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By: Luke deBarathy Advisor: Dr. Liv Haselbach

ABSTRACT:

The mountain pine beetle (MPB) epidemic is one of the most devastating insect outbreak since the

great locust swarms of the 1870s and is an environmental disaster comparable to the dust bowl of the

1930s. The typical state of many North American pine forests -- mature, homogeneous, even-aged, and

dense -- combine into volatile environmental conditions primed for a MPB population explosion. The

unusually warm and dry climate of the past couple decades has fueled the beetles reproduction. The

resulting outbreaks have engulfed millions of acres of pine forests from southern California to Alaska.

The aftermath has left billions of dead trees. If the trees are not harvested, they will eventually

become a carbon source releasing CO2 back into the air either rapidly through forest fire or slowly through

decay. Canadas Pacific Forestry Center has conducted studies revealing that the magnitude of the beetle

disturbance is great enough to completely reverse the carbon cycle of the forest. Furthermore, a study from

the University of Idaho estimates that infested stands will take a generation to regain their living biomass

and the average stand will take over a century for its carbon flux to become a net sink again. Carbon

emissions from forest fires are also expected to dramatically increase in correlation with the beetle-kill.

Limiting the impact of the MPBs carbon footprint will require proactive forest management that

emphasizes both economic benefit and forest health. Harvesting beetle-kill trees for lumber, pulp, and other

commercial products permanently sequesters the carbon in the wood. Furthermore, bio-mass from beetle-

kill can be utilized for energy production as a substitute for fossil fuels. In a time of high unemployment

and recession, this could be at least a short term boom for many existing and new businesses. Replanting

landscapes that are more biologically diverse will reduce the likelihood of future epidemics and

simultaneously accelerate the forests carbon offset potential.

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INTRODUCTION: QUANTIFYING THE NATURAL DISASTER

Butte Montana was once known as the Richest Hill on Earth boasting the largest open pit copper

mine in North America. In 1983 the Berkeley Pit, which can be seen in Figure 1, closed and shortly

thereafter Butte received a more infamous moniker: the largest Superfund site in the country (Everett,

n.d.). Surprisingly, cleaning up the contamination and pollution from past copper mining and smelting

activities is not the greatest environmental crisis that concerns the "Mining City."

Figure 1: Butte Montana. The Berkeley Pit shadowed by the East Ridge's pine forests

Over the past 15 years, the residents of Butte have watched the slow motion death of most of the

scenic pine forests that surround the city. For hundreds of miles in every direction trees have been turning

from a lush green to an ominous red and then to a haunting gray. The stages of attack are exemplified in

Figure 4. A good comparison of the forests surrounding Butte's Lady of the Rockies monument between

1991 and 2011 is shown in Figure 2. Butte is at the epicenter of a natural disaster so vast that it threatens

ecological, social, and economic upheaval for both the United States and Canada. The culprit for the

unprecedented forest die-off is an insect no larger than a grain of rice, the mountain pine beetle (MPB)

(Leatherman, Aguayo, & Mehall, 2007).

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Figure 2: The Lady of the Rockies. Left 1992, Right 2011.

Between 1996 and 2011, MPB outbreaks have spread from southern California to Alaska infecting

millions of acres of forest in the western United States and Canada (Malhi, 2002). Most pines found in

North America are suitable hosts for the mountain pine beetle (Logan, 2001), and the mortality rates for

mature pine trees within an infested area often exceed 80% (Kurz, 2008). The epidemic continues to

proliferate at an alarming rate. It has reached central Alberta where the lodgepole pine forests of the west

converge with jack pine forests that stretch east all the way to the Atlantic Ocean. As soon as the mountain

pine beetle infests the jack pine forests, the devastation is expected to spread rapidly across Canada and

southward through the United States (Gorte, 2009). The jack pine is more susceptible to infestation because

it has not evolved the defenses to resist and survive beetle attacks that the lodgepole pine has developed

(Gorte, 2009). The likely consequence of this scenario is a mass die-off of continental scale. Note from

Figure 3 that once the beetles reach the Great Lakes, they can infest the white pine forests on the East Coast

and spread through the yellow pine forests that cover the southern states (Gorte, 2009).

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Figure 3: Mountain Pine Beetle Distribution Map.

CULTIVATING THE CRISES

Although bark beetle infestations are a regular force of natural change in forested ecosystems, the

current outbreak has burgeoned into the largest and most severe in recorded history (U.S. Forest Service,

2011). Several conditions have contributed to the extreme scale of the current epidemic. Foremost, the

current generation of forests that characterizes the western United States and Canada are ideal hosts for the

beetle because they are mature, homogeneous, and even-aged largely due to a combination of widespread

severe wildfires (Logan, 2001) and large scale, intense logging that occurred at the turn of the 19th century

(U.S. Forest Service, 2011).

In the 20th century, the Forest Service focused on suppressing wildfire leading to unnaturally dense

forest conditions. Moreover, compliance with an ever expanding bureaucracy and onerous environmental

regulations has made logging and thinning evermore protracted and cost prohibitive (Willms, 2010). Trees

growing in an overcrowded environment must compete for resources causing the trees to become stressed

and more vulnerable to infestation (U.S. Forest Service, 2011). Likewise, drought weakens the ability of

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trees to resist and survive an infestation. Many of the regions hardest hit by the bark beetle conquest have

correspondingly experienced drought conditions (U.S. Forest Service, 2011).

Figure 4: Stages of Attack.

THE CLIMATE FOR THE BEETLES PERFECT STORM

In addition to shifts in precipitation patterns and associated drought, climate conditions over the

past 20 years have been ideal for the beetles reproduction. The mountain pine beetle is a seasonally adapted

univoltine (has a one year life cycle), and its reproductive success is very sensitive to temperature (Bentz,

2010). The complete lifecycle of the mountain pine beetle is illustrated in Figure 6. The life cycle of the

beetle begins in the late summer when their eggs hatch about two weeks after being laid (called oviposition)

(Logan, 2001). The larvae begin feeding on the innermost bark layer, called the phloem, of the pine tree

and begin producing glycerol, a natural antifreeze that allows the larvae to survive extreme winter

temperatures (Leatherman, Aguayo, & Mehall, 2007). The beetle larvae are particularly vulnerable to late

summer frosts prior to producing ample glycerol. However, once the larvae are established for winter,

temperatures must drop to -30F for five consecutive days to significantly reduce the beetles population

(Logan, 2001).

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The larvae continue feeding throughout winter creating tunnels through the trees phloem.

Eventually these tunnels, shown in Figure 5, cut off the exchange of nutrients between the trees roots and

its crown killing the tree (Logan, 2001).

Figure 5: Mountain Pine Beetle Galleries.

The larvae pupate in the early summer and the emergence of adult beetles begins in June and

continues through September with the majority of beetles exiting their host trees in late July (lodgepole

pine) and mid-August (ponderosa pine) (Leatherman, Aguayo, & Mehall, 2007). Cold and wet weather

jeopardizes beetles that emerge too early. The female beetles take flight and typically seek trees with trunk

diameters larger than 4 inches (U.S. Forest Service, 2011) because mature trees have a thicker phloem that

is better able to provide the larvae with ample sustenance (Leatherman, Aguayo, & Mehall, 2007).

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Figure 6: The Mountain Pine Beetle Lifecycle (Wyoming Forestry Division ).

A noteworthy aspect of this cycle is the transmission of blue-stain fungi between host trees. Spores

affix to the bodies of the adult beetles as they emerge from their domicile and are introduced to the new

host tree upon attack. The fungus stains the sapwood a distinct blue-gray color, and clogs the water

transport systems of the tree which weakens the tree and ultimately assists the beetle in symbiotically killing

the tree (Leatherman, Aguayo, & Mehall, 2007). Once a tree is infested, there is nothing economically

viable that can be done to save that tree (Gorte, 2009). As shown in Figure 7, the blue-stain fungus alters

the appearance of the wood, but it does not affect the structural properties of the wood (Gorte, 2009).

Because the fungus absorbs and traps moisture, it does accelerate decomposition of the wood. Beetle-killed

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trees can be harvested for lumber for at least 5 years after mortality and up to 18 years depending on the

circumstances (Gorte, 2009).

Figure 7: Blue Wood.

The dispersion range of the mountain pine beetle is typically less than a mile before the female

beetles find a suitable host tree. Although the beetle is a weak flyer, experiments performed by John

Byers, a professor at the Swedish University of Agricultural Sciences, estimates that the beetle is capable

of taking advantage of wind currents to travel distances up to 28 miles (Byers, 2000). When the female

finds a suitable tree, she bores through its bark creating an egg gallery and releases aggregating

pheromones which attract males for mating as well as other females who attack the area in mass (Logan,

2001). This is the primary reason homogeneous even-aged stands are particularly vulnerable to bark beetle

outbreaks. After mating, the female typically lays about 75 eggs (Leatherman, Aguayo, & Mehall, 2007).

If the offspring are not exposed to lethally cold weather conditions, enough beetles can emerge from an

infested tree to kill multiple trees the following year (Logan, 2001).

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SINKING FORESTS AND CHANGING THE CARBON CYCLE

Global warming alarmists regard the mountain pine beetle outbreak as a direct consequence of

anthropogenic induced climate change and a harbinger of impending global ecological disaster correlated

with emissions from the combustion of fossil fuels. Arguments linking the beetle outbreak and global

warming are routinely made by advocacy groups lobbying for policies aimed at reducing greenhouse gas

emissions. Perhaps, the most influential of which is the Alliance for Climate Protection (ACP). ACP was

founded by former Vice President Al Gore in 2006 and boasts over 5 million members and has hundreds

of millions of dollars at its disposal (Climate Reality Project, 2012). In 2008, ACP launched the 34 million

dollar RePower America Campaign with the objective of gaining support for climate change legislation

(Repower America, 2012).

At an event held at Mount Rushmore, Repower America spokesman, Matt McGovern, opened his

oration with the following statement, The effects of global warming can be seen in the growing splotches

of brown trees scattered throughout the otherwise green sheen of the Black Hills National Forest.

Shadowed by the monuments bust of Teddy Roosevelt, forefather of American wildlife conservation, Mr.

McGovern announced, The plague of mountain pine beetle infestations in forests across the American

West is happening on a scale that is symptomatic of a world-wide climate-change problem. The beetles

thrive in a warmer climate, which doesnt provide the degree of temperature lows needed to kill the bugs.

An overwhelming majority of scientists agree that those environmental conditions are tied to warming in

the earths atmosphere caused by increased CO2 emissions from a variety of man-made sources, including

coal-fired electrical plants. He then went on to rally for support for the reform package backed by

President Obama and congressional Democratic leaders that would tax emissions from carbon producers

such as coal plants and promote alternative energy production such as wind and solar (Woster, 2009).

Dave Thom, a natural resources specialist with the Black Hills National Forest, was asked to react

to McGoverns speech for a Rapid City Journal news article covering the event. Mr. Thom emphasized the

dense and mature biogeographics of the forest as the primary causation fueling the beetle conflagration and

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downplayed linking the outbreak with manmade global warming saying, [bark beetle outbreaks] can

happen regardless of a few degrees of change in temperature measured on a global scale. He then

explained the necessity for the U.S. Forest Service to continue thinning the forests because, The

management work we do year to year has a greater effect reducing infestation than climate changes that

occur over decades (Woster, 2009). A comprehensive scientific explanation that answers how a 0.59 C

increase in average global temperatures between 1900 and 2011 (National Aeronautics and Space

Administration Goddard Institute for Space Studies, 2012) is the critical catalyst responsible for the

outbreaks unprecedented size and scale could not be found for this literature review. While the beetle

epidemic is the largest in recorded history, the fact remains that the regular low temperatures needed to

suppress the beetles conquest also have not occurred in recorded history with the exception of perhaps the

northern most reaches of the outbreak.

The degree to which global warming has influenced the current beetle epidemic is controversial

and uncertain; however, the outbreak certainly reduces the effectiveness of the infected forest to act as a

carbon sink because the billions of trees killed by beetles cease consuming CO2 from the atmosphere.

Moreover, these trees eventually become a carbon source releasing carbon back into the air either rapidly

through forest fire or slowly through decay (Ryan, 2008).

W.A. Kurz, a senior research scientist with Canadas Pacific Forestry Center as well as Coordinator

of the Carbon Task Force of the International Union of Forest Research Organizations, is the formost expert

on insect disturbances in forest ecosystems and on the effects such disturbances have on the carbon cycle.

W.A. Kurz published a startling study in Nature modeling the carbon cycle of a sample area located in the

south-central region of British Columbia that has been overwhelmed by the beetle outbreak. A map and

photo of the sample area is shown in Figure 8. The model accounts for annual tree growth, litter-fall,

turnover and decay, and explicitly simulates beetle caused mortality over the sample area. The studys data

reveals the outbreak turned the forestland from a net carbon sink to a large carbon source both during and

immediately after the outbreak. The net carbon dioxide equivalent sink loss caused by the beetle epidemic

over 21 years is estimated at 990 Mt CO2e (Kurz W. A., 2008). For comparison, the anthropogenic

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emissions of greenhouse gases from all of Canadian sources in 2005 was about 747 Mt CO2e (Government

of Canada, 2007), and average emissions from forest fires in all of Canada are approximately 162 Mt CO2e

per year (Amiro, 2001).

Figure 8: Sample Area of Kurz's Research [8].

E.M. Pfeifer and Jeffrey Hicke, forestry professors at the University of Idaho, headed a study

measuring aboveground tree stocks and modeling carbon fluxes following a bark beetle outbreak. Their

findings corroborate and augment the conclusions from the Nature article. The study estimates that stands

attacked by beetles take 7 to 25 years to regain their original living biomass. As expected, stands with the

highest mortality rates take the longest to regenerate. However, even after the stand has ostensibly

recovered from the infestation, it continues to suffer a long term drop in the rate that it metabolizes and

sequesters carbon dioxide. Affected stands on average would take over a century for their carbon flux to

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become a net sink again (Byers, 2000). If left to natural cycles, the millions of acres of forestland affected

by the beetle will remain carbon sources until the 22nd century.

FIRE IMPACTS

Forest fires conflate and compound the carbon footprint of the bark beetle. Net carbon emissions

from forest fires are expected to escalate dramatically over the next several years due to additional fire

hazard correlated with the 30 billion dead and dying trees that have been girdled and killed by the mountain

pine beetle. The basic ecologic cycle of the lodgepole pine forest is dependent on the inter-relationship

between beetle-caused mortality and subsequent fire (Logan, 2001). The mountain pine beetle acts as

natures forest manager by attacking stands of mature pines and leaving stands of saplings. A fire replacing

stand usually occurs within 15 years following an outbreak (Gorte, 2009). If forest fires do not occur, more

shade tolerant species such as spruce and fir eventually replace the pine stand because the serotinous cones

of the pine require heat from a fire to release its seeds (Gorte, 2009).

Dead needles provide a highly combustible source of fine fuels and the dry and decaying trees

provide a source of ignition maintenance for lightning strikes. Once ignited, decaying logs are capable of

smoldering for weeks until hot, windy, and dry weather conditions incite a firestorm (Logan, 2001). Years

of strategic fire suppression has exacerbated the volatile situation on the ground. The forest floor contains

nearly double the biomass compared to the natural conditions prior to European settlement (USDA Forest

Service, 2011). This increases the risk of a large-scale fire that could sterilize the soil and delay the

regeneration of the forest for decades. This in turn increases erosion and pollution of our water sources

(Logan, 2001). Figure 9 is a photo of a forest where the soil has been sterilized by a recent wildfire.

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Figure 9: Sterilized Soil by Wildfire.

A study on fire behavior in beetle-killed lodgepole pine forests found that both the fireline intensity

and the rate of fire spread are higher in beetle-killed stands in comparison to endemic stands (Page &

Jenkins, 2007). Dr. Brian Amiro, professor at the University of Manitoba and Research Scientist with the

Canadian Forest Service, led an investigation on Canadas ever-growing forest fire hazard. The studys

report forecasts that emissions due to forest fire will likely double from the current levels to 313 Mt CO2e

per year as result of disturbances from insects, exceedingly dense forest conditions, and drought related to

climate change (Amiro, Cantin, Flannigan, & Groot, 2009). If this prediction is accurate, annual carbon

dioxide equivalent emissions from forest fires will be grow to about 1.5 times that produced by the entire

Canadian transportation sector in 2005 (200 Mt CO2e) (Government of Canada, 2007).

Those who have lived in areas prone to forest fires are not surprised by this statistic. The worst

Los Angeles smog is marginal in comparison to the air pollution during fire season in Butte Montana, where

smoke and particulate matter is often so thick ones vision is limited to less than a mile and average people

are advised to where protective masks and respirators while outdoors (Duganz, 2006). Those with asthma,

emphysema, and heart conditions experience aggravated symptoms and are at advanced risk for

complications and often spend the late summer months in agony (Fowler, 2003). People, usually the elderly,

with severe respiratory or pulmonary conditions must be quarantined into hospice facilities with particle

filtration systems (Missoula City-County Health Department, 2010).

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CONCLUSION

The mountain pine beetle has caused dramatic changes to the ecosystem. From the looks of the

Forest Services internal review regarding its response to the outbreak, it appears the beetle is also

responsible for dramatic changes in the Forest Services allocation of resources, evaluation of priorities,

and management philosophy (USDA Forest Service, 2011). In the past, the majority of the Forest Services

resources were dedicated to aggressively fighting forest fires to protect living forests. Now, the Forest

Services top priority is focusing on reestablishment of the millions of acres of dead forests (USDA Forest

Service, 2011). Forest managers are determined to learn from past mistakes by employing forestry practices

to create more biologically diverse forest landscapes that will reduce the likelihood of future epidemics and

the severity of the consequences when epidemics occur (U.S. Forest Service, 2011). This was not merely

a mountain pine beetle epidemic, but also an epidemic of pine.

The studies conducted by Dr. Kurz, Dr. Pfeifer, Dr. Hicke, and others on the mountain pine beetle

epidemic confirm that disturbances are principle drivers of the forest carbon budget. Their work also serves

as a microcosm highlighting the vital role forests play in the global carbon cycle, and the potential benefits

that good forest management practices can have in offsetting emissions from anthropogenic fossil fuel

combustion. Harvesting beetle-kill trees for lumber, pulp, and other commercial products permanently

sequesters the carbon in the wood. In addition, material substitutes to wood such as steel, plastic, and

concrete require more energy to produce because they are the products of mining, possessing, and

manufacturing (Ryan, 2008). This translates to more energy being used and greenhouse gases being

emitted. Furthermore, bio-mass from beetle-kill can be utilized for energy production as a substitute for

fossil fuels. Burning biomass, a renewable resource, generally means that fossil fuel will not be burned

(Ryan, 2008).

Given the vast amount of carbon sequestered within the beetle-kill trees, one would expect that

environmental and political organizations concerned about global warming, such as the aforementioned

Alliance for Climate Protection, are boisterously advocating for harvesting and utilizing these trees. While

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the ACP found it useful to point out the beetle-kill trees in order to advance its carbon tax agenda, it is silent

on using the beetle-kill to prevent the advance of the carbon positive feedback loop created if the trees are

left to rot or burn (Climate Reality Project, 2012). Seems when the carbon problem is disassociated from

a tax solution, the carbon loses its value and is no longer a worthwhile issue for most environmentalists

concerned about global warming. One is probably wasting his carbon-laden breath trying to convince self-

described tree huggers to embrace logging in any capacity.

Perhaps the best way to increase demand of beetle-kill products is to encourage wood certification

organizations to give preferential treatment to forest lands that have suffered catastrophic forest loss due to

extraordinary disturbances from not just insects but also fire and disease. After all, prioritizing dead and

diseased trees not only decreases demand for healthy trees on virgin lands, but also encourages active forest

stewardship in areas that need it most. The Forest Stewardship Council (FSC), the Sustainable Forest

Initiative (SFI), and the Program for the Endorsement of Forest Certification (PEFC) all aim to ensure

forests are managed in a sustainable and ecologically sound manner and thus limit the quantity of wood

that can be harvested for a given area. Dead trees in areas impacted by large disturbances simply should

not be counted in the same manner as healthy trees with respect to harvesting restrictions. If beetle-kill

could receive an addendum for certification, blue wood would in turn be considered a preferable material

in the U.S. Green Building Council's green rating system, LEED, as well as in the International Code

Council's 2012 Green Construction Code thereby gaining market share as a material among green conscious

consumers and builders.

While the beetle tsunami has been devastating, the tragedy will be compounded if the wood of the

dead trees left in its wake are wasted. The commercial lifespan of beetle-kill pine trees is finite and the

wood begins losing its marketability after 5 years (Gorte, 2009). This gives only a small window of time

through which salvaging the near endless supply of beetle-kill trees remains feasible. In a time of high

unemployment and recession, this could be at least a short term boom for many existing and new businesses.

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REFERENCES

1. Bentz, Barbara. 2008. Western U.S. Bark Beetles and Climate Change. (May 20, 2008). U.S.

Department of Agriculture, Forest Service, Climate Change Resource

Center. http://www.fs.fed.us/ccrc/topics/bark-beetles.shtml

2. Ryan, Michael G. 2008. Forests and Carbon Storage. (June 04, 2008). U.S. Department of

Agriculture, Forest Service, Climate Change Resource

Center. http://www.fs.fed.us/ccrc/topics/carbon.shtml

3. GISS Surface Temperature Analysis (GISTEMP) National Aeronautics and Space Administration

Goddard Institute for Space Studies. 2/14/2012, http://data.giss.nasa.gov/gistemp/

4. U.S. Forest Service. Western Bark Beetle Strategy. (July 11, 2011).

http://www.fs.usda.gov/main/barkbeetle/home

5. Ross W. Gorte, Cong. Research Serv., R40203, Mountain Pine Beetles and Forest Destruction:

Effects, Responses, and Relationship to Climate Change 1 (2009).

6. Willms, J. David; The Mountain Pine Beetle: How Forest Mismanagement And A Flawed Regulatory

Structure Contributed To An Uncontrollable Epidemic

7. Wesley Page & Michael J. Jenkins, Predicted Fire behavior in Selected Mountain Pine beetle-Infested

lodgepole Pine, 53 foreSt ScI. 662, 673 (2007), available at http://www.wy.blm.gov/

fireuse/pubs/FireBehavior-PineBeetle.pdf.

8. Kurz, W. A., Dymond, C. C., Stinson, G., Rampley, G. J., Neilson, E. T., Carroll, A. L., Safranyik,

L., ... Ebata, T. (April 24, 2008). Mountain pine beetle and forest carbon feedback to climate

change. Nature, 452, 7190, 987-990

9. Jesse A. Logan and James A. Powell, Ecological Consequences of Climate Change Altered Forest

Insect Disturbance Regimes, Climate Change in Western North America: Evidence and

Environmental Effects , Univ. of Utah Press, Salt Lake City, UT, in press.Bottom of Form

10. Everett, George. Only In Butte. 2003. 1/16/2012 http://www.butteamerica.com/oib.htm

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11. Pfeifer, E. M., Hicke, J. A., & Meddens, A. J. H. (January 01, 2011). Observations and modeling of

aboveground tree carbon stocks and fluxes following a bark beetle outbreak in the western United

States.Global Change Biology, 17, 1, 339-350.

12. D.A. Leatherman, I. Aguayo & T.M. Mehall, Mountain Pine Beetle, Trees & Shrubs no.5.528 (Colo.

State Univ. Extension, Fort Collins, Colo.), Apr. 2007, available at

http://www.ext.colostate.edu/pubs/insect/05528.pdf.

13. Byers, J. A. (January 01, 2000). Wind-aided dispersal of simulated bark beetles flying through

forests. Ecological Modelling, 125, 2, 231 Byers, John A, 1999, Swedish University of Agricultural

Sciences, Plant Protection, S-230 53, accepted 9 August 1999, Wind-aided dispersal of simulated

bark beetles flying through forests

14. Logan, J. A., & Powell, J. A. (January 01, 2001). Articles - Features - Ghost Forest, Global Warming,

and the Mountain Pine Beetle (Coleoptera: Scolytidae) - Outbreaks of the mountain pine beetle are an

important part of ecological cycles in western pine forests and have provided researchers with

insights into both the beetle's and the forest's evolutionary adaptability. American Entomologist, 47, 3,

160.

15. Kurz, W. A., Stinson, G., & Rampley, G. (January 01, 2008). Could increased boreal forest

ecosystem productivity offset carbon losses from increased disturbances?. Philosophical Transactions

of the Royal Society of London. Series B, Biological Sciences, 363, 1501, 2261.

16. Review of the Forest Service response--the bark beetle outbreak in northern Colorado and southern

Wyoming. (2011). S.l.: USDA Forest Service, Rocky Mountain Region and Rocky Mountain

Research Station

17. Amiro, B.D., A. Cantin, M.D. Flannigan, and W.J. de Groot, NRC Research Press, Future emissions

from Canadian boreal forest fires

18. Amiro, B. D., Todd, J. B., Wotton, B. M., Logan, K. A., Flannigan, M. D., Stocks, B. J., Mason, J. A.,

... Hirsch, K. G. (January 01, 2001). Direct carbon emissions from Canadian forest fires, 1959-

1999. Canadian Journal of Forest Research. Journal Canadien De La Recherche Forestiere, 31, 3,

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19. Environment Canada. 2007. Canadas 2005 greenhouse gas inventory: a summary of trends.

Available from http://www.ec.gc.ca/pdb/ghg/inventory_report/2005/2005summary_e.cfm.

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20. Podur, J., Martell, D.L., and Knight, K. 2002. Statistical quality control analysis of forest fire activity

in Canada. Can. J. For. Res. 32: 195205. doi:10.1139/x01-183.

21. Stocks, B.J., Mason, J.A., Todd, J.B., Bosch, E.M., Wotton, B.M., Amiro, B.D., Flannigan, M.D.,

Hirsch, K.G., Logan, K.A., Martell, D.L., and Skinner, W.R. 2002. Large forest fires in

Canada,19591997. J. Geophys. Res. 108. doi:10.1029/2001JD000484.

22. U.S. Environmental Protection Agency. 2007. Inventory of U.S. Greenhouse Gas Emissions and

Sinks: 19902005. Washington, DC: U.S. Environmental Protection Agency.

23. Woster, Kevin, Rapid City Journal, Pine beetle, global warming connection debated 9/19/2009

24. Climate Reality Project, 1/24/2012, http://climaterealityproject.org/

25. Repower America, 1/24/2012, http://www.repoweramerica.org/

26. Malhi, Y., Meir, P., & Brown, S. (August 15, 2002). Forests, carbon and global

climate. Philosophical Transactions: Mathematical, Physical & Engineering Sciences, 360, 1797,

1567-1591

27. Duganz, Pat, The Montana Standard, Smoke Can Be Harmful, 8/16/2006

http://mtstandard.com/news/local/smoke-can-be-harmful/article_d8fefd04-361c-58ed-8a48-

b298793a9d65.html

28. Fowler, Cynthia T. , Journal of Ecological Anthropology Volume 7 2003, p39 to p. 63, Human

Health Impacts of Forest Fires in the Southern United States: A Literature Review

29. Wildfire smoke: A guide for public health officials. Missoula: Missoula City-County Health

Department. 2001

30. Illustration taken from Wyoming Forestry Division Website: http://slf-

web.state.wy.us/oldsite/forestry/healthassist2.aspx