Science Attachment #8
Thinning should never be considered
an acceptablepractice on
publicly-ownednational forests
"Logged areas generally showed a strong association with increased rate of spread and flame length (table 5), thereby suggesting that tree harvesting could affect the potential fire behavior within landscapes. Wilson and Dell (1971) describe two main reasons for the fuel and potential fire problems in Pacific Northwest forests and rangelands: fire exclusion has allowed unnatural and hazardous levels of fuels to accumulate, and intensive forest management annually produces high fuel loadings associated with logging residues. As a by-product of clearcutting, thinning, and other tree-removal activities, activity fuels create both short- and long-term fire hazards to ecosystems. The potential rate of spread and intensity of fires associated with recently cut logging residues is high (see for example, Anderson 1982, Maxwell and Ward 1976), especially the first year or two as the material decays. High fire-behavior hazards associated with the residues can extend, however, for many years depending on the tree species (Olson and Fahnestock 1955). Even though these hazards diminish, their influence on fire behavior can linger for up to 30 years in the dry forest ecosystems of eastern Washington and Oregon. Disposal of logging residue using prescribed fires, the most common approach, also has an associated high risk of an escaped wildfire (Deeming 1990). The link between slash fires and escaped wildfires has a history of large conflagrations for Washington and Oregon (Agee 1989, Deeming 1990). “ (Pg. 21)
Huff, Mark H., Roger D. Ottmar, Ernesto Alvarado, Robert E. Vihnanek
John F. Lehmkuhl Paul F. Hessburg, and Richard L. Everett
1995 “Historical and Current Forest Landscapes in Eastern Oregon
and Washington. Part II: Linking Vegetation Characteristics to
Potential Fire Behavior and Related Smoke Production”
USDA Forest Service, General Technical Report PNW-GTR-355
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“Congress should prohibit the use of commercial timber sales and stewardship contracts for hazardous fuels reduction projects. Commercial logging removes the most ecologically valuable, most fire-resistant trees, while leaving behind highly flammable small trees, brush, and logging debris. The use of "goods for services" stewardship contracts also encourages logging larger, more fire-resistant trees in order to make such projects attractive to timber purchasers. The results of such logging are to increase fire risks and fuel hazards, not to reduce them. The financial incentives for abusive logging under the guise of "thinning" must be eliminated.”
Ingalsbee, Timothy Ph.D., “National Fire Plan Implementation:
Forest Service Failing to Protect Forests and Communities”
American Lands Alliance, March 2002
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“The idea of thinning forests may sound like good old common sense, but accomplishing our forest restoration goals through human intervention has other consequences. To thin the forests through mechanical means building roads and disturbing soils, and doing so repeatedly over time to maintain the desired conditions. Forests are complicated communities, not just collections of trees. Thinning removes hiding cover for wildlife, and disrupts natural processes.
Under the Bush Administration, the Forest Service promoted thinning as a way to restore healthy forests and limit both the number and extent of fires in forests. The theory is that if smaller trees are removed, less fuel means that the fires may be cooler and less likely to damage the larger trees. Yet, the answer is not that simple. Forest fires are primarily driven by climate conditions-the best weather for fire is a combination of sustained drought and heavy winds. In these conditions, even thinned forests will burn up and no amount of fire fighting will stop the blaze. On windy days, flames and sparks can be carried long distances, even over treeless areas. For thinning to be effective, trees would have to be a great distance apart with large spaces between tree crowns and all ground cover would need to be removed. This is not most people’s idea of a healthy forest.
Thinning can also remove the canopy and the cool and damp micro climates that these canopies provide on the forest floor. Without sufficient canopy, these forests will become drier from sun exposure and wind speeds will increase.In this way thinning may actually increase both the risk and size of future fires.
Generally speaking, thinning activities seek to space out trees and create a more park-like environment in forests. Although lower-elevation ponderosa groves may fit this fold, many other forests do not. Higher-elevation mixed conifer forests may be quite dense and contain a diversity of tree species that have evolved with fire. To thin these forests is to try to change them into something they are not.”
Luetkehans, Jennifer, Crag Intern
2009, “Ensuring Healthy Forests for Future Generations”
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“Even in forests where frequent, low-severity fires are the rule, the possibility that thinning may have unintended consequences merits careful consideration. Among other things, thinning can open forests to drying winds, making branches and needles even more flammable. It can expose pristine areas to vehicle and foot traffic that compacts soil and facilitates the spread of exotic grasses and weeds. And then there are all the other considerations, ranging from the aesthetic (what a forest should look like after it's thinned) to the practical (what to do with all the small-diameter trees a massive thinning program would generate).”
Nash, J. Madeleine, “Fireproofing The Forests”
Time, Aug. 18, 2003
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“Post-fire reports on individual fires make little or no mentionof excess fuels. Instead, fire scientists agree that droughtis the cause of the severe fires in recent years. This year’s Rodeo-Chedisky Fire, the largest fire in Arizona history, was on heavilymanaged and thinned federal lands, not an untouchedwilderness brimming with excess fuels.”
O’Toole, Randal. “Money to Burn?”
Regulation, Winter 2002 - 2003
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“Intensive thinning, which is a likely component of mechanized fuel treatments (MFT) to reduce fuels, can involve the cutting and yarding of more trees per unit area than conventional logging. This increases the area of soil disturbance from yarding and felling per unit area affected. Therefore, soil damage from intensive thinning is likely to be as great as or greater than that from conventional logging. Based on similar logistical considerations, Geppert et al. (1984) concluded that intensive thinning with ground-based machinery likely causes greater soil damage per unit treatment area than the conventional clearcutting of large trees.” (Pg. 17)
“Vegetation removal activities as part of MFT will increase surface erosion, sediment delivery, and resulting negative impacts on aquatic resources. While most studies of the effect of vegetation removal on sediment delivery have focused on traditional logging practices, these findings are relevant because MFT involves largely the same suite of activities, whether as a matter of thinning, creating fuel breaks, or other types of cutting (e.g. partial removal, group selection, etc.” (Pg. 25)
“Raymond (2004) documented that thinning in the absence of surface fuel treatments increased fire severity in a statistically significant fashion in mixed conifer forests in SW Oregon burned by the 2002 Biscuit fire.” (Pg. 39)
Rhodes, Jonathan J.
2007, “The Watershed Impacts of Forest Treatments to Reduce Fuels and Modify Fire Behavior”
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“Thinning forests without also burning accumulated brush and deadwood may increase forest fire damage rather than reduce it, researchers at the Forest Service reported in two recent studies.”
“The studies show that in forests that have been thinned but not treated with prescribed burning, tree mortality is much greater than in forests that have had thinning and burning and those that have been left alone. Another study, on Blacks Mountain Experimental Forest in Northern California, had similar findings.”
Robbins, Jim, “Studies Find Danger to Forests in Thinning Without Burning”
New York Times, November 14, 2006
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“This brings us to flawed assumption number three. There is a growing body of anecdotal and scientific evidence to suggest that thinning, or fuels management-by whatever euphemism logging is called-does not slow or reduce the likelihood of large blazes. Again, this goes back to the fact that large blazes are primarily a consequence of climatic conditions. You can have a ton of fuels on the ground, but if you don't have the right conditions for a fire to spread, fuels don't matter; it won't burn.
On the other hand, if climatic conditions are severe, with extended drought, high temperatures, low humidity, and most importantly high winds, then fires will burn through all kinds of fuel loadings, including forests with very light fuels. Wildfires will roar through clearcuts, thinned forests, and even naturally thin forest stands with surprising vigor. We have seen many examples of this in recent years, including some of the larger blazes that burned in western Montana this summer. The Jocko Lakes fire by Seeley Lake, Montana, and the Black Cat fire by Frenchtown, Montana are only two of many recent fires that burned through heavily logged and managed forest stands.
In fact, there is some evidence to suggest that thinning the forest can actually acerbate fire spread and intensity. Remember that fires spread quickest and burn hottest under conditions of drought, wind, and high temperatures. When you thin the forest, you open it up to solar radiation which dries out fuel, and increased temperatures result in additional heat stress on trees which respond with greater evaporative transpiration from needles and leaves, further drying soils and wood. Both of these factors increase flammability. And thinning allows the wind to penetrate further into a stand so that even a small 10 mph increase in wind speed can lead to a huge increase in fire spread, since wind increases fire spread exponentially.
In addition, opening up the canopy by thinning increases available sunlight, and the reduced competition for nutrients spurs rapid growth of small trees and fine fuels like grasses, thereby increasing the relative flammability of the forest stand.”
Wuerthner, George “The Beaverhead-Deerlodge Deceit,
Forest Fires, Lies and Chainsaws”
CounterPunch, November 29, 2007