Bark beetle kill leads to more severe fires, right? Well, maybe

  • The 2011 Norton Point Fire in Shoshone National Forest, Wyoming, burned both beetle-damaged and healthy trees.

    Kari Greer and the USDA Forest Service
  • Beetle-killed trees in Colorado's Never Summer Mountains near Gould.

    Kari Greer and the USDA Forest Service
  • Tree mortality in 2011

    U.S. Forest Service, Forest Health Protection, Forest Health Technology Enterprise Team
 

The lodgepole pine and spruce-fir forests of the Intermountain West are reeling under a one-two punch: more frequent and severe wildfires, and an epidemic of tree-killing bark beetles.

Once-green forests are filled with red dying trees and patches of gray dead ones. From a distance, the effect is oddly beautiful. Up close, people often experience a visceral jolt, followed by a sense of alarm: Can't somebody do something?

Steve Currey has fielded his share of anxious phone calls. "A few years ago," he says, "we were under a lot of public pressure to stop the beetles from spreading further." Currey is director of bark beetle operations on the sprawling Medicine Bow-Routt National Forest in Wyoming and Colorado. The outbreak there started in northwestern Colorado in the mid-1990s and moved northeast to central Wyoming. "The beetles aren't killing every tree," Currey says, "but they are killing a majority of mature lodgepole pine, and we've lost half our limber pine, too." More than 116 million acres in the North American Rocky Mountains have been affected. "People are beginning to understand that this thing is too big to stop."

Wildfire and beetle epidemics both have long histories in Western forests. Their patterns have been shaped somewhat by human impacts, but outbreaks, which tend to be infrequent and severe, are driven by larger factors. Scientists believe a warming climate is the main factor behind the West's more frequent severe wildfires, and is also likely amplifying the current bark-beetle epidemic, the most widespread on record. Warmer winters allow beetles to spread into more northerly and high-elevation territory. Beetles reproduce more often during longer warm seasons, and more larvae survive winters.

It might seem that fire and bark beetles are locked in some malevolent feedback loop, with fires inviting beetles to devour weakened trees, and beetles creating fuel for future fires.

But "there were surprisingly little data backing up that conventional wisdom," says Monica Turner, a University of Wisconsin landscape ecologist and coauthor of a much-discussed 2011 study that examined links between beetle epidemics and wildfires in the Greater Yellowstone Ecosystem.

The study's findings -- that beetle attacks don't increase severe-fire risk, and may in fact reduce it as dying trees shed needles -- may sound counterintuitive. But they are in line with more than two decades of research indicating that, while bark beetle epidemics and fire are entwined in complicated ways, one does not necessarily amplify the other.

Yet this recent study -- which used a computer model that simulates fire behavior to predict severe-fire risk based on current conditions, unlike most of the previous research, which looked to historic beetle epidemics and fire patterns to unravel the relationship between the two -- has drawn sharp criticism, particularly from those who manage fires in beetle-killed forests. Turner and her colleagues say that large-scale removal of dead trees -- often proposed to reduce fire risk -- is "probably not needed" in lodgepole forests, which dominate the upper montane and lower subalpine zones of the Rockies. Critics counter that the study's methodology and narrow geographic scope don't justify its sweeping conclusion, and that it shouldn't be interpreted as a broad indictment of salvage logging. This collegial wrangle illuminates how messy -- yet essential -- it is to apply land-management science to management itself. And it raises the question: Should we do something with all that dead wood?

Frank Carroll
Frank Carroll says:
May 15, 2012 02:47 PM
In fairness to every reader you must reveal that the unequivocal fire safety message sent to all fire teams on August 11, 2011, says that we may expect extreme fire behavior when fire danger is moderate in beetle-killed forests across the Rocky Mountains. This safety alert was based on observed conditions. This fact is related to low fuel moisture, solar heating of heavy ground fuels, and intesnse spotting as a result. Do not mistake this for another willy nilly scientific forestry debate. People will die.
Tim Baker
Tim Baker says:
May 24, 2012 02:52 PM
There was a recent article in Forest Science (Hoffman et al., 2012, Numerical Simulation of Crown Fire Hazard Immediately after Bark Beetle-Caused Mortality in Lodgepole Pine Forests. Forest Science 58:178-188) that found results that contradict those reported above by Turner's group (Simard et al., 2011). Of course, part of the problem is in trying to use physics-based process models to figure out what's going on in the real world, but the discussion is interesting nonetheless.

I suspect that Hoffman et al. are closer on what happens in the period immediately after the infestation but the interesting problem is what happens if the fire doesn't occur for 3-5 years after the needles have fallen? As for salvage logging, I think it makes sense where it replaces harvesting live trees but certainly not everywhere simply because of the scale of the problem.
Randy Piper
Randy Piper says:
Mar 04, 2015 01:20 AM
There are certainly some valid points made here, but after trying to put all the pieces of this enormously complex and vast puzzle together by studying every factor I could find that was written and projected over the last 10 years, this seems like yet another study that seems like a ridiculous waste of time and money. Time and money that could be applied to utilization efforts and the protection of our communities, recreation areas and tourism industries, power grids, transportation infrastructure, waterways and water supplies. Wasted money in many ways, for it ignores many other factors and variables that don't even get mentioned by these experts that spend time focusing within such narrow parameters that are not even close to the reality of the big and widely varying picture in the real world! What's the sense of this focus when the trickle down effects, or maybe more accurately flood down effects, are not even taken into account in any way?

If all the pieces are pulled in and the big picture is reviewed, then I believe most of us would come to an overly simple decision that is not anywhere near as simple to implement.
Use more wood - the dead stuff that makes sense first, then live timber - and grow more trees. This is one of the few defenses we have to slow the warming and create value for our future generations.
It is certainly do-able if we applied some of the resources we have given to oil and gas industry while they rake in record profits, or to the big banks that have spent billions to protect the far more vast profits resulting from the theft and fraud they committed at the expense of many throughout the world, and there are many more examples could be brought forth...all the way down to these scores and scores of specialized studies that tell us so little about the big picture.

Let's look at a few things that are ignored in these studies...
What about the trillions of pounds of carbon that will be released by billions of dead trees as they burn and fall down like a monstrous game of pick up sticks over tens of millions of acres on their way to decay? It is projected this massive release over a relatively short period of time will only fuel the warming cycle and increase the drought problem. And how will our forests react so quickly to such massive changes? Will they be able to? There are certainly going to be enormous and impactful changes.

And how are elk and deer going to move through this pick-up-stick landscape? Or will they just move? What about all the other impacts to wildlife? Or recreation and tourism that is so critical as an economic base for so much of the West?

What about the impacts to our water? Far fewer live trees = faster snow melt which creates more erosion and more turbidity, and it also means less water in mid and late summers - all coming at a time when we are experiencing a vast need for more water. Billions and billions of gallons of water is being pumped into fracking wells alone, with largely unknown consequences, and at a time when the world’s population is to swell by over a third by 2050 creating massive increases in consumption. Earth torn up by falling trees massively compounds this.
What about the impacts to our aquatic life?
What about the thousands of miles of power lines running through dead forest?
What about our transportation infrastructure?
What about the fire-fighting costs?
What about the societal costs?
 And we come back to the recreation and tourism dollars…
There is more, but the economic cost is staggering, and the environmental and societal costs are almost beyond comprehension, or even speculation with any accuracy.

There is certainly no magic bullet, but to make intelligent and practical decisions that will hold mostly positive over the long haul, we must look at the big picture and find happy mediums. No one is going to be 100% happy with the actions that should be taken - not the extreme greens that send out as much rhetoric and as many part truths as the corporate and political opposite. Hiring lawyers to tie everything up so no one except the lawyers win is not the answer, and certainly it is not with those on the extreme end of industry with a profits at the expense of all else mind sets. How is it that so few can so greatly affect the many? Is that the democracy our forefathers intended? Doesn't seem likely. Only when the public applies pressure to the politicians will anything change in the scope it is needed.

There certainly is not one answer for all areas, so maybe we should start applying some common sense and bring these varying factors and sciences and studies together to form solutions that are best suited to us, the people of America, and for that matter the world, for we now know that impacts in one part of the world are not silo’d to that location.
Unfortunately, it may take a big burn of millions of acres and the loss of many lives, the clogging of our water supplies, the melt-down of our power lines, the moon-scaping of our soils so nothing can grow through it, and the crush of economic crisis before we get a whole lot smarter. Or will that just result in more studies and knee jerk reactions?

A small percentage of the population is more environmentally or socially conscious and aware than I am, so to be clear, I am certainly not promoting that we raze our forest in a giant clear cut, but common sense utilization through lumber products captures carbon off put - approximately a 1/4 ton per 125 SF of 1" board stock. Biomass use is largely carbon neutral or can even be carbon negative through applications like char and wood fuels by gasification and pyrolysis. And it provides jobs to a rural America that is truly struggling. Perhaps it will even help spread out the population to help create a more sustainable future? And it will help reduce our reliance on fossil fuels. We need them for the foreseeable future so we should get a whole lot smarter about preserving them.

Yes, there are some valid arguments for the carbon off-put and erosion impacts when soil is disturbed, and fossil fuel is used to remove timber, but what the heck do they think is going to happen when an average of 400-600 trees per acre fall down and tear up the soil?

The forest service recently reported that our forests in the West are now off putting more carbon than they are absorbing. Live trees absorb carbon and produce oxygen. We kind of need those things, so though only a part of the solution, we need to use more wood and grow more trees.