Reposted from UC Merced News
Yosemite Valley in the western Sierra Nevada Mountains.
What if nature were to become a polluter, discharging millions of tons of planet-warming carbon into the atmosphere in much the same way as diesel-fueled trucks or coal-fired power plants?
This nature-as-polluter scenario might seem far-fetched, but it's well on its way to becoming reality, according to a recent study co-authored by UC Merced Professor LeRoy Westerling.
In a paper published recently in Scientific Reports Opens a New Window.— “Potential decline in carbon carrying capacity under projected climate-wildfire interactions in the Sierra Nevada” — Westerling and collaborators from the University of New Mexico and Penn State University used three climate models and data from the Intergovernmental Panel on Climate Change to examine how rising global temperatures and increasingly severe wildfires will affect Sierra Nevada forests.
Their conclusion: Changing conditions will turn today's Sierra Nevada forests into tomorrow's greenhouse gas emitters.
“Forests play an important part in regulating the levels of atmospheric carbon,” Westerling explained. “Forests are carbon sinks, essentially giant stockpiles of carbon. Forests are also active carbon consumers. They remove carbon dioxide from the air and convert it into biomass. This traps the carbon, which is no longer free to act as a greenhouse gas in Earth's atmosphere.”
Professor LeRoy Westerling
But projections from Westerling and colleagues suggest that this may change. According to their models, Sierra Nevada forests will experience both a dramatic loss of stored carbon and a substantial decline in their ability to remove CO2 from the atmosphere.
Rising temperatures are creating a warmer, drier Sierra Nevada climate. Westerling previously showed that these changes are leading to dramatic increases in the frequency, size and duration of wildfires. The new study suggests that these same changes will make it harder for forests to regenerate, leading to a loss of forest density, with plants better suited to the new climate eventually replacing trees.
“As trees are displaced, the Sierra Nevada will lose its ability to sequester carbon,” Westerling explained. “The plants that spring up in their place will be significantly smaller, making them less effective carbon sinks than the trees they replaced.”
But the carbon stored in forest trees has to go somewhere.
As trees are burned in more frequent wildfires, and as dead trees undergo decomposition, Westerling and his colleagues predict that as much as 73 percent of the carbon in Sierra Nevada forests will be released, resulting in a dramatic spike in atmospheric carbon. This will transform the Sierra Nevada from a carbon sink into a carbon emitter, making the nature-as-polluter scenario a reality.
Westerling and his collaborators note that their predictions are actually conservative. The effects might be more extreme than their models suggest.
“Our study does not account for a number of factors that might influence the dynamics of forest carbon,” Westerling said. “However, the factors we ignored are likely to accelerate the loss of forest. Our predictions likely underestimate the severity of actual effects.”
Though the predictions are alarming, the authors remain optimistic, hopeful that their findings can contribute to a larger conversation about environmental policy and promote avenues of research that lead to sustainable forest management.
Reposted from the UC Berkeley News
A study led by ecologists at UC Berkeley has found significant flaws in the research used to challenge the U.S. Forest Service plan to restore Sierra Nevada forests to less dense, and less fire-prone, environments.
An example of a mixed-conifer forest in the Sierra de San Pedro Martir National Forest, Baja California Norte, Mexico. This forest experienced active, natural fires until the 1970s. (Photo by Carrie Levine).
Until recently, the consensus among forest ecologists was that before European settlers arrived in the Sierra, the forests were mostly open conifer forests dominated by big trees and low-to-moderately severe fires every eight to 12 years. The Forest Service recently released a plan to restore the range's forests back to this state following decades of fire suppression and timber harvesting regulations, which have created dense, fire-prone forests.
But recent studies, using a newly developed methodology, have argued that the Sierra Nevada was actually a more dense forest than the consensus view. These new studies were used to back a lawsuit to stop the agency's plan to restore Sierra forests following the 2013 Rim Fire. The Berkeley study refutes the conclusions of these studies and identifies flaws in their methods.
“We went through the data and showed that, in every case, this method estimated that the density of trees was two to three times higher than was the reality,” said Carrie Levine, a Ph.D. student of forest ecology at Berkeley and lead author of the study.
The study was recently published online in the journal Ecological Applications. Berkeley professors John Battles and Scott Stephens and research scientist Brandon Collins were co-authors on the publication. Also involved in the study were researchers from Harvard Forest, the USDA Forest Service Pacific Southwest Research Station, the University of Montana, Utah State University, University of California, Davis, and the USDA Forest Service Pacific Southwest Region.
An example of a densified mixed-conifer forest in the Plumas National Forest in Northern California. Fires have been suppressed in this forest for more than 100 years. (Photo by Carrie Levine).
When the U.S. was divvying up land in the West in the late 19th and early 20th centuries, the General Land Office performed surveys so that the land could be parceled and sold. Land was divided into square-mile blocks, with markers used to indicate every corner point. In case a marker was moved, so-called “witness trees” near the stake were identified as reference points. The result of this data is a grid survey of the entire American West.
Using this historic field data, two ecologists at the University of Wyoming, Mark Williams and William Baker, developed a method that claims to calculate the area that a tree occupies, which is then used to calculate a forest's density. This approach is based on the observation that trees create space to keep other trees from cramming next to them, and that this space correlates to a tree's species and size.
To assess the validity of this area-based method of density estimation in the Sierra Nevada, Levine and her co-authors assembled data from plots of mapped trees across the Sierra and Baja California, Mexico. They tested the performance of the area-based method in these mapped stands where the true density was known.
Levine and colleagues found that the area-based method has two basic flaws when applied to the Sierra, the most notable being an inability to actually predict the area that a tree occupies based on its species and size due to a weak relationship between these variables. The other flaw was a failure to account for differences in the number of trees sampled at each corner. The methodological flaws led to an inflated number of trees estimated in a pre-European Sierra Nevada forest, Levine and colleagues argue.
“We have a mapped plot where every tree is measured, so we know the true density,” Levine said.
The study is important not only for the current state of the Sierra Nevada, but for its future.
“As climate changes, we want to have an accurate understanding of the past. This allows us to manage for forests that are resilient to the changes we're expecting in the future,” Levine said.
Reposted from the UCANR Green blog
After conducting extensive forest research and taking into consideration all aspects of forest health – including fire and wildlife behavior, water quality and quantity – a group of distinguished scientists have concluded that enough is now known about proposed U.S. Forest Service landscape management treatments for them to be implemented in Sierra Nevada forests.
Scientists say there is a great need for forest restoration and fire hazard reduction treatments in Sierra Nevada forests.
“There is currently a great need for forest restoration and fire hazard reduction treatments to be implemented at large spatial scales in the Sierra Nevada,” the scientists wrote. “The next one to three decades are a critical period: after this time it may be very difficult to influence the character of Sierra Nevada forests, especially old forest characteristics.”
The scientists' recommendation is in the final report of a unique, 10-year experiment in collaboration: the Sierra Nevada Adaptive Management Project (SNAMP). A 1,000-page final report on the project was submitted to the U.S. Forest Service at the end of 2015. In it, scientists reached 31 points of consensus about managing California forests to reduce wildfire hazards and protect wildlife and human communities.
“SNAMP was founded on a desire to work collaboratively to protect the forests of the Sierra Nevada,” said John Battles, professor of forest ecology in the Department of Environmental Science, Policy and Management at UC Berkeley and SNAMP principle investigator. “The challenges are multifaceted with a huge diversity of perspective among the public, among managers, and among scientists. SNAMP tried to bring all these interests and talents together to safeguard a vital resource and a natural wonder."
SNAMP was created to help develop a collaborative management and monitoring plan consistent with the Sierra Nevada Forest Plan Amendment, signed by regional forester Jack Blackwell on Jan. 21, 2004. The amendment called for the use of fuel reduction treatments – such as prescribed burning, mechanical chopping of underbrush, and harvesting certain trees – in strategically placed areas to slow down potential wildfires and improve forest health.
Because of disagreements over forest treatments in the past, which often led to lawsuits that languished in court for years, the U.S. Forest Service, U.S. Fish and Wildlife Service and the California Natural Resources Agency decided to take a new approach in 2005. They asked the University of California to provide unbiased scientific assessments of the impacts of the proposed treatments. UC was also charged with engaging the public concerned about repercussions of the forest treatments on wildlife habitat and water quality.
The scientific efforts and the forest treatments were all conducted in an open and transparent process. To ensure the greatest number of stakeholders were taking part, SNAMP included a public participation team of social scientists and UC Cooperative Extension outreach professionals to conduct and study the collaboration process.
Susan Kocher, UC Agriculture and Natural Resources Cooperative Extension forestry advisor in the Central Sierra, was a member the project since 2008 and served as the leader of the public participation team during the final two years, succeeding Kimberly Rodrigues, a UC forestry scientist who is now the director of the UC Hopland Research and Extension Center in Mendocino County. Kocher said having outreach and public participation included as a funded part of a science project is unusual.
“We were able to make great strides in getting everybody on the same page,” Kocher said. “That's what our data shows, too.”
A large volume of new scientific information was generated by the science team, and was published in 46 journal articles. The science spread fast and far, according to citation analysis conducted by the public participation team.
“We found that the average time it took for a SNAMP publication to be cited in another journal was about seven months,” Kocher said. “Citations to our articles came from all over the United States and around the globe.”
In addition, SNAMP science-based information was immediately useful to forest managers, according to a 14-page response to the SNAMP final report by the Forest Service, Fish and Wildlife and the California Natural Resources Agency. For example, an excerpt of the response submitted by California Fish and Wildlife noted that “SNAMP proved successful at modifying treatment methodology to meet the ever-changing reality of forest management.”
“The results were able to prove useful for managers past and future regarding how management can be implemented, in the face of wildfires while still retaining important owl nesting/roosting and foraging habitat features in and near owl activity features,” the document said.
SNAMP – funded with $15 million in grants mainly from the U.S. Forest Service, with support from U.S. Fish and Wildlife, California Natural Resources Agency and University of California – ran from 2007 to 2015. The project ended with the submission of the final report that contains details about the study areas, the treatment processes and reports from each of the six science teams. The science teams and their final reports are:
A key chapter in the publication is titled Integrated Management Recommendations. In it, the 31 points of consensus are outlined.
“The integration in this project is also unique,” Kocher said. “Scientists tend to work in their own focus areas, but we can learn a lot from each other's research projects.”
Working together, the scientists looked at all the research outcomes. The first 18 recommendations in the chapter are the direct result of scientific research conducted in SNAMP projects; the remainder of the recommendations are based on other scientific work and research.
Each of the recommendations is linked to a management goal. Some goals may conflict with achieving one or more of the other management goals. This approach to organizing the recommendations was taken to demonstrate that, while many of the management recommendations do not clash, a few may. For example, suggesting treatments across a landscape in a way that minimizes the negative effects on wildlife might reduce the efficiency of treatments aimed at reducing wildfire behavior and impacts.
The next steps are for the U.S. Forest Service to consider and adapt the SNAMP results and recommendations to continue to restore and protect the natural resources at risk in the Sierra.
“My hope is the SNAMP will be seen as a promising first try to apply adaptive management in the Sierra Nevada,” Battles said. “We gained important new insights about the ecology of these forests and we learned how to conduct applied research in an inclusive manner that engages not only scientists from multiple disciplines but also managers and the public."
Reposted from California Magazine
Back when mastodons and giant ground sloths still roamed the earth – the late 70s and early 80s – I worked as a wildfire fighter for the U.S. Forest Service, both on hand crews and engine crews. Our training was narrow but relatively deep. Mainly, we were taught to construct fire lines with hand tools and chain saws. Water, when it was available, generally was used to protect the line and firefighters; seldom was it employed to directly extinguish the flames.
Our basic strategy consisted of digging and cutting line around the flanks of the fire, then burning out fuels to the advancing flames with fusees (devices resembling highway flares) or drip torches. In this way, the “head” of the fire could be steered to natural barriers or areas sufficiently devoid of fuels to make a direct attack possible. We received zero training for structure firefighting. The one time I responded to a burning structure was in Trinity County: A vacation cabin was ablaze due to a faulty propane line. Several engines responded. Federal Forest Service engines are smaller and hold far less water than municipal or state engines, but collectively, we mustered a lot of water on the scene. A direct attack could have been possible, but we knew our training for battling such a fire was inadequate. Instead, we dug a line around the cabin so the flames wouldn't encroach into the surrounding woods, and watched it burn to the ground.
Things are different now. For one thing, wildfires are bigger and more frequent. This is due to drought, climate change, and the sins of past forest managers. In the sixties, seventies and eighties, vast tracts of old growth timber were liquidated in massive clear cuts. These deforested landscapes were replanted as conifer monocrops, resulting in expansive stands of spindly, closely-spaced, second-growth trees that are as flammable as kerosene.
Meanwhile, the goal for wildfire fighters has changed drastically. The emphasis now is on “protecting interface,” which means preventing fires from immolating the homes that have sprouted across the West's woodlands like morel mushrooms after a rain (back when we had rain). This shift has made fighting wildfires far more expensive, more dangerous for firefighters, and has altered priorities from protecting public forests to protecting private assets. Wildfire fighters now receive training in structure fires, but that has diluted, perhaps even vitiated, their original mission. As Berkeley Environmental Science Professor and Wildfire Researcher Scott Stephens noted, more than half the U.S. Forest Service budget for the current fiscal year is dedicated to fire suppression; in the early 1990s, that figure was about 20 percent. Assuming the trend will continue, which seems certain, firefighting could consume 70 percent of the agency's budget by the 2020s.
That means there's less money than ever for restorative work. And this is work that must be done, and soon. Unless we alter the essential characteristics of our coniferous forests, they will quite literally vanish. It's already happening: Stephens observes that significant portions of California's forests are shifting from pine and fir to mixed hardwoods or even grasslands, the result of repeated, high-intensity fires and drought. And once our conifers are gone, we're not getting them back. The change will be permanent.
Even with drought and accelerating climate change, we can still have healthy coniferous forests in the West. But we won't get them by simply letting them grow — and burn (and burn). Stephens observes we need active management: intensive thinning by both mechanical means and prescriptive fire. This will result in forests with fewer but healthier trees, forests that are largely resistant to any but the most catastrophic fires.
A hundred years ago, disastrous wildfires were rare in California. Forests were characterized by widely spaced, extremely large trees; You could ride through them on horseback, unimpeded. Any fires that did ignite generally crept along. They didn't have the “fuel ladders” — dead limbs and needles on the ground, brush and ascending foliage higher up — needed to climb into the crowns of the trees and explode into rolling fireballs. Being large, the trees were thick-barked and resistant to fire. Indeed, periodic low-level fires disposed of deadwood, killed destructive insects, and returned nutrients to the soil as ashes. It was a virtuous cycle, assuring healthy, resilient wild lands that depended on fires, but were not destroyed by them.
That changed with the aggressive fire suppression of the Smokey the Bear era and accelerated clear-cut logging. But as Stephens notes, we can revitalize the “dog hair” (as in, thick as the hair on a dog's back) forests we now have. We can re-create the vibrant, fire-resistant forests of the early 20th century. We know how to do it. We have the tools: chain saws, heavy equipment, and prescriptive fire. It's not that complicated.
But it will take political will and money. It won't require a Manhattan Project-style response —but it'll require one similar to the Civilian Conservation Corps in scope and commitment. We need to put young men and women back into the woods in force, cutting trees and conducting controlled burns. By re-introducing fire into forest ecosystems, we can, paradoxically, protect them from fire. This will entail triage. We'll have to identify those areas that are most vulnerable to fire (e.g., interface communities). The first projects should be shaded fuel breaks, strips of thinned forests around highways and rural towns and residential developments. Following that, more ambitious projects could proceed on larger tracts.
Who pays? The state and feds must contribute, of course. But local communities, commercial timber companies, and private landowners must also cough up. In particular, the counties and interface residents must participate. So far, they've gotten a free ride. County planners have encouraged development in wild-land areas without thought to the implications of wildfire; After all, taxpayers have always picked up fire suppression costs. More suppression costs must be passed on to the counties so they are incentivized to discourage development in our wild lands, and homeowners must pay appropriately heavy premiums if they choose to build in the woods.
Stephens estimates we have about 30 years before it's too — before our coniferous forests are gone forever, replaced with oak woodlands, brush fields, or grassy savannas. And even then, of course, the wildfires will continue. As we saw with the recent Middletown conflagration, hardwood forests and scrublands can burn just as ferociously as conifers. As long as homes intrude into the wild lands, their continued destruction is assured.
We can continue down the current path of increasing fires and escalating suppression costs, or we can invest in forest restoration. The first course is a death spiral. The second will reduce wildfires, preserve the essential character of our wild lands, provide tens of thousands of jobs to young Americans, yield economic benefits ranging from timber production to recreation, stabilize watersheds, and preserve wildlife diversity. Let's just hope we do the right thing.
The 2004 Sierra Nevada Forest Plan Amendment that guides the management of the national forests in the Sierra has been ripe with controversy since its inception. Disagreements over harvesting plan details, the effectiveness of SPLAT fuels treatments and their effects on wildlife and water issues led to the formation of the Sierra Nevada Adaptive Management Project (SNAMP) as a way to address these controversies and learn from the best available science. The US Forest Service, US Fish & Wildlife Service and California Resource agencies contracted with the University of California to be an independent, neutral third party to research key management issues, develop a multi-party adaptive management program that builds on new research and to increase public participation in all aspects of the project. UC scientists are working in five areas: Fire & Forest Ecosystem Health, Water Quality & Quantity, Wildlife (CA Spotted Owl and Pacific Fisher), Spatial, and Public Participation. These teams are conducting scientific research in an open and transparent manner to measure physical and natural processes at relevant management scales, all the while integrating competing public interests, identifying conflicting outcomes and building public trust. The overall goal of this seven year project is to provide the Forest Service and resource agencies with quality information derived from deliberate experimentation that can be used to improve future management decisions and reduce conflict.
SNAMP has two study sites, Last Chance in the northern Sierra and Sugar Pine in the southern Sierra. These sites were selected because they represent the major bio-geographical features of the Sierra Nevada. They have mixed conifer forests with suitable control and treatment watersheds and old forest habitat for species at risk. They are also large enough to support fireshed scale research and active planning by local Forest Service districts for fuels management projects. Two to four years of pre-treatment data has been collected by the UC teams prior to the start of fuels reduction treatments (including thinning, mastication and prescribed fire) that began during summer 2011. Treatments are scheduled for completion by late 2012.
Logs being sorted at the Last Chance thinning project near Foresthill, CA, September 2012.
Photo by Shufei Lei
Analysis of pre-treatment data has led to some initial findings from the various UC science teams. The Forest Team collected data on tree size and species, as well as fuel loading in the study area, then modeled how fire behavior would be affected both before and after the treatment. They predict that both treatments will be effective at moderating wildfire behavior. They also analyzed hundreds of tree core samples and compared growth patterns between live and dead trees. Initial evidence suggests that thinning can improve tree growth even under adverse environmental conditions such as drought.
Dr. John Battles, UC Berkeley forest ecologists shows a SNAMP participant how to read a tree ring core.
Photo by Susie Kocher
The fisher team has used radio collars to track the movements and dispersal of over 66 Pacific fishers in the Sugar Pine area. By retrieving fisher carcasses, the team, in conjunction with UC Davis scientists, has identified the top four causes of fisher mortality in the study site: predation from bobcats, mountain lions and coyotes, disease, rodenticide and road kill. They are currently developing measures of the population dynamics for the species, including reproduction and survival as well as locations of fisher source and sink areas in the study area.
The CA Spotted Owl Team has identified 75 owls in 48 territories within the SNAMP study area. Using data from monitoring territory occupancy and reproductive success of the owls, initial findings suggest that the owl population is in an overall decline. The team is conducting a retrospective analysis on the history of land use and vegetation looking at all observable changes in owl habitat due to disturbance to identify potential causes of decline.
With meteorological and hydrological instruments, the Water Team records and collects data on a daily basis. This data is fed into computer models to produce potential trends in stream discharge and sediment loading or snow accumulation and snowmelt rates. Using different parameters, such as a reduction in leaf area index (LAI), the team is modeling effects of fuels treatments on stream flows and evapo-transpiration rates.
UC Merced graduate student Sarah Martin explaining water team field equipment.
Remote sensing of both study areas was done using Lidar (light detecting and ranging). This data has allowed the Spatial Team to produce many two and three dimensional maps and other products for use by the science teams. Examples include bare earth, slope, aspect and elevation maps; canopy cover and LAI maps; as well as providing information incorporated into fire behavior models. The team has developed methods to detect individual trees from a lidar data point cloud and has used this data to characterize habitat structure for the wildlife teams.
Digital elevation model and vegetation layers Visualization of forest structure developed by the SNAMP
developed by the UC Spatial Team Spatial Team using Lidar data
The role of the Public Participation team is to promote SNAMP through strategic facilitation and outreach and to support the progress of adaptive management. The team reaches many diverse participants through meetings, field trips and workshops; presentations to community leaders and groups; submissions to blogs, industry publications and other media outlets; and the SNAMP website. Current work includes papers on perceptions of forest health, social network analysis and lessons learned through outreach.
SNAMP participants in September 2011 on a field trip to see progress in implementation
of the Last Chance Project near Foresthill. Photo by Shufei Lei.
Funding difficulties affected the scope of the project in 2011. However, the majority of funding has been restored and the project will be completed with a few changes to the original scope of work.
Data collection by these teams will continue for a year after the fuels treatments are complete in order to characterize the effects of the treatments on forest health, fire, water, and wildlife. There will be a final report to agency partners and the public in 2014. For more information, please see the SNAMP website http://snamp.cnr.berkeley.edu/.