Standing trees better than burning ones for carbon neutrality

DURHAM, N.C. — The search for alternatives to fossil fuels has prompted growing interest in the use of wood, harvested directly from forests, as a carbon-neutral energy source.

But a new study by researchers at Duke and Oregon State universities finds that leaving forests intact so they can continue to store carbon dioxide and keep it from re-entering the atmosphere will do more to curb climate change over the next century than cutting and burning their wood as fuel.

“Substituting woody bioenergy for fossil fuels isn’t an effective method for climate change mitigation,” said Stephen R. Mitchell, a research scientist at Duke’s Nicholas School of the Environment. Wood stores only about half the amount of carbon-created energy as an equivalent amount of fossil fuels, he explained, so you have to burn more of it to produce as much energy.

“In most cases, it would take more than 100 years for the amount of energy substituted to equal the amount of carbon storage achieved if we just let the forests grow and not harvest them at all,” he said.

Mitchell is lead author of the study published in the peer-reviewed journal Global Change Biology Bioenergy. Mark E. Harmon and Kari E. O’Connell of Oregon State University co-authored the study.

Using an ecosystem simulation model developed at Oregon State, the team calculated how long it would take to repay the carbon debt – the net reduction in carbon storage – incurred by harvesting forests for wood energy under a variety of different scenarios.

Their model accounted for a broad range of harvesting practices, ecosystem characteristics and land-use histories. It also took into account varying bioenergy conversion efficiencies, which measure the amount of energy that woody biomass gives off using different energy-generating technologies.

“Few of our combinations achieved carbon sequestration parity in less than 100 years, even when we set the bioenergy conversion factor at near-maximal levels,” Harmon said. Because wood stores less carbon-created energy than fossil fuels, you have to harvest, transport and burn more of it to produce as much energy. This extra activity produces additional carbon emissions.

“These emissions must be offset if forest bioenergy is to be used without adding to atmospheric carbon dioxide concentrations in the near-term,” he said.

Performing partial harvests at a medium to low frequency – every 50 to 100 years or so – could be an effective strategy, O’Connell noted, but would generate less bioenergy.

“It’s a Catch-22,” she said. “Less intensive methods of harvesting release fewer emissions but yield less energy. The most intensive methods, such as clear-cutting, produce more energy but also release more carbon back into the atmosphere, prolonging the time required to achieve carbon sequestration parity.”

Given current economic realities and the increasing worldwide demand for forest products and land for agriculture, it’s unlikely that many forests will be managed in coming years solely for carbon storage, Mitchell said, but that makes it all the more critical that scientists, resource managers and policymakers work together to maximize the carbon storage potential of the remaining stands.

“The take-home message of our study is that managing forests for maximal carbon storage can yield appreciable, and highly predictable, carbon mitigation benefits within the coming century,” Mitchell said. “Harvesting forests for bioenergy production would require such a long time scale to yield net benefits that it is unlikely to be an effective avenue for climate-change mitigation.”

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The research was funded by a NASA New Investigator Program grant to Kari O’Connell, by the H.J. Andrews Long-term Ecological Research Program, and by the Kay and Ward Richardson Endowment.

14 thoughts on “Standing trees better than burning ones for carbon neutrality”

  1. Golly gee!!!!! I guess we won’t be clearcutting forests, solely to burn for energy production!! Instead, we’ll just keep burning the mountains of slash generated from thinning and fuels reductions projects in big piles on the landings.

    c|8^(

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  2. This study seems like one of those where people 1) propose something people couldn’t and wouldn’t do, and then 2) analyze why it’s a bad idea.

    But this seems hard to believe:

    “The take-home message of our study is that managing forests for maximal carbon storage can yield appreciable, and highly predictable, carbon mitigation benefits within the coming century,”

    from where I sit, we can’t afford to manage forests for “maximal carbon storage” because our puny efforts at management can’t maximize very much at all. Forests are expensive to manipulate, and our manipulations can not work through a variety of unexpected and unpredictable change agents- which makes investments for some future situation pretty questionable, particularly in this economic climate.

    Perhaps forests and their relations with humans look predictable when one examines them through simulation models. My life experience says perhaps not so much. Plus isn’t cimate change itself, and our future policies around it, unknown and unpredictable?

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    • It is more than ironic that this study was funded by the Kay and Ward Richardson Endowment. I was working as a student researcher doing cultural resource inventories for OSU Research Forests when the long-time pioneer family tree farm was passed from father to daughter to OSU — and for the expressed purpose of long-term management and student research. I was flat-out informed by the OSURF Manger (my boss) “not to get involved.”

      The land was a gold mine of Indian and early pioneer history; including pioneer family tree farm history requiring Sec. 106 evaluation, if it were federal and not school (even land grant?). No inventory was taken or allowed. The land was clearcut, the pioneer community dump raided for antique bottles, and the land sold within years of the bequeathment. And the money frittered away on crap like this (sorry, JZ):

      “The take-home message of our study is that managing forests for maximal carbon storage can yield appreciable, and highly predictable, carbon mitigation benefits within the coming century,” Mitchell said. “Harvesting forests for bioenergy production would require such a long time scale to yield net benefits that it is unlikely to be an effective avenue for climate-change mitigation.”

      I’m wondering if this is something about tenure, or pal reviewing a grant, or something like that? I’d lay odds. Managing forest land for carbon was a dumb idea in 1991, and it remains an even dumber idea that we’re still wasting valuable research dollars on such a concept to this time, more than 20 years later: http://www.NWMapsCo.com/ZybachB/Reports/1993_EPA_Global_Warming/index.html

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      • What did I miss? Why are apologizing to me?

        If ever there was a “Jabberwokey”, I’d say the carbon thing is it…

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        • JZ: I was catching up on my blog reading after being gone a couple of days, and I had just responded to (and agreed with) your “lack of professionalism” comment on another string — I was assuming that the phrase “crap like this” might also be construed as unprofessional in that context, and was just covering the bases in advance.

          Too, I think that one should “Beware the Jabberwock” when dealing with “riparian zones,” “critical habitat” and “ecosystem services,” among other political concepts — “managing a forest for carbon storage” might be the most frumious of the lot, however.

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  3. In their scientific paper, “Target Atmospheric CO2: Where should Humanity Aim?,” Dr. James Hansen and others advised unequivocally:

    “If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm.
    An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting agricultural and forestry practices that sequester carbon.

    “Reduced deforestation and degradation is the forest mitigation option with the largest and most immediate carbon stock impact in the short term per (hectare) and per year globally….”
    (from: Climate Change 2007: Mitigation of Climate Change. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 541-584).

    On Economics (“Can we ‘afford’ to attempt to prevent irreversible catastrophic climate change?”) and, unpredictability, (“Should we attempt action given an unpredictable dynamic and an unknowable political policy outcome?”) — these have easy answers when ethics enter into the equation.

    Regarding economics, there is no quantifiable measure of the consequences of failure to attempt to stem our emissions nor the consequences which will predictably occur to all future life on earth.

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  4. I believe you that Hansen said it; they may have even said it “unequivocally”; the problem is that they can’t possibly know that. No one can. 385 to 350? Why not 391.6?

    Where I sit, the only “deforestation” comes from large fires – and “degradation” is not a scientific term, so it doesn’t really help me understand what we should be doing or not doing.

    In my opinion, the scale at which people write global assessments is not easily transferred to a local land management decision. Simply stated, the average of ecosystems and practices is not equal to ANY specific ecosystem and practice.

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  5. I like Figure 1 in the paper that is presented here. Carbon storage in unharvested stands clearly levels off at a certain point in time. Capture that C in forest products (dimensonal lumber) and start that cycle over. Also not mentioned much in this paper is the amount of atmospheric carbon that is used in a regenerating stand.

    Tree are the anwser…lots of young thriving ones that is.

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  6. Hey Smokey, “Lots of young thriving trees” seems like 1) not such good wildlife habitat for countless species of wildlife and fish and 2) like an impending over-load of fuels for fires.

    Also, when combined with your suggestion to “start that cycle over” (ie log out the mature trees) this sounds like not a great option for soil productivity and overall soil health, among many other issues.

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  7. I thought you were talking about Carbon Matt? I was at least…

    There is a place for everything Matt. Thriving tree plantation sucking up carbon, Old-growth stands, wilderness, etc. Just know that the forests you strive to protect aren’t taking up much atmospheric carbon. Sure they are storing a bunch, but as decay sets in old-growth forest emit a bit of carbon too.

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    • Yep, we have, oh, about a BILLION “protected” dead trees producing more powerful GHG’s, until they are consumed in the next inevitable wildfire. There’s always the novel concept of matching tree densities to annual precipitations but, does anyone REALLY want THAT?!?!? Modern projects are always designed to have multiple benefits, for multiple stakeholders, including the general public. I tend to think that increased forest resilience is a part of most people’s “desired future condition”. Preservationism embraces catastrophic “re-balancing”.

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  8. Sharon,
    “Degradation” is a valid scientific descriptor of a general condition, and is used by your own agency (USFS) quite often as in the following USFS publication “Climate Change and Forests” (I apologize for using all caps for emphasis but those are my only options in this blog) http://www.fs.fed.us/global/topic/climate_change/welcome.htm

    “…deforestation and land DEGRADATION generate a significant percentage – approximately twenty percent – of total global greenhouse gas emissions.”

    “Forested lands and grasslands are rapidly disappearing around the world for a variety of causes, including agricultural clearing, catastrophic fires, poor land management and destructive logging practices. This phenomenon is occurring despite the vital importance of forests for storing carbon, conserving biodiversity, and providing clean water, food, medicine, fuel and income to more than two billion people, including an estimated 350 million indigenous and tribal peoples. The trend is not encouraging: worldwide, deforestation and land DEGRADATION are expected to rise. Increases in global food prices will drive even further conversion of forested lands to agriculture. And, in the big picture, these changes will correspond to a parallel increase in the rate of greenhouse gas emissions.”
    ( “degradation” is used frequently throughout the publication but unfortunately, this publication is devoted to paying lip service to the international dimensions of forest management, and little of its green washed language has been applied to our national forests, and especially, here on the Tongass.)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Given the urgency of preventing further feedbacks and the gravity of “irreversible”, this cannot be about parsing decimals, and justifying inaction based upon lack of specificity as your comment emphatically claims.

    As David Archer points out the persistence of our CO2 emissions in our atmosphere is measured in centuries and millennia.(Archer, David. 2009. The long thaw: how humans are changing the next 100,000 years of Earth’s climate. Princeton Univ. Press.)

    This is about a moral imperative to work towards a goal of rapidly reducing our emissions. It is not about declining to stop a runaway train because you want to fully understand the (unwritten) manual before applying the brakes.

    It turns out our forests have played an important role in preventing the runaway condition quite well for millennia, but much less so in a degraded state. Past mismanagement combined with predicted drought scenarios across the American west are effectively resulting in deforestation. Our national forest system represents an excellent carbon bank in which to invest hope and carbon for the future of the planet.

    The post and my previous comment refers to just two of many papers, a fraction many others on the topic follows:

    Hamburg, S.P. 2000. Simple Rules For Measuring Changes In Ecosystem Carbon In Forestry-Offset Projects. Mitigation and Adaptation Strategies for Global Change 5:25-37

    Harmon, Mark. 2007. Letter to California Air Resources Board. Comment on Forest Protocols. Online at: http://www.arb.ca.gov/lispub/comm/bccomdisp.php?listname= forestghg07&comment_num=22&virt_num=22.

    Janisch, J. E., and M. E. Harmon. 2002. Successional changes in live and dead wood carbon stores: implications for net ecosystem productivity. Tree Physiology 22 (2-3):77-89.

    Law, B. E., O. J. Sun, J. Campbell, S. Van Tuyl, and P. E. Thornton. 2003. Changes in carbon storage and fluxes in a chronosequence of ponderosa pine. Global Change Biology 9:510- 524.

    Luyssaert, S., E. -Detlef Schulze, Annett Borner, Alexander Knohl, Dominik Hessenmoller, Beverly E. Law, Philippe Ciais and John Grace. 2008. Old-growth forests as global carbon sinks. Nature 455: 213-215.

    Mackey, Brendan G, Heather Keith, Sandra L. Berry and David B. Lindenmayer. 2008. Green carbon: the role of natural forests in carbon storage. Part 1, A green carbon account of Australia’s south-eastern Eucalyptus forest, and policy implications. The Fenner School of Environment & Society, The Australian National University. 48 pp.

    Nabuurs, G.J. and R. Sikkema. 2001. International Trade in Wood Products: Its role in the land use change and forestry carbon cycle. Climatic Change 49: 377–395.

    These papers are not the full list by any means (to say nothing of many others on ocean acidification) but which shed light on the mechanism by which we are killing the planet and insights as to how to avoid accelerating our demise.

    There is a well established international scientific consensus which ascertains we face an urgent situation. Your agency recognizes this– why don’t you?

    Opposition to this international consensus includes you, and a well established powerful minority ( the “1%”) who are aided and corrupted by the phenomenal fossil fueled profits providing the means of congressional influence to maintain business as usual. These same corporate/congressional interests are profiting off of policy half-measures which are recognized to be worse than doing nothing, due to lulling the public into thinking we are actually doing something efficacious. The opportunity costs of exceeding tipping points in the unknowable time frame we face are immeasurable.

    We have a general understanding of where we need to focus our planning and policy decisions. Building a transition economy of National Forest management with a PRIORITY on carbon sequestration and ACTUAL forest restoration of its severely degraded state is an excellent place for the USFS to reverse its course of past and present mismanagement.

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  9. David, just because people put the word “degradation” in their papers, doesn’t mean it’s defined.

    In the “climate change and forests” piece you quoted..

    “Forested lands and grasslands are rapidly disappearing around the world for a variety of causes, including agricultural clearing, catastrophic fires, poor land management and destructive logging practices. This phenomenon is occurring despite the vital importance of forests for storing carbon, conserving biodiversity, and providing clean water, food, medicine, fuel and income to more than two billion people, including an estimated 350 million indigenous and tribal peoples. The trend is not encouraging: worldwide, deforestation and land DEGRADATION are expected to rise. Increases in global food prices will drive even further conversion of forested lands to agriculture. And, in the big picture, these changes will correspond to a parallel increase in the rate of greenhouse gas emissions.”

    So it is important to provide fuel to people but not if there are “destructive logging practices”.
    One person’s catastrophic fire is another person’s good and natural fire.
    You don’t have to have spent time reviewing FSC certification standards, as I have, to figure out that one person’s degradation is another person’s responsible forest management providing fuel and income to people.

    I stand by my assertion that “degradation” is in the eye of the beholder, and not a scientific term.

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