Sunday, June 21, 2009
TESIMONY MOUNTAIN PINE BEETLES
TESTIMONY OF GEORGE WUERTHNER June 19, 2009
Representative Raul Grijalva, Chair
House Subcommittee on National Parks, Forests and Public Lands
Representative Grace Napolitano, Chair
House Subcommittee on Water and Power
Joint Oversight Hearing on "Mountain Pine Beetle: Strategies for Protecting the West”
Dear Representatives Napolitano and Grijalva:
Thank you for allowing me to provide testimony on the mountain pine beetle issues in the western United States. I believe I can bring an ecological perspective to the concerns and I ask that my comments be submitted as part of the hearing record.
First let me introduce myself. I have lived in a number of western states either for school or work. These states include Wyoming, California, Idaho, Montana, Alaska, and Oregon and have visited many others in the course of my work which I will discuss below.
I attended the U of Montana in Missoula for my undergraduate degrees in wildlife and botany, and was enrolled in three separate graduate programs at Montana State University, University of California, Santa Cruz and the U of Oregon.
For quite a few years after leaving academia, I earned my living as a writer and photographer and have published 34 books covering national parks, conservation history, geography, environmental and ecological topics. Two of particular relevance to the topic of pine beetles and wildfire issues are Yellowstone—the Fires of Change, and Wildfire: A Century of Failed Forest Policy.
In researching these books I have had the luxury of traveling extensively across the West to view the aftermath of major wildfires, and the time to read the latest scientific literature related to wildfires, beetles, and other issues. Indeed, at one time or another I have visited every national forest in the West, which, along with my ecological training, gives me a geographical perspective few can provide.
I will address some of the common misconceptions and provide some alternative viewpoints on specific issues. I encourage you to view a recent powerpoint talk I gave that covers many of the major points I will make below.
I would also encourage you to review the paper by Romme el al.
Recent Forest Insect Outbreaks and Fire Risk in Colorado Forests: A Brief Synthesis of Relevant Research for a good overview of beetle ecology and relationship to wildfire. http://126.96.36.199/search?q=cache:JDj5CMoOWjoJ:www.cfri.colostate.edu/docs/cfri_insect.pdf+pine+beetles+romme+Colorado&cd=19&hl=en&ct=clnk&gl=us
I want to highlight a few of their major points here.
First they conclude that: “There is no evidence to support the idea that current levels of bark beetle or defoliator activity are unnaturally high. Similar outbreaks have occurred in the past.”
Second, the idea that dense stands of trees are a consequence of fire suppression is very dependent on the forest type. Higher elevation forests are naturally dense and have not changed significantly due to fire suppression or any other human activities.
Finally, their concluding remarks are worth keeping in mind. They state: “Although it is widely believed that insect outbreaks set the stage for severe forest fires, the few scientific studies that support this idea report a very small effect, and other studies have found no relationship between insect outbreaks and subsequent fire activity.”
And they go on to say … bark beetle outbreaks actually may reduce fire risk in some lodgepole pine forests once the dead needles fall from the trees.”
I will elaborate on all these points below.
Let me start my testimony by suggesting that many of the phrases and words used to describe natural ecological processes like episodic pine beetle events and wildfire are pejorative in tone. We heard a lot of people testifying in this hearing that pine beetles were destroying the forests and/or wildfires were catastrophic and so forth. From the perspective of human values, these words might resonate—certainly if a wildfire burns down someone’s home, it is a devastating experience. However, it is less clear that these terms are appropriate in describing natural ecological events like pine beetle events or large blazes. (See my comments on this in Wildfire: A Century of Failed Forest Policy or Rocca and Romme (2009).
Indeed, pine beetle events, wildfire, and killing droughts are natural ecological processes that are critical to the maintenance of forest ecosystems. To the degree possible, I try to avoid using words with regards to wildfire and beetles such as “destroyed”, “damaged” “unhealthy”, and so on.
As we shall see later in my testimony, dead trees may be more important to the long term “health” and sustainability of forest ecosystems than live trees. There are even some ecologists who believe we do not have enough dead trees to sustain forest ecosystems.
As many of those testifying alluded to, climate/weather may be a big factor in current beetle population increases as well as wildfire size and occurrence (Meyer and Pierce 2003; Whitlock 2004, Westerling, et. al. 2006, Heyerdahl,E. et al. 2008). As has been noted warm winters tends to increase survival of pine beetle allowing their populations to grow rapidly.
Warmer summer temperatures, combined with drought, increases tree vulnerability to beetles, and is a key ingredient in wildfire spread. The importance of climate and large scale oceanic influences on wildfire are obvious from this graph below has the Pacific Decadal Oscillation superimposed over the acreage burned annually by wildfire.
Source: Dave Peterson USFS
This graph shows how the Pacific Decadal Oscillation may have affected wildfires. Cool, moist weather in the 1945s-1980s would have limited fire ignitions and spread. This is the same period that we attribute fuel build up to “effective” fire suppression. But it’s just possible that the conditions were not favorable for fire spread, thus the influence of fire suppression may be exaggerated and overrated.
There several messages to take home from this graph.
The first is when it’s cool and moist, fires don’t spread. It doesn’t matter how much fuel you have, you still won’t get a big blaze. Most fires go out without burning more than a few acres. To illustrate this point, think about the rainforests found in the Coast Ranges of Oregon and Washington. There’s more “fuel” sitting on the ground in those forests than you will find any place in the Rockies but in most years there are no fires. Why? Because the forest is too wet and cool to burn well.
Take home point: Fuels alone do not necessarily lead to massive fires. Thus the fact that pine beetles are killing lots of trees does not, in itself, portend large wildfires.
The key ingredients in all large fires are long term drought, low humidity, high temperatures and most importantly wind. In the absence of these factors, you might get an ignition, but the fire will remain small and likely go out quickly. The mere presence of fuel does not imply that you will have a major wildfire. Since the probability of these climatic/weather factors converging on the same geographic point at the same time is very low, not surprisingly large blazes (pejoratively called catastrophic) are relatively infrequent and rare events.
The interpretation that fire suppression is largely responsible for “dense” tree stands is also being challenged. First in some tree species like lodgepole pine and high elevation spruce-fir forests, recruitment after fires and/or insects tends to create even aged dense stands. Thus it is not “fire suppression” that has created dense forests and these forests are not “overstocked” but display the exact kind of tree age and density that occurred historically.
But more intriguing idea that is getting some traction is that periodic moist, cool periods may also lead to high rates of seedling germination and survival leading to episodic events of tree establishment. In other words, favorable weather for tree survival may be as responsible for “dense” tree stands in some tree species such as ponderosa pine as much as fire suppression (Brown and Wu 2005).
BEETLE KILL DOES NOT NECESSARILY LEAD TO GREATER FIRE SEVERITY OR SPREAD.
A common misconception is that dead trees will increase fire hazard. For instance, one study on beetles and wildfire occurrence that span the last 2500 years, found little correlation between wildfire and beetle events (Berg and Anderson 2006).
Another study (Lynch 2006) in Yellowstone on recently beetle killed lodgepole pine found that susceptibility to wildfire was not necessarily increased, though an earlier beetle event did appear to increase fire occurrence (the reasons are not due to dead trees, however, as I will explain below). Similar findings were reported for subalpine forests elsewhere in the Rockies (Bebi et al. 2003, Schoennagel et al. 2004, Biger et al 2005).
After a beetle event, there appears to be significant variability in fire susceptibility of forests that varies over time—assuming you have the prerequisite drought, wind, and low humidity that drives all large fire. Flammability is increased immediately after a tree is killed by beetles in what is known as the “red needle phase.” However, after the passage of one or two winters and the needles and small branches fall from the tree, the flammability goes way down. Thus if there is no ignition in those first few years (which as we noted earlier is very unlikely), the fire risk is significantly reduced.
It is only after the passage of several decades that susceptibility to fire increases, but not as much due to fuels, but as a result of rapid growth of small trees and shrubs that occurs after the forest canopy is opened by beetles. These small trees provide a ladder for flames to reach up into the forest canopy.
Nevertheless, even this period passes as the forest canopy once again closes, reducing forest fire susceptibility for many decades, even hundreds of years. (See Romme et al. 2006)
DEAD TREES DON’T BURN WELL
Another misconception held by many is that dead trees will increase fire hazard. As explained earlier fire hazard varies over time. But it is fine fuels that carry fires, not large boles. We see that easily after a wildfire. What do you see? Lots of snags. The needles and small branches burn off, but the core tree boles remain. One intuitively understands this from camping. When you try to start a campfire, you gather up “kindling” and small branches to start a fire. If you pile up a bunch of large logs and try to light it, you will likely get nothing for your efforts.
So while dead trees may not increase fire hazard, in reality the presence of green trees may. So in effect the large occurrence of dead trees killed by beetles may actually be reducing the fire hazard for nearby communities.
UNDER SOME CONDITIONS GREEN TREES DO BURN WELL
Let me explain. Green trees are often more flammable than dead trees, especially compared to dead trees (snags) where the needles and small branches are gone. The reason has to do with fine fuels. A living tree has a lot of fine fuels in the form of needles, branches, etc., plus at least for many conifer species, the needles and branches are full of flammable resins. Under drought conditions the internal moisture of these living trees often drops to very low levels. In Yellowstone NP during the 1988 fires, the internal moisture content of green trees was reported to drop below that of kiln dried lumber. Under such conditions of low humidity, drought, and high temperatures, combined with high winds, some green trees with high resin content will burn exceedingly well. (Bunting 1983, Perry 1995)
THINNING AND LOGGING MAY NOT REDUCE FIRE HAZARD
There’s a natural assumption that logging, by removing fuels, will reduce fire hazard. However, the evidence for this is inconclusive at best. There are examples of where thinning appears to have slowed the spread of fires and increased the ability of trees to survive stresses like beetles, drought, and fire (Youngblood et al. 2009), and in some cases reduce fire severity, but fires were not necessarily stopped or controlled as a result of fuel treatments (Pollet and Omi. 2002).
There as many examples of fires racing through previously thinned or logged stands. Indeed, logging can actually increase the likelihood of fire spread by opening up the forest to increased solar radiation and drying. Wind penetration is also increased by thinning. Wind increases drying of fuels, and pushes flames through a forest.
Though fuel treatments may appear to reduce fire spread and severity under “moderate” fire conditions, under severe climatic/weather conditions, particularly with high winds, fuel treatments do not appear to have significant influence on fire spread.
Fuel treatments could even create a false sense of security, much as the levees in New Orleans created for residents. Just as the Mississippi levees were breached when confronted by a category five hurricane, forests with fuel reduction treatments are often “breached” by wildfire under the equivalent of a “hurricane” force wildfire with high winds, low humidity and high temperatures.
DENSE TREE STANDS HAVE SOME VALUES AS WELL
The presumption that thinning forests is always a positive influence on forest ecosystems can be challenged as well. Trees growing under dense conditions tend to have tighter growth rings and are by nature stronger, and more resistant to decay as well. This has important implications for the long term biomass residency time of dead and down logs on the forest floor. Also there is some evidence to suggest that dense forests may inhibit fires due to greater shade and moisture—for instance on the Biscuit Fire in Oregon, dense forest stands tended to burn less severely than more open stands.
FUEL TREATMENTS CAN INCREASE FIRE HAZARD
Thinning, by creating more surface fuels, can increase fire hazard. Unless such surface fuels are removed, a subsequent fire can burn more severely. Thinning, combined with prescribed burning to remove surface fuels is often the most effective treatment, however, burning often does not follow thinning projects.
Furthermore, the effectiveness any fuel reduction treatment declines over time. Typically within 10-20 years, fuel loadings often approach pre treatment levels, thus thinning requires continual maintenance. This is one reason why thinning, if it is used, should be focused on the areas immediately adjacent to communities. Unfortunately, most FS fuel treatments so far are located well beyond that zone. According to a recent review of 44,000 fuel treatments implemented under the National Fire Plan only 3% were in the Wildlands Urban Interface (Schoennagel et al. 2009).
DEAD TREES ECOLOGICALLY IMPORTANT
One of the assumptions implicit in much of the angst over beetle events are the fact that many believe beetles “destroys” the forest. In reality, dead trees may be more important to forest ecosystems than live trees. Dead trees are biological legacies that are critical to ecosystem function. For a short overview see my articles in Forest Magazine Let us praise and keep the dead. http://www.fseee.org/forestmag/1102wuer.shtml
Dead trees serve many functions in the forest ecosystem and their removal can jeopardize future ecosystem sustainability (see Hutto 2006). Dead trees are a reinvestment in the next forest stand. For instance, one study found that 2/3 of all species depend on dead trees at some point in their life. Most of us are aware of the use of dead trees by woodpeckers, but up to 45% of all bird species use dead trees for roosting, feeding and nesting. Other species from amphibians to mammals depend on dead trees as well. Dead trees are important for invertebrates as well.
For example, ants are among the most important invertebrates in forest ecosystems, responsible for protecting trees from other insects to transporting and planting seeds of some flower species. Plus important pollinators like bees and wasps also utilize dead trees. Another study found that lichens were more abundant on dead trees and some species were solely dependent on dead trees for their habitat. And when dead trees fall into streams, they provide much of the habitat for aquatic ecosystems. Indeed, the studies to date do not show any upper limits on the value of dead trees in aquatic ecosystem. In short, the more dead trees, the better for fish and other aquatic life. There are even new studies that show that beetle outbreaks create higher biodiversity (Muller et el. 2008) and beetles may be a “keystone” species in some forest ecosystems.
FOREST ECOSYSTEMS NEED LARGE BLAZES
Even if thinning were able to slow or prevent fires, such a policy would not be desirable. The vast majority of fires burn a very small acreage—most ignitions burn less than ten acres. The bulk of all acreage charred by fires is the result of a handful of blazes annually. If indeed one believes that fires are ecologically important to forest ecosystems, than we have to learn to tolerate large blazes since they are the only fires that do significant ecological work. For more on the ecological need for large blazes see my chapter in Wildfire Logging and Wildfires—Ecological Differences and the need to Preserve Large Blazes (http://books.google.com/books?id=tnW7iYyp2wYC&pg=PA178&lpg=PA178&dq=wuerthner+on+wildfire&source=bl&ots=oB)
It’s important to note that fires do not consume all biomass. Most fires leave a significant amount of dead wood on the site. This wood acts as a carbon storage mechanism. Indeed, charcoal resulting from wildfires stores carbon for thousands of years, and considerably more carbon than is released by combustion. One could argue we need more wildfires, not less, to store carbon in the soil.
LOGGING NOT BENIGN
When we are considering any management schemes, we must always weigh the presumed benefits against the costs. There is no evidence that logging “improves” the forest ecosystem except by using very narrow definitions of “improvement”. In the long term, logging always is a negative impact if all costs are considered. Thus we should attempt to minimize logging impacts to as small an area as possible.
What is seldom articulated by advocates of fuel treatments and other active management are the real ecological and economic costs of such management. For instance, most fuel management (thinning) involves use of logging roads which are notorious for causing sedimentation, and causing disturbance to wildlife. Logging roads by cutting across slopes interrupt water drainage and hydrology of a watershed. Logging equipment and roads spreads weeds and compact soils (Gelbard and Belnap 2003). (Entire books have been written about the impacts of roads, but for short overviews see Foreman and Alexander 1998 and Trumbulak and Frissell 2000)
Removal of dead and/or live trees can affect forest biomass, which in turn may affect things like watershed integrity and aquatic ecosystems. Disturbance of soils can increase the release of carbon. Logging fragments wildlife habitat. And we should not forget the carbon used in transporting trees to biomass converters or sawmills is yet another release of carbon.
In addition, foresters have no idea which trees will be best suited genetically for survival under changing climatic conditions. It’s possible that the very trees that foresters will choose to remove are those that are best able to cope with ecosystem and climatic variability. Letting nature “choose” which trees live or die is the only way to ensure the long term health and resiliency of the forest ecosystem.
Despite self interested assurances from the timber industry, logging is not an ecological analogue for wildfire (See G. Wuerthner 2004 Logging and Wildfire Ecological Differences) and substantially alters forest ecosystem function and ecological processes.
REDUCING HOUSING FLAMMABILITY FAR MORE COST EFFECTIVE
Restricting construction of homes in fire prone areas is a key way to address human safety and fire-fighting costs. But for those homes already in fire prone landscapes, by far the most cost-effective way to reduce losses to wildfire is by reducing the flammability of homes. Removal of flammable materials for 100-200 feet from homes is all that is required to vastly improve the chances that any structure will survive a major wildfire. Jack Cohen at the Missoula fire lab has written a lot about this topic (Cohen 2000). But mandatory metal roofs and a few other modifications to homes can go a long ways towards reducing vulnerability to wildfires at far less cost than attempting to protect communities by widespread logging/thinning fuel treatments.
FINAL THOUGHTS AND SOLUTIONS
There are a number of major points worth reiterating here. First, beetle and wildfire events are desirable and important ecological processes that sustain, not destroy, forest ecosystems. As a society, we should be striving to find ways to maintain these important processes. Rather than viewing such events as a “negative” , we need to find ways to “live” with such natural and ecologically important processes.
Second, the scientific evidence that actually shows fuel treatments can prevent large insect and wildfires is inconclusive. It appears that under severe climatic/weather conditions, these natural processes (beetles and wildfire) are not significantly influenced by treatments. Plus even under less than severe conditions, fuel treatment effectiveness declines rapidly and may even increase fire hazard. In any event, since the large wildfires and insect events are the only ones that we are concerned about, this raises important questions about the wisdom of applying fuel treatments across the landscape.
Third, forest management is not benign. We should limit forest manipulation to as small an area as possible.
Fourth, the majority of fire hazard is located on private lands (see Schoennagel, T. 2009) for a review on this. Any fuel treatments should be focused on the private lands where it will do the greatest good. Furthermore, by focusing strategic attention to these lands where existing roads create easy access for treatment as well as follow up maintenance, the cost-benefits are maximized.
Fifth, keeping people from building homes in vulnerable locations is another key factor. Just as we discourage people from building homes in the flood plain of a river, we ought to discourage people from constructing homes in the “fire plain”. We are not hapless victims.
POB 719, Richmond, VT 05477
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