Fire scientists continue debate in the comments section

Last week this blog featured a couple of recent news articles with fire scientists discussing their latest research and understanding of the role severe fire plays in some western landsacpes.  One of those articles I highlighted was Emily Guerin’s piece over at High Country NewsFire scientists fight over what Western forests should look like.”

As interesting as Guerin’s original article was, perhaps even just as interesting has been the discussion taking place in the comments section to the article – a discussion that includes some of the leading fire scientists themselves.  Below are some excerpts from the on-line comments section, but the entire comments section is certainly worth a read:

Richard Hutto
Sep 19, 2012 09:02 AM

Swetnam and Brown “…questioned how ponderosa pines could regenerate if Baker and Williams are correct about severe fires having scarred Western landscapes for generations.” They regenerate the same way most wingless pine seeds do–by animal dispersal. I have numerous photos of Clark’s nutcrackers and Mexican jays extracting seeds from cones on severely burned ponderosa pines (see photo evidence on our facebook page here: The more you learn about severe-fire ecology, the more it all makes sense–plant, beetle, and bird adaptations that are apparent even in many of our dry mixed-conifer forest types!


Chad Hanson
Sep 22, 2012 12:54 PM

In the artice Malcolm North incorrectly states that the General Land Office data used by Williams and Baker is a “very scant data set” that does not allow for extrapolation to the landscape scale. In fact, this GLO data comprises thousands of sites over entire landscapes. The data used by Williams and Baker, in fact, is by far the largest data set ever used to address the historic occurrence of high-severity fire in ponderosa pine and mixed-conifer forests. As for the comments by Swetnam and Brown, who imply that ponderosa pine and mixed-conifer forest does not naturally regenerate after high-severity fire, this assumption is contradicted by the scientific literature. Savage and Mast (2005) (Table 3) found hundreds of stems per hectare of natural regeneration following high-severity fire in Southwest ponderosa pine forest. Haire and McGarigal (2008) and Haire and McGarigal (2010) had similar findings, indicating substantial natural regeneration of ponderosa pine and other tree species even in large high-severity fire patches, especially within about 200 meters from the edge of high-severity fire patches (which accounts for most of the area experiencing high-severity fire), and lower but still significant levels (for the purposes of establishing new forest stands) even farther than 200 meters into high-severity fire patches. Similar results have been reported outside of the Southwest in mixed-conifer and ponderosa pine forests (Donato et al. 2006, Shatford et al. 2007, Donato et al. 2009, Collins et al. 2011 [Plumas Lassen Study 2010 Annual Report]). There are likely numerous mechanisms for this, including seed survival (which may occur more often that some assume), dispersal by animals, and dispersal by wind.


Peter Brown
Sep 25, 2012 02:34 PM

Hey, all I know is what the photo above shows: recent high severity fires in Front Range ponderosa pine forests are not coming back as dense even-aged stands of trees. Far from it, in fact. That photo was taken this past June, almost 10 yrs to the day after Hayman took out about 50,000 acres of forest with nary a living tree left. You could search for days for a seedling that was not planted by either FS and Denver Water (they’ve planted a few 1000s of acres, but still a lot of treeless landscape out there). Maybe those corvids are busy as bees somewhere, but they’re not having much luck with re-establishing those 50,000 acres very fast. And it’s not just Hayman; wander around in any recent fires in the Front Range and see how treeless those areas still are.

And this is in the exact same area we reconstructed fire history before the fire (published in 1999) that was the first fire history in a ponderosa ecosystem that provided concrete evidence of crown fire. But the crown fire patches we reconstructed were acres to 10s of acres in size, not the 1000s to 10000s of acres we’re seeing today.

And hence the crux of the question: what was the scale of crown fire relative to surface fire in the historical forest, and how has that changed today? No one disputes that *passive* crown fires occurred (where fire spread across the landscape was primarily through surface fuels, but occasional trees or patches or trees would crown), whereas current fires are dominated by *active* crown fires (with fire spread mainly through aerial fuels). One other point about the uncharacteristic nature of recent fires, at least Hayman: 400-600 yr old trees we sampled in our 1999 study that had recorded multiple fire scars (i.e., had experienced 6, 8, 10, 15 *surface fires* in their lifetimes) all died during Hayman. Hanson, I have to laugh every time I see your report on “the myth of catastrophic fire” [link here, added by MK] because in the cover photograph there is what looks to be a dead tree that takes up the entire left side of the photo, with what sure looks to be a catface with maybe 8-10 fire scars recorded in it. An incredibly unintended ironic comment on your entire thesis in that paper. Here’s a tree that experienced 8-10 surface fires in its lifetime, and then dies in a recent high-severity fire.


Richard Hutto
Sep 25, 2012 02:54 PM

The picture above is indeed instructive; it shows that there are no big ponderosa pines! Why? They were all harvested before or after the severe fire event…might that have something to do with the fact that there is little recruitment? The more unnatural treatment a forest gets, the more unnatural the result.

The fact that charcoal trees have fire-scars is also instructive. Of course fire-scarred trees eventually burn down…that’s the point! If they didn’t burn down every 300 years or so, on average, they’d live 4,000-5,000 years, just as the other tree species that REALLY have a history of avoiding severe fire do. A little more perspective from evolutionary ecology might help here.

Again, nobody is arguing that some dry PIPO forests are in an unnatural state, and getting unnatural results from recent fires…the BIG point is that the story applies to a small proportion of western forests, and to almost none of the mixed-conifer forest types.


  1. While this is a mildly interesting discussion, it seems rather academic today. We don’t need to completely understand the past to do things today if we believe, which I do, that climate change is unprecedented in recent times. When pushed some people will vaguely say “the past should inform the future”. Perhaps we really need to dig in to when it does and when it doesn’t.

    Here is the next comment after the Richard Hutto sept 24 2:54 by Peter Brown, which I think is very important because Peter knows more about the Hayman.

    In many many locations there were mature, dense stands of ponderosa pine before Hayman. Especially around Cheesman Reservoir there hadn’t been any harvesting since the dam went in in the early 20th century. No, there is no recruitment because there is no seed source; ponderosa has relatively big seeds that do not go far from a parent tree. Perhaps a little perspective from silvics might help here as well.

    And again, the question is one of scale: the oldest known ponderosa pine is 925 years old. Rarely do they get over 500 to 600. Individual trees die from all sorts of reasons, and often large patches die all at the same time for various reasons as well. We sample snags or logs all the time, many of which have evidence of blue stain (i.e., they died of bark beetles). We have plenty of evidence of trees died of drought. And even windthrow. And… even fire. But there is absolutely no hard evidence at all that the *scale* of recent crown fire “patches” is not completely unprecedented over the past several hundred years to perhaps millennia in most areas where ponderosa pine today dominates. And that is a huge area of western forests, and by goodness, a lot of the mixed-conifer forests as well.

    Hutto seems like a qualified scientist, but I wonder why he would make make assertions about logging in an area that he is unfamiliar with? There were trees producing cones in the area, now there are not. Is he claiming that if they were bigger they would have survived the Hayman fire? There isn’t that much soil there so they just aren’t going to get very big.

    Hutto also says “The more “unnatural treatment” a forest gets the more “unnatural result” “doesn’t sound like a scientific statement to me. It sounds like what Bob Lackey would call “normative science.”

    Perhaps today everything is now unnatural due to climate change, so then according to Hutto we will have be unnatural regardless of what we do or don’t do. So why is “naturalness” such a focus of the above dialogue, if it’s impossible to achieve?

    • Hmmm…I wonder how “many many locations” is defined, scientifically. Would that be “normative science” there Sharon?

      And wow, who knew that Colorado was so flush with mature stands of ponderosa pine prior to the Hayman fire (which was started by Terry Barton, a forestry technician with the U.S. Forest Service).

    • And he’s Dr. William Baker’s response to Peter’s comment….

      William L Baker
      Sep 26, 2012 12:33 PM

      Peter says “But there is absolutely no hard evidence at all that the *scale* of recent crown fire “patches” is not completely unprecedented over the past several hundred years to perhaps millennia in most areas where ponderosa pine today dominates. And that is a huge area of western forests, and by goodness, a lot of the mixed-conifer forests as well.”

      There is just this evidence, in a new paper in the scientific journal, Ecosystems:

      Ponderosa pine regenerated just fine in many cases after high-severity fire in the past, which we know because places that were recorded as high-severity fires in the late-1800s to early 1900s now are well forested. Research is underway in the Front Range to try to understand the present lags in regeneration, to see whether this related to increasing drought or other factors, but 10-year historical lags in regeneration are documented.

      • What about “higher” severity fires, beyond those anecdotal historical accounts? It is very clear that today’s abnormally dense and flammable stands that burn cause more soils damages than those historical fires ever did. Also, where Indians burned, fuels were permanently reduced, for thousands of years. In fact, we are still reaping the benefits of their expert burning..

        • Larry: I’m not sure it’s “very clear” or that “abnormally dense and flammable” define our forests. Or that these fires “cause more soils [sic] damages than those historical fires ever did.”

          I also find it interesting that you claim “where Indians burned, fuels were permanently reduced for thousands of years.”

          Yet apparently this type of burning, which you claim reduced fuels for 10 whole centuries caused zero soil damage? Really?

          • There are many varieties of soils in our forests, and many kinds of damages, so “soils damages” is both scientifically and grammatically correct, Mr. English Major.

            In many parts of the west, Indians were experts at applying fire to their landscapes, at the appropriate times of year, with proper fuel moistures. I keep a sugar pine cone suspended in the manzanita in my yard. When fuel moisture is high, the cone is closed. When it is dry, it is fully opened. It would be very easy for humans to burn off the bear clover and brush every few years, with minimal damage to soils. Their fires burned fast and cool, with the pungent bear clover providing flashy fuels. Fire-adapted pines thrived under these conditions.

            Here in the Sierra Nevada, it is scientific fact that today’s forests are substantially thicker, with a radical change in species compositions. Some people are choosing to preserve this “unnatural” condition. These same people also believe that these forests will receive less precipitation in the coming years and decades.

            So, are we to expert “nature” to thin out these forests, or expect drought, bark beetles and wildfires to “thin out” our forests?

      • Matthew, it seems like this topic skips between the generic and the specific, which makes it confusing and hard to follow.Some of my colleagues have pointed out a couple of inaccuracies.

        First, ponderosa seed is mostly wind blown and falls generally close to the trees as it says in the silvics manual here.

        “Ponderosa pine seeds are not disseminated naturally over extensive distances. In central Oregon, seedfall at 37 m (120 ft) was only 22 percent of the seedfall at the west edge of a cleared area, and at 120 m (396 ft) it was only 8 percent (3). ” The quote above kind of implied pine seeds don’t have wings..but of course they do..

        Here’s a photo.. (note I spend many of my younger years observing ponderosa pine seed years, climbing ponderosa trees for cones, and visiting extractories extracting seed.)

        The decline of seed density with distance is also true of other species that Jerry Franklin and others also studied (I think various true firs and Doug-fir)… the number of seeds drops off with distance. It’s just physics, the same thing happens with pollen. There is still some at a long distance away, but not a lot.

        Second, not to wax all biblical, but the seed has to fall on the right soil.. bare mineral soil, and germinate at the right time of the year so there is enough moisture, and not be overtaken by shrubs, forbs, or grass (this might be called the California problem). It is true that squirrels cache cones but they tend to be in a clump (the cache) and not spread out over the landscape.

        Third, I think that there is some protection of seeds if the seeds are in soil that hasn’t burned up. Seeds may tend to accumulate in the duff, which may or may not burn. Also little seedlings can be protected, and many fires have places that just don’t burn hard enough to kill trees or seedlings or seed.

        If Clark’s jays or nutcrackers are extracting seed from burned cones, aren’t they eating the seed? And even if some seeds fall out of their beaks, it seems like that might not be enough to start a forest in a given spot, given the pondo proliferation problems of getting started and not get overtopped outlined above.

        In a good year, in a pine stand the Silvics Manual says “, In a good seed year as many as 852,050 seeds per hectare (345,080/acre) may reach the ground (19).”

        And if you’ve been in some pine stands in the west, you’ll know that a good seed year can still have low regeneration due to needing “good ground” open at the same time there’s one of P pines intermittent seed years.

        So all that is generic information.

        Given all that, you can look at parts of the Hayman and see nada, zero, zilcho of ponderosa babies. Is that because of the intensity of the fire? Is that because the soil is so minimal in places and what was there washed away (removing seed and seedlings)?

        I don’t know why. But I am also losing track of how these generalities and specifics are related to anything in the above discussion. We can observe the Hayman and see how things are, and wonder about how we should prefer them to be.

        I still don’t see how arguing about how things were, really changes anything we currently see or want to do.

        • Sharon, I really do find the P-pine seed info interesting. However, Dr. Richard Hutto has photo evidence of Clark’s nutcrackers and Mexican jays extracting seeds from cones on severely burned ponderosa pines (see photo evidence on the UM Avian Science Center facebook page here:

          Clark’s nutcrackers and Mexican jays aren’t exactly small birds, so one could assume they do a pretty good job of spreading P-pine seeds far and wide. At least much further and wider than the seeds simply falling form the tree. Yes, I’m sure that the birds do intend to eat the seeds they extract; however, I’m also sure that the birds don’t achieve this task with 100% success all the time. Just like I’m sure other birds, or squirrels, etc are not 100% successful all the time at eating the seeds they collect. All it takes to grow one P-pine is one seed. And I believe in nature this type of activity (ie animals spreading seeds) is happening all day, every day…all year, every year.

          • The interesting things about the HCN article is that we are talking about a real place with real observations and people keep talking about generalities.

            As to the Clark’s Nutcracker,

            Here’s what it says in Wikepedia (could be wrong)

            The most important food resources for this species are the seeds of Pines (Pinus sp.), principally the two cold-climate (high altitude) species of white pine (Pinus subgenus Strobus) with large seeds P. albicaulis and P. flexilis, but also using other high-altitude species like P. balfouriana, P. longaeva and P. monticola. During migrations to lower altitudes, it also extensively uses the seeds of pinyon pines. The isolated Cerro Potosí population is strongly associated with the local endemic Potosi Pinyon Pinus culminicola. All Clark’s Nutcrackers have a sublingual pouch capable of holding around 50-150 seeds, depending on the size of the seeds;[2] the pouch greatly enhances the birds’ ability to transport and store seeds.

            “Clark’s Nutcrackers store seeds, usually in the ground for later consumption, in caches of 1-15 seeds (average of 3-4 seeds).[2] Depending on the cone crop as well as the tree species, a single Clark’s Nutcracker can cache as many as 98,000 seeds per season.[3] The birds regularly store more than they actually need as an insurance against seed theft by other animals (squirrels, etc.), as well as low availability of alternative foods; this surplus seed is left in the cache, and may be able to germinate and grow into new trees, if the conditions are right. Through this activity of caching and over-storing, the bird is perpetuating its own habitat. Closely tied in with this storage behavior is the bird’s remarkable long-term spatial memory; they are able to relocate caches of seeds with remarkable accuracy, even nine months later,[4] and even when the cache sites are buried under up to a meter (3 ft) of snow.”

            If 1)they don’t prefer ponderosa
            2) they mostly find what they cache

            what are the chances that there are enough caches out there to successfully reforest the Hayman (which was many contiguous acres of PP).

            You would have to assume:
            They were hanging around ponderosa when they prefer white pines,
            They cached a lot of seed and didn’t find it
            Nothing else (ground squirrels or insects or ?? ate it)
            It hasn’t come up yet, but it will in the future,
            When it comes up, nothing will have been established there yet so those seedlings will successfully grow.

            “Scientists” have heretofore thought that winged seeds generally dispersed by wind, and those with vestigial wings or no wings by birds or other animals, as in Ron Lanner’s book.

            Like politics, all biology/ecology is local.

            • Sharon, seriously, what’s with your “specific” vs “generalities” mime? Are William Baker, Chad Hanson, Richard Hutto, Mark Williams et al only speaking (and conducting their research) in generalities and not specifics?

              • No my point was that the Hayman is a specific place with specific conditions, and the things empirically observed there can’t be realistically argued about by generalities derived from other places.

                I have experienced, directly, working with ponderosa pine regeneration on the Eldorado, all over Central Oregon, and just observationally in Colorado. I’ve attempted to use growth and yield models derived in Idaho (I think) to predict growth in central Oregon (didn’t work well). I wandered the woods looking for trees to select and noted the variety of ecoclasses that ponderosa grows in.

                I’ve looked at thinning piles in the Black Hills and been amazed at the size and amount of material compared to other ponderosa pine places I’ve worked.

                I guess I have an appreciation for the different conditions that ponderosa lives in and would be hesistant to generalize or assume that my knowledge of one area would apply to another.

  2. Here’s another thought-provoking comment just posted at HCN:

    Bill Gore
    Sep 26, 2012 08:36 AM

    So much energy, money and time spent trying to ‘manage’ the landscape. So many of us here seem to be either academics or landscape managers of some sort. And yet, despite legions of career foresters, numberless publications, billions in various government subsidies we remain clueless and helpless in the face of the surprises thrown at us. The west will simply just not settle down and be Connecticut or Luxembourg, and we culturally cannot handle this. We are total control freaks, armed with some very flimsy science, and we are culturally freaking out in the face of a landscape that is still wild, that will never be wrapped in chains like Connecticut. Everyone’s a control freak: they demand climate, vegetation, fire regime, precipitation be just so to serve their agenda. Give it up! It is a privilege to live here. If you choose to pour everything into a moneypit subdivision surrounded by megatons of incendiary fuels, then you are the bigger fool, and you do not deserve the lives of our best young people working their asses off in choking smoke to save your ‘investment’. The early explorers, Fremont et. al., were purely mercenary, like Louis and Clark, simply scouting and surveying for distant corporations (the feds). Their snapshots were just that-casual descriptions of conditions. Now we are obsessed with returning to baseline orthodox environmental purity-where is that? Early, middle or late Pleistocene? 1850 or 1950??

  3. “… it shows that there are no big ponderosa pines! Why? They were all harvested before or after the severe fire event” Yep, if the observations don’t match the mindset, you can always blame the past. Yep, it’s all those dead evil forest rapers, who have been replaced by brand new live evil forest rapers, who deserve the blame. well, here in the Sierra Nevada, there are still plenty of huge old pines, that will surely die when the forest, now dominated by ultra-flammable true fir and cedar. burns to a crisp.

    It seems that some people are wanting to preserve currently unnatural stands, ignoring the impacts and potential bad outcomes. In fact, they WANT you to think that there are NO bad outcomes, ever.

  4. Just to be fair in reporting my extensive observations in post-fire landscapes, I have seen evidence that dense stands can, and do develop, in low to mid severity burns. If the fire occurs during a decent cone year, most of the seeds do find bare mineral soil, perfect for germination. You often see a “carpet” of tiny saplings, growing underneath the fire’s survivors.

    Working in the old Pilliken Burn, on the Eldorado NF, I found it interesting that it was the white fir that dominated in regeneration, due to a bad cone year for pines, that year. It resulted in a pure white fir stand, where jeffrey pines should have dominated. The “carpet” of white fir even bypassed the local brush species. I have to think that this situation wouldn’t be that uncommon.

  5. When I see posts with lots of comment’s I can almost guarantee that shortly after I start reading them I will say to myself, “there would be a lot less argument/misunderstanding and a lot more clarity if folks would use the phone or skype instead.” There is so much opportunity for translation error via this method of communication. No wonder folks stay entrenched in their own perspectives.

  6. Craig, that’s true in a way, but some would grant a special dispensation to “scientists’ opinions”. I think it’s an important public service for some scientists to discuss their findings in public so that 1) people are aware of the kinds of discussions they have and understand better how the scientific process works
    and 2) so that those younger who are interested in these discussions and are curious about the different perspectives can think about a career in science.

    I remember once when I was administering the McIntire-Stennis program (of course “research administration” is a bit of an oxymoron, but that’s another story). I visited School X. At the time, School X had two excellent professors A and B, who were both forest ecologists but had very different ideas about how forests should be managed. They are both excellent and I have enormous respect for both of them, but they don’t always see eye to eye.

    On my visit, I mentioned to one of their students, “it would be great to be at school here for the discussions between professors A and B and their students – you must learn so much!”

    The student replied something along the lines that A and students of A on one hand, and B and students of B on the other hand, mostly stuck to themselves. In fact, it was implied that there was a bit of tension.

    Anyway, because opinions of university faculty are sometimes lumped and called “science”, I think the discussion of “facts found and conclusions drawn” is important to be done in public, at least sometimes. And the philosophical issue of “when to be “natural” and not” is of great importance as it is an underpinning that determines the relevance of this particular debate over fire history to actual management questions.

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