Southern Sierra Nevada Wildfire Risk Assessment: Veg...

Southern Sierra Nevada Wildfire Risk Assessment:

Vegetation Condition Assessment Report

Prepared by: Don Helmbrecht

Wildland Fire Analyst, TEAMS Enterprise Unit

Prepared for: Phil Bowden, Regional Fuels Manager

USDA Forest Service, Pacific Southwest Region

May 18, 2015

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Southern Sierra Nevada Wildfire Risk Assessment: Vegetation Condition Assessment Report

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Contents Overview of the Vegetation Condition Assessment ........................................................................ 1

Purpose and background of the assessment ................................................................................ 1 Assessment area .......................................................................................................................... 2 Structure of report ....................................................................................................................... 2

Analysis Methods ............................................................................................................................ 2 Biophysical settings .................................................................................................................... 2 Natural range of variability and reference conditions ................................................................. 4 Current vegetation structure ........................................................................................................ 6 Landscape units ........................................................................................................................... 6 Vegetation departure metrics ...................................................................................................... 9

Analysis Results ............................................................................................................................ 11 Forested biophysical settings .................................................................................................... 11

California Montane Jeffrey Pine (-Ponderosa Pine) Woodland and Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland .................................................................. 11 Mediterranean California Red Fir Forest - Southern Sierra and Cascades variants .............. 14 Mediterranean California Mesic Mixed Conifer Forest and Woodland ................................ 16 Great Basin Pinyon-Juniper Woodland ................................................................................. 18 Central and Southern California Mixed Evergreen Woodland .............................................. 20 Mediterranean California Subalpine Woodland .................................................................... 23 California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna ....................... 24 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet ................................ 26 Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland ................................ 28

Shrubland biophysical settings .................................................................................................. 30 Inter-Mountain Basins Big Sagebrush Shrubland, Great Basin Xeric Mixed Sagebrush Shrubland, and Inter-Mountain Basins Montane Sagebrush Steppe ..................................... 30 Northern and Central California Dry-Mesic Chaparral ......................................................... 34

References ..................................................................................................................................... 37 Appendix A: Succession Class Mapping Rules ............................................................................ 39

Tables Table 1. LANDFIRE biophysical setting model groupings ............................................................ 3 Table 2. Succession class reference proportions for each biophysical setting ................................ 5 Table 3. Landscape level unit designations across the three forests (see also figure 4) .................. 7 Table 4. Landscape level for each biophysical setting .................................................................... 8 Table 5. Example of stratum vegetation departure calculations ...................................................... 9 Table 6. Vegetation condition results for the California Montane Jeffrey Pine (-Ponderosa Pine)

Woodland biophysical setting ............................................................................................... 12 Table 7. Vegetation condition results for the Mediterranean California Dry-Mesic Mixed Conifer

Forest and Woodland biophysical setting .............................................................................. 13 Table 8. Vegetation condition results for the Mediterranean California Red Fir Forest (Southern

Sierra variant) biophysical setting ......................................................................................... 15 Table 9. Vegetation condition results for the Mediterranean California Red Fir Forest (Cascades

variant) biophysical setting .................................................................................................... 16 Table 10. Vegetation condition results for the Mediterranean California Mesic Mixed Conifer

Forest and Woodland biophysical setting .............................................................................. 18 Table 11. Vegetation condition results for the Great Basin Pinyon-Juniper Woodland biophysical

setting .................................................................................................................................... 20

Table 12. Vegetation condition results for the Central and Southern California Mixed Evergreen Woodland biophysical setting ............................................................................................... 22

Table 13. Vegetation condition results for the Mediterranean California Subalpine Woodland biophysical setting ................................................................................................................. 24

Table 14. Vegetation condition results for the California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna biophysical setting .......................................................................... 26

Table 15. Vegetation condition results for the Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet biophysical setting ............................................................................... 28

Table 16. Vegetation condition results for the Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland biophysical setting .................................................................... 30

Table 17. Vegetation condition results for the Inter-Mountain Basins Big Sagebrush Shrubland biophysical setting ................................................................................................................. 32

Table 18. Vegetation condition results for the Great Basin Xeric Mixed Sagebrush Shrubland biophysical setting ................................................................................................................. 33

Table 19. Vegetation condition results for the Inter-Mountain Basins Montane Sagebrush Steppe biophysical setting ................................................................................................................. 34

Table 20. Vegetation condition results for the Northern and Central California Dry-Mesic Chaparral biophysical setting ................................................................................................ 36

Table 21. Tree, shrub, and herbaceous canopy cover classes used in LANDFIRE ...................... 39 Table 22. Tree, shrub, and herbaceous height classes used in LANDFIRE .................................. 39 Table 23. Final succession class (S-Class) mapping rules for each biophysical setting. Rules are

based on dominant lifeform and threshold existing vegetation cover (EVC) and existing vegetation height (EVH) values. Bold cells indicate an adjustment was made from the vegetation dynamics model threshold value. ......................................................................... 40

Figures

Figure 1. Southern Sierra Nevada Land and Resource Management Plan Environmental Impact Statement analysis area and National Forests .......................................................................... 1

Figure 2. Biophysical settings in the environmental impact statement analysis area ...................... 4 Figure 3. Succession classes in the environmental impact statement analysis area ........................ 6 Figure 4. Landscape units in the project extent. Biophysical settings are assigned to a landscape

unit for analysis based on historical disturbance regime characteristics and areal distribution (see also table 3). ..................................................................................................................... 8

Figure 5. Distribution of the California Montane Jeffrey Pine (-Ponderosa Pine) Woodland and Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland biophysical settings ................................................................................................................................... 11

Figure 6. Distribution of the Mediterranean California Red Fir Forest biophysical settings ........ 14 Figure 7. Distribution of the Mediterranean California Mesic Mixed Conifer Forest and

Woodland biophysical setting ............................................................................................... 17 Figure 8. Distribution of the Great Basin Pinyon-Juniper Woodland biophysical setting ............ 19 Figure 9. Distribution of the Central and Southern California Mixed Evergreen Woodland

biophysical setting ................................................................................................................. 21 Figure 10. Distribution of the Mediterranean California Subalpine Woodland biophysical setting

............................................................................................................................................... 23 Figure 11. Distribution of the California Lower Montane Blue Oak-Foothill Pine Woodland and

Savanna biophysical setting .................................................................................................. 25 Figure 12. Distribution of the Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland -

Wet biophysical setting ......................................................................................................... 27


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Figure 13. Distribution of the Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland biophysical setting ............................................................................................... 29

Figure 14. Distribution of the Inter-Mountain Basins Big Sagebrush Shrubland biophysical setting .................................................................................................................................... 31

Figure 15. Distribution of the Inter-Mountain Basins Montane Sagebrush Steppe biophysical setting .................................................................................................................................... 35


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Overview of the Vegetation Condition Assessment Purpose and background of the assessment This assessment was conducted to quantify vegetation departure from historical conditions—generally referred to as those prior to Euro-American settlement—for use in the Southern Sierra Nevada (SSN) Wildfire Risk Assessment (Scott et al. 2015) and Land and Resource Management Plan revision process. This regional-scale assessment provides information about the ecological integrity of terrestrial ecosystems across three National Forests—the Inyo, Sequoia, and Sierra—by comparing the current distribution of vegetation structure to the natural range of variability (NRV) in vegetation structure under historical conditions (Barrett et al. 2010). This assessment complements other plan revision work done in the region including the Sierra Nevada Bio-regional Assessment (USDA-FS 2015a) and the individual “early-adopter” forest-level assessments (USDA-FS 2015b, 2015c, 2015d).

We acknowledge that there are limitations to focusing on one ecosystem characteristic as a measure of the ecological integrity of terrestrial ecosystems and in using the natural range of variability of the historical period as the reference condition. Nevertheless, vegetation structure is a key characteristic to which other ecosystem characteristics respond (e.g., natural disturbance regimes, wildlife habitat and connectivity, plant and animal species diversity, and hydrologic regimes); and while the impacts of future stressors such as climate change and land use change are uncertain, ecosystem characteristics within the natural range of variability prior to Euro-American settlement are assumed to provide a benchmark of those which are resilient and adaptive (Landres et al. 1999; Keane et al. 2009).

Figure 1. Southern Sierra Nevada Land and Resource Management Plan Environmental Impact Statement analysis area and National Forests


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Assessment area The vegetation condition assessment uses the extent defined for the Southern Sierra Nevada Land and Resource Management Plan revision Environmental Impact Statement (figure 1). This extent (hereafter, EIS extent) encompasses the three National Forests being analyzed for plan revision and is based on the ‘South’ and ‘East South’ ecosubregions of the Sierra Nevada Bioregional Assessment (USDA-FS 2015a).

Structure of report This report opens with a description of the purpose and background of the assessment, assessment area, and structure of the report (this page). The report then describes the analysis methods used in conducting the assessment. Finally, the report summarizes the results by biophysical setting. The results section purposefully does not go into great detail in describing biophysical settings or associated disturbance regimes as this information can be found in the LANDFIRE (2007) vegetation dynamics model descriptions.

Analysis Methods This assessment was conducted using LANDFIRE data (Rollins 2009) and the vegetation departure methodology presented in the Interagency Fire Regime Condition Class (FRCC) Guidebook (Barrett et al. 2010). Information regarding the integration of these results with the Southern Sierra Nevada Wildfire Risk Assessment may be found in the report prepared by Scott et al. (2015).

Four primary inputs are required to assess vegetation departure using the fire regime condition class methodology:

1. Geospatial data representing biophysical settings.

2. Reference conditions for each biophysical setting.

3. Geospatially delineated landscape units for which to analyze and summarize the departure of individual biophysical settings.

4. Geospatial data of current vegetation structure.

Biophysical settings Biophysical settings represent potential vegetation that may have been present on the landscape prior to Euro-American settlement (Rollins 2009; Barrett et al. 2010). Biophysical setting map units are based on both the capability of the land and climate to support various vegetation types and the historical disturbance regime.

LANDFIRE geospatial biophysical setting data were provided by Phil Bowden, USDA Forest Service Pacific Southwest Regional Fuels Manager, at the EIS extent. Vegetation dynamics models describing the biophysical, vegetation, and disturbance characteristics of each biophysical setting map unit were acquired from the LANDFIRE website (www.landfire.gov).

A Web-based Meeting was held on September 4, 2013 to review the model descriptions for the biophysical settings located within the Southern Sierra Nevada project extent. Meeting participants included: Don Helmbrecht (TEAMS Fire Ecologist/meeting facilitator), Marc Meyer (Regional Ecologist), Jay Miller (Remote Sensing Specialist), Hugh Safford (Regional Ecologist), Joe Scott (Wildland Fire Analyst), and Neil Sugihara (Regional Fire Ecologist). Michele Slaton (GIS Specialist)

http://www.landfire.gov/


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and Heather Stone (Vegetation Management Specialist) provided review of the pinyon-juniper and sagebrush models post-meeting.

Table 1. LANDFIRE biophysical setting model groupings LANDFIRE Biophysical Setting Name LANDFIRE

Biophysical Setting Code

Presettlement Fire Regime1

LANDFIRE Model Used in

Vegetation Condition

Assessment

Inter-Mountain Basins Big Sagebrush Shrubland 10800 Big Sagebrush 610800 Inter-Mountain Basins Big Sagebrush Steppe 11250 Big Sagebrush 611260 Inter-Mountain Basins Montane Sagebrush Steppe 11260 Big Sagebrush 611260 Great Basin Xeric Mixed Sagebrush Shrubland 10790 Black and Low

Sagebrush 610790

California Mesic Chaparral 10970 Chaparral-Serotinous Conifers

611050

California Montane Woodland and Chaparral 10980 Chaparral-Serotinous Conifers

611050

Great Basin Semi-Desert Chaparral 11030 Chaparral-Serotinous Conifers

611050

Northern and Central California Dry-Mesic Chaparral 11050 Chaparral-Serotinous Conifers

611050

Sonora-Mojave Semi-Desert Chaparral 11080 Chaparral-Serotinous Conifers

611050

Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland

10270 Dry Mixed Conifer 610270

Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland 10580 Lodgepole Pine 610581 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet

10581 Lodgepole Pine 610581

Mediterranean California Mesic Mixed Conifer Forest and Woodland

10280 Moist Mixed Conifer 610280

California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna

11140 Oak Woodland 611140

Mediterranean California Mixed Oak Woodland3 10290 Mixed Evergreen 410140 Great Basin Pinyon-Juniper Woodland 10190 Pinyon-Juniper 610190 Mediterranean California Red Fir Forest - Cascades 10321 Red Fir 610321 Mediterranean California Red Fir Forest - Southern Sierra 10322 Red Fir 610322 Mediterranean California Subalpine Woodland 10330 Subalpine Forest 610330 Northern California Mesic Subalpine Woodland 10440 Subalpine Forest 610330 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Dry

10582 Lodgepole Pine 610330

Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland

10200 Subalpine Forest 610200

Rocky Mountain Subalpine-Montane Limber-Bristlecone Pine Woodland

10570 Subalpine Forest 610200

California Montane Jeffrey Pine(-Ponderosa Pine) Woodland 10310 Yellow Pine 610310 Mediterranean California Lower Montane Black Oak-Conifer Forest and Woodland

10300 Yellow Pine 610310

1 Van de Water and Safford (2011) presettlement fire regime vegetation types shown for reference. 3 Based on local knowledge and ancillary vegetation data, workshop participants felt that areas mapped as a Mediterranean California Mixed Oak Woodland biophysical setting were incorrectly classified and should be classified as Central and Southern California Mixed Evergreen Woodland (BpS model 410140).


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Models were reviewed for applicability to the scope and scale of the assessment. Participants chose to group certain models based on similarity of vegetation characteristics and fire regimes, primarily following the crosswalk between LANDFIRE biophysical setting and presettlement fire regime groups presented in Van de Water and Safford (2011). We reclassified the biophysical setting data to a total of fifteen biophysical setting models for use in the final assessment (table 1). The spatial distribution of biophysical settings is shown in figure 2.

Figure 2. Biophysical settings in the environmental impact statement analysis area

Natural range of variability and reference conditions LANDFIRE succession classes (S-Classes) represent vegetation development stages defined by species composition, vegetation structure, and stand age. The number and definition of S-Classes are unique to each biophysical setting and are described in the associated vegetation dynamics models. The standard “five-box,” or five-state, model uses the following classes:

• S-Class A: Early-development (i.e., post-replacement-severity disturbance)

• S-Class B: Mid-development, closed structure


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• S-Class C: Mid-development, open structure

• S-Class D: Late-development, open structure

• S-Class E: Late-development, closed structure

Uncharacteristic classes are also used to represent either native vegetation conditions that would be unlikely under the natural range of variability or situations where exotic species have partially or completely replaced the native species.

Table 2. Succession class reference proportions for each biophysical setting biophysical setting

Model Biophysical Setting Name Succession Class

A B C D E

410140 Central and Southern California Mixed Evergreen Woodland 10 45 45 N/A N/A

6101901 Great Basin Pinyon-Juniper Woodland 5 10 30 55 N/A

610200 Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland 20 20 60 N/A N/A

610270 Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland 20 10 25 40 5

610280 Mediterranean California Mesic Mixed Conifer Forest and Woodland 20 15 20 25 20

610310 California Montane Jeffrey Pine(-Ponderosa Pine) Woodland 15 5 30 45 5

610321 Mediterranean California Red Fir Forest - Cascades 20 20 15 25 20

610322 Mediterranean California Red Fir Forest - Southern Sierra 10 10 20 40 20

610330 Mediterranean California Subalpine Woodland 40 10 50 N/A N/A

610581 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet 5 25 5 5 60

610790 Great Basin Xeric Mixed Sagebrush Shrubland 15 60 15 10 N/A 610800 Inter-Mountain Basins Big Sagebrush Shrubland 15 50 25 5 5 611050 Northern and Central California Dry-Mesic Chaparral 10 90 N/A N/A N/A

611140 California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna 15 30 45 10 N/A

611260 Inter-Mountain Basins Montane Sagebrush Steppe 20 50 15 10 5 1 Reference proportions for BpS model 610190 were modified to match a locally adjusted model referenced in the Bodie Hills Conservation Action Plan (Provencher et al. 2009).

The LANDFIRE vegetation dynamics model descriptions also provide an estimate of the relative abundance of each S-Class (i.e., the proportion of the BpS occupied by the S-Class) to be expected under the natural disturbance regime (i.e., prior to Euro-American settlement). Relative abundance was estimated through state-and-transition modeling using the Vegetation Dynamics Development Tool (VDDT, ESSA Technologies Ltd. 2007). Each S-Class is equivalent to a vegetation state in the state-and-transition model and each state is assigned a number of years indicating how long it typically persists before succeeding to a new state. Probabilistic transitions between states are used to represent the effects of disturbances. The pre Euro-American settlement rates of succession and disturbance used in the model are based on scientific literature, currently available data, and the experience and judgement of the modelers (Rollins 2009). Each model was run for ten, 1,000-timestep simulations in vegetation dynamics development tool to determine the natural range of variability in the proportion of each S-Class. The


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mean relative abundance value for each S-Class within a biophysical setting was used as the reference condition for which to compare current conditions (table 2).

Current vegetation structure LANDFIRE maps the S-Class of individual biophysical settings based on expert-defined rules that identify applicable ranges of existing vegetation cover, existing vegetation height, lifeform, and to a lesser extent species composition, for each S-Class. Ideally, the S-Class mapping rules would be mutually exclusive and exhaustive, but this is not always the case. We reviewed the S-Class mapping rules of each vegetation dynamics model during the web-based meeting mentioned above to ensure the rules were mutually exclusive and exhaustive. The threshold values differentiating individual classes were also reviewed for local applicability. Adjustments to rules were based on input from meeting participants (Appendix A).

We remapped S-Class using updated geospatial data of existing vegetation cover, existing vegetation height, and disturbance type and severity (figure 3). These were LANDFIRE 2008 data (version 1.2.0) updated for disturbances through the year 2012, by Phil Bowden and his team.

Figure 3. Succession classes in the environmental impact statement analysis area

Landscape units The vegetation departure metrics of the Fire Regime Condition Class Guidebook methodology are scale-dependent, and it is therefore critically important to choose appropriately sized analysis units for


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summarizing results. The general rule-of-thumb is that units should be at an extent within which the full expression of succession classes would be expected to occur under the natural disturbance regime of the biophysical setting being analyzed (Barrett et al 2010).

Three levels of landscape units were derived to account for the various disturbance regimes of the biophysical settings being assessed (Table 3 and figure 4). The largest level is associated with the three national forests in the project area (Inyo, Sierra, and Sequoia). At the middle landscape unit level, the larger units are divided into two-to-three smaller nested units that are roughly associated with ranger districts. Landscape units at the smallest level divide the mid-level units into two-to-four smaller nested units. All landscape units were derived from hydrologic unit boundaries or major geographic or physical features (e.g., U.S. Route 395). Landscape units are named based on level and associated Forest, District, and geography.

Table 3. Landscape level unit designations across the three forests (see also figure 4) Level 3 Level 2 Level 1

Inyo Inyo:Mono-Mammoth Inyo:Mono-Mammoth:EA North Inyo:Mono-Mammoth:East Inyo:Mono-Mammoth:West Inyo:Mount Whitney Inyo:Mount Whitney:East Inyo:Mount Whitney:West Inyo:White Mountain Inyo:White Mountain:East Inyo:White Mountain:West

Sequoia Sequoia:Hume-Tule-Hot Springs Sequoia:Hume-Tule-Hot Springs:Hot Springs Sequoia:Hume-Tule-Hot Springs:Hume Lake East Sequoia:Hume-Tule-Hot Springs:Hume Lake West Sequoia:Hume-Tule-Hot Springs:Tule River Sequoia:Kern River Sequoia:Kern River:EA South Sequoia:Kern River:East Sequoia:Kern River:West

Sierra Sierra:Bass Lake Sierra:Bass Lake:East

Sierra:Bass Lake:West

Sierra:High Sierra Sierra:High Sierra:North

Sierra:High Sierra:South


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Figure 4. Landscape units in the project extent. Biophysical settings are assigned to a landscape unit for analysis based on historical disturbance regime characteristics and areal distribution (see also table 3).

Biophysical setting models were assigned to a landscape unit based on information from the LANDFIRE biophysical setting model descriptions (LANDFIRE 2007) and locally provided bioregional assessment documents (Meyer 2013a, Meyer 2013b, Safford 2013) about the historical size distribution of disturbances. Biophysical settings associated with disturbance regimes characterized by large disturbances were assessed using larger analysis units than those characterized by smaller disturbances. The acreage and areal distribution of the biophysical setting were also considered in assigning it to a landscape level. Table 4 shows the landscape level assigned to each biophysical setting.

Table 4. Landscape level for each biophysical setting Biophysical

Setting Model

Biophysical Setting Name Landscape Level

0410140 Central and Southern California Mixed Evergreen Woodland 1 0610200 Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland 1 0610330 Mediterranean California Subalpine Woodland 1 0610790 Great Basin Xeric Mixed Sagebrush Shrubland 1 0610800 Inter-Mountain Basins Big Sagebrush Shrubland 1 0611140 California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna 1 0610190 Great Basin Pinyon-Juniper Woodland 2


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Biophysical Setting Model

Biophysical Setting Name Landscape Level

0610270 Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland 2 0610280 Mediterranean California Mesic Mixed Conifer Forest and Woodland 2 0610310 California Montane Jeffrey Pine(-Ponderosa Pine) Woodland 2 0610321 Mediterranean California Red Fir Forest - Cascades 2 0610322 Mediterranean California Red Fir Forest - Southern Sierra 2 0610581 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet 2 0611260 Inter-Mountain Basins Montane Sagebrush Steppe 2 0611050 Northern and Central California Dry-Mesic Chaparral 3

Vegetation departure metrics We assessed vegetation departure following the Interagency Fire Regime Condition Class Guidebook methodology (Barrett et al. 2010), which compares the reference distribution of S-Classes (i.e., the proportion that each contributes to the whole expressed as a percent) to the current distribution of S-Classes for each combination of biophysical setting and landscape unit. We present two levels of vegetation departure metrics in this report: stratum, or biophysical setting, departure and S-Class departure.

Stratum vegetation departure is calculated by subtracting the sum of the “S-Class similarity” values (i.e., the lesser of the reference and current proportions) from 100 (table 5), for each combination of biophysical setting and landscape unit. The stratum vegetation departure is then classified into one of three vegetation condition class (VCC) categories as shown below. Stratum similarity is 59 percent, current departure is 41 percent, and vegetation condition class is 2.

• VCC1: low departure (less than or equal to 33 percent stratum vegetation departure)

• VCC2: moderate departure (greater than 33 percent and less than or equal to 66 percent stratum vegetation departure)

• VCC3: high departure (greater than 66 percent stratum vegetation departure)

Table 5. Example of stratum vegetation departure calculations Succession Class

(S-Class) Reference Proportion

(%) Current Proportion (%) S-Class Similarity

A-Early 15 3 3 B-Mid 40 25 25 C-Late 45 31 31

Uncharacteristic 0 41 0

S-Class departure is quantified as the percent difference of the current and reference proportions for individual S-Classes in each combination of biophysical setting and landscape unit.


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S-Class percent difference=CP-RP

max(RP,CP) *100

CP is the current proportion of the S-Class within the landscape unit and RP is the reference proportion. Positive values of this measure indicate that the current proportion of the S-Class exceeds the reference proportion; negative values indicate that the current is less than the reference proportion. For example, if the current proportion is twice the reference proportion, the S-Class percent difference is +50%; if the current proportion is half of the reference, then percent difference is -50%. S-Class percent difference is then classified into one of five relative amount categories:

• Trace: (< -66 percent difference)

• Under-represented: (≥ -66 percent difference and < 33 percent difference)

• Similar: (≥ -33 percent difference and ≥ 33 percent difference)

• Over-represented: (> 33 percent difference and ≤ 66 percent difference)

• Abundant: (> 66 percent difference)

These categories were further refined into deficit, similar, and surplus for use in the wildfire risk assessment (Scott et al. 2015).

We used the “2008” Interagency Fire Regime Condition Class Guidebook (Hann et al. 2004) breakpoints for classifying S-Class relative amount because it provides equal ranges of departure on both sides of the reference condition. The 2010 Guidebook changed the breakpoint value between similar and over-represented to 5 percent and the breakpoint value between over-represented and abundant to 80 percent, thus biasing the over-represented category. For example, with the 2010 breakpoints, a reference proportion of 10 percent and a current proportion of 11 percent, would be considered over-represented ((1/11) * 100 = 9.1 percent difference). A current proportion of 40 percent would also fall in the over-represented class ((30/40) * 100 = 75 percent difference), even though the first situation has 10 percent more acreage than the reference and the later has four times as much.


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Analysis Results Forested biophysical settings

California Montane Jeffrey Pine (-Ponderosa Pine) Woodland and Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland The California Montane Jeffrey Pine (-Ponderosa Pine) Woodland biophysical setting (yellow pine) is the most widely distributed and the largest biophysical setting mapped on National Forest System land within the EIS extent—290,000 acres on the Sequoia, 179,000 acres on the Sierra, and 175,000 acres on the Inyo (figure 5). Yellow pine forests were historically dominated by ponderosa pine (Pinus ponderosa) and/or Jeffery pine (Pinus jeffreyi) with a primarily open canopy structure due to a frequent, low-severity fire regime (LANDFIRE 2007). In the absence of fire, other conifer species become established and eventually co-dominate with yellow pine, making it difficult to discern from the mixed-conifer biophysical setting. Such is the case across much of the yellow pine biophysical setting distribution as a result of fire effective fire suppression. The yellow pine biophysical setting uses the standard five-state vegetation dynamics model.

Figure 5. Distribution of the California Montane Jeffrey Pine (-Ponderosa Pine) Woodland and Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland biophysical settings


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The Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland biophysical setting (dry-mesic mixed conifer) is mapped to 89,000 acres on the Sierra, and 63,000 acres on the Sequoia National Forests. This forest type is typically codominated by three or more conifer species including: ponderosa pine, sugar pine (Pinus lambertiana), white fir (Abies concolor), or incense cedar (Calocedrus decurrens). The dry-mesic mixed conifer biophysical setting also uses the standard five-state vegetation dynamics model.

Table 6. Vegetation condition results for the California Montane Jeffrey Pine (-Ponderosa Pine) Woodland biophysical setting

Landscape Unit

(National Forest System

acres)1

Succession Class2 A B C D E U

Reference Percent 15 5 30 45 5 0

Sequoia: Kern River (209,000)

Current % 30 18 38 5 8 0 % Difference 50 72 21 -88 39 0

Relative Amount

Over-represented Abundant Similar Trace Over-

represented NA

Vegetation Departure 40%, VCC2: Moderate Departure

Inyo:Mono-Mammoth (105,000)


Relative Amount Similar Abundant Over-

represented Trace Over-represented NA


Sierra:High Sierra

(103,000)

Current % 19 23 18 8 32 0 % Difference 22 78 -39 -83 84 0

Relative Amount Similar Abundant Under-

represented Trace Abundant NA


Sequoia: Hume-Tule-Hot

Springs (86,000)

Current % 15 26 17 9 32 1 % Difference -1 81 -42 -80 84 100


represented Trace Abundant Abundant


Sierra:Bass Lake

(76,000)



represented Trace Abundant Abundant


1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development closed, C: Mid-development open, D: Late-development open, E: Late-development closed, U: Uncharacteristic


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The yellow pine and dry-mesic mixed conifer biophysical settings are both assigned to fire regime group I (0 to 35 year frequency, surface severity) in the LANDFIRE vegetation dynamics models. We analyzed each biophysical setting at landscape unit level 2.

The yellow pine biophysical setting is moderately departed at the biophysical setting level in each of the five landscape units for which it summarized below (table 6). The Sequoia:Kern River landscape unit is the least departed at 40 percent departure and the Sierra:Bass Lake landscape unit is the most departed at 58 percent departure. At the S-Class level, a similar pattern is seen across each landscape unit. Mid- and late-development closed S-Classes (B and E) are in surplus, while only trace amounts of the late-development open S-Class (D) are present. The relative amount of the mid-development open (C) and early-development (A) S-Classes varies across landscape units.

The dry-mixed conifer biophysical setting is moderately departed at the biophysical setting level in each of the three landscape units for which it is summarized below (table 7). The Sierra:High Sierra landscape unit is the least departed at 51 percent departure and the Sierra:Bass Lake landscape unit is the most departed at 56 percent departure. At the S-Class level, each unit has a trace amount of the early-development S-Class (A) and an abundance of the late-development closed S-Class (E). The relative amount of the mid-development closed and open S-Classes (B and C) and the late-development open (D) S-Class varies across landscape units but in general there is relatively more area in closed than in open S-Classes within each unit.

Table 7. Vegetation condition results for the Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland biophysical setting

Landscape Unit

(Biophysical Setting acres)1



Sierra: Bass Lake (56,000)


Relative Amount Trace Similar Under-

represented Under-

represented Abundant NA



Springs (44,000)


Relative Amount Trace Over-

represented Similar Trace Abundant NA


Sierra: High Sierra

(33,000)



represented Under-

represented Under-





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Mediterranean California Red Fir Forest - Southern Sierra and Cascades variants The Mediterranean California Red Fir Forest biophysical settings (Southern Sierra and Cascades variants) are mapped at high elevations in the upper montane zone of the EIS extent, with the Southern Sierra variant residing above the Cascades variant in elevation (figure 6). Red fir (Abies magnifica) is the canopy dominant or co-dominant in both models but the Southern Sierra variant of the model includes a significant amount of western white pine (Pinus monticola) and generally lacks white fir, whereas the Cascades variant lacks western white pine and may include white fir (LANDFIRE 2007).

Both variants are mapped extensively to the Sierra National Forest (197,000 acres of the Southern Sierra variant and 115,000 acres of the Cascades variant). The Southern Sierra variant also comprises 82,000 acres of the Sequoia, and 76,000 acres of the Inyo National Forests.

Figure 6. Distribution of the Mediterranean California Red Fir Forest biophysical settings

The variants also differ by fire regime. The Southern Sierra variant is assigned to fire regime group III (35 to over 100 year frequency, mixed severity) in the LANDFIRE vegetation dynamics model as a result of discontinuous fuels due to natural breaks such as rock outcrops and wet meadows. The Cascades variant is assigned to fire regime group I (0 to 35 year frequency, surface severity) primarily due to more continuous fuels, however a considerable range of values has been reported in the literature for mixed- and surface-severity return intervals in this biophysical setting (LANDFIRE 2007). Both variants use the


15

standard five-state vegetation dynamics model. We analyzed each biophysical setting variant at landscape unit level 2.

The Southern Sierra variant is moderately departed at the biophysical setting level in each of the six landscape units for which it is summarized below (table 8). The Inyo:Mono-Mammoth landscape unit is the least departed at 34 percent departure and the Sequoia:Kern River landscape unit is the most departed at 40 percent departure. At the S-Class level, many S-Classes are within plus or minus 33 percent of the reference proportion, and with the exception of the late-development open S-Class (D) all are within plus or minus 66 percent of the reference proportion. The late-development open S-Class shows the most departure with only trace amounts in five of the six landscape units.

Table 8. Vegetation condition results for the Mediterranean California Red Fir Forest (Southern Sierra variant) biophysical setting

Landscape Unit




Sierra: High Sierra

(157,000)


Relative Amount Similar Similar Similar Trace Over-

represented NA



Springs (47,000)

Current % 13 8 13 12 53 0 % Difference 25 -20 -34 -69 62 0

Relative Amount Similar Similar Under-

represented Trace Over-represented NA

VCC 37%, VCC2: Moderate Departure

Sierra: Bass Lake (42,000)


Relative Amount

Over-represented Similar Similar Trace Over-

represented NA


Inyo:Mount Whitney (39,000)


Relative Amount

Over-represented

Over-represented Similar Trace Similar NA



Current % 26 10 28 6 31 0 % Difference 61 -5 28 -86 36 0

Relative Amount

Over-represented Similar Similar Trace Over-

represented NA


Sequoia: Kern River (33,000)


Relative Amount

Over-represented

Under-represented

Under-represented

Under-represented

Over-represented NA

VCC 40%, VCC2: Moderate Departure 1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development closed, C: Mid-development open, D: Late-development open, E: Late-development closed, U: Uncharacteristic


16

The Cascades variant shows low departure at the biophysical setting level in both of the landscape units for which it is summarized below (table 9). The Sierra: High Sierra landscape unit is 19 percent departed and the Sierra:Bass Lake landscape unit is 20 percent departed. At the S-Class level, the early- and mid-development S-Classes are in deficit and the late-development S-Classes are in surplus. All S-Classes are within plus or minus 66 percent of the reference proportion with the exception of the mid-development closed S-Class (B), which basically absent from the landscape units.

Table 9. Vegetation condition results for the Mediterranean California Red Fir Forest (Cascades variant) biophysical setting


Mediterranean California Mesic Mixed Conifer Forest and Woodland The Mediterranean California Mesic Mixed Conifer Forest and Woodland biophysical setting (mesic mixed conifer) is mapped extensively on the west slope of the Sierras (figure 7), comprising 149,000 acres of the Sequoia and 144,000 acres of the Sierra National Forests. This forest type is typically co-dominated by three or more conifer species including: white fir, ponderosa pine, sugar pine, or incense cedar (LANDFIRE 2007). The mesic mixed conifer biophysical setting is typically found on cooler aspects and at higher elevations than the dry-mesic mixed conifer biophysical setting.

The mesic mixed conifer biophysical setting is assigned to fire regime group I (0 to 35 year frequency, surface severity) in the LANDFIRE vegetation dynamics model but also includes a relatively frequent mixed-severity mean fire return interval of 45 years. The biophysical setting uses the standard five-state vegetation dynamics model. We analyzed this biophysical setting at landscape unit level 2.

Landscape Unit




Sierra: High Sierra

Current % 11 0 11 48 30 0 % Difference -44 -98 -30 47 34 0

Relative Amount

Under-represented Trace Similar Over-

represented Over-

represented NA

Vegetation Departure 19%, VCC1: Low Departure

Sierra: Bass Lake

Current % 13 1 9 47 31 0 % Difference -37 -97 -43 47 36 0

Relative Amount

Under-represented Trace Under-

represented Over-

represented Over-

represented NA

VCC 20%, VCC1: Low Departure


17

Figure 7. Distribution of the Mediterranean California Mesic Mixed Conifer Forest and Woodland biophysical setting

At the S-Class level, the early- and mid-development S-Classes (A, B, and C) are in deficit and the late-development closed S-Class (E) is in surplus for each landscape unit. The late-development open S-Class (D) is similar to the reference proportion in the Sequoia:Hume-Tule-Hot Springs and Sierra:High Sierra landscape units and under-represented in the Sierra:Bass Lake landscape unit.

The mesic mixed conifer biophysical setting shows low departure at the biophysical setting level in the Sequoia:Hume-Tule-Hot Springs (30 percent) and Sierra:High Sierra (28 percent) landscape units and moderate departure (47 percent) in the Sierra:Bass lake landscape unit (table 10).


18

Table 10. Vegetation condition results for the Mediterranean California Mesic Mixed Conifer Forest and Woodland biophysical setting

Landscape Unit





Springs (117,000)

Current % 7 9 10 24 50 0 % Difference -67 -38 -49 -4 60 0

Relative Amount Trace Under-

represented Under-

represented Similar Over-represented NA


Sierra:Bass Lake

(82,000)


Relative Amount

Under-represented Trace Trace Under-



Sierra:High Sierra

(65,000)


Relative Amount

Under-represented

Under-represented

Under-represented Similar Over-

represented NA



Great Basin Pinyon-Juniper Woodland The Great Basin Pinyon-Juniper Woodland biophysical setting (pinyon-juniper) is mapped extensively on the Inyo National Forest (figure 8), comprising 229,000 acres. This forest type can be dominated by a mix of pinyon pine (Pinus monophylla) and juniper (Juniperus osteosperma), or nearly pure stands of either species (LANDFIRE 2007). Common associates include mountain mahogany (Cercocarpus ledifolius) and sagebrush (Artemisia sp.).

There is much uncertainty in regards to the historical fire regime of this biophysical setting due to a lack of quantitative data (LANDFIRE 2007). The current fire regime is influenced by climate change and the presence of invasive plant species, particularly cheatgrass (Bromus tectorum) and red brome (Bromus rubens), which increase fire frequency. These issues make it challenging to apply natural range of variability concepts to this biophysical setting.

We used the four-state vegetation dynamics model and reference proportions from the Bodie Hills Conservation Action Plan (Provencher et al. 2009) to analyze this biophysical setting. S-Class A represents early-development; S-Class B represents shrub dominated, mid-development; S-Class C represents tree dominated mid-development; and S-Class D represents late-development.


19

Figure 8. Distribution of the Great Basin Pinyon-Juniper Woodland biophysical setting

The pinyon-juniper biophysical setting is assigned to fire regime group III (35-100+ year frequency, mixed severity) in the LANDFIRE vegetation dynamics model. We analyzed this biophysical setting at landscape unit level 2.

The pinyon-juniper biophysical setting is moderately departed at the biophysical setting level in each of the three landscape units for which it is summarized below (table 10). The Inyo:Mono-Mammoth landscape unit is the least departed at 38 percent departure and the Inyo:White Mountain landscape unit is the most departed at 53 percent departure. At the S-Class level, the Inyo:White Mountain and Inyo:Mono-Mammoth landscape units follow the same pattern of departure. They are both over-represented by the tree dominated, mid-development S-Class (C) and in deficit of the early-development (A), shrub dominated, mid-development (B), and late-development (E) S-Classes. The Inyo:Mount Whitney landscape unit is also deficit in the early- and late-development S-Classes but has a similar proportion of the shrub and tree dominated S-Classes (B and C) to the reference condition.


20

Table 11. Vegetation condition results for the Great Basin Pinyon-Juniper Woodland biophysical setting

1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development (shrub dominated), C: Mid-development (tree dominated), D: Late-development, U: Uncharacteristic

Central and Southern California Mixed Evergreen Woodland The Central and Southern California Mixed Evergreen Woodland biophysical setting (mixed evergreen) is mapped along an elevation gradient of the lower montane zone (figure 9), comprising 130,000 acres of the Sequoia National Forest and 101,000 acres of the Sierra National Forest. This forest type is dominated by canyon live oak (Quercus chrysolepis) and black oak (Quercus velutina) with scattered conifers (LANDFIRE 2007; USDA-FS 2015c, 2015d) and typically forms an ecotone between the foothill oak and pine woodland and mixed conifer vegetation types.

Landscape Unit



Reference Percent 5 10 30 55 NA 0

Inyo:White Mountain (147,000)

Current % 0 0 75 17 NA 8 % Difference -96 -100 60 -69 NA 100

Relative Amount Trace Trace Over-

represented Trace NA Abundant




Relative Amount Trace Similar Similar Trace NA Abundant



Current % 0 0 60 32 NA 8 % Difference -98 -100 50 -42 NA -100


represented Under-

represented NA Abundant



21

Figure 9. Distribution of the Central and Southern California Mixed Evergreen Woodland biophysical setting

Fire is the most common disturbance agent of this biophysical setting and it is assigned to fire regime group I (0 to 35 year frequency, surface severity) in the LANDFIRE vegetation dynamics model. This biophysical setting uses a three-state model. S-Class A represents early-development, S-Class B represents mid-development, and S-Class C represents late-development. The canopy structure is typically closed across all classes. We analyzed this biophysical setting at landscape unit level 1.

The mixed evergreen biophysical setting is moderately departed at the biophysical setting level in each of the primary landscape units for which it is summarized below (table 12). At the S-Class level there is a strong deficit in the early- and late-development S-Classes with greater than 80 percent of the acres falling in the mid-development class.


22

Table 12. Vegetation condition results for the Central and Southern California Mixed Evergreen Woodland biophysical setting

Landscape Unit (Biophysical Setting

acres)1


Reference Percent 10 45 45 NA NA

Sierra:High Sierra:South (39,000)

Current % 2 93 5 NA NA 1 % Difference -81 52 -90 NA NA 100


represented Trace NA NA Abundant


Sequoia:Kern River:West (35,000)


Relative Amount

Under-represented

Over-represented Trace NA NA Abundant


Sierra:Bass Lake:West (34,000)


Relative Amount

Under-represented

Over-represented Trace NA NA Abundant


Sequoia:Hume-Tule-Hot Springs:Hot Springs

(29,000)





Sierra:Bass Lake:East (26,000)





Sequoia:Hume-Tule-Hot Springs:Tule River

(25,000)





1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development C: Late-development, U: Uncharacteristic


23

Mediterranean California Subalpine Woodland The Mediterranean California Subalpine Woodland biophysical setting (subalpine woodland) is mapped at high elevations of the Sierra Nevada range across the EIS extent (figure 10). The biophysical setting contributes to 137,000 acres of the Inyo National Forest and 74,000 acres of the Sierra National Forest. This forest type is dominated by whitebark pine (Pinus albicaulis), mountain hemlock (Tsuga mertensiana), and red fir (LANDFIRE 2007).

Lightning ignitions are frequent in subalpine woodland forests but fires remain small due to discontinuous fuel, rocky soil, and typical ridgetop location of the biophysical setting (LANDFIRE 2007). The biophysical setting is assigned to fire regime group V (200 years and over frequency, replacement severity) in the vegetation dynamics model but we analyzed it at landscape unit level 1 due to the small patch size nature of the fire regime. This biophysical setting uses a three-state vegetation dynamics model. S-Class A represents early-development, S-Class B represents a late-development, closed krumholtz structure; and S-Class C represents late-development, open non-krumholtz structure.

The subalpine woodland biophysical setting shows low departure across each of the primary landscape units in which it is mapped (table 13).

Figure 10. Distribution of the Mediterranean California Subalpine Woodland biophysical setting

At the S-Class level, the proportion of the early- and late-development S-Classes (A and C) are similar to the reference proportion. The krumholtz S-Class (B) is not mapped within the biophysical setting.


24

Table 13. Vegetation condition results for the Mediterranean California Subalpine Woodland biophysical setting

Landscape Unit (Biophysical setTing

acres)1


Reference Percent 40 10 50 NA NA 0

Inyo:Mount Whitney:West (54,000)

Current % 30 0 66 NA NA 4 % Difference -25 -100 24 NA NA 100

Relative Amount Similar Trace Similar NA NA Abundant


Sierra:High Sierra:North (54,000)

Current % 40 0 59 NA NA 1 % Difference 1 -100 15 NA NA 100



Inyo:White Mountain:West (39,000)




Inyo:Mono-Mammoth:West (37,000)




Sierra:High Sierra:South (23,000)




1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Late-development closed (krumholtz), C: Late-development open (non-krumholtz), U: Uncharacteristic

California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna The California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna biophysical setting (blue oak-foothill pine) is the largest biophysical setting mapped within the EIS extent, primarily along the western border, but comprises a relatively small amount of National Forest land: 100,000 acres on the Sierra, 73,000 acres on the Sequoia, and only 1,000 acres on the Inyo (figure 11).

The blue oak-foothill pine biophysical setting is characterized by open stands of blue oak (Quercus douglasii) and foothill, or grey, pine (Pinus sabiniana). Widespread alteration though land use change,


25

invasive species establishment, and fire suppression have occurred in this forest type and the understory is now typically dominated by non-native grasses and forbs (LANDFIRE 2007; USDA-FS 2015c, 2015d).

The blue oak-foothill pine biophysical setting uses a four-state vegetation dynamics model (LANDFIRE 2007). S-Class A represents early-development, S-Class B represents mid-development open, S-Class C represents late-development open, and S-Class D represents late-development closed. The biophysical setting is assigned to fire regime group I (0 to 35 year frequency, surface severity). We analyzed this model at landscape unit level 1.

Figure 11. Distribution of the California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna biophysical setting

The blue oak-foothill pine biophysical setting is moderately departed at the biophysical setting level in the Sequoia:Kern River:West (36 percent) and Sierra:Bass Lake:East landscape units (41 percent) but shows low departure (26 percent) in the Sierra:High Sierra:South (table 14). At the S-Class level, the relative amount varies between landscape units. Fourteen to 35 percent of the biophysical setting in each landscape unit is mapped as uncharacteristic as a result of non-native annual grassland dominance.


26

Table 14. Vegetation condition results for the California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna biophysical setting

Landscape Unit (biophysical

setting acres)1



Sierra:High Sierra:South

(59,000)

Current % 23 4 47 12 NA 14 % Difference 36 -86 4 15 NA 100

Relative Amount

Over-represented Trace Similar Similar NA Abundant


Sequoia:Kern River:West

(35,000)

Current % 16 18 30 1 NA 35 % Difference 3 -39 -34 -86 NA 100

Relative Amount Similar Under-

represented Under-

represented Trace NA Abundant


Sierra:Bass Lake:East (33,000)


Relative Amount Trace Trace Similar Under-



1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development open, C: Late-development open, D: Late-development closed, U: Uncharacteristic

Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet The Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland (wet variant) biophysical setting (cool/wet lodgepole pine) is mapped to a relatively small portion of Forest Service land in the EIS extent: 46,000 acres on the Sierra and 41,000 acres on the Inyo (figure 12).

The cool/wet lodgepole pine biophysical setting is characterized by non-contiguous stands of generally moderate to dense lodgepole pine. Other conifers may be present but are not codominant (LANDFIRE 2007).


27

Figure 12. Distribution of the Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet biophysical setting

The cool/wet lodgepole pine biophysical setting uses the standard five-state vegetation dynamics model. Limited information is available about the disturbance regime of Sierra lodgepole (LANDFIRE 2007). The biophysical setting is assigned to fire regime group III (35 to 100 plus year frequency, mixed severity). We analyzed the biophysical setting at the landscape unit 2 level.

The cool/wet lodgepole pine biophysical setting is highly departed at the biophysical setting level in each of the three primary landscape units summarize below (table 15). At the S-Class level, less than 10 percent of the acreage in each landscape unit is in the late-development closed S-Class (E), whereas the reference condition is 60 percent.


28

Table 15. Vegetation condition results for the Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet biophysical setting

Landscape Unit

(biophysical setting acres)1



Sierra:High Sierra

(42,000)

Current % 16 0 0 81 3 0 % Difference 68 -100 -100 94 -95 0

Relative Amount Abundant Trace Trace Abundant Trace NA

Vegetation Departure 87%, VCC3: High Departure


Current % 31 0 5 57 6 0 % Difference 84 -100 4 91 -90 100

Relative Amount Abundant Trace Similar Abundant Trace Abundant



Current % 21 0 7 70 3 0 % Difference 76 -100 25 93 -95 100

Relative Amount Abundant Trace Similar Abundant Trace Abundant



Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland The Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland biophysical setting (limber-bristlecone) is mapped to a relatively small portion (36,000 acres) of the Inyo National Forest (figure 13). Great Basin bristlecone pine (Pinus longaeva), limber pine (pinus flexilis), and whitebark pine may exist individually or as mixed stands in this BpS (LANDFIRE 2007).

Sparse fuels typically limit fire size and severity in the limber-bristlecone biophysical setting. The biophysical setting uses a three-state vegetation dynamics model. S-Class A repents early-development, S-Class B represents mid-development, and S-Class C represents late-development. Canopy structure is typically open.


29

Figure 13. Distribution of the Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland biophysical setting

The limber-bristlecone biophysical setting is assigned to fire regime group III (35 to 100 plus year frequency, mixed severity) in the LANDFIRE vegetation dynamics model, however we analyzed the biophysical setting at the landscape unit 1 level due to its characteristic small fire patch size and its distribution on the Inyo.

The limber-bristlecone biophysical setting shows low departure across the two landscape units for which it was summarized below (table 16). The Inyo:White Mountain:East landscape unit is16 percent departed at the biophysical setting level and the Inyo:White Mountain:West landscape unit is 32 percent departed. At the S-Class level, both landscape units are over-represented by the early-development S-Class (A) and have a similar proportion of the mid-development S-Class (B) to the reference. The Inyo:White Mountain:East landscape unit has 27 percent less acres of vegetation in the late-development S-Class (C) and the Inyo:White Mountain:West landscape unit has 54 percent less.


30

Table 16. Vegetation condition results for the Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland biophysical setting


setting acres)1


Reference Percent 20 20 60 NA NA 0

Inyo:White Mountain:East

(24,000)

Current % 30 24 44 NA NA 2 % Difference 34 16 -27 NA NA 100

Relative Amount

Over-represented Similar Similar NA NA Abundant


Inyo:White Mountain:West

(7,000)

Current % 45 22 28 NA NA 5 % Difference 56 10 -54 NA NA 100

Relative Amount

Over-represented Similar Under-

represented NA NA Abundant


1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development, C: Late-development, U: Uncharacteristic

Shrubland biophysical settings

Inter-Mountain Basins Big Sagebrush Shrubland, Great Basin Xeric Mixed Sagebrush Shrubland, and Inter-Mountain Basins Montane Sagebrush Steppe Three sagebrush BpSs are intermixed in the EIS extent primarily on the northern portion of the Inyo National Forest (figure 14).

• Inter-Mountain Basins Big Sagebrush Shrubland,

• Great Basin Xeric Mixed Sagebrush Shrubland, and

• Inter-Mountain Basins Montane Sagebrush Steppe.

Although analyzed independently, the structure definitions and reference proportions for these biophysical settings are similar in their vegetation dynamics models (Appendix A).


31

Figure 14. Distribution of the Inter-Mountain Basins Big Sagebrush Shrubland biophysical setting

Both Inter-mountain Basin types are dominated by big sagebrush (Artemisia tridentata) and are assigned to fire regime group IV (35 to 100 plus year frequency, replacement severity). The Great Basin Xeric type is dominated by black sagebrush (Artemisia nova) and low sagebrush (Artemisia arbuscula) and is assigned to fire regime group III (35 to 100 plus year frequency, mixed severity) (LANDFIRE 2007).

The Inter-mountain Basin types use a five-state vegetation dynamics model and the Great Basin Xeric type uses a four-state model. Each of the models follow a similar pattern, where S-Class A represents an herbaceous dominated early- development state, S-Class B represents a shrub dominated mid-development open state, S-Class C represents either a mid- or late-development shrub state, and S-Classes D and E represent transition to tree dominance. We analyzed the Inter-Mountain Basins Big Sagebrush Shrubland and Great Basin Xeric Mixed Sagebrush Shrubland biophysical settings at the landscape unit 1 level and the Inter-Mountain Basins Montane Sagebrush Steppe at the landscape unit 2 level.

The Inter-Mountain Basins Big Sagebrush Shrubland is moderately departed at the biophysical setting level across all landscape units with the exception of the Inyon:Mount Whitney:West unit (table 17). At the S-Class level, the early-development S-Class (A) is in deficit and there exists a surplus of the uncharacteristic S-Class due to denser canopy cover than under the reference condition. There is significant variability across landscape units in the mid- and late-development S-Classes.


32

Table 17. Vegetation condition results for the Inter-Mountain Basins Big Sagebrush Shrubland biophysical setting

1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development open, C: Mid-development closed, D: Late-development open (tree dominated), E: Late-development closed (tree dominated), U: Uncharacteristic


setting acres)1




(65,000)

Current % 0 1 51 5 11 33 % Difference -100 -99 51 -2 54 100


represented Similar Over-represented Abundant


Inyo:Mono-Mammoth:West

(42,000)



represented Under-

represented Similar Abundant


Inyo:Mono-Mammoth:East

(35,000)

Current % 0 0 49 7 15 29 % Difference -100 -100 49 29 67 100


represented Similar Abundant Abundant


Inyo:Mount Whitney:East

(34,000)

Current % 0 1 46 7 7 40 % Difference -100 -99 45 25 26 100


represented Similar Similar Abundant



(27,000)





Sequoia:Kern River:East (27,000)

Current % 7 48 3 0 1 41 % Difference -57 -4 -86 -100 -84 100

Relative Amount

Under-represented Similar Trace Trace Trace Abundant


Inyo:Mount Whitney:West

(21,000)

Current % 2 65 15 0 0 19 % Difference -89 23 -42 -98 -96 100

Relative Amount Trace Similar Under-

represented Trace Trace Abundant



33

The Great Basin Xeric Mixed Sagebrush Shrubland biophysical setting is highly departed at the biophysical setting level across all landscape units (table 18). At the S-Class level, there are only trace amounts of the early- and mid-development S-Classes (A and B) across landscape units and greater than 50 percent of each unit is mapped as uncharacteristic. As with the Inter-Mountain Basins Big Sagebrush Shrubland biophysical setting the uncharacteristic assignment is due to denser canopy cover than is specified in the reference condition.

Table 18. Vegetation condition results for the Great Basin Xeric Mixed Sagebrush Shrubland biophysical setting


setting acres)1




(65,000)

Current % 0 1 18 18 NA 63 % Difference -100 -99 17 45 NA 100

Relative Amount Trace Trace Similar Over-




(59,000)

Current % 0 1 22 18 NA 59 % Difference -98 -99 32 43 NA 100

Relative Amount Trace Trace Similar Over-



Inyo:Mount Whitney:East

(30,000)



represented Similar NA Abundant


Inyo:Mono-Mammoth:West

(25,000)

Current % 0 0 9 16 NA 75 % Difference -100 -100 -43 37 NA 100

Relative Amount Trace Trace Under-

represented Over-



Inyo:Mono-Mammoth:East

(20,000)

Current % 0 0 7 37 NA 56 % Difference -100 -100 -52 73 NA 100

Relative Amount Trace Trace Under-

represented Abundant NA Abundant


1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development open, C: Late-development open, D: Late-development closed (tree dominated), U: Uncharacteristic

The Inter-Mountain Basins Montane Sagebrush Steppe biophysical setting is moderately departed at the biophysical setting level in three of the four landscape units for which it is summarized (table 19). The


34

Inyo:White Mountain landscape unit is highly departed at 73 percent. At the S-Class level, the early-development S-Class (A) is in deficit and there exists a surplus of the uncharacteristic S-Class due to denser canopy cover than under the reference condition. There is significant variability across landscape units in the mid- and late-development S-Classes.

Table 19. Vegetation condition results for the Inter-Mountain Basins Montane Sagebrush Steppe biophysical setting

Landscape Unit




Inyo:White Mountain (86,000)



represented Under-

represented Abundant Abundant





represented Under-

represented Abundant Abundant




Relative Amount

Under-represented Trace Over-



Sequoia:Kern River

(16,000)

Current % 25 13 38 0 4 19 % Difference 21 -73 61 -97 -26 100

Relative Amount Similar Trace Over-

represented Trace Similar Abundant


1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Mid-development open, C: Late-development closed, D: Late-development open (tree dominated), E: Late-development closed (tree dominated), U: Uncharacteristic

Northern and Central California Dry-Mesic Chaparral The Northern and Central California Dry-Mesic Chaparral biophysical setting (chaparral) is mapped primarily to the western edge of the EIS extent (figure 15), comprising 116,000 acres of the Sequoia National Forest and 47,000 acres of the Sierra National Forest.

Chamise (Adenostoma fasciculatum) and various ceanothus, and manzanita (Arctostaphylos) species comprise this vegetation type. Chaparral burns in high-intensity, replacement-severity fires and fire is generally needed to regenerate vegetation (LANDFIRE 2007).


35

This biophysical setting uses a two-state vegetation dynamics model where S-Class A represents the early-development post-replacement state and S-Class B represents the late-development state. The chaparral biophysical setting is assigned to fire regime group IV (35 to 100 plus year frequency, replacement severity). We assessed this biophysical setting at the landscape unit 3 level, which is the broadest landscape level—generally depicting National Forests.

Figure 15. Distribution of the Inter-Mountain Basins Montane Sagebrush Steppe biophysical setting

The chaparral biophysical setting is moderately departed at the biophysical setting level in both the Sequoia (44 percent departure) and Sierra (57 percent departure) landscape units (table 19). At the S-Class level, the late-development S-Class (B) is under-represented in both landscape units. The early- development S-Class (A) is at a similar proportion to the reference condition in the Sequoia unit and under-represented in the Sierra unit. Both units also have a significant amount of the uncharacteristic S-Class mapped primarily due to the presence of introduced annual grasses.


36

Table 20. Vegetation condition results for the Northern and Central California Dry-Mesic Chaparral biophysical setting

Landscape Unit



Reference Percent 10 90 NA NA NA 0

Sequoia (117,000)

Current % 15 46 NA NA NA 39 % Difference 32 -49 NA NA NA 100

Relative Amount Similar Under-

represented NA NA NA Abundant


Sierra (46,000)

Current % 5 38 NA NA NA 57 % Difference -54 -58 100 NA NA 100

Relative Amount

Under-represented

Under-represented NA NA NA Abundant


1 Acres of the biophysical setting, within the landscape unit, on Forest Service land. Values are rounded to the nearest thousand. 2 A: Early-development, B: Late-development, U: Uncharacteristic


37

References Barrett, S.; Havlina, D.; Jones, J.; Hann, W.; Frame, C.; Hamilton, D.; Schon, K.; Demeo, T.; Hutter, L.;

and Menakis, J. 2010. Interagency Fire Regime Condition Class Guidebook. Version 3.0 [Homepage of the Interagency Fire Regime Condition Class website, USDA Forest Service, US Department of the Interior, and The Nature Conservancy]. [Online], Available: www.frcc.gov [November 2013].

ESSA Technologies Ltd. 2007. Vegetation Dynamics Development Tool User Guide, Version 6.0. Prepared by ESSA Technologies Ltd., Vancouver, BC. 196 pp.

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Appendix A: Succession Class Mapping Rules The following rules (table 21 through table 23) reflect adjustments recommended by Don Helmbrecht (TEAMS Wildland Fire Analyst/meeting facilitator), Marc Meyer (Regional Ecologist), Jay Miller (Remote Sensing Specialist), Hugh Safford (Regional Ecologist), Joe Scott (Wildland Fire Analyst), Neil Sugihara (Regional Fire Ecologist), Michele Slaton (GIS Specialist), and Heather Stone (Vegetation Management Specialist) during the biophysical setting model review process.

Table 21. Tree, shrub, and herbaceous canopy cover classes used in LANDFIRE Value Tree Canopy Cover Value Shrub Canopy Cover Value Herbaceous Canopy Cover 101 Tree Cover >= 10 and < 20% 111 Shrub Cover >= 10 and < 20% 121 Herbaceous Cover >= 10 and < 20% 102 Tree Cover >= 20 and < 30% 112 Shrub Cover >= 20 and < 30% 122 Herbaceous Cover >= 20 and < 30% 103 Tree Cover >= 30 and < 40% 113 Shrub Cover >= 30 and < 40% 123 Herbaceous Cover >= 30 and < 40% 104 Tree Cover >= 40 and < 50% 114 Shrub Cover >= 40 and < 50% 124 Herbaceous Cover >= 40 and < 50% 105 Tree Cover >= 50 and < 60% 115 Shrub Cover >= 50 and < 60% 125 Herbaceous Cover >= 50 and < 60% 106 Tree Cover >= 60 and < 70% 116 Shrub Cover >= 60 and < 70% 126 Herbaceous Cover >= 60 and < 70% 107 Tree Cover >= 70 and < 80% 117 Shrub Cover >= 70 and < 80% 127 Herbaceous Cover >= 70 and < 80% 108 Tree Cover >= 80 and < 90% 118 Shrub Cover >= 80 and < 90% 128 Herbaceous Cover >= 80 and < 90% 109 Tree Cover >= 90 and <= 100% 119 Shrub Cover >= 90 and <= 100% 129 Herbaceous Cover >= 90 and <= 100%

Table 22. Tree, shrub, and herbaceous height classes used in LANDFIRE Value Herbaceous Height Value Shrub Height Value Forest Height

101 Herbaceous Height 0 to 0.5 meters 104 Shrub Height 0 to 0.5 meters 108 Forest Height 0 to 5 meters

102 Herbaceous Height 0.5 to 1.0 meters 105 Shrub Height 0.5 to 1.0 meter 109 Forest Height 5 to 10 meters

103 Herbaceous Height > 1.0 meter 106 Shrub Height 1.0 to 3.0 meters 110 Forest Height 10 to 25 meters

107 Shrub Height > 3.0 meters 111 Forest Height 25 to 50 meters

112 Forest Height > 50 meters

Resource Name

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Table 23. Final succession class (S-Class) mapping rules for each biophysical setting. Rules are based on dominant lifeform and threshold existing vegetation cover (EVC) and existing vegetation height (EVH) values. Bold cells indicate an adjustment was made from the vegetation dynamics model threshold value.


Biophysical Setting Name S-Class Lifeform EVC Min

EVC Max

EVH Min

EVH Max

410140 Central and Southern California Mixed Evergreen Woodland A Herb/Shrub Any Any Any Any

A Tree Any Any 108 108

B Tree Any Any 109 110

C Tree Any Any 111 112

610190 Great Basin Pinyon-Juniper Woodland A Herb 121 121 Any Any

B Shrub 111 111 Any Any

C Tree 101 102 Any Any

D Tree 103 104 Any Any

610200 Inter-Mountain Basins Subalpine Limber-Bristlecone Pine Woodland A Herb/Shrub Any Any Any Any


B Tree 101 104 109 109

C Tree 101 104 110 110

610270 Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland A Herb/Shrub Any Any Any Any


B Tree 105 109 110 110

C Tree 101 104 110 110

D Tree 101 104 111 112

E Tree 105 109 111 112

610280 Mediterranean California Mesic Mixed Conifer Forest and Woodland A Herb/Shrub Any Any Any Any


B Tree 105 109 110 110

C Tree 101 104 110 110

D Tree 101 104 111 112

E Tree 105 109 111 112


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EVC Max

EVH Min

EVH Max

610310 California Montane Jeffrey Pine(-Ponderosa Pine) Woodland A Herb/Shrub Any Any Any Any


B Tree 104 109 110 110

C Tree 101 103 110 110

D Tree 101 103 111 111

E Tree 104 109 111 111

610321 Mediterranean California Red Fir Forest - Cascades A Herb/Shrub Any Any Any Any


B Tree 105 109 110 110

C Tree 101 104 110 110

D Tree 101 104 111 112

E Tree 105 109 111 112

610322 Mediterranean California Red Fir Forest - Southern Sierra A Herb/Shrub Any Any Any Any


B Tree 104 107 110 110

C Tree 101 103 110 110

D Tree 101 103 111 111

E Tree 104 108 111 111

610330 Mediterranean California Subalpine Woodland A Herb/Shrub Any Any Any Any

B Tree 105 109 108 108

C Tree 101 104 108 112

610581 Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland - Wet A Herb/Shrub Any Any Any Any


B Tree 105 109 109 109

C Tree 101 104 109 109

D Tree 101 104 110 112

E Tree 105 109 110 112

Resource Name

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EVC Max

EVH Min

EVH Max

610790 Great Basin Xeric Mixed Sagebrush Shrubland A Herb 121 121 Any Any


C Shrub 112 112 Any Any


610800 Inter-Mountain Basins Big Sagebrush Shrubland A Herb 121 123 Any Any




E Tree 102 105 Any Any

611050 Northern and Central California Dry-Mesic Chaparral A Herb Any Any Any Any

A Shrub 111 113 Any Any


611140 California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna A Herb/Shrub Any Any Any Any


B Tree Any Any 109 109

C Tree 101 104 110 112

D Tree 105 106 110 112

611260 Inter-Mountain Basins Montane Sagebrush Steppe A Herb 121 127 Any Any




E Tree 102 107 Any Any

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