National Park Service

U.S. Department of the Interior

Natural Resource Stewardship and Science

Lassen Volcanic National Park

Natural Resource Condition Assessment

Natural Resource Report NPS/NRSS/WRD/NRR—20132/725
ON THE COVER

Lassen Volcanic National Park

Photo courtesy of Cheryl Bartlett 
Lassen Volcanic National Park

Natural Resource Condition Assessment

Natural Resource Report NPS/NRSS/WRD/NRR—20132/725

Paul R. Adamus

Water Resources Science Program

Oregon State University

Corvallis, Oregon

and

Adamus Resource Assessment, Inc.

Corvallis, Oregon

Dennis C. Odion, Gregory V. Jones, Lorin C. Groshong, Ryan Reid

Department of Environmental Studies

Southern Oregon University

Ashland, Oregon

This report was prepared under Task Agreement J8W07100032 (Cooperative Agreement

H8W07060001) between the National Park Service and Southern Oregon University.

November 2013

U.S. Department of the Interior

National Park Service

Natural Resource Stewardship and Science 

Fort Collins, Colorado
ii

The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, 

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screen readers, please email irma@nps.gov. 

Please cite this publication as:

Adamus, P. R., D. C. Odion, G. V. Jones, L. C. Groshong, and R. Reid. 2013. Lassen Volcanic 

National Park Natural Resource Condition Assessment. Natural Resource Report 

NPS/NRSS/WRD/NRR—20132/725. National Park Service, Fort Collins, Colorado.

NPS 111/122753, November 2013
iii

Contents

Page

Figures........................................................................................................................................... vii

Tables............................................................................................................................................. ix

Appendices..................................................................................................................................... xi

Executive Summary..................................................................................................................... xiii

Acknowledgments......................................................................................................................... xv

Prologue ........................................................................................................................................ xv

1.0 NRCA Background................................................................................................................... 1

2.0 Introduction and Resource Setting............................................................................................ 5

3.0 Study Scoping, Design, and Implementation............................................................................ 9

3.1 Project Responsibilities ..................................................................................................... 9

3.2 Framework and Information Gathering............................................................................. 9

4.0 Natural Resource Conditions and Trends............................................................................... 13

4.1 Changes in Precipitation, Snowpack, and Water Availability......................................... 13

4.1.1 Background.............................................................................................................. 13

4.1.2 Regional Context ..................................................................................................... 14

4.1.3.1 Historical Climate Change.................................................................................... 15

4.1.3.2 Future Climate Change ......................................................................................... 16

4.1.4 Indicators and Criteria to Evaluate Condition and Trends....................................... 16

4.1.4.1 Maximum Annual Depth and Volume of Snowpack by Location ....................... 17

4.1.4.2 Timing and Rate of Spring Snow Melt and Discharge in Springs and Streams... 18

4.1.4.3 Perennial Stream Extent, Seasonal Flow Volume, Wetted Width........................ 20

4.1.4.4 Number, Area, and Distribution Pattern of Wetlands, Ponds, and Lakes............. 23

4.2 Changes in Surface Waters and Their Resources............................................................ 24

4.2.1 Background.............................................................................................................. 24

4.2.2 Regional Context ..................................................................................................... 24

4.2.3 Issues Description .................................................................................................... 25
iv

4.2.3.1 Impacts from Climate Change .............................................................................. 25

4.2.3.2 Impacts from Air Pollution: Deposition of Atmospheric Nitrogen and Sulfur .... 25

4.2.3.3 Impacts from Air Pollution: Deposition of Other Contaminants.......................... 25

4.2.3.4 Aquatic Impacts of Fires, Fire Control Activities, and Vegetation Change ......... 26

4.2.3.5 Visitor-associated Water Contamination .............................................................. 26

4.2.3.6 Impacts from Ecologically Harmful Aquatic Plants and Animals........................ 26

4.2.3.7 Natural Sources..................................................................................................... 26

4.2.4 Indicators, Criteria, Condition, and Trends ............................................................. 27

4.2.4.1 Water Quality Threshold Exceedances................................................................. 27

4.2.4.2 Diversity of Native Aquatic Species and Habitats................................................ 29

4.2.4.3 Water Bodies with Ecologically Harmful Species................................................ 32

4.3 Changes in Terrestrial Vegetation ................................................................................... 34

4.3.1 Background.............................................................................................................. 34

4.3.2 Regional Context ..................................................................................................... 36

4.3.3 Issues Description .................................................................................................... 37

4.3.3.1 Fire Regimes, Fire Suppression, and Fuels Management..................................... 37

4.3.3.2 Climate Change and Fire ...................................................................................... 38

4.3.3.3 Vegetation Succession .......................................................................................... 39

4.3.3.3 Invasive Plants...................................................................................................... 41

4.3.3 4 Extent of Invasive Pathogens (Condition of Subalpine Vegetation...................... 44

4.3.3.5 Rare Plant Species and Species Diversity............................................................. 45

4.4 Indicators and Criteria to Evaluate Condition and Trends in Vegetation........................ 46

4.3.4.1 Distribution of Stand Age Classes........................................................................ 46

4.3.4.2 Fire Rotations........................................................................................................ 50

4.3.4.3 Changes in Abundance of Major Vegetation Types............................................. 54

4.3.4.4 Invasive Plants...................................................................................................... 62
v

4.3.4.5 Invasive Pathogens................................................................................................ 67

4.3.4.6 Rare Plant Species and Species Diversity............................................................. 68

4.4 Changes in Wildlife ......................................................................................................... 69

4.4.1 Background.............................................................................................................. 69

4.4.2 Regional Context ..................................................................................................... 69

4.4.3 Issues Description .................................................................................................... 69

4.4.3.1 Fire Suppression and Natural Succession............................................................. 69

4.4.3.2 Climate Change, Water, and Snow Pack .............................................................. 70

4.4.3.3 Contaminants........................................................................................................ 70

4.4.3.4 Human Disturbance .............................................................................................. 70

4.4.3.5 Habitat Fragmentation .......................................................................................... 70

4.4.4 Indicators and Criteria to Evaluate Condition and Trends....................................... 70

4.4.4.1 Presence and Persistence of Native Terrestrial Wildlife Species ......................... 71

4.4.4.2 Connectivity and Extent of Important Terrestrial Habitats................................... 79

4.5 Changes in Air Quality .................................................................................................... 81

4.5.1 Background.............................................................................................................. 81

4.5.2 Regional Conditions................................................................................................. 81

4.5.3 Issues Description .................................................................................................... 81

4.5.4 Indicators and Criteria to Evaluate Condition and Trends....................................... 82

4.5.4.1 Atmospheric Nitrogen Deposition ........................................................................ 82

4.5.4.2 Atmospheric Sulfate Deposition........................................................................... 84

4.5.4.3 Airborne Contaminant Deposition........................................................................ 86

4.5.4.4 Ozone .................................................................................................................... 86

4.6 Changes in the Natural Quality of the Park Experience .................................................. 88

4.6.1 Background.............................................................................................................. 88

4.6.2 Regional Context ..................................................................................................... 88

4.6.3 Issue Description...................................................................................................... 88
vi

4.6.4 Indicators and Criteria to Evaluate Condition and Trends....................................... 88

4.6.4.1 Disturbed Area Recovery...................................................................................... 88

4.6.4.2 Visibility ............................................................................................................... 89

4.6.4.3 Dark Night Sky ..................................................................................................... 91

4.6.4.4 Soundscape ........................................................................................................... 92

4.6.4.5 Physical Remoteness and Solitude........................................................................ 93

5.0 Discussion............................................................................................................................... 95

6.0 Literature Cited ....................................................................................................................... 99
vii

Figures

Page

Figure 1. Location map for Lassen Volcanic National Park.......................................................... 6

Figure 2. Base map for Lassen Volcanic National Park. ............................................................... 7

Figure 3. Watersheds of Lassen Volcanic National Park............................................................. 12

Figure 4. Average daily flow 1927 to 1994 at Hat Creek............................................................ 21

Figure 5. Dates of springtime peak flow, 1927 to 1994 at Hat Creek. Hat Creek 

originates within the park but these measurements are from a stream gauge located 

outside the park............................................................................................................................. 22

Figure 6. Human influences on the structure, function, and composition of 

ecosystems. ................................................................................................................................... 35

Figure 7. Hypothetical changes in the amount of higher and lower severity fire with 

fire suppression where a low-severity fire regime and steady-state conditions 

historically occurred...................................................................................................................... 37

Figure 8. Changes in the amount of higher and lower severity fire with fire 

suppression under a historical model of mixed severity fire. ....................................................... 38

Figure 9. Non-Native Plant Species Richness as a Function of Park Area and 

Elevation in the Klamath Network. .............................................................................................. 42

Figure 10. Theoretical stand age distribution in forests affected by a low-severity fire 

regime and an increase in susceptibility to more severe fire in recent decades due to 

fire suppression. ............................................................................................................................ 47

Figure 11. Hypothetical stand age distribution for forests affected by a mixedseverity fire regime and 70-90 years of reduced fire due to fire suppression............................... 47

Figure 12. Never-managed forest stand age distribution in the upper montane zones 

of the eastern Cascades (black bars), compared with the theoretical distribution that 

would be present had pre-suppression fire disturbances not been interrupted by fire 

suppression (gray bars). ................................................................................................................ 49

Figure 13. The VTM map for Lassen (circa 1930) and the current vegetation map. 

Both have been crosswalked to a common cover type classification. .......................................... 55

Figure 14. Historic distribution of aspen- (Populus tremuloides) dominated forests at 

Lassen as depicted in VTM mapping, and current distribution. Arrows help point out 

the current distribution.................................................................................................................. 59

Figure 15. Historic distribution of red and white fir (Abies magnifica and A. 

concolor) dominated forests at Lassen as depicted in VTM mapping, and current 

distribution of forests dominated by these species. ...................................................................... 61
viii

Figures (continued)

Page

Figure 16. Locations of infestations and all sampling locations (n=1050) at Lassen 

from the two vegetation sampling databases and the wetlands assessment database................... 63

Figure 17. Locations of invasive species found during the Klamath Network 

Monitoring in 2011. The green lines show the routes that were surveyed. .................................. 65

Figure 18. Conceptual model of an invasive species early detection program and the 

feedbacks with management (From Odion et al. 2010a). ............................................................. 67

Figure 19. Predicted habitat suitability for American marten in the vicinity of the 

park (from Zielinski et al. 2005)................................................................................................... 73

Figure 20. Number of bird species found on the annual Breeding Bird Survey route 

through the park, 1972-2009......................................................................................................... 77

Figure 21. Number of individual birds found on the annual Breeding Bird Survey 

route through the park, 1972-2009. The model is: R2

=0.1458, p=0.0259, slope=-

1.7936, n=34. ................................................................................................................................ 77

Figure 22. Essential Connectivity Areas as mapped by CDFW (2013b) in the vicinity 

of the park. .................................................................................................................................... 80

Figure 23. Nitrate deposition at Lassen Volcanic National Park, 1988-2010. 

(IMPROVE web site: http://views.cira.colostate.edu/web )......................................................... 83

Figure 24. N-deposition at Lassen Volcanic National Park, 1996-2010. (CASTnet).................. 83

Figure 25. Sulfate deposition at Lassen Volcanic National Park, 1988-2010. Source: 

IMPROVE web site http://views.cira.colostate.edu/web.............................................................. 85

Figure 26. Sulfate deposition at Lassen Volcanic National Park, 1996-2010. Source: 

CASTnet. ...................................................................................................................................... 85

Figure 27. Visibility (in deciview units) from the park, 1988-2005. (IMPROVE web 

site: http://views.cira.colostate.edu/web )..................................................................................... 91
ix

Tables

Page

Table 1. The range of projected changes to the climate (including temperature and 

precipitation) and ecology (dominant vegetation types, fire regime) of the Klamath 

Basin from three global climate models and a vegetation model ................................................. 15

Table 2. Average annual snowfall at Lassen associated with ENSO conditions, 1950-

2005 (from Andalkar 2005b). ....................................................................................................... 18

Table 3. Comparison of water samples from Lassen with USEPA thresholds for 

potential harm to aquatic life ........................................................................................................ 28

Table 4. Area of broad vegetation types in Lassen. ..................................................................... 36

Table 5. Invasive plants of greatest concern at Lassen National Monument as 

determined by the prioritization process used by the Klamath Network and involving 

park resource staff (Odion et al. 2011) ......................................................................................... 43

Table 6. Equilibrium species in Lassen Volcanic National Monument and status of 

species which will or will not be monitored in the backcountry by the Klamath 

Network Inventory and Monitoring Program. .............................................................................. 44

Table 7. Vegetation indicators and the ecological conditions for which they are 

indicators....................................................................................................................................... 46

Table 8. Mean fire frequency prior to fire suppression from studies in the northern 

Sierra Nevada and southern Cascades. ......................................................................................... 52

Table 9. Fire rotations from studies of small landscapes in the southern Cascades 

adjacent to Lassen National Park.................................................................................................. 53

Table 10. Changes in area of broad vegetation types in Lassen Volcanic National 

Park, circa 1930 to present............................................................................................................ 57

Table 11. Species found in 1050 vegetation sampling plots from 2007-2010 in Lassen 

National Park. ............................................................................................................................... 64

Table 12. Species with statistically significant increase or decrease on the annual 

Breeding Bird Survey Route through the park, 1972-2009 .......................................................... 78

Table 14. Summary of ratings for indicators of natural resource condition and trend 

used in this analysis of Lassen Volcanic National Park ............................................................... 96

xi

Appendices

Page

Appendix A. Climate of Lassen Volcanic National Park supporting data and maps................. A-1

Appendix B. Physical Characteristics of Lassen Volcanic National Park: supporting 

data and maps.............................................................................................................................. B-1

Appendix C. Vegetation and Fire-related Characteristics of Lassen Volcanic National 

Park: supporting data and maps.................................................................................................. C-1

Appendix D. Vertebrates of Lassen Volcanic National Park ..................................................... D-1

xiii

Executive Summary

We compiled existing data and information to characterize the condition and trends in priority 

natural resources in Lassen Volcanic National Park. This report and the spatial datasets provided 

with it is intended to inform and support park managers and scientists in developing 

recommendations for improving or maintaining natural resource conditions in the park. It also 

can assist park resource managers in meeting the reporting requirements of the Government 

Performance Results Act and Office of Management and Budget.

In attempts to describe the current condition and trends for the park’s natural resources of 

concern, we followed generally the Environmental Protection Agency’s “Framework for 

Assessing and Reporting on Ecological Condition” (Young and Sanzone 2002). Specifically, we 

first identified six natural resource themes considered by this park’s managers and scientists to 

be most important. They are:

• Precipitation, Snowpack, and Water Availability

• Surface Waters and Their Resources

• Terrestrial Vegetation

• Wildlife

• Air Quality

• Natural Quality of the Park Experience

We identified 23 indicators to evaluate these six resource concerns. For each indicator we then 

attempted to define reference conditions to which we could compare present conditions. Making 

that comparison, we described the condition of each indicator as “Good,” “Somewhat 

Concerning,” “Significant Concern,” or “Indeterminate.” We described the indicator’s trend as 

“Improving,” “Somewhat Concerning,” “Significant Concern,” or “Indeterminate.” In each 

instance where we applied these terms, we also described (as high, moderate, or low) the 

certainty associated with our estimate. Where reference conditions that were the basis for our 

comparisons lacked quantitative standards, we based the assessment on qualitative descriptions 

of least-altered resource conditions derived from historical accounts, scientific literature, and 

professional opinion. 

Applying the 23 indicators, we determined that the condition of three indicators is of “Significant 

Concern” in this park. Those are: the distribution of forest stand ages, deposition of airborne 

contaminants, and ozone damage to vegetation. There is little that park managers can do to 

control the latter two. However, NPS has had some success working with policy makers and 

regulators to enforce stricter standards when park data indicated air quality problems resulting 

from local sources.With regard to the distribution of forest stand ages, the reduced frequency of

fire in some parts of the park has created conditions that are at the extreme end of the natural age

distribution for the park’s vegetation types. This can restrict the park’s ability to effectively 

support the region’s wildlife and plant diversity.
xiv

We assigned a rating of “Somewhat Concerning” to eight indicators: 

• Recovery of human-disturbed areas

• Diversity of native aquatic species

• Distributions of major vegetation types

• Extent of invasive plant species

• Extent of exotic pathogens

• Visibility

• Timing and rate of spring snow melt and discharge in springs and streams

• Maximum annual depth and volume of snowpack by location

Park managers have limited capacity to influence the condition of the last four. However, NPS 

has had some success working with policy makers and regulators to enforce stricter standards 

when park data indicated air quality problems resulting from local sources.

The condition of a plurality of the indicators (10) was rated “Good.” However, information was 

insufficient to rate the present condition or trends of four very important indicators:

• Maximum annual extent, depth, and volume of snowpack

• Timing and rate of spring melt and discharge in springs and streams

• Perennial stream extent, seasonal flow volume, wetted width

• Water bodies with ecologically harmful species

Information sufficient to estimate trends was lacking for 12 of the 23 indicators, and none were

considered to have a high degree of certainty.
xv

Acknowledgments

For their steadfast interest in this assessment and helpful suggestions, we thank Daniel Sarr 

(NPS, Klamath Network I&M Program’s Supervisory Ecologist) and Marsha Davis (NPS Pacific

West Regional Office). For their excellent input at several points during preparation of this 

assessment, from Lassen Volcanic National Park we thank Jennifer Carpenter (Chief of Resource

Management), Louise Johnson (formerly, Chief of Resource Management), Nancy Nordensten

(formerly, Resource Management Specialist), Janet Coles (Plant Ecologist), and Mike Magnuson 

(Wildlife Biologist). Overall guidance was provided by the NPS Project Managers—initially 

David Larson from Lava Beds National Monument, succeeded by Mac Brock of Crater Lake 

National Park.

Prologue

Publisher’s Note: This report is part of an ongoing series of natural resource condition 

assessments in national park units. As a point of clarification, this document does not follow the 

standard report outline that the National Park Service (NPS) has established for the series. 

However, the condition assessment methodologies and reporting details found in chapter 4—the 

“core section” of the report—do conform to NPS guidelines.

1

1.0 NRCA Background

What is the current condition of natural resources in our nation’s national parks? How has that

condition changed in recent years? What might be the actual and potential causes of current and

future change? This report, prepared under a National Park Service (NPS) agreement with

Southern Oregon University (SOU), focuses on these questions as they pertain to Lassen 

Volcanic National Park.

Addressing these questions is essential to the mission of the NPS. Thus, the NPS in 2003

initiated overview assessments of each of 270-plus parks which NPS deemed to have significant

natural resources and related values. Those assessments, termed “Natural Resource Condition

Assessments” (NRCAs), focus on compiling and interpreting existing data, and are intended to

complement Inventory and Monitoring (I & M) programs and other efforts that feature the

collection of new data. Both programs complement and help support each park’s development of

a Resource Stewardship Strategy (RSS)1

and State of the Park Report, which focuses instead on

management targets and provides guidance on how to respond to and manage threats. NRCAs 

rely significantly on review and syntheses of existing data and maps, as contrasted with the NPS 

Vital Signs Program which mainly features the collection of new field data.

NRCAs evaluate current conditions for a subset of natural resources and resource indicators. 

NRCAs also report on trends in resource condition (when possible), identify critical data gaps,

and characterize a general level of confidence for study findings. The resources and indicators

emphasized in a given project depend on the park’s resource setting, status of resource

stewardship planning and science in identifying high-priority indicators, and availability of data

and expertise to assess current conditions for a variety of potential study resources and

indicators.

NRCAs represent a relatively new approach to assessing and reporting on park resource

conditions. They are meant to complement—not replace—traditional issue- and threat-based

resource assessments. As distinguishing characteristics, NRCAs:

• are multi-disciplinary in scope;

2

• employ hierarchical indicator frameworks;

3

 

1 formerly called a Resource Management Plan (RMP).

2 The breadth of natural resources and number/type of indicators evaluated will vary by park. 

3 Frameworks help guide a multi-disciplinary selection of indicators and subsequent “roll up” and reporting 

of data for measures  conditions for indicators  condition summaries by broader topics and park areas 
2

• identify or develop reference conditions/values for comparison against current

conditions;

4

• emphasize spatial evaluation of conditions and GIS (map) products;

5

• summarize key findings by park areas; and6

• follow national NRCA guidelines and standards for study design and reporting products. 

Although the primary objective of NRCAs is to report on current conditions relative to logical 

forms of reference conditions and values, NRCAs also report on trends, when appropriate (i.e., 

when the underlying data and methods support such reporting), as well as influences on resource

conditions. These influences may include past activities or conditions that provide a helpful

context for understanding current conditions, and/or present-day threats and stressors that are

best interpreted at park, watershed, or landscape scales (though NRCAs are not required to report

on condition status for land areas and natural resources beyond park boundaries). Intensive

cause-and-effect analyses of threats and stressors, and development of detailed treatment options, 

are outside the scope of NRCAs.

Due to their modest funding, relatively quick timeframe for completion, and reliance on existing

data and information, NRCAs are not intended to be exhaustive. Their methodology typically

involves an informal synthesis of scientific data and information from multiple and diverse

sources. Level of rigor and statistical repeatability will vary by resource or indicator, reflecting

differences in existing data and knowledge bases across the varied study components.

The credibility of NRCA results is derived from the data, methods, and reference values used in

the project work, which are designed to be appropriate for the stated purpose of the project, as 

well as adequately documented. NRCAs can yield new insights about current park resource

conditions but, in many cases, their greatest value may be the development of useful

documentation regarding known or suspected resource conditions within parks. Reporting

products can help park managers as they think about near-term workload priorities, frame data

and study needs for important park resources, and communicate messages about current park

resource conditions to various audiences. A successful NRCA delivers science-based

information that is both credible and has practical uses for a variety of park decision-making,

planning, and partnership activities.

 

4 NRCAs must consider ecologically-based reference conditions, must also consider applicable legal and 

regulatory standards, and can consider other management-specified condition objectives or targets; each 

study indicator can be evaluated against one or more types of logical reference conditions. Reference 

values can be expressed in qualitative to quantitative terms, as a single value or range of values; they 

represent desirable resource conditions or, alternatively, condition states that we wish to avoid or that 

require a follow-on response (e.g., ecological thresholds or management “triggers”).

5 As possible and appropriate, NRCAs describe condition gradients or differences across a park for 

important natural resources and study indicators through a set of GIS coverages and map products. 

6 In addition to reporting on indicator-level conditions, NRCAs attempt to take a bigger picture (more 

holistic) view and summarize overall findings and provide suggestions to managers on an area-by-area 

basis: 1) by park ecosystem/habitat types or watersheds, and 2) for other park areas as requested.
3

However, it is important to note that NRCAs do not establish management targets for study

indicators. That process must occur through park planning and management activities. What an 

NRCA can do is deliver science-based information that will assist park managers in their 

ongoing, long-term efforts to describe and quantify a park’s desired resource conditions and

management targets. In the near term, NRCA findings assist strategic park resource planning7

and help parks to report on government accountability measures.

8 In addition, although in-depth

analysis of the effects of climate change on park natural resources is outside the scope of 

NRCAs, the condition analyses and data sets developed for NRCAs will be useful for park-level

climate-change studies and planning efforts. For more information on the NRCA program, visit 

http://nature.nps.gov/water/nrca/index.cfm

 

7 An NRCA can be useful during the development of a park’s Resource Stewardship Strategy (RSS) and 

can also be tailored to act as a post-RSS project.

8 While accountability reporting measures are subject to change, the spatial and reference-based 

condition data provided by NRCAs will be useful for most forms of “resource condition status” reporting as 

may be required by the NPS, the Department of the Interior, or the Office of Management and Budget. 

5

2.0 Introduction and Resource Setting

Lassen Volcanic National Park (“the park”) is located in northeastern California in portions of

Lassen, Plumas, Shasta, and Tehama counties and is roughly 50 miles east of both Red Bluff and 

Redding, California (Figures 1, 2). The park encompasses 106,372 acres and is almost

completely surrounded by Lassen National Forest. The park was established by an Act of

Congress on August 9, 1916, to provide recreational opportunities for the public and to preserve

its natural wonders and resources. In 1972, Congress designated 75 percent of the park (78,982

acres) as the Lassen Volcanic Wilderness. The park is a high elevation island with elevations 

ranging from 5,250 to 10,457 feet, while only a few isolated peaks in the surrounding area rise 

above 6,000 feet. Topography within the park varies greatly with rugged, volcanic mountain

peaks in the western section; a lava plateau in the east; deep glaciated valleys and several 

geothermal features in the south; and peaks and ridges of lava modified by erosion in the north.

The park is an outstanding example of a dynamic geologic landscape. Lassen Peak is the

southernmost active volcano in the Cascade Mountain Range and erupted intermittently between

1914 and 1921. The park is unique in that it preserves examples of all four types of volcanoes

recognized by geologists: shield, composite, plug dome, and cinder cone volcanoes. Lassen Peak

is one of the largest plug dome volcanoes in the world. Also within the park is the most

extensive, intact network of geothermal resources west of Yellowstone National Park, including

examples of boiling springs, mudpots, and fumaroles. The numbers and variety of small ponds 

and wetlands are also exceptional for northern California.

Park soils are generally rocky, shallow, rapidly drained, and strongly acidic. They are almost

exclusively volcanic in origin. Soil depths vary from several feet in some lower elevation

meadows to thin or nonexistent on the higher elevations.

Four general vegetation types cover most of the park from lower to higher elevations: yellow

pine forests, red fir forests, subalpine forests dominated by whitebark pine and mountain

hemlock, and alpine fell fields. Patches of montane chaparral dominated by greenleaf manzanita

(Arctostaphylos patula), snowbrush ceanothus (Ceanothus cordulatus), or pinemat manzanita

(Arctostaphylos nevadensis) cover approximately 10% of the park. Most of these shrub fields

became established after high intensity fires and are gradually being recolonized by conifers.

Willow, alder, and meadow vegetation grow along many of the streams and aspen is found in

several moist riparian zones and upland habitats. A large area of the park is rocky and relatively

devoid of vegetation.
6

Figure 1. Location map for Lassen Volcanic National Park
7

Figure 2. Base map for Lassen Volcanic National Park.

9

3.0 Study Scoping, Design, and Implementation

3.1 Project Responsibilities

Co-investigators for this project were Dr. Greg Jones, climatologist, Southern Oregon 

University, and Dr. Paul Adamus, ecologist, Oregon State University. Dr. Jones administered the 

agreement and analyzed climatological data. Dr. Adamus served as report editor as well as 

writing all sections except section 2.3 which addresses vegetation and fire regime. That section 

was prepared by Dennis Odion, vegetation ecologist, Southern Oregon University. A supporting 

analysis of changes in vegetation distribution based on historical maps was done by Dr. James 

Thorne of the University of California, Davis. Spatial data were compiled and analyzed by Ryan 

Reid and Lorin Groshong (GIS specialists, Southern Oregon University) with substantial input 

from other members of the project team.

3.2 Framework and Information Gathering

This assessment is one of three NRCAs prepared under a single agreement with Southern Oregon

University. The others pertain to Lava Beds National Monument (LABE) and Crater Lake

National Park (CRLA). The assessments began in October 2010 with a scoping workshop that

included the SOU study team, most members of the NPS Project Oversight Committee9, and

other scientists from the three parks being assessed. Held at the Lava Beds headquarters near

Tulelake, California, the session began with a background description of the NRCA process

presented by Marsha Davis from the NPS Pacific West Regional Office, followed by

presentations by the project co-principal investigators and others, and a group discussion

focusing on project frameworks and strategy. Then the team traveled to Lassen and sought

information from several scientists there.

Natural resource issues in the park had recently been prioritized by the park’s staff, using a

structured input process, and that was a great help in focusing our efforts. In no particular order, 

the 15 “focal themes” that were ranked highest (3 on a scale of 0 to 3) from a list of 56 themes 

considered potentially applicable to the three Klamath Network parks that are the subject of this 

SOU agreement were: 

• Lakes and streams

• Wetlands and riparian areas

• Groundwater flow

• Geologic and geothermal resources

• Fire regimes

 

9 From Lassen: Louise Johnson (formerly, Chief of Resources), Nancy Nordensten (formerly, Resource 

Management Specialist; Biologist), Janet Coles (Plant Ecologist). From CRLA: Mac Brock (Chief of 

Resources Management and NRCA Project Manager), Jeff Runde (Resource Management Specialist 

and Data Manager), Chris Wayne (GIS Specialist). From Lava Beds National Monument: David Larson 

(formerly, Chief of Resource Management and NRCA Project Manager), Jason Mateljak (Resource 

Management Specialist), Shane Fryer (Physical Scientist). From Pacific West Regional Office: Marsha 

Davis (Geologist).
10

• Fire suppression and fuels management

• Invasive species (plants)

• Phenological cycles

• Solitude and silence

• Dark night sky

• Recreation

• Wilderness

• Deposition of airborne contaminants

• Moisture and climate cycles

• Global warming

More specifically, the issues mentioned as being of greatest concern in Lassen were:

• Climate change and its impacts on high elevation ecosystems 

• Changes in the timing and extent of snowpack 

• Condition of primary lake areas (e.g., Summit and Manzanita) 

• Overall condition of high elevation meadow and riparian systems 

• Effects of atmospheric deposition on park ecosystems 

• Condition of forest health and function 

In addition, indicators of natural resource condition had recently been identified through the

Klamath Network’s Vital Signs planning process. Some of that information was used to target

indicators pertinent to our NRCA effort. Lassen’s 1999 Resource Management Plan (NPS 1999) 

provided useful background information, as did, to a lesser degree, the “State of the Park Report” 

(NPCA 2009) and the General Management Plan (NPS 2003).

The task of identifying documents important to understanding these issues was made easier by

the Klamath Network having recently completed a “data mining” report. That report was

accompanied by a bibliographic database of nearly all published and unpublished documents and

maps for these parks, up to about 2007. We augmented that using online search engines (Web of

Science, Google Scholar) to identify newer publications related to Lassen, as well as relevant

documents pertaining to the regions surrounding the park, searching with phrases such as

“Southern Cascades,” “northern Sierra Nevada,” “Lassen National Forest,” “Lassen County,” 

and “Caribou Wilderness.” We obtained complete digital copies (PDFs) of all available

publications that reported relevant research results from the park and the surrounding region. We 

then indexed the digital documents in an Excel spreadsheet so they could be sorted by topic and

year. The database and all the digital documents, as well as spatial data layers, were placed on a

server computer at SOU that was accessible to the project team and park staff.

We reviewed and considered several frameworks for organizing our NRCA effort. We decided to 

follow generally the Environmental Protection Agency’s “Framework for Assessing and 

Reporting on Ecological Condition” (Young and Sanzone 2002). Specifically, for each priority 

resource we identified multiple indicators of resource condition and defined reference conditions 

that could be used as a basis for assessing these. An ecological indicator is any measurable

attribute that provides insights into the state of the environment and provides information beyond

its own measurement (Noon 2003). Indicators are usually surrogates for properties or system
11

responses that are too difficult or costly to measure directly. Indicators differ from estimators in

that functional relationships between the indicator and the various ecological attributes are

generally unknown (McKelvey and Pearson 2001). Not all indicators are equally informative—

one of the key challenges of an NRCA is to select those attributes whose values (or trends)

provide insights into ecological integrity at the scale of the ecosystem.

In developing the list of indicators and specific measures, we considered some basic criteria for

useful ecological indicators as provided by Harwell et al. (1999). “Useful indicators need to be

understandable to multiple audiences, including scientists, policy makers, managers and the

public; they need to show status and/or condition over time; and there should be a clear,

transparent scientific basis for the assigned condition.” Indicators need to be based on probability

distributions whenever possible to capture the natural range of variation in conditions, and we

have attempted to do that whenever possible. We evaluated the indicators we chose by assigning

qualitative descriptors as follows:

Condition: Good, Somewhat Concerning, Significant Concern, or Indeterminate.

Trend: Improving, Somewhat Concerning, Significant Concern, or Indeterminate.

Certainty: High, Medium, or Low.

We defined these terms in the context of each specific resource or issue we evaluated. Most 

indicators were assessed at the park scale, although connections to regional conditions were 

noted where supported by previously published analyses. The maps prepared for this assessment 

potentially reveal differences in resources at a finer scale within the park. Watersheds (Figure 3) 

were used as the “analysis units.” The four major watersheds that the park intersects are:

• Battle Creek Watershed

• Lower Pit-Honey Eagle Lakes Watershed

• North Fork Feather Watershed

• Thomas Creek-Sacramento River Watershed
12

Figure 3. Watersheds of Lassen Volcanic National Park.
13

4.0 Natural Resource Conditions and Trends

According to park staff, the greatest concerns regarding the natural resources at Lassen, in no

particular order, are currently:

1. Changes in the extent of montane snowpack and the timing of water availability, as

possibly affected by global or regional climate change.

2. Changes in condition and distribution of high elevation lake, wetland, meadow, and

riparian systems as a result of climate change, recreational use, invasive plants, and

deposition of airborne particulates, nutrients, and contaminants.

3. Changes in the condition, distribution, diversity, and connectivity of vegetation types

and their associated wildlife, as potentially affected by fire suppression, fuels

management, insects, disease, climate change, air pollution, and invasive species.

4. Recovery rate of soils and vegetation on disturbed lands, such as those in Warner

Valley and in places where trespassing cattle, unauthorized trails, other human activities

(including those from before the park was established) may have caused impacts.

5. The overall natural quality of the park experience, as reflected by physical remoteness,

quiet, and unobscured night sky.

Each of those natural resource concerns is now described using the following structure:

• Background

• Regional Context

• Issue Description

• Indicators and Criteria to Evaluate Condition and Trends:

Criteria

Condition and Trends

Assessment Confidence and Data Gaps

4.1 Changes in Precipitation, Snowpack, and Water Availability

4.1.1 Background

Precipitation and snowpack are essential for supporting forests and wildlife, sustaining stream

flow and water table levels that feed ponds, lakes, and wetlands, and for reducing fire risk. Long

term changes in air temperatures can affect precipitation and snowpack in several ways. First, 

warming winter (November – March) temperatures influence the proportion of precipitation that

falls and is retained longer in the season as snow. Snow depth affects the overwinter survival and

springtime germination of plants and emergence of insects, as well as wildlife movements, 

breeding success, and the availability of shelter. Second, the timing and speed of snowmelt are 

sensitive to changes in springtime temperatures (Knowles et al. 2006). Snowmelt water helps

sustain public and private water supplies in drier low-elevation lands. When snowpack melts

quickly, the period when side channel and floodplain habitats are inundated by water is shorter,

limiting the habitat for fish and other aquatic animals. Decreased flows during late spring,

summer, and early fall coupled with rising air temperatures are likely to increase water
14

temperatures, reducing habitat suitability for native coldwater fish (Barr et al. 2010). Under

normal circumstances, because water is released from melting snow more gradually than from

rainfall, water infiltration into soils and groundwater is more complete. Consequently, stream

flow is sustained longer into the growing season and natural processes may have longer to

detoxify any pollutants present in precipitation and snow pack. However, warming trends may

cause less nitrate to be exported from melting snow because soil microbial and plant uptake

processes that effectively remove nitrate may be activated earlier in the season (Sickman et al. 

2003).

For Lassen, long-term precipitation and temperature averages are shown in Appendix A. In

general, the amount of precipitation decreases in an easterly direction from Lassen Peak due

mainly to the rain shadow effect of the western Sierra Nevada and Cascade Ranges. Most

precipitation occurs from November to April, and snow accumulates mainly from December to

March. Below 6000 feet in elevation, a larger proportion of the annual precipitation occurs as

rain.

4.1.2 Regional Context

No other areas in the immediate vicinity of Lassen support a year-round snow pack. The closest 

such area is Mount Shasta, located 70 miles to the northwest. Climate projections for the 

Klamath Region as a whole (Barr et al. 2010) are shown in Table 1.
15

Table 1. The range of projected changes to the climate (including temperature and precipitation) and

ecology (dominant vegetation types, fire regime) of the Klamath Basin from three global climate models

and a vegetation model. Baseline conditions are based on data from 1961-1990. Snowpack projections

are based on results from supporting studies (Hayhoe et al. 2004; Goodstein and Matson 2004).

Projected Average Annual and Seasonal Temperature Increase from Baseline

2035 - 2045 2075 - 2085

Annual

June – August

December – February 

+2.1 to +3.6° F (+1.1 to +2.0° C)

+2.2 to +4.8° F (+1.2 to 2.7° C)

+1.7 to +3.6° F (+1.0 to 2.0° C)

+4.6 to +7.2° F (+2.5 to +4.6° C)

+5.8 to +11.8° F (+3.2 to +6.6° C)

+3.8 to +6.5° F (+2.1 to +3.6° C)

Projected Average Annual and Seasonal Change in Precipitation from Baseline

Annual

June – August

December - February

-0.27 to +0.07 inch (-9 to +2 %)

-0.16 to +0.11 inch (-15 to -23 %)

+0.06 to +0.57 inch (+1 to +10 %)

-0.33 to +0.74 inch (-11 to +24 %)

-0.25 to +1.00 inch (-37 to -3 %)

-0.28 to +1.59 inch (-5 to +27 %)

Projected Percent Change in Area Burned on Annual Basis Compared to Baseline

Area Burned +13 to 18% +11 to 22%

Projected Change in Vegetation Growing Conditions from Baseline

Vegetation Growing

Conditions

Complete loss of subalpine.

Partial loss of maritime conifer

(Douglas-fir and spruce).

Expansion of oak and madrone.

Partial to complete loss of maritime

conifer

Expansion of oak and madrone.

Possible replacement of sagebrush

and juniper with grasslands.

Projected Change in Snowpack from Baseline

Snowpack Loss of 37 to 65% Loss of 73 to 90%

4.1.3 Issues Description

4.1.3.1 Historical Climate Change

In western North America generally, during the twentieth century the winter and spring

temperatures increased (Mote et al. 2005). The rate of change varied by location, but generally a 

warming of 1°C occurred between 1916 and 2003 (Hamlet et al. 2007). The rate of temperature 

increase from 1947 to 2003 was roughly double that averaged for the entire period from 1916 to 

2003. This was largely attributable to the fact that much of the observed warming occurred from 

1975 to 2003. Regionally averaged spring and summer temperatures for 1987 to 2003 were 

0.87°C higher than those for 1970 to 1986, and spring and summer temperatures for 1987 to 

2003 were the warmest since the beginning of the record in 1895 (Westerling et al. 2006). The 

largest warming trends have occurred in January-March (Hamlet and Lettenmaier 2007). 
16

The snowpack has declined over much of the West (Mote 2003a, 2003b) despite increases in 

winter precipitation in many places. The largest reductions have occurred where winter 

temperatures are mild, especially in the Cascade Mountains (where estimates of April 1 snow 

water equivalent indicate a 15–35% decline from mid-century to 2006) and in northern 

California. In most mountain ranges, snowpack has changed little at the highest elevations but 

major declines have occurred at lower elevation snow lines (Mote et al. 2005, Mote et al. 2008a). 

A shift in the timing of springtime snowmelt towards earlier in the year also has been observed 

during 1948–2000 in many western rivers. The shift has been attributed to more precipitation 

falling as rain rather than snow and earlier snowmelt (Knowles et al. 2006). In the Sierra Nevada,

the last several decades were among the warmest of the last millennium (Graumlich 1993). In the

Pacific Northwest, the snow water equivalent (i.e., the depth of water equivalent to the weight of

the snowpack) decreased over the period 1950–2000, and is related to increases in temperature

(Mote 2003a). 

4.1.3.2 Future Climate Change

For the western U.S., predictive models of future climate indicate that average temperatures will 

likely increase in both winter and summer (Giorgi et al. 2001). The average warming rate in the 

Pacific Northwest during the next ~50 years is expected to be in the range 0.1-0.6°C per decade, 

with a best estimate of 0.3°C per decade. For comparison, observed warming in the second half 

of the century was approximately 0.2°C per decade (Mote et al. 2008b). In the Sierra Nevada, by 

the years 2050 to 2100, average annual temperature could increase by as much as 3.8oC (6.8oF) 

(Snyder et al. 2002). This is the equivalent of about an 800 m upward displacement in climatic

zones. Average temperatures in May could increase by 9 oC. Even a relatively modest mean

temperature increase (2.5°C) would significantly alter precipitation, snow pack, surface water

dynamics (e.g., flow), and hydrologic processes in the Sierra Nevada.

The most pronounced changes would probably be a lower snowpack volume at mid-elevations 

(Knowles and Cayan 2001). Two climate models predict significant reductions in Sierra Nevada 

snowpack by the year 2100: one model predicts 30–70% reduction, the other a 73–90% 

reduction (Hayhoe et al. 2004). Also, the snowmelt runoff would occur earlier (Hamlet and 

Lettenmaier 2007, Jeton et al. 1996, Kim 2005, Kim et al. 2002, Leung et al. 2004), summer base 

flows and soil moisture would be reduced, and winter and spring flooding might increase. In 

California, a larger proportion of the streamflow volume would occur earlier in the year. In 

snowmelt-driven basins, late winter snowpack accumulation will decrease by 50% toward the 

end of this century (Miller et al. 2003). For the Klamath Network region specifically, simulations 

indicate future decreases in snow (e.g., Leung et al. 2004) and changes in the timing of snowmelt 

runoff (e.g., Stewart et al. 2004, 2005). Projections of future changes in Sierra Nevada climate 

related to precipitation quantity are less certain (Howat and Tulaczyk 2005), but precipitation is 

simulated to increase in winter, while summer-drought conditions will become more severe 

(Dettinger 2005, Dettinger et al. 2005, Mote et al. 2005).

4.1.4 Indicators and Criteria to Evaluate Condition and Trends

Although little or nothing can be done within the park to address changes in precipitation,

snowpack, and water availability, improved knowledge of current conditions and anticipated

changes can help resource planning efforts. Indicators that would inform this issue might include

the condition and trends of the following, with the goal of maintaining conditions within the

usual range of interannual variation:
17

1. Maximum annual extent, location, and depth of snow pack

2. Volume, timing, and rate of spring melt

3. Seasonal flow volumes, wetted width and length, and seasonal timing of discharge in

all of the park’s springs and streams

4. Number, area, depth, and seasonal persistence of the park’s wetlands, ponds, and lakes

These have not been comprehensively documented, and existing data from the park are

insufficient to determine past or likely future trends. Locations of various types of weather 

instruments in or near the park were mapped and described in Davey et al. (2007) and Daly et al. 

(2009). The latter report describes results of a statistical analysis whose purpose was to

investigate possible long-term trends in air temperature and precipitation. No data are available

that quantify snow pack extent (not just depth) or spring melt conditions, nor flow characteristics

in the 12 perennial and many ephemeral streams before they exit the park. The areas of most of

the park’s wetlands, ponds, and lakes are known and should be re-measured with updated aerial

imagery at intervals of one decade or less, depending on apparent rates of climate change.

However, interannual and seasonal differences in precipitation, wind, and temperature would 

first need to be ruled out if detection of long-term change is the objective.

4.1.4.1 Maximum Annual Depth and Volume of Snowpack by Location

Criteria 

Local and regional data on snow amounts are insufficient to quantify reference conditions 

appropriate for this park, so qualitative statements will define the reference conditions. “Good” 

condition would be represented by the amount (depth, extent, volume) of snowpack needed to

sustain conditions close to the average historical condition in all parts of the park, and especially 

at higher elevations because of their importance in sustaining streams, ponds, and wetlands 

throughout lower portions of the park. “Somewhat Concerning” would be snowpack that is less 

than historical condition but still supports most of the park’s key ecological processes and natural 

resources. “Significant Concern” would be snowpack that is insufficient to support those. 

Condition 

Indeterminate. Despite a relative abundance of snow depth measurements from in or near the 

park, condition is rated “Indeterminate” because the annual depth and volume of snowpack 

which comprise “normal” conditions for sustaining within the park has not been determined.

Snow depth has been monitored at Manzanita Lake (since 1949), Lake Helen (since 1930), 

Lassen Chalet (since 1986), and at four sites outside but near the park: Harkness Flat (since 

1930), Feather River Meadow (since 1930), Mineral (since 1948), and Chester (since 1948). The 

Lake Helen site has the most snow of any place in California, with an April 1 average of 178 

inches, a maximum of 331 inches, and a minimum of 64 inches (Andalkar 2005b). Snow depth 

tends to be greater in the southern parts of the park and at higher elevations.

The El Niño/La Niña Southern Oscillation (ENSO) weather phenomena clearly influence the

amount of snowfall in the park. During the years since record-keeping began in 1949, when there 

were strong El Niño conditions, snowfall in the northern California Cascades was 10-40% above 

normal. When there were strong La Niña conditions, snowfall was 5-15% above normal. When 
18

there were weak El Niño or weak La Niña conditions, snowfall was 5-15% below normal 

(Andalkar 2005b). Snow depths associated with these conditions are shown in Table 2. 

Table 2. Average annual snowfall at Lassen associated with ENSO conditions, 1950-2005 (from Andalkar 

2005b).

Condition

Annual Snowfall (inches)

Manzanita Lake

(elevation= 5900 ft)

Lassen Chalet

(elevation= 6700 ft)

Mineral

(elevation= 4900 ft)

Strong El Niño 203 515 160

Weak El Niño 204 396 162

Neutral 171 387 142

Weak La Niña 179 374 145

Strong La Niña 207 451 161

Average 189 429 152

Maximum 328 712 309

Minimum 76 230 71

Trends

Somewhat Concerning – Low Certainty. Analysis of the climate data possibly suggests a 

warming trend and no clear trend in annual precipitation. Snowpack depth and volume depend 

on coincidence of increased precipitation with cooler temperatures. Analyses of trends in this 

specific pairing would not be meaningful because available data are only from lower elevations 

within the park. Only the data from the Manzanita Lake monitoring site are sufficiently detailed 

and complete to calculate trends in this indicator directly. From 1949 to 2007, a statistically 

significant decline occurred in the April 1 snow depth at that site (Daly et al. 2009). The winter 

(January-March) snow depth showed no statistically significant trend during that period. The 

ecological significance of a snowpack trend that is or is not statistically significant is unknown.

Assessment Confidence and Data Gaps

Although there are useful data from the Manzanita Lake site and the years it was monitored, data 

are too limited to draw any conclusions parkwide. Due to the large elevation differences within 

the park, and the fact that Manzanita Lake is in a nonrepresentative “rain shadow” location, it is 

unlikely that snow depth at other locations would mirror this site closely.

4.1.4.2 Timing and Rate of Spring Snow Melt and Discharge in Springs and Streams
19

Criteria 

Local and regional data on snow melt timing and stream discharge are insufficient to quantify 

reference conditions appropriate for this park, so qualitative statements will define the reference 

conditions. “Good” condition would be represented by concordance of the current and historical 

seasonal timing (phenology) and rate of spring snow melt, especially at higher elevations which 

control water availability throughout much of the park. “Somewhat Concerning” and

“Significant Concern” ratings would be assigned depending on the degree of discordance 

between the current and historical seasonal timing.

Condition 

Indeterminate. This indicator has not been measured directly in the park. Streamflow timing 

might be inferred partly from by computing late-spring heating days from continuous 

temperature records, or from stream discharges for streams in or near the park. If data are 

sufficient, a fine-scale spatially explicit predictive model of snowmelt might be derived 

empirically by using existing snow depth data from multiple locations and elevations nearest to 

the park, combined with existing data on air temperature, elevation, topographic aspect, and 

other potentially influencing variables. 

Trends

Somewhat Concerning – Low Certainty. Although no data are available that measure this 

indicator directly, trends in some of the following indicators suggest that the timing and rate of 

snowmelt might be shifting. This was not tested. Data through 2011 were analyzed for this report 

and the trends described below were found to be statistically significant. For this trend analysis, 

the Mineral data began in 1927, Manzanita Lake data began in 1949, and Chester data began in 

1957. 

• increase in the minimum high temperature (Min Tmax) – Manzanita Lake

• increase in the minimum observed minimum temperatures (Min Tmin) – Chester and

Manzanita Lake

• decline in % of days with a cold maximum temperature (Tmax< 10th percentile) –

Chester and Manzanita Lake

• decrease in % of days with extreme cold minimum temperature (Tmin < 10th percentile) 

– Chester

• increase in % of days with very warm nighttime temperature (> 90th Percentile Tmin) –

Chester

• fewer entire days with below-freezing conditions (Tmax < 0°C) – Mineral and Manzanita

Lake

• fewer partial days with at least some below-freezing conditions (Tmin < 0°C) – Mineral

and Chester

• fewer cold days (Tmin < -10°C) – Chester

• shorter cold spells – Chester

• longer cold spells – Mineral
20

• decrease in diurnal temperature range (°C) – Chester

• increase in diurnal temperature range (°C) – Manzanita Lake

• more annual precipitation – Mineral

• shorter wet spells – Manzanita Lake

• more annual # of days of precipitation > 20 mm – Mineral

• more days with heavy precipitation (>95th percentile) – Mineral

In addition, Daly et al. (2009) computed trends in temperature and precipitation for each month

at Mineral, Chester, and Manzanita Lake, but for a shorter time period, 1971-2007 (Appendix 

A). They did likewise for the park as a whole using spatially modeled values and also computed 

the 1895-2007 trend at that scale using modeled data. They found that August-September 

precipitation has decreased but that no trend is discernible in annual precipitation. Maximum

temperature in or near the park showed no long term trend, and the 1971 -1990 period was 

somewhat cooler than the rest of the period. 

Assessment Confidence and Data Gaps

Local and regional data on snow amounts and snowmelt timing are insufficient to quantify 

reference conditions, current conditions, or trends for this park. No direct measurements were 

available of the timing and rate of spring melt and discharge in springs and streams within the 

park over extended multiyear periods. A need exists to measure those and then correlate with the 

27 core climate indices. Despite lack of high-elevation measurements and gaps in temporal 

coverage, the existing climate data are believed to be valid. Comparing trends among the three 

Lassen weather data sites is not valid because of their different periods of record, high variability 

within sites, and different incidences of missing records. 

4.1.4.3 Perennial Stream Extent, Seasonal Flow Volume, Wetted Width

Criteria 

Local and regional data on perennial stream extent, seasonal flow volume, and wetted width are 

insufficient to quantify reference conditions appropriate for this park, so qualitative statements 

will define the reference conditions. “Good” condition would be represented by concordance of 

the current and historical snowpack amounts, such that no section of a perennial stream within 

the park becomes ephemeral more often than it has historically, or experiences measurable 

reduction in its width or seasonal flow volume. Somewhat Concerning” would be some reduction 

in flow and extent of perennial length, affecting some of the park’s key ecological processes and 

natural resources. “Significant Concern” would be reductions that are widespread, resulting in 

non-support of those processes. 

Condition 

Indeterminate. Very limited data are available from the USGS for stations near the park with the

following codes: 11376038, 11376100, 11376200, 11381000, 11355500. There are a sufficient 

number of years to compute trends only at the last one (Hat Creek), which is located about nine

miles north of the park, and only for the period 1927 through 1994.
21

Trends

Indeterminate. USGS daily flow data were obtained for Hat Creek. Dates were converted to the 

Julian calendar (January 1 = 1, December 31 = 365, etc.). Peak flow during most years occurred 

in the May-June period, primarily reflecting snowmelt from higher elevations. For each year, the 

dates during the spring (defined as April-July) when the five highest flows occurred were 

averaged. These averages were then plotted against year. No evidence was found that the date of 

peak runoff is occurring earlier in the spring, or that the size of peak flow is becoming larger or 

smaller. For this particular station during this time period, the median date of peak springtime 

flow was May 29 (earliest was April 15, latest was June 25). The median peak springtime flow 

was 205 cfs (115-372 cfs). The larger peak flows tended to occur during years when the peak 

occurred later in the spring.

Figure 4. Average daily flow 1927 to 1994 at Hat Creek. Hat Creek originates within the park but these 

measurements are from a stream gauge located outside the park. The curved line is the locally weighted 

regression line (with 40% smoothing). The straight line is the least squares regression with confidence 

bands. R2=0.1316, p=0.0025, slope= 0.5310, n= 67.

80

90

100

110

120

130

140

150

160

170

180

190

200

1920 1930 1940 1950 1960 1970 1980 1990 2000

Daily Stream Flow (cfs)
22

Figure 5. Dates of springtime peak flow, 1927 to 1994 at Hat Creek. Hat Creek originates within the park 

but these measurements are from a stream gauge located outside the park. The curved line is the locally 

weighted regression line (with 40% smoothing). The straight line is the least squares regression with 

confidence bands. 

Assessment Confidence and Data Gaps

The analysis of the data from the single gauging station near the park is insufficient because of 

the distance between the park’s snowpack and the gauging station, as well as the confounding 

influences of antecedent soil saturation (as separate from melting snowpack), late spring rainfall, 

and other factors which could not be determined. For the other indicators (e.g., location of 

perennial stream headwaters, a downslope movement of which could signal a shift to a drier 

climate), no data were available so condition or trends cannot be described. 

Ideally, criteria would also specify what volume of snowpack is needed to sustain stream flow

and water table levels for specified durations and channel widths under a variety of temperature

conditions during the subsequent growing season. This cannot be determined without computer 

simulations calibrated with field measurements from specific locations in the park. Lacking such

data, the assessment of the adequacy of current and future snow pack could be based on

comparison with average historical discharges of snowpack-fed streams at the highest elevations

where discharge was continuously measured. Additionally, the upper portions of the park’s

perennial streams could be walked at the driest time of an average year and their headwater

(highest point of perennial flow) location pinpointed with GPS. Of predictive importance are the 

frequency of no-flow or low-flow conditions, the annual daily mean flow, the total annual flow, 

and the date of peak discharge attributable at least partly to snowmelt (i.e., late spring and 

summer). Without installation of continuous-flow monitoring gauges and plotting of 

hydrographs from the collected data, these cannot be determined.

120

125

130

135

140

145

150

155

160

165

170

175

180

1920 1930 1940 1950 1960 1970 1980 1990 2000

Julian Date of Springtime Peak Flow
23

4.1.4.4 Number, Area, and Distribution Pattern of Wetlands, Ponds, and Lakes

Criteria 

“Good” condition would be represented by concordance between the current and historical 

number, area, distribution, and ecological condition of wetlands, ponds, and lakes as determined

partly by using the variables recorded by Adamus & Bartlett (2008). “Somewhat Concerning” 

would be a slight but persistent reduction in the ecological condition of wetlands, ponds, and 

lakes, but without a large reduction in their number, area, or distribution. “Significant Concern” 

would be a major reduction in all of these metrics. It is recognized that wetlands are naturally 

dynamic and some wetlands fluctuate between years from being seasonally to persistently 

flooded, and those cycles are beneficial to their productivity. 

Condition 

Good. The park’s wetlands were first mapped by the National Wetlands Inventory (NWI) in the 

1980s using color infrared imagery with a scale of 1:58,000. Refinements and additions were 

made in 2005 by Adamus & Bartlett (2008). Permanent markers were placed in each of 68 

wetlands comprising a probability sample of an estimated 990 wetlands in the park. The sample 

wetlands were visited once and were mapped using GPS, with the coordinates reported in a 

database provided to the Klamath Network. These assessments determined that nearly all 

wetlands are in good condition as defined mainly by their plant communities. A wetland 

assessment method (CRAM, California Rapid Assessment Method; Collins et al. 2006) was 

applied to the data from all the 68 surveyed wetlands, resulting in a median CRAM score of 78 

on a scale of 10 to 100 (as compared with a median of 46 for riverine wetlands outside the park

assessed by other people)10. This suggests that the park’s wetlands might be in relatively good

condition. However, CRAM does not use any direct measures of wetland health, such as

amphibian productivity. Moreover, CRAM scores from the park’s wetlands were not correlated

significantly with any of the independent measures of potential risks to those wetlands (e.g.,

proximity to roads and trails, visual evidence of human visitation), as would be expected.

Trends

Indeterminate. No data are available for estimating trends in their quantity or quality (ecological

condition). The wetlands spatial data from the Adamus & Bartlett assessment provide a

reasonably complete baseline for wetland area and distribution in the park, and the data provide a

partial baseline for comparing future wetland quality.

Assessment Confidence and Data Gaps

Medium. The park’s wetlands were initially mapped by the National Wetlands Inventory using 

aerial photographs from the 1980s. The Adamus & Bartlett (2008) survey ground-truthed many 

of those mapped wetlands and added others, but did not involve walking all likely parts of the 

park to intentionally search for unmapped wetlands. Also, the Adamus & Bartlett survey did not

measure contaminants, other water quality variables, groundwater levels, amphibians,

underwater aquatic plants, or several other indicators of wetland ecological condition.

 

10 Calculated from data posted on the CRAM web site (http://www.cramwetlands.org/) as of 18 March 

2007.
24

4.2 Changes in Surface Waters and Their Resources

4.2.1 Background

Surface waters include streams, ponds, lakes, geothermal springs, and wetlands. The quantity,

quality, and distribution of these influence and are influenced by local climate, soils, vegetation,

wildlife, and fish and other aquatic animals. They also are a major source of park visitor

enjoyment. Watershed boundaries are shown in Figure 3. These were modeled from topographic 

data, with each watershed beginning at the park boundary and extending upslope into the park.

4.2.2 Regional Context

Geothermal springs are a major feature drawing people to the park, along with more than 200 

ponds and lakes. Over the past 300,000 years, volcanism has greatly altered the park’s landscape

and created a wide array of thermal features such as roaring fumaroles, mudpots, boiling pools, 

and steaming ground. The park has several high-elevation, acid-sulfate, low-chloride springs that 

are characteristic of vapor-dominated hydrothermal systems (Ingebritsen and Sorey 1985). These 

geothermal acidic features represent some of the most extreme life-supporting environments on 

earth. Temperatures range from 50 to 115◦

C, and pH from 0 to 3. Boiling Springs Lake is the 

third-largest body of geothermally-warmed water anywhere in the world. Data from various 

sampling sites within the park indicate that geochemical composition of springs varies widely 

even among features in similar areas of the park with similar temperatures and pH values 

(Thompson 1985). The park’s geothermal features provide an unusual chemical environment due 

to their mineral-rich underground source and the rapid evaporation associated with hot surface 

temperatures. In many of the springs in the Growler and Morgan Hot Springs area, chloride and 

arsenic occur at levels that would threaten most of the usual forms of aquatic life. However, in 

this park, as in the hot springs of Yellowstone National Park, there are unusual microbes 

(Archaea) which not only tolerate severe conditions, but can actually derive energy by 

processing sulfur compounds or methane, while not depending on sunlight or organic matter for 

food. Most geothermal features are located in the southwestern part of the park and nearly all 

(except for the springs at Drakesbad Meadow) are acidic and rich in hydrogen sulfide and sulfate 

(Thompson 1983). At a scale of a few meters, the locations of hydrothermal features such as 

mudpots can shift with time as the underground plumbing changes and pathways of fluid flow 

are sealed by mineral deposition or fractured by seismic activity. Thermal water discharging at

Morgan Hot Springs and Growler Hot Spring as well as the deep thermal water at Terminal 

Geyser probably originates beneath the surface at Bumpass Hell (Thompson 1983).

Compared with many other areas in California, the park’s water bodies are at relatively low risk 

from pollutants carried in via water from locations outside the park, because the park is at the top 

of several watersheds and no surface water enters from outside the park. Nonetheless, highelevation aquatic ecosystems in the Sierra Nevada are particularly sensitive to additions of 

atmospheric nitrogen and sulfur because the waters are generally nutrient-poor and have a low 

capacity to buffer these additions without becoming acidified or experiencing major biological 

changes (Sullivan et al. 2001, Mutch et al. 2008). The capacity of the park’s waters to buffer the

acidifying effect of these particles is limited by very low concentrations of calcium and other

base cations. The low buffering capacity is due to soils in many areas of the park being very

young, thin, and poorly developed, partly as a result of the volcanic eruptions and erosion events 

in 1915, and partly due to the magnesium-rich granitic composition of most of the area’s bedrock 

(Clow et al. 2003). Of the seven lakes sampled by EPA’s Western Lake Survey in the park in the 
25

1980s, five had levels of acid neutralizing capacity low enough to indicate that they are at risk of 

both episodic and chronic acidification (Eilers et al. 1987). Small water bodies (i.e., ponds and 

wetlands) are most at risk when they lack surface water outlets and are fed by relatively small

high-elevation contributing areas. Phytoplankton, and epiphytic and benthic algae in these waters

are likely to be most sensitive to acidification and nitrogen deposition, with unknown

consequences for other components of the aquatic food web.

4.2.3 Issues Description

Several factors can potentially degrade the quality of the park’s water bodies and in some cases

threaten their very existence. The more notable of these include the following, which are

subsequently described:

• Climate Change

• Deposition of Atmospheric Nitrogen and Sulfur 

• Deposition of Other Airborne Contaminants

• Changes Resulting From Fires and Fire Control Activities

• Visitor-associated Water Contamination

• Ecologically Harmful Aquatic Plants and Animals

• Natural Sources

4.2.3.1 Impacts from Climate Change

Historical climate conditions and predicted future changes are described generally in section 4.1.

Changes in the extent and duration of snowpack, ice cover, stream flow, lake and wetland water

levels, temperature, and chemistry will likely occur as a result of predicted climate change, and 

will affect biological resources. In general, the most sensitive species tend to be boreal species

near the southern edge of their range which occur at higher elevations and have limited mobility 

and low reproductive rates. Several of the park’s aquatic plants and animals fit one or more parts 

of this description. An analysis of the vulnerabilities of California nesting birds to climate 

change was published by Gardali et al. (2012). Of 128 species they identified as most vulnerable, 

those which are aquatic or wetland-associated and are likely to have formerly or currently nested

in the park include Barrow’s goldeneye, bufflehead, eared grebe, osprey, willow flycatcher, and 

Lincoln’s sparrow.

4.2.3.2 Impacts from Air Pollution: Deposition of Atmospheric Nitrogen and Sulfur

At least one recent study attributed enrichment of high-elevation lakes in the Sierra Nevada to

deposition of atmospheric nitrogen (Sickman et al. 2003). This is potentially a significant 

concern in Lassen because the park’s waters are nutrient-poor, due partly to their headwater 

positions. Some of their aquatic flora and fauna are thus not equipped to survive significant 

increases in nutrients. Moreover, even slight changes in species composition of aquatic algae in 

response to increased nutrients can alter aquatic food chains, sometimes with results that appear 

to be detrimental.

4.2.3.3 Impacts from Air Pollution: Deposition of Other Contaminants

Although few pollution sources remain within the park, long-distance airborne transport of 

pesticides and other contaminants poses a potential threat. In other parts of the Sierras, long 

distance transport of airborne pesticides has been noted (Zabik and Seiber 1993, McConnell et al. 
26

1998) with possible damage to aquatic invertebrates and amphibian populations (Davidson 

2004).

4.2.3.4 Aquatic Impacts of Fires, Fire Control Activities, and Vegetation Change

The type, amount, and spatial pattern of vegetation strongly influences aquatic systems (Ball et 

al. 2010) and is in turn affected by fire. Thus, the magnitude and frequency of some types of 

disturbances in aquatic systems, such as changes in shading and sediment loads from erosion,

depend on the severity and frequency of fire. Fire also can have long-term effects on aquatic

systems by changing the dominant land cover along streams and other water bodies. For

example, the amount of plant litter, its decay characteristics, and its potential for delivery to and

through aquatic systems can profoundly influence aquatic invertebrate and fish communities.

The fire regime at Lassen is described in section 4.3.

4.2.3.5 Visitor-associated Water Contamination

Soil erosion has been accelerated locally within a few heavily traveled areas of the park, due to

compaction, vegetation damage, and changed runoff patterns. High levels of overnight use have

been reported to have caused substantial damage adjacent to some lakes (NPS 1999). Damage

included loss of vegetation, soil compaction, increased sediment loads in water bodies, and, less 

frequently, bacterial pollution of surface water.

4.2.3.6 Impacts from Ecologically Harmful Aquatic Plants and Animals

In other parts of California, several exotic plants and a few non-native animals have extensively 

invaded wetlands and some other water bodies (California Dept. of Fish & Game 2008). When 

this happens on a large scale, some native species are extirpated and ecosystem processes can be

altered in unpredictable ways. Invasions are more likely to occur at lower-elevation aquatic sites 

that receive heavy recreational use, as well as those experiencing unnatural water level 

fluctuations as a result of human activities. 

4.2.3.7 Natural Sources

The volcanic eruptions of 1915 resulted in massive deposition of sediment and nutrients in some

of the park’s water bodies. Also, at a few locations the chemical concentrations in geothermal

springs naturally exceed levels considered harmful to some freshwater species at other locations.

Elevated arsenic levels in Mill Creek and Canyon Creek, which are fed by geothermal springs, 

persist more than 2 km downstream (Sorey 1986). 

While fires themselves are major agents of change, fire-fighting, especially in steep terrain,

potentially results in additional disturbance that affects aquatic systems including soil

compaction and contamination from fire retardants. Applications of fire retarding chemicals have

not been documented at Lassen, but in recent years NPS policy is to avoid the use of fire

retardant as much as possible. Fire retardant agents must be on an approved list for use by the

Forest Service and Bureau of Land Management, and must not be applied within 200 feet

upslope of any wetland, stream, or other water body. Fire retardants used in controlling or

extinguishing fires contain about 85% water, 10% fertilizer, and 5% other ingredients such as

corrosion inhibitors and bactericides. Fire suppressant foams are more than 99% water. The

remaining 1% contains surfactants, foaming agents, corrosion inhibitors, and dispersants.
27

4.2.4 Indicators, Criteria, Condition, and Trends

Indicators that might be used to monitor degradation of surface waters and their resources

include the following, with the goal of maintaining conditions within the expected natural range

of interannual variation:

1. Proportion of water bodies regularly experiencing exceedances of key thresholds for

important water quality parameters; i.e., those that are important to human health,

maintenance of aquatic ecosystem processes, and the continued survival of important

species and biological communities;

2. Presence and persistence of the current diversity of native aquatic plant and animal

species;

3. Proportion of the park’s wetlands, ponds, lakes, and riparian segments in which

invasive species have (a) colonized or (b) become dominant, and have reduced native

species richness.

To develop meaningful criteria for evaluating these, it is important to understand each indicator’s

natural range of variation and/or its potential for harming the park’s resources. Invertebrate and 

fish data collected from the park’s lakes in 2008 and 2010, and from the park’s streams in 2011, 

will help define the expected spatial variation. However, those data were not available for review 

at the time of report preparation. Therefore, criteria are based on published standards related to

ecological harm, or on professional judgment of the authors. The indicators are described in the

following sections.

4.2.4.1 Water Quality Threshold Exceedances

Criteria 

Local and regional data on water quality are insufficient to quantify reference conditions that are 

appropriate for those waters of this park that are chemically atypical due to natural geothermal 

phenomena. However, those waters are relatively limited in extent within the park. To define 

reference conditions, criteria and standards for protection of aquatic life, as published by federal 

and state agencies, were consulted. “Good” condition would be represented by no exceedances

or increases in substances harmful to aquatic life during a multiyear period of assessment, except 

as attributable solely to natural factors, e.g., catastrophic floods, geothermal effluent. This is

consistent with the antidegradation policies of state and federal regulatory agencies. “Somewhat 

Concerning” condition would be a slight and/or occasional exceedance of a water quality 

standard. “Significant Concern” would be severe, chronic, or acute exceedances of a water 

quality standard at concentrations that could harm aquatic life. 

Condition

Good. Water quality data prior to 1999 were compiled and summarized in a “Horizon Report” by 

NPS (1999), and briefly by Hoffman et al. (2005). Results from some of the more recent 

sampling are reported by Currens et al. 2006 and Janik & Bergfeld 2010. The Horizon Report 

covering this park noted at least one exceedence of EPA aquatic life protection criteria for the 

following: dissolved oxygen, pH, chloride, chlorine, and arsenic. Sulfate, chloride, arsenic, and 

barium exceeded their respective EPA criteria for drinking water standards. Fecal-indicator 
28

bacteria concentrations (fecal coliform) and turbidity occasionally exceeded screening limits for 

freshwater bathing and aquatic life, respectively. Dissolved oxygen problems were present at 

least once in Reflection Lake, Horseshoe Lake, Butte Lake, and Boiling Springs Lake. The low 

levels of dissolved oxygen in these lakes is likely to be a natural occurrence. Low pH (harmful 

acidity) was noted from far more samples than excessively high pH (harmful alkalinity). The 

highest pH (9.7 SU) was reported from an unnamed spring in the area of Growler and Morgan 

Hot Springs and the lowest pH (1.7 SU) from an unnamed spring in the northern section of 

Bumpass Hell. 

As a supplement to the NPS Horizon Report and this report, in December 2011 we queried the 

USEPA STORET database. This yielded 9342 records of measurements of 61 water quality 

parameters from 246 sample points among the park’s waters between June 1960 and September 

2005 (the most recent data available online). Table 3 summarizes some comparisons with official 

water quality criteria. 

Trend

Indeterminate. Sampling has mostly been sporadic over the past 50 years, and has been 

conducted with insufficient regularity and quality control to determine trends. None of the water

quality characteristics in the STORET database have been monitored at the same location with

sufficient frequency (seasonal and annual) to reliably examine multiyear trends. Monitoring of

trends in pH, turbidity, and temperature in the park’s waters (especially the smaller ponds and

seasonal wetlands) is of particular interest, as these broadly influence the cycling and

bioavailability of many other substances as well as habitat suitability for amphibians and

crustaceans. They are most likely to be affected by climate change and the types of disturbances

that are most common within the park.

Table 3. Comparison of water samples from Lassen with USEPA thresholds for potential harm to aquatic 

life. An unknown portion (but likely a majority) of these samples were from hydrothermal features, which 

commonly exceed criteria due to natural geochemistry. “Sites” are loosely defined; some may be within a 

few feet and in the same water body while others are miles apart. Data source is EPA’s STORET 

database. Threshold for aluminum= 87 μg/L; arsenic= 150 μg/L; barium= 1000 μg/L; chloride= 230 mg/L; 

iron= 1000 μg/L; manganese= 50 μg/L; pH= 9.0. For pH, there were also 58 sites that were too acidic (pH 

< 6.5). 

Parameter Units Maximum

# of Sites 

Sampled

# of Sites 

Exceeding the 

Criteria

Aluminum, dissolved μg/L 28000 18 12

Arsenic, dissolved μg/L 24300 6 5

Barium, dissolved μg/L 3100 13 9

Chloride mg/L 2370 72 20

Iron, dissolved μg/L 63000 39 29

pH SU 9.95 189 11
29

Assessment Confidence and Data Gaps

Low. Confidence in the existing data from the park is limited by the non-systematic temporal and

spatial coverage of past water sampling efforts. However, data from a new, relatively 

comprehensive sampling program that measures water quality in a statistical sample of the park’s 

lakes and streams should be available soon. As noted above, trends could not be assessed.

Confidence in the applicability of the USEPA water quality criteria to conditions in most of this

park is moderate to high, being limited only because it is unknown whether the tolerances of the

fauna in the park’s water bodies are similar enough to those of the species used by USEPA in its

toxicity testing.

4.2.4.2 Diversity of Native Aquatic Species and Habitats

The park’s six largest lakes—Juniper, Snag, Butte, Horseshoe, Lower Twin, and Upper Twin—

are all in wilderness areas that have been either designated or proposed. Manzanita, Butte, and 

Blue Lake Canyon Lakes are the only natural lakes likely to have been inhabited by fish 

historically (Parker et al. 2008).

Floristic Quality Assessment (FQA) indices have been developed in other regions of the United

States for quantifying the intactness of plant communities (including those of wetlands and 

lakes), but no such plant indices have been developed for this part of California. Similarly, 

Indices of Biotic Integrity (IBIs) are often used to evaluate the condition of aquatic invertebrate

or fish communities. Although none have been developed or calibrated to the specific conditions

present in this park or nearby areas, the general principles they embody are being applied by 

NPS to interpret data collected from the park’s streams in 2011.

In national forests of the Sierra Nevada region, the USDA Forest Service (2008) has chosen and 

is monitoring the following aquatic or wetland-associated species or groups and their associated 

habitats as “management indicator species”:

Pacific tree frog – wet meadow

yellow warbler – riparian woody vegetation

aquatic macroinvertebrates – riverine and lacustrine

Criteria 

Condition of the park’s aquatic biota could be evaluated relative to a goal of sustaining the

natural turnover rates of all native aquatic species currently inhabiting the park. By “natural 

turnover rates,” we mean the changes in abundance or presence attributable to expected natural 

factors, either gradual (e.g., vegetative succession) or event-focused (severe storms, fire). A more

detailed goal might be to sustain the proportions and functional characteristics of species that 

reflect well-functioning food webs and ecological intactness. However, there are no legallysanctioned numeric criteria for evaluating the degree of intactness of any of the park’s aquatic 

plant or animal communities. Likewise, local and regional data on natural turnover rates, 

minimum viable population levels, desired productivity or species richness levels, or other 

attributes of native aquatic species and their habitats are insufficient to quantify reference 

conditions appropriate for this park. Thus, qualitative statements will define the reference

conditions. “Good” condition would be represented by concordance between the current and 
30

historical turnover rates of all native aquatic species inhabiting the park. “Somewhat 

Concerning” condition would be loss of one or a few native aquatic species historically present. 

“Significant Concern” condition would be loss of several native aquatic species historically 

present, in excess of natural turnover rates.

Condition

Somewhat Concerning – Low Certainty. A rating of “Good” is not assigned because of the 

apparent disappearance from the park of Cascades frog. Also, at least four native bird species

which are known to have nested in the park historically, though with unknown regularity, have

not been documented nesting for at least a decade. They are common loon (last nested in 1948),

canvasback (last nested in 1951), redhead (last nested in 1976), and Barrow’s goldeneye (last 

nested in 1920s). Whether the extirpation of these species is simply part of natural turnover rates, 

or is due to fine-scale human influences (such as the introduction of fish to some lakes and/or 

disappearance of those fish in subsequent years) or broad-scale factors (such as climate change 

that may have affected these essentially boreal species in unknown ways), remains uncertain.

A pond survey 35 years ago (West 1976) covered 162 wetlands, ponds, and lakes in LAVO. In 

131 systems the following were measured (Hoffman et al. 2005): 1) water temperature, 2) color, 

3) clarity, 4) site depth (maximum and mean), 5) site bottom and shore type, 6) watershed 

condition, 7) site surface area, 8) presence and location of inlets and outlets, 9) fish presence, 10) 

presence of fish predators, and 11) relative abundance of aquatic invertebrates and vegetation. In 

the mid-1980s the USEPA’s Western Lake Survey analyzed physical and chemical 

characteristics of seven Lassen lakes (Landers et al. 1987, Eilers et al. 1987). However, until 

recently only wetland plants (Adamus & Bartlett 2008) and lentic fish and amphibians (Stead et 

al. 2005) had been the subject of publications based on park-wide biological surveys. As noted 

earlier, the Klamath Network implemented an extensive survey of the park’s lakes and streams in 

2008-2011, but data were not available for review in time for preparation of this report. 

The Adamus & Bartlett wetland study in 2008 did not survey plants that live completely

underwater; the survey detected 51% of the park’s known wetland flora. Among the 338 plant

taxa (both wetland and upland), at least two were found that are listed by the California Native

Plant Society as rare or having limited distribution. In most wetlands, more than 30 plant species

were found, and most of the 100 m

2 herbaceous plots in wetlands had more than 13, with a

maximum of 43. The plant species composition tended to be more unique in wetlands that were

dominated by emergent (herbaceous) vegetation, not on lakeshores, at lower elevations, and 

intercepted by streams. At least two acid geothermal fens, a relatively rare and sensitive wetland 

type in California (Cooper & Wolfe 2006, Weixelman et al. 2006), were identified. These are fed 

largely by warmed groundwater and have extensive moss cover. They are present near Forest 

Lake area, just east of Ridge Lakes, and next to Bumpass Hell. Just outside the park, the 

sphagnum moss wetland along the edge of Willow Lake is unusual for the region. Little Willow 

Lake just inside the park also has a floating Sphagnum mat and supports a similar assemblage of 

plants unusual for this region.

A separate survey of 365 of the park’s wetlands and ponds in 2004 (Stead et al. 2005) found 

amphibians in 90% of the surveyed lakes, 73% of the wet meadows, 64% of the permanent 

ponds, and 47% of the temporary ponds. The most widespread species was Pacific treefrog 

(Pseudacris regilla) at 59% of the sites, followed by long-toed salamander (Ambystoma 
31

macrodactylum) at 10% of the sites, western toad (Anaxyrus boreas) at 8%, and Cascades frog

(Rana cascadae) and rough-skinned newt (Taricha granulosa) at just 1% each. The Cascades

frog is listed as a federal and state species of concern and was considered abundant throughout

the park until the mid-1970s. It is estimated that the frog has now been extirpated from about 99

percent of its southernmost range (Lassen Peak and surroundings) and 50 percent of its total

historical distribution in California. In 1974, Pacific treefrogs with extra hind legs were first

discovered in the park, and a resurvey between 1999 and 2002 found hind limb deformities to be

common in this species. The cause is believed to be an infection from a parasite (Ribeiroia

ondatrae) that is hosted by aquatic flatworms (Johnson et al. 2003).

Among reptiles, western terrestrial garter snake (Thamnophis elegans) and the common garter 

snake (T. sirtalis) were found most often by the Stead et al. survey (2005). Either or both were 

found at 26% of the mainly aquatic sites. Although not listed as threatened or endangered 

statewide, the western pond turtle (Actinemys marmorata) is believed to be suffering from 

declines in large parts of its range. Although previously documented in the Manzanita and 

Reflection Lake area, there have been no recent sightings in the park. 

Aquatic invertebrates were surveyed in most of the park’s lakes and ponds by Parker et al. 

(2008). The Klamath Network also completed an invertebrate survey of the park’s lakes and 

streams (Dinger et al. 2012) but data were not available for review during preparation of this 

report. Underwater visual surveys of aquatic vegetation have been done in a few places by Dr. 

John DeMartini of Humboldt State University, but similarly, the data have not been published 

and were not available for this report.

Native fish known from the park include speckled dace (Rhinichthys osculus), Lahontan redside

(Richardsonius egregius), tui chub (Siphateles bicolor), rainbow trout (Oncorhynchus mykiss),

and mottled sculpin (Cottus gulosus) (Potts and Schultz 1953). Records from the park of the 

Modoc sucker (Catostomus microps), which is listed as endangered by both the state and federal

governments, have been determined to be a misidentification. Some of the park’s ponds have

reverted to their historically fishless condition as a result of winterkill (naturally low levels of

dissolved oxygen under prolonged ice conditions). The associated loss of mostly non-native 

predatory fish has been shown to be beneficial to some of the park’s amphibian species (Stead et 

al. 2005) and to overall diversity of the park’s aquatic invertebrates (Parker et al. 2008). 

Physical habitat characteristics in the park’s streams have not been widely quantified, and

headwater origin points of perennial flow in the park’s streams have not been precisely located.

One of the park’s streams, Mill Creek, is exceptional among regional streams in having no dams

blocking anadromous fish, and appears to be relatively undegraded most of the distance from its

origin in the park downstream to the Sacramento River. Mill Creek is listed in the Lassen

National Forest’s Land Management Plan as a candidate for inclusion in the National Wild and

Scenic River System. Kings Creek supported what was apparently the world’s only population of

the Kings Creek caddisfly (Parapsyche extensa), discovered in 1948 but believed to be no longer

present.

Several studies have examined microbial diversity in the park’s hot springs (Whitaker et al. 

2003, Brown & Wolfe 2006, Siering et al. 2006, Tin et al. 2011) and fumarole steam vents 

(Benson et al. 2011). These have provided evidence that geothermal features can be connected 
32

via the subsurface over long distances and that subsurface sources provide a potentially diverse 

source of microorganisms for downstream waters (Tin et al. 2011).

Bufflehead (a duck) has been a particular focus because the park is at the southern edge of its

range, perhaps making it highly susceptible to the effects of global warming. Data collected by

park biologists annually since 1997 describe number of adults (and with or without broods),

number of broods, number of young, size and age of young at various times post-hatch,

associated fish species, and survey effort. Maps have also been created and color-coded to

represent areas surveyed and not surveyed. The surveyed areas are further divided into areas of

buffleheads with broods, areas of adult buffleheads, areas of no buffleheads, and areas not

officially surveyed but where buffleheads were noticed. Other waterbirds are noted, but mallard, 

Canada goose, and common merganser are the only others that are equally or more common, and 

no large wading birds nest in the park. A bird closely associated with streams—the American 

dipper—is a fairly common breeder. 

Trends 

Indeterminate. It is certain that numbers of at least one of the park’s species (Cascades frog) 

have declined to the point of extirpation, and as described above under Condition, four 

waterbirds that historically bred in the park no longer do. On the other hand, it is also certain that 

non-native fish introduced into many of the park’s lakes up until perhaps the 1990s have now 

disappeared due to natural factors (Parker et al. 2008), and this trend can be viewed as positive 

relative to a goal of maintaining the park’s diversity of aquatic invertebrates and amphibians. An 

overall rating of “Indeterminate” is assigned because of the presence of both positive and 

negative trends (depending on aquatic group), and because quantitaive data are not sufficient to

quantify trends in most of the park’s aquatic plant, invertebrate, and amphibian species.

Assessment Confidence and Data Gaps

Low. Confidence in trends is limited by lack of published surveys of underwater plants and 

historical surveys of other forms of aquatic life.

4.2.4.3 Water Bodies with Ecologically Harmful Species

Criteria 

Local and regional data on invasive aquatic animals and plants are insufficient to quantify

reference conditions applicable to this park, so qualitative statements will define the reference

conditions. “Good” condition would be represented by complete absence of non-native aquatic 

plant or aquatic animal species that threaten the long-term persistence of native species currently

existing within the park. “Somewhat Concerning” and “Significant Concern” ratings would

reflect increasing degree and extent to which native species are being impacted by invasive 

aquatic species.

Condition 

Somewhat Concerning – Low Certainty. The park hosts four non-native fish species—golden

shiner (Notemigonus crysoleucas), fathead minnow (Pimephales promelas), eastern brook trout

(Salvelinus fontinalis), and brown trout (Salmo trutta). Their adverse effects on native aquatic 

life in the park’s lakes, ponds, and wetlands have been demonstrated (Parker et al. 2008). Trout 

have been introduced in all of the park’s streams, but effects on aquatic communities in the 
33

park’s streams are unmeasured. For recreational purposes, non-native sport fish were introduced

into at least 42 of the park’s lakes and ponds until perhaps the early 1990s, sometimes 

repeatedly. Currently, only about 14% of surveyed lakes in the park have fish (Parker et al. 

2008).

Long-toed salamander, Cascades frog, and Pacific treefrog are commonly consumed by trout.

Among 728 ponds in the Klamath Mountains surveyed in 1999-2002 by Welsh et al. (2006), 

fishless ponds were far more likely to support these amphibian species which are normally prey 

for fish. Similar results were found at Lassen by Stead et al. (2005) who also found that fishless 

ponds were more likely to host a native fairy shrimp (Streptocephalus sealii) that fish consume, 

which was present in 15% of the 365 wetlands and ponds that were surveyed. 

A survey of 365 of the park’s wetlands and ponds in 2004 (Stead et al. 2005) did not report any 

occurrences of bullfrog (Rana catesbiana). A variety of pathogens, such as chytrid fungus and

ranavirus, have been found elsewhere to seriously impact amphibian populations and have been 

found in the park. 

A number of plant species found partly in wetlands and along streams are considered to be

“disturbance species.” Nearly all are non-natives, and some are invasive weeds. Studies 

elsewhere have shown they increase around areas of human or natural disturbance. A botanical 

survey of 68 of the park’s wetlands in 2005 (Adamus & Bartlett 2008) found 19 disturbance 

species (6% of all species encountered) among 44 of the 68 wetlands that were surveyed. In the 

100 m2 herbaceous plots, the median number of disturbance species was zero. In the 400 m

2

shrub plots, the median number of disturbance species was seven. For entire wetlands, the

median number of disturbance species among all wetlands was two. The number of disturbance

species was greatest in large, sloping, relatively wet shrub and forested wetlands intersected by

streams with higher conductivity and in the western part of the park. The number of disturbance

species, as well as the percent of a wetland’s species list that was comprised of disturbance

species, increased the closer a wetland was to a road. However, the percentage decreased with

proximity to trails. The total number of plant species also increased significantly closer to roads.

To date, there are no park records of the New Zealand mud snail (Potamopyrgus antipodarum)

or other ecologically harmful invertebrates known to occur in northern California (personal 

communication, Eric Dinger, NPS Klamath Network, Ashland, Oregon).

Trends

Indeterminate. Surveys indicate a decline in the number of lakes and ponds inhabited by nonnative fish. Nonetheless a rating of “Indeterminate” is assigned because data are not sufficient to

determine if there are long term trends across the park in harmful aquatic plants.

Assessment Confidence and Data Gaps

Medium. Although significant occurrences of invasive plants have mostly been surveyed in a 

sample of wetlands, not all wetlands were surveyed. Also, there are no published surveys that 

describe locations of invasive underwater plants and invertebrates in the park’s streams and 

lakes.
34

4.3 Changes in Terrestrial Vegetation

4.3.1 Background

Vegetation is a foundation for terrestrial ecosystem composition, structure, and function.

Vegetation ranked as a key vital sign for monitoring of ecological integrity in the Klamath

Network Inventory and Monitoring Program. Vegetation composition includes an array of

ecosystem components such as species, populations, genetic composition, and special habitats.

Vegetation structure refers to the vertical and horizontal arrangement of components, such as

canopy structure and corridors for species movement. Vegetation function refers to ecosystem

processes such as cycling of nutrients, carbon, and water—which interact with disturbance

processes and biological components such as interspecific competition, and demographic and

reproductive processes. Vegetation dominates biomass and energy pathways and defines the

habitat for most other forms of life. Indicators for vegetation composition, structure, and function

are therefore essential for defining the ecological integrity of park terrestrial ecosystems.

Vegetation structure, function, and composition can be altered by many park activities (e.g., fire

management) or from extrinsic factors (e.g., off-site pollution, climate change, invasive species) 

(Figure 6). These affect the structure of the habitat, particularly the disturbance regimes, as well

as the landscape patterns that create habitat for a wide variety of species.
35

Figure 6. Human influences on the structure, function, and composition of ecosystems.

Along a hypothetical elevation gradient from low to high, Lassen’s vegetation is dominated by 

white fir and mixed conifer forests, Jeffrey pine (Pinus jeffreyi) forests, lodgepole pine (P.

murraya var. contorta) forests, red fir (Abies magnifica) forests (the most abundant type), and 

modest amounts of subalpine forests and woodlands of mainly mountain hemlock (Tsuga 

mertensiana), with inclusions of whitebark pine (P. albicaulis) (Parker 1991). The highest 

elevations, particularly Lassen Peak itself, are characterized by mostly rock and persistent snow 

with a very sparse cover of herbaceous vegetation. Within the lower elevation conifer belt, there 

are localized areas of montane chaparral shrub vegetation due to fire and soil conditions. There 

are also large expanses of barren lava fields or pyroclastic deposits with very sparse herbaceous 

vegetation or no vegetation. Wet meadows and perennial grasslands occupy a small area, as do 

specialized vegetation such as riparian forests and aspen stands. Table 4 lists the broad 

vegetation types and the area they occupy currently.

Far-field 

Influences

Near-field 

Influences

ECOLOGICAL INTEGRITY OF ECOSYSTEMS

Local Disturbance

Point Source 

Pollution

Visitor Use Function

Disturbance 

Regimes

Water, 

Energy, & 

Nutrient 

Cycling

Biological 

Interactions,

Demography,

Reproduction

Structure

Abiotic

Gradients

Biotic 

Gradients

Spatial

Pattern

Fire Suppression

Global Warming

Invasive Species

Diffuse Pollution

Urban Encroachment

Composition

Focal 

Communities 

Rare & 

Sensitive

Species 

Keystone 

Species

& Ecosystems
36

Table 4. Area of broad vegetation types in Lassen. The areas are based on the 2007 vegetation map 

prepared by James von Loh, but uses the classification of Wildlife Habitats (WHR) from the California 

Vegetation Map (Cal-Veg) prepared by the US Forest Service 

http://www.fs.fed.us/r5/rsl/projects/frdb/layers/ev_mid.html. 

Vegetation Area (ha)

Red fir forest 21,540

Lodgepole pine forest 5,569

White fir forest 4,750

Barren* 4,195

Jeffrey pine forest and woodland 2,625

Montane chaparral 2,125

Subalpine conifer woodland and forest 1,611

Alpine dwarf shrubland 381

Wetland 360

Montane riparian 181

Perennial grassland 145

Sagebrush 52

Aspen 2

* Barren areas often contain sparse herbaceous vegetation and occasional small trees or shrubs.

4.3.2 Regional Context

Lassen contains a great variety of vegetation partly because it lies at the confluence of the

Cascade Range, the Sierra Nevada, the Great Basin, and Klamath regions. The importance of the

Klamath Region as a floristic center of diversity for western North America has been recognized 

in classic papers by Whittaker (1960, 1961) and Stebbins and Major (1965). This diversity is 

paralleled in other life forms, leading to the area being highlighted for its global biodiversity 

significance (DellaSala et al. 1999). The biological wealth of the region is generally attributed to 

the remarkable array of geologic parent materials and climates present (Wallace 1983). The 

young volcanic landscapes at Lassen contribute a unique element to this geological and 

corresponding biological diversity. The Lassen area also contains significant subalpine and 

alpine habitat. These are common in the Sierra Nevada to the south and Cascades to the north, 

and Lassen’s subalpine habitats provide a stepping stone between these two large areas of high 

elevations. Disturbances such as fire have also been instrumental in promoting vegetation 

diversity across the region (Taylor and Skinner 1998, Odion et al. 2004). 
37

4.3.3 Issues Description

Issues pertinent to vegetation composition, structure, and function at Lassen include: 1) fire 

regimes, fire suppression and fuels management, 2) vegetation succession, 3) invasive plants, 

and 4) invasive pathogens. These are now discussed. In addition, impacts to vegetation from 

atmospheric pollution are discussed briefly in section 2.5.

4.3.3.1 Fire Regimes, Fire Suppression, and Fuels Management

Like most other forests of western North America, fire is a keystone ecological process at Lassen 

and in the surrounding environs of the southern Cascades (Taylor 2000, Bekker and Taylor 2001, 

2010, Beaty and Taylor 2001). Also, as with many other western North American forested 

landscapes, there is a very high level of concern about the long-term effects of fire suppression 

and fire management in Lassen. The impacts of fire suppression and fire management are key 

components of this condition assessment. To assess the impacts requires understanding of the 

historical reference conditions for fire regimes at Lassen. 

At many low- to mid-elevation forests in the western USA there are very strong concerns that 

fire suppression has led to substantially increased susceptibility of forests to uncharacteristically 

severe fire. However, Lassen contains mid-to upper elevation forests, and it is uncertain how the 

susceptibility to fire has changed in these forests. Susceptibility to uncharacteristically severe fire 

is related to both changes the likelihood of fire and the likely severity of fire that occurs. 

Evaluating whether forests are more susceptible or not to severe fire depends on the historic fire 

regime. Where a low-severity regime operated, fires were frequent (<20 year recurrence interval)

and this limited fuels and fire severity. Fire suppression has greatly reduced the likelihood of 

low-severity fire where low-severity fire regimes occurred historically, but the probability of

high severity fire may have increased, as shown in Figure 7. 

Figure 7. Hypothetical changes in the amount of higher and lower severity fire with fire suppression 

where a low-severity fire regime and steady-state conditions historically occurred. 

Prior to fire suppression After fire suppression

Amount of fire

higher severity fire lower severity fire
38

In mixed-severity fire regimes (Baker et al. 2007: Table 1, Perry et al. 2011), fire operated in a 

patchwise and irregular fashion to cause instability of forest populations through disturbance, 

causing significant turnover in stands, or new stand initiation (Whittaker 1960). The effect of fire 

suppression in this case has been to generally reduce amounts of all fire: low-, moderate- and 

high-severity (Figure 8).

The transition between low- and mixed-severity fire regimes affected so differently by fire 

suppression may occur at elevations within Lassen National Park. We therefore evaluate the best 

evidence available to determine which historical fire regime occurred in different portions of the 

park in order to assess the changes in forest susceptibility to severe fire that have occurred with 

fire suppression.

Figure 8. Changes in the amount of higher and lower severity fire with fire suppression under a historical

model of mixed severity fire.

4.3.3.2 Climate Change and Fire

Changes to fire regimes that may be ongoing or occur in the future are particularly hard to

predict due to ongoing climate change. Fire frequency in the Pacific Northwest has been found to 

track the Pacific Decadal Oscillation (PDO), at least since fire suppression became effective 

(Heyerdal et al. 2008, Morgan et al. 2008). PDO oscillates on a frequency of about 25 years. 

From the 1970s until recently, PDO has been in the warm phase, but has recently shifted to a

cool phase (Mantua 2000) particularly in the last four to five years 

(http://cses.washington.edu/cig/pnwc/aboutpdo.shtml). Thus, in the absence of other climate 

factors, fire in the Pacific Northwest should occur at lower amounts for the next couple of 

Prior to fire suppression After fire suppression

Amount of fire

higher severity fire lower severity fire
39

decades than it did in recent decades. However, the future behavior of PDO may be altered by 

climate change. 

In terms of actual patterns in fire occurrence under changing climate, Miller et al. (2009) and 

Miller and Safford (2012) found that the severity of fires in the Sierra Nevada region has been 

increasing since 1984. Their study area included the Lassen area. However, these two studies 

used modern vegetation maps to identify forests that had burned. This approach will introduce a 

trend unrelated to fire severity that can make it appear that severity is increasing when it is not. 

This is because high severity fire causes forests to transition to early successional vegetation, 

such as chaparral. A current map may not identify areas of forest that burned at high severity in 

the past because such areas would currently be mapped as chaparral. This has the effect of 

deleting some of the conifer forest that experienced high-severity fire in the early years of the 

time series since 1984, but has not yet returned to conifer forest through natural succession. The

result is that the amount of high-severity fire in conifer forest in the earlier years of the time 

series may be underestimated, creating the false appearance of an upward trend. Therefore, 

Miller et al. (2012) emphasize the need to use pre-burn vegetation mapping in assessing fire 

severity trends. Without such a trend analysis, the ongoing fire trends in the Lassen region 

remain uncertain. It should be noted that this region has seen some exceptionally severe fires in 

recent decades, such as the Moonlight Fire of 2007 and the Fountain Fire of 1993. However, 

large areas of dense, even-aged plantations burned in these two fires. Plantations are known to 

burn with much greater severity than unmanaged forests (Odion et al. 2004). This effect needs to 

be taken into account, along with weather, in explaining the behavior of these two extreme fires.

4.3.3.3 Vegetation Succession

Fire suppression can have a major influence on vegetation structure, composition, and function. 

The historic fire regime, with large amounts of moderate and high severity fire (Beaty and Taylor 

2001, Bekker and Taylor 2001, 2010), would have favored the maintenance of aspen, Jeffrey 

pine, lodgepole pine, and chaparral. Historically, the establishment and maintenance of these 

vegetation types likely depended on mixed-severity fires that created patches of early 

successional vegetation. Aspen, pines, and chaparral species do not typically reproduce 

continuously under steady state conditions; they reproduce following stand-replacing events, 

mainly fire. Removing the regeneration niche for these vegetation types may therefore threaten 

their persistence on a site, although they may be resilient and come back if fire does eventually 

return.

There are concerns about loss of early successional vegetation at Lassen, in particular, aspen. 

Aspen (Populus tremuloides) is well-recognized as an early successional and disturbance 

dependent species in coniferous forest landscapes (Pierce and Taylor 2010). Growth of conifers 

into aspen stands in the absence of fire is a successional change that has been described in the 

southern Cascades by Pierce and Taylor (2010), and in Lassen by McCullough et al. (2012). 

Aspen may create an environment that facilitates conifer growth. For example, growth rates of 

conifers have been found to be faster in aspen stands than pure conifer stands (Peterson and 

Squiers 1995a,b). Once overtopped, the shade intolerant aspens release resources to conifers. 

Aspen do not maintain dormant seed banks and often reproduce by sprouting from roots. Thus, 

resiliency to long fire-free periods depends on the lifespan of root systems in declining stands as 

well as the availability of seed to disperse from surrounding areas. Reproduction from seed has 

been found to be common after high severity fire, even where no aspens were nearby (Romme et 
40

al. 2005). However, aspen have decreased in the area around Lassen as well. Establishment of 

aspen from seed is highest in the most severely burned areas. Greater fire severity not only 

promotes aspen seedling establishment, but helps prevent conifers from surviving in the stand to 

compete with the young aspens. At Yellowstone, the conifers killed by fire were also a key to 

survival of young aspens because downed branches and logs from these trees helped inhibit 

ungulate browsing (Ripple and Larson 2001, Turner et al. 2003). The ecology of aspen makes 

fire the best tool for restoring stands because mechanical removal of conifers could reduce the 

flammability of the stand, favoring conifers in the long run, and because removing the conifers 

will preclude their post-fire role in protecting young aspen growth. 

Chaparral, like aspen groves, may be relatively quickly replaced by conifers in montane zones if 

not maintained by fire (Wilken 1967, Odion et al. 2004, 2010a, Nagel and Taylor 2005). Conifer 

succession may be facilitated by chaparral shrubs which reduce drought stress on conifer 

seedlings (Zavikovski and Newton 1968), and through provision of mycelia of mycorrhizal fungi 

shared with Arctostaphylos (Horton et al. 1999). Conifer succession may also be aided by the 

nitrogen fixing capacity of chaparral shrubs in the genus Ceanothus (Busse et al. 1996). 

However, the shrubs maintain dormant seed banks that can remain viable for centuries or 

millennia (Quick and Quick 1961), while manzanita seeds may be dispersed by mammals, which 

eat the berries. Thus, chaparral can be replaced by conifers on a site, but still be resilient 

following stand-replacing fire. However, the lack of chaparral over much of the landscape due to 

fire suppression means that species that are associated with chaparral for example birds and 

insects, along with the shrubs themselves will be present at much lower than characteristic 

amounts.

Like aspen groves and chaparral, meadow vegetation is shade intolerant and may be subject to 

establishment of conifers. While conifer encroachment into montane meadows is likely 

associated with reduced fire frequency (Taylor 1990), damage from historic grazing has also 

been a likely cause In fact, it may be difficult to separate historic grazing effects in meadows 

from effects of fire suppression because fire may not have burned nearly as frequently in 

meadows as adjacent forests. There are records of meadows burning from lightning fires, but 

they are rare (DeBenedetti and Parsons 1979). But this is related, at least in part, to fire 

suppression. It is not known how often historically fires burned from forests into meadows and 

then stopped; this cannot be determined from fire scars. 

Soil compaction and erosion from livestock can cause downcutting in meadows along drainages 

and small streams. This can lower the water table such that the soil does not remain saturated to 

near the surface during the growing season, promoting conifers, as described for Sierran 

meadows (Wood 1975, Vankat and Major 1978, DeBenedetti and Parsons 1979, Odion et al. 

1988, Sarr 1995). This can be a subtle effect; it need not require deep meadow incision. It may 

be exacerbated by removal of beavers. Conifers can more readily grow on the meadow margins 

when the water table is lowered. Conifer succession may also be facilitated by burrows of 

fossorial mammals (marmots, voles), which bring mineral soil to the surface. Conifer 

germination and initial survival may depend on these environments. 

An additional concern about fire suppression impacts involves forest vegetation. There has been 

a shift towards increasing forest dominance by shade tolerant fir species (Taylor 2000). With 

periodic fires, establishment of firs and growth into the forest overstory would have been more 
41

limited than it is with fire suppression. This effect is most common in western forests where fire 

suppression and historical logging have both occurred (Naficy et al. 2010), but could also have 

been facilitated by historical grazing. Increased atmospheric CO2 could be related to increased 

forest density as well; growth rates of trees in drier western coniferous forests have increased due 

to CO2 (Soulé and Knapp 2011). Forests in the Pacific Northwest, particularly in upper montane 

zones, have increased growth rates in recent decades (Latta et al. 2010), despite warming 

temperatures.

4.3.3.3 Invasive Plants

Non-native, invasive species are a significant threat to native plant communities in virtually all 

natural areas and threaten the core goals of the National Park Service. Not surprisingly, invasive 

plants ranked as the top vital sign for monitoring within the Klamath Network. In many regions, 

invasive species are second only to habitat loss as a threat to native biodiversity (Wilcove et al. 

1998). Impacts from invasives that can severely degrade native ecosystems include the 

replacement of native vegetation (Tilman 1999), the loss of rare species (King 1985), changes in 

ecosystem structure (Mack and D’Antonio 1998), alteration of nutrient cycles and soil chemistry 

(Ehrenfeld 2003), shifts in community productivity (Vitousek 1990), changes in water 

availability (D’Antonio and Mahall 1991), and alteration of disturbance regimes (Mack and 

D’Antonio 1998). 

While not all non-native species are invaders that threaten native species, across the Klamath 

Network the number of non-native species declines sharply from low elevations of Whiskeytown

to the higher elevations at Lassen (Figure 9). This pattern has been well-established in other 

studies in California (Mooney et al. 1986, Rejmanek and Randall 1994, Schwartz et al. 1996, 

Keeley et al. 2011). The question here is: Does this mean that Lassen may be relatively immune 

from invasive plants?
42

Figure 9. Non-Native Plant Species Richness as a Function of Park Area and Elevation in the Klamath

Network. A logarithmic line illustrates the expected species/area relationship across park sizes, and oval

size is proportional to mean park elevation. The lower elevation parks have more nonnative species than

expected for their size, whereas higher elevation parks have fewer recorded species.

We reviewed the physiological tolerances of invasive plants that are present or expected in all 

Klamath Network Parks (Odion et al. 2011, Odion and Sarr 2012). We found that Lassen may be 

more vulnerable to invasive plants that are ecosystem transformers than the current low levels of 

invasion may suggest. The analysis appears to support concerns about invasive plants at Lassen 

and the use of invasive plants as an indicator of ecosystem condition in this park. The invasive

species of greatest concern that are still controllable because they have not established are shown 

in Table 5. Equilibrium species, some of which will be subject to control efforts if found in 

backcountry areas, are shown in Table 5.

0

50

100

150

200

250

300

0 20,000 40,000 60,000 80,000

Park Area (ha)

Non-native Species

Oregon Caves

Lava Beds

Redwood

Lassen Volcanic

Crater Lake

Whiskeytown

0

50

100

150

200

250

300

0 20,000 40,000 60,000 80,000

Park Area (ha)

Non-native Species

Oregon Caves

Lava Beds

Redwood

Lassen Volcanic

Crater Lake

Whiskeytown
43

Table 5. Invasive plants of greatest concern at Lassen National Monument as determined by the

prioritization process used by the Klamath Network and involving park resource staff (Odion et al. 2011). 

The ranking is based on a semi-quantitative 0-1 score. The species on this list are invaders that are

considered capable of transforming ecosystems. Species in the colonization phase may have been

recorded, but are not yet established in the park. Species in the establishment phase have one to a few

relatively small, localized populations within Lassen Volcanic National Park.

Scientific Name Common Name Invasion Phase Ranking Score

Taeniatherum caput-medusae Medusahead Colonization 0.920

Lythrum salicaria Purple Loosestrife Colonization 0.901

Genista monspessulana French Broom Colonization 0.895

Cytisus scoparius Scotch Broom Colonization 0.875

Centaurea solstitialis Yellow Starthistle Colonization 0.873

Euphorbia esula Leafy Spurge Colonization 0.866

Centaurea maculosa Spotted Knapweed Colonization 0.854

Onopordum acanthium Scotch Thistle Colonization 0.848

Bromus tectorum Cheatgrass Establishment 0.827

Rubus armeniacus Himalaya Berry Establishment 0.823

Lepidium latifolium Broadleaved Pepperweed Establishment 0.812

Phalaris arundinacea Giant Reed Grass Establishment 0.798

Halogeton glomeratus Halogeton Colonization 0.789

Isatis tinctoria Dyer’s Woad Colonization 0.770

Carduus pycnocephalus Italian Thistle Colonization 0.769

Hirschfeldia incana Mediterranean Mustard Colonization 0.755

Centaurea diffusa Diffuse Knapweed Colonization 0.750
44

Table 6. Equilibrium species in Lassen Volcanic National Monument and status of species which will or 

will not be monitored in the backcountry by the Klamath Network Inventory and Monitoring Program.

Scientific Name Common Name Ranking Score Monitor in Backcountry?

Cirsium vulgare Bull Thistle 0.679 Yes

Verbascum thapsus Common Mullein 0.655 Yes

Tragopogon dubius Goat’s Beard 0.595 Yes

Vulpia myuros Vulpia 0.550 No (control infeasible)

Poa pratensis Kentucky Bluegrass 0.530 No (control infeasible)

Lactuca serriola Wild Lettuce 0.496 No (control infeasible)

Taraxacum officinale Dandelion 0.494 No (control infeasible)

Poa annua Annual Bluegrass 0.421 No (control infeasible)

Plantago lanceolata English Plantain 0.414 No (control infeasible)

Plantago major Common Plantain 0.404 No (control infeasible)

4.3.3 4 Extent of Invasive Pathogens (Condition of Subalpine Vegetation

The outstanding non-native species and plant pathogen of concern at Lassen is the blister rust

fungus (Cronartium rubicola). It is the only plant pathogen we treat in this condition assessment, 

although it is important to note that there may be more pathogens arriving in the future. Blister 

rust is the main factor impacting the condition of the park’s subalpine vegetation, particularly 

whitebark pine, which was a top management concern raised by the park. The Klamath Network 

identified whitebark pine as a vital sign of ecosystem health to monitor and has initial monitoring 

results (Smith et al. 2011, Erik Jules, pers. comm.).

Blister rust forms rusty looking lesions, or cankers, of dead tissue that girdle tree boles or stems.

The rust affects 5-needle white pines; at Lassen, these include not only whitebark pine, but sugar

pine (Pinus lambertiana) and western white pine (P. monticola). Present concerns are mainly the 

impacts to whitebark pine. Impacts to the other species have already occurred and are no longer a 

major concern.

To complete its life cycle, the rust fungus must disperse from the pines to an alternate host, a 

shrub in the genus Ribes (currant and gooseberry) or the herbs Castilleja (Indian paintbrush) and 

Pedicularis (lousewort) (Geils et al. 2010). Removal of alternative hosts is one approach that has 

been taken in an attempt to manage the disease, with generally little success and with potentially 

adverse effects on important wildlife species. 

Preliminary assessments of 2012 monitoring data suggest that blister rust infections may be more 

common than previously believed at Lassen. Jules et al. (2012) found that white pine blister rust 

infected 53% of whitebark pine at Lassen. Future monitoring by Dr. Jules and colleagues, in 
45

collaboration with the Klamath Network Inventory and Monitoring Program, should help clarify 

the status and trends in blister rust in whitebark pine.

Concern about blister rust in whitebark pine stems from its role as both a foundation and

keystone species in high-elevation forest communities where it dominates. It can regulate

ecosystem processes, community composition and dynamics, and it influence regional 

biodiversity (Tomback and Kendall 2001, Ellison et al. 2005). Whitebark pine plays a role in 

initiating community development after fire, influencing snowmelt and stream flow, and 

preventing soil erosion at high elevations (Farnes 1990, Tomback et al. 2001). Perhaps most 

importantly, the large, wingless seeds of whitebark pine are high in fat, carbohydrates, and lipids 

and provide an important food source for many granivorous birds and mammals (Tomback and 

Kendall 2001). In particular, Clark’s nutcracker (Nucifraga columbiana) has developed a 

mutualistic relationship with the pine (Tomback et al. 2001). Nutcrackers decrease in whitebark 

stands as tree mortality increases (McKinney et al. 2009). Whitebark pine also provides 

important habitat structure for high-elevation vertebrates. For example, white-tailed jackrabbits

(Lepus townsendii) have been documented using dense, low-growing whitebark pine mats for

shelter in the Sierra Nevada. This once common mammal has become rare in the Sierra Nevada, 

the southernmost portion of its range (http://www.sibr.com/mammals/M050.html)

Smith et al. (2011) discuss possible implications of climate change for future levels of blister 

rust. They suggest that such implications could be quite complex because they may operate 

through both direct and indirect mechanisms. There are also complicating factors. In particular, 

warmer temperatures in recent years have allowed mountain pine beetles (Dendroctonus 

ponderosae) to shift to and persist in higher-elevation forests (Logan 2010). Murray (2010) 

reported that mountain pine beetle is now the primary cause of whitebark pine mortality at Crater 

Lake National Park, and it appears that this is the case at Lassen as well (Jules et al. 2012). 

Whether the beetle affects the susceptibility of whitebark pines to blister rust, or vice versa, is 

not known. Bockino and Tinker (2012) found that whitebark pine trees which were selected as 

hosts by mountain pine beetles exhibited significantly greater blister rust severity than trees that 

were not selected. Other indirect effects could occur if climate increasingly favors or inhibits 

blister rust. For example, the rust favors moister conditions, and increased precipitation in winter 

is a possible trend under climate change in the Pacific Northwest. Direct effects of climate could

favor the pines, as many high-elevation trees are growing more rapidly today (Bunn et al. 2010).

However, more rapid growth of other high-elevation tree species could act as an indirect effect

that places the pine at a competitive disadvantage, especially if whitebark pine cannot migrate

quickly enough to avoid being displaced by superior competitors with more rapid growth

potential, such as mountain hemlock (Tsuga mertensiana) and noble fir (Abies procera). These 

trees are quite dense in many whitebark pine stands.

4.3.3.5 Rare Plant Species and Species Diversity

Many plant species are rare within the park but are found rather widely outside the park 

boundaries. Others that occur within the park are rare throughout the region and thus are major 

contributors to biodiversity measured at a landscape or regional scale. Some Lassen species will 

be lost through natural processes that influence species turnover, while the unintentional loss of 

others could occur directly or indirectly as a result of climate change or management practices. 
46

Vegetation in the park may also be sensitive to elevated levels of ozone and to deposition of 

atmospheric nitrogen and sulfate. These are discussed in section 2.5.

4.4 Indicators and Criteria to Evaluate Condition and Trends in Vegetation

Table 7 shows the indicators of vegetation structure, function, and composition that were chosen

for use in this NRCA to evaluate condition and trends in the park’s vegetation.

Table 7. Vegetation indicators and the ecological conditions for which they are indicators.

Indicator Conditions Tracked

Stand age distributions Fire regimes, vegetation dynamics

Fire rotations Fire regimes, vegetation dynamics

Abundance of major vegetation types Broad vegetation types

Invasive plants Vegetation/ecosystem transformation

Invasive pathogens Vegetation/ecosystem transformation

Rare plants and diversity of native plants Climate change, natural succession

4.3.4.1 Distribution of Stand Age Classes

The distribution of stand ages in a landscape that has not been logged can illustrate whether lowor mixed-severity fire regimes occurred historically (Figures 7, 8), and the departure from 

historic vegetation structure as shaped by fire. Using the stand age distributions as a measure of 

vegetation condition is consistent with recommendations for using a statistical distribution to

describe reference conditions for an indicator rather than relying on mean or median values 

(Stoddard et al. 2006). A comparison on the current distribution of stand ages with a distribution 

unaffected by fire suppression provides an explicit illustration of how stand ages have changed 

with fire suppression. When coupled with an understanding of vegetation succession, the 

changes in vegetation age provide a model of landscape change. 

Figure 10 shows the stand-age distributions that would exist where a low-severity regime 

historically occurred. In this distribution, most stand ages reflect the maximum lifespan of trees 

because stand-initiation by fire has not occurred. Therefore stands will mostly be several 

centuries old. However, an increase in fire severity due to fire suppression in recent decades 

would lead to some young stands being created, as also shown in Figure 10. Conversely, Figure 

11 shows the stand-age distribution that would exist where mixed-severity fire regimes occurred 

historically. Prior to fire suppression, stand-initiation would have occurred continuously, creating 

mostly stands whose initiation occurred in the decades prior to fire suppression. The effect of 

younger stands in erasing older stands causes a long statistical tail, with relatively few stands as 

old as the ones that dominate in a low-severity regime. 
47

Figure 10. Theoretical stand age distribution in forests affected by a low-severity fire regime and an 

increase in susceptibility to more severe fire in recent decades due to fire suppression.

Figure 11. Hypothetical stand age distribution for forests affected by a mixed-severity fire regime and 70-

90 years of reduced fire due to fire suppression. 

10 50 90 130 170 210 250 290 330 370 400+

Percent of landscape (%)

Stand age class

0

2

4

6

8

10

12

14

16

18

20

10 50 90 130 170 210 250 290 330 370

Percent of forestlands

stand age
48

Criteria

Good condition would be current stand ages in unlogged areas that appear to be similar to 

historical stand ages. Little effect of fire suppression would be apparent in the age class 

distribution. Somewhat Concerning would be stand-ages moderately altered by fire suppression. 

Significant Concern would be stand-ages substantially altered by fire suppression. 

Condition and Trends

The condition and trend for the stand age indicator are rated Significant Concern. Stand age

analyses indicate that mid-to upper elevation forests in the southern Cascades and nearby Sierra 

Nevada were shaped by mixed severity fire because stands were initiated continuously prior to 

fire suppression (Figure 12).The substantial reduction in stand-initiation with the onset of fire 

suppression in the early 1900s is consistent with fire being a dominant process causing standinitiation, otherwise we would expect little impact of fire suppression on stand ages. The 

occurrence of a mixed-severity fire regime is also supported by literature reviewed in the next 

section (Beaty and Taylor 2001, Bekker and Taylor 2001, 2010, Hessburg et al. 2007, Baker 

2012), and the loss of early successional vegetation as described in section (4.3.4.3).

Since the onset of fire suppression, landscape vegetation patterns have been shaped far less by 

fire. Figure 12 clearly shows that the probability of stand-initiation by fire is much lower with 

fire suppression than it was historically. As a consequence, stands younger than 80 years are 

currently substantially underrepresented compared to a scenario in which fire suppression never 

occurred (gray bars), while, stands 80-200 years are overrepresented. With no fire suppression, 

many of these intermediate-aged stands would have been erased by more recent stand-initiation 

fires. Stands over 200 years are about the same as occurred historically. 

Certainty is rated as medium because we relied on regional data rather than data specific to the 

park. To obtain a large enough sample size of stand age data, we used data from U.S. Forest

Service Inventory and Analysis (FIA) plots from lands that have never been managed for timber

production throughout the southern Cascades and nearby Sierra Nevada (see Appendix C for 

methodological details). ). Only plots from the same forest types were selected, and these 

occurred in similar proportions as the forest types occur presently in Lassen (Appendix C).Fire

regimes in areas protected from timber management in this region, like those in this park, have

been affected by similar disturbance regimes, as well as fire suppression management as has 

occurred in the park. Nonetheless, there may be important differences between the park and 

neighboring areas supporting the same forests. For example, the existence of barren areas (e.g., 

historic lava flows, etc.) at Lassen could reduce historical fire frequency and severity in some 

areas.
49

Figure 12. Never-managed forest stand age distribution in the upper montane zones of the eastern 

Cascades (black bars), compared with the theoretical distribution that would be present had presuppression fire disturbances not been interrupted by fire suppression (gray bars).

There are a variety of ecological effects caused by the suppression of mixed-severity fire. Lack

of mixed-severity fire leads not only towards older age class distributions, but also greater 

homogeneity as younger age classes are diminished and intermediate-aged stands become 

overrepresented compared to historical stand age structure. Suppression of mixed-severity fire 

also leads to a lack of complex early successional vegetation created by fire (e.g., Swanson et al. 

2011). Thus, chaparral, Aspen forests, and young conifer forests have been lost. These are major 

resource management concerns already identified by the park.

For fire and stand age conditions to reverse themselves and the former patterns to return, an

order of magnitude more wildfire than presently occurs over a period of about 80 years would 

need to occur (see next section on fire rotations). About half of all forests in the park would have

to burn with stand-initiating fire over that time. Planned prescribed burns are very constrained in

area and are mostly limited to surface fires. Logging does not recreate complex early seral 

conditions, down wood to protect aspens from undulates, standing snags and down wood to 

promote aspen growth and wildlife, and it raises complex ethical issues in a National Park.

Wildland fire use (allowing unplanned fires to burn) is also constrained for pragmatic reasons 

(see discussion above in section 2.4.3.1). Thus, the trend of greatly reduced mixed-severity fire 

and stand-initiation will likely continue. In addition, much park fire management aims to reduce 

the behavior of fire, which would further move conditions away from those that occurred 

historically. However, the effects of fire suppression and fuels management in reducing mixedseverity fire might be reversed, at least in part, by the effects of climate change, although there is 

much uncertainty about how this will play out (see discussion above in section 4.4.3.1).

0

1

2

3

4

5

6

7

8

9

10 50 90 130 170 210 250 290 330 370 400

number of plots

Stand age class (10 year intervals)

Existing stand age

Stand age with no fire suppression

4 per. Mov. Avg. (Existing stand age)
50

Assessment Confidence and Data Gaps

Medium. As mentioned above, most of the available information about past range of variation in

stand ages comes from an area that is much broader than the park. In addition, as with nearly all 

ecological changes, there are both detrimental and beneficial effects. Suppression of fire is 

unnatural, but does lead to more area of dense, late-successional forest, which benefits species 

like northern spotted owls and fishers. 

The assessment based on this indicator is also limited by the fact that stand ages are

approximations. Some older stands may not have been initiated by fire disturbances and

estimates of their ages may have been based on trees that germinated without disturbance.

Nonetheless, the shift in age classes due to fire suppression is quite substantial and not a function 

of age uncertainty of old stands. The general effects of fire suppression indicated by stand age 

analysis are consistent with expectations from literature on historical fire regimes in the eastern 

Cascades and southern Cascades (Hessburg et al. 2007, Beaty and Taylor 2001, Bekker and 

Taylor 2001, 2010, Baker 2012). 

Future amount of stand-initiating fire will be monitored under the land-use, land cover protocol 

of the Klamath Network Inventory and Monitoring program. Monitoring status and trends in the 

amounts of early successional vegetation is difficult with plot data because a large number of 

plots randomly located throughout the park would be required. There is no plot monitoring 

program in the park that accomplishes this.

Another approach to assessing the loss of mixed-severity fires is to use a species which depends 

on early successional habitat created by such fire, such as the black-backed woodpecker. This 

species is a management indicator for the National Forests of the Sierra Nevada region that

surround Lassen. We describe park conditions based on this indicator in the wildlife section

(2.2.4.1). In addition, the next two indicators provide information about altered fire regimes and 

resulting consequences to vegetation.

4.3.4.2 Fire Rotations

The fire rotation is the amount of time needed to burn an area of interest one time. It is

equivalent to the mean fire frequency for the entire landscape of interest. These properties make 

the fire rotation the best measure for comparing rates of fire across landscapes or time periods 

(Baker 2009, Miller et al. 2012). The fire rotation for a landscape often differs from the mean fire 

interval, or frequency of fire, estimated from fire scars somewhere within that same landscape.11

 

11 This can occur because the fire scars are rarely probabilistic samples (i.e., the target population they 

provide inference for is, except in a few cases, not the whole landscape ; Johnson and Gutsell 1994), and 

they are usually sampled from small areas. In addition, the frequency of fire measured from fire scars is a 

composite of fires that each differ in the amount of area burned and the area is often unknown. In such a 

composite measure of fire frequency, the frequency increases by increasing the area studied. For 

example, in studies of Jeffrey pine in Baja California, Minnich et al. (2000), found a fire rotation or mean 

fire interval for the landscape of 52 years. A fire scar study in the same landscape found a fire frequency 

of about 16 years over the same time period (Stevens and Olsen 2004). Therefore we use fire rotation 

here as a standard that allows comparison of the specific amount of fire affecting a landscape over time.
51

The rotation is estimated by summing the areas of fires observed over the specified area and 

period of time, then dividing the period of time by the fraction of the specified area that burned. 

For example, if 1000 hectares of a 3000 hectare area burns in 20 years, the fire rotation is 

calculated as: 20 years/(1000/3000) or 60.6 years. Typically, some of the areas that burned will 

have burned more than once and other areas not at all. The fire rotation can be calculated for 

particular kinds of fire, such as low or high severity fire (Odion and Hanson 2006) and can also 

be estimated from stand age data (Johnson and Gutsell 1994).

We calculated current rotations of fire since 1984, the earliest year available from the 

“Monitoring Trends in Burn Severity” (MTBS) program, to compare with fire rotations from 

prior to fire suppression. We also calculated the rotation for high severity fire. We obtained fire 

severity data from the federal website MTBS.gov. We used data from 13 fires that occurred in 

Lassen or within 30 km of Lassen. We included area outside the park because relatively little fire 

severity data from Lassen was available. 

Criteria

“Good” condition would be current fire rotations that appear to be similar to historical fire 

rotations. There would be little effect of fire suppression apparent on the length of fire rotations. 

“Somewhat Concerning” would be rotations moderately altered by fire suppression; “Significant 

Concern” would be rotations substantially altered by fire suppression. 

Condition and Trends

Both condition and trend for this indicator are rated Somewhat Concerning – Medium Certainty. 

Since 1984, a total of 19,260 ha have burned in the park out of 38,847 ha of burnable vegetation 

(mainly forest). The rotation over this time period is therefore (28 years/19260/38,847) = 56 

years. Notably, prior to the occurrence of the Reading Fire in 2012, the fire rotation was 

considerably longer: 85 years. The park’s condition benefited from this fire and management that 

allowed it to cover as much area as it did. 

Table 8 shows pre-suppression rotations calculated from landscapes near Lassen. A 56 year 

rotation is slightly longer than the ranges calculated for all fire in mid-montane forests in these 

nearby landscapes and within the range for upper montane forests. Moreover, expanding the time 

period of reference would broaden the range of variability in past fire (Whitlock et al. 2010). The 

current rotation may therefore be within a more expansive natural range of variation for midmontane forests and well within the historical range for upper elevations. 

There are specific locations where more frequent occurred historically as measured by fire scars 

(e.g., Table 8: Point Fire return intervals). There are no areas of the park, except perhaps some 

prescribed burn units, where such repeat surface fires have occurred. However, it is impossible to 

know the locations in the landscape to which the frequent surface fire locations may apply 

(Johnson and Gutsell 1994)12.

 

12 These are not probabilistic samples of the whole landscape because not every tree/location has an equal 

probability of being sampled because certain trees must be selected (Johnson and Gutsell 1994). The samples best 

describe the area immediately around the point location. Statisticians for the Inventory and Monitoring Network 

encourage greater reliance on data collected by probabilistic sampling when making inferences especially at a 

landscape scale (see Stevens and Olsen 2004).
52

Table 8. Mean fire frequency prior to fire suppression from studies in the northern Sierra Nevada and 

southern Cascades.

Forest Zone Forest Types

Fire Rotation 

Interval from 

Mapped Fires (yrs)

Point Fire 

Return Interval 

(yrs) Source

Mid-montane

white-fir, sugar pine, 

Jeffrey pine 22-50 7-55 Bekker and Taylor (2001)

white fir, ponderosa 

pine, red fir 17-43 5-108 Beaty and Taylor (2001)

Mid-upper 

montane

white-fir, Jeffrey pine, 

red-fir 46-147 4-91 Bekker and Taylor (2001) 

Jeffrey pine, white fir, 

red fir (Prospect Peak, 

Lassen NF)

17.1-75.9 9.5-109 Taylor 2000

We estimated a high severity rotation of 784 years since 1984. This can only be considered a 

rough estimate of the amount of high-severity fire presently occurring in the park. Notably, the 

high-severity rotation would have been 1177 years without the Reading Fire. The 784 year 

estimate is, however, consistent with the calculation of the rotation based on stand-initiation 

from the stand-age data, which was 700-800 years over the time period 1940-2009.

The high severity fire rotation is more than twice as long as the rotation for high severity in the 

two nearby studies by Taylor and colleagues which provide the best published information on the 

pre-suppression variability in fire behavior13 (Table 9). The current high severity rotation is also 

more than twice as long as the 155 year historic high-severity rotation calculated from the stand 

age data. It is possible that wildfires have been more severe in Lassen than surrounding areas 

from which much of the fire severity data originate (meaning our rotation estimate is high). 

However, much of the fire in Lassen since 1984 (40% since 1989) has been prescribed fire, 

which is generally low severity. Thus, it is possible the rotation is short (i.e., there is actually less 

high severity fire since 1984). The rotation is consistent with the finding that stand-initiating fire

in the region is much less frequent than it was historically, as illustrated by the near cessation of 

stand-initiation (Figure 12). This is also consistent with concerns about loss of early-successional 

vegetation like aspen and chaparral.

 

13 The amount of moderate and high severity fire they found over a specified time period of analysis can 

be used to calculate the rotation of moderate and high severity fires prior to fire suppression, which can 

be compared with modern rates of such fire. The rotation is calculated as the number of years moderate 

and high severity fire were detectable divided by the percentage of the landscape burned by moderate 

and/or high severity fire.
53

Table 9. Fire rotations from studies of small landscapes in the southern Cascades adjacent to Lassen 

National Park. 

Study Location 

and size (km2) Source Forest Type Type of Fire

Pre-suppression 

Rotation (years)

S. Cascades 

near Lassen

Bekker and 

Taylor 

(2001)2

Jeffrey pine, white 

fir, and 

red fir

Low severity‡ 24-91

High/moderate severity† 111-225

High severity* 165-210

S. Cascades 

near Lassen

Beaty and 

Taylor 

(2001)3

Mixed conifer, 

white fir, red fir, 

Douglas-fir and 

ponderosa pine

Low severity‡ 19-89

High/moderate severity† 83-114

High severity* 101-394

*”High severity” <10 emergent trees/ha remaining after fire.

†High” and “moderate” severity = <20 emergent trees/ha remaining after fire, which may be considered 

high severity fire according to many definitions.

‡Low severity rotation obtained by subtraction of the high and moderate severity rotations from the 

rotation for all fire (the percentage of the landscape affected by low severity fire does not include any low 

severity fire that may have occurred in areas that burned at moderate and high severity).

2

High and moderate severity rotation based on proportion of landscape affected from 1864-1939. These 

fires occurred predominantly in the 1800s. The 75 year time period from 1864-1939 started and ended on 

large fires. This time period was therefore bracketed by 1⁄2 of an average rotation interval for all fire (33 

years) to produce a 109 year time period/fraction burned to calculate rotation. The range in rotations 

reflects the minimum and maximum rotations from different forest types (Table 2 of Bekker and Taylor 

2001). 

3

High and moderate severity rotation based on proportion of landscape affected from 1883-1926 (fires 

were consistent through this whole period). The 43 year time period from 1883-1926 started and ended 

on a large fire this time period was bracketed by 1⁄2 of an average rotation interval for all fire (28.2 years) 

to produce a 71 year time period/fraction burned to calculate rotation. The range in rotations reflects the 

minimum and maximum based on different slope/aspect categories (Table 8 of Beaty and Taylor 2001). 

Both Bekker and Taylor (2001, 2010) and Beaty and Taylor (2001) found that, over only several 

decades to a century, most area had been affected by fires where fewer than 20 emergent trees/ha 

could be observed. Although 10-20 emergent trees was considered “moderate severity,” this 

would still be consistent with stand-renewing fire in forests where up to several hundred 

remaining trees/ha may be the norm. Bekker and Taylor (2010) in particular emphasize the 

dominant role played by severe fire with high levels of tree mortality. 
54

As discussed in the previous section, the suppression of low-, moderate-, and high- severity fire 

will cause a loss of earlier successional vegetation and age class diversity. In addition, older pine 

stands become increasingly dominated by shade-tolerant firs. These changes are evident from the 

comparison of the 1930s historic vegetation map and more current mapping (see section 4.3.4.3). 

In addition, the dead trees created by high severity fire are important disturbance legacies for 

biodiversity that also reduce the environmental stress and magnitude of a disturbance (Odion and 

Sarr 2007). In particular, the standing dead trees left by fire are critical for species such as blackbacked woodpecker, an indicator used in this assessment.

For high-severity fire rotations to return to more historical levels, an order of magnitude more

wildfire than presently occurs would need to occur. Planned prescribed burns are very

constrained in area. For example, if only prescribed burns were occurring, the fire rotation would 

be 112 years. The limitations on the amount of area that can be burned by prescribed fire are 

often beyond the control of the park (e.g., air quality restrictions). In addition prescribed burns 

and are limited to mainly surface fire effects.

Assessment Confidence and Data Gaps

Medium. There are important limits to the data. Unfortunately, most existing data for

reconstructing fire regimes capture only a portion of the variability in a fire regime (Whitlock et 

al. 2010). There would be greater variation detected in fire frequency and behavior if we could 

assess a longer record. In addition, published fire rotations consider only small landscapes (Beaty 

and Taylor 2001; Bekker and Taylor 2001, 2010; Taylor 2000) and the time period used for 

assessing high severity fire was far shorter than the rotation for high severity fire.

Future amount of stand-initiating fire will be monitored under the land-use, land cover protocol 

of the Klamath Network Inventory and Monitoring program. Monitoring status and trends in the 

amounts of early successional vegetation is difficult with plot data because a large number of 

plots randomly located throughout the park would be required. There is no plot monitoring 

program in the park that accomplishes this.

4.3.4.3 Changes in Abundance of Major Vegetation Types

To evaluate how major vegetation types maybe shifting in abundance during the last 75 years 

due to successional processes, we performed a quantitative change detection study, comparing a 

historic (circa 1930s) vegetation map to a modern one. Figure 13 shows the 1930s Vegetation 

Type Map (VTM) vegetation map and the current map. The VTM map is not as spatially detailed 

as the current map. Neither map has had a quantitative accuracy assessment. The VTM maps are 

considered very accurate due to the extensive field work done to support them. The current map 

was done to the standards of the National Park Service Vegetation Mapping Program, and 

therefore is likely to be very accurate (>80%) as well.

Criteria

Good condition would be vegetation change is occurring, but which is not causing a net 

directional replacement of one vegetation type for another. In other words, processes like 

transition to late-successional vegetation are generally matched by transition to early 

successional vegetation, resulting in a steady state when the whole park landscape is considered. 

Somewhat Concerning and Significant Concern would represent increasingly greater amounts of 

directional vegetation change or “ecological drift.” 
55

Figure 13. The VTM map for Lassen (circa 1930) and the current vegetation map. Both have been 

crosswalked to a common cover type classification.
56

Condition and Trends

We provisionally assign a condition of Somewhat Concerning – Medium Certainty for the 

vegetation indicator. There have been substantial changes in some vegetation, as described below 

under trends. In particular, early successional vegetation has decreased markedly and it has been 

replaced by later-successional forests, with increasing dominance by species of fir. 

However, some of these changes may be slowed by an increase in fire with warming 

temperatures. In addition, the loss or early successional vegetation must be weighed against the 

gain of conifer vegetation, and especially the late successional stage of conifers. Although these 

changes are related to management, they have benefits for a number of species of concern that 

have declined regionally due to loss of late successional forests from logging (SNEP 1996). The 

late-successional forests at Lassen are important to regionally threatened species like spotted 

owl, fisher, and marten. 

Table 10 summarizes the vegetation transitions based on comparison of the VTM map and the 

current vegetation map. The first data column shows the historic vegetation and the second 

column the current extent of the same vegetation type. The rows provide the area of current 

vegetation into which the historic vegetation transitioned, while the columns provide the historic 

vegetation from which the current vegetation transitioned. The concordance between the areas 

mapped as lakes between the two time periods is an indication that the differences between the 

two time periods are minimally related to the difference in base maps used and the processing of 

the VTM map. There are a number of striking vegetation transitions that have occurred that are 

not explained by differences in vegetation classification between the maps. These transitions are 

highlighted in light green in Table 10; each is discussed below.
57

Table 10. Changes in area of broad vegetation types in Lassen Volcanic National Park, circa 1930 to present. Units are square km. Current

vegetation classes are based on the 2007 vegetation map prepared by James von Loh, but using the classification of Wildlife Habitats (WHR) from

the California Vegetation Map (Cal-Veg) prepared by the USDA Forest Service http://www.fs.fed.us/r5/rsl/projects/frdb/layers/ev_mid.html.

Historical vegetation is from the Wieslander Vegetation Type Map (VTM) surveys.

Analysis 3

Combined ADS and SCN. Plus combinations from Analysis 2. Changed Lupine and Wyethia mollis to Barren in vtm this version. O 

Current vegetation

Historic 

vegetation

Historic 

Km2

Current 

Km2 Aspen

BarrenBitterbrushJeffrey pineLakeLodgepole pineMontane chaparralMontane riparianPerennial grasslandRed firSubalpine coniferSagebrushUnknownUrbanWhite firWetland

Aspen 0.95 0.02 0.01 0.1 0.07 0.32 0.17 0.01 0.22 0.02 0.01 0.02

Barren 34.71 41.94 25.5 0.85 0.1 1.48 0.48 0.03 0.03 2.54 3.27 0.04 0.26 0.13

Bitterbrush 4.15 0.79 0.36 0.01 1.51 0.16 0.08 0.83 0.02 0.08 0.3 0.01

Jeffrey pine 101.83 26.25 1.66 20.3 0.43 10.67 2.42 0.25 0.45 39.00 1.06 0.01 25.3 0.3

Lake 8.34 8.44 0.33 0.15 6.54 0.51 0.01 0.03 0.63 0.12 0.02

Lodgepole 

pine 65.22 55.74 0.01 0.57 2.21 0.41 28.26 1.29 0.22 0.44 29.15 0.23 0.15 0.01 1.76 0.51

Montane 

chaparral 40.48 21.24 0.64 0.64 0.01 1.18 8.86 0.06 0.16 18.38 0.33 0.14 0.04 0.05 9.97 0.02

Montane 

riparian 0.89 1.81 0.02 0.02 0.08 0.09 0.01 0.34 0.32 0.01

Perennial 

grassland 3.45 1.45 1.11 0.02 0.41 0.04 0.19 0.05 0.9 0.14 0.12 0.47

Red fir 115.62 215.43 3.13 1.55 0.44 6.92 5.92 0.39 0.14 88.06 0.69 0.11 0.01 0.08 7.71 0.47

Subalpine 

conifer 57.38 19.95 7.39 0.09 1.82 1.7 0.13 0.1 30.66 13.83 0.01 0.05 1.21 0.39

Sagebrush 0.52

Unknown 0.33 0.05 0.06 0.04 0.1 0.1 0.03

Urban 0.24

White fir 5.34 47.53 0.15 0.05 1.19 0.29 0.04 0.05 3.02 0.03 0.51 0.01
58

Aspen. Note that the 0.95 km2 historical extent of aspen in the VTM map has been almost 

completely replaced by conifer forests in the modern map, primarily lodgepole pine and red fir 

(Table 10). Figure 14 shows the past occurrence of aspen and the few remnant stands that remain 

today. Most of the loss occurred on the east side of Snag Lake. Aspen are still common in this 

area, but conifers have become more common. There was also a lot of aspen loss in the Warner 

Valley in the Park’s southeast corner, although outside the park (not shown) there was a much 

greater loss. This entire valley used to have a large, continuous corridor of aspen. 
59

Figure 14. Historic distribution of aspen- (Populus tremuloides) dominated forests at Lassen as depicted in VTM mapping, and current distribution.

Arrows help point out the current distribution.
60

Jeffrey pine. This vegetation type declined from 101 km2 in the VTM map to 26 km2 in the 

modern one. Jeffrey pine transitioned to mainly red and white fir as well as to some lodgepole 

pine (Table 10). There has not necessarily been a significant loss of Jeffrey pines, but the 

dominance in many forests containing Jeffrey pine has now shifted to fir in the absence of fire. 

This shift may occur in as little as 30 years in the southern Cascades (Agee 1993), or about the 

average historic fire rotation. 

Mountain hemlock and whitebark pine. There has been a similar transition of most of the 

subalpine conifer woodlands to red fir forest (Table 10) which may also reflect an increase in red 

fir density rather than a loss of subalpine trees like mountain hemlock (Tsuga mertensiana) and 

whitebark pine (Pinus albicaulis). In fact, the abundance of mountain hemlock has been found to 

be increasing (Taylor 1995), but the cover may not be increasing as much relative to the cover of 

red fir.

Montane chaparral. This shrub type is only half as abundant in the modern map as the VTM 

map, with the bulk of the transition being from chaparral to red fir (Table 10). These afforested 

areas are now mostly open red fir with an understory of Arctostaphylos nevadensis. This is the 

most common vegetation type in the modern map. In the VTM map, these areas may have also 

contained some firs, but at a considerably lower density than they do today. Thus, this transition 

is not necessarily a case of wholesale change from treeless shrublands to shrubless treelands. 

However, such wholesale conversion has also probably occurred in some areas, particularly 

where dense white fir has displaced chaparral dominated by Arctostaphylos patula and 

Ceanothus velutinus.

Red fir and white fir forest. With the transition from Jeffrey pine, subalpine woodlands, and 

chaparral to red and white fir woodlands and forests, there has been a substantial increase in 

these fir forests (Table 10). This is shown in Figure 15. Much of the shift appears to be 

downward in elevation, reflecting the succession in areas previously dominated by Jeffrey pine 

and chaparral. While shrubs may have promoted this increase in red fir (see explanation in 

section 4.3.3.2 Vegetation succession above), it is also possible that it might be related to climate 

change. An analysis of FIA plots from the Pacific Northwest has found that forest trees are 

growing 5 to 23 percent faster, with those in upper montane zones being the most affected (Latta 

et al. 2010). This likely is partly attributable to lengthening of growing seasons due to climate 

warming, and partly to increased atmospheric carbon dioxide (Huang et al. 2007). The latter is 

supported by CO2-enhanced growth of ponderosa pine and western juniper (Knapp et al. 2001, 

Soulé and Knapp 2006). Longer growing season and increased atmospheric CO2 may thus 

expand the environment favorable to red fir. They would also promote growth of firs in 

subalpine woodlands, which is where increased growth rates of subalpine coniferous trees in 

recent decades was first described (Graumlich 1991).
61

Figure 15. Historic distribution of red and white fir (Abies magnifica and A. concolor) dominated forests at

Lassen as depicted in VTM mapping, and current distribution of forests dominated by these species.

Wetlands and riparian. There has been a considerable loss of wetland vegetation (5.5 to 3.6 

km2

). This transition has mainly been to lodgepole pine and red fir. Growth of these trees in 

meadows generally occurs around the meadow margin and has been described in studies from 

Lassen (Taylor 1990).

It is likely that current transitions caused by lack of fire will continue, although climate change is 

projected to increase rates of fire. This subject is discussed in the previous two sections and the 

discussion of issues. The occurrence of the Reading Fire helped restore the fire process. The fire 

was predominantly low in severity, but did restore some early successional habitat, and it 

reduced fir dominance in some areas. Future assessments are needed to ascertain the full effects 

of the Reading Fire. In contrast, prescribed burning is very limited in the amount of area that can

be treated, elevating the importance of wildfires in terms of restoration (Odion and Hanson 

2006).
62

Assessment Confidence and Data Gaps

Medium. Vegetation transitions have to be evaluated carefully to consider the possibility that

they are not caused by differences in the classification between the two maps. When this is done 

judiciously, it is possible to identify clear and consistent trend, but the magnitude of change 

estimated is not considered precise, and the error cannot be quantified. 

4.3.4.4 Invasive Plants

Criteria

Good condition would be a low amount of invasion by exotic species and Somewhat Concerning

and Significant Concern would represent increasingly greater problems with invasive exotic 

species.

Condition and Trends

With only very limited occurrences of invasive species and no areas of the park in which the 

vegetation structure, function, and composition have been transformed by invasive species, the 

condition with regard to this indicator may be considered Somewhat Concerning – Medium

Certainty. Current control efforts and other management practices are paying dividends, and lack 

of fire also benefits conditions related to this indicator.

Invasive species found so far in Lassen are listed in Appendix D. There are no comprehensive 

sources of information on the locations and extent of invasions by non-native plants at Lassen. 

There are records of where control efforts have been undertaken and there are records from fire 

monitoring (FMH) plots where fire treatments have been done. There are also monitoring 

surveys from the Klamath Network along a subset of roads and trails. None of these data were 

collected from a probability sample of the entire park, or even of areas necessarily at highest risk 

of invasives. There are, however, data covering non-native plants from probabilistic sampling 

done for the 2005 park-wide wetlands assessment as described in section 4.2.4.3 (Adamus and 

Bartlett 2008) as well as from one vegetation mapping project. Vegetation sampling for a second,

comparative vegetation mapping project used a relevé approach to subjectively locate plots 

across the range of variation in vegetation types. In concert, these three databases comprise 1050 

plots. 

In the combined database of 1050 plots, only 29 plots (3%) had a total of 52 infestations by 14 

species. Figure 16 shows the distribution of infestations and the locations of all plots sampled. 

This does not include the FMH plots or monitoring by the Klamath Network.
63

Figure 16. Locations of infestations and all sampling locations (n=1050) at Lassen from the two 

vegetation sampling databases and the wetlands assessment database. Green dots indicate plots with an 

invasive species. The smallest green dots indicate one invasive species present, while increasingly larger 

dots indicate 2, 3, and 4 invasives.

Most (34) of the 52 infestations in these vegetation sampling plots were in wetlands, which 

comprise only a small fraction of park area. The high apparent incidence could be due partly to 

the heightened intensity of sampling and thoroughness of taxonomic identification within the 

wetlands visited. Cover values for the invasives were less than one percent except in two 

infestations of Poa pratensis, one of Cirsium vulgare, and one of Taraxacum officinale, all from 

wetlands, where cover was 1-25% (most were at the low end of this range). The invasives in 

these plots are listed in Table 11. They tended to occur at the lowest park elevations, except for 

Spergularia rubra, which was found in an alpine plot. Of the invasives found in the 1050 plots, 

most are not ecosystem transformers, which are the primary concern with biological invasions 

(Davis et al. 2011). The exceptions are Bromus tectorum and Cirsium vulgare. Bromus is an 

ecosystem transformer in the Great Basin through its effects in causing more frequent surface 

fires and altering the nitrogen cycle in its favor. Cirsium can quickly invade and dominate 

disturbed areas like burns. Verbascum thapsus is also frequently considered a pernicious invader. 
64

It is a very conspicuous species and often invades open areas lacking other vegetation. But, 

strictly speaking, it may not be an ecosystem transformer.

Table 11. Species found in 1050 vegetation sampling plots from 2007-2010 in Lassen National Park.

Species Number of Plots Elevations (M)

Agrostis gigantea 4 2075-2206

Bromus inermis 2 1880-2026

Bromus tectorum 1 1861

Cirsium vulgare 6 17-851982

Festuca pratensis 1 1879

Phleum pratense 1 1656

Plantago major 1 1785

Poa annua 1 1785

Poa pratensis 12 1639-1982

Prunella vulgaris 1 1956

Spergularia rubra 1 2791

Taraxacum officinale 15 1879-1982

Tragopogon dubius 1 1880

Verbascum thapsus 6 1639-1918

The Klamath Network I&M program has implemented a protocol for early detection of invasive 

plant species. This protocol targets only the most invasive species, so there is no record of 

occurrence for most of the species. A total of 65.7 road and trail kilometers were sampled by the 

Network’s monitoring; three of the targeted species were detected in that sample. The species, by

descending abundance, included: musk thistle (Carduus nutans), bull thistle (Cirsium vulgare), 

and goat’s beard (Tragopogon dubius). Musk thistle is a very invasive species that had not been

previously detected according to National Park Service Database, and its identification needs to 

be confirmed. Figure 17 shows the locations of infestations found by the Network’s monitoring

in 2011.
65

Figure 17. Locations of invasive species found during the Klamath Network Monitoring in 2011. The 

green lines show the routes that were surveyed.

In general, the findings from vegetation sampling and invasives monitoring confirm qualitative 

assessments for the Park. Among the more invasive species, bull thistle (Cirsium vulgare) and

woolly mullein (Verbascum thapsus) are the two most widespread weeds in the park. 

Intermediate wheatgrass (Elytrigia intermedia ssp. intermedia) and smooth brome (Bromus

inermis) are found in the southwest corner of the park near the old ski slope. Yellow salsify

(Tragopogon dubium) is widely distributed but not abundant in disturbed areas. Other exotic

species such as dandelion (Taraxacum officinale) and self-heal (Prunella vulgaris) are found in

moist or disturbed areas of the park, but are not expected to transform ecosystems, nor are they 

currently targeted for treatment. Surveys in 2003 found a population of five Canada thistle

(Cirsium arvense), a potential ecosystem transformer, on the west shore of Snag Lake, but a

survey in 2005 and 2009 did not find this species there. Canada thistle is also found in the

sewage mounds area near the southwest park entrance. A stray Himalayan blackberry (Rubus

discolor) was found but not removed at Terminal Geyser. Reed canary grass (Phalaris

arundinacea) was reported at the Warner Valley horse corral in 2003 and a large infestation was 

found in Dersch Meadows in 2009. Park staff is treating Phalaris as an invasive exotic, because 

of its location (adjacent to existing or historic corrals) and its behavior (rapid spread, exclusion 

of other species). Cheatgrass (Bromus tectorum) was mapped in 2005 on the edge of Butte Lake.
66

It has since been documented from seven other sites throughout the park, including most recently 

in a severely burned area northeast of Lost Creek Campground (Janet Coles, pers. comm. 2012).

Of 74 burned fire monitoring (FMH) plots, 18 (24%) had infestations by four species. Thus, 

burned plots had a greater than tenfold higher incidence of infestation compared to the rest of the 

landscape (there were 20 infestations in almost 1000 non-wetland and unburned plots). This 

highlights a difficult tradeoff for park managers: fire and fire management activities tend to 

promote invasives, but fire needs to be re-established as an ecological process to restore

historical conditions. The most common invasive in burn plots was Cirsium vulgare, found in 12 

plots after burning. Its maximum cover was 4% in one montane chaparral burn at year 7, but it 

was subsequently absent at year 10. This may be because of intensive control efforts that 

removed all Cirsium from this burn area several years in a row. There were no pre-fire data 

available. All other plots had <1% cover of Cirsium. Poa pratensis was found in three forest 

plots prior to burning but not after. It was also found in three forest plots two years after fire and 

post-fire cover was 0.3%, 1.5%, and 2.4%. These plots have not been subsequently sampled. 

Two additional species not known to the park were also found: Antennaria umbrinella (one plant 

observed in one forest plot five years post-fire); and Hypochaeris radicata (observed as being 

present one year post-fire in two forest plots, but then was not observed in the year-two post-fire 

read). A possible explanation for such an unexpected disappearance is misidentification. It 

cannot be assumed that all species in FMH plots were correctly identified.

There are no specific data on invasive plant species’ trends in Lassen. In general, there are ever

increasing numbers of potential invaders. Climate change may increase the susceptibility of

higher elevations to invasive species. So will increasing fire and/or fire suppression efforts 

should these occur.

Assessment Confidence and Data Gaps

Medium. More remote areas of the park that are not traversed by trails are poorly sampled by 

most previous vegetation surveys. However, these areas are less likely to be invaded. There is a 

need for comprehensive monitoring of all invasives. The park staff has initiated (as of 2010) a 

systematic survey for invasives in the highest probability areas of the park (burned areas and 

developed areas past and present, and areas scheduled for prescribed burning and mechanical 

treatment). This system is derived from methodology developed by Steve Dewey and Kim 

Andersen at Utah State University (Janet Coles, pers. comm. 2012). It has been very successful 

at finding weeds in out-of-the way places and accurately defining the extent of infestations. 

Ideally, such a program should be designed to feed into rapid response control programs and 

adaptive management as shown in Figure 18, and this is the intent of the Lassen program. 

However, it remains to be determined how adequate it may be for determining long-term trends.
67

Figure 18. Conceptual model of an invasive species early detection program and the feedbacks with

management (From Odion et al. 2010a).

4.3.4.5 Invasive Pathogens

Criteria

Good condition would be a complete lack of blister rust and other exotic pathogens, or perhaps a 

very low amount and poor prospects for it to spread. Somewhat Concerning, would be a 

moderate amount of blister rust that would reduce whitebark pine populations, and Significant

Concern would be a greater amount, significantly reducing whitebark pine. 

Condition and Trends

Condition of this indicator is Significant Concern – Very Low Certainty. As summarized below,

previous information suggested that whitebark pine infection rates were very low. However, new 

information (Jules et al. 2012) suggests that they may be much higher. The existing sources of 

information are based on very limited (spatially) sampling. 

Whitebark pines are currently suffering severe impacts in many parts of their range. Where

Whitebark pine has been monitored in Lassen under a California state-wide program of the US 

Forest Service (Patricia Maloney, Research Associate UC-Davis, pers. comm. August 2006). The

USFS monitoring effort established 44 plots in the Sierra and Southern Cascades ranges. Four of 

these plots were in Lassen. A very low incidence of blister rust (~3% of trees) was reported from
68

those four plots. To the south of Lassen, blister rust has rarely been found in whitebark pine 

(McKinney et al. 2012) until a recent study by Maloney et al. in the Lake Tahoe area. They 

studied eight populations and found a mean incidence of blister rust of 35%. To the north, at 

Crater Lake, Smith et al. (2011) found about 25 percent of whitebark pine trees were infected 

with blister rust. More recently, Jules et al. (2012) found that in ten plots, on average, white pine 

blister rust had infected 69% of whitebark pine in Crater Lake and 53% in Lassen. 

Available data are insufficient to assess trends in blister rust or other plant pathogens within 

Lassen. Future monitoring by the Klamath Network should provide a much better assessment of 

current condition (McKinney et al. 2012).

Assessment Confidence and Data Gaps

Poor. Monitoring for blister rust has not been spatially or temporally intensive. Only a rough 

idea of present disease levels exists. However, it seems unlikely that blister rust would not affect 

the whitebark pine at Lassen to a similar degree as those at Crater Lake, which have been hit 

hard, or in the Lake Tahoe area, where the disease is also common.

4.3.4.6 Rare Plant Species and Species Diversity

Criteria

For purposes of this assessment, “Good” conditions would be represented by naturally-occurring

turnover rates of all native plant species currently inhabiting the park. This might include

intentionally re-establishing those which were extirpated but have the potential to become reestablished. More detailed goals might be to sustain multiple representatives of each functional 

group of plants in proportions characteristic of intact but dynamic ecosystems, as well as 

sustaining metapopulations and gene pool diversity. “Somewhat Concerning” and “Signficant 

Concern” would represent increasingly high turnover rates of all native plant species currently 

inhabiting the monument.

Condition

Although there are no federally listed plant species within the park, Lassen hosts at least 23 plant

species that are termed “special status” by the California Native Plant Society. Almost all are

found either in wetlands or in the high elevation subalpine zone. Two bryophytes with arcticalpine distributions (Andreaea nivalis and Polytrichum sexangulare) reach the southern extreme 

of their range in late snow melt beds at Lassen (Showers 1982), and would thus be expected to 

be highly vulnerable to a warming climate. 

The Klamath Network Inventory and Monitoring program, like many other network I&M 

programs, analyzed the potential for using rare species as vital signs (reviewed in Sarr et al. 

2007). Analyses of statistical power and other issues have shown that rare plants are impractical 

to use as ecological indicators (Manley et al. 2004). Thus, the policy of the Klamath Network has 

been to avoid focusing on just rare species and instead to sample all vegetation. Diversity 

patterns within vegetation (composition) are a key component of this vital sign.

Trends

Trends in Lassen’s plant species diversity and rare species in particular are Indeterminate. 

Populations of three rare plant species on the summit of Lassen Peak have been monitored
69

regularly with transects since 1997, but data are probably insufficient to determine any trends. 

Sampling for the ongoing vegetation mapping project, as well as the 2005 wetlands survey, 

documented several new taxa for the park. Whether there are species that have been extirpated is 

impossible to say, partly because the exact locations of many historically-reported species were 

not described, at least not with the precision currently available with GPS. There is no particular 

reason to assume that any of these species has been extirpated from the park.

Assessment Confidence and Data Gaps

Low. Although the park’s flora has been relatively well inventoried, no permanent plots or 

transects representing a probabilistic sample of plant communities in the park have been 

monitored. Only a few locations known to support rare plants are checked regularly to determine 

if those individuals are extant. 

4.4 Changes in Wildlife

4.4.1 Background

As used herein, “wildlife” refers to terrestrial vertebrates and invertebrates. The opportunity to 

observe wildlife in natural settings is an important reason why many people visit parks. 

Moreover, wildlife species serve vital ecological roles, such as pollinators, nutrient cyclers, and 

seed transporters.

4.4.2 Regional Context

For its size, the park has a particularly rich array of plant and animal species. This is partly due 

to the great range in elevation with associated diversity of climates, and partly due to the park’s 

position at the crossroads of four major bioregions—the Cascades to the north, the Central 

Valley to the west, the Sierra Nevada to the south, and the Great Basin to the east. In addition, 

the diversity of both new and old geological phenomena, combined with occasional wildfires and 

some human influences, have created a particularly rich flora and fauna. 

4.4.3 Issues Description

4.4.3.1 Fire Suppression and Natural Succession

The volcanic blast in 1915 removed all vegetation in parts of the park. In areas that were

relatively unaffected, decades of wildland fire suppression have affected the types of habitat

available to wildlife. Undoubtedly some species have benefitted from the shrinkage of shrub

habitat and open meadows where succession to conifer forest has occurred, whereas others—

such as snowshoe hare, Cascades frog, and fox sparrow—may have found the new conditions

less hospitable. Fire suppression also can result in fewer snags, which are necessary for some

bats, woodpeckers, and other wildlife. Prescribed burns and thinning for the purpose of reducing

understory fuels may affect some species as well, at least based on evidence from other regions 

of the United States (Pilliod et al. 2003). Fuel treatments are sometimes accompanied by indirect 

loss of woody debris, litter, and shade, as well as changes in stream bed substrates and stream 

characteristics such as flow, temperature, and sedimentation. However, fuel build up may 

ultimately lead to unnaturally severe fires that result in loss of habitat, also resulting in increased 

stream and air temperatures, and in increased sedimentation in streams.
70

4.4.3.2 Climate Change, Water, and Snow Pack

Boreal species whose geographic range is predominantly in states and provinces north of

California are expected to decline the most—and possibly be lost entirely from the park—as a

result of warming climate. This includes all the characteristically subalpine plant and animal

species. Because the park’s wetlands, streams, and ponds are so dependent on snowmelt, many

fish, amphibians, and other organisms that live in or feed over water could suffer as well. An

analysis of the vulnerabilities of California nesting birds to climate change was published by

Gardali et al. (2012). Of 128 species they identified as most vulnerable, the terrestrial species 

that are likely to have formerly or currently nested in the park include sooty (blue) grouse, 

northern saw-whet owl, common nighthawk, common poorwill, Vaux’s swift, black-backed 

woodpecker, pileated woodpecker, gray jay, Swainson’s thrush, Brewer’s sparrow, fox sparrow, 

and red crossbill.

4.4.3.3 Contaminants

Effects of contaminants on the park’s terrestrial species have not been monitored, but are a

potential concern because of well-documented aerial transport of contaminants into the park

from distant areas. Bats, swallows, and other aerial foragers are likely to be at greatest risk.

4.4.3.4 Human Disturbance

Some wildlife species, including many avian nest predators (raven, Steller’s jay) are attracted to

congregations of people such as at campgrounds and picnic areas, with potentially detrimental

effects on many songbird species. Other species, such as badger, appear to partially avoid

human-inhabited areas.

4.4.3.5 Habitat Fragmentation

When the home ranges of some forest-dwelling species are interrupted by roads and other

cleared areas, undesired results are termed habitat fragmentation. Individuals are often subjected

to greater predation, and feeding and reproductive attributes (e.g., genetic isolation) also can be

interrupted. Roads and traffic result in more road killed animals, and in extreme cases, noise

associated with roads impairs reproductive success of some wildlife. To some degree, wildlife

corridors (usually, unaltered bands of natural vegetation that connect larger patches and so create

“connectivity”) can lessen fragmentation impacts on wildlife, as can management practices

within the cleared areas that leave relicts of the original vegetation structure. Connectivity and

fragmentation are perceived differently by different species. Functional connectivity of habitat

for one species (e.g., deer, cougar) is not necessarily recognized by other species (salamanders,

plants). Connectivity can also be provided by some types of broad habitat mosaics over large,

relatively natural areas or as stepping stones of habitat patches.

4.4.4 Indicators and Criteria to Evaluate Condition and Trends

Two indicators that might be used to monitor this issue (Changes in Wildlife) are:

1. Presence and Persistence of Native Terrestrial Wildlife Species

2. Connectivity and Extent of Important Terrestrial Habitats
71

4.4.4.1 Presence and Persistence of Native Terrestrial Wildlife Species

At least 280 native vertebrate species are believed (or have been confirmed) to regularly visit or

breed in the park. Analyses by the California Department of Fish and Wildlife (2013a) using 

coarse land cover characteristics (circa 2000) and geographic range information predicts where 

species are likely to occur throughout the state. Their analysis suggests that for birds, the rarityweighted richness would be expected to be highest within the park around Snag Lake and also 

near the Warner Valley. For mammals the analysis suggests the highest expected richness, 

weighted by species rarity, is near the southwest entrance and also near Warner Valley. For 

amphibians the highest expected richness, weighted by species rarity, is mostly in the southern 

half of the park and also near Manzanita Lake. For rarity-weighted plant richness, the entire 

western half of the park is expected to be more significant.

Criteria 

Local and regional data on native terrestrial wildlife species are insufficient to quantify reference

conditions for this park, so qualitative statements will define the reference conditions. “Good”

conditions would be represented by the sustaining of naturally-occurring turnover rates of all

native terrestrial species currently inhabiting a park. This might include intentionally reestablishing those species which were extirpated but have the potential to become re-established.

More detailed goals would be to sustain multiple representatives of each functional group in

proportions characteristic of intact but dynamic ecosystems and well-functioning complex food

webs, as well as sustaining metapopulations and gene pool diversity. “Somewhat Concerning”

and “Significant Concern” ratings would reflect the degree to which species turnover rates and/or

terrestrial biodiversity are likely to affect adversely the rates of important ecosystem functions.

In national forests of the Sierra Nevada region, the USDA Forest Service (2008) has chosen and 

is monitoring the following terrestrial vertebrates and their associated habitats as “management 

indicator species”: 

fox sparrow – west slope chaparral shrubland

mountain quail – early and mid-seral coniferous

sooty grouse – late seral open canopy coniferous

spotted owl, American marten, northern flying squirrel – late seral closed canopy 

coniferous

hairy woodpecker – snags in unburned forest

black-backed woodpecker – snags in burned forest 

Meaningful criteria for evaluating these indicators would need to account for the natural range of

variation in species colonization and extirpation, and for the expected annual fluctuations in

population levels. However, data for estimating these are not generally available from the park or

from analogous areas nearby. As well, there are no legally-sanctioned numeric criteria for

evaluating the degree of “intactness” of any of the park’s terrestrial communities. No agency,

institution, or scientific researcher has defined minimum viable population levels, desired

productivity or species richness levels, or other biological criteria relevant to any wildlife species

in this particular park. Therefore, the assessment of this indicator is based mainly on professional

judgment of the authors.
72

Condition 

Good – Low Certainty. Compared with the rest of California, large sections of the park fall 

within the highest of six categories for rarity-weighted richness of birds, mammals, and plants, 

and the next-to-highest category for rarity-weighted richness of amphibians (CDFW 2013a).

Among non-native mammals, there are apparently no records from the park of house mouse,

non-native rat species, feral cats, or feral pigs. Virginia opossum (Didelphis virginiana) was

introduced to California from the eastern United States about a century ago and there is an old 

record from the Manzanita Lake area of the park. Of the more than 200 bird species recorded in 

the park, none which nest in the park are non-native in this region. Two other birds not native to 

the area—house sparrow and barred owl—have been recorded just outside the park boundary. 

Although they are native, brown-headed cowbirds are regularly found at lower elevations, have 

increased in numbers in the last 75 years, and parasitize the nests of many songbirds (Borgmann 

& Morrison 2010). Their numbers are declining in the Sierras and possibly in the park as well 

(Sauer et al. 2011). Of the park’s seven documented amphibians, only one (American bullfrog,

Rana catesbiana) is non-native; none of the reptiles are non-native.

Ungulates, Omnivores, and Predatory Mammals. The park’s most common ungulate is mule

deer (Odocoileus hemionus columbianus). In summer, one of the largest deer herds in California

is present in the park; this herd migrates nearly 20-50 miles to lower elevations in winter. Elk

(wapiti) have been reported on a few occasions. Attempts were made in the 1970s to introduce

mountain bighorn sheep (Ovis canadensis), but those attempts failed due to a disease outbreak.

The park’s larger omnivores include black bear, raccoon, and possibly ringtail. Black bears are

relatively common. The park is outstanding for its relatively high number of predatory mammals

which include: mountain lion; bobcat; badger; coyote; gray fox; red fox; and six mustellids—

mink, ermine, long-tailed weasel, marten, and river otter.

Lassen is one of only a few places in the world where a native subspecies of the red fox, the

Sierra Nevada red fox (Vulpes vulpes necator), is found. Its presence has also been confirmed at

Yosemite National Park and in the Humboldt-Toiyabe and Stanislaus National Forests. The

species is listed as Threatened under the California Endangered Species Act, and the population 

is believed to be relatively small. As summarized by Perrine et al. (2010), most records are from 

elevations of between 1500 m and 2100 m in the Sierra Nevada and southern Cascade Ranges. 

Greatest densities appear to occur near Lassen Peak, and they are primarily forest-dwellers 

(Grinnell et al. 1937, Schempf and White 1977). In winter, they use forests with large trees (>60 

cm diameter) and >40% canopy closure. Summer home range size is about 2300 hectares. 

Concern has been expressed about the potential for increased mortality from disease and reduced 

genetic adaptation to local conditions if interbreeding with non-native red foxes occurs, as those 

appear to be expanding into high elevation areas that overlap. Although seeming to usually 

prefer areas relatively remote from humans, Sierra Nevada red foxes occasionally linger near 

human residences and roads where they may find food and denning sites, and where competition 

with coyotes is sometimes lessened (Gosselink et al. 2003, Perrine 2006).

Another native predatory mammal is American (or pine) marten. The park and surrounding

national forest may provide some of the most extensive suitable habitat for this species in

northern California (Figure 19). Suitable habitat consists of large patches of higher-elevation

forest with large diameter (>11 inch dbh) red fir, white fir, or riparian and subalpine conifers
73

with a moderate to dense canopy (Perrine 2006, Green 2006, Kirk and Zielinski 2009). 

Wintering martens do not appear to avoid or leave areas with limited presence of off-highway 

vehicles and over-snow vehicles (Zielinski et al. 2008). Populations of the closely related Pacific 

fisher (Martes pennanti pacifica) are much less in the region surrounding the park, and it may 

not occur at all within the park. If it does, it would be expected to inhabit a lower average

elevation than marten.

Figure 19. Predicted habitat suitability for American marten in the vicinity of the park (from Zielinski et al. 

2005).

Other Mammals. The park’s riparian areas have been found to support a greater diversity of 

mammals than higher elevation forests and subalpine habitat (Perrine 2006). American pika 

(Ochotona princeps) is a rabbit-relative that is believed to be disappearing in many areas of the 

West (Beever et al. 2003). Normally a mountain-dweller, the species is also found regularly in 

barren lava landscapes (Rodhouse et al. 2010) such as one photographed in a lava field near

Butte Lake (Paul Adamus and Cheryl Bartlett, 11 July 2005) which was also detected by Perrine 

& Conroy (2007). Other recent sightings are (for example) from the subalpine zone of Brokeoff 
74

Mountain (Perrine 2006) and near King’s Creek Falls (Perrine & Conroy 2007). Monitoring is 

ongoing as part of the NPS “Pikas in Peril” project.

Sierra Nevada snowshoe hare (Lepus americanus tahoensis) is a California Species of Concern

that is found sporadically in the park’s brush thickets. Inyo shrew (Sorex tenellus) is also rare,

and the park is one of only a few localities outside of the Sierra Nevada where it has been found.

Both that shrew and Preble’s shrew (Sorex preblei) were added to the park list in the last decade 

by a concerted NPS-sponsored Small Vertebrate Inventory Project (Shohfi et al. 2006, Perrine 

2006). Botta's Pocket Gopher (Thomomys bottae) is projected to occur in the park by CDFW 

(2013a) but the mammal survey documented only the closely related Thomomys monticola.

Other small mammal species projected to occur but for which no recent records exist include

Belding’s ground squirrel (Spermophilus beldingi), western harvest mouse (Reithrodontomys

megalotus), black-tailed jackrabbit (Lepus californicus), house mouse (Mus musculus), mountain

cottontail (Sylvilagus nuttallii), striped skunk (Mephitis mephitis), and western spotted skunk

(Spilogale gracilis). It is not possible to tell if they are currently present, were ever present,

and/or if survey methods used so far have not been optimal for their detection. While not rare in

the park, long-eared chipmunk (Tamias quadrimaculatus) is notable because it occurs only in the

Sierra Nevada ecoregion.

Eight species of bats were documented in the park in a 2001-2003 survey (Morrell 2002), with 

the long-eared myotis (Myotis evotis) being captured most frequently. None of the park’s known 

bat species are particularly rare in California, but bats in general are a concern due to low 

resilience to many environmental disturbances, which is partly because of their low reproductive 

potential. 

Birds. The park’s bird diversity has been relatively well-surveyed, notably in 1999-2000, by 

Humple (2001) and by a Breeding Bird Survey route (Chaos Crater, #308). The latter is part of 

the national network of Breeding Bird Survey routes. As part of that, birds have been surveyed

annually since 1977 by the park’s wildlife biologist along a 25-mile roadside route through the 

park (Table 12). Over 200 bird species have now been documented in the park one or more

times, and about half have nested. Nesting species that are the most common and widespread

within the park are mountain chickadee, dark-eyed (Oregon) junco, and yellow-rumped

(Audubon’s) warbler (Humple 2001).

Two pairs of the California spotted owl (Strix occidentalis caurina) have bred in the park most 

years, with one pair near Crags Campground and one in the Terminal Geyser area (Blakesley and 

Noon 1999). The California Endangered Species Act lists the willow flycatcher (Empidonax

traillii brewsteri) as Endangered. This species may nest in the park; Warner Valley meadow, 

nearby and south of the park, is believed to support one of the most significant breeding

populations in California (King et al. 2001), and historically this species might also have bred in

Sulfur Creek Meadows and around Snag Lake. Bald eagle and peregrine falcon have both been 

delisted from the federal endangered species list. The bald eagle is still listed as endangered by 

the State of California. There is one bald eagle nest and one peregrine falcon aerie in the park, 

and these are monitored annually.

The California DFG has designated four nesting birds in the park as statewide Species of

Concern: northern goshawk, Vaux’s swift, olive-sided flycatcher, and yellow warbler. They are
75

all fairly common to uncommon in the park. Also, the US Fish and Wildlife Service has

designated as Birds of Conservation Concern the white-headed woodpecker (a fairly common

resident) and rufous hummingbird (a non-breeding visitor). Species that are particularly rare

breeders in the park, but which are more common in parts of California with more suitable

habitat, include eared grebe, ring-necked duck, golden eagle, prairie falcon, common poorwill, 

western bluebird, Brewer’s sparrow, black-headed grosbeak, and gray-crowned rosy finch 

(Humple 2001, Burnett & King 2004).

Reptiles.No comprehensive surveys have been conducted of the park’s reptiles. Eighteen species

have either been documented or could potentially occur in the park (Appendix D). 

Terrestrial Invertebrates. Approximately 83 species of butterflies and 147 species of moths

have been recorded in the park, and a guide to those is available (Crabtree 1998). No park-wide

inventories of other invertebrates have been conducted. Two uncommon species—Edith's

checkerspot (Euphydryas editha) and Sheridan's hairstreak (Callophrys sheridanii)—have been

reported from the Lassen Peak area. In 2007 an annual parkwide butterfly count was initiated and 

is being conducted by the North American Butterfly Association and park staff. This may be 

useful in tracking changes in montane meadow conditions.

Special Habitats. Non-living areas with very different physical structure, such as rocky outcrop

areas, talus slopes, cliffs, and lava flows provide habitat for very specialized animal species

and/or species with limited regional distribution. In this park, cliff faces are likely to be

important to some roosting bats and nesting swallows. Talus and volcanic deposits, which are

regionally rare, are important to pika, yellow-bellied marmot, and bushy-tailed woodrat. Among

types of vegetation, aspen is renowned for its ability to support a particularly wide array of birds

and mammals (see section 4.3.4.6). Large snags of all tree species are required by many bird

species and are important roosting sites for bats. Data on the size and age of snags in parts of the

park have been collected from five permanent plots since 1988. Snags are most common in

lightly-burned areas and where trees have recently been killed by insects, disease, or beaver.

Their importance to the park’s woodpecker species was documented by Farris et al. (2004) and 

Farris & Zack (2008). Of 23 habitat types surveyed in the park, burned areas were found to have 

the most diverse assemblages of breeding birds, owing at least partly to their abundant snags 

(Humple 2001).

Trends

Indeterminate. No Lassen data spanning more than a decade have been collected to determine 

changes in abundance of any species, except for birds. Within the park, there is no definitive

evidence so far of changes in any species distribution that can be attributed to long-term climate

change. However, the park has begun participating in the National Phenology Network (NPN)

and California Phenology Project (CPP) whose aims are to measure changes in the timing of

seasonal or periodic biological events such as flowering, leaf-out, insect emergence, and animal

migration. Populations of eight plants are being monitored: quaking aspen, lodgepole pine,

ponderosa pine, greenleaf manzanita, blue elderberry, mountain pride (Penstemon newberryi),

satin lupine (Lupinus obtusilobus), and woolly mule’s ears (Wyethia mollis). Monitoring sites are

at Loomis Museum, Manzanita Air Quality Station, Emigrant Trail, Sunflower Flats, Manzanita

Lake, Hot Rock, and Devastated Area. For the Northern Hemisphere as a whole, in the past

century the number of species of birds, butterflies, and alpine herbs has shown an average shift
76

of 6.1 km per decade northward (or 6.1 m per decade higher in elevation), and a mean shift

toward earlier onset of spring events (frog breeding, bird nesting, first flowering, tree budburst,

and arrival of migrant butterflies and birds) of 2.3 days per decade (Parmesan and Yohe 2003).

While the park maintains a wildlife observations database, those data are not systematic so no

inferences can yet be made about relative abundance or shifts in elevational or geographic ranges

or species productivity.

Mammals. Gray wolf, grizzly bear, and wolverine are believed to have occurred in the park

historically but with high certainty are no longer present. Wolverine was thought to have been

extirpated from California around 1922, but a single individual was confirmed in Tahoe National

Forest in 2010. Except for a lone straggler in early 2012, the last wolf reliably documented in

California was trapped in Lassen County in 1924. The disappearance from the park of river otter 

and ringtail, implied by Newmark (1995), is untrue. It remains uncertain whether Nuttall’s 

cottontail, Pacific fisher, striped skunk, and pronghorn have been permanently extirpated from 

the park, as implied by Newmark (1995).

During the late 1950s and early 1960s, the deer herd bordering the park in Tehama County

numbered over 100,000, but drought in the 1980s caused a decline. As of 2001 numbers were

down to about 22,000. The herd may now be limited by lack of sufficient openland with its

associated food plants; that insufficient openland is the result of fire suppression and land use

changes.

Trends in populations of the Sierra Nevada red fox within the park are uncertain, but statewide

this species was believed to be declining (Schempf and White 1977). Perrine (2006) suspected 

that the park’s population might be under stress, as evidenced by abundance of low-palatability

foods in their stomachs (insects, shrews), below-average body size, large home ranges, and their 

regular “begging” at campsites and parking areas. Zielinski (2004) and Zielinski et al. (2005) 

suspected that populations of American marten may now be less well distributed in the area

around Lassen than they were in the early 1900s, but evidence is not definitive.

Bat populations in many areas of the U.S. are believed to be declining, but data from California

and this park are insufficient to determine if this is true here. Likewise, trends in population or

distribution of pika within the park are unknown. In a broad geographic area that included the 

park, Massing (2012) resurveyed pika sites reported by Grinnell in the 1930s as part of the

historical Lassen transect, plus some additional sites. Eleven of 17 (65%) of the historical pika

sites were occupied; 6 of 17 (35%) additional surveyed sites were occupied.

Birds. Our analysis of data from the annual Breeding Bird Survey route through the park, 1972 

to 2009, shows statistically significant increases in the number of species (Figure 20) but a 

decrease in the individual birds detected (Figure 21). Nine species show a statistically significant 

increase while eleven show a statistically significant decrease. For the most part, trends in the 

park mirror those in the Sierra Region as a whole, as reported by the BBS for the period 1977-

2007. However, the in-park decrease in green-tailed towhee and common nighthawk, and the inpark increase in warbling vireo, is counter to the regional trend and suggests in-park factors (e.g., 

vegetative succession, weather on survey days) might have influenced the estimates for these 

species. Green-tailed towhee is associated with manzanita vegetation, whose extent in the park 
77

may be less than half what it was 70 years ago. Common nighthawk nests in open lodgepole and 

grassy areas, which also have likely decreased in the park as vegetation became re-established 

following the eruption of Mount Lassen.

Figure 20. Number of bird species found on the annual Breeding Bird Survey route through the park, 

1972-2009. The curved line is the locally weighted regression line (with 40% smoothing). The straight line 

is the least squares regression with confidence bands. R2

=0.164, p=0. 0175, slope= 0. 1445, n= 34. Only 

the data primarily from the park (i.e., stops 1-30) were analyzed.

Figure 21. Number of individual birds found on the annual Breeding Bird Survey route through the park,

1972-2009. The model is: R2

=0.1458, p=0.0259, slope=-1.7936, n=34.

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Number of Species

160

180

200

220

240

260

280

300

320

340

360

380

400

420

1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Number of Individuals
78

Table 12. Species with statistically significant increase or decrease on the annual Breeding Bird Survey

Route through the park, 1972-2009. Only the data primarily from the park (i.e., stops 1-30) were

analyzed. “B” is the slope of the least-squares regression line, “R2”

is the coefficient of determination 

(goodness of fit), “p” is the significance level (<0.05 was considered statistically significant).

Common Name Route Trend

Sierra 

Trend, 1977-

2007

% of yrs 

Found on 

Route B R2 p

Purple Finch decrease decrease 26% -0.4747 0.3454 0.0003

Western Wood-Pewee decrease decrease 100% -0.4214 0.4394 0.0000

Steller's Jay decrease decrease 100% -0.3173 0.2513 0.0025

Dark-eyed Junco decrease decrease 100% -0.2800 0.1256 0.0398

Olive-sided Flycatcher decrease decrease 91% -0.1904 0.1658 0.0168

White-breasted Nuthatch decrease 26% -0.1707 0.2634 0.0019

Northern Flicker decrease decrease 85% -0.1460 0.2903 0.0010

Green-tailed Towhee decrease increase 24% -0.1382 0.3095 0.0006

Common Nighthawk decrease increase 50% -0.0510 0.2400 0.0033

Mountain Quail decrease decrease 50% -0.0482 0.1347 0.0327

Pacific-slope Flycatcher decrease 18% -0.0402 0.1704 0.0152

Spotted Sandpiper increase 9% 0.0095 0.1457 0.0259

Song Sparrow increase increase 26% 0.0242 0.1287 0.0372

Common Raven increase 35% 0.0423 0.3524 0.0002

White-headed Woodpecker increase increase 62% 0.0445 0.1166 0.0481

Lincoln's Sparrow increase 29% 0.0483 0.5627 0.0000

Canada Goose increase increase 15% 0.0730 0.1371 0.0311

Dusky Flycatcher increase increase 59% 0.1118 0.1920 0.0096

Warbling Vireo increase decrease 74% 0.2044 0.3362 0.0003

Yellow-rumped Warbler increase increase 100% 0.6358 0.4334 0.0000

At least three native species that are known to have nested in the park historically have not been

documented nesting for at least a decade: great gray owl (uncertain if ever nested in the park), 

ruby-crowned kinglet, and Swainson’s thrush. The Lassen transect surveyed by Grinnell in the 

1930s was resurveyed for birds in 2006 (Tingley 2007). Grinnell et al (1930). had found rubycrowned kinglet (a boreal species) during the nesting season at six locations above 4800 feet 

elevation, but neither Tingley (2007) nor others have found it nesting during recent decades. 

Swainson’s thrush has nearly been extirpated from the Sierras. The geographic ranges of all 

seven of these species are boreal, suggesting the possibility that warming climate might be an 
79

influence. In addition, four gamebird species—ruffed grouse, wild turkey, ring-necked pheasant, 

and common peafowl—appear to have been introduced in or near the park but there are no recent 

sightings from within the park. One species not reported in the park by Grinnell et al. (1930) but 

found since at least 1981 is gray jay.

Assessment Confidence and Data Gaps

Status of the park’s birds and amphibians is generally well known. Less is known about 

mammals, reptiles, and invertebrates. Some trend information is available for breeding birds, but 

reliable information on long term trends is lacking for nearly all species.

4.4.4.2 Connectivity and Extent of Important Terrestrial Habitats

What constitutes “habitat fragmentation” depends on the species and the structural characteristics

of the land uses that are purported to do the fragmenting. When assessing fragmentation,

conservation biologists often consider first the needs of species that have the largest home 

ranges. Some (e.g., Harrison 1992) have proposed that the width of a typical home range of the 

focal species be considered the minimum for assessing the sufficiency of a habitat corridor’s 

width. For example, gaps in the forest that are wider than 80 m might restrict the long-distance 

movements of marten (Heinemeyer 2002).

Criteria

For purposes of this assessment, “Good” conditions would be represented by unbroken

connectivity of natural vegetation on all sides of the park. At a landscape scale, another goal

might be to sustain corridors or stepping-stones of relatively unaltered habitat, especially along

elevational gradients, so as to facilitate upward “migration” of plants and species with limited

mobility in response to global warming. “Somewhat Concerning” would represent a measurable

loss of corridors of habitat suitable for locally rare or sensitive wildlife species as a result of

temporary setbacks of succession (e.g., fires, clearcuts), and/or declining populations of

threatened species known to be area-sensitive. “Significant Concern” conditions would represent

widespread and irreversible losses of those corridors as a result of roads, buildings, and other

newly unvegetated surfaces. The reference condition is imagined to be the landscape within and

around the park as it may have existed in the early 1800s, prior to settlement and prior to the

volcanic eruptions of the early 1900s.

Condition

Good – Medium Certainty. With regard to habitat fragmentation, the park is surrounded mainly

by other forested public lands and so has much better habitat connectivity than comparable-sized

areas in many parts of California. This fact is recognized by maps prepared by CDFW (2013b), 

which show the park as a hub with radiating spokes (corridors) to other natural lands in the 

region (Figure 22). Nonetheless, clearcut logging and road construction in the adjacent public 

lands could make species like California spotted owl more vulnerable to interbreeding with 

barred owl (which inhabits more open-canopied forests), and could increase the numbers of nest 

predators such as ravens. Commenting on one species, American marten, Rustigian-Romsos &

Spencer (2010) recommended:

“The large area of suitable and occupied marten habitat centered on Mount Lassen should

be better connected to the smaller occupied polygons elsewhere in the study area via

habitat that is suitable, at least during winter, for marten occupancy or dispersal. The
80

following general areas should be considered for vegetation management actions to

increase winter habitat quality and connectivity between the Mount Lassen polygon and

other winter occupancy areas:

— Higher-elevation areas lying between Mount Lassen and the Thousand Lakes

Wilderness to the north, including in and around Ashpan Butte, Huckleberry Mountain,

and Bear Wallow Butte.

— Higher-elevation areas between Mount Lassen and Butte Mountain to the south,

including the ridges on either side of Mill Creek (i.e., in and near Doe Mountain, Morgan

Hill, and Wild Cattle Mountain).

Kirk and Zielinski (2009) also recommended that east-west corridors from Lassen Volcanic

National Park to the Swain Mountain Experimental Forest should be studied with regard to their

likely importance to marten movements.

At one time at least one-third of the park boundary had been fenced to exclude livestock, but 

fences also have the potential to interfere with movements of deer. Most of this fencing has

fallen into disrepair, allowing most animals (including alien cattle) to move freely in and out of

the park.

Figure 22. Essential Connectivity Areas as mapped by CDFW (2013b) in the vicinity of the park.
81

Trends

Good – Low Certainty. Using the NPScape mapping tool14, we compared coarse-resolution land 

cover within 30 km of the park in 2001 to the same within that area in 1992. Conversions of 

natural land to agriculture or urban (or vice versa) were so limited that they are barely visible on 

the conversion map. The closest conversions of any extent were more than 10 km away. It is 

possible some habitat corridors not visible at this scale might have been severed over time, while 

others might have become more suitable for animal passage.

Assessment Confidence and Data Gaps

Medium. For the landscape surrounding the park, maps exist that show terrestrial land cover;

their evaluations of connectivity are based mostly on sound principles of conservation biology. 

However, they do not consider needs of individual species and may not have fine enough 

resolution to portray suitability for movements of some species.

4.5 Changes in Air Quality 

4.5.1 Background

Air quality is of interest aesthetically, and for ecological and health reasons. Ozone, particulates 

and wet and dry atmospheric deposition are monitored at Lassen because of their potentially 

harmful effects on park resources and visitors. Special studies at the park have also monitored 

toxic airborne contaminants.

4.5.2 Regional Conditions

The park is a Class I airshed, which is given the highest level of protection under the Clean Air 

Act. Although many parts of California are notorious for detrimental levels of air pollution, this 

has not usually been a significant concern in the northern Sierras and southern Cascades, except 

during major wildland fires.

4.5.3 Issues Description

Soils and vegetation in the park are, like lakes, sensitive to nutrient enrichment from nitrogen (N) 

deposition. In some parts of the nation, including areas in California, nitrogen deposition has

altered soil nutrient cycling and vegetation species composition. In some cases, native plants that

evolved under nitrogen-poor conditions have been replaced by invasive species that are able to

take advantage of increased nitrogen levels. Even in the absence of invasive species, nitrogen 

deposition can cause shifts in the species assemblages of native plants, especially lichens and 

mosses which largely obtain their nitrogen directly from atmospheric sources (Geiser & Neitlich 

2003, Jovan & McCune 2006). Because most of Lassen is higher than the surrounding terrain 

outside the park, the park likely receives relatively little runoff-borne nitrate, which typically is a 

major source of N to plants in human-altered landscapes. This suggests that the park’s plants 

might be ones that are particularly sensitive to atmospheric deposition of N. 

Levels of sulfate, ozone, and other contaminants are also potential concerns. Atmospheric sulfur

(S), mainly in the form of deposited sulfate, can acidify surface water and soils. Ozone, in the 

lower atmosphere, is an air pollutant, forming when nitrogen oxides from vehicles, power plants, 

 

14 http://science.nature.nps.gov/im/monitor/npscape/
82

and other sources combine with volatile organic compounds from gasoline, solvents, and 

vegetation in the presence of sunlight. In addition to causing respiratory problems in people, 

ozone can injure plants. Ozone enters leaves through pores (stomata), where it can kill plant 

tissues, causing visible injury, or reduce photosynthesis, growth, and reproduction. In the upper 

atmosphere, ozone absorbs the sun’s harmful ultraviolet rays and helps to protect all life on 

earth.

4.5.4 Indicators and Criteria to Evaluate Condition and Trends

Two indicators used to monitor the effects of air pollution on park resources and people are: 1) 

atmospheric deposition of nitrogen, sulfur, and contaminants; and 2) ambient ozone.

4.5.4.1 Atmospheric Nitrogen Deposition

Criteria

Some aquatic ecosystems respond to wet nitrogen deposition rates of 1.5 kg per hectare per year,

whereas there is no evidence of ecosystem harm at deposition rates less than 1 kg per hectare per 

year (Fenn et al. 2003a). A study of algae (diatoms) in other parts of the eastern Sierras 

determined that 1.4 kg N per ha per year (wet N deposition) was a threshold above which a shift 

in diatom community structure is commonly detected (Saros et al. 2011). The NPS Air 

Resources Division has suggested that wet nitrogen deposition less than 1 kg per hectare per year 

indicates “Good” condition, 1-3 kg per hectare per year indicates moderate (or “Somewhat 

Concerning”), and >3 kg per hectare per year indicates a “Significant Concern.” In the western 

Sierra Nevada, Fenn et al. (2008) recommended a threshold of 3.1 kg N per hectare per year to 

protect all components of the forest ecosystem from the adverse effects of N deposition. For the 

current assessment the most conservative category of <1 kg per hectare per year (NPS ARD 

2010) was used as the ecological threshold for water bodies. Lassen is the only park in the NPS 

Klamath Network with on-site monitoring of both wet and dry deposition of N and sulfate. 

Condition

Somewhat Concerning – Medium Certainty. Data from the park (Figures 23, 24) indicate the wet 

N deposition rate (2.18 kg N per ha per year, measured during the 2005-2009 period) is well 

within the Fenn et al. (2008) criteria described above, but does not meet the NPS guideline for 

“good” condition. Throughfall N deposition during 2000-2003 (exempting fire episodes) was 

measured at 1.4 kg N per hectare per year (Fenn et al. 2008). Measurements of N deposition in 

Lassen in 1996-1999 indicated 0.46-0.56 kg per hectare per year (inorganic N) dry deposition, 

but data for wet deposition were missing (Clow et al. 2002). The 2005-2009 CASTnet data 

indicate a dry deposition rate of 0.22 nitrate and 0.07 ammonium. The Western Airborne

Contaminants Assessment Project (Landers et al. 2008) found levels of N deposition in Lassen 

were not significantly higher than in other western parks.
83

Figure 23. Nitrate deposition at Lassen Volcanic National Park, 1988-2010. (IMPROVE web site: 

http://views.cira.colostate.edu/web )

Figure 24. N-deposition at Lassen Volcanic National Park, 1996-2010. (CASTnet)
84

Trends

Good – Medium Certainty. No trend is apparent in the graph of nitrate deposition.

4.5.4.2 Atmospheric Sulfate Deposition

Criteria

The NPS Air Resources Division has suggested the same criteria for sulfate deposition as for 

nitrogen deposition: less than 1 kg per hectare per year indicates “Good” condition, 1-3 kg per 

hectare per year indicates moderate (or “Somewhat Concerning”), and >3 kg per hectare per year 

indicates a “Significant Concern.” The current assessment uses the <1 kg per hectare per year to

evaluate the park’s condition.

Condition

Good – Medium Certainty. The park’s rate in 1996-1999 for dry deposition of sulfate was 0.13-

0.15 kg sulfate per hectare per year (Clow et al. 2002). CASTnet data covering 2005-2009

similarly indicates dry deposition of 0.15 kg sulfate per hectare per year, plus wet deposition of

1.16 sulfate per hectare per year in the park. This wet deposition rate is barely above the NPS

guideline for ecological effects, suggesting marginally degraded conditions. It is possible that

sulfate deposition levels may naturally be higher than the threshold in some localized areas of the

park that are near or fed by natural hot springs.

Trends

Somewhat Concerning – Medium Certainty. Although a trend is not obvious in graphs of sulfate 

dry deposition (Figures 25, 26), Lassen is one of only three sites nationwide that was reported to

show a statistically significant increase in 80th percentile sulfate concentration during the period

1988-1999 (Malm et al. 2002). The increase was 0.86 mg/m3 per 11-year time increment, or 

about a 32% increase, and levels are greater than expected at natural deposition rates. In contrast, 

Clow et al. (2003) found that sulfate (and nitrate) levels in the Lassen lakes they sampled were

significantly lower in 1999 than in 1985, but they cautioned this may have been due to annual

precipitation at Lassen being over 30% greater in the later year.
85

Figure 25. Sulfate deposition at Lassen Volcanic National Park, 1988-2010. Source: IMPROVE web site 

http://views.cira.colostate.edu/web

Figure 26. Sulfate deposition at Lassen Volcanic National Park, 1996-2010. Source: CASTnet.
86

4.5.4.3 Airborne Contaminant Deposition

Criteria

For other airborne contaminants, the preferred condition in the park is none.

Condition

Significant Concern – Medium Certainty. The Western Airborne Contaminants Assessment

Project (Landers et al. 2008) determined that lichens and conifers sampled at five sites were 

contaminated with several pesticides currently used outside the park, especially endosulfans and 

dacthal, but also chlorpyrifos and g-HCH (lindane), and historically-used DDT, 

hexachlorobenzene, chlordanes, dieldrin, and PCB. Lichens and/or conifers also had relatively 

high levels of PAHs (combustion by-products). These contaminants were also present in air 

samples at levels mostly greater than found in other western parks. Concentrations increased 

with elevation within the park. Also present in air samples at above-median concentrations were 

triuralin (an herbicide) and the historically-used pesticides chlordane, DDT, HCB, and a-HCH 

(alpha hexachlorocyclohexane). Concentrations of some pesticides in rain and snowmelt from 

the Sierras are generally below but sometimes near the published effects thresholds for aquatic 

invertebrates (McConnell et al. 1998) and amphibians (Dimitrie 2010) exposed to these 

chemicals. 

In 2001, evidence of DNA damage in juvenile frogs was documented in the park by Cowman 

(2005), who also found elevated levels of DDE in 15% of her samples, and found elevated levels 

of endosulfans in 9% of her samples. Contamination levels were significantly less than in frogs 

raised in Sequoia or Yosemite National Parks.

Trends

Indeterminate. No contaminants have been sampled in the same manner at Lassen over multiyear periods.

4.5.4.4 Ozone 

Criteria

The NPS-ARD (2010) guidance contains ozone criteria based on the average annual fourth 

highest daily maximum 8-hour ozone concentration for protecting human health, and two metrics

(SUM06 and W126) for evaluating risk to vegetation. Those were used for this assessment. The

California ozone standard is that ozone levels not exceed 0.07 ppm averaged over 8 hours.

Summarizing the literature, Geiser & Neitlich (2007) noted that ozone levels of 20 to 60 μg per

m3 may harm some lichens (Egger et al. 1994, Eversman and Sigal 1987) but repeated peak 

concentrations of 180-240 μg per m3 are more often the harmful threshold (Ross and Nash 1983,

Scheidegger and Schroeter 1995, Sigal and Nash 1983).
87

Table 13. Data from CASTnet show ozone levels at Lassen for the period 2005-2009:

OZONE

Concentration (ppb), 4th highest 8-hr 74.8

Sum06 (ppm-hr) 22.1

3-month cumulative 12-hr W126 13.2

Condition and Trends

Significant Concern – Medium Certainty. By NPS guidelines (NPS-ARD 2011), the 

concentration (74.8 ppb) is barely below the 76 ppb considered a “Significant Concern” level for 

human health. As well, the NPS guidelines indicate a “Significant Concern” with regard to ozone 

threat to vegetation at Lassen. Specifically, the Sum06 value of 22.1 ppm-hr is well above the 

NPS guideline of 15 ppm-hr, and above an 8 ppm-hr level which some studies have shown can 

damage vegetation. An older source (Odion et al. 2005) reported a Sum06 of 19.2 ppm/hr.

With regard to the W126 guideline, the value of 13.2 ppm-hr is slightly above the guideline of 13 

ppm-hr, and well above a threshold of 5.9 ppm-hr that has been shown to damage some sensitive 

plant species. An older source (Odion et al. 2005) reported a seasonal W126 of 35 ppm/hr from 

the park. Concern about the park’s ozone levels was also expressed by Jaffe et al. (2008) who 

analyzed data from several national parks. Also, limited surveys have found foliar symptoms of 

ozone injury to both ponderosa and jeffrey pine, and on approximately 20% of yellow pines 

studied near Manzanita Lake. Effects of ozone on yellow pine, as well as the incidence of 

pathogens and insects, were monitored in 1991-1995 and 2001 by Project FOREST (USFS

Riverside, Dr. Paul Miller). The American Lung Association

(http://www.stateoftheair.org/2011/states/california/tehama-06103.html) assigned an air quality

grade of F (failing) to Tehama County, which is one of the counties intersected by the park, but

noted an improving trend.

Ozone levels are known to have increased in the park from 1990-1999 (Odion et al. 2005). For a 

somewhat broader period (1987-2007), ozone increased significantly with a trend of 0.827 +/-

0.14% per year in daytime ozone concentrations (Oltmans et al. 2008).

Assessment Confidence and Data Gaps

Medium. The existing monitoring of ozone is probably adequate and should continue, but as is 

the case with N and S deposition, there has been little effort to quantify damage throughout the 

park to vegetation, especially to lichens and mosses.
88

4.6 Changes in the Natural Quality of the Park Experience

4.6.1 Background

Several attributes influence the natural quality of the park experience that is valued by most

visitors. Among these attributes are the absence of signs of human alteration, long-distance

visibility, a starlit night sky, and quiet surroundings. These are discussed here.

4.6.2 Regional Context

Lassen Volcanic National Park and the adjacent Caribou Wilderness together comprise the

largest contiguous protected area in northeastern California. They are within a day’s drive of San

Francisco, the Silicon Valley, Sacramento, Reno, and other major urban areas, providing

recreation and a connection with nature to hundreds of thousands of visitors each year.

4.6.3 Issue Description

While some infrastructure is obviously necessary to support the immediate safety and comfort of

visitors, some artificial features—mostly ones that remain from when land uses were unrestricted

before the park was established—can be a visual blight, can fragment wildlife habitat, disrupt

natural water flows, and provide an opportunity for the establishment of non-native plants.

Actively restoring or otherwise speeding the recovery of these areas is a priority for the National

Park Service. With increasing population growth projected for the region surrounding the park, 

an opportunity exists for more people to experience the park’s resources, including solitude, 

quiet settings, dark night skies, and clear distant views. However, air pollution, artificial lighting, 

and noise potentially threaten these attributes.

4.6.4 Indicators and Criteria to Evaluate Condition and Trends

Indicators that might be used to monitor this issue (Natural Quality of the Park Experience)

include the following:

1. Disturbed Area Recovery

2. Visibility

3. Dark night sky

4. Soundscape

5. Physical Remoteness and Solitude

These are now discussed individually.

4.6.4.1 Disturbed Area Recovery

Criteria 

For purposes of this assessment, “Good” conditions would be represented by a park landscape in 

which no lands have signs of being disturbed by humans except those lands currently vital to

visitor support. It would also involve complete restoration or recovery of all artificially disturbed

lands within the park that are not currently vital to visitor support. “Somewhat Concerning” and

“Significant Concern” would reflect increasing extent of unrestored lands.

Condition 
89

Somewhat Concerning – High Certainty. Historically disturbed lands not currently vital to visitor 

support are not extensive and were inventoried by Ziegbein & Wagner (2000). Since completion 

of that report, all have been physically restored and are being revegetated, with the following 

exceptions: 

1. A 1.1 acre gravel overflow parking area adjacent to the Peak parking lot.

2. The Inholders Road. There are three small private inholdings on Hat Creek totaling

about 1.5 acres.

3. Private cabins that line Juniper Lake. The park General Management Plan has the

stated goal of acquiring these inholdings on a "willing seller-willing buyer" basis, and

removing infrastructure as they are acquired.

4. The Twin Lakes ranger cabin. This is in a wilderness area and is currently

uninhabitable.

5. Parts of Manzanita Lake which originated when a dam was enlarged in 1911 for a

small hydro-power operation. Water was also diverted from Manzanita Creek to

Reflection Lake, originally a closed basin lake, to provide water-generated power and to

improve fish production.

The park contains 42 miles of paved roads, 15 miles of unpaved roads, five small bridges, and

146 miles of trails; however, these are currently vital to visitor support.

Trends

Improving – High Certainty. The NPS began successfully restoring the Drakesbad Meadow site

in 2006, and data and reports are available (Patterson 2005, Patterson & Cooper 2007). Filling of 

ditches that drained wetlands there has been completed, and Dream Lake has been drained and 

its dam removed. For the park as a whole, natural succession, aided by the planting of thousands 

of plugs and native seed, appears to be gradually leading to visual recovery in nearly all areas 

historically disturbed by earth-moving, logging, clearing (former ski hill), or grazing. 

Assessment Confidence and Data Gaps

High. The Ziegbein & Wagner (2000) survey established a baseline, and park managers not only 

have made steady progress in remedying nearly all the disturbances noted, but have monitored 

ecological recovery following the completion of the most important restoration efforts. 

4.6.4.2 Visibility

Visibility is the clarity of the atmosphere, as typically measured by the viewable distance at a

particular location and time, and the number of days annually that scenic objects at different

distances can be seen. Visibility is restricted by the absorption and scattering of light that is

caused by both gases and particles in the atmosphere. Natural factors that decrease visibility

include relative humidity above 70 percent, fog, precipitation, blowing dust and snow, and

smoke from wildland fires. Human activities reduce visibility when soil is disturbed and creates

dust, as well as when fossil fuels are burned which results in soot and tiny visibility-reducing

particles (aerosols). In rural areas such as near Lassen, the greatest contributors to reduced

visibility are carbon and especially sulfate. An NPS study in the Pacific Northwest during the
90

summer of 1990 found that sulfates accounted for over 40% of the visibility reduction, whereas 

carbon (organics and light absorbing carbon) was responsible for about 20% and nitrates and 

coarse mass was responsible for 10%. Measurements in the spring of 2002 noted that the 

majority of dust in northern California came from long-range transport across the Pacific 

(Cameron-Smith et al. 2005).

The park is in a designated Class I air quality area, and the USEPA has regional haze regulations

that require states to establish goals for each such area, to improve visibility on the haziest days

and ensure no degradation occurs on the clearest days. For this park specifically, the California

Regional Haze Plan has suggested that the worst condition expected under natural circumstances 

is about 7.3 deciview (dv). One deciview represents the minimal perceptible change in visibility

to the human eye.

Criteria

The visibility criteria used by the NPS are based on the deviation of the current Group 50

visibility conditions from estimated Group 50 natural visibility conditions, where Group 50 is

defined as the mean of the visibility observations falling within the range from the 40th through

the 60th percentiles. Visibility is estimated from the interpolation of the five-year averages of the

Group 50 visibility. Visibility in this calculation is expressed in terms of a Haze Index in 

deciviews: as the Haze Index increases, the visibility worsens. The visibility condition is

expressed as current Group 50 visibility minimums, the estimated Group 50 visibility under

natural conditions.

“Good” condition is assigned to parks with a visibility condition estimate of less than 2 dv above

estimated natural conditions. Parks with visibility condition estimates of 2-8 dv above natural

conditions are considered to be in “Moderate” condition (or “Somewhat Concerning”) and parks

with visibility condition estimates greater than 8 dv above natural conditions are considered to

have a “Significant Concern.” The NPS chose the dv ranges of these categories to reflect as

nearly as possible the variation in visibility conditions across the nation’s visibility monitoring

network.

Condition 

Somewhat Concerning – High Certainty. As part of the IMPROVE15 network, Lassen visibility

has been monitored using an aerosol sampler (1988-present) and an automatic 35mm camera

(1988-1995). The average visual range in the park is about 175 km (108 miles). Although this is

better than in many parts of the United States, visibility is often noticeably impaired by haze. The

most recent NPS assessment (NPS-ARD 2011), measured during 2006-2010, suggests the 

condition of the park’s visibility should be categorized as “Somewhat Concerning” because the

average annual Group 50 visibility after adjustment for natural conditions was measured as 3.5

dv.

 

15 Interagency Monitoring of Protected Visual Environments 
91

Trends

Indeterminate. Although not obvious from the graph (Figure 27), the NPS-ARD (2002) analysis 

of 1989-2008 IMPROVE data indicated that visibility in the area improved significantly on the 

clearest days during that period and may have degraded on the haziest days (but was not 

statistically significant).

Figure 27. Visibility (in deciview units) from the park, 1988-2005. (IMPROVE web site: 

http://views.cira.colostate.edu/web )

Assessment Confidence and Data Gaps

High. The IMPROVE data describe the visibility conditions well.

4.6.4.3 Dark Night Sky

Natural lightscapes are critical for nighttime scenery, such as viewing a starry sky in its finest 

detail. They are also critical for maintaining nocturnal habitat of many wildlife species which 

rely on natural patterns of light and dark for navigation, to cue behaviors, or to hide from

predators. Human-caused light may be obtrusive in the same manner that noise can disrupt a

contemplative or peaceful scene; light that is undesirable in a natural or cultural landscape is

often called "light pollution."

Criteria 

The NPS has developed a system for measuring sky brightness to quantify the source and

severity of light pollution. This system, developed with the assistance from professional

astronomers and the International Dark-Sky Association, utilizes a research-grade digital camera

to capture the entire sky with a series of images. Sky brightness is measured in astronomical

magnitudes in the V-band, abbreviated as "mags." The V-band measures mostly green light,

omitting purple through ultraviolet and orange through infrared. The magnitude scale is a
92

logarithmic scale: a difference of 5 magnitudes corresponds to a 100x difference in brightness; 

lower values (smaller or more negative) are brighter.

Condition 

Good – Medium Certainty. Because of its isolation from urban areas and other major sources of 

artificial light, the park’s night sky can probably be assumed to be in good condition. However, 

data are few. Baseline condition was established for the park on July 16, 2004, when an NPS

team imaged the night sky using the NPS protocol. The condition then was interpreted as “a

pretty dark site.” Numbers supporting that assessment are reported at:

http://www.nature.nps.gov/air/lightscapes/monitordata/Lassen/lp20040716.cfm

Trends

Indeterminate. It can be assumed that nighttime light levels have increased somewhat over those 

present when the park was created, as surrounding areas have slowly become more developed. 

However, the rate at which this is has occurred is unknown.

Assessment Confidence and Data Gaps

Medium, due to the night sky condition having been measured only once using a standard 

protocol, and with no comparison to a quantified reference standard. 

4.6.4.4 Soundscape

Criteria 

Since 2006, the National Park Service has required parks to identify the levels and types of

unnatural sound that constitute acceptable and unacceptable impacts on park natural

soundscapes. This is not only for the benefit of visitors, but also to protect species that require

often-subtle auditory cues for reproduction, predator avoidance, navigation, and communication

about food locations. Data necessary to establish reference condition criteria or a baseline for

Lassen have not been collected.

Condition

Good – Medium Certainty. Because of its isolation from urban areas and other major sources of 

noise, the park’s soundscape can probably be assumed to be in good condition overall. However, 

data are lacking. Senior staff in 2009 noted the following important components of the park’s 

soundscape:

Wildlife. During the morning and throughout the day, the vocalizations of songbirds are 

a dominant feature, along with the chattering of chipmunks and squirrels. Pika can be 

heard frequently in alpine areas and the low throbbing call of blue grouse at edge of fir 

forests. In the evening and at night, tree frogs and crickets are common, along with owls 

(great-horned, spotted, saw-whet) and coyotes.

Water. Flowing water in streams and waterfalls, water dripping off of snow banks. Near 

geothermal areas, the sounds of steam hissing and mud pots bubbling.

Wind. Especially on high peaks, and the silence of snowfall, heavy and light rainfall on 

vegetation and the ground, and occasionally some terrific thunderstorms. Leaves rustling, 

particularly aspen and cottonwood. Wind blowing through the trees, and trees 

creaking/rubbing against each other. 
93

They further noted the presence of loud sounds that sometimes adversely affect the park’s 

acoustical environment and soundscape:

Vehicle traffic on park roads. This intrusion can be heard from many places in the park. 

Traffic is generated from many sources (visitors, staff, contractors) using many vehicle 

types. The most intrusive noises tend to be generated from big rigs and motorcycles, 

although noise from passenger cars and RVs is persistent during the day.

Hikers. Laughing and talking on trails and in the backcountry, particularly when they are 

on the Lassen Peak trail. These sounds can be heard from areas surrounding peak.

Campground and day use area noise. Generators, music, doors slamming etc. This 

tends to be concentrated, and because the campgrounds are in well-vegetated areas, the 

sounds do not travel far.

Construction and maintenance noise. Work on and around buildings and other facilities 

such as bridges and campground areas can be very noisy. The plowing that is a part of the 

spring road opening is very loud, but humans other than the roads crew are generally not 

around to hear it.

Aircraft. This intrusion is mostly high elevation commercial flights but heard regularly 

everywhere in park. Occasionally what sounds like a military overflight goes past; these 

have been heard in the Butte Lake area (northeast part of park) and circling the parks 

higher peaks. Aircraft used in fire suppression and fire monitoring also have an impact, 

and helicopters occasionally pass over the park.

Forestry work. This intrusion is created by chainsaws, chippers, and other powered 

equipment used to cut hazard trees or to do thinning in campground areas and for some 

trail work. These sounds are significant but infrequent and irregular in occurrence.

Trends

Indeterminate. It can probably be assumed that as visitation has increased, noise levels have 

increased somewhat over those present when the park was created. However, trends data are 

lacking.

Assessment Confidence and Data Gaps

Medium, but quantitative data are lacking. 

4.6.4.5 Physical Remoteness and Solitude

Wilderness qualities, each of which has been defined administratively, are:

• Untrammeled

• Natural

• Undeveloped

• Solitude or primitive and unconfined recreation quality

Criteria 

For Lassen, several indicators and measures of these—but not criteria—are described in a report 

“Wilderness Stewardship Core Elements” (Tarpinian 2010).
94

Condition 

Good – Medium Certainty. Most of the park visitors who seek it are likely to find many

opportunities for physical remoteness and solitude. This is partly the result of the park’s 

protective resource management practices: wilderness use is concentrated at lakes along a few

popular loop trails, and a few areas of designated and proposed wilderness are off-limits to

overnight camping in order to prevent damage to sensitive areas—including Hot Springs Creek

and Devil’s Kitchen, and the area around Cinder Cone and Painted Dunes. Policies also prohibit

campfires throughout the designated and proposed wilderness. Horseback riders must remain on

particular trails, and even then, riding is allowed only when the potential for muddy conditions is

low. About 400,000 visitors come to the park each year, mainly between June and September.

Most visitors spend the bulk of their time in the developed zone along the main park road

between Mineral and Manzanita Lake.

Trends

Indeterminate. It can probably be assumed that as visitation has increased, the sense of physical 

remoteness and solitude has decreased somewhat over what was present when the park was 

created. However, trends data are lacking.

Assessment Confidence and Data Gaps

Medium. Although total visits to the park are tallied annually, visits to various areas (especially 

wilderness areas) are not routinely tallied, nor are the disturbances potentially associated with 

those visits. The park will be producing a new Wilderness Stewardship Plan that will guide long

term wilderness management in the park.
95

5.0 Discussion 

Table 14 summarizes what this document has reported about the condition and trend of each of

the major resource concerns at Lassen Volcanic National Park. Based on existing data, this 

review noted that a significant concern is the distorted age distributions of forest stands and 

lengthened fire rotations as a result of fire suppression. This will restrict the park’s capacity to

effectively support the region’s wildlife and plant diversity—in particular, early successional 

vegetation like aspen and chaparral. Forest succession in the absence of fire has made fir 

dominant in much of the park. These changes may be reversed by fire; however, lack of fire also 

helps minimize the local loss of native plant species as a result of invasive plants, and helps 

maintain habitat for late-successional species. This creates a resource management conundrum. 

Another significant concern is air quality, particularly the increasing levels of ozone. Also, 

restriction of long-distance visibility as a result of airborne particulates was rated “somewhat 

concerning,” as were potential threats to native amphibians (as indicated by the very recent 

extirpation from the park of Cascades frog). Snowfall is a key water source for the park’s many 

ponds, wetlands, and streams, as well as some native subalpine plants and animals. However, its 

annual depth distribution and melting phenology have not been measured throughout the park. 

This is a concern, given the inevitability of climate change. Understanding the condition and

trends of the park’s natural resources is essential to their sound management and could benefit

from new or expanded research on the extent of ozone damage to vegetation, the extent of blister 

rust infection in whitebark pine, and the effects of airborne contaminants and vegetation change 

on amphibians. Also, given the probability of climate warming in this region, more regular and

extensive monitoring is warranted of the park’s subalpine plants and animals (e.g., gray-crowned

rosy finch), timing and amount of snowmelt, stream flows and points of flow initiation, pond and 

wetland water quality, aquatic plants (especially invasives), and aquatic invertebrates.
96

Table 14. Summary of ratings for indicators of natural resource condition and trend used in this analysis of Lassen Volcanic National Park. See 

chapter narratives for criteria and justification of each rating. “Spatial coverage” refers to the extent and spatial resolution of data from the park that 

is suitable for assessing that indicator’s condition. “Temporal coverage” refers to the length of time period and frequency of measurement with 

which that indicator has been measured in the park.

Table 14.

Priority 

Issue Indicators

Potential 

Value as 

Indicator

Condition 

Rating Certainty

Trend 

Rating Certainty

Spatial 

Coverage

Temporal 

Coverage

Changes in 

Precipitation, 

Snowpack, 

and Water 

Availability

Maximum Annual Depth and 

Volume of Snowpack

Excellent Indeterminate Somewhat 

Concerning

Low Poor Poor

Timing and Rate of Spring Melt and 

Discharge in Springs and Streams

Excellent Indeterminate Somewhat 

Concerning

Low Poor Poor

Perennial Stream Extent, Seasonal 

Flow Volume, Wetted Width

Good Indeterminate Indeterminate Poor Poor

Number, Area, and Distribution 

Pattern of Wetlands, Ponds, and 

Lakes

Good Good Medium Indeterminate Excellent Poor

Changes in 

Surface 

Waters & 

Their 

Resources

Water Quality Threshold 

Exceedances

Fair Good Low Indeterminate Fair Poor

Diversity of Native Aquatic Species 

and Habitats

Fair Somewhat 

Concerning

Low Indeterminate Poor Poor

Water Bodies With Ecologically 

Harmful Species

Good Somewhat 

Concerning

Low Indeterminate Medium Good Poor
97

Table 14.

Priority 

Issue Indicators

Potential 

Value as 

Indicator

Condition 

Rating Certainty

Trend 

Rating Certainty

Spatial 

Coverage

Temporal 

Coverage

Changes in 

Terrestrial 

Vegetation

Distributions of Stand Age Classes Excellent Significant 

Concern

Medium Significant 

Concern

Medium Good Fair

Fire Rotations Good Somewhat 

Concerning

Medium Somewhat 

Concerning

Medium Good Fair

Changes in Abundance of Major 

Vegetation Types

Good Somewhat 

Concerning

Medium Somewhat 

Concerning

Medium Good Fair

Invasive Plants Fair Somewhat 

Concerning

Medium Medium Fair Poor

Invasive Pathogens Fair Significant 

Concern

Very Low Significant 

Concern

Poor Poor Poor

Rare Plant Species and Species 

Diversity

Poor Indeterminate Low Indeterminate Poor Poor

Changes in 

Wildlife

Presence and Persistence of 

Native Terrestrial Wildlife Species

Fair Good Low Indeterminate Fair Fair

Connectivity and Extent of 

Important Terrestrial Habitats

Good Good Medium Good Low Good Poor
98

Table 14.

Priority 

Issue Indicators

Potential 

Value as 

Indicator

Condition 

Rating Certainty

Trend 

Rating Certainty

Spatial 

Coverage

Temporal 

Coverage

Changes in 

Air Quality

Atmospheric Nitrogen Deposition Fair Somewhat 

Concerning

Medium Good Medium Poor Good

Atmospheric Sulfate Deposition Fair Good Medium Somewhat 

Concerning

Medium Poor Good

Airborne Contaminants Deposition Fair Significant 

Concern

Medium Indeterminate Poor Poor

Ozone Good Significant 

Concern

Medium Significant 

Concern

Medium Poor Good

Changes in 

the Natural 

Quality of 

the Park 

Experience

Disturbed Area Recovery

Fair

Somewhat 

Concerning

High Improving High Excellent Poor

Visibility Good Somewhat 

Concerning

High Indeterminate Poor Poor

Dark Night Sky Good Good Medium Indeterminate Poor Poor

Soundscape Good Good Medium Medium Poor Poor

Physical Remoteness and Solitude Fair Good Medium Indeterminate Excellent Poor
99

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A-1

Appendix A. Climate of Lassen Volcanic National Park 

supporting data and maps
A-2

Figure A1. Average annual precipitation for Lassen Volcanic National Park (LAVO) from the PRISM 

1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all 

grids that fall within the park boundary.
A-3

Figure A2. Average annual temperatures for Lassen Volcanic National Park (LAVO) from the PRISM 

1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all 

grids that fall within the park boundary.
A-4

Figure A3. Average annual maximum temperatures for Lassen Volcanic National Park (LAVO) from the 

PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles 

of all grids that fall within the park boundary.
A-5

Figure A4. Average annual minimum temperatures for Lassen Volcanic National Park (LAVO) from the 

PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles

of all grids that fall within the park boundary. 
A-6

Figure A5. Average precipitation for the winter (DJF), spring (MAM), summer (JJA), and fall SON) seasons for Lassen Volcanic National Park 

(LAVO) from the PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all grids that fall 

within the park boundary.
A-7
A-8

Figure A6. Average temperatures for the winter (DJF), spring (MAM), summer (JJA), and fall SON) seasons for Lassen Volcanic National Park 

(LAVO) from the PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all grids that fall 

within the park boundary.
A-9
A-10

Figure A7. Average maximum temperatures for the winter (DJF), spring (MAM), summer (JJA), and fall SON) seasons for Lassen Volcanic 

National Park (LAVO) from the PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all 

grids that fall within the park boundary.
A-11

Figure A8. Average minimum temperatures for the winter (DJF), spring (MAM), summer (JJA), and fall SON) seasons for Lassen Volcanic 

National Park (LAVO) from the PRISM 1971-2000 Climate Normals (Daly et al. 2008). The inset table gives the spatially derived quartiles of all 

grids that fall within the park boundary.
A-12

Figure A9. Climate stations in the vicinity of Lassen Volcanic National Park (LAVO) (Daly et al. 2009). 

Stations highlighted in the map are further referenced in the report. 
A-13

Figure A10. 1971–2000 average monthly average temperature for the stations at Chester, Manzanita 

Lake, Mineral, and the Lassen NP (LAVO) park average of the PRISM modeled data (Daly et al. 2009). 

Date refers to the month of the year.
A-14

Figure A11. 1971–2000 average monthly maximum temperature for the stations at Chester, Manzanita 

Lake, Mineral, and the Lassen NP (LAVO) park average of the PRISM modeled data (Daly et al. 2009). 

Date refers to the month of the year. 

Figure A12. 1971–2000 average monthly minimum temperature for the stations at Chester, Manzanita 

Lake, Mineral, and the Lassen NP (LAVO) park average of the PRISM modeled data (Daly et al. 2009). 

Date refers to the month of the year. 
A-15

Figure A13. 1971–2000 average monthly daily temperature rangefor the stations at Chester, Manzanita 

Lake, Mineral, and the Lassen NP (LAVO) park average of the PRISM modeled data (Daly et al. 2009). 

Date refers to the month of the year. 

Figure A14. 1971–2000 average monthly precipitation for the stations at Chester, Manzanita Lake, 

Mineral, and the Lassen NP (LAVO) park average of the PRISM modeled data (Daly et al. 2009). Date 

refers to the month of the year. 
A-16

Figure A15. 1971–2000 average monthly snowfall for the stations at Chester, Manzanita Lake, and 

Mineral (Daly et al. 2009). Date refers to the month of the year.

Figure A16. 1971–2000 average first of the month snow depth for the stations at Chester, Manzanita 

Lake, and Mineral (Daly et al. 2009). Date refers to the month of the year.
A-17

Figure A17. Time series of mean annual temperature for LAVO from the park average of the PRISM 

modeled data. Black line is a 5 year moving average and the blue line is the trend associated with the 

regression parameters (inset) (Daly et al. 2009). Date refers to year.

Figure A18. Time series of mean annual maximum temperature for LAVO from the park average of the 

PRISM modeled data (Daly et al. 2009). Black line is a 5 year moving average and the blue line is the 

trend associated with the regression parameters (inset). Date refers to year.
A-18

Figure A19. Time series of mean annual minimum temperature for LAVO from the park average of the 

PRISM modeled data (Daly et al. 2009). Black line is a 5 year moving average and the blue line is the 

trend associated with the regression parameters (inset). Date refers to year.

Figure A20. Time series of mean annual daily temperature range for LAVO from the park average of the 

PRISM modeled data (Daly et al. 2009). Black line is a 5 year moving average and the blue line is the 

trend associated with the regression parameters (inset). Date refers to year. 
A-19

Figure A21. Time series of annual precipitation for LAVO from the park average of the PRISM modeled 

data. Black line is a 5 year moving average and the blue line is the trend associated with the regression 

parameters (inset) (Daly et al. 2009). Date refers to year. 

Figure A22. Time series of April 1st snow depth for Manzanita Lake. Black line is a 5 year moving 

average and the blue line is the trend associated with the regression parameters (inset) (Daly et al. 2009). 

Date refers to year.
A-20
A-21

Table A1. Regression parameters and statistics for core climate elements for different time periods for Lassen Volcanic National Park using 

PRISM modeled data (Daly et al. 2009). Slope p-values significant at the 90% confidence level (α=0.10) are shown in bold.

Annual Precipitation

Annual Maximum 

Temperature

Annual Minimum 

Temperature Annual Mean Temperature

Time Period 

(years)

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

1895–2007 -3.544 0.810 0.020 0.356 -0.073 0.000 -0.026 0.105

1971–2007 45.121 0.613 0.136 0.251 0.322 0.003 0.228 0.009
A-22

Table A2. Regression parameters and statistics for core climate elements for 1895–2007 for Lassen Volcanic National Park using PRISM 

modeled data (Daly et al. 2009). Slope p-values significant at the 90% confidence level (α=0.10) are shown in bold.

Precipitation Maximum Temperature Minimum Temperature Mean Temperature

Month

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

January -8.033 0.231 0.094 0.138 -0.029 0.596 0.033 0.538

February -1.515 0.774 0.043 0.517 -0.084 0.122 -0.020 0.700

March -2.672 0.527 0.059 0.433 -0.022 0.630 0.018 0.746

April 3.137 0.388 -0.088 0.251 -0.070 0.085 -0.079 0.158

May -0.793 0.710 0.044 0.552 0.005 0.910 0.024 0.654

June -0.618 0.580 0.012 0.834 -0.034 0.364 -0.011 0.810

July 0.524 0.112 0.005 0.915 -0.090 0.025 -0.042 0.291

August 0.961 0.251 0.033 0.502 -0.127 0.001 -0.048 0.217

September -1.199 0.314 0.138 0.020 -0.089 0.029 0.024 0.588

October -1.738 0.585 0.032 0.646 -0.100 0.009 -0.034 0.483

November 0.460 0.925 -0.079 0.256 -0.134 0.001 -0.106 0.024

December 7.942 0.216 -0.048 0.416 -0.107 0.038 -0.077 0.115

Annual -3.544 0.810 0.020 0.356 -0.073 0.000 -0.026 0.105
A-23

Table A3. Regression parameters and statistics for core climate elements for 1971–2007 for Lassen Volcanic National Park using PRISM 

modeled data (Daly et al. 2009). Slope p-values significant at the 90% confidence level (α=0.10) are shown in bold. 

Precipitation Maximum Temperature Minimum Temperature Mean Temperature

Month

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

January 6.559 0.838 -0.101 0.711 0.479 0.068 0.187 0.391

February 15.436 0.579 -0.075 0.829 0.183 0.476 0.054 0.830

March -22.069 0.394 0.697 0.070 0.444 0.073 0.570 0.052

April 24.257 0.185 0.060 0.882 0.430 0.037 0.245 0.407

May 15.691 0.205 -0.042 0.917 0.381 0.062 0.169 0.554

June 1.226 0.816 0.009 0.978 0.219 0.312 0.113 0.646

July -1.975 0.315 0.302 0.251 0.362 0.124 0.332 0.160

August -10.336 0.045 0.210 0.381 0.182 0.376 0.196 0.321

September -12.479 0.043 0.332 0.328 0.301 0.166 0.316 0.213

October -12.301 0.358 0.197 0.619 0.207 0.268 0.202 0.438

November -28.241 0.352 0.275 0.482 0.239 0.310 0.257 0.348

December 69.352 0.069 -0.227 0.512 0.427 0.128 0.100 0.706

Annual 45.121 0.613 0.136 0.251 0.322 0.003 0.228 0.009
A-24

Table A4. Regression parameters and statistics for core climate elements for 1971–2007 at Chester (Daly et al. 2009). Slope p-values significant

at the 90% confidence level (α=0.10) are shown in bold. 

Precipitation Maximum Temperature Minimum Temperature Mean Temperature

Month

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

January 17.057 0.397 -0.572 0.030 0.733 0.044 0.083 0.727

February 11.221 0.506 -0.701 0.069 0.225 0.457 -0.239 0.346

March -8.295 0.623 0.082 0.852 0.285 0.202 0.186 0.526

April 10.253 0.092 -0.291 0.507 0.607 0.005 0.158 0.594

May 8.245 0.136 -0.265 0.480 0.729 0.001 0.247 0.332

June 0.422 0.874 -0.339 0.328 0.588 0.014 0.120 0.647

July -0.096 0.953 0.101 0.699 0.979 0.000 0.534 0.023

August -3.601 0.094 0.012 0.963 0.801 0.000 0.404 0.030

September -7.411 0.025 -0.091 0.788 0.718 0.000 0.310 0.143

October -5.363 0.450 -0.207 0.624 0.441 0.020 0.057 0.824

November -8.743 0.496 -0.394 0.385 0.395 0.106 -0.009 0.975

December 20.209 0.181 -0.536 0.113 0.517 0.165 -0.012 0.967

Annual 38.612 0.455 -0.256 0.099 0.589 0.000 0.162 0.116
A-25

Table A5. Regression parameters and statistics for core climate elements for 1971–2007 at Manzanita Lake (Daly et al. 2009). Slope p-values 

significant at the 90% confidence level (α=0.10) are shown in bold. 

Precipitation Maximum Temperature Minimum Temperature Mean Temperature

Month

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

January 12.428 0.443 -0.431 0.199 0.357 0.190 -0.041 0.879

February -2.275 0.869 -0.189 0.626 0.101 0.721 -0.049 0.870

March -12.888 0.360 0.451 0.231 0.415 0.205 0.438 0.190

April 8.054 0.382 0.674 0.226 0.603 0.077 0.636 0.149

May 11.307 0.233 0.053 0.917 0.320 0.216 0.188 0.604

June -1.784 0.730 0.208 0.554 0.023 0.922 0.110 0.692

July -1.375 0.498 0.312 0.365 0.167 0.530 0.232 0.417

August -6.893 0.049 0.341 0.283 -0.009 0.970 0.141 0.579

September -10.817 0.029 0.689 0.073 0.166 0.500 0.427 0.152

October -10.702 0.226 0.205 0.644 -0.020 0.927 0.098 0.754

November -15.706 0.341 0.038 0.929 -0.051 0.852 -0.014 0.967

December 19.989 0.260 -0.715 0.096 0.089 0.803 -0.316 0.377

Annual 25.920 0.747 0.142 0.449 0.207 0.096 0.169 0.193
A-26

Table A6. Regression parameters and statistics for core climate elements for 1971–2007 at Mineral (Daly et al. 2009). Slope p-values significant

at the 90% confidence level (α=0.10) are shown in bold. 

Precipitation Maximum Temperature Minimum Temperature Mean Temperature

Month

Slope 

(mm/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope 

(°C/10 yr) p-value

Slope

(°C/10 yr) p-value

January 19.601 0.513 0.037 0.894 0.524 0.110 0.288 0.233

February 15.053 0.538 -0.008 0.983 0.054 0.866 -0.035 0.900

March -19.239 0.416 0.788 0.047 0.251 0.246 0.522 0.057

April 12.511 0.314 0.245 0.541 0.343 0.078 0.286 0.302

May 13.917 0.186 -0.076 0.865 0.485 0.007 0.208 0.458

June -0.503 0.925 0.325 0.335 0.329 0.131 0.320 0.198

July -3.542 0.112 0.392 0.249 0.275 0.264 0.397 0.146

August -4.286 0.062 0.357 0.241 0.048 0.768 0.204 0.340

September -12.908 0.067 0.932 0.072 0.411 0.027 0.673 0.032

October -15.165 0.232 0.969 0.055 0.042 0.794 0.505 0.089

November -13.447 0.615 0.382 0.371 0.271 0.296 0.320 0.265

December 54.259 0.117 0.023 0.945 0.492 0.116 0.253 0.344

Annual 76.714 0.480 0.312 0.081 0.308 0.012 0.300 0.008
A-27

Table A7. Regression parameters and statistics for April 1st snow depth at Manzanita Lake for different time periods (Daly et al. 2009). Slope pvalues significant at the 90% confidence level (α=0.10) are shown in bold. 

April 1

Snow Depth

Time Period 

(years)

Slope 

(mm/10 yr) p-value

1949–2007 -67.984 0.050

1971–2007 -35.379 0.560
A-28

Table A8. Regression statistics for the 27 core climate extremes indices for the three representative climate stations for LAVO. All trends 

statistically significant at the 0.05 level shown in bold.

Indices/Stations/Trend Statistics

Chester (1957-2011) Mineral (1927-2011) Manzanita Lake (1949-2011)

R2 p-value Slope R2 p-value Slope R2 p-value Slope

# of Days Tmax >25°C (days) NS 0.998 0.000 0.08 0.006 0.144 NS 0.734 -0.014

# of Days Tmax <0°C (days) NS 0.477 0.040 0.04 0.046 -0.013 0.06 0.049 0.163

# of Days Tmin >20°C (days) NS 0.596 0.001 Not Observed Not Observed

# of Days Tmin <0°C (days) 0.15 0.008 -0.435 0.49 0.000 -0.694 0.15 0.001 0.272

# of Days Tmin <-10°C (days) 0.16 0.006 -0.309 0.10 0.002 -0.043 NS 0.831 0.012

Growing Season Length (days) NS 0.854 -0.031 0.14 0.000 0.403 NS 0.341 -0.201

Maximum Tmax (°C) NS 0.080 0.024 NS 0.467 0.004 NS 0.513 -0.006

Minimum Tmax (°C) NS 0.226 -0.032 0.05 0.028 0.017 NS 0.518 0.009

Maximum Tmin (°C) NS 0.496 0.015 0.17 0.000 0.025 0.24 0.000 -0.045

Minimum Tmin (°C) NS 0.244 0.042 0.11 0.001 0.046 0.09 0.013 0.037

% of Days Tmax <10th Percentile (%) NS 0.412 0.016 0.25 0.000 -0.068 NS 0.305 0.017

% of Days Tmax >90th Percentile (%) NS 0.476 -0.016 0.05 0.030 0.029 NS 0.138 -0.034

% of Days Tmin <10th Percentile (%) 0.11 0.001 -0.124 0.47 0.000 -0.136 NS 0.314 0.015

% of Days Tmin >90th Percentile (%) 0.21 0.025 0.056 0.56 0.000 0.109 0.22 0.000 -0.091

Warm Spell Duration Index (days) NS 0.056 -0.077 NS 0.939 -0.002 NS 0.088 -0.067

Cold Spell Duration Index (days) NS 0.911 -0.005 0.21 0.000 -0.097 NS 0.326 0.013
A-29

Indices/Stations/Trend Statistics

Chester (1957-2011) Mineral (1927-2011) Manzanita Lake (1949-2011)

R2 p-value Slope R2 p-value Slope R2 p-value Slope

Diurnal Temperature Range (°C) 0.25 0.001 -0.029 0.15 0.000 -0.013 NS 0.924 0.000

Maximum 1-Day Precipitation (mm) NS 0.825 -0.026 NS 0.632 0.032 0.06 0.042 -0.431

Maximum 5-Day Precipitation (mm) NS 0.446 0.176 NS 0.800 0.044 NS 0.174 -0.456

Simple Precipitation Intensity Index (mm/day) NS 0.086 0.016 NS 0.896 -0.001 0.12 0.003 -0.030

Annual # of Days Precipitation >10 mm (days) NS 0.123 0.053 NS 0.688 0.011 NS 0.950 -0.004

Annual # of Days Precipitation >20 mm (days) 0.11 0.020 0.052 NS 0.310 0.017 NS 0.536 -0.025

Maximum Length of Dry Spell (days) NS 0.948 0.007 NS 0.648 -0.033 NS 0.842 -0.018

Maximum Length of Wet Spell (days) NS 0.368 -0.016 NS 0.497 0.010 NS 0.692 -0.007

Annual # of Days with Precipitation >95 Percentile 

(days) NS 0.196 0.782 NS 0.736 0.158 0.10 0.006 -3.059

Annual # of Days with Precipitation >99 Percentile 

(days) NS 0.935 0.027 NS 0.860 -0.045 0.14 0.001 -2.204

Annual Precipitation Total (mm) NS 0.333 0.934 NS 0.509 0.491 NS 0.291 -1.860
A-30

Figure A23. Example time series of the changes in the diurnal temperature range during the reference 

period observed each year at Chester, California, during 1957-2011. Trends are computed by linear least 

square (solid line) and locally weighted linear regression (dashed line). Missing data is handled as 

discussed in the text.

Figure A24. Example time series of the number of days below -10°C (14°F) observed each year at 

Chester, California, during 1957-2011. Trends are computed by linear least square (solid line) and locally 

weighted linear regression (dashed line). Missing data is handled as discussed in the text.
A-31

Figure A25. Example time series of the number of days when the minimum temperature is below the 10th

percentile during the reference period observed each year at Chester, California, during 1957-2011. 

Trends are computed by linear least square (solid line) and locally weighted linear regression (dashed 

line). Missing data is handled as discussed in the text.

Figure A26. Example time series of the number of days when the maximum temperature is below the 10th

percentile during the reference period observed each year at Manzanita Lake, California, during 1949-

2011. Trends are computed by linear least square (solid line) and locally weighted linear regression 

(dashed line). Missing data is handled as discussed in the text.

B-1

Appendix B. Physical Characteristics of Lassen Volcanic 

National Park: supporting data and maps
B-2

Figure B1. Mapped elevation classes in Lassen Volcanic National Park (USGS 2011). Scale: 10 meters.
B-3

Figure B2. Mapped slope classes in Lassen Volcanic National Park (USGS 2011). Scale: 10 meters.
B-4

Figure B3. Mapped aspect classes in Lassen Volcanic National Park (USGS 2011). Scale: 10 meters. 

This is a raster file that identifies the orientation or direction of slope. Aspect is the down-slope direction of 

a cell to its neighbors. The cell values in an aspect grid are compass directions ranging from 0° to 360°; 

north is 0° and, in a clockwise direction, 90° is east, 180° is south, and 270° is west. Input grid cells that 

have 0° slope (flat areas) are assigned an aspect value of -1. This file was created from the DEM using 

the Aspect tool located in the Spatial Analyst toolbox provided in the ArcGIS software.
B-5

Figure B4. Mapped lithologic classes in Lassen Volcanic National Park (USGS 2005). Scale: 

1:500,000 (Chris Wayne, NPS Klamath Network, pers. comm.)
B-6

Figure B5. Mapped soil complexes in Lassen Volcanic National Park. Scale: 1:24,000. The SSURGO soil 

data map was simplified by using the dissolve tool, located in the Data Management toolbox provided in 

ArcGIS software, to combine multiple shapefiles of the same soil type into one single shapefile. The 

single shapefile was then grouped with other dissolved soil shapefiles of the same soil complex root 

name. The final output was single shapefiles of soil complexes, each containing multiple individual soil 

types from the same soil complex. The goal of 'simplifying' the data was to make the map less congested 

and easier to read.
C-1

Appendix C. Vegetation and Fire-related Characteristics of 

Lassen Volcanic National Park: supporting data and maps
C-2

Table C1. Invasive plant species found in Lassen Volcanic National Park.

Species Common name Family Park-Status Abundance Highly invasive

Agrostis gigantea Roth redtop Poaceae Present in Park Uncommon No

Alopecurus pratensis L. meadow foxtail Poaceae Unconfirmed NA No

Alyssum minus ssp. micranthum alyssum Brassicaceae Encroaching NA No

Bromus inermis Leyss. ssp. inermis smooth brome Poaceae Present in Park Uncommon No

Bromus tectorum L. cheatgrass Poaceae Present in Park Uncommon Yes

Capsella bursa-pastoris (L.) Medik. shepherd's purse Brassicaceae Present in Park Uncommon No

Carduus nutans musk thistle Asteraceae Unconfirmed Uncommon Yes

Centaurea stoebe ssp. micranthos spotted knapweed Asteraceae Encroaching NA Yes

Cerastium fontanum Baumg. ssp. 

vulgare (Hartman) Greuter & Burdet big chickweed Caryophyllaceae Present in Park Uncommon No

Chamaesyce maculata (L.) Small spotted sandmat Euphorbiaceae Present in Park Common No

Chamaesyce maculata auct. non (L.) 

Small = Chamaesyce nutans Euphorbiaceae Present in Park Common No

Chamomilla suaveolens (Pursh) Rydb. = Matricaria discoidea Asteraceae Present in Park Uncommon No

Chenopodium album L. lambsquarters Chenopodiaceae Encroaching NA No

Chenopodium album L. var. striatum

(Krasan) Kartesz, comb. nov. ined. lateflowering goosefoot Chenopodiaceae Encroaching NA No

Chenopodium botrys L. Jerusalem oak 

goosefoot Chenopodiaceae Present in Park Uncommon No

Chenopodium pumilio R. Br. clammy goosefoot Chenopodiaceae Present in Park Rare No
C-3

Species Common name Family Park-Status Abundance Highly invasive

Cichorium intybus L. chicory Asteraceae Unconfirmed NA No

Cirsium vulgare (Savi) Ten. bull thistle Asteraceae Present in Park Uncommon Yes

Convolvulus arvensis L. field bindweed Convolvulaceae Present in Park Rare Yes

Crepis capillaris (L.) Wallr. smooth hawksbeard Asteraceae Present in Park Uncommon No

Crypsis schoenoides (L.) Lam. swamp pricklegrass Poaceae Encroaching NA No

Cytisus scoparius (L.) Link scotchbroom Fabaceae Encroaching NA Yes

Dactylis glomerata L. orchardgrass Poaceae Unconfirmed NA No

Digitalis purpurea L. purple foxglove Scrophulariaceae Encroaching NA No

Elytrigia intermedia ssp. intermedia crested wheatgrass Poaceae Present in Park Uncommon No

Erodium cicutarium (L.) L'Hér. ex Ait. redstem stork's bill Geraniaceae Present in Park Rare No

Erodium cicutarium (L.) L'Hér. ex Ait. 

ssp. jacquinianum (Fisch., C.A. Mey. & 

Avé-Lall.) Briq.

redstem stork's bill Geraniaceae Present in Park Rare No

Festuca pratensis Huds. = Lolium pratense Poaceae Present in Park Uncommon No

Gnaphalium luteoalbum L. = Pseudognaphalium 

luteoalbum Asteraceae Encroaching NA No

Herniaria hirsuta L. ssp. hirsuta hairy rupturewort Caryophyllaceae Encroaching NA No

Hirschfeldia incana (L.) Lagrèze-Fossat shortpod mustard Brassicaceae Encroaching NA Yes

Holcus lanatus L. common velvetgrass Poaceae Present in Park Uncommon No

Hordeum marinum ssp. gussoneanum Mediterranean barley Poaceae Present in Park Rare Yes
C-4

Species Common name Family Park-Status Abundance Highly invasive

Hypericum perforatum L. common St. Johnswort Clusiaceae Present in Park Rare Yes

Koeleria phleoides (Vill.) Pers. = Rostraria cristata Poaceae Unconfirmed NA No

Lactuca serriola L. prickly lettuce Asteraceae Present in Park Uncommon No

Lepidium heterophyllum Benth. purpleanther field 

pepperweed Brassicaceae Present in Park Rare No

Lepidium latifolium tall whitetop Brassicaceae Encroaching NA Yes

Leucanthemum vulgare Lam. oxeye daisy Asteraceae Present in Park Uncommon Yes

Linaria genistifolia (L.) P. Mill. ssp. 

dalmatica (L.) Maire & Petitm.

= Linaria dalmatica

ssp. dalmatica Scrophulariaceae Unconfirmed NA Yes

Lolium multiflorum Lam. = Lolium perenne ssp. 

multiflorum Poaceae Unconfirmed NA No

Lolium perenne L. perennial ryegrass Poaceae Present in Park Uncommon No

Lotus corniculatus L. birdfoot deervetch Fabaceae Encroaching NA No

Lythrum hyssopifolia L. hyssop loosestrife Lythraceae Encroaching NA No

Melilotus alba Medikus white sweetclover Fabaceae Present in Park Uncommon No

Melilotus indica (L.) All. sourclover Fabaceae Present in Park Rare No

Phalaris arundinacea reed canarygrass Poaceae Present in Park Uncommon Yes

Phleum pratense L. timothy Poaceae Present in Park Common No

Plantago lanceolata L. narrowleaf plantain Plantaginaceae Present in Park Uncommon No

Plantago major L. common plantain Plantaginaceae Present in Park Common No

Poa annua L. annual bluegrass Poaceae Present in Park Uncommon No
C-5

Species Common name Family Park-Status Abundance Highly invasive

Poa bulbosa L. bulbous bluegrass Poaceae Present in Park Common No

Poa palustris L. fowl bluegrass Poaceae Present in Park Rare No

Poa pratensis L. ssp. pratensis Kentucky bluegrass Poaceae Present in Park Common No

Polygonum arenastrum Jord. ex Boreau oval-leaf knotweed Polygonaceae Present in Park Uncommon No

Potentilla anglica Laicharding English cinquefoil Rosaceae Unconfirmed NA No

Rumex acetosella L. common sheep sorrel Polygonaceae Present in Park Common No

Rumex crispus L. curly dock Polygonaceae Present in Park Uncommon No

Sisymbrium orientale L. Indian hedgemustard Brassicaceae Encroaching NA No

Solanum sarrachoides auct. non 

Sendtner

= Solanum 

physalifolium Solanaceae Unconfirmed NA No

Sonchus asper ssp. asper spiny sowthistle Asteraceae Present in Park Rare No

Sonchus oleraceus L. common sowthistle Asteraceae Unconfirmed NA No

Spergularia rubra (L.) J.& K. Presl red sandspurry Caryophyllaceae Present in Park Common No

Stellaria media (L.) Vill. common chickweed Caryophyllaceae Encroaching NA No

Taraxacum officinale G.H. Weber ex 

Wiggers common dandelion Asteraceae Present in Park Abundant No

Tragopogon dubius Scop. yellow salsify Asteraceae Present in Park Uncommon No

Trifolium hybridum L. Alsike clover Fabaceae Present in Park Rare No

Trifolium pratense L. red clover Fabaceae Unconfirmed NA No

Trifolium repens L. white clover Fabaceae Present in Park Common No
C-6

Species Common name Family Park-Status Abundance Highly invasive

Verbascum blattaria L. moth mullein Scrophulariaceae Unconfirmed NA No

Verbascum thapsus L. common mullein Scrophulariaceae Present in Park Common Yes

Vicia benghalensis L. reddish tufted vetch Fabaceae Encroaching NA No

Vulpia myuros (L.) K.C. Gmel. var. 

hirsuta Hack. = Vulpia myuros Poaceae Present in Park Uncommon No
C-7

Figure C1. Mapped biophysical classes of Lassen Volcanic National Park (LANDFIRE 2006). Scale: 30 

meters. This map was prepared by other investigators who extrapolated information using Landsat 

Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. The classes in this dataset represent the vegetation that may have been dominant on the 

landscape prior to Euro-American settlement and are based on both the current biophysical environment 

and an approximation of the historical disturbance regime.
C-8

Figure C2. Mapped existing vegetation types in Lassen Volcanic National Park (LANDFIRE 2008). This 

map was prepared by other investigators who extrapolated information using Landsat Thematic Mapper 

and other data. Lands were assigned to map classes by experts in LANDFIRE workshops.
C-9

Figure C3. Mapped existing vegetation in Lassen Volcanic National Park (LANDFIRE 2008). This map 

was prepared by other investigators who extrapolated information using Landsat Thematic Mapper and 

other data. Lands were assigned to map classes by experts in LANDFIRE workshops.
C-10

Figure C4. Mapped environmental site potential of Lassen Volcanic National Park (LANDFIRE 2008). 

This map was prepared by other investigators who extrapolated Landsat Thematic Mapper and other 

data. Lands were assigned to map classes by experts in LANDFIRE workshops. 
C-11

Figure C5. Mapped successional classes in Lassen Volcanic National Park (LANDFIRE 2008). This map 

was prepared by other investigators who extrapolated information using Landsat Thematic Mapper and 

other data. Lands were assigned to map classes by experts in LANDFIRE workshops.
C-12

Figure C6. Mapped existing vegetation height of Lassen Volcanic National Park (LANDFIRE 2008). This 

map was prepared by other investigators who extrapolated information using Landsat Thematic Mapper 

and other data. Lands were assigned to map classes by experts in LANDFIRE workshops.
C-13

Figure C7. Mapped canopy height of Lassen Volcanic National Park (LANDFIRE 2008). This map was 

prepared by other investigators who extrapolated information using Landsat Thematic Mapper and other 

data. Lands were assigned to map classes by experts in LANDFIRE workshops.
C-14

Figure C8. Mapped canopy base height of Lassen Volcanic National Park (LANDFIRE 2007). Scale: 30 

meters. This map was prepared by other investigators who extrapolated information using Landsat 

Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. The map describes the average height from the ground to the bottom of a forest stand's 

canopy; it is the lowest height at which there is a sufficient amount of forest canopy fuel to propagate fire 

vertically into the canopy. There is no universally accepted, empirically-derived definition of canopy base 

height.
C-15

Figure C9. Mapped canopy bulk density of Lassen Volcanic National Park (LANDFIRE 2008). This map 

was prepared by other investigators who extrapolated information using Landsat Thematic Mapper and 

other data. Lands were assigned to map classes by experts in LANDFIRE workshops. 
C-16

Figure C10. Mapped existing vegetation canopy of Lassen Volcanic National Park (LANDFIRE 2007). 

Scale: 30 meters. This map was prepared by other investigators who extrapolated information using 

Landsat Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. 
C-17

Figure C11. Mapped fire regime condition classes of Lassen Volcanic National Park (LANDFIRE 2008). This map was prepared by other 

investigators who extrapolated fuels information using Landsat Thematic Mapper and other data. Lands were assigned to map classes by experts 

in LANDFIRE workshops. The map does not portray fuel, fuel arrangement, or vegetation flammability. The map was based on rough estimates of 

the level to which fire frequencies have departed from “natural” fire frequencies. FRCC is also not a measure of fire risk or hazard. Increasing 

FRCC may lead to either more or less severe fire. Nonetheless, FRCC may be useful to identify where fire should be allowed to burn. The natural 

fire regime of every ecosystem falls into only five classes for determining departure, but the fire regimes of this park do not fit this classification.
C-18

Figure C12. Mapped fire regime groups of Lassen Volcanic National Park (LANDFIRE 2008). This map was prepared by other investigators who 

extrapolated fuels information using Landsat Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. The map does not portray fuel, fuel arrangement, or vegetation flammability.
C-19

Figure C13. Mapped mean fire return interval of Lassen Volcanic National Park (LANDFIRE 2008). This 

map was prepared by other investigators who extrapolated fuels information using Landsat Thematic 

Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE workshops. The 

map does not portray fuel, fuel arrangement, or vegetation flammability.
C-20

Figure C14. Mapped percent of replacement severity fires of Lassen Volcanic National Park (LANDFIRE 

2008). This map was prepared by other investigators who extrapolated fuels information using Landsat 

Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. The map does not portray fuel, fuel arrangement, or vegetation flammability.
C-21

Figure C15. Mapped percent of low severity fires of Lassen Volcanic National Park (LANDFIRE 2008). 

This map was prepared by other investigators who extrapolated fuels information using Landsat Thematic 

Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE workshops. The 

map does not portray fuel, fuel arrangement, or vegetation flammability.
C-22

Figure C16. Mapped departure index of Lassen Volcanic National Park (LANDFIRE 2008). This map was prepared by other investigators who 

extrapolated information using Landsat Thematic Mapper and other data. Lands were assigned to map classes by experts in LANDFIRE 

workshops. 
D-1

Appendix D. Vertebrates of Lassen Volcanic National Park
D-2

Table D1. Bird species of Lassen Volcanic National Park (Burnett and King 2004).

H = historically only. ? = unconfirmed

Species Status Breeds Resident Introduced

Greater White-fronted Goose very rare No No no

Snow Goose rare No No no

Canada Goose common Yes No no

Tundra Swan very rare No No no

Wood Duck uncommon Yes No no

Gadwall very rare No No no

American Wigeon rare No No no

Mallard common Yes No no

Blue-winged Teal very rare No No no

Cinnamon Teal very rare No No no

Northern Shoveler rare No No no

Northern Pintail rare No (H?) No no

Green-winged Teal rare No No no

Canvasback very rare No (H) No no

Redhead very rare No (H) No no

Ring-necked Duck rare Yes No no

Lesser Scaup very rare No No no

Surf Scoter very rare No No no

Bufflehead fairly common Yes No no

Common Goldeneye very rare No No no

Barrow's Goldeneye rare No (H) No no

Common Merganser fairly common Yes No no

Ruddy Duck rare No No no

Ring-necked Pheasant very rare No No Yes

Common Peafowl very rare No No Yes

Ruffed Grouse very rare No? No Yes

Sooty (Blue) Grouse uncommon Yes Yes no

Wild Turkey very rare No No Yes

Mountain Quail uncommon Yes Yes no

California Quail very rare No No no

Pacific Loon very rare No No no

Common Loon rare No (H) No no

Pied-billed Grebe uncommon Yes No no

Eared Grebe rare Yes No no

Western Grebe uncommon No No no

Clark's Grebe rare No No no

American White Pelican very rare No No no

Double-crested Cormorant uncommon No No no

American Bittern very rare No No no
D-3

Species Status Breeds Resident Introduced

Great Blue Heron uncommon No No no

Great Egret very rare No No no

Snowy Egret very rare No (H?) No no

Green Heron very rare No No no

Black-crowned Night-Heron very rare No No no

Turkey Vulture uncommon No No no

California Condor extirpated No (H) No no

Osprey uncommon Yes No no

Bald Eagle fairly common Yes Yes no

Northern Harrier rare No No no

Sharp-shinned Hawk uncommon Yes Yes no

Cooper's Hawk uncommon Yes Yes no

Northern Goshawk uncommon Yes Yes no

Red-shouldered Hawk very rare No No no

Broad-winged Hawk very rare No No no

Swainson's Hawk very rare No No no

Red-tailed Hawk fairly common No? No no

Ferruginous Hawk rare No No no

Rough-legged Hawk very rare No No no

Golden Eagle rare Yes Yes no

American Kestrel uncommon No No no

Merlin rare No No no

Peregrine Falcon uncommon Yes No no

Prairie Falcon rare Yes No no

Virginia Rail very rare No? No no

Sora very rare No? No no

American Coot common Yes No no

Sandhill Crane rare No? No no

Semipalmated Plover very rare No No no

Killdeer uncommon Yes No no

Band-tailed Pigeon uncommon No? No no

Greater Yellowlegs rare No No no

Willet very rare No No no

Spotted Sandpiper common Yes No no

Marbled Godwit very rare No No no

Western Sandpiper uncommon No No no

Least Sandpiper uncommon No No no

Pectoral Sandpiper very rare No No no

Long-billed Dowitcher very rare No No no

Common Snipe fairly common Yes No no

Wilson's Phalarope very rare No No no
D-4

Species Status Breeds Resident Introduced

Red-necked Phalarope very rare No No no

Bonaparte's Gull very rare No No no

Ring-billed Gull very rare No No no

California Gull fairly common No No no

Sabine's Gull very rare No No no

Caspian Tern rare No No no

Forster's Tern very rare No No no

Black Tern very rare No No no

Rock Pigeon uncommon No No no

Mourning Dove uncommon No No no

Barn Owl rare No No no

Western Screech-Owl very rare No No no

Great Horned Owl uncommon Yes Yes no

Northern Pygmy-Owl uncommon Yes Yes no

Spotted Owl uncommon Yes Yes no

Great Gray Owl very rare No No no

Northern Saw-whet Owl uncommon Yes No no

Common Nighthawk common Yes No no

Common Poorwill rare Yes No no

Black Swift very rare No No no

Vaux's Swift fairly common Yes No no

White-throated Swift very rare No No no

Anna's Hummingbird uncommon No No no

Calliope Hummingbird uncommon Yes No no

Rufous Hummingbird common No No no

Allen's Hummingbird very rare No No no

Belted Kingfisher uncommon No? No no

Lewis' Woodpecker rare No No no

Acorn Woodpecker very rare No No no

Williamson's Sapsucker uncommon Yes No no

Red-breasted Sapsucker common Yes Yes no

Downy Woodpecker uncommon Yes Yes no

Hairy Woodpecker common Yes Yes no

White-headed Woodpecker fairly common Yes Yes no

Black-backed Woodpecker fairly common Yes Yes no

Northern Flicker common Yes Yes no

Olive-sided Flycatcher fairly common Yes No no

Western Wood-Pewee common Yes No no

Pileated Woodpecker uncommon Yes Yes no

Willow Flycatcher rare Yes No no

Hammond's Flycatcher fairly common Yes No no
D-5

Species Status Breeds Resident Introduced

Gray Flycatcher rare No No no

Dusky Flycatcher common Yes No no

Pacific-slope Flycatcher rare No No no

Black Phoebe very rare No No no

Say's Phoebe very rare No No no

Ash-throated Flycatcher very rare No No no

Cassin's Vireo fairly common Yes No no

Warbling Vireo common Yes No no

Gray Jay uncommon Yes Yes no

Steller's Jay common Yes Yes no

Western Scrub Jay very rare No No no

Clark's Nutcracker common Yes Yes no

American Crow very rare No No no

Common Raven fairly common Yes Yes no

Horned Lark very rare No No no

Purple Martin very rare No No no

Tree Swallow common Yes No no

Violet-green Swallow rare No No no

Cliff Swallow very rare No No no

Northern Rough-winged Swallow rare No No no

Barn Swallow fairly common Yes No no

Mountain Chickadee common Yes Yes no

Bushtit very rare No No no

Red-breasted Nuthatch common Yes Yes no

White-breasted Nuthatch fairly common Yes Yes no

Pygmy Nuthatch uncommon Yes Yes no

Brown Creeper common Yes Yes no

Rock Wren uncommon Yes No no

Canyon Wren very rare No No no

Bewick's Wren very rare No No no

House Wren uncommon No No no

Winter Wren uncommon Yes No no

Marsh Wren very rare No No no

American Dipper fairly common Yes Yes no

Golden-crowned Kinglet common Yes Yes no

Ruby-crowned Kinglet rare No (H) No no

Blue-gray Gnatcatcher very rare No No no

Western Bluebird rare Yes No no

Mountain Bluebird fairly common Yes No no

Townsend's Solitaire common Yes No no

Swainson's Thrush very rare No (H) No no
D-6

Species Status Breeds Resident Introduced

Hermit Thrush common Yes No no

American Robin common Yes Yes no

Varied Thrush rare No No no

Wrentit very rare No No no

European Starling very rare No No Yes

American Pipit rare No No no

Cedar Waxwing very rare No No no

Orange-crowned Warbler common No? No no

Nashville Warbler fairly common Yes No no

Yellow Warbler uncommon Yes No no

Yellow-rumped Warbler common Yes No no

Black-throated Gray Warbler rare No No no

Townsend's Warbler uncommon No No no

Hermit Warbler common Yes No no

Northern Waterthrush very rare No No no

MacGillivray's Warbler common Yes No no

Common Yellowthroat very rare No No no

Wilson's Warbler common Yes No no

Western Tanager common Yes No no

Green-tailed Towhee uncommon Yes No no

Spotted Towhee rare No No no

Rufous-crowned Sparrow very rare No No no

Chipping Sparrow fairly common Yes No no

Brewer's Sparrow rare Yes No no

Vesper Sparrow rare No? No no

Sage Sparrow very rare No No no

Savannah Sparrow very rare No No no

Fox Sparrow common Yes No no

Song Sparrow common Yes No no

Lincoln's Sparrow fairly common Yes No no

White-crowned Sparrow uncommon Yes No no

Golden-crowned Sparrow uncommon No No no

Dark-eyed Junco common Yes Yes no

Black-headed Grosbeak rare Yes No no

Lazuli Bunting uncommon Yes No no

Bobolink very rare No No no

Red-winged Blackbird common Yes No no

Tricolored Blackbird very rare No No no

Western Meadowlark rare No No no

Yellow-headed Blackbird very rare No No no

Brewer's Blackbird common Yes No no
D-7

Species Status Breeds Resident Introduced

Great-tailed Grackle very rare No No no

Brown-headed Cowbird fairly common Yes No no

Bullock's (Northern) Oriole very rare No No no

Gray-crowned Rosy Finch rare Yes No no

Pine Grosbeak very rare No No no

Purple Finch rare Yes No no

Cassin's Finch common Yes Yes no

House Finch very rare No No no

Red Crossbill fairly common Yes Yes no

Pine Siskin common Yes Yes no

Lesser Goldfinch very rare No No no

American Goldfinch very rare No No no

Evening Grosbeak fairly common Yes Yes no

Table D2. Reptiles of Lassen Volcanic National Park

Common Name Scientific Name

Western Pond Turtle* Clemmys marmorata

Sagebrush Lizard Sceloporus graciosus

Western Fence Lizard Sceloporus occidentalis

Western Whiptail Cnemidophorus tigris

Western Skink Eumeces skiltonianus

Northern Alligator Lizard Elgaria coerulea

Southern Alligator Lizard Elgaria multicarinata

Rubber Boa Charina bottae

Racer Coluber constrictor

Sharp-tailed Snake Contia tenuis

Ring-necked Snake Diadophis punctatus

Common Kingsnake Lampropeltis getula

California Mountain Kingsnake Lampropeltis zonata

Pine Snake Pituophis melanoleucus

Couch's Garter Snake Thamnophis couchii

Western Terrestrial Garter Snake Thamnophis elegans
D-8

Common Name Scientific Name

Common Garter Snake Thamnophis sirtalis

Western Rattlesnake Crotalus viridis

* May be extirpated from the park. Current status of most of these species in the park is unknown.
D-9

Table D3. Amphibians of Lassen Volcanic National Park

Common Name Scientific Name

Rough-skinned Newt Taricha granulosa

California Newt Taricha torosa

Long-toed Salamander Ambystoma macrodactylum

Ensatina Ensatina eschscholtzii

Western Toad Bufo boreas

Pacific Chorus (Tree) Frog Pseudacris regilla

Cascades Frog Rana cascadae

Bullfrog Rana catesbeiana

Table D4. Mammals of Lassen Volcanic National Park. Aside from the bats and some of the small 

mammals, the status of most of these species in the park is unknown.

Common Name Scientific Name

Virginia Opossum Didelphis virginiana

Northern Water Shrew Sorex palustris

Preble's Shrew Sorex preblei

Inyo Shrew Sorex tenellus

Trowbridge's Shrew Sorex trowbridgii

Vagrant Shrew Sorex vagrans

Shrew-Mole Neurotrichus gibbsii

Broad-footed Mole Scapanus latimanus

Big Brown Bat Eptesicus fuscus

Fringed Myotis Myotis thysanodes

Silver-Haired Bat Lasionycteris noctivagans

Hoary Bat Lasiurus cinereus

California Myotis Myotis californicus

Western Small-footed Myotis Myotis ciliolabrum

Long-legged Myotis Myotis volans
D-10

Common Name Scientific Name

Long-eared Myotis Myotis evotis

Little Brown Bat Myotis lucifugus

Yuma Myotis Myotis yumanensis

American Pika Ochotona princeps

Snowshoe Hare Lepus americanus

Mountain (Nuttall's) Cottontail Sylvilagus nuttallii

Mountain Beaver Aplodontia rufa

Northern Flying Squirrel Glaucomys sabrinus

Yellow-bellied Marmot Marmota flaviventris

Western Gray Squirrel Sciurus griseus

California Ground Squirrel Spermophilus beecheyi

Belding's Ground Squirrel Spermophilus beldingi

Golden-mantled Ground Squirrel Spermophilus lateralis

Yellow-pine Chipmunk Tamias amoenus

Merriam's Chipmunk Tamias merriami

Least Chipmunk Tamias minimus

Douglas' Squirrel Tamiasciurus douglasii

Beaver Castor canadensis

Mountain Pocket Gopher Thomomys monticola

Western Red-backed Vole Clethrionomys californicus

Long-tailed Vole Microtus longicaudus

Montane Vole Microtus montanus

Muskrat Ondatra zibethicus

Deer Mouse Peromyscus maniculatus

Bushy-tailed Woodrat Neotoma cinerea

Western Jumping Mouse Zapus princeps

Porcupine Erethizon dorsatum
D-11

Common Name Scientific Name

Coyote Canis latrans

Gray Wolf* Canis lupus

Gray Fox Urocyon cinereoargenteus

Red Fox Vulpes vulpes

Black Bear Ursus americanus

Ringtail Bassariscus astutus

Raccoon Procyon lotor

River Otter Lutra canadensis

Marten Martes americana

Long-tailed Weasel Mustela frenata

Ermine Mustela erminea

Mink Mustela vison

Badger Taxidea taxus

Striped Skunk Mephitis mephitis

Spotted Skunk Spilogale putorius

Mountain Lion Felis concolor

Bobcat Lynx rufus

Pronghorn (Antelope)* Antilocapra americana

Elk (Wapiti)* Cervus elaphus

Mule Deer Odocoileus hemionus

* not resident in the park

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