Post Fire Logging–a bad deal for forest ecosystems

A new publication titled Post Fire logging reduces surface woody fuels up to four decades following wildfire was published in Forest Ecology and Management this week. You can find the article here:

The research will undoubtedly be used by pro logging advocates to justify more post fire logging under the guise that it will prevent or reduce future severe fires–which is the conclusion of the study for a specific short period of perhaps 10-20 years.

A couple of points to keep in mind.

Keep in mind this study was done by the Forest Service researchers and have failed to put their research into an ecological context.

Their starting assumption is that “Post-fire logging may provide an economical way to expand the scope of restoration-based fuel reduction treatments, reduce the threat of future high-severity wildfires, and improve future forest resiliency to fire in dry coniferous forests.”

This assumption is not necessarily a given in my view. I do not want to improve forest resilience to fire because I do not want to reduce future high severity fires and I believe we already have too few fires, and not enough large fires burning. And we definitely do not have enough snags, down wood, etc. in our forested ecosystems due to past logging practices. So the starting goal of this paper, I believe is not ecologically valid.

It is like reading a paper by a Fish and Game department saying we can reduce the impact of wolves on elk populations by shooting wolves. I would not want to reduce the impact of wolves. And if wolves cause elk numbers to drop, then so be it. Who am I to say what the right number of elk or wolves is?

First, and most important thing to remember is fuel loads does not equal a fire. Many people are going to use this study to justify post fire logging, but fires require far more than fuel. And in particular, the kinds of conditions that will burn snags and down logs after a fire are extremely rare.

Furthermore, post fire logging, even according to this study, INCREASES fuels for five years or more. We’ve known this for a long time because it puts more fuels on the ground. But these fuels tend to be the smaller more burnable branches, and other things like flashy fuels like needles. In other words they are the fuels that sustain most fires.

So while small fuels are increased by logging, the larger fuels which would result if left unlogged are far more difficult to ignite.

Then over time you have snags falling over. These tend to be the larger fuels–what they call the 1000 hour fuels. These are the bigger trees. These do not burn readily. They can only burn under the most intense severe fire conditions. Even in most fires, you will find that the majority of these larger fuels do not burn much at all. That is why you have a lot of burnt logs in a post fire situation. The larger logs require smaller fuels under them to sustain a burning logs. Think of a campfire–if you try to ignite a large log, you can’t get it to burn under you push small fuels under it and get it to burn. And once those small fuels are gone, the larger log tends to stop burning.

It only under severe fire conditions that you can get logs to burn. Under such conditions, wind, etc. negates the influence of fuels on fire spread. It becomes a climate driven fire. However, these conditions are rare. This brings up the second point.

Second, what this study measures is fuels on the ground. However, just because you have fuels doesn’t mean you will have a fire.

There is no attempt to determine the probability when a fire will encounter the logged area. The window, according to this study is about years 10-20. During that time the unlogged forest has slightly more likelihood of burning. But what are the chances or probability that a fire (burning under severe fire conditions) will encounter that logged area.

Remember it takes severe fire conditions to ignite and sustain a fire in larger fuels. Well the probability is almost zero. Not quite, but very low.

The point that this reported marginal decline in probability of reburn is measured during the post-fire window when the probability of fire reoccurring is already the absolute lowest it will be at any time in the fire cycle.  So it’s a tiny reduction in what is already a negligible probability event

Third this study acknowledges the importance of down wood/dead tree pulses created by large wildfires. That is a critical idea to keep in mind. We need these pulses of wood for the forest ecosystem health.

Post fire logging contributes to a loss of biomass and woody debris and its ecological importance. The premise again is the FS knee jerk reaction to fires. Oh, we don’t’ want big fires. When in fact we need the larger fires to create lots of wood debris for ecosystem purposes. Removal of all these snags has significant ecological negative effects. It removes the current stand of snags (woodpecker/cavity nesting habitat) and future down wood for amphibians, insects, etc. They don’t’ evaluate this or give any serious discussion to the importance of woody  debris to forest ecosystems.

For instance, I know of one study which showed that fallen logs concentrated water at the ends of the logs. This increased the survival and growth of seedlings. Therefore, helped in the restoration of the green forest. Logs and snags also act as snow fences slowing wind-blown snow and allowing more moisture in the forest. Snags also provide shade. These help to moderate the site conditions which after a fire are typically harsh. This allows for better forest regeneration.

The study of course is only about fuels. But fuels are not the only thing to consider. We know the second highest biodiversity is found in severe wildfires. Eliminating or reducing the opportunities for future fires is not good for the forest ecosystem. There are many species that live in fear of green forests. They are recovering from forest fire protection and green forests. They need the post fire environment.

Fourth, bear in mind that these results were only for dry forest ecosystems dominated by Doug fir and ponderosa pine. You need to keep in mind that the majority of mixed and high severity fires occur in the higher elevation forests and/or shrub ecosystems dominated by lodgepole pine, subalpine fir, aspen, western larch, chaparral, etc.

Even within the Doug fir and ponderosa pine forests there is growing evidence that mixed and high severity fires occur and may even be the norm in some places (for instance that has been demonstrated in the Front Range of Colorado). So what we have is a study that does not apply to most of the forested/shrub ecosystems of the West. But I am certain that people who are logging advocates will try to suggest it should apply everywhere.

Firth, post fire logging loses even more money than green tree logging because the FS assumes the trees have lower value. As a result, the taxpayer is funding all these logging projects. The question becomes is it a wise use of funding.

In short be prepared to hear logging advocates suggest that post fire logging will benefit the forest ecosystem. In reality logging degrades forests. Unfortunately this paper may provide support for the continued impoverishment of our forested ecosystems.



, ,




  1. Larry K Avatar
    Larry K

    I really enjoy reading George’s ecosystem explanations, particularly his gospel about fire. Such complex discussions condensed down to my comprehension level. In this article I saw a teaching jewel when he compared trying to light a big log for a campfire without a supply of tinder. Every boy scout can relate to trying to short cut getting a fire started by not taking the time to supply enough tinder and starting with too large of fuel. My grandsons are going to get the lab version of that concept along with the rest of his points in his essay. Thanks again George Wuerthner!

  2. Gary Humbard Avatar
    Gary Humbard

    Where to begin. First the author believes we have too few fires, and not enough large fires burning. The author is getting his wish as the western U.S. and in a majority of ecoregions, there are significant, increasing trends in the number of large fires and/or total large fire area per year.

    There is no question that past logging practices have removed sufficient quantities of snags and down wood in our forested ecosystems. However, today harvesting practices on federal land must retain adequate amounts of snags and down wood to meet the needs of numerous wildlife species (i.e. woodpeckers, owls, reptiles and even slugs).

    True, fuel loads do not equal a fire. For a fire to burn it takes heat, air and fuel. The ONLY CONTOL we have is to the fuels and given equal weather conditions, reducing total fuels will reduce fire severity, and thus reduce the likelihood of large fires.

    Post fire logging will result in a short term increase of fuels, however since these fuels are typically small burnable branches and needles, they decompose (soil building process) much sooner than larger fuels and within five years the fire hazard has significantly decreased.

    This purpose of this study was NOT to evaluate the negative effects of the removal of snags and down wood, but I can assure you the federal agencies must meet stringent requirements (reserving sufficient snags and down wood) in addressing wildlife habitat requirements when proposing salvage sales.

    The second highest biodiversity is found in severe wildfires. Eliminating or reducing the opportunities for future fires is not good for the forest ecosystem. In the Pacific Northwest, a large percentage of federal land is set aside for the protection of not only the northern spotted owl, but listed fish, plants and numerous wildlife species. I agree that timber salvage should only occur on those lands designated for timber production and to my knowledge rarely occurs on lands set-aside for natural disturbances. By removing a portion of the burned trees within the lands designated for timber production, there are economic benefits to the local economy and to the public. To not remove the burned trees while they have a value for lumber would be a violation of the current forest management plan and thus be irresponsible in respect to the federal managers.

    Considering the drought and warming of the climate in the west, the increase in large fires, the requirements to retain adequate amounts of snags and down wood when timber salvage does occur, it seems prudent to allow post salvage logging to take place on those lands designated for timber production and in other special situations (i.e. close to communities).

    1. Larry K Avatar
      Larry K

      I think one of the important points made in George’s essay is prediction that advocates for increasing logging quotas will use the study as a wedge thus having the quotas fall in their direction. I wonder how many snags/acre there are in a genuine old growth like northwest national parks? How does that number compare with the quota left in accordance with federal logging requirements? I will stick my neck out and say I bet old snags in an old growth forest are more site valued having been chosen by the ecosystem, than those selected to be left in a clearcut. I further think that the real message here is to recognize that no matter what level of science we choose to consider will come up short when compared to natural ecosystem functions considering the tried and proven of that system over millions of years. How come we suddenly have smarts developed in the last 100 years or less that we think is superior to a system millions of years old? We harvest timber, I get that, but I think we should not be so foolish as to say by using our “harvest” methods we are making the ecosystem better. Let’s at least speak ecoese.

      1. Ed Loosli Avatar
        Ed Loosli

        Larry K:
        You have spoken words of wisdom – Nicely said…+1

      2. Greg Stratton Avatar
        Greg Stratton

        It is interesting that the knowledge from the last 100 years is not adequate. The system that is millions of years old, contains very few trees over 400 years old and had there not been fire suppression for the last 100 years, there would be even fewer. There are no true intact old growth ecosystems, man has changed and influenced all of them, if not by harvest, then by fire suppression. The idea that we can let an ecosystem “function” naturally after centuries of intervention may be well meaning, but is bordering on ignorance. The current biomass levels are not natural and it is an ignorance of fire effect and behavior to think that allowing more large fires in this unnatural state, will be “natural”. Who is to say that civilization isn’t part of a functioning ecosystem? European civilization has managed their ecosystems for centuries. Native Americans managed these ecosystems to a limited degree for thousands of years. Who is to say that they wouldn’t have done more if they had had the technology? It doesn’t take rocket science or even science to look around and see the results of just 25 years of foolishness. But if you want to be scientific, study the increase of money into environmental groups and the increase in the number of salaries, over the median income, within environmental groups. Environmentalism has become an industry and within this industry is a growing disparity of wealth. To speak ecoese might be another way to deflect the reality of what has been created.

  3. rork Avatar

    My thanks too.
    In the eyes of most of my neighbors, my woods is unruly, cause I didn’t “clean up” most of the big trees the tornado sent to earth, and logs that fell on my “yard” got moved to the woods too. By such means I “wasted” the wood. (I actually did give a bunch to worthy causes though.) The neighbor on one side has taken to mowing between his now thinner front red oaks – so clean and park-like, you know. I have a zillion blue-spotted salamanders, and this year, nesting pileated woodpeckers. Northern King snakes like it too. Maybe it was George I first saw saying about dead trees that they were only now at their most valuable – thanks for the lessons.

    1. Larry K Avatar
      Larry K

      I would give most anything to have a pair of nesting pileated. I have a pair in the neighborhood that come back each year but have never found their nest tree. They are kind enough to hammer on a few snags on my place however. Haven’t seen them yet this year and they are overdue. Hope they are ok.

  4. Greg S Avatar
    Greg S

    It is relevant to say “…. And if wolves cause elk numbers to drop, then so be it. Who am I to say what the right number of elk or wolves is?” George should take the same attitude towards fire discussions.
    After spending 35 years fighting & managing wildfires, I find fault with numerous statements given as fact.
    Large fuels – 100 & 1000 hr do actually sustain wildfires, while the 1 & 10 hr fuels carry or cause increased rates of fire spread in most cases, but the smaller fuels lack the intensity of larger fuels. One of the exceptions to this are when snags are involved. Fire will run up the snags even under mild conditions finding smaller dead branches to consume and create embers that since they are elevated will drift away from the snag as they fall. In instances of windy conditions snags can contribute to fire spread in the form of spot fires up to 1 mile away. This happens even though the interior of the larger fuels may still have moisture levels exceeding 20%.
    Once an area is logged there is an increase in fine fuels that will increase the rate of spread for any fire occurring in the area for 2-5 years but the intensity of these fires and the flame lengths are greatly reduced due to the reduction of large fuels and aerial fuels. The fire behavior is much more manageable in harvested areas when compared to unharvested burned areas littered with standing snags and primed with large fuel from fallen trees.
    This is just the tip of the iceberg that is floating George’s ecosystem explanations concerning wildfire. His obvious bent against logging is no better than those he accuses of doing the same to justify logging. True science based on current conditions and previous management, such as fire exclusion, would prove his ideas disastrous in both moist and dry forest environments of today.