Calif. Forests: “an unnatural 300 to 500 trees an acre”

Mike Archer listed this article in today’s Wildfire News Of The Day email: “California fights wildfires aggressively—but prevention takes a back seat.”

A 19th-century California forest would have held fewer than 50 trees an acre. Today the state’s forests have grown to an unnatural 300 to 500 trees an acre, or more. That doesn’t count the 2 million drought-stressed trees a month lost to bark beetles that have killed entire stands.” [emphasis mine]

Mentions the Little Hoover Commission report, “Fire on the Mountain: Rethinking Forest Management in the Sierra Nevada.”

FYI, to subscribe to the Wildfire News Of The Day list, contact Archer at [email protected].

9 thoughts on “Calif. Forests: “an unnatural 300 to 500 trees an acre””

  1. I’m a bit offput by the “unnatural” part. Prior to their clearing, 19th-century California forests were mature. Contemporary forests are much younger. Of course they have lots more trees per acre; that’s not unnatural, it’s just a stage in succession.

    I’m not saying that’s a reason not to thin them for the purposes of managing fire, just that calling a young forest “unnatural” seems dangerously nature-blind. Unless the implication is that the species assemblage is different, and contemporary assemblages have more trees? In which case that’s still not “unnatural,” though, and the term doesn’t seem to encourage clear thinking.

    As for bark beetles … just once I’d like to see a management plan that explicitly considers the role of insectivorous birds and bugs in eating beetles, but I’m not holding my breath.

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    • EVERYWHERE you look in Sierra Nevada National Forests, you’ll see old growth. Even the youngest of clearcuts are looking less and less like a plantation, after a 25-year ban on clearcutting and old growth harvesting.

      No amount of birds can make a dent against drought-enhanced bark beetle populations. Enhancing the trees’ ‘natural’ defenses would be better, through careful “thinning from below”.

      How could we increase bird populations using forest management? Both goshawks and owls drive the management across the Sierra Nevada, already, neither of them listed.

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      • “How could we increase bird populations using forest management?”

        I can think of few ways. Reducing pesticide pollution — either from pesticides used inside the forests for insect or invasive plant control, and also originating in other areas:

        https://ca.water.usgs.gov/news/2013/PesticideAccumulationInFrogs.html

        And one could get fine-grained about where, for insectivores who migrate, they spend the rest of their time, and whether there are issues there. E.g., land use change and pollution on winter feedings in South and Central America.

        “No amount of birds can make a dent against drought-enhanced bark beetle populations….” One wonders about that. What does the literature show? Or is it one of those questions (as I suspect) that’s barely been studied at all because people don’t pay much attention to ecological interactions and ‘pest’ regulation.

        Perhaps an irruption of beetles won’t be controlled by insectivores once it starts, but it can be constrained — and the chances of future irruptions of the next worrisome insect can be reduced…..

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        • “I can think of few ways. Reducing pesticide pollution — either from pesticides used inside the forests for insect or invasive plant control, and also originating in other areas:”

          Sounds like nothing the Forest Service can do, via management. Here in California, clearcutting is banned and and pesticides aren’t used as much. Additionally, since wildfires are not reforested much, anymore, less is used there, too.

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    • Woodpecker: “As for bark beetles … just once I’d like to see a management plan that explicitly considers the role of insectivorous birds and bugs in eating beetles, but I’m not holding my breath.”
      ===

      I don’t believe there is anything that can be done to control bark beetles, even if their plan is to spray millions of gallons of science-based synthetic toxins across the landscape and even that would be a disastrous failure. It’ll have to just run it’s course.

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  2. Torgy Torgerson (Forest Service Scientist in LaGrande, OR) looked at the role of birds in controlling insects back in the 1980s and identified the important role of cavity-nesting birds when insects are at endemic (but not epidemic) levels.

    Predation by birds and ants on two forest insect pests in the Pacific Northwest…

    https://sora.unm.edu/sites/default/files/SAB_013_1988%20P14-19_Predation%20by%20Birds%20and%20Ants%20on%20Two%20Forest%20Insect%20Pests%20in%20the%20Pacific%20Northwest_Torgersen%2C%20Mason%2C%20Campbell.pdf

    Reply
  3. Invasive plants are the most common reason for pesticide use in many places in the Forest Service, and many of those plants occur in rangelands.

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