[Terrapreta] C02 Tree Capture - how much carbon dioxide do trees really capture?

[Sean K. Barry]

Hi Michael,

I have seen Erich's quote on the available agricultural residue waste potential.  As well, in papers by Dr. Lehman I think , too.
This type of biomass is currently annually produced and it eventually decomposes and re-enters the atmosphere as CO2 and other gases in short term.  It it is carbonized, this prevents its carbon release to the atmosphere for a much longer term than even carbon in a forest stand. 

Growing stands of forest do not turn over as much carbon as they hold, or respire annually as much CO2, but some older mature forests can slowly reduce carbon fixation.  Decomposition in the forest trash will outpace new growth in older mature forests.  So a forest may hold a lot of carbon, but it changes its role as a "net fixer" versus "net producer" of terrestrial carbon emissions as it matures.

Attacking residual waste biomass (natural, human and animal wastes, etc), which are renewably produced annually, in my opinion looks for more forward towards sustainability, than does harvesting whole forests.  Replanting those forest would be an absolute requisite for sustainability with that plan.  Using the waste biomass streams does not require the replanting efforts.

Let the tress hold and give what they have in terms of carbon.  They have other uses than charcoal.

We have -5 degree F weather (-20 C) with about 8" of dry snow cover.  Up here, the albedo of trees snow, cloud shading, water vapor GHG effects, winter time air pollution, wind, "Alberta Clippers", and temperature inversions are all in play now.  Global Warming is "happening" inside "the cooler" up here in Minnesota, USA, this winter, so far.  I think temperate forests have a lower albedo than tropical forests.  Snow plows and my car run and start, fueled with B2 biodiesel, here in Minnesota temperatures.

Regards,

SKB
  ----- Original Message ----- 
  From: Michael Bailes<mailto:michaelangelica at gmail.com> 
  To: Terrapreta<mailto:terrapreta at bioenergylists.org> 
  Sent: Friday, December 14, 2007 6:32 AM
  Subject: Re: [Terrapreta]C02 Tree Capture - how much carbon dioxide do trees really capture?


  As far as I can see tropical forests do store CO2 and help global cooling.

  Despite a couple of promising research papers I don't thing the jury can yet decide about what happens in temperate forests.

  there are other issues involved not just CO2. trees exhale a lot of water  vapour (the major green house 'gas') and the level of this in the air is rising. 

  Then there is the albido effect.
  Do all forests absorb or reflect light?
  In Australia I would go for reflect.

  Then there are wildfires contribution to planetary Co2.
  (Australian forests should be regularly burnt to manage them properly.) 

  Then there is the soil micro-organisms and what they are exhaling

  The University of Western Sydney has started on a long term study of Australian tree growth trying to measure and control as many variables as possible. 

  To produce char we have billions of tonnes of waste. erich knight quotes a figure somewhere.
  After we burn that  maybe then we might start on the forests.:)?
  I would hope by then solar panels on every roof would replace burning coal for electricity. 
  MA
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