Guest Post: When to let a dead tree lie

The following piece was written by Brandon Keim, who provides comments on this blog once in a while. It’s shared here with his permission. – mk

When to let a dead tree lie

It’s often argued that logging trees killed by insects or diseases is beneficial for forests—but evidence is mounting that it causes long-term ecological disruption.

By Brandon Keim

When trees are damaged by insects or disease, there’s often pressure to cut them down. It’s argued that “salvaging” these trees is actually beneficial for forests—but evidence is mounting that it causes long-term ecological disruption.

The latest findings come from Białowieża Forest, a 550-square-mile woodland that straddles Poland and Belarus and is a last redoubt of the vast forest that once stretched from France to Russia. Long the protected domain of aristocracy, Białowieża escaped large-scale logging; it’s one of the few places in Europe where natural cycles of wind, fire, and disease still shape a forest at landscape scales.

Only during the last century has logging taken place. A prime target is the dead trees that are present in far larger numbers than in commercially-managed forests, in particular trees afflicted by bark beetles. Salvage logging following outbreaks is presented by supporters as ecologically beneficial, but it “alters the potential for natural regeneration,” says Anna Orczewska, an ecologist at the University of Silesia.

Orczewska is the lead author on a new study, published in the journal Biodiversity and Conservation, of what grows in the aftermath of salvage logging in Białowieża. The forest is set on a new trajectory; “the human ‘clean-up’ attitude,” writes Orczewska and colleagues, “inevitably leads to the homogenization of the forest.”

The researchers looked at the so-called herb layer—low-growing grasses, ferns, and flowering plants—in sites where spruce and pine trees were killed by beetle outbreaks and either logged or left alone. Salvage logging in Białowieża, as in many places worldwide, involves clearcuts followed by removal of trees with heavy machinery and plantation-style replanting.

Several years later, the herb layer in logged sites was dominated by disturbance specialists rarely found within the intact forest. The previous herb layer was largely destroyed by machinery or withered in the suddenly intense sunshine. Their seeds did not sprout. When beetle-killed trees were left alone, though, the original herb layer regrew. Dead trees provided necessary shade; their fallen trunks and branches created pockets of protection from grazing.

In short, the regrowth that occurred after natural disturbance was dramatically different from that which occurred after human-driven disturbance. And whereas the former represent the first stages in a cycle that will eventually restore the original plant community, the latter represent something different. The new, disturbance-specialized assemblage may persist for decades. “In some cases, it seems that pre-disturbance herb layer assemblages never recover,” write Orczewska’s team.

They argue that salvage logging is actually worse than disease outbreaks for Białowieża’s plant communities—a lesson that, though based in this study on the research in Białowieża, is broadly applicable elsewhere. Natural disturbances create structurally and biologically complex forests.

“In the era of global warming we should eliminate salvage logging, at least in forests which still hold the potential for natural regeneration,” Orczewska says. “Instead we continue cutting.”

Source: Orczewska et al. “The impact of salvage logging on herb layer species composition and plant community recovery in Białowieża Forest.” Biodiversity and Conservation, 2019. Open access here.

About the author: Brandon Keim is a freelance journalist specializing in animals, nature and science. He is now writing Meet the Neighbors, a book about what animal personhood means for our relationships to animals and to nature. Connect with him on Twitter, Instagram and Facebook.

25 thoughts on “Guest Post: When to let a dead tree lie”

  1. Surprise, surprise… leave ecosystems alone in order to allow it to do its own healing as it all has evolved over eons…

    Versus

    “Management”: Ruling by Raze and Run mentalities, then claim credit under the ruse of “stewardship and restoration”?

    Uh,huh… (oh, and then deny the sudden catastrophic aftermath of Anthropogenic alterations of earth ecosystems and claim causation by “natural processes.”)

    Hubris is a terminal disease.

    Reply
    • “Hubris is a terminal disease.” Yes, and it afflicts some in the environmental community as well as the pro-active management crowd.

      Reply
      • I agree Steve.
        Except, salaried collaborationists posing as environmentalists while compromising with salaried (mis)”managers” of public forests involve the original meaning of hubris as Wiki notes,

        “In ancient Greek, hubris referred to “outrage“: actions that violated natural order, or which shamed and humiliated the victim, sometimes for the pleasure or gratification of the abuser…”

        Reply
  2. I wonder if the idea of “salvage logging” means different things to different people in different conditions in different countries.

    “In the era of global warming we should eliminate salvage logging, at least in forests which still hold the potential for natural regeneration,” Orczewska says. “Instead we continue cutting.”

    If we go back to basic regeneration concepts some tree species do better in certain conditions in shade, and others in the open. Leaving jackstrawed dead trees (say LPP) can be an invitation for regeneration-toasting fires- I’ve seen it happen with no seed sources post second fire. We also have to consider what value we place on tree regeneration as opposed to graminoids, herbs, etc. – a human value.

    In short, the regrowth that occurred after natural disturbance was dramatically different from that which occurred after human-driven disturbance. And whereas the former represent the first stages in a cycle that will eventually restore the original plant community, the latter represent something different. The new, disturbance-specialized assemblage may persist for decades. “In some cases, it seems that pre-disturbance herb layer assemblages never recover,” write Orczewska’s team.”

    So this uses the concept of “return to previous” (not value-laden) with “recover” which does. Yet some project that main forest species will move and other changes occur due to climate change. So are these folks advocating not salvaging in the hope that under warming, conditions will return to what they were in the past?

    It seems to me that that argument is hugging a bit of a climate change conceptual ridgetop. Managing against climate change, the best is to leave things alone. Yet, climate models tell us if we leave them alone, they still won’t be the same. So there is some kind of perhaps inherent argument that leaving them alone makes them more resilient? But different folks have different points of view on that specific hypothesis, which we can discuss.

    Non-scientists – note how people measure “things” in the real world, but then put those measurements within the framework of “ideas about things.”
    It’s also got the “not here” lack of comprehensiveness, which IMHO doesn’t make it very helpful for policy. OK, if not salvage, then green would be better? Why? What variables would you measure to contrast the two? Or perhaps not cutting trees at all, nor using wood products? What would be the climate and other impacts of substitutions?

    But what strikes me most is that “salvage logging” is very locality dependent. For example, here’s a paper by Rhoades et al that talks about a specific fire with specific dead lodgepole- a fire/beetle salvage combo. https://www.fs.usda.gov/treesearch/pubs/56038

    I’m sure that there are a great many more studies of specific areas, and specific species/disease/insect/ fire combos.

    Reply
    • The sort of salvage logging they’re talking about in Białowieża is clearcutting (or clearfelling, in the western European argot.)

      I’d recommend reading the paper if you want to … get down in the weeds (sorry, couldn’t resist 😉 It’s not just invoking “return to previous” in some dogmatic, reflexive way; it’s arguing that going in with heavy machinery and creating large, structurally homogeneous, sun-baked clearings sets those areas on a different trajectory and ultimate affects the integrity of the forest.

      Reply
      • Brandon, if it’s this file:///C:/Users/Owner/Downloads/Orczewska2019_Article_TheImpactOfSalvageLogging.pdf
        paper, I looked at it last summer (it was published in June). But it’s hard to tell from the quotes you gave versus this abstract (yay, open access!) :

        “Białowieża Forest is one of the closest to pristine forest ecosystems in temperate vegetation zone in European Lowland, which is still being transformed by forest management. We investigated the effects of salvage logging of spruce stands killed by bark beetle on the recovery process and the biodiversity of the herb layer in the early stages of vegetation development after felling, on the habitat of mixed deciduous, oak-lime-hornbeam forest (Tilio-Carpinetum). We tested: (i) to what extent salvage logging modifies the plant species richness and diversity compared to sites left intact; (ii) whether clear-felling leads to an increase in diversity of vascular plants; and (iii) which ecological groups of plants benefit, and which are hindered by disturbance, depending on age and size of the clear-felled site.

        Salvage harvesting executed between 2012 and 2016 led to an increase in overall plant
        diversity. However, the winners were the species of open habitats, promoted by soil disturbance, whereas the number and cover of ancient forest indicator species decreased in comparison to unlogged forests. Both trends were significantly related to the increasing size of clear-felled sites, and developed right after logging. A comparison of the species composition of the disturbed (logged and unlogged) sites with undisturbed forest with stands unaffected by infestation, treated as control plots revealed the great potential of the affected sites for spontaneous recovery towards the oak-lime-hornbeam forest community, despite 50–90 years of spruce-dominated stand cover. We conclude that continuous deterioration of the forest habitats via clearcutting of stands afected by insect outbreak, followed by tree planting, substantially reduces the chances of successful, natural regeneration towards deciduous, structurally complex and diverse forests.”

        That is much more standard scientific language. In fact, I don’t get any of the value-laden stuff from it. That’s why I’m not sure that it’s the same paper.

        Reply
        • The original blog post provided the citation, title and open access link to the paper:

          Source: Orczewska et al. “The impact of salvage logging on herb layer species composition and plant community recovery in Białowieża Forest.” Biodiversity and Conservation, 2019. Open access here.

          What’s with all the attempts to sow so much distrust of so many scientific papers and/or scientists on this blog? (Especially when a basic google search could likely produce the answer to a few basic questions?)

          P.S. The lead scientist for this study was Dr. Anna Orczewska of the Department of Ecology, Faculty of Biology and Environmental Protection, University of Silesia, Katowice, Poland. The other two scientists are identified as with Białowieża Geobotanical Station, Faculty of Biology, University of Warsaw, Białowieża, Poland.

          Reply
          • Matthew, I am not “sowing distrust”, I am simply comparing what was in the paper with the quotes, and they didn’t match. I think we need to be careful that if we grant scientific research a special legitimacy, we should also be able to comment and review what papers say. I would also say (and I am not alone in thinking this) that when scientists aren’t clear about the difference between their data and their framing and opinions, it makes people in general trust scientists less. Honestly, I don’t think some scientists even realize that they are in that framing fishbowl, so I am not impugning their actions or views. I’m just saying that it is our responsibility as citizens to question authority of any kind, scientific or not.
            And the way I was trained, questioning was thought to be good for the scientific enterprise. Many scientists still believe this.

            Reply
          • That’s a bit confusing. Conceivably we would be interested in what she thinks based on the results in her paper, especially the way it was presented a person could easily infer that her opinion was based on information actually in the paper.

            Reply
  3. The message here is that it isn’t the actual cutting of dead trees that causes harm, but that salvaging trees “alters the potential for natural regeneration” that “inevitably leads to the homogenization of the forest.” That may be in some cases. In others, foresters can and do replant in ways that mimic natural regeneration, and sometimes this can lead to the restoration of the forest in less time than might happen naturally. In other words, intentional regeneration isn’t necessarily bad and can be very positive.

    The same goes for areas burned by wildfire, salvaged or not. If a fire burned in the Białowieża forest, no doubt the herb layer .. would be dominated by disturbance specialists rarely found within the intact forest, for a time. Some will argue that a burned area ought to be left alone (“let nature take its course”), but the choice of action or inaction depends on the landowner’s (and, to some extent, society’s) objectives.

    “In the era of global warming we should eliminate salvage logging, at least in forests which still hold the potential for natural regeneration,” Orczewska says. “Instead we continue cutting.”

    That’s one point of view. Another is that in many cases we must use active management to achieve the best mix of ecological, economic, and social outcomes.

    Reply
  4. In the Pine Ridge of northwest Nebraska, an area dominated by ponderosa pine, state and federal forestry staff often place downed trees (from a forest fire, wind, insects) in large piles and then burn the piles. What is the forest management rationale for such a practice?

    Reply
  5. I remind people that there are multiple ‘flavors’ of salvage logging in the forestry world.

    I can provide examples of lands I worked on, during my career, filled with salvage logging experience.

    In 1989, I worked on the Eldorado NF, Placerville RD. This road system was loaded with bark beetle mortality (mostly in crowded white fir). In these 30 years, I don’t see much in the way of impacts, even though millions of board feet in salvage came off this road system.
    https://www.google.com/maps/@38.6748449,-120.3718398,1147m/data=!3m1!1e3?hl=en

    In 1993, I was a Harvest Inspector (doing the work of a Sale Administrator) working on the Fremont-Winema NF, Chiloquin RD. The projects were within the Big Pine Fire. I see my skid trails are still there!
    https://www.google.com/maps/@42.5739292,-121.4768106,541m/data=!3m1!1e3?hl=en

    In 2005, I was a Sale Administrator on the Eldorado NF, Amador RD, working on the Power Fire salvage projects. Since then, this portion burned again, and seems to have survived the fire quite well. Without salvage, the re-burn would have been much more intense, with serious soil damages. Parts of the Power Fire salvage were not completed, due to an Appeals Court decision.
    https://www.google.com/maps/@38.4773256,-120.3475819,575m/data=!3m1!1e3?hl=en

    Here is a perfect example of an ongoing ‘experiment’, within Giant Sequoia National Monument. Our options on what to do with this particular piece of ground are extremely limited. Logging is not only banned, it is also unprofitable (the wood is worthless to loggers and lumber mills). I’m sure we’ll see what happens when it, inevitably, burns.
    https://www.google.com/maps/@35.8808392,-118.5564161,149m/data=!3m1!1e3?hl=en

    Reply
  6. I don’t understand how the authors get to the conclusions they draw. In figure 4 there is no difference between species diversity in logged and unlogged sites for the number of ancient forest species found. In figure 5 it shows that there is no difference in the cover of ancient species with the size of sites logged. It has been a long time since I have taken statistics but my understanding is that when error bars overlap you can’t prove statistical significance. An image grab of the figures I reference can be found here: https://imgur.com/a/lnmaUZ8

    Reply
  7. This exact discussion should be in every NEPA document prepared for a Forest Service salvage project. What are the effects of an action alternative compared to no-action? (And if there is scientific controversy about the effects, the NEPA document should be an EIS.)

    Reply
    • Even if the project involves hazard trees along a road? And if there is “scientific controversy”.. if you get enough scientists together, a person (lawyer) could argue that there is scientific controversy around anything.

      Reply
        • Luckily, here in California, even the Ninth Circuit Court has been deciding that the “controversy” has been settled, in salvage logging cases. It seems like the ‘new science’ is merely “agenda-driven” and inapplicable under rules, laws and policies. AND, there is still no proof that the Forest Service is clearcutting in salvage projects. (Remember, snags can be ‘saved’, either individually, or in clumps.)

          Additionally, I’d like to see entire wildfire acreages included into study areas, so that ALL the burned trees can be used in analysis, and counted as part of mitigation efforts.

          Reply
        • Hmm. a judge deciding how much of a scientific controversy there is.. how often do scientists decide how much of a legal controversy there is? Just following the lines of power here..

          Reply
          • A judge’s line of power goes back to the Constitution. They get to address the legal meaning of the NEPA term “significant.” One of the factors of significance is scientific controversy about effects. I think if the scientists took a position on how controversial something is that would count for a lot, but sometimes agencies don’t like to present the science in a way that would admit there is a controversy.

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  8. I have noticed that the forests west of the cascades, in Southwestern Oregon, will regenerate naturally with a full array of weeds, brush, native and otherwise, and a mixture of hardwood and conifers. Even old growth forests if not dominated by ferns with be full of all matter of weeds and understory brush.
    I have not noticed a great difference between salvaged areas and those not salvaged in what grows back. I do lean towards the salvaged areas being more vibrant due to the disturbance that took place during harvest.
    I think we shouldn’t forget the benefits that salvage timber can provide, not just by paying the bills, but also by the incredible products that we can create from these salvaged trees.

    Reply
  9. The hatred of rich understory native shruband, dead trees, delicate life forms that provide habitat for remarkable biodiversity runs deep in many. To them, anything that deviates from the mythological, park-like forest or open grassland is useless, ugly, dangerous. It must be removed.

    The reasons run through a usual laundry list* of misconceptions:

    1. Too much “brush” due to past fire suppression (demonizing habitat in favor of timber production and ranching).
    2. Fires are destroying California’s forests (they aren’t).
    3. Native Americans burned and thus prevented large fires (large fires have always happened).
    4. Clearing habitat will protect us from devastating wildfires (it won’t).

    *Additional information on all this can be found on our fire research page here:
    http://www.californiachaparral.org/fire.html

    Hence, we have Cal Fire, the California Board of Forestry, and Governor Newsom proposing a program to attack 20 million acres of native habitat throughout California, with huge grinding machines, logging, and herbicides. They will likely certify their program this Wednesday (12/11/19) at the Board of Forestry meeting.

    Reply
    • For me, it’s about ‘growing’ more old growth. All-aged forests have more ‘value’ to us humans (Yes, even without logging). Allowing the remaining old growth to burn and die is not acceptable to me. We need forests which survive today’s real world. I’m sure that pre-European residents of California knew that, as well.

      Reply

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