More science indicates pine beetle outbreaks do not lead to catastrophic fire

mountain pine beetle

Mountain pine beetle

Scientists continue to develop evidence showing that pine beetle outbreaks do not lead to catastrophic wildfires. This should not be a shocking development to those who have been keeping abreast of the studies on the subject, including one that Wildfire Today first covered in 2010 (Firefighters should calm down about beetle-killed forests).

In a soon to be published paper, University of Colorado Boulder researcher Sarah Hart determined, “The bottom line is that forests infested by the mountain pine beetle are not more likely to burn at a regional scale. We found that alterations in the forest infested by the mountain pine beetle are not as important in fires as overriding drivers like climate and topography.”

The CU-Boulder study authors looked at the three peak years of Western wildfires since 2002, using maps produced by federal land management agencies. The researchers superimposed maps of areas burned in the West in 2006, 2007 and 2012 on maps of areas identified as infested by mountain pine beetles.

Western U.S. forests killed by the mountain pine beetle epidemic are no more at risk to burn than healthy Western forests, she found. Results that fly in the face of both public perception and policy.

The area of forests burned during those three years combined were responsible for 46 percent of the total area burned in the West from 2002 to 2013.

Co-authors on the new study include CU-Boulder Research Scientist Tania Schoennagel of the Institute of Arctic and Alpine Research, CU-Boulder geography Professor Thomas Veblen and CU-Boulder doctoral student Teresa Chapman.

Sarah Hart CU Boulder

Sarah Hart

The impetus for the study was in part the severe and extensive native bark beetle outbreaks in response to warming temperatures and drought over the past 15 years that have caused dramatic tree mortality from Alaska to the American Southwest, said Hart. Mountain pine beetles killed more than 24,700 square miles of forest across the Western U.S. in that time period, an area nearly as large as Lake Superior.

“The question was still out there about whether bark beetle outbreaks really have affected subsequent fires,” Hart said. “We wanted to take a broad-scale, top-down approach and look at all of the fires across the Western U.S. and see the emergent effects of bark beetle kill on fires.”

Previous studies examining the effect of bark beetles on wildfire activity have been much smaller in scale, assessing the impact of the insects on one or only a few fires, said Hart. This is the first study to look at trends from multiple years across the entire Western U.S. While several of the small studies indicated bark beetle activity was not a significant factor, some computer modeling studies conclude the opposite.

The CU-Boulder team used ground, airplane and satellite data from the U.S. Forest Service and the U.S. Geological Survey to produce maps of both beetle infestation and the extent of wildfire burns across the West.

The two factors that appear to play the most important roles in larger Western forest fires include climate change — temperatures in the West have risen by about 2 degrees Fahrenheit since 1970 as a result of increasing greenhouse gases — and a prolonged Western drought, which has been ongoing since 2002.

“What we are seeing in this study is that at broad scales, fire does not necessarily follow mountain pine beetles,” said Schoennagel. “It’s well known, however, that fire does follow drought.”

The 2014 Farm Bill allocated $200 million to reduce the risk of insect outbreak, disease and subsequent wildfire across roughly 70,000 square miles of National Forest land in the West, said Hart. “We believe the government needs to be smart about how these funds are spent based on what the science is telling us,” she said. “If the money is spent on increasing the safety of firefighters, for example, or protecting homes at risk of burning from forest fires, we think that makes sense.”

Firefighting in forests that have been killed by mountain pine beetles will continue to be a big challenge, said Schoennagel. But thinning such forests in an attempt to mitigate the chance of burning is probably not an effective strategy.

“I think what is really powerful about our study is its broad scale,” said Hart. “It is pretty conclusive that we are not seeing an increase in areas burned even as we see an increase in the mountain pine beetle outbreaks,” she said.

“These results refute the assumption that increased bark beetle activity has increased area burned,” wrote the researchers in PNAS. “Therefore, policy discussions should focus on societal adaptation to the effect of the underlying drivers: warmer temperatures and increased drought.”

The entire paper can be downloaded (1MB).
Reports about other pine beetle studies, and general articles on the insects, are tagged beetles.

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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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Wednesday morning one-liners

Engine rollover, Warm Springs, Oregon

Engine rollover, Warm Springs, Oregon, July 18, 2014.

*The Wildland Fire Lessons Learned Center has published a report on a BIA engine that rolled over near Warm Springs, Oregon, July 18, 2014. Two people were injured, one seriously. The LLC says more than 50 fire vehicles have rolled over in the last 10 years.

*A Colorado artist has created a work consisting of rectilinear pillars suspended from the ceiling, each measuring nine feet tall, meant to convey the idea of a wildfire.

*A man spotted running from the 50-acre Foothill Fire in Ventura, California was arrested on suspicion of setting the blaze.

*Fire officials in Washington state suspect an arsonist is responsible for igniting 23 fires in less than two weeks. Most of them have been vegetation fires.

*A firefighting vehicle in Australia has been outfitted with drop-down steel wheels so that it can follow a steam-powered train, putting out wildfires started by the steam engine.

*In other news from Australia, a Senator gave a speech, titled, Thank you For Smoking, praising nicotine fiends for their $8 billion a year contribution to the economy. He said he did the math: Last year smokers cost the health care system $320 million and another $150 million in bushfire control.

*Researchers have found that “recent (2001–2010) beetle outbreak severity was unrelated to most field measures of subsequent fire severity, which was instead driven primarily by extreme burning conditions (weather) and topography.” Unfortunately, to read the article, researched and published by government employees, it will cost you $10 for two days of access. If the researchers, Brian J. Harvey, Daniel C. Donato, and Monica G. Turner, are going to hide the results of their taxpayer-funded research behind a pay wall, what’s the point in hiring researchers? Support Open Access.

*Firefighters are on alert in the Philippines for wildfires that may start from an eruption of the Mayon volcano.

*Firefighters are on lessened alert in the Black Hills after the area received two to five inches of rain over the last few days.

*California has burned through its wildfire-fighting budget — $209 million — just as it faces what is historically the worst of the fire season.

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Fighting fire in a beetle-killed forest

Mountain Pine Beetle, matchWhen a forest that has been attacked by pine beetles is on fire, there is a lot that we do not know about the flammability, crown fire potential, and resistance to control of these burning stands of conifers. Testing the torching potential of individual beetle-killed crowns was conducted in the winter over a ground covered with snow using a propane burner as the heat source. Flammability of vegetation has been evaluated in a lab. But it has not been proven that existing fire spread models can accurately predict the rate of spread of a stand of trees that has been attacked by pine beetles. As the authors of the paper below stated:

It is a shocking admission that the only empirical investigation of fire behaviour in live, lodgepole pine stands is limited to a single study, involving surface fires, carried out in British Columbia, Canada, 45 years ago (Lawson, 1972;1973).

In an effort to summarize what we do and do not know, three scientists, Wesley G. Page, Michael J. Jenkins, and Martin E. Alexander, collaborated on a paper titled Crown fire potential in lodgepole pine forests during the red stage of mountain pine beetle attack. The entire paper can be read here — their conclusions are below:

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“Conclusions

True insight into understanding and predicting the possible effects of recent [Mountain Pine Beetle] MPB-caused tree mortality on surface and crown fire potential in lodgepole pine forests has so far proven to be largely an intractable problem. While significant progress has been made in recent years documenting the effects of MPB-related tree mortality on fuel complex structure as well as seasonal and diurnal fuel moistures, trying to accurately assess potential fire behaviour using either operational or physics-based fire behaviour models has proven problematic. Except for the recent development in British Columbia, Canada, with respect to astatisticalmodel(Perrakis et al., 2012), existing models tend to be either inappropriate and/or un-validated for use in MPB-attacked forests. Current operational fire behaviour models used in the US are not capable of addressing the complex spatial arrangements of crown fuels that occur in recently attacked stands. Physics-based models such as WFDS may in time serve to be useful research tools and aid in understanding the dynamic nature of fire behaviour, but until the limitations and sources of error are better understood, interpretations of the resulting simulations must be viewed with scepticism (Alexander and Cruz, 2013a).

Observations from experimental fires and wildfires indicate that a real and considerable increase in crown fire potential exists in recently attacked stands with an increase in rate of spread on the order of 2 –3 times the no-tree mortality predictions. However, the amount of red foliage within the canopy has important implications on the duration of the increased crown fire hazard. Site-specific factors such as the total and yearly amount of tree mortality, the length of the outbreak, and the preexisting stand conditions could all be important factors that could affect the severityand duration of the crown firehazard. Additional factors such as the juxtaposition of red and green crowns and the relative importance of needle drop and subsequent decreases in CBD vs the increased flammability of red foliage may be important to evaluating crown fire hazard but as yet are not fully understood.

Limitations in the ability to accurately assess crown fire potential in MPB-affected stands are likely to persist until accurate wildfire observations and/or experimental fires can be used to either validate current fire behaviour models or derive the needed empirical proportionality constants in VanWagner’s (1977) crownfire initiation and propagation models applicable to MPB-attacked stands. A program of experimental fires (Alexander and Quintilio, 1990; Stocks et al., 2004a) coupled with more systematic monitoring and documentation of wildfires (Alexander and Taylor, 2010) is needed in order to address these current shortcomings and gain insight into the underlying processes controlling fire behaviour in MPB fuel complexes. It is a shocking admission that the only empirical investigation of fire behaviour in live, lodgepole pine stands is limited to a single study, involving surface fires, carried out in British Columbia, Canada, 45 years ago (Lawson, 1972;1973). Additional information on the physical processes of foliage ignition and the relative effect of moisture content under varying heat fluxes will also aid in the development and modification of physics-based models that would greatly enhance our understanding of fire behaviour in these forest ecosystems (Ma¨kela¨ et al., 2000).

As the number and size of MPB outbreaks in western North America declines, opportunities to conduct experimental fires and observe fire behaviour in recently attacked stands will decrease. Simulating MPB-attack, similar to Schroeder and Mooney (2009; 2012), by girdling trees provides a potential way to extend the window of opportunity for experimental fires and to control for confounding factors. Investments in gathering and compiling fire behaviour data by fire management and fire research organizations will help provide a means to objectively assess fire behaviour potential in this unique fuel complex, which will increase the margin of safety for future wildland firefighters and aid in operational planning for fire managers. Meanwhile, wildland firefighters should continue to be vigilant in recently attacked MPB-affected lodgepole pine forests and follow the guidelines outlined in the fire environment factors listed in the ‘Look Up, Down and Around’ table for insect-killed forests found in the Incident Response Pocket Guide (National Wildfire Coordinating Group, 2010).”

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Colorado state senator rants against federal “absentee landowner”

Some people assume the federal government can do nothing right and use that as an excuse to create fear and rationalize their views. Concerning the national parks and national forests in his state that are owned by the citizens of the United States, a state senator in Colorado, Steve King, has said “absentee landowners” are managing the federal lands.

Senator King and others who may know little or nothing about wildland fire behavior see trees affected by insects (see the tag “beetles”) and assume the forest is now subject to unprecedented explosive forest fires. There is not complete agreement on this, but at least two recent studies have concluded that beetle killed trees do not substantially increase the risk of active crown fire, at least in lodgepole pine (Pinus contorta) and spruce (Picea engelmannii)-fir (Abies spp.). We said the same thing as early as three years ago. Our view is that the resistance to control of a forest fire would increase somewhat one to four years after a beetle outbreak, during the red needle stage, and then would decrease since the crown fire potential would dramatically decline.

Senator King’s opinion about absentee landowners is over the top, but he uses that argument to justify his state’s acquisition of an air tanker and helicopter fleet to better attack wildfires in Colorado. While his goal may be laudable, his tactics are not. And keep in mind, aircraft do not put out fires. Under ideal weather, fuel, and topography conditions, they can slow down a fire providing firefighters on the ground an opportunity to suppress it. If those conditions do not exist, such as during strong winds, aircraft are virtually useless as a fire suppression tool.

Below is an excerpt from an article written by the senator, and following that, a portion of a newspaper’s editorial in response.

…Absentee owners are allowing brush and beetle-kill trees to collect to the point of criminal negligence, putting all property owners at risk of being victims of a catastrophic wildfire.

The absentee owner here is the federal government: 36.6 percent of Colorado land is under the control and “ownership” of the federal government. A very high percentage of dead federal beetle-kill trees that have blown down now are surrounding Colorado’s precious life sustaining water sheds.

If any other Colorado land owner allowed their property to de-evolve to the state of federal lands in the WUI and around our water sheds, the state of Colorado would declare the land blighted and exercise eminent domain to take that land under state control. We are in a critical race against time to remediate the land before it is too late for our water, air and land to be saved from the specter of a catastrophic wildfire…

Grand Junction’s Daily Sentinel responded to Senator King’s remarks. Below is an excerpt:

…State Sen. Steve King’s latest offering – “Don’t count on federal landowners to aid in fighting wildfires in Colorado” – epitomizes the incoherence of Republicans’ pandering policy prescriptions.

The federal government manages 23 millions acres of wilderness, National Forest, and BLM lands in Colorado – where fires are often naturally occurring regenerative events.

Coloradans have chosen to build homes adjacent to those lands – ignoring the inherent risks of doing so, which are apparently increasing as a result of global climate change.

King conveniently places the onus of fire suppression responsibility on the public side of the “wildland-urban interface”—rather than on “urbanites”—and falsely insinuates that the federal government is “absent” when wildfires originate on federally-managed lands.

Moreover, King curiously does not advocate a commensurate exercise of “eminent domain” against absentee private landowners who neglect their property, counties that refuse to enact sensible zoning ordinances, and/or individuals who fail to demonstrate “personal responsibility” by acquiring adequate and actuarially-priced fire insurance.

Instead, King calls on Colorado’s “government” to insure those “free riders” by imposing increased tax burdens on more prudent citizens who opt not to assume the risk of closely locating near the viewsheds afforded by Colorado’s scenic landscapes, while begging the question of how many firefighting aircraft are needed and who would pay for them…

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Wildfire briefing, November 7, 2013

USDA awards $10 million grant to explore uses for beetle-killed trees

The U.S. Department of Agriculture has awarded a $10 million grant to a consortium to investigate methods for turning trees killed by beetles into biofuel. Led by Colorado State University, the group includes Cool Planet Energy Systems, Colorado State Forest Service, the U.S. Department of Energy’s National Renewable Energy Laboratory, University of Wyoming, University of Montana, Montana State University, University of Idaho, and the Forest Service’s Rocky Mountain Research Station.

Red Skies of Montana on DVD

If you liked the historic film Watershed Wildfire about the 1955 Refugio Canyon Fire, you would probably enjoy the 1952 classic movie Red Skies of Montana, which was very loosely based on the 1949 Mann Gulch Fire that claimed the lives of 13 firefighters, including 12 smokejumpers. With the cooperation of the U.S. Forest Service, the Technicolor film was shot in and around Missoula, Montana and stars Richard Widmark, Constance Smith, Jeffery Hunter, and Richard Boone. I believe this movie is where the myth of exploding trees was created.

The National Smokejumper Association sells the DVD for $15.

A description of the movie from Wikipedia:

Cliff Mason, a veteran foreman of the Forest Service’s smokejumper unit, is called out with a crew on a fire, despite the fact that they have not rested in three days. Accompanied by R. A. “Pop” Miller and four other men, Cliff leaves the smokejumper base at Missoula, Montana to parachute into a nearly inaccessible area of Bugle Peak. Hours later, at base, superintendent Richard “Dick” Dryer becomes worried because Cliff is not answering radio calls. The next day, after the fire crowns, Dick flies by helicopter into the area and is stunned to find only Cliff, in shock and wandering through the devastated region. Cliff is rushed to the hospital, where he gradually recovers, although he cannot remember how he got separated from his men, or why he was the only one to survive.

Wildfire music

Did you know there is a band named “Forest Fire“?

And in other news about music related to fire, a video is available featuring a song titled “I See Fire” that will be in the upcoming Hobbit sequel The Desolation of Smaug, which will open in theaters December 10. The song was written and performed by Ed Sheeran, who played all of the instruments in the recording except for the cello. Earlier this week he tweeted, “Managed to learn violin for a day”.

Below is a screen shot from the music video, and below that, the video itself.

Ed Sheeran - I See Fire

A link to the video on YouTube.

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