Humans may have helped the decline of rainforests

Discussion in 'Earth Science' started by arauca, Feb 11, 2012.

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  1. arauca Banned Banned

    Geochemist Germain Bayon and colleagues from the French Research Institute for Exploration of the Sea in Plouzané, France, analyzed marine sediment cores representing the last 40,000 years, taken from the mouth of the Congo River. The team looked for geochemical markers such as hydrogen, which correspond to rainfall levels that affect natural levels of erosion, and they also looked at potassium, which erodes quickly, and aluminum, which is more immobile.

    The core samples revealed evidence of severe chemical weathering starting around 1,500 BCE, a time that coincided with a period in which Bantu-speaking tribes arrived in the area, having migrated from regions near what is now the border between Nigeria and Cameroon. Chemical weathering in samples dating before this era was consistent with the changes in rainfall patterns, but by 1,000 BCE the weathering seen was decoupled from the rainfall evidence.

    Chemical weathering can be caused naturally by rainfall and normal erosion, but it can be accelerated by deforestation and intensive agriculture. Since the climate was changing at the time and becoming drier, a reduction in chemical weathering would ordinarily be expected rather than the peak actually found.

    The Bantu people were farmers and had developed iron-smelting techniques. Iron-Age Bantu archaeological sites have yielded ceramics, furnaces, tools, the remains of agricultural products, and a variety of iron artifacts.

    Bayon and colleagues suggest, in their paper published in the journal Science, that the farmers’ clearing of land for agriculture and their iron smelters, in addition to the changing climate, would explain the collapse of the rainforest and its replacement by grasslands and savannas in the region. The researchers were unable to estimate to what extent human activities were responsible, but they suggest the evidence from the sediment core shows human influence was “already significant.”

    The paper’s authors say their results were unexpected, but reveal that humans can have an enormous effect on the environment. While their findings do not necessarily contradict the prevailing theories, because the changing climate enabled the farmers to practice agriculture in the region, the Buntu farming practices themselves then changed the patterns of soil erosion.

    The study could have implications for the current situation in the world’s largest rainforests in the Amazon, where large areas are being deforested, largely for cattle or soy bean farms, and for industrial purposes and road construction. This, together with the current changes in climate, could also result in a rapid disappearance of remaining rainforests and their replacement by grasslands, with a massive resultant loss in biodiversity, and feedback changes to the local climate. Rainfall in the Amazon is already reducing, and there have been major droughts, notably in 2005 and 2010.

    Is that true England was defolresting its tree their cooking and warming . , but finally they realized the damage and so they ( brits ) derided to use coke.
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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Although widely believed this is not the main cause of the deforestation. Every few years some reporters will come and photograph the cattle in what was rain forest. This helps keep the false causes seeming valid.

    What is the main cause is the fact that the well off in developed countries prefer beautiful wood furniture. Their demand causes a single mahogany tree to be worth more than a year of pay at the minimum salary. Many who live in the rain forest don´t earn even that, but trap and sell by the road sides parrots etc. (all illegal of course) for their cash income. They hunt and fish etc. too, but these activities use the rain forest so most don´t want it destroyed.

    A tiny fraction of the locals, however, do cut down a valuable specimen tree, despite the possibility of years of jail time.* Then to hide their middle of the night crime, they set fire to that part of the forest. It will eventually burn itself out, perhaps with the smoke particles nucleating rain fall.

    The soil is very poor, and the burnt over area is covered with half burned stumps and logs. Some local may try to scratch a living farming on the fire "cleared" area, but trapping wild game is usually more profitable. Eventually some wealth absentee owner will bring in heavy equipment to properly clear the land and may spend a little on fertilizer to grow some grass, and then add his cattle. Soy and sugar cane have too low a value per pound to ship 500 or so miles to market, but beef is more valuable per pound and can be profitably raised in the already cleared (burnt over) areas, but not if you must clear forest to do so (which is mainly illegal anyway and unless a politicain etc. gets him spending decades in not very plesant jail).

    Brazil has the world´s toughest enviromental laws - is world leader in Green Technology. Makes plastic (see diagram below) and motor fuel from renewable sources instead of petroleum. Less than 10% of its electric power releases CO2, etc. About 10% of Brazil´s power comes from the heat of burning crushed sugar cane, but that is a slightly net negative release of CO2 as not all of the carbon removed from the air even comes the sugar plant. (The heat required for distilation is only a small part of the heat released as the crushed cane is burned.)

    I could be wrong, but do not think there is any commercial scale growing of soy in land that was once rain forest. Most of that is on fertile land 500 or more miles to the south.

    Summary: if you (1) own beautiful wood furniture and (2) want to know who is destroying the rain forest, go look in a mirror. But it is more comforting to blame the local poor trying to make a meager living.

    * One simple, poor man living in Sao Paulo, cut some bark off a tree to make a tea for his sick wife. - He went to jail, but was later released after press coverage exposed his "crime" and compared it to the well connected clearing large tracts on the shore of water resevoirs for their private camps, where nothing can legally be constructed.

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    All seats for next world cup (Brazil 2014) will be "sugar seats."
    Brazil is leading the world down a new, non-oil path to a green future. the main stadium in Amsterdam is now replacing its old seats with "sugar seats" - I.e. made of polyethylene that was made for sugar cane sugar as shown in figure above.
    Last edited by a moderator: Feb 11, 2012
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  5. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Is someone saying that humans have not helped the decline of rainforests?
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  7. Search & Destroy Take one bite at a time Moderator

    I helped indigenous people slash and burn large areas of rainforest just so that they could afford electricity. Every year around festival time the families with land chop down 20-30 trees just so they can afford to go to the festival. Owning land with trees is like having money in the bank. Unfortunately they grow too slow to be sustainable. As Billy T said, someone comes up and picks up the lumber, processes it, and it eventually becomes furniture. And oh that mahogany is some nice wood - there's nothing nicer than a big dark Mahogany table that still has its natural shape.
  8. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Note, that they did not need to burn large areas of the forest, just to hide illegal cutting of one very valuable tree.

    Brazil too, about two years ago, understood the Amazon is to big to prevent the cutting of valuable trees by someone very poor, when foreign demand makes that tree more valuable than a full year´s wages. Thus, now some parts of the Amazon can have valuable trees selectively cut under license and there is no need to burn 100 or so acres to hid the no longer illegal crime.

    PS in post 2 I forgot to mention that in addition to hunting and fishing, they collect "Brazil nuts" - they only grow wild in the company of other types of trees. There have been a few attempts to plant groves of brazil nut trees and collect the nuts more economically, but all have failed - the tree will ONLY grow among others in the wild!
    Last edited by a moderator: Feb 13, 2012
  9. Search & Destroy Take one bite at a time Moderator

    Ah yes, we were never worried about authorities where I was. I was far enough off the beaten path. Burning was more for efficiency than anything else, as we could convert acres into farm at the same time.

    I'm sure you've heard about the big dam project under works. I wonder your opinion on it. I signed the petition already as it's the least I can do.

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  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Yes this is one more example of the pain natives suffer when larger and more advanced civilization have wants that conflict with their more primitive life styles. No advanced civilization that I know of has much to be proud of when looking back on the effects the advanced society produced for the native one.

    By and large, modern Brazil is much better than most. These Indians will be (I am sure) relocated on land equally as large, which will support their life style at least as well as the land they will lose to the rising waters.

    Israel has the worst of all records in this respect. They have completely destroyed the Bedouin culture and rounded up the small fraction not now dead into one of three concentration camps. (They are called "enclosures" when the Hebrew is translated into English, not "concentrations camps" for obvious reasons.)

    They are in the very worst part of the Negev desert - so little rain that wells only produce strong brine. - Israeli trucks bring in drinking water, but not one goat is permitted within the enclosure - this for a proud, peaceful, nomadic, goat-herding people who had Ottoman Empire deeds to the land the Israelis just took with no compensation paid. (Deeds are not valid as they are older than Israel.)*

    Officially Israel herded the Bedouins into the enclosures so their children could be sent to school. But various policies have reduced the entire school age population to less than one school bus load. The most effective birth control has been the fact that escape from the enclosure for military age men is possible IF they join the IDF. Thus in the camps, you find few men, only women of fertile age, and the old of both sexes.

    In less than 25 years, the last Bedouin baby will be born and 60 of so years after that the world´s only 100% effective extermination of a people will be complete - the enclosures will no longer need guards.

    On one site, the new Israeli settlement being built discovered an old Bedouin grave yard. Israeli archeologists dated it as more than 5000 years old, but still the Bedouins have no right to that land needed for new Israeli settlers.

    * None the less, Israel will make small payment to those Bedouins who will sign papers renouncing their land claims.
    Last edited by a moderator: Feb 14, 2012
  11. Search & Destroy Take one bite at a time Moderator

    It's a good point Billy. For some reasons Americans like jungle people more than desert people though.

    If I may go more into the dam project and why it might not be beneficial, let me just quote this book I read yesterday

    Our Ecological Footprint:
    Mathis Wackernagel & William Rees

    I found it interesting as maybe you will, that by flooding such large areas this big damn actually becomes a lot less efficient overall for Brazil.
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Perhaps but of much more importance I think is who the oppressors are. If they can and do control nearly completely the flow of news about their oppression of a primitive people and never do anything sudden to achieve their annihilation (no gas chambers or firing squads, etc.) then the slow steady eradication of a people is not news worthy and certainly will not appear in US press and TV if Israel is the oppressor as that would have too great a cost to the newspaper and TV stations.

    Efficiency is not of much concern if the resource is essentially free or otherwise not being economically used - as is the case with the area to be flooded by new dam.

    What drives the real world is cost efficiency of meeting demands. Brazil has increasing demand for electric power as large part of its population is buying their first refrigerator, TV etc. I don´t have the numbers exact in my memory but about a decade ago >90% of Brazil´s electric power was hydroelectric. I think is it less than 80% now. If more hydro is not added, the cost per KWH will go up and that is why a few native Indians will be relocated. I.e. there are thousands who will benefit for every Indian relocated.

    To illustrate how important cost is I note that the energy releases as river flow down say 500 meters is a fixed number. It can be captured by a series of smaller dams, just as well as by one big one at the low point of the 500m fall. This series of small dams would flood only a small fraction of the land that the big one does, and produce essentially the same power or energy; however they would cost more to build and for power collection system, so big dams are built, large areas are flooded.

    Dams do change the way the land is used. As a youth living in W.Va. I went to the Norris Dam to fish on vacations. I am sure the net effect of that Dam has been a great economic benefit to the people living in that part of Tennessee. It was built by the Tennessee Valley Authority, TVA, and was opposed by the locals at the time of construction, but none now of the 100 or more times larger population of the area.

    Thus to finally answer your question: I support the construction of this new dam, as am quite confident the next generation of even the Indians being displaced by the rising water onto larger lands will. Some of that next generation will probably return to their father´s land, as operators of touristic boats, fishing centers, rustic camps, etc. perhaps fresh water shrimp farmers, etc. The economic value of how the land is being used will increase 5 fold every decade until 2042, I am quite sure, most of which will be the power, but employment will finally be the main source of the increase.
    Last edited by a moderator: Feb 16, 2012
  13. HectorDecimal Registered Senior Member

    This is the same as global warming theories. Is it natural, such as induced by the position of the magnetosphere's poles and the magnetic poles in relationship to the true poles, or is it because of the greenhouse effect or one feeding the other? We know most of the planet's oxygen comes from seaborne algae and phytoplankton, so this needs to be compared against the deforestation. It could also be as natural as the formation of once abundant springs that no longer feed tributories or geysers by natural depletion of the ground waters. It is too soon to tell, but in this age of expanding knowledge, inclusive of discussions like this, we may soon be able to tip the balance of evidence to resolve one way or the other.
  14. spidergoat Liddle' Dick Tater Valued Senior Member

    Oh please. Stop with the sensationalism. Israel just spent 1.5 billion dollars on new Bedouin settlements. That in spite of the fact that Bedouin gangs regularly kidnap and torture refugees bound for Israel.

    Egyptian authorities look the other way as Bedouin kidnap refugees
  15. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    spidergoat: Your link concernes Egypt, not Israel, and criminals who happen to be of mainly of Bedouin desent, but are not Bedouins by culture or life style - just criminals in Egypt looking for a easy profit. Certainly criminals should lose their rights. Certainly these Egyptian criminals are not justification for confining peaceful Israeli Bedouins in concentration camps and confiscating their lands.
    Where? Will they own the land and be free to sell it and leave? Or is this just some modernization of one of the Negev "enclosures" (concentration camps with guards, in fact)?

    I am not saying that in 25 or less years no Bedouin baby will be born any where in the world – just not have parents living in Israel´s Negev confinement “enclosures” Nor am I saying that there will be no “Bedouin genes” in later generations, as many young male Bedouins have joined the IDF to escape from the enclosures. Some will marry and have children. “Genetically pure” Bedouins soon will be extinct, probably even outside of Israel as most other states oppress them too.

    What is an accomplished fact, more than a decade old now, is that no Bedouins live as Bedouins in the Sinai or the Negev that Israel controls. Once, for more than 5000 years, they freely roamed the Sinai and Negev with their large herds of black goats. Certainly at their peak there were more than 100,000 Bedouins divided into several tribes and perhaps half a million animals. That culture has been destroyed, even their black goats are nearly extinct, but I think a few still survive in zoos.

    I am not saying that Israel, with larger, more modern, better educated population, could not, should not, do what advanced cultures almost always do to primitive peoples. I.e. put their land to more valuable economic use. It is just that it was not necessary to totally eliminate their culture by forced relocation into concentrations camps in the worst part of the Negev and now in generation more, eliminate all the Bedouins themselves in land Israel controls.

    Israel could have done more like the US did – make large viable reservations where the old life style could be practiced until later generations no longer want it. Israel, could have paid them fair compensation for their lands, recognized their old Ottoman deeds etc. –It did not need economically to just confiscate their land. Perhaps Israel feared setting some precedent the Palestinian could use legally?

    Brazil has many Indian tribes still living on large tracts of land and non-native can be arrested if they enter without tribal permission. Unfortunately, gold has been found on some of them and criminals do invade, and even kill, Indians, but the government does try to catch and jail these gold hungry criminals.

    The ironic thing is that for practical purposes “Never Again” means never again will Bedouins live as Bedouin anywhere in the land Israel controls as they did for more than 5000 years before there even was a state of Israel.

    But I will wait with hope, that you have reassuring answers to the questions I asked at the start of this post, (and credible links supporting them).

    I.e. WHERE? & will they own the land and have right to sell and leave?
    Last edited by a moderator: Feb 16, 2012
  16. arauca Banned Banned

    Could the earth sustain the present population if there would not be fossil fuel , Would we be able to grow enough tree to cook our food ?
  17. Liebling Doesn't Need to be Spoonfed. Valued Senior Member

    Well, here's the problem with the theory that it is fossil fuels alone that are causing the deforestation; a. agriculture b. clear cutting (manual deforestation) c. unsustainable population growth. d. longer dry seasons e. increased forest fires

    As humans colonize areas and build farms on land that was once a rain forest, it completely interupts the cycles of that particular biome. But biology plays a larger part in this. Since almost all cellular life on earth needs both sugars and carbon dioxide to survive, and plants are both the greatest contributor and storage units of carbon dioxide, cutting down trees that hold a very large carbon footprint compared to smaller annual crops, which hold considerably less. More carbon dioxide is released into the atmosphere and is not stored, thus contributing to the rise in tempurature since Carbon Dioxide itself is a greenhouse gas and affects the atmosphere's ability to retain heat.

    There are plants and trees that have a increased concentrations of carbon dioxide and those could have an impact on patterns of plant growth worldwide. There are species of plants that respond more favorably to increases in carbon dioxide than others, and we may experience global shifts in plant species that fare better in richer carbon dioxide conditions and balance it all out. The problem with that is we like to interfere, and as our population grows unsustainably, more agriculture will be needed to support that population and less attention will be paid to maintaining the balance.

    There is some evidence in the amazon rainforests that trees are adapting to hold a larger carbon footprint in response and are releasing more fertilization into it's own ecology to promote sapling and growth that is being depleted by humans. It's an interesting thing;

    Also, you might be interested to read this article on how letting tribes maintain the lands they have always lived in and stopping corporate and state funded poverty intiatives could help protect our delicate rain forests;
  18. arauca Banned Banned

    Lets assume to grow a tree it takes 30 years , how many tree would be necessary for a a clan of 10 people to build a house which normally last 30 years and to cook 2 meals for 10 persons per day the we have to multiply it for 30 years . So I visualize as population increases the end will be a complete deforestation
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    A field of sugar cane, grown to produce alcohol, which displaces gasoline fuel is obviously reducing the CO2 in the air annually. I.e. it preventing the release of X tons of fossil fuel carbon annually. If the field were instead a mature forest, it would be storing W tons of carbon, but not reducing the CO2 in the air every year. - It is a static system, neither adding to (assume no fires) nor reducing the CO2 in the air.

    Thus in the long term, where “long term” is more than (W / X) years, even clearing forest by fire to make field for growing cane helps limit the CO2 concentration build up in the air/ however, normally the wood of a mature forest is too valuable to just burn up. I.e. about half of the wood will end up as lumber in buildings or as furniture.

    Thus after approximately, W / (2X) years it better to replace even the mature forest with a field of growing sugar cane at least from the POV of reducing the global warming effects of man´s release of CO2.

    Does any one have numerical values for W & X ? (So we have an idea how many years is “long term.”) I would guess W / (2X) is significantly less than 20 years.
  20. Dinosaur Rational Skeptic Valued Senior Member

    There was a TV commercial or episode in which lumberjacks were bragging about their abilities. The following conversation was included.
    I did way more logging than that in the great Sahara Forrest.

    You are nuts: The Sahara is a desert.

    It is now, but it was not when I was there.​
    One of the people watching at the time claimed that north Africa was once mostly forrest/jungle & grasslands. He said that early human argicultural activities started the transition to desert. Carthage & some prior cultures were mentioned by him.

    I never checked into this claim & wonder if it has any validity. Note that our western dustbowls are alleged to be the result of farming activity.
  21. James R Just this guy, you know? Staff Member


    Did you write the opening post yourself, or copy it from somewhere else?
  22. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    There is some truth to that but mainly climate change was the cause. For about 2,000 years (10,000 to 8000 BC as I recall) there were trees, streams with fish as large as one foot long and even crocodiles in what is now only sand of the Sahara. Thousands of their remains have been found.

    There is also currently serious consideration of making the Sahara green again, but in fact it is still expanding southward.
  23. arauca Banned Banned


    I am so dumb I can not think for my self

    There is s saying in Spain . that Felipe ll deforested Spain when he build the armada to attack England . England had coal but did not wanted to use because it was dirty until they were they were forced to use coal because they were deforesting England . Mow let me hit you with this one. Thank God he prepared fossil fuels on the millions of years so that we will not deforest the land and make a desert , and we have an opportunity to develop other reusable fuels and mankind can continue live in this beautiful planet .
    I hope perhaps this answer your dumb question.
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