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.


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.


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:



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).”


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…


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.


More evidence about the effects of beetles on wildfires

Millions of dollars are being sought or spent on mitigating the effects of bark beetle mortality in the name of preventing disastrous wildfires. Sometimes these efforts are a smoke screen by private companies, or those influenced by their lobbyists, who want to reduce regulations and environmental restrictions on cutting timber on federal lands. At other times the public or even firefighters see dead trees and assume that beetle-killed forests will lead to catastrophic fire behavior. While there is not complete agreement, most of the available science and the preponderance of evidence contradict that assumption.

Beetles are a natural part of the environment and have been around as long as forests. The recent surge in their numbers is due to two factors: warmer weather that kills off fewer of them during the winter, and drought in some areas that reduces the vigor of the trees, decreasing their ability to fend off the attacks.

Dr. Dominik Kulakowski conducted research on insect outbreaks and fires in Rocky Mountain forests for fifteen years. During that time he worked as a research scientist at the University of Colorado and now is a professor at Clark University where he continues to pursue this research.

Below is an excerpt from Dr. Kulakowski’s testimony on April 11, 2013 before the Subcommittee on Public Lands and Environmental Regulation of the Committee on Natural Resources of the United States House of Representatives. He was providing information for the committee members to consider when they vote on H.R. 1442, a proposed bill with a strange name, the “Depleting Risk from Insect Infestation, Soil Erosion, and Catastrophic Fire Act of 2013″.


“…Another example is that of a major outbreak of spruce beetle in spruce and fir forests in Colorado in the 1940s, following which there was substantial concern about the increased risk of fire. But although over 300 fires occurred in that region in the decades that followed, our research found that the forests affected by beetles were no more likely to have burned than other forests. Furthermore, no major fires occurred in those beetle-affected forests in the years and decades that followed the outbreak despite the abundance of dead trees. The most likely explanation for this lack of large severe fires is that climatic conditions in these forests are a more important factor in determining fire risk than is the presence of dead trees. In fact, it was not until a severe drought in 2002 that a large fire affected these forests. During that year there were many wildfires in Colorado, the majority of which burned forests with no recent history of outbreaks.

During the drought of 2002, wildfires also burned some forests in northern Colorado that were attacked by beetles just prior to 2002. The potential increase of fire risk immediately following bark beetle outbreaks is the subject of active research. During this so-called “red phase” dry red needles persist on recently killed trees. It has been hypothesized that the risk of fire may therefore increase during and immediately after outbreaks of bark beetles. Relatively little research has examined fires during the red phase of outbreaks and more research is necessary. However, our examination of the 2002 fires found that outbreaks that immediately preceded those fires affected neither the extent nor severity of fires, most likely because changes in fuels brought about by outbreaks were overridden by weather conditions and other variables.

To understand these scientific findings, which may seem counter-intuitive, we need to consider that (1) bark beetles affect fuels in several ways and (2) several factors are necessary for the occurrence of wildfires. Recent research indicates that reductions in canopy density following outbreaks are actually more important to fire risk than are increases in dead fuel. In other words, beetle-killed trees rapidly lose their needles and this reduces the amount of potentially flammable material in the forest canopy. In contrast, live trees have dense canopies which are critical to the spread of wildfire. Furthermore, and most importantly, in forests dominated by lodgepole pine and spruce there is generally no shortage of flammable material, even in the absence of beetle outbreaks. These forests are characteristically dense and during droughts the risk of severe wildfire is likely to be high, regardless of outbreaks. In sum, catastrophic fire is not an inevitable outcome of bark beetle outbreaks. Instead climate is so important to fire risk in these forests that the effects of outbreaks appear to have comparatively little or no influence.”


Dr. Kulakowski’s complete testimony before the committee.
More information on Wildfire Today about beetles.