Examining Historical and Current Mixed-Severity Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

The other day I got the following note and link to some new relevant research from Douglas Bevington, author of The Rebirth of Environmentalism: Grassroots Activism and the New Conservation Movement, 1989-2004.  Bevington’s note is shared below with his permission, along with a link to the new study and article. . – mk

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I wanted to let you know about an important new study that was just published by the high-profile science journal PLOS ONE. The article, titled “Examining Historical and Current Mixed-Severity Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America,” was co-authored by 11 scientists from various regions of the western US and Canada.

Their study found that there is extensive evidence from multiple data sources that big, intense forest fires were a natural part of ponderosa pine and mixed-conifer ecosystems prior to modern fire suppression. These findings refute the claims frequently made by logging and biomass advocates that modern mixed-severity forest fires (erroneously called “catastrophic” fires) are an unnatural aberration that should be prevented through more logging (“thinning”) and that more biomass facilities should be built to take the resulting material from the forest.

In contrast to these claims, logging done ostensibly to reduce fire severity now appears to be not only unnecessary, but also potentially detrimental when it is based on erroneous notions about historic forest conditions and fire regimes. These findings have big implications for biomass and forest policy, so I encourage you to take a look at this article.

The full article in PLOS ONE is available here.

Here are a few key points from the abstract and conclusion:

Abstract, p. 1

“There is widespread concern that fire exclusion has led to an unprecedented threat of uncharacteristically severe fires in ponderosa pine and mixed-conifer forests of western North America. These extensive montane forests are considered to be adapted to a low/moderate-severity fire regime that maintained stands of relatively old trees. However, there is increasing recognition from landscape-scale assessments that, prior to any significant effects of fire exclusion, fires and forest structure were more variable in these forests….We compiled landscape-scale evidence of historical fire severity patterns in the ponderosa pine and mixed-conifer forests from published literature sources and stand ages available from the Forest Inventory and Analysis program in the USA. The consensus from this evidence is that the traditional reference conditions of low-severity fire regimes are inaccurate for most forests of western North America….Our findings suggest that ecological management goals that incorporate successional diversity created by fire may support characteristic biodiversity, whereas current attempts to ‘‘restore’’ forests to open, low-severity fire conditions may not align with historical reference conditions in most ponderosa pine and mixed-conifer forests of western North America.”

Conclusion: p. 12

“Our findings suggest a need to recognize mixed-severity fire regimes as the predominant fire regime for most of the ponderosa pine and mixed-conifer forests of western North America….For management, perhaps the most profound implication of this study is that the need for forest ‘‘restoration’’ designed to reduce variation in fire behavior may be much less extensive than implied by many current forest management plans or promoted by recent legislation. Incorporating mixed-severity fire into management goals, and adapting human communities to fire by focusing fire risk reduction activities adjacent to homes, may help maintain characteristic biodiversity, expand opportunities to manage fire for ecological benefits, reduce management costs, and protect human communities.”

34 Comments

  1. Ahhhh! Now I see where Let-Burn fires come in, reproducing and returning damaging, high-intensity wildfires back into our forests, Yep, this destructive “quality” has been missing from our forests since before mankind crossed the Bering land bridge. Using this same line of reasoning, cholera is excellent for the environment, as long as you exclude man’s beneficial impacts. *BIG smirk*

    Seriously, just the mere existence of large and old pines is evidence that American Indians management produced long-lived forests. In today’s world, the old growth stands produced by Indians are being lost to these massive firestorms. I doubt that such forests will return, with a policy of “whatever happens”, which includes arson fires, auto accidents, plane crashes and fireworks.

    • The unspoken thesis here is that without humans, nature is bad. I find that just as disturbing as nature + humans = bad.

      The comment also seems to miss the point that the time period examined by this study includes humans in north america. So, humans AND large trees AND stand replacing fire all co-exist, somehow.

      Fires have been a constant, the biggest threat to large trees is the relatively recent introduction of commercial logging.

      • What about the last 20 years of no old growth harvest and a ban on clearcutting in the Sierra Nevada National Forests???? Your argument vanishes, in a puff of smoke here, Tree! Clearly, the biggest threats to big trees here are bark beetles and wildfires, and nothing you can say can change those facts. When 400 year old trees, in large amounts, are dying in large wildfires, like in the last 20 years, we need to make some changes in how we mitigate drought, in our forests. Oddly enough, the fires of the 60’s through the 80’s were smaller and less destructive than today’s firestorms.

        • The fact that trees are dying in fires does not mean there is a diminishing population of large trees because mature trees are aging across the unburned landscape. The real test is whether the rate of recruitment is greater than or less than the rate of loss. Studies of this sort have been done in western Oregon and it is quite clear that owl habitat is being recruited faster than it is being lost to fire. I am not aware of studies attempting to answer this question in dry pine forests, but they may well exist.

          • Found on the web:
            The Biscuit fire affected 49 of the Siskiyou Forest’s 202 known northern spotted owl territories, including 22 which lay completely within the fire perimeter and another 11 where the nest was within the fire perimeter. Each northern spotted owl territory is 3,400 acres, and biologists rate the quality of individual territories by the percentage that is actually late successional forest at least 160 years old. The benchmark for excellent habitat is 40 percent old growth or more. Before the Biscuit fire, 40 of the 49 territories affected by the flames contained at least 40 percent old growth, said Lee Webb, biologist for the Siskiyou Forest After the fire, only 17 contained at least 40 percent old growth.

            Webb thinks most of the owls survived the fire but many won’t reinhabit territories that no longer offer sufficient food or shelter: With up to 80,000 acres of suitable habitat gone, there might be up to 40 pair that there isn’t suitable habitat for,” he said. “It’s quite a bit at one time. I’d rather see the change more gradual, less disruptive, but I don’t think there’s any vertebrate species that will disappear from the Siskiyou Forest because of the Biscuit fire.”
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            I have pictures from the Biscuit showing near-100% mortality in an old growth stand. I have pictures of an actual “owl circle” there, with just a handful of live trees left in it. Again, you’re showing your ignorance of the differences between nesting habitats and foraging habitats. Two entirely different, polar opposites.

  2. Matt:

    Well it is interesting to learn that my PhD was “erroneously” titled: The Great Fires: Indian Burning and Catastrophic Forest Fire Patterns of the Oregon Coast Range, 1491-1951. I guess my only excuse is that this “important new study” wasn’t available to me when I was doing my research, and I was forced to resort to a dictionary, which typically defines a “catastrophe” as “a violent and sudden change in a feature of the earth.” Which was, of course, a reasonable definition of “catastrophic wildfire” way back when.

    Trust me, forest management and decimated human populations — and NOT fire suppression — have been largely responsible for the recent spate of unusually large wildfires. These atypical and unusual (in their geographic range, general severity, and frequency over time) events are unprecedented in history. “Uncharacteristic” doesn’t do these events justice; although the term is accurate enough, however condescending. The widespread 1902 and 1910 events — which preceded modern firefighting — took place in single years, not over decades. I am guessing that these authors are not/must not be including Indian Burning in their definition of “natural.”

    Reading the abstract was sufficient. I won’t bother reading the paper unless I am paid to review it. Also, please look up the difference between “historic” and “historical.” Now there is an example of widespread “erroneous” usage!

    • It helps to understand the Zybach brand of scholarly rigor to know that your PhD about fire in the Oregon Coast Range makes you an expert in very dissimilar dry forest types – so much so in fact that you don’t even need to read any new science unless you are paid to do so. I’ll be sure and keep that in mind when reading all your comments.

      • 2nd Law:

        Always good to keep someone’s expertise and limitations in mind when communicating with them. One reason I generally dislike having public discussions with anonymous people. However, I read the Abstract and that was enough to know that I wasn’t interested in reading the remainder. My statement about fire regimes was reason enough. There’s a mass of literature out there and I (and anyone else) can’t read it all — nor do I even want to. For example, I strongly disagree with the binary “wet” and “dry” forest concept to begin with — I greatly prefer dealing with forest types and sub-types — and adding any kind of (probably non-human) “fire regime” to the mix makes it even more unpalatable to me. That’s why Gore invented Abstracts in the first place, and why a single raw oyster is usually enough for most people to know whether they like oysters or not and whether they should order a full platter of them. Or not. Part of rigor is to be discriminating about what you read and how you spend your time. Reading this kind of stuff isn’t worth my time — unless I’m being paid to review it.

    • Thanks, Guy:

      Grammar Girl sounds like a lovely and very helpful person! I was going off the phrase: “erroneous notions about historic forest conditions and fire regimes.” First, I remain doubtful about most of what I read about non-human based “fire regimes,” and second, there is nothing “historic” about them or about most forest conditions that I know of. Common error, but as a person dealing constantly with historical documentation and historic periods, events and people, I’m a little sensitive to the widespread misuse of these terms. Some might say “over-sensitive.”

      PS I did notice that Grammar Girl, in her otherwise excellent definition, did make a grammatical error herself (I am not this picayunish in real life, honest) when she wrote: “A “historical occasion” would be just some occasion in the past” — this should have correctly been “An” historical occasion, unless the rules have changed in the 50+ years since this was first taught to me.

  3. Bob and Larry

    Agree with you both

    Yes, Bob, “An” is still being taught as being appropriate when the following word begins with a consonant. “A” is appropriate when the following word begins with a vowel. The only reason that I know that is because I’m doing some volunteer after school tutoring. It’s doing quite a bit of good to keep me honest.

    Matthew

    As I stated in the last arrow of this link: http://forestpolicypub.com/2014/02/03/wild-buck-timber-sale-undercuts-forest-restoration/comment-page-1/#comment-37802
    We live in the present not the past. We can not recreate the weather nor the temperatures of the past so we can not recreate the environment of the past so since the forests of the past were dependent on the the past environment, we can not restore forests to the past. Global change has always existed and any attempt to freeze it to one point in time is pure silliness. Time marches on relentlessly.

  4. Morning Gil,

    As I stated to your comment over at “Wild Buck”….

    I’ve never once said anything about returning forests to some prehistoric conditions, or a specific point in the past. And, honestly, I know of nobody in the forest protection movement who feels this way. What we’ve repeatedly said (through the Restoration Principles and other places) is that restoration involves removing impediments to naturally functioning ecosystems. Thanks.

  5. Matthew, we’ve had this conversation many times about the framing of the wildfire issue by some scientists. Earthquakes and floods are natural too, not to speak of cancer and broken bones, but we do try to manage the impacts to human populations and other things we care about.

    We could also go to “what used to be” is not “what will be” in the future due to climate change so why is “what used to be” relevant?” Scientists can shout it from the rooftops and they can publish in Nature and Science; they can claim it’s relevant to current policy, but it’s not. Well, Bob would be more nuanced about this perhaps..

      • I haven’t really been fighting the war on wildfire. It is the war on drought that I had been conscripted into. That is really when overstocking, bark beetles and wildfires come into play the most. Here in the Sierra Nevada, we have already seen the results of “letting nature takes its course”, in Yosemite, especially. We should not be preserving prime bark beetle habitats, as Chad Hanson prefers.

        • Personally, I’m conscripted to the war on wildfire and have been for several decades. I just think the way we are going about it is stupid. I think we should be fighting fire with fire, not with outdated airplanes dropping chemicals everywhere and inexperienced people setting backfires under chaotic conditions and decision-making situations. Those are losing efforts, and the evidence is everywhere. It’s a fuels problem, pure and simple, and “fire suppression” and “climate change” are just feeble excuses for failed theories and outdated approaches. In fire-prone forests, the best approach — and one proven thousands of times over thousands of years — is to set them on fire first, under controlled conditions, before catastrophe strikes. Such an approach would pay for itself many times over, create tens of thousands of well paying jobs, put millions of dollars into government coffers, improve our drinking water supplies, stabilize our wildlife habitat and the populations that depend on it, reduce air and water pollution, and so on. Suppression actions under massive fuel build-up situations are definitely cases of too little too late and have very little to do with current out-of-control conditions across the landscape. In my opinion.

            • Thanks, Andy:

              But what does Dave Iverson think? I’ve been involved in this conflict so long I can’t tell anymore if it’s a war or if I’m just beating my head against the wall. Either way, it hurts and I’m not sure it’s worth the effort. But I will manage, given the opportunity.

              • FS employees are expected to do two jobs; their regular work and fighting fires. During fire season, especially when things are really popping, FS offices around the nation empty out as everyone puts on their hard hat, grabs their laptop, and heads out to join a fire overhead team. Dave didn’t believe in the war, so he never did get a red card throughout his 30+ year FS career. As to what he actually thinks, I’ll go rattle his cage and see if he’ll let us know.

                • Let’s also not forget that, based at least on what I’ve observed here in the northern Rockies, fire season is followed very closely by 2 1/2 months of hunting season during which it seems most Forest Service employees decide to use up a week or two of vacation time, on a rotating basis, because backcountry hunting is something they enjoy and value.

                  Then hunting season if followed very closely by the holiday season, which brings about more vacation time on a rotating basis.

                  Overlay the wildfire, hunting and holiday season with the recent fact that often times the Forest Service doesn’t get much info on their budgets for the federal fiscal year (starting October 1st) until well into the new year (ie after January 1st) and you can see that for many practical purposes many Forest Service employees only have 6 months of a year to effectively and efficiently do their regular work.

                  Please don’t interpret any of this as being anti-FS employee or against employees taking their well-earned vacations. I’m simply relating a series of events we have witnessed playing out time and again here in the northern Rockies when trying to work together with the Forest Service through “collaboration” or through the NEPA process for a variety of projects. Pretty much from July until January it can be very difficult to get a ‘quorum’ or ‘critical mass’ of Forest Service employees, and the result of all this is delays in the NEPA process or implementation, etc. Fortunately, some people can just blame environmental groups for this situation and leave it at that.

    • Hello Sharon, I’m not sure your analogy about Earthquakes and floods holds true in this case, because I don’t know of anyone who’s really denying the existence of Earthquakes and floods, like some people seem to be denying the fact that historically there were mixed severity fire regimes in Ponderosa pine and mixed-confir forests.

        • Once again…..

          Abstract, p. 1

          “There is widespread concern that fire exclusion has led to an unprecedented threat of uncharacteristically severe fires in ponderosa pine and mixed-conifer forests of western North America. These extensive montane forests are considered to be adapted to a low/moderate-severity fire regime that maintained stands of relatively old trees. However, there is increasing recognition from landscape-scale assessments that, prior to any significant effects of fire exclusion, fires and forest structure were more variable in these forests….We compiled landscape-scale evidence of historical fire severity patterns in the ponderosa pine and mixed-conifer forests from published literature sources and stand ages available from the Forest Inventory and Analysis program in the USA. The consensus from this evidence is that the traditional reference conditions of low-severity fire regimes are inaccurate for most forests of western North America….Our findings suggest that ecological management goals that incorporate successional diversity created by fire may support characteristic biodiversity, whereas current attempts to ‘restore’ forests to open, low-severity fire conditions may not align with historical reference conditions in most ponderosa pine and mixed-conifer forests of western North America.”

          Conclusion: p. 12

          Our findings suggest a need to recognize mixed-severity fire regimes as the predominant fire regime for most of the ponderosa pine and mixed-conifer forests of western North America….For management, perhaps the most profound implication of this study is that the need for forest ‘restoration’ designed to reduce variation in fire behavior may be much less extensive than implied by many current forest management plans or promoted by recent legislation. Incorporating mixed-severity fire into management goals, and adapting human communities to fire by focusing fire risk reduction activities adjacent to homes, may help maintain characteristic biodiversity, expand opportunities to manage fire for ecological benefits, reduce management costs, and protect human communities.

          • I. for one, do not choose to ignore human interests, including protecting wildlife, water quality and other forest amenities severely affected by enhanced wildfires, enhanced bark beetle populations and “whatever happens”. Also, there seems to be no lack of mixed-severity wildfires in our forests. There is no need to have more of such wildfires, and old growth stands are most at-risk to “whatever happens”.

            Current human populations don’t want high-intensity wildfires, especially when they impact people, as they always do. They do not care about “preserving” and “restoring” levels of “bad things for humans” to historical “norms”. Yes, people do not like it when wildfire drift smoke from hundreds of miles away keeps them from living their lives the way they want.

      • Yes, people who are interested in historic vegetation ecology can discuss what it used to be from now until forever. Even if some people think differently about the pst, it doesn’t alter my point of view. Which is:

        1. Fuels treatments are needed to provide defensible space for roads, infrastructure and communities.

        2. If you want to change vegetation for other reasons “restoring the past” is not a good argument to me. “Making forests more resilient to fire” or “developing landscape scale SPLATs (or whatever they are)” to me are good arguments.

  6. I’ve been working in mixed fire severity forests with a Ponderosa Pine component for the past 30 years. I do believe here in West Central Idaho, that were more stand replacing fires that occurred than the current meme of frequent non-lethal underburns. The even aged stands are proof. But there are many factors that influence that, including aspect, north and east aspects typically are moister sites with deeper soils and heavier stocking, these didn’t burn as often, and when they did they were often mostly lethal at the stand level. Ground slope also plays a factor, as fire tends run up steeper slopes. These fires may have been stand replacing, but did not wipe out every tree in the vast acreages that we are seeing from our mega-fires we’ve been experiencing lately. I often see scattered clumps or individual old large ponderosa pine, western Larch, and Douglas fir. They were the seed source for the even aged stands that they are found in.
    These types of stands with are often more suitable for regeneration using seed tree, shelterwood, or reserve tree type prescriptions rather than thinning. But thinning seems to be politically correct, and regeneration not so, since it is associated with the clear cuts of the past .

    • Michael:

      In the forested areas I have studied, even-aged stands have two basic origins: established following a stand-replacement event, and established via the seeding of former grasslands and shrublands. The latter phenomenon often correlations to sharp reductions in human populations caused by widespread diseases and have typically occurred during the past 500 years as European and African diseases were first introduced into North America. They are evidenced by the absence of trees and/or snags older than 500 years in the stands, or of identifiable prisms in soils or lake sediments older than 500 years.

      And yes, there are large variations in subsequent patterns depending on slope, elevations, aspect, and forest type and sub-type. Also to distance from seasonal and “permanent” population centers. I am curious as to why there has been little acknowledgement of John Leiberg’s work by the dry forest/wet forest fire regime folks in these regards. I am also curious as to how the documented fire histories of SW Oregon, for example, compare to the forests you are familiar with in west-central Idaho. And I believe he may have also done some work in your area. I’ll check my sources and put them in a regular post (that CAN be searched), and also look for some references to his other reports. I’d be very interested in your comments on these.

      A while back I posted some quotes from Leiberg’s 1899 report in that regard, but can’t get WordPress to search the posted comments or to display more than 18 of my most recent comments.

      • Another item that can be overlooked for creating an even age stand structure or an even aged understory stand component is the overgrazing that occurred in the late19th century, and early 20th. Grazing was basically unregulated, and in places the native grasses were removed under the parklike stands. The livestock stirred up the soil and provided a seed beds for conifers and brush species. Lack of grasses reduced the chances for low intensity ground fires.

      • Bob, I figured it out for people who have access to Dashboard. Go to dashboard, go to comments, type your email into the search block there. I got 123 of my comments. It is rare that anyone else will type your email into a comment but it shows for each of yours, so it seems to work as a search tool at least in that search box.

  7. Pingback: Wildfire: Study questions U.S. policy of forest ‘restoration’ | A New Century of Forest Planning

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