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Post a Comment. 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. 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.
Similar outbreaks have occurred in the past. 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. However, it is less clear that these terms are appropriate in describing natural ecological events like pine beetle events or large blazes.
Indeed, pine beetle events, wildfire, and killing droughts are natural ecological processes that are critical to the maintenance of forest ecosystems. There are even some ecologists who believe we do not have enough dead trees to sustain forest ecosystems. 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.
Cool, moist weather in the ss would have limited fire ignitions and spread. There several messages to take home from this graph. 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. 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. 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. A common misconception is that dead trees will increase fire hazard.
For instance, one study on beetles and wildfire occurrence that span the last years, found little correlation between wildfire and beetle events Berg and Anderson Another study Lynch 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. 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. 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. 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.
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.
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. Under drought conditions the internal moisture of these living trees often drops to very low levels. In Yellowstone NP during the 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. 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.
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. Fuel treatments could even create a false sense of security, much as the levees in New Orleans created for residents.
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.
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 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. 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. Dead trees are a reinvestment in the next forest stand. 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. The vast majority of fires burn a very small acreage—most ignitions burn less than ten acres.
As forests die, questionable anxieties thrive
Along with recent high-intensity forest fires, these insect outbreaks are raising concerns about the health of forests across the nation. An independent group of scientists from the Colorado Forest Restoration Institute at Colorado State University, the University of Colorado and the University of Idaho, have reached a consensus about some of the critical ecological information needed for forest management in Colorado. The group developed a report that provides forest managers and policymakers with information about different kinds of insect outbreaks occurring in Colorado forests as a basis for making decisions about how to manage forests that are going through substantial changes. This information is essential, as Colorado recently experienced severe and extensive insect outbreaks.
CFRI COLOSTATE EDU DOCS CFRI_INSECT PDF
Colorado, by Dominik. Obituary for Elaine M. The full report on forest insect, fire risk, is available at Overview. This report is a brief synthesis of the current understanding in of insect outbreaks.