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  • From: Mark <mpludwig@facstaff.wisc.edu>
  • To: permaculture@lists.ibiblio.org
  • Subject: Re: [permaculture] "thirsty " trees....
  • Date: Tue, 03 Sep 2002 10:06:21 -0500

At 07:59 AM 9/3/02 -0500, you wrote:
Hi Mark,

Just dug up some interesting snippets from the Pc design manual...

p.435, "Many [perennial grasslands], in fact are treeless areas established
during periods of icecap retreat, and have never established as forests,
although both soils and climactic factors will permit forest establishment.
Other grasslands are maintained by fire (natural, from lightning strikes; or
managed from human interference) against forest invasion."

p.435, "while a forest may have a visible "standing crop' of 207 t/ha, and
grasses only 7 t/ha, below the ground forests produce 184 t/ha of organic
matter to the 345 t/ha of natural prairie in equivalent soil / climate
regimes (Foth, 1984, based on other studies).

Soil depth in some of these historic grasslands is also phenomenal. Those of you who wonder how industrial ag maintains itself dispite it's madness should look here. 4 meters of prime A horizon lets one abuse the land for generations without paying much penalty. Except dieing of cancer early. I have one of Foth's soil science texts, I'll have to crack it open again....

p. 142, "The composition of the atmosphere is the result of reactive
processes, and forests may be doing about 80% of the work, with the rest due
to oceanic or aquatic exchange."

Hmmm. I thought there was a bigger contribution coming from the oceans. I remember seeing something on fertilizing the ocean with iron to boost the carbon sink effect there and bulk up the sea food production. What will the monkey people think of next ;<)

Lots of room in their to fill in the blanks, but helps to provide some actul
numbers.


Kirby


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Mark P. Ludwig
Poultry Research Lab
University of Wisconsin -Madison
608-262-1730 WK
608-846-7125 HM





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