Researchers: insects and drought more of a threat to forests than wildfires

custer engine highland fire

Custer FD’s Engine 6 at the Highland Fire west of Custer, SD, July 1, 2012. Photo by Bill Gabbert.

New research shows that the most significant current threat to western dry forests is from insect outbreaks and droughts, not wildfires; and historically abundant small trees offer the greatest hope for forest survival and recovery after these events. Dry forests are low-elevation western forests with tall pines. The study used government records of insect and wildfire damage to compare current threats to dry forests and used records from land surveys conducted in the late-1800s to understand how dry forests persisted for thousands of years in spite of insect outbreaks, droughts, and fires. These forests persisted, this study suggests, by having both young and old trees that together provided bet-hedging.

Data on recent threats to dry forests used government maps of insect outbreaks and wildfires from 1999-2012 across 64 million acres of western dry forests or 80% of the total dry-forest area. “When comparing the rates of insect outbreaks and wildfire over the past fourteen years, we were surprised to discover insect outbreaks impacted 5 to 7 times the area that wildfire did.” said Dr. Mark Williams, a co-author of the study and recent PhD graduate of the University of Wyoming’s Program in Ecology. “In contrast, restoration efforts to increase resilience of dry forests to changing climate focus primarily on threats from wildfire. Our work suggests that impacts from insect pests should be considered with greater weight when formulating restoration prescriptions.”

To understand how forests were resilient to multiple disturbances in the past, the researchers utilized historical data which included 45,171 tree sizes measured along 13,900 section-lines traversed by land surveyors in about 4.2 million acres of dry forests in Arizona, California, Colorado, and Oregon in the late-1800s.

“The late-1800s land surveys provide us with a spatially extensive and detailed view of how these dry forests persisted through unpredictable episodes of insect outbreaks, droughts, and wildfires” said Dr. William Baker, a co-author of the study and Professor Emeritus in the Program in Ecology and Department of Geography at the University of Wyoming. “What we see from the surveys is that dry forests historically had many large trees, that often survived wildfires, but even more small trees that were less prone to be killed during insect outbreaks and droughts. The combination of abundant youth and older trees provided bet-hedging insurance that allowed these forests to survive and recover regardless of whether an insect outbreak, drought, or wildfire occurred. These unpredictable events may increase with global warming.”

The study’s findings suggest current programs that remove most small trees to lower the intensity of wildfires in dry forests and restore large trees lost to logging, may reduce forest resilience to the larger threats from insect outbreaks and droughts. “Using historical forests as a guide, our study suggests we may want to modify our restoration and management programs so they do not put all our eggs in one basket, but instead hedge our bets by keeping both large trees and abundant small ones” said Dr. Baker.

Key findings:

  • Over the last fourteen years, insect outbreaks have impacted 5 to 7 times more dry forests than have wildfires.
  • Historically, dry forests had large trees, but were numerically dominated by small trees, 52-92% of total trees.
  • The variable structure of past forests provided bet-hedging insurance against multiple disturbances and continued persistence. Removing most small trees for modern restoration treatments may reduce the resilience of these forests.

The study was published Open Access online in the international scientific journal, Frontiers in Ecology and Evolution and is freely available to download on their website.

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New research outlines global threat of smoldering peat fires

peat fire

A smoldering peatland fire in shown in a drained lakebed in Florida, where the fire smoldered for months and consumed several feet of organic soil in some places. Credit: Desert Research Institute, the environmental research arm of the Nevada System of Higher Education.

“The scary thing is future climate change may … dry out peatlands. If peatlands become more vulnerable to fire worldwide, this will exacerbate climate change in an unending loop.”  Guido R. van der Werf

Six researchers have written a paper about how climate change is expected to increase the number of peat fires worldwide. This is disturbing for a number of reasons, including the health effects of the additional smoke that humans must breathe, and the additional carbon in the atmosphere may “exacerbate climate change in an unending loop.”

The researchers — Merritt R. Turetsky, Brian Benscoter, Susan Page, Guillermo Rein, Guido R. van der Werf, and Adam Watts — all work for universities. Even though the funding was supplied by five government agencies, if you want to read their paper at Nature Geoscience it will cost you between $5 and $32. Open Access is apparently not a priority for the universities and government agencies that are responsible for this important taxpayer funded research. The agencies that funded the research, other than the universities that employ the scientists, are National Science Foundation (NSF), NASA, The European Research Council, the Natural Sciences and Engineering Research Council of Canada, and the Desert Research Institute’s Division of Atmospheric Sciences (the environmental research arm of the Nevada System of Higher Education).

Government agencies should not fund research unless there is a guarantee that the results will be immediately, freely, and easily available on the internet.

Below is an article about their findings, supplied by the Desert Research Institute, the environmental research arm of the Nevada System of Higher Education, the employer of Mr. Watts.

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The natural disaster plays out like a movie script – ash falling from the sky, thick smoke shutting down airports and businesses across the globe, and uncontrollable fires burning for days and weeks. But this is not from a script; rather, it is a vivid description of a future climate change scenario in which the Earth’s peat-rich regions become more susceptible to drying and burning.

New research published this week in the journal Nature Geoscience, co-authored by Adam Watts, a fire ecologist at Nevada’s Desert Research Institute (DRI) and deputy director of DRI’s Climate, Ecosystems, Fire and Applications Program, outlines the threat of drying peatlands (also known as mires) across the globe and their increased vulnerability to fire and carbon loss.

Peatlands – which make up around three-percent of the Earth’s land surface and store approximately 25-percent of the world’s soil carbon – are deposits of plant material and organic matter mixed with soil that is too wet to support high levels of decomposition. Peatlands are found on all seven continents.

Already the largest fires on Earth in terms of their carbon footprint, these smoldering fires burn through thick layers of peat, built up over thousands of years, which blanket the ground in ecosystems ranging from the tropics to the arctic.

“When people picture a forest fire, they probably think of flames licking up into tree tops, and animals trying to escape,” said the study’s lead author Merritt Turetsky, a professor of Integrative Biology at University of Guelph in Ontario, Canada. “But peat fires tend to be creeping ground fires. They can burn for days and weeks, even under relatively wet conditions. They lack the drama of flames, but they produce a lot of smoke.”

That smoke contains large amounts of carbon and makes peat fires dangerous to human health. It can worsen air quality and even trigger asthma and other respiratory problems.

“In addition to the amount of carbon released, the types of emissions also can make smoldering fires of greater concern than fires where most of the combustion takes place in flames,” said Watts, who is studying the emissions from burning peat and many other types of organic fuels with his DRI colleagues to determine their potential effects in the atmosphere and on our global climate.

“Peat fires are an example of wildfires having effects far beyond the areas where they occur, and these effects can last for a very long time,” he added.

Turetsky and former University of Guelph post-doctoral researcher Brian Benscoter teamed up with temperate and tropical fire scientists to summarize what is known about peat fires, from massive lightning-ignited fires that burn large areas of the boreal region to tropical fires often triggered by human activity.

“The tropical peatlands in Southeast Asia are a clear demonstration of how human activity can alter the natural relationships between ecosystems and fire,” explained Susan Page, a University of Leicester professor and co-author on the study. “Tropical peatlands are highly resistant to natural fires, but in recent decades, humans have drained peatlands for plantation agriculture. People cause the deep layers of peat to dry out, and also greatly increase the number of fire ignitions. It’s a double threat.”

This causes a host of problems, including health issues, airport and school closures, and political tensions.

The paper concludes that almost all peat-rich regions will become more susceptible to drying and burning with a changing climate. The authors also note that the ecology of peat fires and the role of peat fires in long-term Earth system processes need to be explored more thoroughly in future research.

“Thanks to satellite data, we are fully aware of the vast scale of burning in drained peatlands, mostly in Indonesia,” said co-author Guido van der Werf, a professor at Amsterdam’s VU University. “The scary thing,” Werf added,” is future climate change may actually do the same thing: dry out peatlands. If peatlands become more vulnerable to fire worldwide, this will exacerbate climate change in an unending loop.”

This research was supported by the National Science Foundation (NSF), NASA, The European Research Council, the Natural Sciences and Engineering Research Council of Canada, and the Desert Research Institute’s Division of Atmospheric Sciences.

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Wildfire briefing, December 4, 2014

Fires in U.S. and Australia determined to be caused by power lines

Map of Pfeiffer Fire

Map of Pfeiffer Fire at Big Sur, California, looking northwest, showing the fire perimeter at 10:34 p.m. PST, December 18, 2013. (Click to enlarge)

Two fires, in Western Australia and California, have recently been determined to be caused by electrical power lines.

The Pfeiffer Fire at Big Sur, California started on December 16, 2013 and burned 34 homes and 917 acres in the coastal community 23 miles south of Monterey. The U.S. Forest Service reported on Wednesday:

The cause of the fire was determined to be high resistance heating of the Pfeiffer Ridge Mutual Water Company electrical control wires immediately adjacent to a steel water pipe line. The high resistance heating of the electrical control wires created a competent ignition source for this fire. The first fuel ignited was accumulated dried leaves and redwood needles.

The other fire was in Western Australia. Below is an excerpt from an article in Western Australia Today:

A rotted power pole infested with termites has been blamed for the Parkerville bushfire which destroyed more than 40 homes this year. But EnergySafety director Ken Bowron said the organisation would not take action against Western Power or the landowner.

The EnergySafety report into the cause of the fire on January 12 was released on Thursday and found the bushfire originated from a private pole at 180 Granite Road, Parkerville.

“There was no evidence to suggest the work performed by Western Power to replace the surface aerial seven months before the incident, or the work to replace the adjacent pole two day before the bushfires, causes the PA pole to fail,” Mr Bowron said.

“Based on the available evidence and legal advice, EnergySafety will not be taking any legal action against any party. The clear finding of the report is that the pole failed because it was rotten and had been infested by termites.

Hearing in Prescott on Granite Mountain Hotshots’ retroactive retirement benefits

From the Daily Courier in Prescott, Arizona:

Now nearly a year and a half after 19 Granite Mountain Hotshots died fighting the Yarnell Hill wildfire, the matter of retroactive retirement benefits continues to play out at Prescott City Hall.

With its earlier decision granting retirement benefits to the family of fallen Hotshot Andrew Ashcraft still under appeal, the local fire retirement board will take on two new retirement cases today.

During a 9 a.m. Thursday hearing at Prescott City Hall, the Prescott Board of the Public Safety Personnel Retirement System Board will turn to the retirement claims by the families of Sean Misner and William Warneke, and whether the scope of the actual hearings on the claims should be limited…

Tree ring researcher at the University of Arizona honored

Thomas Swetnam

Thomas W. Swetnam with tree-ring specimens in the UA’s Laboratory of Tree-Ring Research. (Photo courtesy of Michaela Kane/Arizona Daily Wildcat)

Thomas W. Swetnam, Regents’ Professor of dendrochronology and director of the University of Arizona Laboratory of Tree-Ring Research, has been named a Fellow of the American Association for the Advancement of Science (AAAS), the world’s largest general scientific society.

As part of the Section on Geology and Geography, Swetnam was elected as an AAAS Fellow for his investigations of tree rings as a record of past changes in climate, allowing scientists to predict future forest-fire frequencies in the Southwest.

Mr. Swetnam specializes in analyzing climate changes through history and prehistory, dangerous insect outbreaks and forest fires. In recent years, enormous blazes, some 10 times greater than those that firefighters have been accustomed to seeing in California and Arizona, have forced scholars to attempt to understand this phenomenon. The conclusions from Swetnam’s studies of these so-called megafires and their alarming size, duration and frequency have made the scientific community, governments throughout the world and media to pay close attention. Swetnam has appeared on programs such as PBS’ “NewsHour” and CBS’ “60 Minutes.”

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Animated fire history for Yosemite National Park

Kate Wilkin describes this video that illustrates the fire history in Yosemite National Park in Southern California:

Once fire is restored as an ecosystem process, fires often fit together like a jig saw puzzle or overlap slightly. Where fires overlap, they sometimes moderate how many trees are killed by the fire. However, if a fire kills most trees, then following fires continue to kill many trees. These findings are from the Wildland Fire Use program, such as in
Yosemite National Park’s upper mixed conifer forests in the Illilouette Creek Basin—a nearly 50 year experiment allowing 150+ lightning strike fires to burn in Yosemite’s wilderness. Here, the fire frequency and effects are approaching historical forest conditions. These results, which reduce fire hazards for people and nature, could be seen in similar forests elsewhere in California if fire became a principle tool of forest management.

Video by Kate Wilkin and Shannon Fairchild from the Stephens Wildland Fire Science Lab at the University of California at at Berkeley. The map is projected in UTM 11N NAD 83. Fire history polygons from Yosemite National park.

Ms. Wilkin is a graduate student at Berkeley’s Department of Environmental Science, Policy, and Management. She elaborates on her work HERE.

In 2015 Yosemite National Park celebrates their 150th year.

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Researchers recommend amount of fire clearance around structures

Researchers have concluded that the most effective fire clearance or defensible space around structures, to reduce the chances of them burning in a wildfire, is between 16 and 58 feet.

Below is an excerpt from the abstract of a paper written by Alexandra D. Syphard, Teresa J. Brennan, and Jon E. Keeley, submitted to a journal September 16, 2014.

We analysed the role of defensible space by mapping and measuring a suite of variables on modern pre-fire aerial photography for 1000 destroyed and 1000 surviving structures for all fires where homes burned from 2001 to 2010 in San Diego County, CA, USA. Structures were more likely to survive a fire with defensible space immediately adjacent to them. The most effective treatment distance varied between 5 and 20 m (16–58 ft) from the structure, but distances larger than 30 m (100 ft) did not provide additional protection, even for structures located on steep slopes.

Two of the three authors are public employees, so the taxpayers already paid for this research. However, if you want a copy of The role of defensible space for residential structure protection during wildfires, it will cost you $25.

More about Open Access to research that is paid for by taxpayers.

 

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