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Clearing Forests Of Dead Wood Prevents Massive CO2 Emissions

| Thursday June 12th, 2008 | 14 Comments

woodb.jpgIt’s a known fact that trees are only temporarily carbon sequesters and that by the time they start to rot, all the nasty material gets transmitted back into the atmosphere again. So why not prevent this? Thus far we’ve been held back from doing so because intervening into the natural cycle somehow doesn’t feel right. But if we only tidied up one sixth of all the tree wastage lying around on the forest floors, we’d be nearing the carbon levels emitted by burning fossil fuels.

That’s quite a compelling idea. Climatologist Ning Zeng who works at the University of Maryland, published a paper describing the impact of clearing up forests on a the Carbon Balance and Management Journal website recently. The article, now flagged ‚Äòhighly accessed’, was picked up by various other journals in no time.
It must be said that the numbers – Zeng made his calculations on the basis of national US forests and CO2 data- are enough to spark anyone’s interest. Zeng’s says that to relieve forests of some of their excess debris, could lead to a recurring carbon sequestering of 10 gigatons of carbon a year. Trees and plants are believed to scrub the air free of some 60 gigatons of carbon a year. Most of that gets emitted back into the atmosphere when living organisms decompose.
Removing one sixth of the debris before it sets out to rot away might be a hugely efficient way to prevent greenhouse gas emissions, says Zeng. So long as enough woody debris is left on the forest floors to feed new cycles and to maintain bio systems, this is a feasible solution. The dead wood is best stored air tight underground. That way a continuous carbon sink is created. Every square kilometer of forest would fill trenches of 10×25 meters in size and 10 meters deep. Some 10 million of those would have to be dug every year to store 5 billion tons of carbon at a cost of $14 per ton worth of buried wood.
The proposal will trigger odd associations because something natural is proposed to be treated as if it’s a chemical. And in some ways the proposed interaction (if not interference) with forests’ bio rhythms is risky to say the least. Nevertheless Zeng’s argument is no waste of time because the scientist has analyzed all the factors involved. Including the types of soil and their reactions to types of wood. And he admitted to New Scientist that in some cases, the creation of methene gases won’t be prevented. Methane is known as one of the worst greenhouse gas types. This indicates that extreme care should be taken before big mistakes are made. Also, burying a biomass like trees and plants will inevitably attract termites which would mess up the project by puncturing holes in the airtight burial chambers. That’s not to speak of the natural habitats of some animals that you might ruin by clearing out wood.
But on the other hand the advantage of Zeng’s proposal is that if it’s well executed, it’s highly efficient. To date there’s hardly any technology that could match up to a 100% efficient burial of biomass with such greenhouse gas reductions. You could also argue that it’s very likely that managed forests likely offer plenty of evidence that not all human interference in the natural cycle is bad.


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  • Gary

    Just bear in mind, this was one of the silly ideas the bush admin used to justify massive logging. Plus, basically trees falling down and dying is a carbon neutral process – they cannot release more CO2 than they absorbed during their lifetime. It also takes a long time for trees to decompose – it’s not like they plop over and then release a bunch of CO2. Plus, old growth forests work very differently and it would be REALLY BAD to go around pulling all the dead logs out. Responsible forestry can go a long way, but clearing everything out is not necesarily responsible forestry.
    Pablo talked about this a while ago check it out

  • http://www.AskPablo.org Pablo

    Gary said: “trees falling down and dying is a carbon neutral process – they cannot release more CO2 than they absorbed during their lifetime.”
    When the decay happens in the absence of oxygen, or anaerobically, rather than turning into CO2, methane is created. Methane is 23 times more harmful to the climate than CO2. So technically it is possible for a tree to have a net positive GHG impact.

  • http://amplifiedgreen.wordpress.com angelique van engelen

    Gary, thanks for your comment.
    Clearing out the forest of one sixth of the material can in my opinion not be a bad idea. Have you ever compared a kempt forest with and unkempt one? One sixth is nothing, believe me, even if it’s only leaves it would be a sane idea.
    In terms of decomposing trees, I don’t think that Zeng proposed that. Airtight conditions prevent decomposing. What I particularly like about Zeng’s idea is that it’s a recurring CO2 sequestering. Nature could help us here whilst we think of different solutions. Massive logging is never a good idea, and it’s not what Zeng appears to propose.

  • Dave Shires

    Concept! Can dead material be removed in a relatively non-disruptive manner and used for building material and/or biofuel? That’s a huge business idea if someone can figure out how to pull it off.

  • http://solicitorbulgaria.com solicitor in bulgaria

    Even better than burying the wood is to turn it into charcoal and put it in the soil: http://en.wikipedia.org/wiki/Terra_preta

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  • http://amplifiedgreen.wordpress.com angelique van engelen

    Hey guys,
    I guess these are all great ideas. Let’s hear from Mr Zeng himself!
    Angelique van Engelen

    • Les Kantor

      Ning Zeng’s proposal is both insane and evil. Carbondioxid is not a pollutant, but a clean gas and the most important natural plant food. We should continue to convert coal, oil and natural gas into carbondioxid, releasing it into the atmosphere to promote plant growth. Contrary to “concensus” CO2 is in short supply, as we only had access to a fraction of the total amount of plant material buried under. Unfortunately we can not produce new carbondioxid.
      Please consider the catastrophic; over 50,000 km²/annum increase of barren desert on our planet and the resulting decrease in rainfall, as we continue to deforest the planet. We need all the carbondioxid we can get to promote plant growth, particularly trees, by the trillions. Yes, we have arrived to such a critical point of deforestation, now we are facing water shortages.(Large trees could evaporate several hundred litres of water a day under optimum conditions.)
      Please tell Mr Ning Zeng to keep his hands off carbondioxid destruction. He should find an honest way to earn a living.

  • http://www.hipinvestor.com Wil Keenan

    Hey all,
    I was just reading this article in the latest Wired magazine. They seek to dispel popular methods and preconceptions of what being green actually is. I would love to know your thoughts. Their first topic discussed concerning clearing dead woods. “Inconvenient Truths: Get Ready to Rethink What It Means to Be Green” (link: http://www.wired.com/science/planetearth/magazine/16-06/ff_heresies_intro)

  • http://amplifiedgreen.wordpress.com angelique van engelen

    Just heard back from Mr Zeng,
    He’s on holiday until end of July but I will report some more on his work then.

  • Gary Gilmore

    Forget burying the wood in air tight containers to keep it from decomposing. There is an easier way. Carbon composed 50% of a piece of wood. The remaining 50% is composed of hydrogen and oxygen with trace amounts of potasium, nitrogen and other stuff. If you heat this wood, the hydrogen and oxygen are driven off which can be burned for energy production. By controling the atmospheric oxygen available to this process, the resulting by product is charcoal. Charcoal is basically inert and will not decompose over the centuries. Charcoal could be buried or better yet, applied to agricultual land as a soil admendment that increases the tilth of the soil. This has been used in the past by indians in the Amazon basin (pre columbian)

  • dan cignoli

    Quick question – I have a wood burning stove with a double burn feature. When we were visited by a Sierra Club rep. he stated that decomposing trees release more toxins into the atmosphere than burning wood and that burning wood releases less that gas or oil. Today I read a letter to the editor in a local newspaper who feels his neighbor, who burns wood, is putting his health at risk. Any comments

  • Roger Therrien

    The real bottom line is that you actually need real living forests to store carbon naturally. Protect our national park and forests to keep carbon check. Keep some trees in your yard even if you have to rake in the fall.

  • s.nandeshwore singh

    yes, I agree decomposition of biomass in forest emit greenhouse gases.