Is the Amazon Forest a man made place?

[Jon Miller]

read about it Sava

JM

[Dinner]

Originally posted by Last Conformist
I find it hard to believe that advanced agriculture was wiped out in Amazonia when it wasn't in places like Mesoamerica and Peru, where the European impact was more drastic.

I suppose I should tell the uni library to by Mr Mann's book ...

I guess the population wasn't as large as Peru or Mexico and the cities were more dependent upon large scale public works which were hard to maintain without the critical mass of people. Agriculture didn't disappear in the Amazon though the cities did and now all we see is slash and burn type agriculture. Interestingly enough slash and burn seems to have been made possible or at least greatly expanded by contact with westerners. With stone axes it could take 6 months to clear a plot large enough to support 1-2 families but with iron axes it can be done in a week. So right when the cities were being abandoned new technology came to enable a new though less enviromentally stable way of life.

There were lots of examples of cities and large towns being abandoned in the new world due to disease, war, and who knows what other reasons.

[VetLegion]

Sava, read about it

[Last Conformist]

Originally posted by Kuciwalker
Doesn't Europe have less "unsafe" geography? It doesn't seem to have as many earthquakes or hurricanes...

Well, southern Europe has it fair share of earthquakes and volcanic eruptions. Most of the rest of the place does combine a benign climate with geological stability.

In the western bits, this is combined with an exceptional amount of navigable rivers* and coastal trade-routes - a environmental determinist would say that Europe's rise to preeminence was pretty much inevitable after the introduction of the heavy plow that enabled the exploitation of its agricultural potential.


* Unbelievably, the rivers and canals of Europe accounts for nearly half of the planet's navigable waterways.

[Dinner]

Originally posted by Brachy-Pride
It was in (the territories of) Argentina in the south and the usa in the north + caribean islands, where the non farming cultures were located, which is funny since the missisipi plains and the pampas are 2 of the 3 most fertiles areas in the world.

There were the cities of the mound builders in the Mississippi and as far north as Ohio which farmed using such crops as corn, beans, squash, tobacco, and local small seed grains. Those small seed grains are much less productive then large seeded grains like wheat, rice, millet, or even corn but if they're all you have then you use them.

The nonfarming natives of Noth America were in northwest Mexico through the rockies (and west to the Pacific) and most of the tall grass praires of the great plains. I guess without draft animals or metal tools it is very difficult to break up the sod that makes up places like the Pampas or the Great Plains.

[Last Conformist]

@Oerdin: Some Amazonian groups have carried on swidden agriculture without iron tools into the present, so however helpful iron axes are, they can't be strictly necessary.

Also, I'd be rather skeptical of the figures of sizes for towns of settlements by early Spanish explorers. Early 16th C Spaniards claim, frex, that the Maya city of Canpech (modern Campeche) was as great as any in Europe, which just isn't true.

But again, I should get reading the book ...

[Dinner]

Originally posted by VetLegion
Interesting read Oerdin. What is this pottery based farming method called, I'd google more about it?

The author called it "terra preta" or "terra preta de indio" (dark earth of the indians?) and claimed that it covered a lot more of the Amazon then was previously thought; some where between 10% and 25% of the total basin area. It is basically large scale organic compositing with lots of broken pottery mixed in to it. I believe the presence of the cloth pottery expanding and contracting to loosen the soil is really only found in the Amazon.

After a google search these are a few links I found about terra preta:

http://www.geo.uni-bayreuth.de/bodenkunde/terra_preta/

http://www.geo.uni-bayreuth.de/bodenkunde/terra_preta/Zech_abstract.html

http://www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretahome.htm

http://www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretanetwork.htm

Lastly here is a really great link from the BBC about terra preta and the existance of large cities in the Amazon:

http://www.bbc.co.uk/science/horizon/2002/eldorado.shtml

[Dinner]

From the BBC link:

Archaeologists have surveyed the distribution of terra preta and found it correlates favourably with the places Orellana reported back in the 16th century. The land area is immense - twice the size of the UK. It seems the prehistoric Amazonian peoples transformed the earth beneath their feet. The terra preta could have sustained permanent intensive agriculture, which in turn would have fostered the development of advanced societies. Archaeologists like Bill Petersen, from the University of Vermont, now regard Orellana's account as highly plausible. But if the first Conquistadors told the truth, what became of the people they described?

20th century techniques of farming on cleared, torched rainforest - so-called slash and burn agriculture - have never been sustainable. With the vegetation burned off, the high rainfall soon leaches all the nutrients out of the soil. Research has shown that even chemical fertilisers cannot maintain crop yields into a third consecutive growing season, yet terra preta remains fertile year after year.

Again, Orellana's accounts offer potential insight. He reported that the indigenous people used fire to clear their fields. Bruno Glaser, from the University of Bayreuth, has found that terra preta is rich in charcoal, incompletely burnt wood. He believes it acts to hold the nutrients in the soil and sustain its fertility from year to year. This is the great secret of the early Amazonians: how to nurture the soil towards lasting productivity. In experimental plots, adding a combination of charcoal and fertiliser into the rainforest soil boosted yields by 880% compared with fertiliser alone.

Supposedly the partially burned wood which is mixed in with the organic fertilizers bonds to the nutrients and prevents the rain water from leaching them away. This rich soil attracts bacteria and fungus which multiply in it thus further enhancing the fertility of terra preta. This sounds like a great way for people in tropical places to organically expand the productivity of their farms.

[child of Thor]

Originally posted by VetLegion
.......
This is a myth actually. The Amazon forest consumes almost all oxygen it produces. So it's in no way the lungs of anything.

True, the term is rather 'lose'. Still soaking up gazillions of Co2 is another very important aspect of Huge forests - and is a large factor in global warming(which most scientist do believe is happening).

So more trees = good
Less trees = bad
(you dont hate trees do you? )

[Dinner]

My understanding is that trees take in CO2/give off O2 during the day when they are creating sugar but give off CO2/take in O2 during the night.

Believe it or not algea and other green autotrophic sea life are the real lungs of the Earth. It's just a numbers game since these critters get the first 10-30 feet of the world's oceans to live in and the seas cover 3/4 of the Earth.

[Last Conformist]

Forests tend to bury carbon in the ground, thus functioning as CO2 sinks.

("Tends" is the operative word - I'm fully aware this isn't the case for all forests.)

[child of Thor]

well the algea and the trees get my vote - they do good work

Still i'm trying to remember this area in south america where they've found huge(like miles long) what appear to be irrigation channels running straight through the jungle. Where they have cleared the land for cattle ranches you can see it best in a plane.

Its just the point of it being possible to man-make an enviroment as large as the Amazon jungle - if the scale of these irrigation channals were as large as the acheologists believed, it would have meant a very large scale deforestation project in this period(whatever period preceded the early Aztecs).

It was just something on one tv show i saw - i've never heard anymore about it.

[Odin]

Algae are the world's lungs, but terrestrial vegetation is very important intermediaries in the carbonate cycle that regulates CO2 levels on geologic time scales because of it pumping CO2 into the soil. this increases the amount of CO2 that eventually gets trapped in limestone on the ocean floor.

[Barnabas]

so, hispanics have been great gardeners since time immemorial

[JohnT]

So... the Amazon rain forest is just one big GM experiment, writ massive and out of control?

I'm just saying!