humidity, and slope steepness. Fuel, topography, and weather interact to create particular fire intensity (energy release, flame length, rate of spread) and severity (damage to the forest overstory and associated changes in resource values).
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The stands with a combination of heavy continuous fuels and a closed canopy (interlocking of crowns) create the potential for initiation and sustainability of crown fire. Throughout most of the landscape the predicted flame lengths are over four feet (see figure 3). Under current fuel conditions with flame lengths over four feet, fires are too intense for fire suppression personnel at the head of the fire using hand tools. Suppression effectiveness is expressed by flame length (resistance to control). Predicted flame lengths by unit range from 1-13 feet with an average of six feet and fireline intensity ranges from 6 - 1570 Btu/ft/sec with an average of 412 Btu/ft/sec. Predicted rate of spread by unit ranges from 1-46 chains per hour with an average of 12 chains per hour. A narrative interpretation of resistance to control based on flame length and fireline intensity is found in Table 2.
Table 2: Resistance to Control Interpretation
Flame Fireline Length Intensity Interpretations (ft) (Btu/ft/s) Persons using hand tools can generally attack fires at the head or flanks. Under 4 (green) Under 100 Hand line should hold the fire. Fires are too intense for direct attack on the head by persons using hand 4-8 (yellow) 100-500 tools. Hand line cannot be relied on to hold the fire. Equipment such as dozers, engines, and retardant aircraft can be effective. Fires may present serious control problems - torching out, crowning, and 8-11 (orange) 500-1000 spotting. Control efforts at the fire head would probably be ineffective. Crowning, spotting, and major fire runs are probable. Control efforts at Over 11 (red) Over 1000 head of fire are ineffective.
Fire History In mixed conifer forest types, surface fires occur generally between 5-10 years, with mixed severity fires occur about every 50 years. Overall fire regime for the project area is I: 0-35-year frequency of low and mixed severity. Fire history analysis area extends one mile outside the project area to illustrate fires that could have potentially threatened the project area.
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Fires (red outline) within the analysis area are displayed. In years 1912-2010, nineteen fires (six acres or larger) have burned over 35,000 acres within the analysis area (table 3). One hundred ten fires (five acres and smaller) have burned 25 acres between 1970 and 2010 (a period when fire records are more dependable). Fire history surrounding the area shows large conflagrations (blue outline) have occurred (see figure 4) in forest types similar to those in the Twomile analysis area. These fires involved active crown fire behavior over large areas, resulting in stand replacing events. These areas now consist of even aged pine plantations.
In 1950, the Wright’s Creek fire burned over 24,000 acres, in 1973, the Granite fire burned over 16,000 acres, in 1987, the Paper fire burned over 45,000 acres, and in 1996, the Rogge fire burned over 20,000 acres
Table 3: Fire History (six acres and larger) within Analysis Area Year Acres Fire Name 1912 797 1913 341 1917 363 1919 5,339 1920 219 1920 171 1921 487 1925 128 1928 505 1945 544 1950 24,349 Wright's Creek 1957 10 Clavey 1960 2,116 Flora 1960 6 1971 15 Thompson 1996 16 Two Mile 1996 21 25 Mile 2000 41 Camp 2008 11 Clavey 35,479 total acres Nineteen fires
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Weather The weather patterns in the Twomile analysis that influence fire behavior are typical of west-side Sierra foothills. The predominant wind pattern is from the southwest, although strong north winds may develop in association with frontal passages, especially in the spring and fall. Average annual precipitation is 35-45 inches, falling as rain and snow, primarily between October and April. The mountainous terrain causes frequent cumulus cloud development during spring, summer, and fall, often producing lightning. Summer rain can occur occasionally, although usually in the form of brief scattered showers accompanied by lightning. The Fire Family Plus program was used to determine 90th percentile weather conditions based on data collected from the Mt. Elizabeth Weather Station during 1973 – 2009 (May 1 – Oct. 31). See Table 4, which represents of a typical hot, dry summer day, but not the worst-case scenario.
Table 4: Mt. Elizabeth 90th Percentile Weather Data Weather Temperature Relative 1 Hour 10 Hour 100 1000 Herbaceous Woody 20’ Percentiles ( F) Humidity Fuels Fuels Hour Hour Fuels Fuels Windspeed (%) Moisture Moisture Fuels Fuels Moisture Moisture (miles per (%) (%) Moisture Moisture (%) (%) hour) (%) (%) 90 88 14 3 4 5 7 3 70 10 (4933’ elevation; May 1-Oct.31, 1973-2009)
Values at Risk Ember production from torching trees and crown fire can rapidly advance the fire front, increasing its growth and allowing it to cross natural or artificial barriers (Albini 1979). Spotting distance based on 90th percentile weather conditions within the analysis area is 0.2 miles with a Probability of Ignition4 (PI) of 86%. Within the vicinity of the project area, the following could be affected by wildland fires that originate within or adjacent to the analysis area:
. Residences, . Clavey River watershed, . Archeological sites, . Northern Goshawk and Spotted Owl Protected Activity Centers (PAC), Spotted Owl Home Range Core Area (HRCA), . Old Forest Emphasis Area (OFEA), General Forest, . Critical Aquatic Refuge (CAR), and . Plantations.
4 The probability of ignition is an indication of the chance that a firebrand will cause an ignition. The calculation is based on shading of fuels from sun, 1-hour fuel moisture, and dry bulb temperature.
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3. Environmental Consequences
Alternative 1 Proposed Action Alternative 1 proposes treatment activities to achieve desired conditions for the analysis area and meet the defined purpose and need. This alternative proposes to treat approximately 7,700 acres of the 18,300-acre planning area. Proposed activities are listed in table 5 and detailed in the fuels appendix. A map of treatment units for the proposed action is provided in the Environmental Analysis document.
The treatments proposed and the effects analyzed attempt to measure the combination and balance of reducing excessive fuel loading to reduce wildland fire effects, the ability to re-introduce fire into the ecosystem by prescribed fire and managed wildland fire, and maintaining the importance of variable forest structure and fuels conditions for ecological restoration and forest resilience. A common element in the units is the use of prescribed fire both as a fuel treatment and as a tool for restoring natural processes. Fire is both a viable fuel-treatment tool and an important jumpstart for many ecosystems processes stalled by accumulating surface fuels and the absence of frequent burning (PSW-GTR-220).
In the fuel reduction prescriptions, the proposed activity is designed to remove surface (natural and activity slash) and ladder fuels (brush and small trees less than 10 dbh) to meet fire behavior objectives (decrease in flame length, fire intensity, rate of spread, crown fire potential). Mechanical treatment of fuels can allow fire, both wildland and prescribed fire to be used as a management tool. Consequently, treatments would create varying stand density and structure influenced by aspect, slope position, site productivity, tree species, and unusual micro‐site conditions. After thinning and biomass treatments have been completed, shredding opportunities would be evaluated by the fuels officer to see if needed to meet fuels objectives and/or as a maintenance tool when prescribed fire is not possible. Detailed prescriptions and treatments by unit are located in the fuels appendix.
Prescriptions and Design Elements There are multiple prescriptions within each unit. In choosing among the options for type, intensity, size, and placement/pattern of fuel treatments across a landscape, there are multiple objectives identified within the units, fuels management needs may not always be attained. As for funding constraints, particularly regarding fuel treatments in remote and inaccessible areas, prescribed burning and managed wildland fire may be the most appropriate alternatives (Mills 2006, Collins et al. 2007). Protected Activity Centers (PACs) were avoided except in strategic areas and/or where prescribed fire and handcut treatments would reduce surface and ladder fuels. Treatments overlap in several areas; this causes a situation where treatments acres are greater than total acres. The prescriptions and activities are listed in table 5. See treatment summary in the Environmental Analysis document.
Table 5: Prescriptions and Activities Prescription # of units/ Proposed Activities acres Fuels Reduction – 10/614 Reduce brush, small trees and dead and down fuels Defense and Threat Zone Thin overstory to 40% -50% canopy cover
Fuels Reduction 38/1,180 Reduce brush, small trees and dead and down fuels
Fuels Reduction - 6/188 Reduce brush, small trees and dead and down fuels Fuelbreak Herbicides to maintain brush reduction
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Shaded Fuelbreak 17/2,308 Thin overstory so trees are a minimum of a crown-width apart. Remove all biomass conifers
Top 1/3 slope 26/2,025 Retain 50% canopy cover in majority of unit Thin to favor pine and oak Remove all biomass
Fisher Emphasis 9/544 Retain 50% canopy cover and 50% biomass in clumpy Restoration arrangement Thin to favor pine and oak
Fisher Emphasis 8/507 Retain 60% canopy cover and 50% biomass in clumpy Maintenance arrangement. Thin to favor pine and oak
Pine and Oak Restoration 14/583 Retain 50% canopy cover and 50% biomass in clumpy arrangement. Thin to favor pine and oak Create openings to regenerate pine
Pine & Oak Retention 5/348 Retain 50% canopy cover & 50% biomass in clump arrangement Thin to favor oak and retain existing high levels of pine Openings 7/456 Create openings to regenerate pine (to be reforested with ponderosa and sugar pine seedlings)
Oak Restoration/Pine 16/1,611 Thin pines to levels that would retain stand density index Density Management below 230 for 20 years Create openings around existing oaks
Meadow Encroachment 2/16 Handcut/pile/burn conifers encroaching on meadows
Within the planning area, proposing treatment units was not practical in some areas due to the combination of steep slopes, poor feasibility to be able to treat, and inaccessibility. This reduced the ability to modify potential fire behavior, especially crown fire index5 in some areas.
The proposed treatment design elements (table 6) and descriptions for fuels management include criteria to implement the projects to meet desired conditions.
5Crown fire index is the windspeed at which fire will move from tree crown to tree crown resulting in active crown fire.
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Table 6: Twomile Design Element Table List of Design Project Project Project Project Project Project Project Elements A1 – A3 - B – C – D – E – Soil F – Vegetation Vegetation Noxious Great Meadow Windrow Motorized Management Management Weed Grey Owl Restoration Improvement Trail (Proposed (Non- Control Habitat Action) Commercial Alternative) Fuels #1 – x x x Air Quality Fuels #2 – Thinning/Biomass x x Removal Fuels #3 – Monitoring/ x x Maintenance Fuels #4 – Natural/Activity x x Slash Fuels #5 – Prescribed Fire/Pile x x x Burning Fuels #6 – x x Shredding/Handcut
Design Elements Treatments overlap in several areas; this causes a situation where treatments acres are greater than total acres.
Air Quality: All burning activities would adhere to pertinent air quality regulations. The pile and burn method increases the dispersion of smoke by decreasing the amount of fuel that is burned at any one time. If smoke or weather conditions become adverse, the piles can easily be extinguished. Burning would be conducted during meteorological periods favorable to smoke dispersion.
Thinning: Activity is proposed on 5,595 acres. Thinning treatments in natural stands would consist of harvesting trees using the PSW-GTR-220 as a guide. Emphasis would be placed on thinning out existing patches of trees to meet the fuels, density, wildlife, and/or species composition objectives that pertain to each unit. The majority of the trees removed would be in the understory, in the suppressed and intermediate crown classes. Thinning in plantations would consist of harvesting merchantable and submerchantable trees to reduce crown continuity and increase species diversity. A variety of spacing prescriptions will be employed to decrease the probability of crown fire initiation and spread, increase stand heterogeneity and accelerate the development of large trees, while keeping stand densities below the threshold for increased susceptibility to drought and insect related mortality for a period of 20 years.
Pre-commercial Thinning: Pre-commercial thinning is proposed on 112 acres. Trees less than 12‖ dbh would be removed following thinning design elements.
Biomass Removal: Activity is proposed on 5,458 acres. Remove trees (4 - 10‖ dbh) that provide a ladder to larger trees; reducing the potential for torching and creating conditions suitable for prescribed fire. The biomass treatments would be conducted at the same time as the thinning treatments. Hand thinning and pruning will be used to accomplish this removal where the use of mechanical treatments is not feasible or desirable due to other resource concerns. Within PACs, hand thinning is limited to trees less than 6‖ DBH.
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Monitoring/Maintenance: Post treatment evaluations of site-specific fuels conditions over the project area would be completed to determine the need for follow-up treatment. Maintenance schedules would be designed to meet long-term fuels reduction objectives. Units would be monitored and evaluated to determine what method would best meet desired condition. Maintenance would comply with NEPA requirements.
Natural/Activity Slash: Treat natural and activity fuels to reduce fuel loading, flame length and fire intensity levels (resistance-to-control) to desired conditions by hand‐piling, dozer‐piling, prescribed fire, and pile burning. Prior to prescribed fire, dozer piling is proposed where heavy concentrations of dead and down fuel exist to minimize fire effects.
Prescribed Fire/Pile Burning: Pile and/or prescribed fire is proposed on 7,670 acres. Prescribed fire would re-introduce fire on the landscape and, along with pile burning, remove residual logging slash after harvest operations are complete. Post- thinning and prior to burning, fuel loading is increased on the ground and/or in piles. Fire behavior in these areas can be moderate; however, most of the ladder fuels have been removed which decreases the chance of crown fire initiation. Budget, resource availability, air quality, and burn windows influence timing of follow-up treatment. Adjacent to residences, piling within 100’ is required by the contractor. After the piles are created, lined, and covered, we prefer the piles to "cure" or dry out to allow for effective consumption of the fuels. This can take up to approximately 6-9 months depending on when the piles were built and the size of the material thinned. Once the piles are ready, they would be burned by trained fire crews. In preparation for burning, perimeter line construction will be needed where roads, trails, or natural barriers are absent. This would involve hand cutting and pruning of vegetation including trees up to 6-inch diameter and scraping to bare mineral soil. All firelines follow the established guidelines as outlined in the Best Management Practices (BMP’s). Snags would be felled that are a safety issue and/or threat to control lines and cultural resources.
Upon completion of burning, the firelines that intersect roads, trails, etc would be disguised by pine needles, brush, etc to reduce the likelihood of firelines becoming trails. Mortality would be less than 10- 20% in the larger trees (minimum 14‖ dbh) to maintain stand structure and contribute to future habitat diversity. Mortality in the smaller trees (4-13‖ dbh) would be less than 20% to maintain stand structure and contribute to future habitat diversity. Maintain discontinuous shrub patches wherever possible while meeting fuels objectives. Burning would be in all seasons following strict prescriptions and mitigations outlined in the burn plan. In most areas, initial entry would be in the spring when fuel moistures are at their highest. Multiple entries would be needed to meet objectives.
Shredding/Handcut: Activity is proposed on 5,379 acres. Shredding consists of removing brush and small trees up to 6‖ DBH. Hand cutting consists of thinning small trees and brush in units that are not feasible for machinery to operate in and pruning residual trees. Maintain discontinuous shrub patches wherever possible while meeting fuels objectives. Some units may require isolated thinning to reduce vertical fuels encroachment that, would in turn, reduce tree mortality during prescribed fire. Within PACs, hand thinning is limited to trees less than 6‖ DBH.
Herbicide: Activity is proposed on 188 acres. Fuelbreaks have been identified as containing re-sprouting species of brush that are present in levels that cannot be treated and maintained efficiently and effectively by hand or mechanical means. Herbicides were identified as being essential to control this re-sprouting brush. The prescription proposed is to shred or hand cut the brush, then use hand applications of the herbicide glyphosate to control the re-sprouting brush. The re-sprouting brush would be treated annually for up to 5 years, as needed to maintain the brush at acceptable fuels conditions. Only re-sprouting brush species would be targeted in the herbicide applications.
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Direct Effects Alternative 1 would meet desired conditions for fire and fuels management where wildfires burn primarily as surface fires with patchy torching of individual trees or patches of trees (i.e., passive fire type). Units in bold type could experience additional torching post treatment due to ladder fuels (biomass in clumps). Flame length pre-treatment is 1-13 feet, post treatment 1-4 feet. Fireline intensity (Btu/ft/sec) pre-treatment is 6 - 1570, post treatment 2-144. The canopy base height pre-treatment is 0-47 feet, post- treatment 4-65 feet. Rate of spread chains/hour (chain is 66 feet) pre-treatment is 1-53, post-treatment 1-6 chains/hour. Site-specific fire behavior for each unit is displayed in table 7.
Table 7: Fire behavior by unit Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) D03 & D03P No Action 8, TU5 6 Passive 7 418 8 D03 Alt 1 TU1, SH2 22 Surface 4 144 4 D03 Alt 3 TU1, SH2 12 Surface 4 144 4 D04 No Action 10, TL7 6 Passive 5 190 5 D04 Alt 1 TL1, SH2 6 Surface 4 144 3 D04 Alt 3 TL1, SH2 6 Surface 4 144 3 D05 No Action 8, TL7 6 Surface 1 6 1 D05 Alt 1 TL1 6 Surface 1 2 1 D05 Alt 3 TL1 6 Surface 1 2 1 D06 No Action 10, TL7 10 Surface 5 190 5 D06 Alt 1 TL1, SH2 10 Surface 4 144 3 D06 Alt 3 TL1, SH2 10 Surface 4 144 3 D07No Action 8, TL7 7 Surface 2 26 2 D07 Alt 1 TL1 7 Surface 1 2 1 D07 Alt 3 TL1 7 Surface 1 2 1 D08 No Action 10, SB2 17 Surface 6 247 9 D08 Alt 1 TU1, SH2 17 Surface 4 144 4 D08 Alt 3 TU1, SH2 32 Surface 4 144 4 D09 No Action 10 9 Surface 5 190 7 D09 Alt 1 TU1 9 Surface 2 19 2 D09 Alt 3 TU1 9 Surface 2 19 2 D10 No Action 10, TU5 17 Surface 7 418 7 D10 - Alt 1 TU1 17 Surface 2 19 2 D10 - Alt 3 TU1 19 Surface 2 19 2 D12 No Action 10, TL2 8 Passive 5 190 4 D12 Alt 1 TU1 16 Surface 2 19 2 D12 Alt 3 TU1 16 Surface 2 19 2 D13 No Action 10, TL2 8 Passive 5 190 4 D13 Alt 1 TU1 8 Surface 2 19 2 D13 Alt 3 TU1 16 Surface 2 19 2 D14 No Action SH5 6 Passive 13 1570 46 D14 Alt 1 SH2 6 Surface 4 144 6 D14 Alt 3 SH2 6 Surface 4 144 6 D15 No Action 8, TL2 4 Surface 1 6 1 D15 Alt 1 TU1 6 Surface 2 19 2 D15 Alt 3 TU1 6 Surface 2 19 2 D16 No Action 8, SH5 7 Passive 13 1570 24
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) D16 Alt 1 SH2 7 Surface 4 144 6 D16 Alt 3 SH2 7 Surface 4 144 6 F11 No Action 8 6 Surface 1 6 2 F11 Alt 1 TU1 10 Surface 2 19 2 F11 Alt 3 TU1 10 Surface 2 19 2 F11-1 No Action 8, SH5 6 Passive 13 1570 24 F11-1 Alt 1 SH2 6 Surface 4 144 6 F11-1 Alt 3 SH2 6 Surface 4 144 6 F11-2 No Action 8 6 Surface 1 6 2 F11-2 Alt 1 TU1 6 Surface 2 19 2 F11-2 Alt 3 TU1 6 Surface 2 19 2 F13 No Action 8 46 Surface 1 6 2 F13 Alt 1 TU1 50 Surface 2 19 2 F13 Alt 3 TU1 50 Surface 2 19 2 F14 No Action 8 20 Surface 1 6 2 F14 Alt 1 TU1 53 Surface 2 19 2 F14 Alt 3 TU1 45 Surface 2 19 2 F16-1 No Action 8 1 Surface 1 6 2 F16-1 Alt 1 TU1 12 Surface 2 19 2 F16-1 Alt 3 TU1 65 Surface 2 19 2 F16-2 No Action 5 1 Passive 6 274 20 F16-2 Alt 1 TU1 15 Surface 2 19 2 F16-2 Alt 3 TU1 15 Surface 2 19 2 L01 No Action 10, SH5 16 Passive 13 1570 27 L01 Alt 1 TU1 16 Surface 2 19 2 L01 Alt 3 TU1 16 Surface 2 19 2 L01-F No Action 8, SH5 8 Passive 13 1570 24 L01-F Alt 1 SH2 8 Surface 4 144 6 L01-F Alt 3 SH2 8 Surface 4 144 6 L02 No Action 10, SH5 6 Passive 13 1570 27 L02 Alt 1 SH2 6 Surface 4 144 6 L02 Alt 3 SH2 6 Surface 4 144 6 L02-F No Action 10, TU5 13 Passive 7 418 7 L02-F Alt 1 SH2 13 Surface 4 144 6 L02-F Alt 3 SH2 13 Surface 4 144 6 L02-P No Action 8, TU5 6 Passive 7 418 5 L02-P Alt 1 SH2 6 Surface 4 144 6 L02-P Alt 3 SH2 6 Surface 4 144 6 L05-F No Action SH5 4 Passive 13 1570 46 L05-F Alt 1 SH2 4 Surface 4 144 6 L05-F Alt 3 SH2 4 Surface 4 144 6 L06-1 No Action 8, SB2 15 Surface 6 247 6 L06-1 Alt 1 TU1 15 Surface 2 19 2 L06-1 Alt 3 TU1 55 Surface 2 19 2 L06-2 No Action 8, SB2 15 Surface 6 247 6 L06-2 Alt 1 TU1, SH2 15 Surface 4 144 4 L06-2 Alt 3 TU1, SH2 15 Surface 4 144 4 L08-1 No Action 8 20 Surface 1 6 2
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) L08-1 Alt 1 TU1 20 Surface 2 19 2 L08-1 Alt 3 TU1 20 Surface 2 19 2 L08-3 No Action SH5 4 Passive 13 1570 46 L08-3 Alt 1 SH2 4 Surface 4 144 6 L08-3 Alt 3 SH2 4 Surface 4 144 6 L08-F1 No Action 8, SH5 18 Passive 13 1570 24 L08-F1 Alt 1 SH2 18 Surface 4 144 6 L08-F1 Alt 3 SH2 18 Surface 4 144 6 L08-F2 No Action 10, SH5 22 Passive 13 1570 27 L08-F2 Alt 1 SH2 22 Surface 4 144 6 L08-F2 Alt 3 SH2 22 Surface 4 144 6 L09 No Action 10 6 Passive 5 185 7 L09 Alt 1 TU1 31 Surface 2 19 2 L09 Alt 3 TU1 50 Surface 2 19 2 L10-1 No Action 8, 5 14 Surface 6 274 11 L10-1 Alt 1 TU1 15 Surface 2 19 2 L10-1 Alt 3 TU1 14 Surface 2 19 2 L10-2 No Action 8, 5 14 Surface 6 265 19 L10-2 Alt 1 TU1 15 Surface 2 19 2 L10-2 Alt 3 TU1 14 Surface 2 19 2 L10-F No Action 8, 5 14 Surface 6 265 19 L10-F Alt 1 TU1 14 Surface 2 19 2 L10-F Alt 3 TU1 14 Surface 2 19 2 L11 No Action TL4/TU1 20 Surface 1 10 2 L11 Alt 1 TU1 20 Surface 2 19 2 L11 Alt 3 TU1 20 Surface 2 19 2 L12 No Action 10 20 Surface 5 190 7 L12 Alt 1 SH2 20 Surface 4 144 6 L12 Alt 3 SH2 20 Surface 4 144 6 L12-F No Action 10 2 Passive 5 190 7 L12-F Alt 1 SH2 4 Surface 4 144 6 L12-F Alt 3 SH2 4 Surface 4 144 6 L13 No Action 8, TL7 12 Surface 2 25 2 L13 Alt 1 TU1 28 Surface 2 19 2 L13 Alt 3 TU1 19 Surface 2 19 2 L14 No Action 10, TU5 14 Passive 7 418 7 L14 Alt 1 TU1, SH2 14 Surface 4 144 4 L14 Alt 3 TU1, SH2 14 Surface 4 144 4 L15 No Action 10, SB2 11 Surface 6 247 10 L15 Alt 1 TU1 11 Surface 2 19 2 L15 Alt 3 TU1 11 Surface 2 19 2 L16-F No Action 10 4 Passive 5 190 7 L16-F Alt1 SH2 4 Surface 4 144 6 L16-F Alt 3 SH2 4 Surface 4 144 6 T01-1No Action 10, TU5 10 Passive 7 418 7 T01-1 Alt 1 TU1, SH2 10 Surface 4 144 4 T01-1 Alt 3 TU1, SH2 10 Surface 4 144 4 T01-2 No Action 10, TU5 10 Passive 7 418 7
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) T01-2 Alt 1 TU1, SH2 10 Surface 4 144 4 T01-2 Alt 3 TU1, SH2 10 Surface 4 144 4 T01-3 No Action 10 5 Passive 5 190 7 T01-3 Alt 1 TU1 6 Surface 2 19 2 T01-3 Alt 3 TU1 6 Surface 2 19 2 T01-F1 No Action 10 5 Passive 5 190 7 T01-F1 Alt 1 TU1 5 Surface 2 19 2 T01-F1 Alt 3 TU1 5 Surface 2 19 2 T03-3 No Action 10 3 Passive 5 190 7 T03-3 Alt 1 SH2 4 Surface 4 144 6 T03-3 Alt 3 SH2 4 Surface 4 144 6 T03-F No Action 10 3 Passive 5 185 7 T03-F Alt 1 TU1 7 Surface 2 19 2 T03-F Alt 3 TU1 3 Surface 2 19 2 T04 No Action 10, TU5 16 Surface 7 418 7 T04 Alt 1 TU1 16 Surface 2 19 2 T04 Alt 3 TU1 16 Surface 2 19 2 T06 No Action 10 20 Surface 5 185 7 T06 Alt 1 TU1, SH2 20 Surface 4 144 4 T06 Alt 3 TU1, SH2 20 Surface 4 144 4 T07 No Action 10, TL8 11 Surface 5 190 6 T07 Alt 1 TL1 11 Surface 1 2 1 T07 Alt 3 TL1 11 Surface 1 2 1 T09 No Action 9, SH2 17 Surface 3 47 5 T09 Alt 1 SH2 17 Surface 4 144 6 T09 Alt 3 SH2 17 Surface 4 144 6 T11 No Action 8 17 Surface 1 6 1 T11 Alt 1 TU1 17 Surface 2 19 2 T11 Alt 3 TU1 17 Surface 2 19 2 T12 No Action 10 4 Passive 5 185 7 T12 Alt 1 TU1, SH2 4 Surface 4 144 4 T12 Alt 3 TU1, SH2 4 Surface 4 144 4 T13-1 No Action TU5 11 Passive 7 406 8 T13-1 Alt 1 TU1, SH2 11 Surface 4 144 4 T13-1 Alt 3 TU1, SH2 11 Surface 4 144 4 T13-6 No Action TL4 15 Surface 1 10 2 T13-6 Alt 1 TL1 15 Surface 1 2 1 T13-6 Alt 3 TL1 15 Surface 1 2 1 T13-P1 No Action 10 3 Passive 5 190 7 T13-P1 Alt 1 TU1 6 Surface 2 19 2 T13-P1 Alt 3 TU1 6 Surface 2 19 2 T13-P2 No Action 8, TU5 7 Passive 7 418 5 T13-P2 Alt 1 TU1 7 Surface 2 19 2 T13-P2 Alt 3 TU1 7 Surface 2 19 2 T14 No Action 10, TL7 23 Surface 5 190 5 T14 Alt 1 TU1, SH2 23 Surface 2 19 2 T14 Alt 3 TU1, SH2 23 Surface 2 19 2 T14-1 No Action 10, TL7 14 Surface 5 190 5
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) T14-1 Alt 1 TU1 14 Surface 2 19 2 T14-1 Alt 3 TU1 14 Surface 2 19 2 T14-2 No Action 10, TU5 8 Passive 5 185 7 T14-2 Alt 1 TU1 8 Surface 2 19 2 T14-2 Alt 3 TU1 8 Surface 2 19 2 T15-P No Action 10, TL7 18 Surface 5 190 5 T15-P Alt 1 TU1 18 Surface 2 19 2 T15-P Alt 3 TU1 18 Surface 2 19 2 T19 No Action 8, TU5 12 Passive 7 418 5 T19 Alt 1 TU1, SH2 12 Surface 4 144 4 T19 Alt 3 TU1, SH2 12 Surface 4 144 4 T21-1 No Action 10 7 Passive 5 191 7 T21-1 Alt 1 TU1 7 Surface 2 19 2 T21-1 Alt 3 TU1 7 Surface 2 19 2 T21-2 No Action 10 7 Passive 5 191 7 T21-2 Alt 1 TU1 7 Surface 2 19 2 T21-2 Alt 3 TU1 7 Surface 2 19 2 T22 No Action 5 1 Passive 6 274 20 T22 Alt 1 SH2 4 Surface 4 144 6 T22 Alt 3 SH2 4 Surface 4 144 6 T25-1 No Action 10, SH5 9 Passive 13 1570 27 T25-1 Alt 1 SH2 9 Surface 4 144 6 T25-1 Alt 3 SH2 9 Surface 4 144 6 T25-2 No Action 8, SH5 9 Passive 13 1570 24 T25-2 Alt 1 TU1, SH2 9 Surface 4 144 4 T25-2 Alt 3 TU1, SH2 9 Surface 4 144 4 T27 No Action 8, SH5 7 Passive 13 1570 24 T27 Alt 1 TU1, SH2 7 Surface 4 144 4 T27 Alt 3 TU1, SH2 7 Surface 4 144 4 T35 No Action 10 4 Passive 5 185 7 T35 Alt 1 TU1 4 Surface 2 19 2 T35 Alt 3 TU1 4 Surface 2 19 2 T36 No Action 10, SH5 18 Passive 13 1570 27 T36 Alt 1 TU1 18 Surface 2 19 2 T36 Alt 3 TU1 18 Surface 2 19 2 T40 No Action 10, SH2 4 Passive 5 190 6 T40 Alt 1 TU1 4 Surface 2 19 2 T40 Alt 3 TU1 4 Surface 2 19 2 T43 No Action TL7 20 Surface 2 25 2 T43 Alt 1 TL1 20 Surface 1 2 1 T43 Alt 3 TL1 20 Surface 1 2 1 T45 No Action 8, TL8 17 Surface 3 69 3 T45 Alt 1 TL1 17 Surface 1 2 1 T45 Alt 3 TL1 17 Surface 1 2 1 T46 No Action 8, SH2 13 Surface 4 144 4 T46 Alt 1 TU1 13 Surface 2 19 2 T46 Alt 3 TU1 13 Surface 2 19 2 T47 No Action 5, SH5 2 Passive 13 1570 36
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) T47 Alt 1 SH2 4 Surface 4 144 6 T47 Alt 3 SH2 4 Surface 4 144 6 T48 No Action 8, SH2 13 Surface 4 140 5 T48 Alt 1 SH2 13 Surface 4 144 6 T48 Alt 3 SH2 13 Surface 4 144 6 T49 No Action SH5 20 Surface 13 1570 46 T49 Alt 1 SH2 20 Surface 4 144 6 T49 Alt 3 SH2 20 Surface 4 144 6 T53-P No Action 8, TU5 16 Surface 7 418 5 T53-P Alt 1 TU1 16 Surface 2 19 2 T53-P Alt 3 TU1 16 Surface 2 19 2 TH01 No Action 10, SH5 13 Passive 13 1570 27 TH01Alt 1 SH2 13 Surface 4 144 6 TH01Alt 3 SH2 13 Surface 4 144 6 TH02 No Action 8, SH5 13 Passive 13 1570 24 TH02 Alt 1 SH2 13 Surface 4 144 6 TH02 Alt 3 SH2 13 Surface 4 144 6 TH04 No Action 10, TL8 6 Passive 5 190 6 TH04 Alt 1 TU1 6 Surface 2 19 2 TH04 Alt 3 TU1 6 Surface 2 19 2 TH06 No Action SH5 4 Passive 13 1570 46 TH06 Alt 1 SH2 4 Surface 4 144 6 TH06 Alt 3 SH2 4 Surface 4 144 6 TH07 No Action SH3 4 Surface 2 34 3 TH07 Alt 1 SH2 4 Surface 4 144 6 TH07 Alt 3 SH2 4 Surface 4 144 6 TH08 No Action SH5 10 Passive 13 1535 45 TH08 Alt 1 SH2 10 Surface 4 144 6 TH08 Alt 3 SH2 10 Surface 4 144 6 TH09-1 No Action SH7 17 Surface 5 190 7 TH09-1 Alt 1 SH2 17 Surface 4 144 6 TH09-1 Alt 3 SH2 17 Surface 4 144 6 TH09-2 No Action 10 22 Passive 13 1367 30 TH09-2 Alt 1 SH2 22 Surface 4 144 6 TH09-2 Alt 3 SH2 22 Surface 4 144 6 TH12 No Action SH3 4 Surface 2 34 3 TH12 Alt 1 SH2 4 Surface 4 144 6 TH12 Alt 3 SH2 4 Surface 4 144 6 TH13 No Action SH3 4 Surface 2 34 3 TH13 Alt 1 SH2 4 Surface 4 144 6 TH13 Alt 3 SH2 4 Surface 4 144 6 TH19 No Action SH7 0 Passive 13 1367 30 TH19 Alt 1 SH2 4 Surface 4 144 6 TH19 Alt 3 SH2 4 Surface 4 144 6 TH20 No Action TL4 30 Surface 1 10 2 TH20 Alt 1 TL1 30 Surface 1 2 1 TH20 Alt 3 TL1 30 Surface 1 2 1 TH20-F No Action 8 45 Surface 1 6 1
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) TH20-F Alt 1 TU1 45 Surface 2 19 2 TH20-F Alt 3 TU1 45 Surface 2 19 2 TH21-F No Action TU5 19 Surface 7 406 8 TH21-F Alt 1 TU1 19 Surface 2 19 2 TH21-F Alt 3 TU1 19 Surface 2 19 2 TH23 No Action SH5 10 Passive 13 1535 45 TH23 Alt 1 SH2 10 Surface 4 144 6 TH23 Alt 3 SH2 10 Surface 4 144 6 W01-1 No Action 8, TL7 33 Surface 2 26 2 W01-1 Alt 1 TL1, SH2 33 Surface 4 144 3 W01-1 Alt 3 TL1, SH2 33 Surface 4 144 3 W01-2 No Action TL7 39 Surface 2 26 2 W01-2 Alt 1 TL1 39 Surface 1 2 1 W01-2 Alt 3 TL1 39 Surface 1 2 1 W02 No Action 8, TL5 25 Surface 2 26 2 W02 Alt 1 TU1 25 Surface 2 19 2 W02 Alt 3 TU1 25 Surface 2 19 2 W05-1 No Action 8, TL8 25 Surface 3 69 3 W05-1 Alt 1 TL1 25 Surface 1 2 1 W05-1 Alt 3 TL1 25 Surface 1 2 1 W05-2 No Action 10, TL8 27 Surface 5 190 6 W05-2 Alt 1 TL1, SH2 27 Surface 4 144 3 W05-2 Alt 3 TL1, SH2 27 Surface 4 144 3 W05-M No Action GR3 30 Surface 8 459 53 W05-M Alt 1 GR1 30 Surface 2 23 14 W07 No Action 10 23 Surface 5 190 7 W07 Alt 1 TU1 23 Surface 2 19 2 W07 Alt 3 TU1 23 Surface 2 19 2 W08 No Action 10 6 Passive 5 185 7 W08 Alt 1 TU1 22 Surface 2 19 2 W08 Alt 3 TU1 43 Surface 2 19 2 W08-P No Action SH5 4 Passive 13 1570 46 W08-P Alt 1 TU1 22 Surface 2 19 2 W08-P Alt 3 TU1 22 Surface 2 19 2 W09 No Action 10 10 Surface 5 185 7 W09 Alt 1 TU1 10 Surface 2 19 2 W09 Alt 3 TU1 10 Surface 2 19 2 W10 No Action 10, TU5 2 Passive 7 418 7 W10 Alt 1 TU1 4 Surface 2 19 2 W10 Alt 3 TU1 4 Surface 2 19 2 W10-P No Action 10 2 Passive 5 190 7 W10-P Alt 1 TU1 4 Surface 2 19 2 W10-P Alt 3 TU1 4 Surface 2 19 2 W12 No Action TL8, TU1 10 Surface 3 69 4 W12 Alt 1 TU1 10 Surface 2 19 2 W12 Alt 3 TU1 10 Surface 2 19 2 W13 No Action SH2, TU5 10 Passive 7 418 7 W13 Alt 1 TU1, SH2 10 Surface 4 144 4
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Canopy Base Fireline Fuel Height Fire Flame Intensity Rate of Spread Unit Model (ft) Type Length (ft) (Btu/ft/sec) (chains/hour) W13 Alt 3 TU1, SH2 10 Surface 4 144 4 W13-P No Action 10 10 Surface 5 190 7 W13-P Alt 1 TU1 10 Surface 2 19 2 W13-P Alt 3 TU1 10 Surface 2 19 2 W16 No Action 8 47 Surface 1 6 1 W16 Alt 1 TU1 47 Surface 2 19 2 W16 Alt 3 TU1 47 Surface 2 19 2 W18 No Action TU3 5 Passive 7 403 22 W18 Alt 1 TU1 10 Surface 2 19 2 W18 Alt 3 TU1 29 Surface 2 19 2 W19-1 No Action 5, TU1 25 Surface 6 274 11 W19-1 Alt 1 TU1 25 Surface 2 19 2 W19-1 Alt 3 TU1 28 Surface 2 19 2 W19-2 No Action 5 3 Passive 6 265 19 W19-2 Alt 1 TU1, SH2 4 Surface 4 144 4 W19-2 Alt 3 TU1, SH2 26 Surface 4 144 4 W20-1 No Action 8 44 Surface 1 6 1 W20-1 Alt 1 TU1 58 Surface 2 19 2 W20-1 Alt 3 TU1 45 Surface 2 19 2 W20-2 No Action 8 44 Surface 1 6 2 W20-2 Alt 1 SH2 44 Surface 4 144 6 W20-2 Alt 3 SH2 44 Surface 4 144 6 W22 No Action 8, TU2 1 Passive 3 75 5 W22 Alt 1 TU1 31 Surface 2 19 2 W22 Alt 3 TU1 31 Surface 2 19 2 W23-1 No Action 10 14 Surface 5 185 7 W23-1 Alt 1 TU1, SH2 14 Surface 4 144 4 W23-1 Alt 3 TU1, SH2 31 Surface 4 144 4 W23-2 No Action 10 13 Surface 5 190 7 W23-2 Alt 1 SH2 13 Surface 4 144 6 W23-2 Alt 3 SH2 13 Surface 4 144 6 W24 No Action 8, TU5 26 Surface 7 418 5 W24 Alt 1 TU1, SH2 26 Surface 4 144 4 W24 Alt 3 TU1, SH2 26 Surface 4 144 4 W25-1 No Action 10, TU5 21 Surface 7 418 7 W25-1 Alt 1 TU1, SH2 41 Surface 4 144 4 W25-1 Alt 3 TU1, SH2 44 Surface 4 144 4 W25-2 No Action TU5 18 Surface 7 406 8 W25-2 Alt 1 TU1 41 Surface 2 19 2 W25-2 Alt 3 TU1 44 Surface 2 19 2 W25-3 No Action 10 3 Passive 5 185 7 W25-3 Alt 1 TU1, SH2 56 Surface 4 144 4 W25-3 Alt 3 TU1, SH2 29 Surface 4 144 4 W25-M No Action TU1 15 Surface 2 19 2 W25-M Alt 1 TU1 15 Surface 2 19 2 W25-M Alt 3 TU1 15 Surface 2 19 2 W34-P No Action SH5 4 Passive 13 1570 46 W34-P Alt 1 SH2 4 Surface 4 144 6
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W34-P Alt 3 SH2 4 Surface 4 144 6
The above table indicates what type of fire behavior could be expected if a fire were to occur within the different fuel types. Because of the variability in predicting fire behavior (fuels, weather, topography), a range could exist within the Twomile analysis area. Predicted fire behavior after all treatments are complete: flame lengths range from 1-4 feet with an average of 3 feet and fireline intensity ranges from 2 - 144 Btu/ft/sec with an average of 76 Btu/ft/sec. Predicted rate of spread by unit ranges from 1-6 chains per hour with an average of 3 chains per hour. The post treatment canopy base heights range from 4 - 65 feet with an average of 15 feet in Alternative 1 and 17 feet in Alternative 3. Different aspects, steeper slopes, fuel loading, and ladder fuels will all contribute to decreasing and/or increasing fire behavior. Two fuel models best represent the desired condition of the units by fuel type and predicted fire behavior with the assumption all proposed treatments are completed. They are listed below:
TL1 - timber litter fuel model with light to moderate fuel load of dead and woody material exist beneath a forest canopy. Very low rate of spread and very low flame length predicted. TU1 –timber understory fuel model with light fuel load of grass and/or shrub with litter from forest canopy. Low rate of spread and low flame length. SH2 – shrub fuel model with a moderate fuel load of woody shrubs and shrub litter about 1 foot in depth. Spread rate low; flame length low.
Indirect Effects Under Alternative 1 post-treatment fire behavior under 90th percentile weather conditions is predicted to be reduced to levels that either meet or move towards meeting the objectives stated in the purpose and need for the project. A decrease in surface, ladder and crown fuels would help facilitate the re- introduction of fire and may minimize fire behavior effects to resources. Thinning and biomass removal would reduce ladder fuels so that the potential for torching would be reduced. Units with the prescriptions of retaining 50 - 60% canopy cover and 50% biomass in clumpy arrangement have the potential to burn with patchy torching of individual trees or patches of trees, reflecting natural and desired conditions. Fireline production rate is predicted to double from 6 chains/hour pre-treatment to 7-40 chains/hour post-treatment on average.
A prescribed burn can reduce loads of fine fuels, duff, large woody fuels, rotten material, shrubs, and other live surface and ladder fuels, and hence change the potential spread rate and intensity of a future wildfire (Graham et al. 2004). The combination of thinning and prescribed fire is a particularly useful approach to fuel reduction because, while thinning can alter forest structure (density, canopy base height, canopy continuity, and canopy bulk density), prescribed fire can reduce surface fuel loads and increase canopy base height (Vaillant et al. 2009b). After thinning, biomass removal, and/or shredding and before prescribed burning and/or pile burning, the residual slash on the ground may temporarily increase the flame length and rate of spread in the unit; however, the fuel arrangement and canopy base height has been modified lessening the fire behavior. Behave Plus was used to predict the probability of mortality6; the program uses the mortality equations from First Order Fire Effects Model (FOFEM 4.0) (Reinhardt and others 1997). Probability of tree mortality (table 8) was modeled in the event of a wildland fire during 90th percentile weather conditions. The effects of a fire in relation to the fuel and stand conditions can determine the probability of mortality. Scorch height7 may be decreased.
6 The probability of mortality is the likelihood that a tree would be killed by a fire and is calculated based on scorch height, crown length, diameter, and species. 7 Scorch height is the vertical height from ground level to the highest point in the crown delineated by yellowing or browning needles (m or ft).
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Table 8: Alternative 1 - Probability of Mortality DBH (in) 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ Sugar Pine 6 5 3 0 0 0 0 0 0 0 0 Ponderosa Pine 8 6 5 1 1 0 0 0 0 0 0 White Fir 3 2 1 0 0 0 0 0 0 0 0 Incense Cedar 2 1 0 0 0 0 0 0 0 0 0 Black Oak 64 54 45 39 33 29 25 21 19 16 14
Fuel treatments would reduce potential fire severity and eventually allow fire to function as a natural process, helping to restore key ecosystem components and processes over time. In some cases, removal of trees from the canopy and understory could conceivably increase surface wind movement (Albini and Baughman 1979) and facilitate drying of live and dead fuel (Pollet and Omi 2002), although effective removal of ladder and surface fuel should mitigate these factors by reducing the fuel load and potential fire spread.
The proposed fuel breaks would provide for firefighter access and pre-existing control points for prescribed fire. Prescribed fire in spring or late fall when conditions are moist can reduce surface fuels in riparian corridors, maintain larger diameter logs, and reduce secondary fire effects.
Follow up herbicide treatment would occur 2‐5 years post‐shredding. Herbicide use would inhibit the regeneration of brush species along the fuelbreaks. Without the excessive regeneration of sprouting brush, these shredded areas would continue to serve as an effective fuel treatment in the long‐term. Shredded material would continue to decompose.
Cumulative Effects According to the Council on Environmental Quality (CEQ) NEPA regulations, ―cumulative impact‖ is the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non- Federal) or person undertakes such actions (40 CFR 1508.7). The actions listed and described were all derived by adding a one-mile buffer to the planning area boundary considering all projects for the next ten years. The rationale for the buffer is if a wildfire were to start in or near the planning area, connected treatments could affect fire behavior. STF and California Department of Forestry (CDF) databases were queried, including the Schedule of Proposed Actions (SOPA) to determine past, present and reasonably foreseeable future actions.
Alternative 1 would reduce fire hazard to the public and firefighters, and provide for increased protection of natural resources. As projects are completed, they create a mosaic of fuel treatments that could change fire behavior across the landscape. Treatment of surface fuels would result in efficient fireline construction rates and improve resistance to control, thereby reducing the negative effects of wildland fire. The proposed shredding reduces flame lengths; however, this treatment generates great quantities of heat, which can result in heavy crown scorch.
Given current accumulations of fuels in some stands, multiple prescribed fires—as the sole treatment or in combination with thinning—may initially be needed, followed by long-term maintenance burning or other fuel reduction treatments (for example, shredding, handcut, pile burning, etc.) to reduce fire severity. Fuelbreaks may also require long-term maintenance and repeated treatments.
Previous fuel treatments within the watershed on National Forest lands, state lands, and private property, in conjunction with this proposed action, and the anticipated future treatments would reduce fire behavior effects and increase fire management effectiveness and opportunities (figure 6). Thinning, prescribed fire, and maintenance burning planned into the future would reduce fuel loading and subsequent flame length and fire intensity, allowing handcrews an opportunity for suppression and minimize mortality to large fire resistant trees.
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Past Actions In order to understand the contribution of past actions to the cumulative effects of the proposed action and alternatives, this analysis relies on current environmental conditions as a proxy for the impacts of past actions. Since existing conditions and proposed treatments vary widely across these projects and even within individual units, it is difficult to summarize the fire effects. Treatments in the past have changed fire behavior on a unit-by-unit basis however were not SPLATS. Past actions are listed in three tables: Federal Land (Table 9), Private Land (Table 10), and Past Wildfires (Table 11). Existing conditions reflect the aggregate impact of all prior human actions and natural events that affected the environment and might contribute to cumulative effects through 2010.
Table 9: Past Actions - Federal Land (2000-2010) Project Treatment Acres* Camp 8 Thin/Biomass Removal 458 New Hunt Reforestation & Release Chemical area release 175 Ruby/Twin Rivers Pre-commercial Thin 14 Rust Resistant Sugar Pine Burn piles 19 South Dodge Burn piles 49 South Dodge Thin 360 Twin Thin Thin 1296 Twin Thin Burn piles 27 Wolfin, Camp 34, Niagara (site-prep) Shred 67 Wrights Creek Underburn 2,130 *Some acres may have received multiple treatments (e.g. pre-commercial thin & commercial thin); therefore, the same acres are listed under two different treatments
Table 10: Past Actions - Private Land (2000-2010) Landowner Timber Harvest Plan # Prescription* Acres** Private 87 CLCT 13 SASV 15 35 GSLN 146 SPI 67 ALPR 146 SLCN 110 Data obtained from CALFIRE website dated 12/28/2010-ftp://ftp.fire.ca.gov/forest/ *ALPR - Alternative Prescription, CLCT - Clearcut, SLCN - Selection, SASV – Sanitation Salvage, GSLN=Group Selection **Some acres may have received multiple treatments (e.g. ALPR & SLCN); therefore, the same acres are listed under two different treatments
Table 11: Past Wildfires (2000-2010) Fire Name Year Acres Camp 2000 41 Clavey 2008 11
Present Actions For the purposes of cumulative effects analysis, present actions are land disturbance actions with completed NEPA decisions that are not yet fully implemented on the ground. Table 12 lists the present Forest Service land actions. There are no present private land actions within analysis area.
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Table 12: Present Forest Service Land Actions Project Treatment Acres /Miles Phase II Thin, Biomass, Shred, Burn 2,099 Shred, Handcut, Pile, Burn 105 Shred, Burn 53
Handcut, Burn 86
Prescribed Fire 436
Twin Thin Prescribed Fire 1,296
Reasonably Foreseeable Future Actions For the purposes of cumulative effects analysis, reasonably foreseeable future actions are land disturbance projects with proposed actions published in the STF Schedule of Proposed Actions (SOPA) and without completed NEPA decisions. Table 13 lists the reasonably foreseeable future Forest Service land disturbance actions followed by a brief general descriptions of the project purpose types. There are no future private land actions within analysis area.
Twomile Ecological Restoration Projects B - F Due to nature, size, and proposed actions of Twomile Projects B – F it has been determined there are no significant consequences for fuels (purpose and need for each project on page 3 & 4). Detailed descriptions of each project can be found in the individual environmental analysis documents.
Table 13: Reasonably Foreseeable Future Actions
Project Purpose Decision Acres Hulls Habitat Meadow Improvement 2011 36 ac
Hulls Meadow: Encroaching conifers are proposed for removal from within the meadow within Hulls Meadow. This would be accomplished through biomass removal and hand cutting, piling and burning material on-site.
Alternative 2 No Action Direct Effects Alternative 2 (no action) is analogous to the existing condition, which is not consistent with the desired condition as identified in the Forest Plan. Without the fuels treatments, the fire behavior objectives would not be met and over time, the area would further depart from desired conditions. Canopy base heights would decrease. Existing surface fuel would remain at their current levels and increase with time as vegetation grows and dies.
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Indirect Effects Areas to facilitate safe and effective fire management activities and the ability to re-introduce fire into the ecosystem through wildfire and prescribed fire could be limited. The potential wildland fire spread and intensity could increase over time. Stands with dense stocking conditions could contribute to additional mortality (table 14), and add to the existing fuel loading. Resistance to control would remain the same and possibly decrease due to increased fuel loading and thickets of shade tolerant reproduction increasing in the understory, adding to the vertical fuel ladder. Fireline production rates would most likely decrease.
Table 14: No Action Alternative (Existing Conditions) – Probability of Mortality DBH (in) 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+
Sugar Pine 61 52 48 44 41 33 28 24 23 21 21
Ponderosa Pine 38 37 34 31 28 26 21 16 16 16 17
White Fir 48 43 35 29 26 22 20 20 20 20 20
Incense Cedar 51 44 42 40 38 31 27 26 26 26 26
Black Oak 86 82 74 65 60 55 51 49 47 45 43
Cumulative Effects Past, present, and reasonably foreseeable actions, as listed have contributed to the current existing condition and are used to depict the existing condition and the resultant fire behavior within the project area. Activities were analyzed within the project area and within a one-mile buffer to the project boundary for a ten-year period. Without the treatments, the level of protection for values at risk would diminish and areas for safe and effective deployment of suppression resources would be reduced. Direct attack of wildfire in most areas would not be feasible, increasing acres burned at a higher intensity and increasing fire suppression costs. Predicted flame lengths and rate of spread could potentially get worse. As brush and reproduction continue to encroach on the stand, the potential for crown fire initiation would increase. Without treatment, areas that could allow fire to function as a natural process would be limited. A continual decline in the process would persist and overall health and vigor of the stands would decline. Connectivity to other surface and ladder fuel treatments in the area would be lessened.
Alternative 3 Pre-commercial Thin Effects to fuel conditions are comparable to Alternative 1. In thinning units, select trees 12‖ dbh and less would be removed from the canopy to break the continuity and vertical arrangement of fuels to decrease the threat of crown fire activity within the treated area. Direct The activity generated slash from removal of the trees in combination with reducing surface fuels would produce effects similar to Alternative 1 in terms of reducing fireline intensities, flame lengths, and rates of spread. Indirect Prescribed fire and/or pile burning may scorch the lower limbs of residual trees and/or group torching may result where ladder fuels still exist. Mortality may also increase.
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While effects to fire behavior are expected to be similar to those described in Alternative 1, localized negative effects might occur in those areas proposed or treated that are clumpy and/or not as open. Areas left untreated could allow a fire to travel easily through the untreated areas. More surface activity fuels may be left, when compared to Alternative 1, due to operability of equipment. Cumulative Same as Alternative 1.
Air Quality The Forest-wide Standards and Guidelines for Air Quality require that burning shall be conducted to produce the lowest achievable smoke emissions. All prescribed burning would be done in accordance with Title 17, Smoke Management Guidelines for Agricultural and Prescribed Burning as required by the California Air Resource Board. Best Available Control Measures (BACMs) would be applied to ensure emissions reductions. Control measures include:
1. Attain lowest achievable emission rates by diluting or dispersing emissions. 2. Reduce the amount of pollutants per unit area treated. 3. Spread the concentration of smoke emissions over time. 4. Protect visibility in Federal Class I air sheds, Emigrant, and Carson-Iceberg Wilderness areas.
Smoke production is calculated using a series of multipliers (emission factors) applied to the amount of fuel consumed in each size class (Reinhardt and others 1997). For duff and large woody fuel, these multipliers vary with moisture content. The prescribed fire burn plan will include a smoke management plan that provides information on the estimated smoke emissions (particulate matter) projected for the prescribed burn and/or pile burn units. The Tuolumne County Air Pollution Control District approves the plan, regulates the permissive burn days, and prioritizes multiple prescribed burn projects in their air district to minimize the impacts of smoke. A wildfire following a prescribed burn or mechanical treatment would burn with less intensity and consume fewer fuels, resulting in fewer emissions. In addition, prescribed burns would be conducted during meteorological periods favorable to smoke dispersion. For more information, please visit Air Quality section located in Environmental Assessment.
Table 15: Comparison of Alternatives Alternative 1 Alternative 2 Alternative 3 Project Goals Proposed Action No Action Pre-Commercial Air Quality Approximately 3,592 tons of Hypothetical 1,857-acre Approximately 3,592 tons of PM10 Burn in accordance PM10 emissions are predicted wildfire would produce 145 emissions are predicted during with Title 17, Smoke during fire activities. A tons of emissions all at once, fire activities. A wildfire following Management Guideline wildfire following a prescribed which could affect air a prescribed burn or mechanical burn or mechanical treatment quality. treatment would burn with less would burn with less intensity intensity and consume fewer fuels, and consume fewer fuels, resulting in fewer emissions. resulting in fewer emissions. Smoke impact is reduced when Smoke impact is reduced when implemented over a 5-10 year implemented over a 5-10 year timeframe. timeframe.
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Fire and Fuels Treatment areas are Treatments would not occur Treatment areas are strategically Strategically place strategically placed to reduce and fuel conditions would placed to reduce severity of treatments across the severity of wildfires. Flame remain the same. Potential wildfires. Flame length: 1-4 ft, landscape to interrupt length: 1-4 ft, fireline intensity: for safe and effective fire fireline intensity: 2-144 Btu/ft/s, fire spread. Design 2-144 Btu/ft/s, rate of spread: management activities could rate of spread: 1-6 chains per treatments to facilitate 1-6 chains per hour. decrease. Flame length: hour. Resistance to control: direct safe and effective fire Resistance to control: direct 1-13 ft, fireline intensity: attack (persons with hand tools management activities. attack (persons with hand tools 6-1570 Btu/ft/s, rate of can generally attack fire at the can generally attack fire at the spread: 1-53 chains per head or flank). head or flank). hour. Resistance to control is limited to direct and indirect attack with mechanical equipment.
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References Agee, J.K. 1993. Fire ecology of Pacific Northwest Forests. Island Press, Wash. DC.
Albini, F. A. 1979. Spot fire distance from burning trees – a predictive model. GTR-INT-56. USDA Forest Service Intermountain Forest and Range Experiment Station. Ogden, UT.
Albini, F.; Baughman, R.G. 1979. Estimating windspeeds for predicting wildland fire behavior. GTR-INT-221. USDA Forest Service Intermountain Forest and Range Experiment Station. Ogden, UT. 92 pgs.
Anderson, Hal E. 1982. Aids to determining fuel models for estimating fire behavior. GTR-INT-122. Ogden, UT. Intermountain Forest Range Experimental Station, USDA Forest Service, 22p.
Blonski, Kenneth S, Schramel, John L. 1981. Photo series for quantifying natural forest residues: southern Cascades, northern Sierra Nevada. GTR-PSW-GTR-56. Berkeley, CA. Pacific Southwest Forest and Range Experiment Station, USDA Forest Service, 145 p.
Collins, B.M., M. Kelly, J.W. van Wagtendonk, and S.L. Stephens. 2007. Spatial patterns of large natural fires in Sierra Nevada wilderness areas. Landscape Ecology 22:545-557.
FBAT was developed for the National Interagency Fuels Technology Team (NIFTT) by Dale Hamilton (NIFTT member) of Systems for Environmental Management (SEM), Missoula, Montana.
Finney, M. A. 2006. An overview of FlamMap modeling capabilities. In: Andrews, P. L.; Butler, B. W., comps. Fuels Management—How to Measure Success: Conference Proceedings. 2006 March 28-30; Portland, OR. Proc. RMRS-P-41. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 809 p.
Fire Management Analysis (FMAPlus 3) user guide. http://www.fireps.com/fmanalyst3/
Graham, Russell T., McCaffrey, Sarah; Jain, Theresa B., 2004. Science basis for changing forest structure to modify wildfire behavior and severity. GTR-RMRS-GTR-120. Fort Collins, CO: USDA Forest Service Rocky Mountain Research Station. 43 pgs.
Maxwell, Wayne G.; Ward, Franklin R. 1980. Photo series for quantifying natural forest residues in common vegetation types of the Pacific Northwest. GTR-PNW-105. Portland, OR. http://www.fs.fed.us/pnw/publications/pnw_gtr105/
Mills, D.P. 2006. Wildland fire use success stories. Fire Management Today 66(4):16-19.
North, Malcolm; Stine, Peter; O'Hara, Kevin; Zielinski, William; Stephens, Scott 2009. An ecosystem management strategy for Sierran mixed-conifer forests. GTR-PSW-220. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 49 p.
Pollet, J.; Omi, P.N. 2002. Effects of thinning and prescribed burning on crown fire severity in ponderosa pine forests. International Journal of Wildland Fire. 11: 1-10.
Reinhardt, E.D., R.E. Keane, and J.K. Brown, 1997. First Order Fire Effects Model (FOFEM 4.0).
Scott, Joe H. and Burgan, Robert E. 2005. Standard Fire Behavior Fuel Models: A Comprehensive Set for Use with Rothermel’s Surface Fire Spread Model GTR-RMRS-153. USDA Forest Service Rocky Mountain Research Station. Fort Collins, Co. 80 pgs
USDA 2005. Stanislaus National Forest, Forest Plan Direction. Stanislaus National Forest, Sonora, CA.
Vaillant, N. M., J. Fites-Kaufman, A. L. Reiner, E. K. Noonan-Wright, and S. N. Dailey. 2009b. Effect of fuel treatments on fuels and potential fire behavior in California, USA, National Forests. Fire Ecology 5(2):14-29.
Van Wagner, C.E. 1977. Conditions for the start and spread of crown fire. Canadian Journal of Forestry. Res. 7, pgs.23-24.
Twomile Fire/Fuels Analysis Page 30
Twomile Ecological Restoration Project Fire & Fuels Appendix Anna Payne, Mi-Wok District Fuels Specialist February 2012
Fuels Inventory and Fuel Models Most of the units were covered during the common stand exam (CSE) and/or fuels inventory data collection. As units were added, changed, etc. fuels inventory data is not available. In those instances, FVS data was used to determine fuel loading, fuel model, canopy base height. During fuels inventory, one plot for every ten acres was analyzed. The fuel model selection guide located on pg 8 & 9 of the Standard Fire Behavior Fuel Models, GTR-RMRS-153 was used to aid in fuel model selection. The document contains two aids to fuel model selection: a fuel model selection guide and a set of crosswalks. Both the selection guide and crosswalks offer suggestions to consider, not conclusive results. The final fuel model must be made by the user based on experience with fire behavior in the fuelbed under consideration. The post fuel models were chosen by fuel type and the predicted fire behavior. Table 2 lists unit number, acres, fuel model, fuel loading by fuels class, canopy base height, and proposed prescription and treatment.
Conditions That Initiate Crown Fire* A fire moving through a stand of trees may move as a surface fire, an independent crown fire, or as a combination of intermediate types of fire (Van Wagner 1977). The initiation of crown fire behavior is a function of surface fireline intensity and of the forest canopy: its height above ground and moisture content (Van Wagner 1977). The critical surface fire intensity needed to initiate crown fire behavior can be calculated for a range of crown base heights and foliar moisture contents, and represents the minimum level of fireline intensity necessary to initiate crown fire (Table 1; Alexander 1988, Agee 1996). Fireline intensity or flame length below this critical level may result in fires that do not crown but may still be of stand replacement severity. For the limited range of crown base heights and foliar moistures shown in Table 1, the critical levels of flame length appear more sensitive to height to crown base than to foliar moisture (Alexander 1988).
Table 1: Flame Length Associated with Fireline Intensity
Flame lengths associated with critical levels of fireline intensity that are associated with initiating crown fire, using Byram's (1959) equation.
Foliar Moisture Height of Crown Base Content (%) in meters and feet
2 meters 6 meters 12 meters 20 meters 6 feet 20 feet 40 feet 66 feet m ft m ft m ft m ft 70 1.1 4 2.3 8 3.7 12 5.3 17 80 1.2 4 2.5 8 4.0 13 5.7 19 90 1.3 4 2.7 9 4.3 14 6.1 20 100 1.3 4 2.8 9 4.6 15 6.5 21 120 1.5 5 3.2 10 5.1 17 7.3 24
In order to avoid crown fire initiation, fireline intensity must be kept below the critical level. This can be accomplished by managing surface fuels such that fireline intensity is kept well below the critical level, or by raising crown base heights such that the critical fireline intensity is difficult to reach.
Twomile Fire/Fuels Appendix Page 1
In the field, the variability in fuels, topography and microclimate will result in varying levels of potential fireline intensity, critical fireline intensity, and therefore varying crown fire potential. Unit data with existing conditions, prescriptions, and treatments is listed in Table 2.
Table 2: Unit Data Unit Acres Fuel Canopy Fuels Fuels Fuels Fuel Prescription Treatment Model Base Class Class Class Loading Height 0"- 3"- 20.1" (t/a) (ft) 3" 20" + t/a t/a t/a Pine & Oak Thin/biomass/dozer D03 125 8, TU5 6 4 7 2 13 Restoration pile/burn D03-P 9 8, TU5 6 4 7 2 13 Fuels Reduction Handcut/pile/burn Fisher Emphasis – 10, Thin/biomass/dozer D04 51 6 4 9 5 18 Maintenance, TL7 pile/burn Openings Fisher Emphasis – Thin/biomass/dozer D05 4 8, TL7 6 4 9 5 18 Restoration, Openings pile/burn Fisher Emphasis – 10, Thin/biomass/dozer D06 79 10 5 8 7 20 Maintenance, TL7 pile/burn Openings Fisher Emphasis - Thin/biomass/dozer D07 18 8, TL7 7 4 9 8 21 Restoration, Openings pile/burn Fisher Emphasis - 10, Thin/biomass/dozer D08 69 17 6 13 4 23 Maintenance, SB2 pile/burn Openings Fisher Emphasis - D09 29 10 9 7 5 0 12 Maintenance, Prescribed burn Openings Top 1/3 slope, 10, Thin/biomass/shred/dozer D10 158 17 5 8 1 14 Openings, Shaded TU5 pile/burn fuelbreak 10, Fuels Reduction – D12 3 8 6 1 8 15 Biomass/pile/burn TL2 Threat Zone Fuels Reduction – 10, Threat Zone, Top 1/3 Thin/biomass/Shred/dozer D13 80 8 6 1 8 15 TL2 slope, Openings, pile/burn Shaded fuelbreak Fuels Reduction – D14 37 SH5 6 6 0 0 6 Shred/burn Threat Zone Fuels Reduction – D15 14 8, TL2 4 6 2 0 8 Prescribed burn Threat Zone Fuels Reduction – D16 4 8, SH5 7 6 0 0 6 Shred/burn Threat Zone Fuels Reduction – Threat Zone, Oak F11 240 8 6 2 1 0.1 3 Thin/biomass/shred/burn restoration, Pine density management F11-1 29 8, SH5 6 2 1 0.1 3 Fuels Reduction Shred/burn F11-2 8 8 6 2 1 0.1 3 Fuels Reduction Hand cut/pile/burn Oak restoration, Pine F13 22 8 20 3 1 4 Thin/biomass/shred/burn density management Oak restoration, Pine F14 126 8 20 7 5 12 Thin/biomass/shred/burn density management Oak restoration, Pine F16-1 44 8 1 3 6 9 Thin/biomass/burn density management F16-2 12 5 1 2 2 Fuels Reduction Biomass/Shred/Burn
10, L01 38 16 3 2 5 Fuels Reduction Shred/burn SH5
Twomile Fire/Fuels Appendix Page 2 Unit Acres Fuel Canopy Fuels Fuels Fuels Fuel Prescription Treatment Model Base Class Class Class Loading Height 0"- 3"- 20.1" (t/a) (ft) 3" 20" + t/a t/a t/a Fuels Reduction - L01-F 36 8, SH5 8 3 4 7 Shred/herbicide/burn Fuelbreak 10, Fuels Reduction - L02 7 6 6 6 Shred/burn SH5 Fuelbreak 10, Fuels Reduction - L02-F 84 13 4 9 13 Shred/herbicide/burn TU5 Fuelbreak L02-P 28 8, TU5 6 4 8 12 Fuels Reduction Shred/burn Fuels Reduction - L05-F 40 SH5 4 6 6 Shred/herbicide/burn Fuelbreak Top 1/3 slope, L06-1 21 8, SB2 7 4 1 20 25 Thin/biomass/burn Openings Pine & Oak L06-2 24 8, SB2 7 4 1 20 25 Thin/biomass/burn Restoration L08-1 18 8 20 5 5 Fuels Reduction Shred/burn L08-3 9 SH5 4 6 0 6 Fuels Reduction Shred/burn L08- Fuels Reduction - 11 8, SH5 18 6 6 Shred/herbicide/burn F1 Fuelbreak L08- 10, Fuels Reduction - 6 22 7 5 12 Shred/herbicide/burn F2 SH5 Fuelbreak Top 1/3 slope, L09 13 10 6 3 1 2 6 Thin/biomass/burn Openings Top 1/3 slope, L10-1 10 8, 5 14 3 1 4 Thin/biomass/shred/burn Openings Top 1/3 slope, L10-2 12 8, 5 14 3 1 4 Thin/biomass/shred/burn Openings Top 1/3 slope, Thin/biomass/shred/herbi L10-F 11 8, 5 14 3 1 4 Openings, Shaded cide/ fuelbreak burn TL4/ Top 1/3 slope, L11 9 20 6 7 13 Thin/biomass/shred/burn TU1 Openings L12 4 10 20 7 5 12 Fuels Reduction Shred/burn L12-F 8 10 2 7 5 12 Fuels Reduction Shred/burn Fisher – Restoration, Thin/biomass/shred/dozer L13 111 8, TL7 12 4 10 5 19 Openings, Shaded pile/burn fuelbreak Fisher – Restoration, 10, Thin/biomass/dozer L14 113 14 5 7 16 28 Openings up to 1.75 TU5 pile/burn acres 10, L15 65 11 6 9 4 19 Fuels Reduction Dozer pile/prescribe burn SB2 L16-F 11 10 4 7 5 12 Fuels Reduction Shred/burn 10, Pine & Oak Thin/biomass/dozer T01-1 108 10 6 10 5 21 TU5 Restoration pile/burn 10, Pine & Oak T01-2 12 10 6 10 5 21 Thin/biomass/shred/burn TU5 Restoration T01-3 6 10 5 1 2 3 Fuels Reduction Prescribed burn T01- 19 10 5 7 5 12 Fuels Reduction Hand cut/pile/burn F1 T03-3 33 10 3 7 5 12 Fuels Reduction Shred/burn Pine & Oak T03-F 8 10 3 4 10 0 14 Restoration, Shaded Thin/biomass/shred/burn fuelbreak Dozer pile/handcut/ T04 200 10, TU5 16 3 9 3 15 Fuels Reduction pile/burn Pine & Oak T06 83 10 20 4 11 2 17 Thin/biomass/burn Restoration
Twomile Fire/Fuels Appendix Page 3 Unit Acres Fuel Canopy Fuels Fuels Fuels Fuel Prescription Treatment Model Base Class Class Class Loading Height 0"- 3"- 20.1" (t/a) (ft) 3" 20" + t/a t/a t/a 10, Top 1/3, Shaded T07 151 11 4 6 4 14 Thin/biomass/shred/burn TL8 fuelbreak Dozer pile/handcut/ T09 349 9, SH2 17 4 4 Fuels Reduction pile/burn Fisher Emphasis - T11 41 8 17 4 8 6 18 Restoration (max dbh Thin/biomass/burn = 20") Fisher Emphasis - T12 36 10 4 5 13 1 19 Restoration (max dbh Thin/biomass/shred/burn = 20") Pine & Oak T13-1 58 TU5 11 5 5 1 11 Thin/biomass/burn Restoration Oak restoration, Pine T13-6 6 TL4 15 7 5 12 Thin/biomass/burn density management T13- 8 10 3 3 4 10 17 Fuels Reduction Handcut/burn P1 T13- 71 8, TU5 7 6 6 8 20 Fuels reduction Handcut/burn P2 10, Fisher Emphasis - T14 52 23 5 9 9 23 Thin/biomass/burn TL7 Maintenance 10, Top 1/3 slope, T14-1 120 14 4 8 6 18 Thin/biomass/shred/burn TL7 Openings 10, Top 1/3 slope, T14-2 65 8 4 6 6 16 Thin/biomass/shred/burn TU5 Openings 10, T15-P 34 18 6 8 2 16 Fuels Reduction Prescribed burn TL7 Pine & Oak Biomass/shred/dozer T19 112 8, TU5 12 5 5 21 31 Restoration pile/burn Fuels reduction - T21-1 76 10 7 5 11 2 18 Thin/biomass/shred/burn Defense Zone Fuels reduction - Thin/biomass/handcut/pile/ T21-2 6 10 7 5 11 2 18 Defense Zone burn Fuels reduction - T22 24 5 1 7 4 Shred/burn Defense Zone Fuels Reduction – 10, Threat Zone, Top 1/3 Thin/biomass/shred/dozer T25-1 132 9 4 3 10 17 SH5 slope, Shaded pile/burn fuelbreak Fisher Habitat Thin/biomass/shred/dozer T25-2 83 8, SH5 9 Maintenance, pile/burn Openings Fisher Emphasis T27 83 8, SH5 7 2 2 14 18 Thin/biomass/burn Maintenance Oak restoration, Pine T35 7 10 4 6 10 16 Thin/biomass/shred/burn density management 10, Oak restoration, Pine T36 166 18 3 2 3 8 Thin/biomass/shred/burn SH5 density management Oak restoration, Pine 10, T40 342 4 3 1 1 5 density management, Thin/biomass/shred/burn SH2 Shaded fuelbreak Oak restoration, Pine T43 21 TL7 20 5 15 20 Thin/biomass/burn density management Oak restoration, Pine T45 113 8, TL8 17 3 3 6 Thin/biomass/shred/burn density management Oak restoration, Pine T46 90 8, SH2 13 3 2 5 Thin/biomass/shred/burn density management
Twomile Fire/Fuels Appendix Page 4 Unit Acres Fuel Canopy Fuels Fuels Fuels Fuel Prescription Treatment Model Base Class Class Class Loading Height 0"- 3"- 20.1" (t/a) (ft) 3" 20" + t/a t/a t/a T47 85 5, SH5 2 2 2 Fuels reduction Shred/burn Oak restoration, Pine T48 60 8, SH2 13 2 1 2 5 Thin/biomass/shred/burn density management T49 6 SH5 20 6 6 Fuels Reduction Prescribed burn T53-P 330 8, TU5 16 5 8 3 16 Fuels Reduction Dozer pile/burn 10, TH01 32 13 2 1 3 Fuels Reduction Shred/burn SH5 Oak restoration, Pine TH02 155 8, SH5 13 2 2 2 6 density management, Thin/biomass/shred/burn Shaded fuelbreak 10, Top 1/3 slope, Shaded TH04 16 6 4 3 1 8 Thin/biomass/shred/burn TL8 fuelbreak TH06 10 SH5 4 6 6 Fuels Reduction Shred/burn TH07 16 SH3 4 7 4 Fuels Reduction Shred/burn Oak restoration, Pine TH08 188 SH5 10 3 2 5 density management, Thin/biomass/shred/burn Shaded fuelbreak TH09- 30 SH7 17 3 2 3 8 Top 1/3 slope Thin/biomass/burn 1 TH09- 7 10 22 6 6 Fuels Reduction Shred/burn 2 TH12 27 SH3 4 7 4 Fuels Reduction Shred/burn TH13 8 SH3 4 7 4 Fuels Reduction Shred/burn Oak restoration, Pine TH19 46 SH7 0 1 1 1 3 density management, Thin/biomass/shred/burn Shaded fuelbreak Top 1/3 slope, Shaded TH20 21 TL4 30 3 6 5 14 Thin/biomass/burn fuelbreak TH20- 53 8 45 5 1 6 Fuels reduction Hand cut/pile/burn F TH21- Top 1/3 slope, Shaded 25 TU5 19 2 2 4 Thin/biomass/shred/burn F fuelbreak TH23 35 SH5 10 3 3 1 7 Top 1/3 slope Thin/biomass/shred/burn Pine & Oak W01-1 25 8, TL7 33 1 23 4 28 Thin/biomass/shred/burn Restoration Pine & Oak W01-2 20 TL7 39 3 15 3 21 Thin/biomass/shred/burn Restoration Pine & Oak W02 195 8, TL5 22 2 5 7 14 Thin/handcut/pile/burn Restoration W05-1 26 8, TL8 25 3 3 4 10 Top 1/3 slope Thin/biomass/shred/burn 10, Pine & Oak W05-2 63 27 3 4 4 11 Thin/biomass/shred/burn TL8 Restoration W05- Meadow 7 GR3 30 1 1 2 Hand cut/pile/burn M Encroachment Top 1/3 slope, Shaded W07 336 10 23 4 9 7 20 Thin/biomass/shred/burn fuelbreak Top 1/3 slope - retain W08 103 10 6 5 10 5 20 55% CC, retain pine Thin/biomass/shred/burn bio W08-P 25 SH5 4 6 6 Fuels Reduction Shred/burn W09 31 10 10 4 10 7 21 Top 1/3 slope Thin/handcut/pile/burn 10, Top 1/3 slope, Shaded W10 255 2 4 10 5 19 Thin/biomass/shred/burn TU5 fuelbreak W10-P 7 10 2 7 5 12 Fuels Reduction Prescribed burn TL8, W12 88 10 6 6 Fuels Reduction Prescribed burn TU1
Twomile Fire/Fuels Appendix Page 5 Unit Acres Fuel Canopy Fuels Fuels Fuels Fuel Prescription Treatment Model Base Class Class Class Loading Height 0"- 3"- 20.1" (t/a) (ft) 3" 20" + t/a t/a t/a SH2, Pine & Oak W13 45 10 3 11 2 16 Thin/biomass/shred/burn TU5 Restoration W13-P 17 10 10 7 5 12 Fuels Reduction Hand cut/pile/burn Oak restoration, Pine W16 6 8 48 4 16 20 Thin/biomass/shred/burn density management W18 20 TU3 5 3 11 14 Top 1/3 slope Thin/biomass/shred/burn Top 1/3 slope, Shaded W19-1 138 5, TU1 25 3 2 3 8 Thin/biomass/shred/burn fuelbreak Oak restoration, Pine W19-2 17 5 3 4 10 1 15 Thin/biomass/shred/burn density management W20-1 34 8 44 4 15 19 Fuels Reduction Thin/biomass/shred/burn Oak restoration, Pine W20-2 23 8 44 7 5 12 Shred/burn density management Oak restoration, Pine W22 20 8, TU2 18 2 4 7 13 Thin/biomass/shred/burn density management Pine & Oak W23-1 40 10 14 2 3 4 9 Thin/biomass/shred/burn Restoration W23-2 21 10 13 7 5 12 Fuels Reduction Shred/burn Fisher Emphasis - W24 67 8, TU5 26 3 7 14 24 Thin/biomass/shred/burn restoration 10, Top 1/3 slope (max W25-1 84 21 4 7 9 20 Thin/biomass/shred/burn TU5 dbh 24') Top 1/3 slope, Shaded W25-2 201 TU5 18 4 6 6 16 Thin/biomass/shred/burn fuelbreak W25-3 42 10 3 4 8 1 13 Top 1/3 slope Thin/biomass/burn W25- Meadow 9 TU1 15 2 3 5 Hand cut/pile/burn M Encroachment W34-P 13 SH5 4 6 6 Fuels Reduction Shred/burn
Table 3: Methodology for Fire/Fuels Analysis Parameter Methodology Objective Flame Length (FL) Behave Plus <4 feet Fire Type (surface, passive, active) Behave Plus Surface Fireline Production Rate Fire Line Handbook >2 chains/hour Canopy Base Height (CBH) Plot data, CSE, FVS 20+ feet Mortality1 Behave Plus Less than 20% mortality in dominant and co-dominant trees
Behave Plus version 5.0.2 Behave Plus uses site specific input data to predict fire behavior for a point in time and space. Limitations of the Rothermel spread equation are well documented. Professional judgment based on experience and careful selection of inputs and interpretation of outputs can create accurate, repeatable, and consistent quantitative fire behavior predictions. Wind adjustment factor depends on sheltering of fuels from the wind. If fuels are not sheltered adjustment factor is a function of fuel bed depth. Wind Speed Adjustment Factor .3 - Partially Sheltered was used in Behave Plus. Partially Sheltered Fuel means fuel beneath patchy timber where it is not well sheltered; fuel beneath standing timber at midslope or higher on a mountain with wind blowing directly on the slope.
1 Probability of mortality is based on bark thickness and percent crown volume scorched, which are derived from scorch height, tree height, crown ratio, species, and tree diameter.
Twomile Fire/Fuels Appendix Page 6 Behave Plus – Mortality The probability of mortality is the likelihood that a tree will be killed by a fire. Probability of mortality is based on bark thickness and percent crown volume scorched, which are derived from scorch height, tree height, crown ratio, species, and tree diameter. The mortality calculations in FMA Crown Mass parallel the calculation methods in FOFEM (Reinhardt et al 1997). Probability can be interpreted as the probability of an individual tree dying or it can be multiplied by the number of trees on a site to estimate the number of trees that will die. The equations in the MORTALITY module in Behave Plus have been updated to match those of First Order Fire Effects Model (FOFEM 4.0), (Reinhardt, E.D., R.E. Keane, and J.K. Brown, 1997). Bark thickness is estimated from the tree species and diameter at breast height (DBH) from FOFEM. Fire mortality equations are from JFSP Report #05-2-1-105 Delayed Tree Mortality following Fire in Western Conifers (S. Hood, S. Smith, D. Cluck, E. Reinhardt, and K. Ryan, 2008). Mortality is listed by stand in table 4.
Table 4: Mortality Dodge 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 75 62 54 47 35 35 31 24 16 10 10 PP 42 42 34 28 19 11 10 8 6 6 6 WF 60 58 37 28 28 15 9 9 8 8 8 IC 66 59 50 48 48 45 35 20 20 20 20 BO 94 86 78 68 65 62 52 50 48 46 44 Fahey 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 3 2 1 1 0 0 0 0 0 0 0 PP 1 1 0 0 0 0 0 0 0 0 0 WF 2 1 1 0 0 0 0 0 0 0 0 IC 3 3 3 0 0 0 0 0 0 0 0 BO 59 52 45 40 34 30 26 22 20 17 15
Looney 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 49 42 37 37 29 12 7 7 7 7 7
PP 31 29 24 23 15 15 8 5 5 5 5
WF 26 13 8 6 6 6 6 6 6 6 6 IC 47 36 35 34 26 14 14 14 14 14 14 BO 73 69 65 61 54 51 43 41 39 37 35 Thompson 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 94 93 93 93 91 91 90 89 88 88 88 PP 74 74 73 72 72 71 71 70 70 70 70 WF 92 92 90 88 88 87 87 87 87 87 87 IC 88 88 88 88 87 86 85 85 85 85 85 BO 95 95 93 93 92 91 91 90 89 89 88 Twomile 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 62 52 48 45 42 34 31 28 28 26 26 PP 38 38 38 38 38 37 29 21 20 20 20 WF 49 45 37 31 29 26 25 25 25 25 25 IC 48 42 41 38 38 35 30 30 30 30 30 BO 91 89 77 62 57 51 49 47 45 44 42
Twomile Fire/Fuels Appendix Page 7 Wolfin 10" 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"+ SP 62 51 46 42 42 29 19 12 9 9 9 PP 36 36 30 23 18 13 8 5 5 5 5 WF 46 37 30 21 15 9 7 7 7 7 7 IC 53 42 39 38 33 16 15 15 15 15 15 BO 85 80 73 66 60 55 50 48 45 43 41
Principles of fire resistance are adapted from Agee 2002, Hessburg and Agee 2003 and displays principle, effect, advantage, and concerns to create a more fire resistant area (table 5).
Table 5: Principles of fire resistance Principle Effect Advantage Concerns Reduce surface Reduces potential Control easier; Surface disturbance less with fire fuels flame length less torching than other techniques Increase height to Requires longer Less torching Opens understory; may allow live crown flame length surface wind to increase Decrease crown Makes tree-to-tree Reduces crown Surface wind may increase and density crown less probable fire potential surface fuels may be drier Keep big trees of Less mortality for Generally restores Less economical; may keep trees at resistant species same intensity historic structure risk of insect attack
FLAMMAP FlamMap is widely used by the National Park Service (U.S. Department of the Interior), Forest Service (U.S. Department of Agriculture), and other federal and state land management agencies in support of fire management activities. FlamMap software creates raster maps of potential fire behavior characteristics (spread rate, flame length, crown fire activity, etc.) and environmental conditions (dead fuel moistures, mid-flame wind speeds, and solar irradiance) over the entire FARSITE landscape. These raster maps can be viewed in FlamMap or exported for use in a global information system, image, or word processor. FlamMap is not a replacement for FARSITE or a complete fire growth simulation model. There is no temporal component in FlamMap. It uses spatial information on topography and fuels to calculate fire behavior characteristics at one instant.
FlamMap uses the same spatial and tabular data as FARSITE: a Landscape (.LCP) File, Initial Fuel Moistures (.FMS) File, optional Custom Fuel Model (.FMD), optional Conversion (.CNV) File, optional Weather (.WTR) File, and optional Wind (.WND) File. • FlamMap incorporates the following fire behavior models: Rothermel’s 1972 surface fire model, Van Wagner’s 1977 crown fire initiation model, Rothermel’s 1991 crown fir spread model, and Nelson’s 2000 dead fuel moisture model.
FBAT FBAT outputs may suggest that a certain fire behavior characteristic is difficult to simulate on a given landscape even though that characteristic has frequently been observed during actual fire events, indicating problems with one or more of the fuel input layers. For example, the lack of simulated passive crown fire may indicate a problem with the fire behavior fuel model, canopy base height, and/or canopy cover layers. Fuel layers can then be refined or calibrated until the appropriate fire behavior is simulated by FBAT. California landscape 2010 was used and evaluated to simulate fire on the landscape.
Twomile Fire/Fuels Appendix Page 8 Crown fire modeling in FBAT utilized Scott and Reinhardt (2001) algorithm, which will increase the amount of active crown fire relative to passive crown fire. The landscape was evaluated and calibrated from site-specific data collected in the project area. They include:
Canopy base height (CBH) is a critical variable for determining the transition between surface fire and crown fire. The original landscape displayed 2 feet on average, average was 13 feet so CBH was multiplied by 3 if less than three feet to best represent the ocular measurement for pre- treatment fire behavior simulation. Post treatment units were increased to 20’ based on past treatment monitoring.
Canopy cover and effective mid-flame wind speed are inversely related. Thus, dense canopy cover will substantially decrease mid-flame wind speed, which subsequently reduces flame length, which in turn reduces the likelihood of transition from surface fire to crown fire. Canopy cover changed post treatment to a minimum of 60%.
Fuel models changed in post treatment FBAT run. The fuel models that represented a majority of the area simulating the treatments totally are TU5 to TU1 and TL8 to TL1.
Production Tables Sustained line production rates of 20-person crews for construction, burnout, and holding in chains/hour published in the Fireline Handbook, NWCG Handbook 3 (PMS 410-1), January 1998, page A-20.
Fuel Model 6, 10 8, 9 20-person Handcrew 6 ch/hr 7-40 ch/hr
Air Quality PM 10 EMISSION CALCULATION FOR BURNING OF MULTIPLE FUEL TYPES1,2 Section 80160 (b) of Subchapter 2 Smoke Management Guidelines for Agricultural and Prescribe Burning, Title 17, California Administrative Code states, “requires the submittal of smoke management plans for all burn projects greater than 10 acres in size or estimated to produce more than 1 ton of particulate matter”. To determine what the particulate matter (PM 10) amount is of your burn project please use the equation below and review the following examples.
Information needed for PM 10 Calculations: a. VT = Vegetation type b. ACRES VT = Estimated number of acres for VT c. FL est. = Estimated fuel loading in VT TONS per ACRE d. EV = PM10 emission/ton of fuel
Calculating PM10 Emissions from Prescribed Burning of multiple vegetation types: PM10 ton(s) emissions per VT = (number of acres VT) (FL tons per acre) (Emission Value (EV)) = ______ton(s)/VT PM10 ton(s) emissions per VT = (number of acres VT) (FL tons per acre) (Emission Value (EV)) = ______ton(s)/V Sum Total is the Estimated PM 10 for the project = _____ ton(s)/project
VEGETATION TYPE(S) ACRES (VT) x FL est. x EV* PM10 (ton(s) Basing Sage/Low Sage ( _____ ) x ( _____ ) x (0.010) = ______Ceanothus ( _____ ) x ( _____ ) x (0.010) = ______Chamise ( _____ ) x ( _____ ) x (0.009) = ______Giant Sequoia ( _____ ) x ( _____ ) x (0.007) = ______Grass/Forb ( _____ ) x ( _____ ) x (0.007) = ______Hackberry Oak ( _____ ) x ( _____ ) x (0.005) = ______Hardwood (Stocked) ( _____ ) x ( _____ ) x (0.003) = ______Hardwood (Non-stocked) ( _____ ) x ( _____ ) x (0.003) = ______Jeffrey Pine/Knobcone ( _____ ) x ( _____ ) x (0.007) = ______
Twomile Fire/Fuels Appendix Page 9 VEGETATION TYPE(S) ACRES (VT) x FL est. x EV* PM10 (ton(s) Live Oak (Canyon) ( _____ ) x ( _____ ) x (0.007) = ______Live Oak (Interior) ( _____ ) x ( _____ ) x (0.007) = ______Lodgepole Pine ( _____ ) x ( _____ ) x (0.007) = ______Manzanita (Productive Brush) ( _____ ) x ( _____ ) x (0.009) = ______Mixed Chaparral/Montane ( _____ ) x ( _____ ) x (0.008) = ______Mixed Conifer ( 7683 ) x ( 13) x (0.006) = 599 Oak (Black) ( _____ ) x ( _____ ) x (0.005) = ______Oak (Blue) ( _____ ) x ( _____ ) x (0.003) = ______Oak (White) ( _____ ) x ( _____ ) x (0.003) = ______Pinyon Pine ( _____ ) x ( _____ ) x (0.007) = ______Ponderosa Pine, Gray Pine ( _____ ) x ( _____ ) x (0.007) = ______Red Fir ( _____ ) x ( _____ ) x (0.007) = ______Wet Meadow ( _____ ) x ( _____ ) x (0.004) = ______Willow ( _____ ) x ( _____ ) x (0.007) = ______Sum Total of the Estimated PM10 for the project in tons/project = 599
* Percent combustion and PM10 emission factors for various fuel types derived from Table 8, Section 6, “Air Quality Conformity Handbook” from the USDA-Forest Service Air Resources / Fire Management Pacific Southwest Region dated November 1995. These are the vegetation’s estimated emissions values (EV) from the vegetation type as determined above to be used when the burn operator provides the vegetation’s fuel loading estimate per acre.
For additional information on emissions factors, see EPA document AP-42: “Compilation of Air Pollutant Emission Factors. Volume 1: Stationary Point and Area Sources,” Fifth Edition, AP-42, January 1995, U.S. EPA. Table 2.5-5.
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