Bozeman Watershed Project Based on Flawed Assumptions


Stream in Bozeman Watershed in Gallatin Range where thinning is proposed to reduce wildfire. Photo George Wuerthner


The Montana Forest Action Plan recently awarded funding to the Bozeman Watershed logging project.

Flawed assumptions and science characterize all these state-funded projects. Even though numerous studies have documented that logging/thinning fails to protect homes or reduce fire severity in nearly all instances, the mindless mantra that logging will preclude large fires continues unabated.

  1. Most of the acreage burned annually results from a few blazes burning under “extreme” fire weather conditions. Under these conditions, the climatic/weather conditions trump fuels as the primary factor in fire spread.
  2. Extreme fire weather includes drought, low humidity, high temperatures, but the most important factor is wind. Wind drives flames through thinned forest stands. Indeed, thinning, by opening the forest dry fuels, as well as increases in wind penetration.
  3. These changes in forest structure are one reason why research has demonstrated that forests under “active management,” including thinning, prescribed burns, and other manipulations, actually burn at higher severity than protected landscapes like wilderness or parks where such management is prohibited.
  4. Embers are transported by wind several miles ahead of any fire, ignite new blazes. This is why thinning, and other “active management” fails to halt fire.
  5. What burns in a forest fire is not tree boles but the fine fuels like needles, cones, grass, and shrubs. That is why we have snags left after a blaze.
  6. Thinning and doing prescribed burns reduces competition for water and nutrients and stimulates plant growth of mostly fine fuels like grass, shrubs, and small trees, increasing the kinds of plant growth that support wildfire.
  7. One cannot predict where a fire will occur. Scientific studies have demonstrated that few blazes encounter thinned forest stands—usually less than 1%. Consequently, most thinning and logging have no benefit in protecting homes reducing fire spread.

    Erosion from logging road, thinning project, Montana
  8. Logging/thinning are not benign. They have collateral damage, including the spread of weeds, disturbance of wildlife, chronic sedimentation from logging roads that damage streams, removal of biomass and structure from the forest that is essential wildlife habitat.
  9. Most human-caused fires begin along roads, thus an increase in logging roads contributes to higher fire ignitions.
  10. Ironically logging also contributes to greenhouse gas emissions that are the factor behind the drought and rising temperatures driving wildfires. For example, in Oregon, 35% of the state’s s GHG emissions are due to logging.
  11. Leaving forests intact preserve carbon. Even burnt forests retain most of their carbon—all those snags left after a high severity blaze are carbon. Logging removes this carbon, and processing wood releases much of this carbon now.
  12. As fire scientist Jack Cohen has noted, it is treating the immediate area around homes that will protect structures. We do this by starting at the house and working outwards. Removal of burnable materials from the immediate area around the home, installing metal or other non-flammable roofs, and putting shutters on windows, among the strategies that work to protect homes even from high severity wind-driven blazes.
  13. Zoning to limit home construction in the “fire plain” is also necessary—the rising costs of firefighting are due to efforts to protect homes in the Wildlands Urban Interface.

As Albert Einstein said so succinctly, “The definition of insanity is doing the same thing over and over again and expecting different results.”






  1. STG Avatar

    A disconnect exists between policy and science. Thanks for this science-based, informed post.

  2. Herb Hammond Avatar
    Herb Hammond

    I like George Wuerthner’s take on logging/thinning and fire. I would appreciate him posting the references that he refers to in his article, as this would help broaden the debate about the use of logging to allegedly reduce fire risk. Thank you.

  3. Rhonda Millikin Avatar
    Rhonda Millikin

    Thank you George and Herb for challenging the assumptions in forest prescriptions. I too would appreciate your posting the references George.


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George Wuerthner