[Terrapreta] New Scientist: Burying trees to fight climatechange

[Ron Larson]

TerraPreta list etal:

    Sean asked several questions today in message received at 2:21 Denver time:  My answers in Bold below.  Note this is talking about an article by a Prof. Ning Zeng - not the Swedish article on forests.

Hi Ron,

5. [RWL1}   I think this tree burial approach could have legs in competition with biochar - because it is apt to be cheaper.  

[Sean1}  This one you might need to explain.  How can burying trees deeply into the soil be cheaper?! 

[RWL2a:  I wasn't clear enough.  I used "apt" because I am not sure of the economics.  But we are only talking about cutting and moving the logs a short distance (no over the road haul) and a bulldozer can make a relatively small hole pretty cheaply and cover and move on.  The article suggests one percent of the land ditsurbed every five years.  I don't think biochar can compete economically on that level.

Sean:   Do you want to discount the value of increased soil productivity to zero?

[RWL2b:  No - and that wasn't part of the argument in the article.  I hoped to make your exact point when I wrote: 
6.  But the benefits appear lesser - because whole tree burial is much like putting the trees in mine shafts (but cheaper) - no continuing, out-year benefit stream. 

Sean:  Do you need to ignore the potential economic benefits of harvesting renewable carbon neutral bioenergy?  Do you really believe that this world can afford to ignore the economic benefits of reducing CO2 concentrations in the atmosphere? 

[RWL2c:  Same response.  I wasn't clear enough.  I don't want to ignore these aspects.]

 Sean:  Do you really think less energy is required to dig a deep hole to put trees into and refill it than to incorporate charcoal into the top 15 cm of soil?  

[RWL:   Yes.   but I don't think one should take that path, just because it takes less energy (including human energy) and might make more money if we value Co2 sequestration too little.

Sean:  When did you decide that biochar had now advantages other than a possible carbon sequestration mechanism?

[RWL2:  About 6 years ago, if I understand your question.]

RWL1:  Based on the first year results, tree burial wins, I'll bet.

Sean:  I'll take that bet, any day.  All I would need to do is pyrolyze the trees, harvest some energy, leave some charcoal, and never bury any of it deeply and I can guarantee that I will sequester more char for less expense than those who dig deep holes and bury whole trees.  The only significant problem to solve here is to pyrolyze the trees without releasing and Methane.

[RWL2:   The key words in my sentence were "first year".  Tree burial locks up 100% of the CO2 (or C) for a long time (according to Zeng).  Biochar locks up 50% at best. Zeng also argues that mature trees are not taking CO2 out, and that you don't want to let them fall and rot in the forest.  These points are also in his favor.  Not sure how you win the bet.

    My hope is that Zeng will learn about biochar (I could find no mention of biochar by Zeng anywhere, including his personal home page) and come to the same conclusion that you and I (and near everyone on the list) have.  The soil improvement aspect is critical. 
     I wanted to comment on the Zeng paper In support of Laurens and Peter below, because the burial concept was new to me and a potential competitor to TP/biochar and because i had found the original paper.   If  the carbon credit community give attention only to the first year C reduction, I still feel his appraoch will be cheaper.  I repeat "first year".]     Ron
  ----- Original Message ----- 
  From: Sean K. Barry 
  To: Peter Read ; terra pretta group ; Laurens Rademakers ; Ron Larson 
  Sent: Saturday, May 03, 2008 2:21 PM
  Subject: Re: [Terrapreta] New Scientist: Burying trees to fight climatechange



  Regards,

  SKB
    ----- Original Message ----- 
    From: Ron Larson 
    To: Peter Read ; Sean K. Barry ; terra pretta group ; Laurens Rademakers 
    Sent: Saturday, May 03, 2008 9:40 AM
    Subject: Re: [Terrapreta] New Scientist: Burying trees to fight climatechange


    Peter, etal  This is to report a bit more on the Ning Zeng article noted below.

    1.  The technical article behind the popular article is available  free at:http://www.cbmjournal.com/
    2.  I found the article to be well written - and the concept new to me.
    3.  Prof. Zeng knows his subject well - and there is much on forests and the soil carbon cycle that can be useful to terrapreta list members
    4.  There is no mention of terra preta / biochar in either the Zeng article or the (on-line) journal (CBM=Carbon Balance and Management).  One can register for free and leave messages (as I did about TP)
    5.  I think this tree burial approach could have legs in competition with biochar - because it is apt to be cheaper.  
    6.  But the benefits appear lesser - because whole tree burial is much like putting the trees in mine shafts (but cheaper) - no continuing, out-year benefit stream.
    7.  I have no disagreements with the comments of Peter, Sean, and Laurens below, but think the low-cost argument might prevail.
    8.  I took up the New Scientist $4.95  4-week trial offer before learning the above - but now can search theirweb-site going way back in time.  Might be worth it to some others.
    9.  Laurens quotes Lovett on Zeng doing the same thing as terra preta.  Lovett is not correct, but I am glad Lovett linked the two concepts.  
    10.  We on this list should do what the previous commenters have suggested - we need an economic comparison.  
    11.  This requires major attention to out-year economic benefits of biochar.  Based on the first year results, tree burial wins, I'll bet.  This is an apples-oranges situation.

    Ron

        
      ----- Original Message ----- 
      From: Peter Read 
      To: Sean K. Barry ; terra pretta group ; Laurens Rademakers 
      Sent: Friday, May 02, 2008 9:07 PM
      Subject: Re: [Terrapreta] New Scientist: Burying trees to fight climatechange


      I recollect this being called "pickling logs" in the early 1990's
      Deep burial would release large quantities of carbon through oxidation of disturbed/exposed soil organic matter - one aspect of the concern over 'carbon debt'  raised in the recent science paper by Fargione et al.
      Avoiding soil disturbance though low- or no-till cultivation is part of developing understanding of best practice land use improvement.
      A thing I have wondered about is, suppose you just scatter biochsar on the soil surface, does it get carried down by rain, bugs, worms etc ?  One proposal form pastoral land is to feed biochar to mixing into cattle cake and then let nature do the rest.  Any ideas on how well that would work?
      Cheers
      Peter
        ----- Original Message ----- 
        From: Sean K. Barry 
        To: terra pretta group ; Laurens Rademakers 
        Sent: Saturday, May 03, 2008 2:19 PM
        Subject: Re: [Terrapreta] New Scientist: Burying trees to fight climatechange


        Hi Lorenzo,

        I suspect that burying trees "deeply" into the ground would require more energy than putting charcoal into or onto the topsoil.  There would be NO agricultural benefit for having the tress buried into the ground and there would be NO energy harvested from that carbon rich biomass.

        So, burying trees by comparison to charring biomass and adding the charcoal to the soil seems to not take advantage of some pretty worthwhile benefits;  improving food agricultural production, harvesting needed renewable energy instead of continuing to burn fossil fuels, and doing all of this while also sequestering carbon into soil for thousands of years.

        Regards,

        SKB
          ----- Original Message ----- 
          From: Laurens Rademakers 
          To: terra pretta group 
          Sent: Friday, May 02, 2008 8:11 PM
          Subject: [Terrapreta] New Scientist: Burying trees to fight climate change


          Original here (subscription required):
          http://environment.newscientist.com/channel/earth/mg19826542.400-burying-trees-to-fight-climate-change.html

          Mongabay's summary:

           Could cutting down trees and burying them help fight global warming? An article in this week's issue of New Scientist suggests so. 

          Ning Zeng, an atmospheric scientist at the University of Maryland in College Park, tells New Scientist that thinning forests and burying "excess wood" in a manner in which its didn't decay could sequester enough carbon to offset all of our fossil-fuel emissions. 

          "Zeng gives an example of a plot of 1 square kilometre (100 hectares), with the excess wood from 1 hectare of woodland buried deeper than 5 metres and down to 20 metres," writes Richard Lovett of New Scientist, referring to Zeng's research published in Carbon Balance and Management. "He calculates that this could sequester 1 tonne of carbon per hectare - using that land to grow trees would sequester 1 to 5 tonnes, depending on the age of the forest and the type of tree." 

           "He estimates that offsetting all of the world's current emissions would be achievable with a workforce of one million people - substantially fewer than those already employed in the forestry industry in the US alone," Lovett continues. "Even so, to offset all our emissions, most of the world's forests would have to run a wood burial scheme." 

          New Scientist notes that Zeng's idea is not a new one - ancient indigenous groups used a similar approach known as biochar to enrich the nutrient-poor soils of the Amazon rainforest. 

          "More than 500 years ago Amazonian people were creating almost pure carbon by smouldering their domestic waste and letting it work its way into the soil. This earth, known as terra preta ('black earth') remains to this day," Lovett writes. "Ancient farmers had no idea that they were sequestering carbon, of course, but they did know that adding biochar to the soil hugely increased its quality." 

          Lovett cites a modern example in hydrothermal carbonization, a process which chars organic material under pressure. He says the technique could eventually be used on an industrial scale and may qualify for carbon credits, assuming it could avoid generating methane, another potent greenhouse gas. 

          http://news.mongabay.com/2008/0430-soil_carbon.html

          -----------------------------------------

          Interesting concept. We could use an economic comparison of biochar systems in agriculture as compared to Zeng's idea of just burying the trees deeply into the ground.

          Cheers, Lorenzo
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