Posts Tagged: wildfire
Climate change pushes West into a fire-prone future
A paper that examined climate change's likely effects on global fire patterns predicts the West will see more wildfire, said an article by Bettina Boxall in the Los Angeles Times.
The lead author of the paper, published Tuesday in the journal Ecosphere, was Max Moritz, UC Cooperative Extension specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. Moritz, a wildfire expert, and his colleagues concluded that by the end of the century, much of the world will experience more wildfire than it does now.
Rising temperatures lengthen the fire season and dry out vegetation, making it more flammable. More rain could increase plant growth, producing more fuel to burn. In other areas, climate change may reduce fire. More rain in the tropics could decrease fire; less rain in other areas may reduce fuel levels and stunt plant growth, cutting the fire potential.
“Fire is not going anywhere,” Moritz said. The study results, he said, emphasize the need “to rethink how we live with fire and take it more seriously.”
Climate change likely means more fire for the West.
Climate change will alter risk of wildfire worldwide
By the end of the century, almost all of North America and most of Europe is projected to see a jump in the frequency of wildfires, primarily because of increasing temperature trends. At the same time, fire activity could actually decrease around equatorial regions, particularly among the tropical rainforests, because of increased rainfall.
The study, to be published Tuesday, June 12, in Ecosphere, an open-access, peer-reviewed journal of the Ecological Society of America, used 16 different climate change models to generate what the researchers said is one of the most comprehensive projections to date of how climate change might affect global fire patterns.
"In the long run, we found what most fear — increasing fire activity across large parts of the planet," said study lead author Max Moritz, fire specialist in UC Cooperative Extension. "But the speed and extent to which some of these changes may happen is surprising."
"These abrupt changes in fire patterns not only affect people's livelihoods," Moritz added, "but they add stress to native plants and animals that are already struggling to adapt to habitat loss."
The projections emphasize how important it is for experts in conservation and urban development to include fire in long-term planning and risk analysis, added Moritz, who is based at UC Berkeley’s College of Natural Resources.
UC Berkeley researchers worked with an atmospheric scientist from Texas Tech University to combine over a decade of satellite-based fire records with historical climate observations and model simulations of future change. The authors documented gradients between fire-prone and fire-free areas of Earth, and quantified the environmental factors responsible for these patterns. They then used these relationships to simulate how future climate change would drive future fire activity through the coming century as projected by a range of global climate models.
"Most of the previous wildfire projection studies focused on specific regions of the world, or relied upon only a handful of climate models," said study co-author Katharine Hayhoe, associate professor and director of the Climate Science Center at Texas Tech University. "Our study is unique in that we build a forecast for fire based upon consistent projections across 16 different climate models combined with satellite data, which gives a global perspective on recent fire patterns and their relationship to climate."
The fire models in this study are based on climate averages that include mean annual precipitation and mean temperature of the warmest month. These variables tend to control long-term biomass productivity and how flammable that fuel can get during the fire season, the researchers said.
Variables that reflect more ephemeral fluctuations in climate, such as annual rainfall shifts due to El Niño cycles, were not included because they vary over shorter periods of time, and future climate projections are only considered representative for averages over time periods of 20-30 years or longer, the authors said.
The study found that the greatest disagreements among models occur for the next few decades, with uncertainty across more than half the planet about whether fire activity will increase or decrease. However, some areas of the world, such as the western United States, show a high level of agreement in climate models both near-term and long-term, resulting in a stronger conclusion that those regions should brace themselves for more fire.
"When many different models paint the same picture, that gives us confidence that the results of our study reflect a robust fire frequency projection for that region," said Hayhoe. "What is clear is that the choices we are making as a society right now and in the next few decades will determine what Earth’s climate will look like over this century and beyond."
Study co-author David Ganz, who was director of forest carbon science at The Nature Conservancy at the time of the study, noted the significance of the findings for populations that rely upon fire-sensitive ecosystems.
"In Southeast Asia alone, there are millions of people that depend on forested ecosystems for their livelihoods," he said. "Knowing how climate and fire interact are important factors that one needs to consider when managing landscapes to maintain these ecosystem goods and services."
The researchers noted that the models they developed focused on fire frequencies, and that linking these to other models of fire intensity and vegetation change are important next steps.
"Our ability to model fire activity is improving," said Moritz, "but a more basic challenge is learning to coexist with fire itself."
The Natural Sciences and Engineering Research Council of Canada, the U.S. Forest Service, the National Science Foundation and The Nature Conservancy helped support this study.
RELATED INFORMATION
- Climate change to spur rapid shifts in fire hotspots, projects new analysis (2009 UC Berkeley press release)
Let it burn: Prescribed fires pose little danger to forest ecology
The paper, published in the June issue of the peer-reviewed journal BioScience, and led by researchers at the University of California, Berkeley, synthesizes 20 years of research throughout the country on the ecological impact of reducing forest wildfire risk through controlled burns and tree thinning. It comes as California braces for a potentially bad fire season, particularly in the southern Sierra where precipitation was half its normal level.
"We need to act, because climate change is making fire season longer, temperatures are going up, and that means more fire in many regions, particularly ones with a Mediterranean environment," said study lead author Scott Stephens, UC Berkeley associate professor of fire science.
The study authors, which included scientists from the U.S. Forest Service and six research universities in the United States and Australia, relied upon data from the U.S. Fire and Fire Surrogates Study, in addition to a wide range of other studies. Together, the studies represented a broad spectrum of ecological markers, detailing the effects of fuel-reduction treatments on wildlife, vegetation, bark beetles, soil properties and carbon sequestration.
"Some question if these fuel-reduction treatments are causing substantial harm, and this paper says no," said Stephens. "The few effects we did see were usually transient. Based upon what we've found, forest managers can increase the scale and pace of necessary fuels treatments without worrying about unintended ecological consequences."
A few of the researchers’ specific ecological findings include:
- For the first five years after treatment, some birds and small mammals that prefer shady, dense habitat moved out of treated areas, while others that prefer more open environments thrived. The study authors said these changes were minor and acceptable.
- When mechanical tree thinning was followed by prescribed fire, there was an increase in the overall diversity of vegetation. However, this also included non-native plant species. The researchers recommend continued monitoring of this effect.
- Only 2 percent or less of the forest floor saw an increase in mineral soil exposure, which could lead to small-scale erosion. Other soil variables, such as the level of compaction, soil nitrogen and pH levels, were temporary, returning to pre-treatment levels after a year or two.
- Increases in bark beetles, a pest that preys on fire-damaged trees, was short-lived and concentrated in the smaller diameter trees. Researchers noted that thinning out a too-dense forest stand improves tree vigor and ultimately increases its resilience to pests, in addition to fire.
The results of this paper may help inform an analysis of one of the larger prescribed fires in the history of the U.S. Forest Service. Called the Boulder Burn, the proposed treatment covers 6,000-9,000 acres in the Southern Sierra Nevada's Sequoia National Forest and is tentatively set to begin by late fall.
"This paper is more comprehensive and definitive than any other article I've seen," said Malcolm North, research scientist with the U.S. Forest Service and an associate professor in forest ecology at UC Davis. "In one place, it summarizes the state of the science in fuel-reduction treatments, and to my mind, it shuts the door on those who say that any type of fuels treatment is detrimental to the forest. If done properly where surface fuels are reduced, treatments work. It's time to get on with it."
Nearly a century of fire suppression and the preferential logging of large-diameter trees, which are better able to withstand forest fires, have left forests vulnerable to more destructive, albeit less frequent, wildfires, the researchers said. In addition, the lack of fire has hindered nutrient cycling in forests and the proliferation of certain plant species, such as the sequoia, that rely upon fire to promote seed dispersal.
This realization led to the gradual re-emergence during the past 20 years of fuel-reduction as a forest management tool. The goal is simple: Thin or remove overly dense stands of trees, ground vegetation and downed woody debris in a carefully controlled way before they become fuel for a raging wildfire. When low- or moderate-intensity controlled burns are not an option, fire-prone trees are mechanically removed or shredded on site.
Such techniques are an attempt to emulate the frequent fires common in California for thousands of years. Before 1800, Stephens said, an estimated 1.1 million acres of forest burned annually in California, including wildfires ignited by lightning and other natural sources, and blazes set intentionally by Native Americans as a way to manage or alter landscapes. Most were blazes of low-to-moderate intensity that more than 80 percent of the trees could survive, unlike the catastrophic wildfires of modern times.
"Today, the combination of wildfires and fuel-reducing treatments only touch 6-8 percent of the land that used to burn annually before 1800, and fuel-reducing treatments alone only affect 1 percent," said Stephens. "That's a pittance. At that level, treatments are just triage rather than fire prevention."
To approach levels that have a chance of reducing wildfire risk in the long term, he said, the amount of land to be treated in a year would need to increase to 2-4 percent — still low compared to historical levels.
Stephens noted that two-thirds of the fuel-reduction treatments in the western United States rely upon mechanical thinning, which would be much more costly than prescribed burns to scale up. In the southeast region, the use of prescribed fire dominates.
In the West, particularly in California, the biggest challenge to expanding controlled burns is the potential reduction in air quality during treatment, said Stephens.
"We have a choice," he said, "of dealing with lower levels of smoke from prescribed fires that may only be needed every 15 years or so, and which can be timed for optimum wind conditions, or acute levels of smoke from catastrophic fires that can last for months when they hit."
The U.S. Department of Agriculture-U.S. Department of the Interior Joint Fire Science Program helped support this research.
UCCE supports Tahoe fire awareness week and Oroville nutrition decathlon
“With 2012 shaping up to be a high risk year for wildfires, the more people can prepare to survive the threat the better we all will be,” said Susan Kocher, University of California Cooperative Extension advisor, natural resources.
Kocher speaks in session three of the seminar series on May 30 about defensible space landscaping. The session also includes a talk by Wendy West, UC Cooperative Extension program representative, natural resources, titled "Learning how to garden at Lake Tahoe."
See the UCCE Lake Tahoe Basin Wildfire Awareness Week website for more details and links to the webinars.
Nutrition Decathlon
UC Cooperative Extension in Butte County offers local schools a "Nutrition Decathlon," a full-day nutrition and physical activity program, reported the Oroville Mercury-Register.
UCCE is beginning its Nutrition Decathlon season, hosting activities at schools that are making changes on their campuses, said Jona Pressman, UCCE program manager, nutrition.
"To participate, they need to be making significant changes with physical activity and nutrition," Pressman said.
At Helen Wilcox School last Friday, students ran, jumped, balanced on beams, tossed balls into nets, hopped in sacks, ducked through hoops, balanced bean bags on their heads, crawled through tubes, did pushups and lifted slight weights, reported Barbara Arrigoni, Mercury-Register staff writer.
Sudden oak death may increase wildfire fuel
Research by UC Cooperative Extension staff in Humboldt County shows that infection and oak mortality are only the beginning of the story, as the disease may increase forest fuels and put infested stands at higher risk of severe wildfire.
UC Cooperative Extension forest advisor Yana Valachovic, with assistance from Humboldt State University’s Forestry Department and CAL FIRE, found that in Douglas-fir-tanoak forests where high hardwood mortality is related to SOD, fuels can build up to hazardous levels on the forest floor over time. Their research documented fuels buildups in infected areas that could increase a wildfire’s flame length by 3 to 4 feet and double a wildfire’s rate of spread, depending on how much time has elapsed since initial infection.
Likewise, the increased fuels on the forest floor can take a long time to break down, posing a long-term fire hazard and additional risks to firefighters.
“The disease creates a hazardous fuels situation that is passed on to firefighters during wildfire," says Valachovic. "They must combat blazing downed trees, patches of increased winds and fire behavior, and other physical and logistical obstacles.”
Hugh Scanlon, chief of CAL FIRE's Alder Conservation Camp, helped co-author the recent paper with Valachovic and others.
"In many cases, modeled wildfire conditions in sudden oak death affected forests exceed safety thresholds for handcrews, calling for changing suppression tactics and strategies," Scanlon says. "This can mean more heavy equipment, aircraft use, indirect lines and more area burned with higher intensity.”
Sudden oak death is still a relatively new disease in California, and the long-term ecological consequences of SOD infection and spread are largely unknown. However, this research shows that fuels are one of the major issues associated with the disease, and will require increased attention and management in coming years. For more information about this study, see the full paper, which was published in the journal Forest Ecology and Management (http://www.sciencedirect.com/science/article/pii/S0378112711001228.
To see a map showing the locations of sudden oak death in California, go to http://www.oakmapper.org/. At the website, you can also download the Oakmapper iPhone app to help UC scientists monitor the disease by reporting suspected cases of sudden oak death.