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The Sierra Forest Voice Newsletter

The Sierra Forest Voice

Web Edition
Vol. 11, No. 2, June 12, 2018


Wood to Energy: Does Forest BIomass Energy Make Sense in the Sierra Nevada?

There is a lot of debate about forest-sourced biomass energy production, especially within the environmental community. Some seem to be categorically opposed to the idea, while others believe there is enough material to support biomass in every forest community with little negative ecological effects. Sierra Forest Legacy is not opposed to biomass, but it must be clearly demonstrated that each biomass facility is in the right place, is the right size, and will be relying on the right woody biomass.

We are not here to debate EPA Administrator Scott Pruitt’s declaration last month that burning wood from forests to produce energy is carbon neutral. It isn't. We are also not here to suggest that sourcing wood from the Sierra Nevada to produce energy is a silver bullet that will reinvigorate local economies and protect communities from wildfire. We are raising this issue because we believe it is possible for forest biomass energy production to be ecologically sustainable, provide public benefits, and help us achieve our goal of increasing the use of ecologically beneficial fire on the landscape.

Being in the right place means that human communities will not experience degraded air quality from facility operation or be adversely affected by diesel truck traffic and exhaust associated with transporting biomass material to the facility. Facilities should also be located close to forested landscapes to reduce transportation costs and diesel emissions. Facilities must be the right size to ensure that energy production does not drive forest management or place ecologically unsustainable pressure on the surrounding forest landscape. The right woody biomass is material generated from forest restoration projects that maintain ecological integrity and species viability, from community fuels reduction projects, or from hazard trees that pose a substantial risk to human life and safety.

Typically, forest restoration projects, community fuels reduction work, and hazard tree removal result in large quantities of non-merchantable biomass that is then piled and eventually burned. For example, the recent tree mortality event in the southern Sierra has inundated communities with extremely large quantities of woody biomass.  Appropriately planned biomass projects provide a public and ecological benefit by producing energy from trees that would otherwise have been piled and burned. Reducing the need to burn piles frees up valuable air quality space for smoke generated from prescribed fire and instead of firefighters spending time burning piles, they can spend their time managing fire for ecological benefits.

For more information on forest biomass energy, we recently drafted this 2-page benefit evaluation guidance document.

Image below: Burn piles in the Lake Tahoe Basin. Removal of this woody biomass to a energy or heat generating facility could increase the use of broadcast burning for greater ecological benefit. Photo credit: Carol Shestak, Matt Busse, USDA Forest Service


Improving Pathways for Determining Smoke Impacts from Wildland Fire

Based on recent research by two top air quality scientists in California, media reports of air quality impacts from wildland fire-related smoke emissions are clouded with significant errors. In a recent report in the Journal Air Quality, Atmosphere and Health researchers Ricardo Cisneros and Donald Schweizer determined that mass media and news reports failed to accurately capture smoke impacts to air quality 68 percent of the time. Public nuisance smoke complaints got it wrong 85 percent of the time.

There are no “bad actors” in the conundrum of the media and air monitoring, just a high degree of mistaken information. The issue of accurate wildland fire smoke monitoring and reporting is complicated by a mix of factors. These are now being addressed in multiple actions, first by Governor Brown’s recent Executive Order and the May revisions to the 2018-2019 California budget; via pending fire bills in the California Legislature, particularly SB 1260 (Jackson); and through collaborations between the Forest Service, CAL FIRE, and other Fire MOU Partners—including Sierra Forest Legacy, the Nature Conservancy, Pacific Forest Trust, the Northern California Prescribed Fire Council, the California Air Pollution Control Officers Association and others.

Three key factors in building increased accuracy in smoke monitoring and reporting are required:  1) the creating of a strategic monitoring network with increased ground level, portable air pollution monitors (E-BAMs) and portable (RAWS) weather stations;  2) Blue Sky modelers skilled in capturing satellite images of smoke plumes—their direction, density and composition; and 3) effective and accurate messaging around fire restoration, smoke impacts and emissions trade-offs, within a strong collaborative communication and public outreach effort.

Figure left: The three "legs" of effective smoke management include accurate air monitoring, modeling, and public messaging. Figure courtesy of Dr. Leland Tarnay, Forest Service Region 5

Strategic Air Quality Monitoring

Ground-level, portable air quality monitors come in many sizes and shapes, but the equipment used to monitor unplanned wildfire events in California is the Environmental Beta Attenuation Monitor (EBAMs). Because of the collaborative work of the Fire MOU Partners and those partners working to expand use of EBAMs for planned events, the Governor’s office and the California Legislature are supporting increased prescribed burning and expanded EBAM deployment to better protect public health with improved smoke monitoring and smoke projections.

EBAm unit for PM 10 and PM2.5 smoke

Image left: Environmental Beta Attenuation Monitor (EBAM) Measuring ground level PM 10 and PM2.5

The additional monitoring tool to join the comprehensive effort to improve certainty pertaining to compliance with prescribed fire prescriptions is the Remotely Activated Weather Station or (RAWS).

This equipment measures fire-related weather information such as fuel moistures, windspeed, and relative humidity for ensuring burn prescription compliance.


Image below: RAWS

Once accurate emissions monitoring (ground level and satellite derived) has occurred, the translation of the data and visuals to the public and media outlets is often complicated by mass media’s inaccurate perceptions, lack of training and lack of understanding of fire’s role on the California landscape. The level of error reported by public media sources in Cisneros and Schweitzer (2018) suggest that it is time to demand science-based smoke monitoring. Fire location, plume location, composition, and direction can accurately predict public health impacts at ground level, coupled with satellite-derived accurate emissions trade-off information that can then be disclosed to the public and media. This applies to events where we are working with fire and have control, and to fire events when we have less control of the outcome. This approach has become our current goal in California.

Monitor locations, distance to fire, monitoring duration, and plume direction matter when measuring particulate matter. For example, in a recent review (Navarro et al. 2018) of nine wildfire studies and seven prescribed fire studies, the PM2.5 concentrations from wildfire smoke were found to be significantly lower than PM2.5 concentrations for prescribed fire smoke. But were these sixteen fires all comparable in terms of area burned and human exposure to smoke? Not so much. First, smoke concentrations and exposure are generally dependent on proximity to source and the location of the monitors related to smoke plumes. The authors reported that the smoke from two recent, large mega-fires, Rim Fire (2013) and the King Fire (2014) in the Sierra Nevada, “largely missed their monitoring site due to smoke plume direction,” citing Burley et al.(2016). The nine monitored wildfire smoke concentration studies were from events with monitor locations ranging from 7 to 242.8 km from the wildfires, while the seven monitored prescribed burn study locations ranged from next to the burn perimeter or 0 km to 80 km distance. Monitoring durations of prescribed fires were also highly variable with short duration monitoring efforts capturing higher emission outputs, while longer duration (24-hour average) reported for wildfires and some prescribed burns showed significantly lower PM2.5 concentrations. The authors also noted that lower intensity prescribed burn smoke plumes, “tend to stay within the canopy, which absorbs some of the pollutants, reducing smoke exposure.”

A recent article in the journal Science of the Total Environment (Fann et al. 2017) reports that estimates of short and long-term exposure and hospital admissions related to wildfire-attributable PM2.5-related premature deaths and respiratory hospital visits (2008-2012) run in the hundreds of billions of dollars annually. It is critically important for policy makers grappling with expanding uncharacteristic wildfires in California—where fire plays a dominant role in shaping vegetation resilience and emissions outcomes—to understand that expanding prescribed fire can contribute in a significant way to both forest resilience and protection of public health by significantly lowering smoke pollution concentrations.

The paper concludes, “Destructive wildfires have higher rates of biomass consumption and have greater potential to expose more people to smoke than prescribed fires.” The authors also discuss the need to better understand the differences in exposures and public health impacts from smoke from prescribed fire compared to wildfire, suggesting that managers “collaborate with air quality departments (internal and external) to monitor PM2.5 concentrations in communities near a prescribed fire.” This is exactly what the collaboration between fire managers and air regulators is shaping up to be in California through the work of the Fire MOU Partners, and State and district air regulators.

Smoke Modeling and the BlueSky Framework 

Smoke modeling combines information about fuel loading, fuel composition, terrain, and related emissions combined with weather forecasting, plume trajectories, smoke composition and dispersion. Fire managers and air regulators need to know a variety of things about potential smoke effects including:

  • What is the maximum smoke concentration that could be expected downwind in areas of concern?
  • When is the smoke likely to arrive at a location?
  • Will the National Ambient Air Quality Standards be exceeded?
  • In what locations should public health alerts potentially be issued?
  • Where will visibility most likely be affected by smoke?
  • What roads are at greatest risk from smoke incursion?
  • What potential actions might be taken (or avoided) to mitigate smoke impacts?

Source: PNW Science Update, Issue 14-Fall 2006

Read more about smoke modeling in support of prescribed fire, prescribed fire’s role in creating resilient landscapes and public understanding and acceptance of smoke.

Improved Communication Around Fire and Smoke

Learning to coexist with wildfire (see Moritz et al. 2014) requires an integrated framework like the Fire MOU Partners are trying to establish today in California. Learning to coexist with wildfire is no easy task given the State’s population of over 40 million people and over 100 years of active suppression of nearly all wildfires, coupled with a very strong public messaging effort to cast all fire as bad. Fortunately, the Forest Service and CAL FIRE, the State fire prevention agency, and the California Legislature are changing their perspectives on fire and its benefits in significant ways. Some of these changes include:

  • The Forest Service fire accomplishments for FY2017 are roughly 100,000 acres of wildland fire managed for resource objectives and 40,000 acres of prescribed fire. Currently the Forest Service in Region 5 is about to surpass last years accomplishments in mid-year 2018;
  • CAL FIRE is significantly expanding their prescribed fire training program and adding over 70 new prescribed fire positions, and making a commitment to prescribe burn 60,000 acres annually in their Vegetation Treatment Program;
  • Increase prescribed fire funding in the State Budget (See May Revised Budget and Senate Budget and Fiscal Subcommittee No.2 (May 17, 2018) and the Governor’s Executive Order B-52-18);
  • Reduce barriers to prescribed burning working with CARB and CALFIRE to speed permitting;
  • Engage University of California Extension, fire safe councils, resource conservation districts, and other entities with demonstrated expertise to increase education and outreach to private landowners regarding prescribed fire, defensible space, fire planning, hardening of structures and more;
  • Increase the number of qualified individuals available to implement prescribed fire projects;
  • Expand funding for California Air Districts to support additional air quality monitoring programs that better protect public health;
  • Limiting liability for prescribed burns;
  • Foster prescribed burns across all ownerships and jurisdictions;
  • CALFIRE Vegetation Treatment Program (when certified) will serve as the programmatic environmental document for prescribed burns initiated by the department or by a certified third party;

The California Legislature is providing important support for expanding the role for prescribed fire in California. Senate Bill 1260 (Jackson) is comprehensive state fire legislation that has taken a broad, scientific examination of the overall problems created by a century of fire suppression and fire exclusion. SB 1260 is moving through the legislative process with broad support. 

Finally, the Fire MOU Partnership Communication and Outreach Plan is helping fire managers talk about fire in a manner that is scientifically defendable and is supportive of expanded fire restoration.


Cisneros, Ricardo and Schweizer, Donald L., 2018. The efficacy of news releases, news reports, and public nuisance complaints for determining smoke impacts to air quality from wildland fire. Air Quality, Atmosphere & Health. May 2018: 11:4

Moritz, M.A., et al. 2014. Learning to Coexist with Wildfire. Nature  doi:10.1038/nature13946

Navarro, K.M., Schweizer, D., Balmes, J.R., and R. Cisneros. 2018. A Review of Community Smoke Exposure from Wildfire Compared to Prescribed Fire in the United States. Atmosphere 2018, 9, 185; doi:10.3390/atmos9050185.

Fann, N., et al 2018. The health impacts and economic value of wildland fire episodes in the U.S.: 2008-2012. Science of the Total Environment 610-611:802-809.

Pacific Northwest Research Station--Science. Update.   A Clear Picture of Smoke: BlueSky Smoke Forecasting. Issue 14, Fall 2006.

Pacific Northwest Research Station—Science Update.  Smoke in a New Era of Fire. Issue 24, Fall 2017

News Bytes from the Front

Please Ask California Senators to Oppose Controversial Farm Bill Forest Attacks

A list of blatantly pro-logging federal forestry provisions have been slipped in to H.R. 2, the Agriculture and Nutrition Act of 2018 (Farm Bill). Please take five minutes to ask California’s Senators to stand up for our National Forests.

On May 18th, the deeply divided U.S. House of Representatives failed to pass the first version of the Farm Bill, which included many of the egregious provisions of the aggressively anti-environment legislation proposed in H.R. 2936, the so-called Resilient Federal Forests Act, and S.B. 2068, the miss-named Wildfire Prevention and Mitigation Act. We covered both bills in-depth in our December 2017 Newsletter. The Farm Bill as proposed includes several new categorical exclusions which would allow logging projects on National Forests up to 6,000 acres in size to escape environmental review. Other provisions would allow logging in Inventoried Roadless Areas while exempting the State of Alaska from the Roadless Rule entirely.

The House is now drafting a new Farm Bill which is scheduled for a vote on June 22nd. For a more thorough analysis of the Forestry Title of the House Farm Bill, see The Wilderness Society’s analysis memo.

The Senate version of the Farm Bill was released last Friday (June 8) and is a vast improvement over the House Bill. The Senate Bill is scheduled for mark up in Committee on June 13th and is expected to be on the Senate floor for a vote prior to the July 4th recess. Please call Senators Feinstein and Harris (contact info below) to ask that they resist efforts to add controversial policies to the forestry title. These controversial policies include:

  • Categorical exclusions that encourage logging without adequate environmental review
  • Attacks on the roadless rule process
  • Eliminating the public's right to seek relief from illegal actions through the courts, and instead limiting citizen relief to a binding arbitration process

Senator Dianne Feinstein’s D.C. Office: (202) 224-3841
Senator Kamala Harris’s D.C. Office: (202) 224-3553


Southern Sierra Roadless Areas Proposal Draws Support from Diverse Partners

Image above: Dinkey Creek in the Bear Mountain RWA (Recommended Wilderness Area). Credit: Steve Evans

This spring, 25 organizations from across California joined Sierra Forest Legacy to support a new proposal to protect the roadless areas in the Sequoia and Sierra National Forests. This proposal grew out of a consensus between Sierra Forest Legacy and our partners that the southern Sierra forests’ revised forest plans should include specific protections for lands identified in their wilderness inventories. In a nutshell, the proposal identifies five priority areas for wilderness recommendation on each forest. For these ten areas, SFL staff members have been working closely with the recreation community to help refine potential wilderness boundaries to avoid conflicts with mountain bike trails and other features not allowed in wilderness areas. In addition to ten wilderness priorities, the 2018 proposal would give some 100 additional areas a “Backcountry Management Area” (BMA) designation that closely mimics the Roadless Areas Conservation Rule’s prohibition on road building in the most pristine areas of the forests.

This new approach has helped broaden the support base for protecting wild places on the Sierra and Sequoia while dampening opposition. We are gratified to see support from new partners including human-powered recreationists, environmental justice advocates, and military veterans. The Forest Service is expected to host some open-house sessions this summer to preview the new draft plans which are tentatively scheduled to be released near the end of 2018, followed by a public comment period. We will continue to keep SFL members informed of opportunities to help protect wild places in the Southern Sierra.

The Southern Sierra Roadless Areas Proposal, including maps and current supporters can be found in our April 9th letter to the Forest Service.


Sierra National Forest Leads the Way: The Forest-wide Prescribed Fire Project

In an era when the need to increase the pace and scale of restoration has never been more acute, landscape restoration of fire is often done in small increments—and not at a scale that can change landscape fire behavior. This is changing.

The Sierra National Forest is proposing to utilize prescribed fire on 10,000 acres per year over the next 15-20 years. The agency has just issued a Scoping Letter on May 14th for a forest-wide environmental analysis of the project, requesting public comments on or before June 15th. Project information—the Scoping Letter and draft Proposed Action—can be found here. (Updated 6-14-18: Read our support letter for the project here).


Conservation and Winter Recreation

2018 will likely be a pivotal year for the Sierra Nevada winter landscape. In times of rising temperatures, changing precipitation patterns, and increased recreational use, six national forests in the Sierra will be the first in the nation to designate which areas of the forests will allow snowmobiles and other motorized over-snow vehicles (OSV) to travel. This process of winter travel planning has huge implications for roadless areas, human-powered recreation, soil compaction, and wildlife such as the Pacific marten and California spotted owl, which are negatively affected by OSV use.

In developing winter travel plans, each forest will undergo a comprehensive planning process under NEPA rules. This will include numerous opportunities for public comment and participation. Informed pro-conservation voices are needed on all forests to speak up for responsible zoning OSV planning that protects wildlife and other sensitive resources. The timeline below shows existing and projected winter travel planning in the Sierra Nevada:

  • Lassen National Forest became the first forest in the nation to finalize a winter travel plan in March 2018. The Forest is now addressing final objections
  • Tahoe National Forest released a draft EIS in April 2018 and accepted comments until May 29. The Tahoe’s draft plan is here. See this interactive map from the Outdoor Alliance for a comparison of alternatives. You can also read WildEarth Guardians and our coalition's comments on the plan here.
  • Eldorado National Forest draft EIS is expected to be released in the summer of 2018, followed by a 45-day comment period
  • Stanislaus National Forest draft EIS is expected to be released in the summer of 2018, followed by a 45-day comment period
  • Plumas National Forest draft EIS is expected in August 2018, followed by a 45-day comment period
  • Lake Tahoe Basin Management Unit is also working on a winter travel plan, but does not have a projected date

Learn more:
Winter Wildlands Alliance, Sierra Nevada planning page
Download “Winter Recreation on National Forest Lands” produced by Winter Wildlands Alliance


SFL Staff with Drip Torches in Hand!

Sierra Forest Legacy staff members Craig Thomas and Ben Solvesky recently attended a prescribed fire workshop at Uc Berkeley's Blodgett Forest Research Station. The "Prescribed Fire on Private Lands" training was conducted by the UC Cooperative Extension and was designed to provide attendees with an understanding of the permitting requirements, legal considerations, burn planning, and burn preparation for implementing prescribed fire on private lands in California.

Attendees also received hands-on experience burning four  acres of the Blodgett Forest. Although putting fire on the ground was a blast, perhaps the most exciting part of the workshop was learning about UC Cooperative Extension’s work to form California’s first Prescribed Burn Association (PBA). A PBA is a group of landowners and other interested citizens that share resources and work together to conduct prescribed burns for resource objectives.

Learm more about the program, and download all the presentations and materials at UC Cooperative Extension forestry here.

Image below: Ben Solvesky and Craig Thomas, Blodgett Forest Research Station, May 2018



Update on the Bi-state Sage Grouse

On May 15, 2018, a U.S. district court federal judge ruled that the U.S. Fish and Wildlife Service acted illegally in 2015 when it reversed its 2013 decision to list the bi-state sage grouse as a threatened species under the Endangered Species Act. The reversal had come after pressure from a coalition of private industry groups and other federal agencies and local agencies (USGS, BLM, Forest Service, and county supervisors) to withdraw the listing decision.   

The USFWS’ actions were declared “arbitrary and capricious” due to a lack of substantial scientific evidence that the voluntary actions proposed to conserve the sage grouse would be effective, either because there was insufficient scientific basis for the efficacy (as in the case of pinyon pine and juniper eradication) or large enough in scope (cheatgrass removal). Further, the court found that the Service’s conclusion that three populations of the sage grouse (White Mountains, Pine Nut, and Mount Grant) were not threatened, and loss of these populations would not be significant, was also not substantiated.   

The lawsuit that brought the issue before the courts was brought by Center for Biological Diversity, Desert Survivors, Western Watersheds Project, and WildEarth Guardians. Congratulations to them and to the many people and organizations that supported this effort.  

Read more about the decision here, and more about the sage grouse in our March 2018 newsletter.


Science in Brief: "Climate Whiplash" -- California's New Normal

Swain, D.L., B. Langenbrunner, J.D. Neelin, and Alex Hall.  2018.  Increasing precipitation volatility in twenty-first-century California.  Nature Climate Change 8:427-433.

Annual precipitation in California is notoriously variable, we seem to either be amid a severe drought or our infrastructure is at a breaking point from torrential rainfall. This is because even a slight change in the jet stream can funnel storms toward or away from California. At no time has the disparity between our precipitation feast or famine been more apparent than over the past 5 years. From 2012-2014 the state experienced what one study found to be the most severe drought in the past 1,200 years (Griffin and Anchukaitis 2014). With another year of lower than average precipitation in 2015, the recent drought triggered a devastating landscape-scale tree mortality event in the southern Sierra Nevada, the likes of which have changed these forests and the communities around them forever. Then, in 2017, it felt like the rain would never stop as the Sierra Nevada experienced one of the wettest water years on record, causing widespread damage to forest roads and the near catastrophic collapse of the Oroville Dam. 

It is not just our imaginations. According to a recently published study on the effects of climate change on precipitation patterns in California, anthropogenic climate change is likely increasing the discrepancy between wet and dry years (aka hydroclimatic extremes) and it is likely going to get worse (Swain et al. 2018). How much worse? Using a set of climate model simulations called the Community Earth System Model Large Ensemble or (CESM-LENS), the researchers were able to predict that California is likely to see a 100–200 percent increase in the frequency of “very wet” rainy seasons (similar to the 2016-2017 water year) by the end of the century. Moreover, the study projects a 300–400 percent increase in the risk of an extraordinary rainfall event by the end of the 21st century, an event consistent with a megaflood that occurred in 1862. Over a 40-day period in 1862, over 100 inches of rain fell on the western slope of the Sierra Nevada. Such an event has been termed  “California’s Other Big One” by the U.S. Geological Survey. What was once a 200-year flood event will be a 40-50-year event, and it is more likely than not that such an event will occur over the next 40 years.

Despite finding that average annual perception in northern California will likely be similar to historical levels, the results of the study suggest that California’s rainy season will be shorter, with longer dry summers and less precipitation in spring and fall. By the end of the 21st century California will experience a 50–150 percent increase in the frequency of very dry years, similar to recent drought years. The projected increases of extended drought coupled with extreme precipitation events are called “precipitation whiplash.” They are driven by increases in greenhouse gas emissions based on a business-as-usual trajectory.

The length of the fire season across the west has been increasing due to rising average temperatures; a longer dry season is likely to amplify this trend, further extending the fire season. Regardless, the combined effects of increasing temperatures, a longer dry season, and more frequent drought years will undoubtedly have pronounced effects on the forests of the Sierra Nevada. 

Other than the obvious solution of curbing global greenhouse gas emissions, we believe that returning frequent and ecologically-beneficial mixed-severity fire to the system is the most appropriate way to increase resilience,  facilitate adaptation to the effects of climate change, and maintain the ecological integrity of our forests.

For a more in-depth discussion on the results of this study, we highly recommend checking out (and bookmarking!) the lead author’s climate blog.

GreatFloodof 1862 Sacramento


Image left: Great Flood of 1862, Sacramento :











Spotlight on Species: Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

“The wild sheep ranks highest among the animal mountaineers of the Sierra. Possessed of keen sight and scent, and strong limbs, he dwells secure amid the loftiest summits, leaping unscathed from crag to crag, up and down the fronts of giddy precipices, crossing foaming torrents and slopes of frozen snow, exposed to the wildest storms, yet maintaining a brave, warm life, and developing from generation to generation in perfect strength and beauty.” —John Muir

Image above: Sierra Nevada bighorn sheep Credit: Steve Yaeger, Sierra Nevada Bighorn Sheep Foundation

The Sierra Nevada bighorn sheep is one of the most iconic mammals in North America, living only in the most rugged mountainous regions of the Sierra Nevada. Seldom seen by any but the most adventurous of visitors to the Range of Light,  many people are little aware of the sheep’s existence, let alone that it is threatened with extinction.

Naturally limited by the harsh terrain in which it lives, the bighorn was likely never very abundant in numbers, and it is estimated that approximately 1,000 of the animals have lived in the Sierra Nevada at any given time historically. The primary reasons for the decline of bighorn sheep have been identified as a combination of disease transmission from domestic sheep, predation by mountain lions, and unregulated hunting. Bighorn sheep have survived in the Sierra Nevada through at least three ice ages, or approximately 300,000 years, after diverging from the desert bighorn sheep approximately 300-400 thousand years ago.

By the 1970s, approximately three remaining Sierra bighorn sheep herds were living at the very highest reaches of their range, along the crest of the mountains in the vicinity of Mt. Whitney on the eastside of the Sierra, above Owens Valley (see historic distribution map). Despite heroic efforts led by Dr. John Wehausen, founder of the Sierra Nevada Bighorn Sheep Foundation, to translocate sheep to reestablish herds in historical locations, the herds continued to decline. By 1995, there were only about 100 sheep left.

In 1999, with a successful petition for emergency listing brought by Wehausen under the federal and state Endangered Species Acts, dedicated funding was secured and the Bighorn Sheep Recovery Program was staffed. In 2007 the Sierra Nevada Bighorn Recovery Plan (PDF) was completed and implementation was underway. The recovery actions include (1) Management of disease risk from domestic sheep, (2) translocations (augmentations and reintroductions) to increase bighorn numbers and their geographic distribution, (3) predator management to limit predation on bighorn sheep, and (4) monitoring and management of genetic variation.

Vigilant monitoring combined with a successful program of capture and translocation has resulted in a mostly steady upward trend for the imperiled species. Failing herds have been bolstered with additions of camptured rams and ewes, and the reintroduction to historical herd areas has also been successful. Captured sheep are ear tagged and fitted with radio telemetry collars, they are given a rapid physical assessment, and genetic data  is being compiled for almost every individual sheep. Genetic data are obtained from fecal samples, blood samples, carcasses, and horns painstakingly gathered for decades, providing a wealth of genetic information that is used to inform current and future translocations in respect to available nutritional sources and threats such as mountain lion predation. The California Department of Fish and Wildlife is the lead agency responsible for managing recovery of the bighorn sheep, but the Bighorn Sheep Recovery Program is an interagency effort with support from US Fish & Wildlife Service, the National Park Service, BLM, US Forest Service, and USDA Wildlife Services.

Critical habitat was designated by US Fish and Wildlife Service in 2008, encompassing 417,577 acres in mountainous regions of Tuolumne, Mono, Fresno, Inyo, and Tulare Counties, California. The recovery area encompasses two national parks (Yosemite and Sequoia-Kings Canyon), four national forests (Inyo, Humboldt-Toiyabe, Sierra, and Sequoia), and lands managed by the Bureau of Land Management. The recovery area is almost entirely federal land and most of it is in federally designated wilderness areas (John Muir, Ansel Adams, Hoover, and Golden Trout). While critical habitat designation does not apply to private land, grazing permits issued by the BLM and Forest Service allow private individuals to graze livestock on publicly owned lands. Thus, designation of critical habitat for endangered species is frequently contested by the ranching/livestock industry. 

Contact between wild bighorn sheep and domestic livestock—particularly domestic sheep—has long been one of the greatest threats to the bighorn’s survival since the arrival of Europeans and their livestock in the Sierras. Transmission of respiratory and other diseases has resulted in mass die-offs of bighorns, who have no immunity to domestic livestock diseases. Domestic sheep, goats, and cattle are also much more destructive to plant resources than the nimble bighorn. In the winter when most of the bighorn herds retreat to lower elevation regions, the likelihood of contact with domestic sheep increases. When coupled with predation from mountain lions and loss of genetic diversity from small population size, the threats from other natural causes (weather, climate, avalanches and other random events) present an increased risk for their survival.

When John Muir first visited the Sierra Nevada, he was shocked by the level of destruction from the “hooved locusts” that were pastured by the millions in the mountains of California. Writing in his journal in the fall of 1873 in the Yosemite region, he wrote: “It is almost impossible to conceive of a devastation more universal than is produced among the plants of the Sierra by sheep. The grass of meadows is eaten close and trodden until it resembles a corral…9/10ths of whole surface of the Sierra is swept by this scourge. Demands legislative interference.”

Figure below: Bighorn Sheep Herd Units and Domestic Sheep Allotments (CDFW 2017).

Domestic sheep allotments near bighorn sheep herd units

Although Muir’s advocacy resulted in establishment and protection of Yosemite National Park in 1890, Muir observed rogue livestock herders who persisted in violating the law and had to be rousted out by Park law enforcement for decades afterwards. The legacy of this flagrantly destructive era lives on today in the story of the Malheur Wildlife Refuge, the Bundy ranch saga, and even in ongoing opposition to restricting domestic sheep grazing. 

Like John Muir, advocates for the bighorn are not going to give up in their battle to save this magnificent animal. After decades of steady effort, many of the high-risk sheep grazing allotments are now vacated (the allotments still exist on paper, but they are not offered up for permits by the federal government). On private land, there are still ranches with sheep and other livestock herds adjacent to or overlapping critical bighorn sheep habitat, but much success has been achieved in reducing the risk on publicly owned lands. Cooperative agreements are sought with ranchers to  encourage improved fencing and timing of grazing to avoid interactions with bighorns.

As a result, some of the herds are now approaching the goals of the recovery plan. As of April, 2016, the total population estimate was 623 bighorns. However, the winter of 2016-17 was a hard winter with record precipitation in some areas of the mountains, and although full population data are not yet complete as of this writing, staff at CDFW estimate that approximately 100 bighorn sheep died in the winter of 2016-2017. This year, 2018, appears to be brighter with fewer losses. A hard winter is usually followed by abundant vegetation in the spring and summer. If a positive trend continues, the species may be “downlisted” within the next decade. Nevertheless, with the spectre of climate change threatening to transform mountain habitats in the Sierra, it isn’t a good time to be an endangered species in the mountain range (see map of current herd distribution).

Habitat and life history

Habitat occurs from the eastern base of the range as low as 4,790 feet to peaks above 14,100 ft . Sierra Nevada bighorn sheep prefer open, rocky areas characterized by steep slopes and canyons that naturally have sparse vegetation where they can see clearly. With keen eyesight, bighorn sheep need to be able to see long distances to escape from predators, especially mountain lions. Fire suppression has been identified as a threat to bighorn because of this, and also because fire is necessary to rejuvenate plants browsed by the sheep. Bighorn sheep are ruminant herbivores, and their diet includes grasses, herbaceous plants, and shrubs. They are very selective feeders and choose the most nutritious forage available. New plant growth is the most nutritious, although this varies by species. Consequently, diet composition varies by season.

Breeding takes place in late fall, generally November and December and most lambs are born in May and June. The lifespan for both Sierra Nevada bighorn sheep males and females has been observed at 8 to 12 years. Adult male rams weight between 120-220 pounds; adult female ewes weight between 110 and 155 pounds. They are five feet long and are approximately 2 ½ to 3 ¼ feet tall at the shoulders. The oldest known ewe documented in the SN lived to be 17 years old, but maximum age is 10-12 years for rams and 12-20 years for ewes.

Both rams and ewes have horns, though the horns of rams are much larger and more curved. The horns of the Sierra Nevada bighorn sheep are more widely spaced than the desert bighorn sheep, whose horns make a tight curl at the ends, while the horns of the Sierra Nevada bighorn continue to flare outwards as they grow.

Rams engage in battles to determine dominance during the breeding (rutting) season. Horn clashes are the most widely known of ram interactions. Rams can be heard for long distances during dominance butting matches. 

Mountain Lion Predation  

In the Sierra Nevada, 96 percent of deaths of bighorns from predation were found to be from mountain lions. In order to avoid predation by mountain lions, some bighorns appear to be abandoning their winter range to remain at high elevation through the winter. This is a strategy that may be lethal during extreme winter conditions. From 1975-2000, at least 54.5 percent of bighorn sheep deaths overall were from mountain lion kills, a rate of loss that could not be sustained as the herds dwindled, necessitating emergency listing and predator control efforts to reduce the lion kills. Today about 200 bighorn are wearing radio telemetry collars, giving good insight into demographic rates. Five mountain lions are currently outfitted with radio collars, and their movements are closely monitored. As a result, over the last year, CDFW biologists know that 11 sheep were killed by mountain lions. Nevertheless, these kills were distributed among several herds, and scientists do not considered this excessive and no mountain lions had to be killed. 

It might be surprising, but support for active monitoring and management of mountain lion predation has come from the Mountain Lion Foundation, a group that initially was opposed to mountain lion control. Predator management is seen today as a temporary measure that will not be necessary when herd units reach a reproductive base of 25 females, except for herd units serving as sources of translocation stock. Biologists familiar with bighorn sheep have independently arrived at a threshold of 25 females as the minimum number for herd viability. 

Viewing Sierra Nevada Bighorn Sheep

CDFW has provided two maps you can use if you’d like to see bighorn sheep in the Sierra. In the winter, with a good pair of binoculars or a spotting scope, you may see bighorn in or around the cliffs of Wheeler Ridge from Pine Creek Road west of Rovana (see map). In the summertime, a good place to look for them is in the Cottonwood Lakes Basin (see map) and Mount Langley area in Sequoia National Park.

Web resources:

Sierra Nevada Bighorn Recovery Plan (PDF).

Federal listing documents, critical habitat, most recent 5 year review (FWS)

Sierra Nevada Bighorn Sheep Foundation

California Department of Fish and WIldlife Sierra Nevada Bighorn Sheep Recovery Program

John Muir writing about bighorn sheep in the Sierra Nevada

Sierra Forest Legacy coalition comments on the draft forest plan revisions for the Inyo, Sequoia, and Sierra National Forests included recommendations to improve protection for SN bighorn sheep. 


October 2014 Talk with Dr. John Wehausen, SN bighorn sheep field researcher. This is from the 2011-2012 Oakland Museum exhibition: A Walk in the Wild: Continuing John Muir's Journey.

2015 video showing capture and translocation of Sierra Nevada bighorn sheep to Yosemite Park

March 2014 Reintroduction discussion with Dr. John Wehausen youtube.




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