OSU study finds old-growth forests provide temperature refuges in face of climate change

BBush Old Growth
Wow! Imagine that. Oregon Public Broadcasting has the story.

Old-growth forests in the Northwest have the potential to make the extremes of climate change less damaging for wildlife. New research out of Oregon State University shows complex forests do a surprisingly good job of regulating temperature on the ground – even compared to fully mature tree plantations.

“On a sunny day, if you were sitting underneath them, you’d get a similar amount of shade,” says study co-author Matt Betts, an Ecologist at OSU.

But the kind of forest makes a big difference on temperature.

“The more structurally complex the forest, the more big trees, the more vertical layers – the cooler it was,” he says.

The research showed differences as much as 4.5 degrees on warm days. Old growth forests also held in heat during cold weather. Overall, these forests have a moderating effect on temperature extremes.

One reason, researchers suspect, is that tree plantations, even mature ones, don’t have nearly the understory material – small trees, shrubs, ground cover – as more complex stands. Nor do these single-age plantations have a lot of big trees – unlike old growth stands.

“We think one of the mechanisms causing this is thermal inertia,” Betts says. “That takes these trees longer to warm up and longer to cool down. And that could be providing some of the buffering capacity of these older forests.”

Betts says these stands of old growth could provide refuges for temperature-sensitive wildlife in the face of climate change.

“It gives us some hope that how we actually manage our forest, can influence positively those species that are declining,” he says.

The study was published Friday in Science Advances.

20 thoughts on “OSU study finds old-growth forests provide temperature refuges in face of climate change”

  1. “It gives us some hope that how we actually manage our forest, can influence positively those species that are declining,” he says.

    After all the reasons endlessly repeated here for the necessity to actively “manage” (by some form of cutting or-really-bad-things-are-sure-to-ensue…), this seems to suggest, to “manage our forest” actually includes the practice of simply leaving it alone to manage itself (you mean, like it has for eons…?)

    Not covered in the list cited here however, is “management” impacts on mycorrhyzial fungi below ground and the overall plant and animal species abundance and diversity within intact, undisturbed soils.

  2. The authors write that “We conclude that the substantial influence of vegetation structure on microclimate presents the opportunity to manage for conditions that favor the persistence of biodiversity.”

    Note the use of the word “manage.” To me, that might mean a range of management options, such as thinning or fuels reduction to increase resistance/resilience to wildfire. The authors do not mention fire or other natural disturbances, but they do mention timber harvesting:

    “Our findings indicate that management practices that result in single-species, even-aged plantations are likely to reduce the thermal buffering capacity of forest sites, potentially limiting the availability of favorable microclimates for some species.”

    • Logging to save habitat form fire has been thoroughly debunked, especially when the habitat we are trying to save is dense, fuel-rich, and structurally complex. The Wildlife Society (TWS) peer review of the 2010 Draft Recovery Plan for the Spotted Owl. The draft plan called for extensive logging to reduce fire hazard (“inaction is not an option”). TWS used state-and-transition model to evaluate the effects of opening dry forests to reduce fire hazard versus the effects of wildfire.

      The results of running the model with 2/3rds of the landscape treated leads to open forest becoming predominant after a couple of decades, occupying 51 percent of the forested landscape, while mature, closed forest drops to 29 and 24 percent of the Klamath and dry Cascades forests, respectively (Appendix A, Figure 5, shows the Cascades). Treatments that maintain open forests in 2/3rds of the landscape put such a limit on the amount of closed forest that can occur, even if high severity fires were to be completely eliminated under this scenario, there would only be 35 percent of the landscape occupied by closed forests. In contrast, to the extensive treatment scenario, treating only 20 percent of the landscape reduces mature, closed canopy forest by about 11 percent (Appendix A, Figure 6).
      One justification for the extensive treatment scenario promoted in the 2010 DRRP is that it is needed because of increased fire hypothesized to occur under climate change. By doubling the rate of high severity fire by 2050 with 2/3rds of the landscape treated, closed canopy forest is reduced to 25 percent in the Klamath compared to 60 percent without treatment and 23 percent in the dry Cascades compared to 54 percent without treatment.
      Under what scenario might treatments that open forest canopies lead to more closed canopy spotted owl habitat? The direct cost to close forests with treatments that open them is simply equal to the proportion of the landscape that is treated. This reduction in closed canopy forest can only be offset over time if the ratio of forest regrowth to stand-replacing fire is below 1 (5-8 times more fire than today), and shifts to above 1 with the treatments (and most or all stand replacing fire in treated sites is eliminated, as modeled here). Another scenario that allows closed forests to increase would be if treating small areas eliminated essentially all future stand replacing fire, not only in treated areas, but across the entire landscape. This scenario obviously relies on substantially greater control over fire than is currently feasible, and it would increase impacts of fire exclusion if effective.

      In sum, to recognize effects of fire and treatments on future amounts of closed forest habitat, it is necessary to explicitly and simultaneously consider the rates of fire, forest recruitment, and forest treatment over time, which has not yet been done by the Service.

      The potential impacts of fuel treatments on spotted owls are not considered. … We also know little about the impacts of fire, yet this has been treated as a major threat, leading to proposing more fuel treatments. However, it is uncertain at this time which is a bigger threats, fires or treatments to reduce risk of fires. … If the plan intends to use the best available science to describe ongoing impacts to spotted owl habitat, information and literature about disturbances to reduce fuels should be included.
      … there has been no formal accounting of how closed canopy forests can be maintained with the widespread treatments that are being proposed.

      The Wildlife Society 2010. Peer Review of the Draft Revised Recovery Plan for Northern Spotted Owl. November 15, 2010. http://www.fws.gov/oregonfwo/Species/Data/NorthernSpottedOwl/Recovery/Library/Documents/TWSDraftRPReview.pdf.

      Se also, Dennis C. Odion, Chad T. Hanson, Dominick. A. DellaSala, William L. Baker, and Monica L. Bond. 2014. Effects of Fire and Commercial Thinning on Future Habitat of the Northern Spotted Owl. The Open Ecology Journal, 2014, 7, 37-51 37. http://benthamopen.com/toecolj/articles/V007/37TOECOLJ.pdf

      • 2ndlaw,

        You have cherry-picked your sources, sources that see a burned old-growth stand and as good as an unburned one. I disagree. Here’s another view:

        “Strategic, proactive hazardous fuels treatments have proven to be a safe and cost-effective way to reduce risks to communities and forests by removing overgrown brush and trees, leaving forests in a more natural condition resilient to wildfires. When implemented strategically, at a meaningful scale, these treatments can make a crucial difference in the size, spread and severity of wildfires. They can improve the safety and effectiveness of firefighters and provide protection for a community or essential watershed that might otherwise see extensive loss.”

        — from the testimony of Christopher Topik, Director, Restoring America’s Forests, The Nature Conservancy, before the Committee on Energy and Natural Resources, United States Senate, June 4, 2013. Title of his presentation: “Proactive Forest Restoration and Wildfire Risk Reduction: A Responsible Investment for People and Nature.”

  3. We have wilderness areas for that. I see more wildlife in treated areas. The problem is that we have lost a lot, or almost all of our old growth savannah eco systems. Question: what did these areas look like before the first conifer trees invaded them. A management example might be : when restoring Aspen stands on Fed. land they always want to leave the old growth fir. But those trees are one of the reasons that conifer invasion occurs. Would it be more beneficial to Aspen and wildlife to remove them also? I think I know what some would say. None of us were there back then, so opinions probably don’t mean much. And progressively some of these studies are obviously skewed. The ironic thing is Montana universities are payed for by it’s resources such as timber, and these students aren’t told that by there professors. I have personally asked some and they were clueless. This whole issue isn’t as simplistic as some would portray. Hey, I made the decision not to have kids. A lot of huggers have them though. So there.

    • “The ironic thing is Montana universities are payed for by it’s resources such as timber, and these students aren’t told that by there professors.”

      Hi Pat: Do you have any documentation or numbers to back this up? I was able to find the this recent (2015) article about the land grant universities in Montana. Seems like a pretty small piece of the funding pie for these universities, which appear to have a total operating budget in 2016 of $1.538 billion. So I’m not sure it’s really accurate to frame it that “Montana universities are payed for by it’s resources such as timber” because that number is so very small compared to the entire budget.

      • Matt — I totally agree that the contribution of timber and other land grant resource revenues is a small percentage of the overall Montana university budgets, but I think there’s something to be said about the outsized influence of timber and resource companies. From funding endowments to anonymous contributions earmarked to certain university projects, their influence is prevalent and secret – I think the administrations give those funders virtual vetoes over some aspects of the university’s operations. And I’m sure that’s going on at other universities as well.

  4. However, that referenced “range of management options” results in often unaccounted, yet significant consequences as revealed by the USFS and others:
    (from) http://www.fs.fed.us/…fu-mycorrhizal-fungi-effects-from-mgmt-2012-04.docx

    “Annotated Bibliography of Information Potentially Pertaining to Management of Rare Fungi on the Special Status Species List for California, Oregon and Washington”

    “Soil compaction has been considered a principal form of damage associated with logging (48). Soil compaction degrades soil structure and restricts movement of oxygen and water through soil and reduces pore space for root penetration and production of feeder rootlets where mycorrhizae form”

    “As a generality, it appears that thinning reduces the species richness of the EM (ectomycorrhizal) fungal community within the forest/stand being thinned. Further, thinning effects to the EM community appear to relate relatively directly to thinning intensity. ”

    “Soil compaction has been considered a principal form of damage associated with logging (48). Soil compaction degrades soil structure and restricts movement of oxygen and water through soil and reduces pore space for root penetration and production of feeder rootlets where mycorrhizae form.”

    Then there’s the climate consequences of “management options” at a critical juncture in human history. We need the full range of services from intact old growth forests now, more than ever.

    Role of Forest Ecosystems in Climate Change Mitigation
    B.E. Law – Oregon State University, February 23, 2014

    “Comprehensive assessments are needed to understand the carbon consequences of land use actions, and should include a full accounting of the land-based carbon balance as well as carbon losses through the products chain. In mature forests, harvest for wood product removes ~75% of the wood carbon, and 30-50% of that is lost to the atmosphere in the manufacturing process, including the use of some of that carbon for biomass energy. The remainder ends up back in the atmosphere within ~90-150 years, and there are losses over time, not just at the end of the product use). These loss rates are much higher than that of forests. Full accounting of all carbon benefits, including crown fire risk reduction, storage in long- and short-term wood products, substitution for fossil fuel, and displacement of fossil fuel energy, shows that thinning results in increased atmospheric carbon emissions for at least many decades.”(end quote)

    The institutional bias of (plantation)”management” is made self-evident by claims of benefit which excludes the above sampling of consequences (and so much more), versus “management” which simply allows forests to be forests delivering the full-spectrum of irreplaceable services–( rather than relegated to mere crop status.)

  5. Assuming this research bears up under peer review/scrutiny, it only shows what I’ve long felt; nobody knows everything there is to know about anything. This holds true for those in the don’t-touch-the-forest camp as well as for those who’d manage everything in 40-year rotations.

    Given our society’s need for wood fiber, I’d think we need to see how we manage for wood production in a way that considers these temperature differences as well as the forest’s flora and fauna. I’m not convinced either the don’t-touch-the-forest or the 40-year rotation is the answer. For federal forests, long rotations might be the happy medium.

    I’ve seen some suggest that the temperature mitigating effects of old-growth is important for mitigating climate change! That seems quite a stretch since the amount of old-growth, both now and the past, covers enough of the Earth’s surface to have much more than a localized affect.

    It would have been interesting if the study also looked at places where the forest had been converted to other uses; i.e., shopping malls, suburbs, etc. though I suspect we pretty much already know the answer. What I mean is that there must be sufficient incentives for forest land owners to keep their lands in forest.

    • This is a bit off-target for this thread, but here’s a brief article from ClinmateWire….

      Bear poop helping Japanese cherry trees stay cool

      Published: Wednesday, April 27, 2016

      Bears might be helping Japanese cherry trees avoid climate change, spreading cherry pits uphill even as climate change heats up the trees’ established territory, according to a study in the journal Current Biology.

      As bears climb north to cooler ground, so are the trees, which are growing at higher elevations, found a study from the Forestry and Forest Products Research Institute in Ibaraki, Japan. Researchers gathered cherry pits from bear feces in the mountains west of Tokyo over a four-year period.

      “We studied cherry trees because their seeds were easy to track in bear feces,” said Shoji Naoe, an author of the study. “The cherry trees are at risk of population decrease from global warming, because they prefer cool habitats.”

      The seeds moved uphill an average of more than 300 meters, a shift that adds up to a 2-degree-Celsius temperature difference, according to the study.

      “That’s good news in the short term, but mountains eventually turn to sky, and cherries aren’t going to do very well in sky,” said David Westcott, a dispersal ecologist with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia (Bob Holmes, New Scientist, April 25). — PL

  6. (Re: “Given our society’s need for wood fiber, I’d think we need to see how we manage for wood production in a way that considers these temperature differences as well as the forest’s flora and fauna.”)

    Well over 90% of US timber production is occurring on private lands, most of which are managed as de facto tree plantations.

    Tree plantations host about 90 percent fewer species than the forests that preceded them. (Allen Hershkowitz, Bronx Ecology,2002, p. 75)

    (This begs the question, what is the highest and best use of the NFS?)

    “A notable tradeoff between water yield and productivity is expected to intensify under higher greenhouse gas emissions and associated climate change in the future, posing greater challenges to managing these lands and balancing these important ecosystem services.”

    So the implicit assumption that national forests are more important to fulfill a fractional national demand for wood fiber than for maintaining resiliency of myriad ecosystem services in the face of climate disruption does not address the very real threats we face.

  7. Wow. Reading all these comments shows that the one comment…’we don’t know enough about most things to know what to do, or not to do…’ is the real “answer”. But we must remember that these NATIONAL FORESTS were created for more than log/lumber production. In the long run, I suspect the production of clean, high quality water is going to be the best, most critical output these forests can yield. There are increasing products that can/will substitute for wood. But there is NO substitute for mountain water.
    On another vein, this posting helped me remember one very cold, snowy winter day in northeast Washington on the Colville NF, where I found a herd of 25-30 elk huddled under a canopy of OG cedar. Was it warmer, or was the snow depth the key attraction? Maybe both. Just wondering.

  8. So I am kind of getting the point. There are two views here basically.
    People who believe you can help a forest by managing it, combined with the social and economic necessity of taking care of our forests and the products that can come it, and that this is important for us as people.
    And people who believe basically that the forest will take care of itself and if all our forests were wilderness, that people and the environment would all be better off.
    Which doesn’t really leave much room for discussion between the two.

    • “And people who believe basically that the forest will take care of itself and if all our forests were wilderness, that people and the environment would all be better off.
      Which doesn’t really leave much room for discussion between the two.”

      Such a description suffers from a fatal reductionism of at least one side of this discussion.

      First, proper context:
      As minimally referenced in the article, old growth forests play an important role in the maintenance of micro climates, not to mention our carbon emissions and myriad other ecosystem services, not the least of which is a severely compromised fresh water supply across most of the American West. We now face a long-predicted, scientifically-predicated and validated, human-generated, planet-wide, existential threat to life as we know it. Given the immense risk of Anthropogenic Climate Disruption triggering irreversible climate-forcing positive feedbacks (several already set in motion) the only ethical, and sane response is for our full national and international cooperation towards an interruption to Business As Usual (BAU) — including the present unsustainable premises of neoliberal macroeconomic policy.

      “Discussion between the two,” (aka “Collaboration”) has centered around the maintenance of BAU, rather than its necessary, and fundamental interruption. A profound moral crisis exists when individuals knowingly ignore the “irreversible and irretrievable,” catastrophic consequences of their (in)actions. Such failures condemn our childrens’ and future generations to a hellish existence on earth. (50% of the CO2 we release today will still be present in our atmosphere over a century from now.)

      Second, there are significant differences between a (self-managing) old growth Wilderness forest and a commercially “managed” “forest,” (more properly referred to as a tree plantation.) Private tree plantations already provide well over 90% of the national wood fiber supply. There is no dispute that commercially-managed tree plantations cannot physically provide the full range of ecosystem services our old growth National forests could otherwise supply. The fractional component of national wood fiber commodity production presently coming from our NFS is not a “social and economic necessity,” no more so than fossil fuel production is an unchangeable “social and economic necessity.” Alternatives presently exist, but our planetary predicament is certain without a full spectrum cooperative interruption of BAU.

      Lastly, according to the best applied science, it is not too late to avoid planetary catastrophe by the interruption of BAU. But this will require a scale of national and international cooperation not witnessed since WWII. The currently-practiced “collaboration” being funded by foundations heavily invested in BAU and their term “collaboration” needs to be understood for what it was identified as during WWII: “traitorous cooperation with the enemy.”

  9. To me part of the problem is we have set aside 90% of our public forests, and 99% of our old growth and it still isn’t working that great. I am a believer in rural communities are important. If they aren’t healthy, then the urban areas won’t be either in the long run. “Everyone”, loves the country, just hardly anyone wants to live here, because their no jobs, but even worse, it’s also because there aren’t all the “goodies”. Our public lands belong to the people, not just the timber companies or Oregon Wild, but to all of us. And it sure would be nice as a forest dweller that those forest were more than just places for our urban cousins to persevere for their water and recreation.
    One note, before the Northwest Forest Plan, our private forests were a lot more diverse. The forest plantation, especially in the West, has come into dominance in the last 25 years. It is the direct result of 30% of the forest landscape, the private part, producing 90% of our nation’s wood fiber. It is neither sustainable or desirable.

    • “To me part of the problem is we have set aside 90% of our public forests, and 99% of our old growth and it still isn’t working that great.”

      As a rural resident of a once, “timber dependent” community (pop. ~3000) for the last three decades, I’m intimately familiar with the timber boom/bust reality vs. the timber industry’s fast and loose tales of “our urban cousins” (and other bad people) interfering with the promise of perpetual reruns of “the good ol days.”

      For obvious reasons, such “Once upon a time…” bedtime stories tend to avoid messy details which might inspire innocent questions. Questions such as, “but 99% of what?”, or “Daddy, what are market failures?”, or “What are ecological limits, globalization, automation and all those other bad dreams haunting us? Did those bad people make them too?”

    • The U.S. South’s forests are private and plantations. They account for 60% of the nation’s wood products production. Regardless of whether that’s “sustainable” or “desirable,” it’s certainly not due to the Northwest Forest Plan, which issued decades after the South’s forests had been converted to plantations.

  10. About 20 years ago at an Assoc Oregon Loggers meeting in Eugene, I heard John Beuter (OSU and Asst Secy USDA) ask industry folks how long the public would continue to put up with all the clearcuts, spraying, etc on private lands. It now appears longer than HE thought, as any casual observation of rural forests would show. I believe many of Sproul’s “urban cousins” would actually love to see forests — public and private — actively managed for naturalness, clean water, fish and wildlife, and, especially, mature forests. Wood products and these other goals are NOT mutually exclusive. But I think folks are pretty sick of seeing lands hammered in the pursuit of money (only) under the guise of forestry.


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