[permaculture] Prairies and Forests
peace at totalaccess.net
Wed Jul 10 11:40:01 EDT 2002
Thanks again, Mark, for all of your input. I am open to new ways of looking
at things and truly want what is best for the earth and its denizens. I
especially enjoyed your point about the rain shadow of the Rockies, which I
>> Bit of a stretch to blame desertification on burning IMO. Granted
vegetation will have an impact on climate, but the macro cycles of global
climate seem much more influential. <<
Climate change is indeed influential, and I've heard that since the 1850's
we've been in a warming, drying trend. Before that weren't we experiencing
a mini ice-age or cooling period since around the 1100's, and before that a
mid-evil warming trend?
I also believe that it's possible for us to accelerate and exacerbate our
present warming trend. Clearing the land by burning has no doubt been
affecting all of the macro cycles of global climate for the past 10,000
years, if not the past 100,000 years. It's probably time for us to
seriously ask ourselves if we want to keep burning the earth as a way of
managing it, or if we want to steer the earth away from fire adapted,
pyro-phillic plant communities.
>> Blanket condemnation of this method is just as absurd as the blanket
condemnation of cattle I hear far too often by folks who look only at feed
I apologize if my stance seems rigid. I believe that I have made it clear
that I am all for restoring grasslands and prairies. My concerns are about
how we do it. Fire may be right for some parts of the U.S.A. I think the
jury is still out when it comes to Texas, however.
Re Cattle: As Alan Savory points out very clearly, ungulates (bison,
camels, horses, mammoths, rhinoceros(?) all once native to North America)
are essential for the biological decomposition of organic matter in brittle
landscapes - brittle meaning long dry spells where organic matter is
desiccated by the sun and either blows or washes away; brittle lands also
have little or no build up of organic soils without the ruminant gut of an
ungulate. This to me translates that they play an important role in the
natural landscape as well as in our diets and economy.
However, since I cannot find any historical mention of naturally occurring
fires, at least in Texas, I have a much harder time embracing the use of
controlled burning across Texas prairies. WI is certainly different than
Texas, so for that region my concerns are with the recommended frequency of
burning the same piece of land. Once every seven years is too often, IMO -
that's what's recommended by the USNRCS in Texas.
>> This is where we part company fairly decisively. Prairie is open
grassland. Savannah is mixed prairie and trees at low density. Woods are
primarily tree dominated. These are distinct plant communites and the need
for all three is apparent when one looks at the fauna each supports. <<
Yes, the term prairie has many a set definition of which there is really no
arguing with. Words take on meaning independent of the original user's
intent and that is just the way language evolves. My point, is that there
should be some discussion about what the French explorers meant when they
coined the words prairie and motte (island of trees) as the entered Texas,
why they used the term prairie rather than grassland or savanna (a Spanish
term) and whether or not there can or needs to exist a name for an ecotonal
system which includes both grassland and woodland in its composition.
Prairies in Texas are a rolling mosaic of grasses and trees until you hit
the Caprock Escarpment just south and east of Lubbock, TX which then gives
way to the High Plains - a true plain, meaning that it is flat, featureless
(very few trees), and according to some definitions semi-arid. The High
Plains of Texas have been referred to as the Sahel of North America, the
leading southern edge of the Cetral Grasslands.
Across much of Texas, however, grasslands and woodlands are so interwoven it
really becomes counter-productive to attempt to untangle the two. This is
exactly why the French Explorers coined the phrase prairies when they
arrived in Texas, to distinguish them from plains and grasslands..
>> It [intensive, rotational grazing] is not however all that easy to do in
prairie systems, much simpler to use C3 grasses and annual C4's. <<
In lou of ungulates? I'm just learning about the differences between C3 and
C4 plants. The reference is to pathways for photosynthesis (PS) that
involve Carbon molecules, relate to the placement and behavior of stomata,
seasonal temperatures and night time or dark PS pathways? One is made up
more of forbes and brushy species and the other composed more of cool season
>> Hi Stanton's book, "Grasses and Grassland farming" He agrees with you
on burning big time. <<
Much thanks for the reference. You can be sure I'll track it down.
>> I believe the Rocky Mountain rain shadow has an awful lot of influence
here [Re: the drying out of the continent over the past 500 years]. Your
conclusions are based on faulty premises. <<
An excellent and fascinating point about the rain shadow. FYI, once upon a
time there was a tropical rainforest in the Rockies. My guess would be that
it was on the Pacific side. Here's a link to the article from the N.Y.
My conclusions are based on what I've heard from Bill Mollison regarding the
disappearance of the Anasazi Americans and the desertification of the South
Western U.S.A. since the early 1600's. Indications of man made
desertification are the suaro cactus which is supposed to be growing with a
scrub forest around it but now stands alone and is no longer reproducing,
the disappearance of the giant beaver in the South West, and the absence of
perennial water in the Sonora Desert - "Sonora" referring to the "sound" of
the water that once flowed through the Sonoran landscape.
My conclusions are also based on extrapolating from the experiences Alan
Savory had (recounted to me first hand) when he went into the interior of
Rhodesia, now Zimbabwe, and managed a program to slaughter all of the wild
ungulates in order to introduce homesteads and domestic livestock. Savory
says the waterways literally fell apart without the hoof action of the
ungulates and the vegetation dried up and blew away without the moist
fermentation of their ruminant guts. This experience is what set him on his
path towards Holistic Management. Compare that to the continental
eradication of North America's bison (herds over 100,000 strong that took
two days to pass at a trot on horseback) and the implications are huge.
There was also the Mid-West's dust bowl phenomena in the 1930's, which our
generation tends to quickly forget about. How much soil, species diversity
and bio-mass did we loose as a result of that, how much have we lost since?
Less than 6% of the earth's land mass is true hyper-arid desert, occurring
at two points of latitude, one in the northern hemisphere - Northern Mexico,
the African Sahel, Steppes of Mongolia(?), the other in the southern
hemisphere - the Chilean Andes, Australia(?). Much of the land we now
consider to be desert is really degraded arid and semi-arid grasslands,
degraded mainly by fire and agriculture. North Africa used to be the bread
basket of the Roman Empire, now, due largely to agriculture, it seems to be
merely an extension of the Sahel.
Desertization as opposed to desertification is the naturally occurring
migration of the true hyper-arid deserts of the earth, resulting from
planetary climate change. True deserts move very slowly and when talking in
terms of millenniums neither increase nor decrease in area significantly.
Desertification is the result of human disturbance and is quickly converting
most of the earth's arid and semi-arid grasslands into desert. Point,
being, I wouldn't underestimate mankind's ability to turn grasslands into
deserts, especially with a fire brand in his hand.
>> And turn the prevailing continental wind direction. Good luck. <<
It's documented that woodlands themselves our a source of precipitation.
The O18 molecule is found in rains that originate from the transpired water
from trees. The O16 molecule is from evaporated sea water and often doesn't
make it all the way to the continental interior. So the majority of the
rain in the interior of a large continent such as ours comes from trees. As
you mentioned, the Rocky Mountains wring (via topographical uplifting) most
of the water out of the air from the west, without the coastal forests there
would be much less precipitation in the Central Grasslands.
I can only surmise that with a robust coastal forest along the Gulf of
Mexico and the Pacific Rim we could increase the amount of rainfall and
humidity of the continental interior. Let's keep the grasslands but aim for
cooling and re-humidifying the planet.
>> Re grassing the central plains before the ogalala aquifer is blown might
be a bit more pragmatic and much more stable than trying to grow trees in a
I'm all for regrassing the Central Grasslands and protecting the aquifers.
Let's do it right, though, and make the most out of those areas already
cleared of trees and native grasses.
> >I've been following this topic [the effect of burning on insects] on the
prairie mailing list. It seems to be a double edged sword.
Meaning, it can be used as an argument either for or against the use of
controlled burning. Some use the increase of the insect population,
resulting from a fire, as a reason to burn, while I'm hearing warnings from
others that you can severely set back the insects if you don't leave them
some sanctuary. In other words a burn wipes out a lot of the insects it
moves over - whether the insects are able to quickly recognize is a risk
factor based on the knowledge and experience of those executing the burn. A
risk I'm leery to take.
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