[Terrapreta] CO2 rising

[Brian Hans]

Sean,
   
  Forest ecosystems hold more carbon at any one time more than a grassland, you are correct. Not sure why you think I am disputing this? Forests are a very good way to store fixed solar energy, likely the best way. Im pro tree. I pro more forest. I think they are more valuable than given present day credit. Infact, I'll go so far as to say that in the near future, trees will enter another golden age for a huge number of reasons. I think people would be wise to invest in trees. I love trees and some of my best friends are trees. Forests hold wealth for the individual as well as global life. I hope this settles the myth that I seem to hate trees or find them useless...its completely the opposite. 
   
  But...(there is always a butt) a forest is a summery of many years of solar fixing. Lets use a local resource as some data examples. http://www.rs-inc.com/downloads/FOE%20Forest%20Biomass%20Final%20Report.pdf  According to this data (pg 13-14) ...Wisconsin forests yield about 2-6t/a/y. Im not sure where you get your 700t/a figure but @ 6t/a/y ...a forest will take 111 years to reach that mass (minus root weight which is because of previously stated R:S ratio is ~ .2 = .4-1.2t/a/y of roots + there is the aspect of leaves y/y digesting away to CO2.) But then we get to the grassland y/y. 2-8t/a/y of production y/y + root biomass production for a native ecosystem and a stand of switchgrass does 6-10 t/a/y and miscanthus upwards to 15 t/a/y just south of us @ UI U-C. http://www.miscanthus.uiuc.edu/  C4 grasses are going to be more efficient at fixing carbon and producing biomass than dicots anyday of the week and blows away pine. 
   
  One of the beauties of trees is that you can harvest them anytime... grass is a 'cut it when its ready' crop. But at yields of 15t/a/y (25t in the tropics) ... grass makes up for its deficiencies. 
   
  A forest holds more carbon at any given time but doesnt fix more carbon year over year than a grass or ag land. So Im not sure why the data we have been discussing would be useless...I suppose its only useless if you use a camera like perspective...for a grassland, you need a motion picture camcorder. 
   
  Brian Hans
  

"Sean K. Barry" <sean.barry at juno.com> wrote:
            Hi Brian,
   
  You stated R:S ratios for grassland at 4:1 and for forestland at what? 1:2.5 or something like that?  Just looking at R:S your conclusion is correct I think, that grasslands hold more carbon in the soil than forest lands do.   But, as far as how much carbon gets held in and on how much area of land, this R:S shoot argument is USELESS!  You can see why, right?
   
  Try this ... 10t of C in grass and 40t of C in grass roots <= your example.  How about 200 t of carbon in tree roots and 500 t of C in tree trunks, branches, stems, and leaves.  Which is a bigger number?  700 t of carbon of 50 t of carbon?
   
  Do you kind of see how BOTH your R:S numbers can be valid and the comparison of them says NOTHING about the relative amounts of carbon held in forest land versus grassland?  Do you see how even with a larger R:S ratio, an acre of grassland DOES NOT hold more carbon than an acre of forest land (10 < 200)?
   
  How is that mat feeling?
   
  Regards,
   
  SKB
   
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