[Terrapreta] Some clarifying answers

[Sean K. Barry]

Hi Eric,

You asked a question below that I saw in a previous post from Ron Larson.  The units, "tons of carbon per hectare per year" (tC/ha/yr), is used for measuring the amount of carbon taken from the atmosphere (an offset to CO2 emissions) by plant growth.  It refers specifically to the weight of carbon in CO2, which inspired by plants grown over one hectare of land, during one growing season.  As long as the plant growth is not combusted, eaten, or decomposed, then the carbon the plants contain is locked up (sequestered) into the molecular bonds of the plant material.

Fast growing young forests are good carbon offsets, because the bulk of the carbon which they take in as CO2, stays perched in the trees above and swollen into the roots systems below many hectares of land.  When forests get older, they are no longer net carbon sinks, because they have decomposition of the plant material which puts CO2 back into the atmosphere.  A forest can sequester lots of carbon for a good twenty years.  Terra Preta soil has carbon which stays almost permanently, certainly with half-life of many thousands of years.

Both plant growth and other carbon sequestering technologies ("offsetting technologies") are carbon sinks.  They all do it in chunks measurable as weights of carbon over areas of land and durations of time.  Some are just better at it than others.  I hope this clarifies.

Regards,

Sean K. Barry
Principal Engineer/Owner
Troposphere Energy, LLC
11170 142nd St. N.
Stillwater, MN 55082
(651) 351-0711 (Home/Fax)
(651) 285-0904 (Cell)
sean.barry at juno.com<mailto:sean.barry at juno.com>
  ----- Original Message ----- 
  From: Ron Larson<mailto:rongretlarson at comcast.net> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Cc: Erich Knight<mailto:shengar at aol.com> ; Ronald West<mailto:westr9 at comcast.net> 
  Sent: Tuesday, March 06, 2007 9:11 AM
  Subject: [Terrapreta] Some clarifying answers

  d. (in a third message) "I still don't understand why any offsetting technology, which does not place carbon in the soil, would be characterized by a tons per hectare per year designation, I find this confusing. Wouldn't it be clearer if offsets were described as just tons per year? 
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