Bark Beetles

Firescience.gov newsletter on beetle and fire science..

I’ve always loved Jonathon Winters but, who knew he was so savvy about trees and forests? Here is a classic old Public Service Announcement, for your amusement and enlightenment.

Thanks to Terry Seyden for this link. Note: any photos of pine beetle stands and fire would be appreciated.

Report defies conventional wisdom on pine beetles and wildfire

By ROB CHANEY of the Missoulian

http://missoulian.com/news/local/report-defies-conventional-wisdom-on-pine-beetles-and-wildfire/article_9c505c58-70b5-11e1-b9ab-0019bb2963f4.html

Steve Gage used to worry about his firefighters getting burned. Now the Type I incident commander wonders if they’ll be clubbed to death before they ever reach a forest fire.
The threat comes from the tiny mountain pine beetle, only not in the way most people think. Beetle-killed trees have undermined decades of fire behavior research – because before they burn, dead trees may silently topple. And an unburned falling tree will kill you just as surely as a burning one.
“Now my big concern is how do we approach the thing,” Gage said. “How do we get people into a fire that’s in the middle of beetle-kill safely? Hike them in? Fly them, or put heavy equipment in front of them? And if we can’t get people in safely, how do we engage when the fire comes out?”
Gage has spent 42 years fighting fire. In the last two or three years, he’s seen things that drain away the confidence he’s placed in his tactical handbooks. The reports from 2011’s Saddle and Salt fires in the southern Bitterroot Mountains told of beetle-killed stands on flat ground burning as if they were on steep hillsides or high winds. Colorado forests have seen more than 60 trees a minute blow down in winds of less than 15 mph.
“We’re always thinking about what-if?” Gage said. “If we’ve got an 80 percent chance of success, what does 20 percent failure look like?”
*****
The impact of mountain pine beetles looks very different for environmentalists like Matthew Koehler of the Wild West Institute. Koehler recently circulated a February 2012 Fire Science Digest report on bark beetles, highlighting the following summary:
“Are the beetles setting the stage for larger, more severe wildfires? And are fires bringing on beetle epidemics? Contrary to popular opinion, the answer to both questions seems to be ‘no.’ ”
“We feel as if a lot of the conventional wisdom about bark beetles and wildfire is incorrect,” Koehler said. “The latest science and research coming out seems to support the notion wildfire and beetles are critically important to forest health. We would encourage forest managers and politicians to embrace these natural processes, instead of fear-based rhetoric that leads to justification for more logging or road-building or resource development.”
One of the biggest recent timber sales on the Helena National Forest involves creating a 300-foot safety zone along most secondary roads through Forest Service lands. That sale was predicated on the risk of beetle-killed trees burning or falling on the roads more than on its potential timber value.
Koehler said he understood the reasoning behind clearing trees that threaten campgrounds at Georgetown Lake. But he worried the same reasoning might be used for backcountry logging where the beetle-kill might provide improved wildlife habitat.
Whether the question is tactical – how best to deploy a Hot Shot crew on a fire front? – or managerial (how to justify a timber sale), the mountain pine beetle has chewed its way through mounds of what we used to call normal.
“When people look across a landscape like Lookout Pass and see a lot of red needles, they think they’re looking at a tinderbox,” said fire ecologist Robert Keane at the Missoula Fire Science Laboratory.
*****
The factors he sees defy such simple assumptions.
Current research on beetle-killed trees depends a lot on time and space. Time-wise, it appears a lodgepole pine burns easier within three years of death by pine beetles – when its needles are still green or have turned red – than a live lodgepole. But it’s very hard to tell a dead-but-green “fader” tree from a live one, until it burns.
And Keane said dead trees with needles, regardless of color, appear to burst into dangerous crown fires much easier than live stands. And while firefighters used to simply measure the moisture content of dry wood to determine how fast it could catch fire, it turns out chemical factors like sugars are even more important.
Once the needles fall, after four or five years, the crown-fire hazard falls too. Except that around eight years after death, those “gray ghosts” start toppling. That’s the new problem incident commanders like Gage worry about. And it’s not just trees falling on firefighter’s heads. It’s the difference between having one ton of dry needles per acre on the ground or 100 tons of dry firewood.
“The issue is resistance to control.” Gage said. “When you have a lot of fuel on the ground, it’s like having many logs in your fireplace instead of one. It puts out more heat on the ground. It exponentially adds to the number of people you need. It takes more water. You need more saws to clear paths. It changes where you can put your safety zones.”
Space-wise, the question is where? Keane said a lot of research in fire behavior in Yellowstone National Park doesn’t apply elsewhere, because almost no other place has Yellowstone’s combination of high altitude and volcanic soils.
And those toppling trees? Keane said in parts of British Columbia, foresters have found whole stands of beetle-kill that collapsed into pick-up sticks just three years after infestation. You can’t cut and paste a study in one part of the Rocky Mountains to another and expect identical results.
Once the needles have fallen, sunlight and rain can foster low-growing shrubs. In some places, that provides new ladder fuels which can ignite the dead trees. In others, the moist shrubs lower the chance of a fire getting going.
Fire Sciences Laboratory program manager Colin Hardy said pine beetles have upended whole shelves of assumptions his researchers have depended on for decades.
“The models everybody uses on an operational basis were developed in 1972,” Hardy said. “They were designed for firefighter safety and fire suppression of surface fires.”
Those models don’t account for crown fires, climate change, population changes, backcountry subdivisions – let alone mountain pine beetle infestations.
Current studies of beetle effects have been running for 15 years, and they may need 15 more to reveal conclusive answers. It’s like being asked how many ears of corn will come from the kernel you planted yesterday.
And that’s just the beetle questions involving lodgepole pine. Conditions are different for ponderosa pine, or for stands of spruce and Douglas fir infested with spruce budworm. Then there are the new developments in physics that may explain why fires react to different wind conditions or terrain features.
In the corner of Hardy’s conference room stands a refrigerator-sized box with a label that reads “Unisys ES-7000.” It’s a mainframe computer with a once-whopping 32 gigabytes of memory. When it was installed, it chewed through fire behavior models that used to take 38 days of computing in just 17 hours.
“Now our new Cray supercomputer is two orders of magnitude faster,” Hardy said. “It can run that model in about an hour. It’s still not enough.”

Note: you may agree or disagree with the caption to this photo; I just copied it from a USGS science site (Central Mineral and Environmental Resources Science Center) here.

My fire colleagues alerted me that posting of the our previous post here, with simply the introductory paragraph, could have led to the wrong impression of the current scientific thinking.

I think fire managers would like to know better how bark beetle killed or otherwise dead and dry
trees affect fire behavior. But I don;t think that historic vegetation ecology is going to tell folks that. It seems as if some people think that “science” can prove that fires are no different with dead trees, then we wouldn’t have to do fuel treatments. But that doesn’t make sense, since we still do fuel treatments with live trees. Is it about investing more in live tree fuels treatments?

Here is how I frame the question:

Should we, in the interior west, manage tree vegetation outside the WUI (assuming we have agreement in the WUI, some days I am not so sure) to provide possible fire lines, help in some way with suppression of large fires, or to protect other resources?

Framed that way, many more disciplines that fire behavior modeling or historic vegetation ecology might have something to say. Plus of course “should” is a normative (value), and not a science (empirical) question.

And let’s involve a couple of other disciplines right now: hydrologists and fish people don’t seem to be as sanguine about the effects of fire as some vegetation ecologists are; for example, this quote in the JFSP article (pg. 13).

Schnackenberg would like to see much more
operational burning on the Medicine Bow-Routt. “My
opinion as a hydrologist is, I would rather see all that
dead stuff burn right now. It’s standing, and if we wait
for it to fall there may be places where it will burn a
little hot, and you’ll get hydrophobic soils and erosion.
And if you have heavy fuel loads on the ground in 15
years and a fire comes, what happens to the hydrology
then?”

I do agree with the statement at the end of the JFSP piece:

That is a big “how.” And, as with most knotty
management problems, the science can guide, but it
cannot direct. Wildfires and bark beetles don’t lend
themselves to controlled studies, and the findings don’t
usually point to neat, out-of-the-box solutions.

More than that, even the most undisputed
ecological knowledge is inflected by political,
economic, and social considerations. A set of findings
like Simard’s, however accurate and useful in theory,
may or may not govern management response at the
level of stand, forest, or watershed. Any prescription
will also rely on other research and on-the-ground
experience, and any action will hinge on local
constraints and opportunities.

As JZ posted in his/her comments, I think this piece by Keeley in 2009 explains better why people seem to be partially confused just by the terminology.

In the same set of comments, Larry said:

Additionally, the fire folks don’t like to address the issues of re-burn, which often results in more actual damage than a fire burning in green lodgepole. The damages totaled up for fires burning in green trees often doesn’t include the probability of a re-burn. In dry forests, the remaining fuels from a fire just sit there, until the next inevitable fire incinerates everything in its path. Even fire-adapted species have their limits of fire survival.

I, too, have seen this; near Hells Canyon, burned area with jack-strawed dead lodgepole and lodgepole coming back through the dead trees, another burn of the jack-strawed dead, and the young lodgepole are toast, with few or no nearby seed trees.

But for those who just can’t help getting involved in the fires and bb’s debate, here is another paper that recently came out that specifically examines the areas of agreement and disagreement.

Here’s the abstract

Abstract:

Millions of trees killed by bark beetles in western North America have raised concerns about subsequent
wildfire, but studies have reported a range of conclusions, often seemingly contradictory, about effects on fuels and wildfire. In this study, we reviewed and synthesized the published literature on modifications to fuels and fire characteristics following beetle-caused tree mortality. We found 39 studies addressing this topic with a variety of methods including fuels measurements, fire behavior simulations, an experiment, and observations of fire occurrence, severity, or frequency. From these publications, we developed a conceptual framework describing expected changes of fuels and fire behavior. Some characteristics of fuels and fire are enhanced following outbreaks and others are unchanged or diminished, with time since outbreak a key factor influencing changes. We also quantified areas of higher and lower confidence in our framework based on the number of studies addressing a particular area as well as agreement among studies. The published literature agrees about responses in many conditions, including fuels measurements and changes in stands with longer times since outbreak, and so we assigned higher confidence to our conceptual framework for these conditions. Disagreement or gaps in knowledge exist in several conditions, particularly in early post outbreak phases and crown fire behavior responses, leading to low confidence in our framework in these areas and highlighting the need for future research. Our findings resolved some of the controversy about effects of bark beetles on fire through more specificity about time since outbreak and fuels or fire characteristic. Recognition of the type of study question was also important in resolving controversy: some publications assessed whether beetle-caused tree mortality caused differences relative to unattacked locations, whereas other publications assessed differences relative to other drivers of wildfire such as climate. However, some disagreement among studies remained. Given the large areas of recent bark beetle and wildfire disturbances and expected effects of climate change, land and fire managers need more confidence in key areas when making decisions about treatments to reduce future fire hazard and when fighting fires.

Here’s the paper. I do like the fact that they attempt to make sense out of the different studies and approaches, from a scientific point of view. But I am not so clear on the utility of any of it toward management or policy other than improving fire behavior models. Perhaps we could discuss this further here?