From: jc@sppip7.lkg.dec.com (John Chambers)
Newsgroups: rec.org.mensa
Subject: Re: Alien Intelligence (was Re: TIME TRAVEL)
Date: 7 Apr 92 21:05:22 GMT
Reply-To: jc@sppip7.lkg.dec.com (John Chambers)
Organization: Digital Equipment Corporation

|> >Then there were the North American plains, which recent  research  has
|> >suggested  had  a  yield  of  human-usable  food  around  an  order of
|> >magnitude greater than the farms that are there  now  (and  which  are
|> >still "mining" the prairie soils a century later).
|> ...
|> 
|> This is interesting--could you run some more details?  How was the prairie
|> maintained?  (I have an impression that fires were used.)  If ten times as
|> much food could be produced (I assume that's what you mean by "an order of
|> magnitude") maybe we should be thinking about changing the legal system.

Well, the few references I have are at home, but I can summarize.   As
for  changing  the  legal  system;  it  is  unlikely  to happen in our
lifetime.  Regardless  of  what  the  researchers  find,  our  society
basically  holds all such "primitive" societies in contempt, and isn't
about to adopt their methods.  But it is  interesting  to  study.   If
you're  interested  in details, you should probably contact your local
botany or paleoarchaeology professor.

There have been extensive studies of the prairie ecosystem for several
decades  now,  at  several  Midwestern  and Great Plains universities,
including the Universitiess of Wisconsin (where I was for  a  decade),
Illinois,  Indiana, Iowa, Nebraska, and so on.  There are experimental
prairies scattered across the plains,  with  the  constant  complaints
about  the  difficulties  in researching a system that really requires
millions of contiguous hectares to function properly.   But  much  has
been  learned,  and  a  lot  of  it  goes  against  many of the social
prejudices of Western Man.  (But what's new about that?  ;-)

First, some numbers.  As you no doubt know, agronomists classify soils
into  several  "horizons" (layers to the layman ;-); the upper horizon
is the "topsoil" which is typically 2-10 cm in most  farming  systems.
The  data available from the early 19th century, which is corroborated
by the results in the  experimental  prairies,  is  that  the  prairie
topsoil  ranged  from 50 to 150 cm in the moister areas.  That's not a
typo; the topsoil was really a meter or more  thick  in  much  of  the
prairie  area.  This topsoil, furthermore, had a relatively low "soil"
content; it was mostly tubers, bulbs, and other storage organs.   True
prairie  soils  tend  to have edible food available everywhere for the
cost of digging.

The modern agriculture on the plains has been basically "mining"  this
prairie  soil for the past century or so, and in most areas in is down
to 1/3 to 1/10 of the original thickness. It won't last much longer in
many  areas,  though some farmers are starting to face the prospect of
introducing soil maintenance.

Plants in typical  forests  and  agricultural  lands  tend  to  follow
closely  a  general  rule  that  there  is  roughly an equal amount of
biomass above and below the ground.   In  the  prairies,  90%  of  the
biomass was below ground, 10% was above ground.  And it was all edible
(except maybe for the stems of the brambles, and they have  some  very
nice fruit). BWT, only about 1/3 of the plant biomass was grasses; the
other 2/3  is  what  the  botanists  call  "forbs",  i.e.,  non-woody,
non-grass species.

The  system  was  maintained  was  by  fire,  which  was   set   quite
intentionally by the human population.  The primary motive was simple:
It kept out the trees.  The trouble with trees is  that  most  of  the
incoming  energy  goes into making wood, which is pretty much inedible
to all but a few insects and microorganisms.  Animal  life  in  mature
forests  tends  to be rather sparse, because the only edible foodstuff
is in the canopy.  It's good for squirrels and  some  birds,  but  the
productivity is rather low from the viewpoint of anything but a tree.

When  the  prairies  were  burnt, it had the effect of destroying tree
seedlings, and as a result all the incoming energy  went  into  making
edible greenery. The result was a large population of grazing animals,
which was the primary food of the humans  (plus  whatever  tubers  and
berries they felt like harvesting).

The  fires  also  had  another effect.  They made for strong selective
pressure to be the first plant up after  the  fire.   To  survive  the
grazers  and the fires and the intense competition afterwards, a plant
had to treat its aboveground parts as dispensible, and invest much  of
its resources in underground storage.  Thus the thick layer of tubers.
Incidentally, because fires were usually set in spring when there  was
lots  of  dry  material around, the prairie species tend to be slow to
come up in spring.  This was probably a minor defect in the system.

Contrary to the "Bambi" image of forest  fires,  the  descriptions  we
have  of prairie fires imply that the local animal life descended on a
fire in huge numbers.  The fires wipe out the cover  for  insects  and
small  mammals,  and the predators have a feast.  A prairie fire is no
big deal; you can run through a line of burning  grass  and  get  only
slightly warm.  Two or three cm down the temperature hardly rises. The
schools that keep experimental prairies get gangs of student  together
annually  for  the burns, and running back and forth through the fires
is a standard game. Similarly, predators like hawks, foxes and badgers
are  attracted  to  the smoke, and will dive right into the fire for a
tasty critter.  Burning wood is dangerous; burning leaves are not.

Some of the people studying the prairie system have tried  to  collect
archaeological data about human habitation. This is difficult, because
most of their raw material were biological, and  that  sort  of  stuff
doesn't last too well.  There are researchers claiming that there were
more people in North America in 1400 than there are now; mostly on the
plains.   This is an area in which more research is definitely needed,
of course. But their explanation is simple:  The prairie system was so
rich  in  foodstuffs that it easily supported a much higher population
than it does today.

The prairie system was quite strongly limited by climate. If it is too
moist, then you can't easily use fire to control the forests. Chopping
the trees out by means of tools is very  labor-intensive,  so  in  the
moister  areas  the  forests  could  dominate.  But the fires kept the
prairie system alive over at least twice the area that it  would  have
covered  without  the  fires.  There was only one species of tree that
could survive the prairie fires, the burr oak.  It wasn't that  big  a
problem,  especially  since it has one of the most delicious acorns of
any oak (which are mostly quite bitter from tannin).

In recent years, researchers have started looking  for  evidence  that
similar  systems  may  have  evolved  in other parts of the world.  In
several areas, they have found the evidence.  For instance, I heard  a
lecture  at  the U of Wisconsin about 10 years ago by a fellow who was
studying the pollen record in the bottom of lakes in the Amazon basin.
He  said  that  before  about  1500,  the  pollen  was  mostly  of the
savannah-type species that are now only found in the drier  south  and
southeast.   It  was  mixed with layers of dark stuff that on analysis
turns out to be soot.  His hypothesis  was  that  the  South  American
people  had  developed  the  same system as their distant relatives in
North America; when they were wiped out  by  European  diseases  about
1500, the fires stopped and the forest spread over the entire basin.

More recently, similar studies in central Africa and eastern Australia
have  turned  up  evidence  of repeated fires and lower populations of
forest species, up to about 1500 when the European  explorations  (and
diseases) started.

It's interesting to think about.  But I wouldn't expect our  legal  or
agricultural system to take any notice of it. The prairie system can't
work on a small scale of a thousand hectares or less.  It requires the
sort  of  communal  "ownership"  of  the  land  by all people that was
developed  in  North  America,  eastern  Africa,  and  Australia  (and
presumably  the  Amazon, though we have little knowledge of the social
system there prior to 1500).  The chance that  this  could  happen  in
America  is  about  the  same  as  the  chance that we will convert to
Communism.  We in the West have in  the  past  shown  ourselves  quite
willing  to  forego  a lot of efficiency to maintain our social order,
and there's no reason to expect  that  further  data  about  primitive
peoples  will  change anything.  Other kinds of agriculture (e.g., the
chinampa system of Central America) can  sneak  in  through  the  back
door,  but  an  inherently  big  thing like a prairie system may never
again happen in this  world,  unless  Western  Civilization  collapses
entirely, which isn't likely in the forseeable future.

Enough gab for today.  Let's see what sort of religious and  political
flames this generates...

[References?  We don't need no steenking references on Usenet! ;-]

Newsgroups: rec.org.mensa